MedWorm: Parasitology

Ever-increasing complexities of diamidine and arsenical crossresistance in african trypanosomes.

Trends in Parasitology — Tue, 01 Jul 2008 04:00:00 +0100

Ever-increasing complexities of diamidine and arsenical crossresistance in African trypanosomes.

Trends Parasitol. 2008 Jul 1;

Authors: de Koning HP

The treatment of both human and veterinary African trypanosomiasis is still, to a large extent, dependent on diamidines and melaminophenyl arsenicals. Sixty years after the introduction of pentamidine, a large effort is being made to develop a new generation of diamidines for the treatment of sleeping sickness. However, given the reports of resistance to both diamidines and melaminophenyl arsenicals from the field, including crossresistance to both classes in single isolates, researchers should proceed with some caution before introducing new diamidines, and a thorough understanding of the causes of resistance and crossresistance will be essential.

PMID: 18599351 [PubMed - as supplied by publisher]

(Source: Trends in Parasitology)

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Flipping the paradigm on malaria transmission-blocking vaccines.

Trends in Parasitology — Tue, 01 Jul 2008 04:00:00 +0100

Flipping the paradigm on malaria transmission-blocking vaccines.

Trends Parasitol. 2008 Jul 1;

Authors: Dinglasan RR, Jacobs-Lorena M

The idea of malaria transmission-blocking vaccines (TBVs) surfaced more than two decades ago. Since then, the research paradigm focused on developing TBVs that target surface antigens of parasite sexual stages. Only recently has an effort emerged that flipped this paradigm, targeting antigens of the parasite's obligate invertebrate vector, the Anopheles mosquito. Here, we review the current state of knowledge of mosquito-based TBVs and discuss the utility of this approach for future vaccine development.

PMID: 18599352 [PubMed - as supplied by publisher]

(Source: Trends in Parasitology)

Fine targeting of purine salvage in cryptosporidium parasites.

Trends in Parasitology — Fri, 27 Jun 2008 04:00:00 +0100

Fine targeting of purine salvage in Cryptosporidium parasites.

Trends Parasitol. 2008 Jun 27;

Authors: Hyde JE

The apicomplexan pathogen Cryptosporidium parvum poses major logistical problems in the search for effective drug treatments. These treatments are required urgently because this parasite can cause severe disease and death in immunocompromised individuals and young children. In a recent study, the dependence of Cryptosporidium parasites on a single salvage pathway that leads to essential purine derivatives has been exploited and inhibitors have been identified that selectively target a key enzyme in this salvage process, inosine 5'-monophosphate dehydrogenase.

PMID: 18586557 [PubMed - as supplied by publisher]

(Source: Trends in Parasitology)

Protective immunity induced by daily bites from irradiated mosquitoes infected with plasmodium yoelii

Blackwell Synergy: Parasite Immunology: Table of Contents — Fri, 20 Jun 2008 01:13:53 +0100

Parasite Immunology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. SUMMARY Individuals in malaria endemic regions do not develop fully protective immune responses against Plasmodium liver stage infections. In high transmission areas, individuals can be exposed to more than two infective mosquito bites daily. Their ... (Source: Blackwell Synergy: Parasite Immunology: Table of Contents)

Lymphocyte hyporesponsiveness during filarial nematode infection

Blackwell Synergy: Parasite Immunology: Table of Contents — Thu, 19 Jun 2008 12:11:30 +0100

Parasite Immunology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. SUMMARY A frequently observed feature of active infection with filarial nematodes is the presence of lymphocytes in the bloodstream that have impaired responsiveness to antigen. It is generally accepted that such a defect in lymphocyte function could ... (Source: Blackwell Synergy: Parasite Immunology: Table of Contents)

Antigen selection for future anti-trichuris vaccines: a comparison of cytokine and antibody responses to larval and adult antigen in a primary infection

Blackwell Synergy: Parasite Immunology: Table of Contents — Thu, 19 Jun 2008 12:11:29 +0100

Parasite Immunology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. SUMMARY Trichuriasis, caused by the whipworm Trichuris trichiura, is endemic in tropical and subtropical areas, affecting approximately 1 billion people. Child anthelminthic treatment programmes are being implemented but repeated treatments are costly, ... (Source: Blackwell Synergy: Parasite Immunology: Table of Contents)

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Does resistance to filarial reinfections become leaky over time?

Trends in Parasitology — Thu, 19 Jun 2008 04:00:00 +0100

Does resistance to filarial reinfections become leaky over time?

Trends Parasitol. 2008 Jun 19;

Authors: Duerr HP, Hoffmann WH, Eichner M

Strategies for the control of human parasitic diseases such as onchocerciasis and lymphatic filariasis require an understanding of how the parasite successfully infects and persists in humans. Despite the fact that the vast majority of infective larvae are eliminated after infection, this 'protection' is far from being an all-or-nothing response. The hypothesis presented here, which is based on epidemiological observations, suggests that the resistance against filarial parasites includes a time-dependent component, probably caused by an early immune response with short-term memory. Validating this hypothesis requires experimental studies with a longitudinal component. Such experiments would help to clarify whether the infection can be controlled by vaccination strategies at all.

PMID: 18571986 [PubMed - as supplied by publisher]

(Source: Trends in Parasitology)

The roles of il-10 and tgf-beta in controlling il-4 and ifn-gamma production during experimental fasciola hepatica infection.

International Journal for Parasitology — Wed, 18 Jun 2008 04:00:00 +0100

The roles of IL-10 and TGF-beta in controlling IL-4 and IFN-gamma production during experimental Fasciola hepatica infection.

Int J Parasitol. 2008 Jun 18;

Authors: Flynn RJ, Mulcahy G

Hosts infected with Fasciola hepatica experience immunosuppression during the acute and chronic phases of the disease. This immunosuppression may allow parasite survival in the face of an ongoing immune response. In bovine hosts early IL-4 and continued IgG1 production is one of the few remaining features of the characteristic type 0/2 helper (Th0/2) response present in the chronic stage of disease. Here we demonstrate elevated levels of parasite-specific, in vitro peripheral blood mononuclear cell (PBMC)-derived transforming growth factor (TGF)-beta1 from the early phases of infection and increasing levels of IL-10 as the infection becomes chronic. In vitro neutralisation of these cytokines during culture of PBMCs from experimentally-infected cattle increased IL-4 and IFN-gamma production in response to parasite-specific and non-specific stimulation. At 4 weeks p.i. neutralisation of TGF-beta results in an increase in parasite driven IL-4, while also having a greater role, compared with IL-10, in influencing specific and non-specific IFN-gamma. At 12 weeks p.i. ex vivo parasite driven IL-4 was not restored by inhibiting either IL-10 or TGF-beta. However IL-10 influenced both parasite-specific and non-specific IFN-gamma production at this time. This highlights the roles of IL-10 and TGF-beta in fasciolosis, however the cellular sources of these have yet to be defined. This suggests that suppression of IFN-gamma production by parasite molecules occurs during infection and it is possible that the suppression of IFN-gamma production may mediate parasite survival in this disease.

PMID: 18597757 [PubMed - as supplied by publisher]

(Source: International Journal for Parasitology)

Multiple near-identical genotypes of schistosoma japonicum can occur in snails and have implications for population-genetic analyses.

International Journal for Parasitology — Thu, 12 Jun 2008 04:00:00 +0100

Multiple near-identical genotypes of Schistosoma japonicum can occur in snails and have implications for population-genetic analyses.

Int J Parasitol. 2008 Jun 12;

Authors: Yin M, Hu W, Mo X, Wang S, Brindley PJ, McManus DP, Davis GM, Feng Z, Blair D

We genotyped (using 16 or 17 microsatellite loci) numerous adult Schistosoma japonicum raised in rabbits exposed to pooled cercariae from small numbers of naturally infected snails from several localities in China. As expected, duplicate multi-locus genotypes (MLGs) were found among these worms. Additionally, many more MLGs, often near-identical, were found than snails used as sources of cercariae. Explanations for these results include (i) genotyping errors, (ii) development within each infected snail of multiple sibling miracidia and (iii) somatic mutation producing genetically varied cercariae from a single miracidium. To control for genotyping errors we re-analysed samples from many individual worms, including repeating the initial PCR. Explanations invoking the development of multiple sibling miracidia within a single snail are not likely to be correct because almost all duplicate MLGs fell within same-sex clusters in a principal coordinates analysis. We would expect both sexes to be represented in a multi-miracidium infection. In addition, we exposed several snails to infection by a single miracidium. One such snail, via an experimentally infected mouse, yielded 48 adult worms. The presence of at least nine near-identical MLGs among these worms was confirmed by re-genotyping. We regard somatic mutation as the most likely explanation for our results. The implications of multiple MLGs for population-genetic studies in S. japonicum are discussed.

PMID: 18590733 [PubMed - as supplied by publisher]

(Source: International Journal for Parasitology)

Cyclic nucleotide-specific phosphodiesterases of plasmodium falciparum: pfpdealpha, a non-essential cgmp-specific pde that is an integral membrane protein.

International Journal for Parasitology — Thu, 12 Jun 2008 04:00:00 +0100

Cyclic nucleotide-specific phosphodiesterases of Plasmodium falciparum: PfPDEalpha, a non-essential cGMP-specific PDE that is an integral membrane protein.

Int J Parasitol. 2008 Jun 12;

Authors: Wentzinger L, Bopp S, Tenor H, Klar J, Brun R, Beck HP, Seebeck T

Cyclic nucleotide-specific phosphodiesterases (PDEs) have come into focus as interesting potential targets for PDE inhibitor-based anti-parasitic drugs. Genomes of the various agents of human malaria, most notably Plasmodium falciparum, all contain four genes for class 1 PDEs. The catalytic domains of these enzymes are closely related to those of the 11 human PDE families. This presents the possibility that the available vast expertise in developing drugs against human PDEs might now also be applied to developing compounds that are active against malarial PDEs. The current study identifies four Plasmodium genes that code for PfPDEalpha, PfPDEbeta, PfPDEgamma and PfPDEdelta, respectively. It further demonstrates that the PfPDE1 polypeptide exists in two versions (PfPDEalphaA and PfPDEalphaB) that are generated by alternative splicing of the primary transcript. All malarial PDEs contain several transmembrane helices in their N-terminal regions, indicating that they are integral membrane proteins. In agreement with this prediction, essentially all PDE activity is associated with the cell membranes. PfPDEalpha was characterized as a cGMP-specific PDE that is not sensitive to a number of standard PDE inhibitors. Genetic ablation of the PfPDE1 gene produced no major phenotype in erythrocyte cultures.

PMID: 18590734 [PubMed - as supplied by publisher]

(Source: International Journal for Parasitology)

Infection of cattle with theileria parva induces an early cd8 t cell response lacking appropriate effector function.

International Journal for Parasitology — Thu, 12 Jun 2008 04:00:00 +0100

Infection of cattle with Theileria parva induces an early CD8 T cell response lacking appropriate effector function.

Int J Parasitol. 2008 Jun 12;

Authors: Houston EF, Taracha EL, Brackenbury L, Machugh ND, McKeever DJ, Charleston B, Morrison WI

Theileria parva causes an acute lympho-proliferative disease in cattle, which can result in death of susceptible animals within 2-3 weeks of infection. Analyses of the cellular response in the lymph node draining the site of infection demonstrated an early T cell response, with the appearance of large numbers of uninfected lymphoblasts between 6 and 9 days p.i., coinciding with initial detection of parasitised cells. There was a marked increase in the representation of CD8(+) T cells and the emergence of a sizable sub-population of CD2(-) CD8(+) alpha/beta T cells during this period. Analysis of T cell receptor beta chain variable (TCR BV) gene expression did not reveal any evidence for the involvement of a superantigen in stimulating the response. Responding lymph node cells were found to produce increased quantities of IFNgamma and IL-10, and both the CD2(+) CD8(+) and CD2(-) CD8(+) populations expressed IFNgamma transcripts. Purified CD2(+) CD8(+) cells proliferated when stimulated in vitro with autologous parasitised cells or non-specific mitogens, whereas CD2(-) CD8(+) cells were refractory to these stimuli. In contrast to the parasite-specific cytotoxic activity associated with T cell responses in immune cattle, the responses to primary infection exhibited variable levels of non-specific cytotoxic activity. Stimulation of purified CD2(+) CD8(+) T cells in vitro with autologous parasitised cells also failed to reveal evidence of specific cytotoxic activity. These findings indicate that primary infection with T. parva induces an aberrant T cell response that lacks appropriate effector activity.

PMID: 18590735 [PubMed - as supplied by publisher]

(Source: International Journal for Parasitology)

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Simple and sensitive antimalarial drug screening in vitro and in vivo using transgenic luciferase expressing plasmodium berghei parasites.

International Journal for Parasitology — Thu, 12 Jun 2008 04:00:00 +0100

Simple and sensitive antimalarial drug screening in vitro and in vivo using transgenic luciferase expressing Plasmodium berghei parasites.

Int J Parasitol. 2008 Jun 12;

Authors: Franke-Fayard B, Djokovic D, Dooren MW, Ramesar J, Waters AP, Falade MO, Kranendonk M, Martinelli A, Cravo P, Janse CJ

We report two improved assays for in vitro and in vivo screening of chemicals with potential anti-malarial activity against the blood stages of the rodent malaria parasite Plasmodiumberghei. These assays are based on the determination of luciferase activity (luminescence) in small blood samples containing transgenic blood stage parasites that express luciferase under the control of a promoter that is either schizont-specific (ama-1) or constitutive (eef1alphaa). Assay 1, the in vitro drug luminescence (ITDL) assay, measured the success of schizont maturation in the presence of candidate drugs quantifying luciferase activity in mature schizonts only (ama-1 promoter). The ITDL assay generated drug-inhibition curves and EC(50) values comparable to those obtained with standard in vitro drug-susceptibility assays. The second assay, the in vivo drug-luminescence (IVDL) assay, measured parasite growth in vivo in a standard 4-day suppressive drug test, monitored by measuring the constitutive luciferase activity of circulating parasites (eef1alphaa promoter). The IVDL assay generates growth-curves that are identical to those obtained by manual counting of parasites in Giemsa-stained smears. The reading of luminescence assays is rapid, requires a minimal number of handling steps and no experience with parasite morphology or handling fluorescence-activated cell sorters, produces no radioactive waste and test-plates can be stored for prolonged periods before processing. Both tests are suitable for use in larger-scale in vitro and in vivo screening of drugs. The standard methodology of anti-malarial drug screening and validation, which includes testing in rodent models of malaria, can be improved by the incorporation of such assays.

PMID: 18590736 [PubMed - as supplied by publisher]

(Source: International Journal for Parasitology)

Entamoeba histolytica: lipid rafts are involved in adhesion of trophozoites to host extracellular matrix components.

Experimental Parasitology — Thu, 12 Jun 2008 04:00:00 +0100

Entamoeba histolytica: Lipid rafts are involved in adhesion of trophozoites to host extracellular matrix components.

Exp Parasitol. 2008 Jun 12;

Authors: Mittal K, Welter BH, Temesvari LA

Adhesion is an important virulence function for Entamoeba histolytica, the causative agent of amoebic dysentery. Lipid rafts, cholesterol-rich domains, function in compartmentalization of cellular processes. In E. histolytica, rafts participate in parasite-host cell interactions; however, their role in parasite-host extracellular matrix (ECM) interactions has not been explored. Disruption of rafts with a cholesterol extracting agent, methyl-beta-cyclodextrin (MbetaCD), resulted in inhibition of adhesion to collagen, and to a lesser extent, to fibronectin. Replenishment of cholesterol in MbetaCD-treated cells, using a lipoprotein-cholesterol concentrate, restored adhesion to collagen. Confocal microscopy revealed enrichment of rafts at parasite-ECM interfaces. A raft-resident adhesin, the galactose/N-acetylgalactosamine-inhibitable lectin, mediates interaction to host cells by binding to galactose or N-acetylgalactosamine moieties on host glycoproteins. In this study, galactose inhibited adhesion to collagen, but not to fibronectin. Together these data suggest that rafts participate in E. histolytica-ECM interactions and that raft-associated Gal/GalNAc lectin may serve as a collagen receptor.

PMID: 18588878 [PubMed - as supplied by publisher]

(Source: Experimental Parasitology)

Efficient expression of a toxoplasma gondii dense granule gra4 antigen in tobacco leaves.

Experimental Parasitology — Tue, 10 Jun 2008 04:00:00 +0100

Efficient expression of a Toxoplasma gondii dense granule Gra4 antigen in tobacco leaves.

Exp Parasitol. 2008 Jun 10;

Authors: Ferraro G, Becher ML, Angel SO, Zelada A, Mentaberry AN, Clemente M

A His-tagged truncated version of Toxoplasma gondii dense granule 4 protein (Gra4(163-345)) was transiently expressed in tobacco leaves. Two genetic constructions were used to accomplish this goal. In one of them, based in a Potato virus X (PVX) amplicon, the sequence encoding His-Gra4(163-345) was placed under control of an additional PVX coat protein subgenomic promoter. In the other, the same sequence was fused to an apoplastic transport signal and placed under the direction of the cauliflower mosaic virus 35S promoter. His-Gra4(163-345) accumulation in agroinfiltrated tobacco leaves was estimated by Western blot analysis using mouse anti-Gra4 antibody and a seropositive human serum. Here, we demonstrated the feasibility of producing a Gra4 antigen using transient expression methods in plants.

PMID: 18588877 [PubMed - as supplied by publisher]

(Source: Experimental Parasitology)

Schistosoma mansoni: human skin ceramides are a chemical cue for host recognition of cercariae.

Experimental Parasitology — Sun, 08 Jun 2008 04:00:00 +0100

Schistosoma mansoni: Human skin ceramides are a chemical cue for host recognition of cercariae.

Exp Parasitol. 2008 Jun 8;

Authors: Haas W, Haeberlein S, Behring S, Zoppelli E

Schistosoma mansoni cercariae recognize the human host with a sequence of behavioral responses particularly to chemical host cues. After attaching to the skin surface, cercariae are stimulated by so far unknown skin components to hold enduring contact with the skin and to start creeping towards entry sites. We studied the chemical stimulus of human skin for the cercarial enduring contact response by fractionation of human and pig skin surface extracts and offering the fractions to the cercariae via membrane filters. Enduring contact was stimulated exclusively by ceramides, specific lipids of the uppermost skin layers. This chemical cue differs from the 6 chemical host signals used by S. mansoni cercariae in other behavioral steps of host invasion, and thus underlines the specialization of S. mansoni cercariae particularly in chemical host signals. All together, the enduring contact response of the cercariae is, like the other phases of host invasion, well adapted to the chemical properties of human skin.

PMID: 18585383 [PubMed - as supplied by publisher]

(Source: Experimental Parasitology)

A revision of patagifer dietz, 1909 (digenea: echinostomatidae) and a key to its species.

Systematic Parasitology — Sat, 07 Jun 2008 22:20:49 +0100

A revision of Patagifer Dietz, 1909 (Digenea: Echinostomatidae) and a key to its species.

Syst Parasitol. 2008 Jul;70(3):159-83

Authors: Faltýnková A, Gibson DI, Kostadinova A

Patagifer Dietz, 1909 is revised and a key to the species is presented. P. oweni n. sp. is described from Threskiornis molucca (Cuvier) in the Western Province of Papua New Guinea and distinguished from the related P. chandrapuri Srivastava, 1952 by: the shape of the pair of large angle spines (cudgel-shaped vs sub-rectangular); pointed (vs rod-shaped) marginal spines; a smaller body and internal organs; more anteriorly located testes; and larger eggs. The new species differs from P. brygooi Richard, 1964 in its larger body, head collar, suckers, pharynx and eggs, longer oesophagus and testes, the latter being also more elongate and more anteriorly located, and a different number of collar spines (61-62 vs 59). P. bilobus (Rudolphi, 1819) (the type-species), P. parvispinosus Yamaguti, 1933, P. chandrapuri and P. vioscai Lumsden, 1962 are redescribed on the basis of museum and newly collected material. The variations in the number and size of the collar spines and other metrical characters of P. bilobus are studied in two different host species from Europe, Plegadis falcinellus and Platalea leucorodia. Other species considered valid are: Patagifer consimilis Dietz, 1909, P. acuminatus Johnston, 1917, P. fraternus Johnston, 1917, P. wesleyi Verma, 1936, P. brygooi and P. toki Onda, Imai & Ishii, 1983. P. plegadisi Sakla, Monib & Mandour, 1988 and P. simarai Nigam, 1944 are considered synonyms of P. bilobus, and P. sarai Saksena, 1957 is placed in synonymy with P. chandrapuri. Forms considered dubious are: P. bilobus of Machida et al. (Jpn J Parasitol 15:339, 1966) and Machida (Bull Natl Sci Mus Tokyo 11:157-160, 1968), P. simerai [sic] of Mehra (The fauna of India and adjacent countries. Platyhelminthes, 1980), P. skrjabini Hilmy, 1949 sp. inq. and P. srivastavai Peter, 1954 sp. inq. Lists of the records and hosts of the 11 valid species are included.

PMID: 18535788 [PubMed - in process]

(Source: Systematic Parasitology)

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Ectoparasites of rodents in southern africa: a new species of androlaelaps berlese, 1903 (acari: parasitiformes: laelapidae) from rhabdomys pumilio (sparrman) (rodentia: muridae).

Systematic Parasitology — Sat, 07 Jun 2008 22:20:46 +0100

Ectoparasites of rodents in Southern Africa: a new species of Androlaelaps Berlese, 1903 (Acari: Parasitiformes: Laelapidae) from Rhabdomys pumilio (Sparrman) (Rodentia: Muridae).

Syst Parasitol. 2008 Jul;70(3):185-90

Authors: Matthee S, Ueckermann EA

Androlaelaps rhabdomysi n. sp. is described from the pelage of the endemic rodent Rhabdomys pumilio (Sparrman) in the Western Cape Province, South Africa. The formal taxonomic description and illustrations are derived from adults (female and male) and deutonymphs. The specimens are similar in appearance to two congeneric species A. dasymys (Radford, 1939) and A. fahrenholzi (Berlese, 1911), but differ in the following features: genital shield long and almost parallel-sided; metapodal shield elongate; and anal shield longer than wide. Furthermore, the pilus dentilis on the fixed cheliceral digit of A. rhabdomysi is a rather broad sausage-shape and slightly constricted medially, whereas in the other two species it has an inflated base and is slender distally.

PMID: 18535789 [PubMed - in process]

(Source: Systematic Parasitology)

Species of triacanthinella bychowsky & nagibina, 1968 (monogenea: ancyrocephalidae) from triacanthid teleosts off peninsular malaysia, with a generic revision, amended diagnosis and key.

Systematic Parasitology — Sat, 07 Jun 2008 22:20:43 +0100

Species of Triacanthinella Bychowsky & Nagibina, 1968 (Monogenea: Ancyrocephalidae) from triacanthid teleosts off Peninsular Malaysia, with a generic revision, amended diagnosis and key.

Syst Parasitol. 2008 Jul;70(3):191-213

Authors: Lim LH, Gibson DI

One new and four previously described species of Triacanthinella Bychowsky & Nagibina, 1968 (Monogenea) were collected from the tripodfishes Triacanthus biaculeatus and Tripodichthys blochii off Peninsular Malaysia. Triacanthinella lumutensis n. sp. from Tripodichthys blochii off Lumut, Selangor is similar to Triacanthinella principalis Bychowsky & Nagibina, 1968 in having morphologically similar types of haptoral sclerites and copulatory organ, but differs in possessing a longer copulatory tube. Also re-described are T. principalis Bychowsky & Nagibina, 1968, T. gracilis Bychowsky & Nagibina, 1968 and T. aspera Bychowsky & Nagibina, 1968 from both Triacanthus biaculeatus and Tripodichthys blochii, plus Triacanthinella longipenis Bychowsky & Nagibina, 1968 from Tripodichthys blochii and Triacanthinella tripathii Bychowsky & Nagibina, 1968 based on its type-material. In the new species, the filament loop of the anchors is associated with a sheath-like sclerite which envelops the anchor point. Such sclerites were also observed in the present specimens of Triacanthinella principalis, T. aspera, T. longipenis and T. gracilis but were not mentioned in the original descriptions. The generic diagnosis of Triacanthinella is amended and a key to the recognised species is presented. The specific names of two of the previously described species are emended from the neuter form to T. principalis and T. gracilis.

PMID: 18535790 [PubMed - in process]

(Source: Systematic Parasitology)

Xiphinema pirinense n. sp. (nematoda: dorylaimida: longidoridae), a new species from bulgaria with a digitate tail.

Systematic Parasitology — Sat, 07 Jun 2008 22:20:39 +0100

Xiphinema pirinense n. sp. (Nematoda: Dorylaimida: Longidoridae), a new species from Bulgaria with a digitate tail.

Syst Parasitol. 2008 Jul;70(3):215-22

Authors: Mincheva Y, Lazarova S, Peneva V

A description of Xipinema pirinense n. sp. is provided. This is a parthenogenetic nematode found associated with Fragaria sp. and Alchemilla sp. (Rosaceae) close to pine trees in the Pirin Mountains, Bulgaria. The species is characterised by its medium body length (3.2-3.9 mm), rounded head region slightly demarcated by a shallow depression, long odontostyle (116-134.5 mum), tripartite uterus with a Z-differentiation consisting of 4-7 irregular moderately refractive bodies with a clear central part, and a digitate tail with a ventral peg. The new species is most similar to X. index Thorne & Allen, 1950 and X. diversicaudatum (Micoletzky, 1927) Thorne, 1939.

PMID: 18535791 [PubMed - in process]

(Source: Systematic Parasitology)

The taxonomic status of spatulifer cf. maringaensis pavanelli & rego, 1989 (eucestoda: proteocephalidea) from sorubim lima (bloch & schneider) (pisces: siluriformes), and the use of the microthrix pattern in the discrimination of spatulifer spp.

Systematic Parasitology — Sat, 07 Jun 2008 22:20:36 +0100

The taxonomic status of Spatulifer cf. maringaensis Pavanelli & Rego, 1989 (Eucestoda: Proteocephalidea) from Sorubim lima (Bloch & Schneider) (Pisces: Siluriformes), and the use of the microthrix pattern in the discrimination of Spatulifer spp.

Syst Parasitol. 2008 Jul;70(3):223-36

Authors: Arredondo NJ, Gil de Pertierra AA

de Chambrier & Vaucher (1999) compared the proteocephalidean cestode Spatulifer maringaensis Pavanelli & Rego, 1989 from Hemisorubim platyrhynchos (Valenciennes) with similar specimens, which they described as S. cf. maringaensis, parasitising Sorubim lima (Bloch & Schneider) collected in the Paraná and Paraguay Rivers. No remarkable differences between these worms were found by these authors, except for the scolex diameter and a different infection rate in each fish host. In order to elucidate the taxonomic status of the fish cestode Spatulifer cf. maringaensis from Sorubim lima, type and voucher material of S. maringaensis from H. platyrhynchos, and voucher and new material recently collected from Sorubim lima in Argentina are described in terms of their internal morphology and tegumental surface. During the study, mature and gravid worms with smaller metascoleces were found among voucher specimens from both hosts and in the new material from S. lima. The number of testes in the type-material was difficult to assess, but it could be determined in the voucher material from the type-host as being within the range of the specimens from S. lima. Both taxa are morphologically identical and can therefore be considered as conspecific. The data on their parasitological indices support the idea that S. lima is the principal final host and H. platyrhynchos is a secondary final host. Spatulifer maringaensis is widespread throughout the Paraná basin. A comparison of the microthrix pattern of S. maringaensis with that of S. rugosa (Woodland, 1935) revealed that they have the same type of microtriches, but with a different distribution, size and density. Tumuli were observed for the first time in a Neotropical taxon. Some studies have shown that the microthrix pattern is useful for characterising and discriminating species of the Proteocephalidea, and it was used herein as a tool for determining the conspecificity of S. cf. maringaensis with S. maringaensis.

PMID: 18535792 [PubMed - in process]

(Source: Systematic Parasitology)

Vitellocyte-specific expression of phospholipid hydroperoxide glutathione peroxidases in clonorchis sinensis.

International Journal for Parasitology — Sat, 07 Jun 2008 04:00:00 +0100

Vitellocyte-specific expression of phospholipid hydroperoxide glutathione peroxidases in Clonorchis sinensis.

Int J Parasitol. 2008 Jun 7;

Authors: Cai GB, Bae YA, Kim SH, Sohn WM, Lee YS, Jiang MS, Kim TS, Kong Y

Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is a major antioxidant enzyme and may protect against lipid hydroperoxidation in biomembranes. We isolated full-length cDNA sequences encoding four different PHGPxs from a causative agent of cholangiocarcinoma, Clonorchis sinensis (CsGPx1, CsGPx2, CsGPx3 and CsGPx4). These sequences contained an in-frame TGA codon for selenocysteine (Sec) and a concurrent Sec insertion sequence in their 3'-untranslated regions. The open reading frames were composed of six exons in the chromosomal segments of CsGPx1 (7705bp), CsGPx2 (5871bp), and CsGPx3 (3867bp), and five exons in CsGPx4 (5655bp). The positions of these introns were tightly conserved between the trematode and vertebrate PHGPx genes. Oxidative stimulation of viable worms with H(2)O(2) or paraquat resulted in 1.5- to 2-fold induction of the GPx activity. The CsGPx proteins were specifically localised in vitellocytes within vitelline follicles and premature eggs in the proximal uterus. In the eggs, glutathione, an electron donor for GPx, was co-localised with the CsGPx proteins, while thioredoxin, which is preferred by peroxiredoxin, was principally detected in the extracellular space between the embryonic cell mass and an eggshell. Our data may suggest a concerted or a specialised function between a thioredoxin-dependent enzyme(s) and GPx in protecting against H(2)O(2)-derived damage during maturation of the embryo and formation of the eggshell, in these catalase-lacking trematode parasites. The uniquely conserved genomic organisation and Sec-dependency amongst trematode and vertebrate PHGPx homologues will also provide insight into the evolutionary episode and functional/biochemical diversification of GPx proteins.

PMID: 18588894 [PubMed - as supplied by publisher]

(Source: International Journal for Parasitology)

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The effect of corticosteroid treatment on local immune responses, intake and performance in lambs infected with teladorsagia circumcincta.

International Journal for Parasitology — Fri, 06 Jun 2008 04:00:00 +0100

The effect of corticosteroid treatment on local immune responses, intake and performance in lambs infected with Teladorsagia circumcincta.

Int J Parasitol. 2008 Jun 6;

Authors: Greer AW, Huntley JF, Mackellar A, McAnulty RW, Jay NP, Green RS, Stankiewicz M, Sykes AR

The nutritional cost of, and the sequential cellular changes associated with the developing immune response to the abomasal parasite Teladorsagia circumcincta were investigated using corticosteroid-induced immune-suppression. Six-month-old lambs with minimal nematode experience were either infected with 4000 L3 T. circumcincta per day (group IF), similarly infected and concurrently immune-suppressed with methylprednisolone acetate (group ISIF), immune-suppressed only (group IS) or remained as controls (group C). Food intake, faecal egg count (FEC) and antibody titres in plasma were recorded weekly, worm burden at necropsy on day 63 p.i. and body composition by X-ray computed tomography on days -2 and 62 p.i. Furthermore, sequential immunological changes at the site of parasite infestation in the abomasal mucosa were measured from serial biopsy tissue samples taken from additional animals that were fitted with an abomasal cannula and either infected with the same regime as IF animals above (group CnIF) or concurrently infected and immune-suppressed as above (group CnISIF). Corticosteroid treatment resulted in greater FECs (P<0.01) and worm burdens (P<0.01) in both ISIF and CnISIF compared with IF and CnIF sheep, respectively. Infection reduced feed intake by 17% between 14 and 28 days p.i. (P<0.05) and efficiency of energy utilisation by 20% (P=0.07) in IF animals but not in ISIF animals. Mast cells, globule leukocytes and IgA in tissue biopsy samples were elevated in CnIF from 42 days p.i., all of which were abrogated by corticosteroid treatment. The ability to regulate the worm population appeared to be associated with a rise in tissue IgA concentration and numbers of globule leucocytes (GL). The results support the hypothesis that a majority of the production losses that occur during infection of lambs with T. circumcincta in lambs are a consequence of the host immune response. These findings may have implications for regimes that promote the development of a strong host immune reaction to gastrointestinal parasites in lambs.

PMID: 18577386 [PubMed - as supplied by publisher]

(Source: International Journal for Parasitology)

Stochastic induction of theileria annulata merogony in vitro by chloramphenicol.

International Journal for Parasitology — Thu, 05 Jun 2008 04:00:00 +0100

Stochastic induction of Theileria annulata merogony in vitro by chloramphenicol.

Int J Parasitol. 2008 Jun 5;

Authors: Schmuckli-Maurer J, Shiels B, Dobbelaere DA

Theileria annulata inhabits the cytoplasm of bovine leukocytes where it can be found as a multinucleated schizont. The schizont is the pathogenic stage of the life cycle and by interfering with host signalling pathways, it induces unlimited host cell proliferation and protection against apoptosis. In the infected animal, the schizont differentiates to the merozoite life cycle stage in a process called merogony. This takes place within the host leukocyte, resulting in the production of merozoites that are subsequently released by leukocyte lysis. In established cultures of T. annulata-transformed cells, merogony does not spontaneously occur, but the process can be activated by a shift in temperature. In this study we show that chloramphenicol induces schizont differentiation in proliferating T. annulata-transformed cells. We demonstrate that chloramphenicol-induced merogony is inherently asynchronous and has a quantitative basis. The process is accompanied by the down-regulation of schizont-specific surface proteins, de novo expression of merozoite-specific markers such as Tamr1 and Tams1 and the morphological hallmarks of merogony. Chloramphenicol-induced parasite differentiation was found to be associated with diminished proliferation potential and extensive morphological changes of the host cell, including increased numbers of pseudopodia. Significantly, chloramphenicol treatment can accelerate merogony induced by elevated temperature, supporting postulation that the differentiation event is a stochastic process that can be manipulated to alter the outcome of parasitic infection.

PMID: 18573257 [PubMed - as supplied by publisher]

(Source: International Journal for Parasitology)

Plasmodium falciparum shows transcriptional versatility within the human host.

Trends in Parasitology — Thu, 05 Jun 2008 04:00:00 +0100

Plasmodium falciparum shows transcriptional versatility within the human host.

Trends Parasitol. 2008 Jun 5;

Authors: Lovegrove FE, Peña-Castillo L, Liles WC, Hughes TR, Kain KC

In a recent study published in Nature, Daily et al. profiled parasite gene expression in Plasmodium falciparum infections and identified three in vivo 'states' based on parasite transcription patterns. Despite similar host clinical features, two states displayed highly divergent gene expression, whereas the third was found in individuals with increased inflammatory markers. These findings suggest that parasites exist in different physiological states in vivo, providing an important foundation for future studies investigating how these states might contribute to malaria pathogenesis and outcome.

PMID: 18538633 [PubMed - as supplied by publisher]

(Source: Trends in Parasitology)

The predicted impact of immunosuppression upon population age–intensity profiles for schistosomiasis

Blackwell Synergy: Parasite Immunology: Table of Contents — Tue, 03 Jun 2008 18:43:08 +0100

Parasite Immunology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. SUMMARY The slow development of acquired immunity is thought to be responsible for the characteristic convex age–intensity curve seen in human schistosome infection, which peaks earlier in more heavily infected populations (this is described as a peak ... (Source: Blackwell Synergy: Parasite Immunology: Table of Contents)

C3 contributes to the cross-protective immunity induced by babesia gibsoni phosphoriboprotein p0 against a lethal b. rodhaini infection

Blackwell Synergy: Parasite Immunology: Table of Contents — Tue, 03 Jun 2008 09:16:26 +0100

Parasite Immunology, Volume 30, Issue 6-7, Page 365-370, June/July 2008. SUMMARY We have studied the impact of complement component 3 (C3) deficiency on the progression of lethal Babesia rodhaini infection in immune mice. A B. gibsoni ribosomal phosphoprotein P0 (BgP0) previously reported to be a cross-protective antigen ... (Source: Blackwell Synergy: Parasite Immunology: Table of Contents)

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Complex i of trypanosomatidae: does it exist?

Trends in Parasitology — Tue, 03 Jun 2008 04:00:00 +0100

Complex I of Trypanosomatidae: does it exist?

Trends Parasitol. 2008 Jun 3;

Authors: Opperdoes FR, Michels PA

The presence of complex I, or NADH dehydrogenase, in Trypanosomatidae is debated. Several subunits of complex I have been identified by biochemical studies, but the overall composition of the complex has remained elusive. Here, the authors review the present literature related to this mitochondrial activity and carry out a bioinformatic analysis to allow the prediction of the composition of a putative trypanosomatid complex I. The complex comprises at least 19 subunits and has a minimum mass of 660kDa. It is larger than the corresponding bacterial enzyme but smaller than the typical mitochondrial enzyme of eukaryotes. All subunits known to be involved in electron transport are present, but the complex does not seem to be involved in energy transduction because four membrane subunits, normally encoded by the mitochondrial genome and supposed to be involved in proton extrusion, are missing.

PMID: 18534909 [PubMed - as supplied by publisher]

(Source: Trends in Parasitology)

Paragonimiasis: an important food-borne zoonosis in china.

Trends in Parasitology — Fri, 30 May 2008 04:00:00 +0100

Paragonimiasis: an important food-borne zoonosis in China.

Trends Parasitol. 2008 May 30;

Authors: Liu Q, Wei F, Liu W, Yang S, Zhang X

The lung fluke, Paragonimus westermani, is of major socioeconomic importance in Asia. The parasite is transmitted via snails to freshwater crabs or crayfish, then to humans and other mammals, such as cats and dogs, and causes paragonimiasis. This review provides a background on the parasite and its life cycle; summarizes key aspects regarding the pathogenesis, diagnosis and treatment of paragonimiasis; describes the geographic distribution and prevalence of paragonimiasis; and makes some recommendations for future research and the control of this important disease in China.

PMID: 18514575 [PubMed - as supplied by publisher]

(Source: Trends in Parasitology)

Why apply ecological laws to epidemiology?

Trends in Parasitology — Fri, 30 May 2008 04:00:00 +0100

Why apply ecological laws to epidemiology?

Trends Parasitol. 2008 May 30;

Authors: Morand S, Krasnov B

Using ecological laws, or rules, is a useful strategy for epidemiological observations. The application of Taylor's power law to epidemiology and evolutionary ecology of parasites is exemplified here. Taylor's power law takes the form of s(2)=am(b), where s(2) is the variance in population abundance, m is the mean abundance of the population, a represents a constant parameter and b represents an index of spatial heterogeneity. Although Taylor's power law reflects the aggregation of parasite (or pathogen) individuals among host population, the values of b could reflect regulation processes in host-parasite systems. Illustrations are given showing how b value is linked to various epidemiological situations: pathogen emergence, the impact of vaccination or the level of host immune defence.

PMID: 18514576 [PubMed - as supplied by publisher]

(Source: Trends in Parasitology)

Plasmodium falciparum: development of a transgenic line for screening antimalarials using firefly luciferase as the reporter.

Experimental Parasitology — Thu, 29 May 2008 04:00:00 +0100

Plasmodium falciparum: Development of a transgenic line for screening antimalarials using firefly luciferase as the reporter.

Exp Parasitol. 2008 May 29;

Authors: Cui L, Miao J, Wang J, Li Q, Cui L

High-throughput screening (HTS) of small-molecule libraries against pharmacological targets is a key strategy of contemporary drug discovery. This study reports a simple, robust, and cell-based luminescent method for assaying antimalarial drugs. Using transfection technology, we generated a stable Plasmodium falciparum line with high levels of firefly luciferase expression. A luciferase assay based on this parasite line was optimized in a 96-well plate format and used to compare with the standard [(3)H] hypoxanthine radioisotope method. The 50% inhibitory concentrations (IC(50)s) of chloroquine, artesunate, artemether, dihydroartemisinin and curcumin obtained by these two methods were not significantly different (P>0.05, ANOVA). In addition, this assay could be performed conveniently with a luminescence plate reader using unsynchronized stages within as early as 12h. Furthermore, the luciferase assay is robust with a Z' score of 0.77-0.92, which suggests the feasibility for further miniaturization and automation.

PMID: 18579134 [PubMed - as supplied by publisher]

(Source: Experimental Parasitology)

Identification of zoonotic giardia genotypes in marsupials in australia.

Experimental Parasitology — Thu, 29 May 2008 04:00:00 +0100

Identification of zoonotic Giardia genotypes in marsupials in Australia.

Exp Parasitol. 2008 May 29;

Authors: Thompson J, Yang R, Power M, Hufschmid J, Beveridge I, Reid S, Ng J, Armson A, Ryan U

A total of 421 fecal samples from a variety of captive and wild marsupial hosts in Western Australia, Victoria and South Australia were screened for the presence of Giardia species/genotypes using PCR and sequence analysis of a fragment of the 18S rRNA gene. Giardia spp. were identified in 13.4% (28/209) of samples from captive marsupials and 13.7% (29/212) of samples from wild marsupials. Sequence analysis at the 18S locus identified the zoonotic Giardia duodenalis Genotypes A and B in both captive and wild marsupials. Eight isolates were typed as genotype B3 and B4 at the gdh locus, although 7/8 were typed as genotype A at the 18S rRNA locus. The possible reasons for this discordance are discussed. This is the first report of genotype B and only the second report of genotype A in marsupials. As some of the genotype B isolates were identical to human-derived Giardia gdh sequences, these results suggest that marsupials in catchments may pose a public health risk and therefore warrant further investigation.

PMID: 18579135 [PubMed - as supplied by publisher]

(Source: Experimental Parasitology)

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Mast cells are activated by leishmania mexicana lpg and regulate the disease outcome depending on the genetic background of the host

Blackwell Synergy: Parasite Immunology: Table of Contents — Wed, 28 May 2008 18:49:01 +0100

Parasite Immunology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. SUMMARY The regulatory effect of mast cells on the pathogenesis of leishmaniasis is unclear. We report a comparative analysis of TLR2 membrane expression, TNF-α, IL-10 and MIP-1α production, and granule release of bone marrow-derived mast cells (BMMCs) ... (Source: Blackwell Synergy: Parasite Immunology: Table of Contents)

Canine leishmaniosis - new concepts and insights on an expanding zoonosis: part one.

Trends in Parasitology — Wed, 28 May 2008 04:00:00 +0100

Canine leishmaniosis - new concepts and insights on an expanding zoonosis: part one.

Trends Parasitol. 2008 May 28;

Authors: Baneth G, Koutinas AF, Solano-Gallego L, Bourdeau P, Ferrer L

Recent research has provided new insights on the epidemiology, pathology and immunology of canine leishmaniosis (CanL) and its genetic basis. The prevalence of infection in endemic areas is considerably higher than that of apparent clinical illness. In addition, infection spreads rapidly among dogs in the presence of optimal conditions for transmission. Infection involves a variety of granulomatous and harmful immune-mediated responses, and susceptibility to the disease is influenced by a complex genetic basis. These concepts will be instrumental for devising control programs. This review, the first in a series of two articles on CanL, presents an updated view on progress in elucidating the epidemiology and pathogenesis of this challenging disease, and the second part focuses on advances in diagnosis, treatment and prevention.

PMID: 18514028 [PubMed - as supplied by publisher]

(Source: Trends in Parasitology)

What are the respective host and parasite contributions to toxoplasmosis?

Trends in Parasitology — Wed, 28 May 2008 04:00:00 +0100

What are the respective host and parasite contributions to toxoplasmosis?

Trends Parasitol. 2008 May 28;

Authors: Maubon D, Ajzenberg D, Brenier-Pinchart MP, Dardé ML, Pelloux H

The toxoplasmosis pathogenesis mechanism is complex because parasite and host specificities are interrelated. Advances in fundamental research (including strain genotyping, analyzing the progeny from crosses of different strains and exploring the implication of epigenetic effects on the parasite) have contributed greatly to our current knowledge of this mechanism. At the same time new data on the clinical characteristics of the disease have come to light. For example, highly virulent strains have been isolated recently in immunocompetent patients, and some studies suggest that toxoplasmosis also might be implicated in brain disorders. These recent tools and discoveries are likely to cast new light on the pathogenicity of Toxoplasma parasites and provide the key to understanding this unique form of parasitism.

PMID: 18514029 [PubMed - as supplied by publisher]

(Source: Trends in Parasitology)

Abc transporter modulation: a strategy to enhance the activity of macrocyclic lactone anthelmintics.

Trends in Parasitology — Wed, 28 May 2008 04:00:00 +0100

ABC transporter modulation: a strategy to enhance the activity of macrocyclic lactone anthelmintics.

Trends Parasitol. 2008 May 28;

Authors: Lespine A, Alvinerie M, Vercruysse J, Prichard RK, Geldhof P

The emergence of parasites resistant to anthelmintic macrocyclic lactones (MLs) threatens to severely limit current parasite control strategies. Improving the current ML-based chemotherapy to perpetuate the efficacy of this broad-spectrum class of anthelmintics would be advantageous. In recent years it has become evident that the absorption, distribution and elimination of the MLs in hosts and parasites are under the control of multidrug resistance transporters (MDRs) such as P-glycoproteins. Theoretically, the inhibition of these transporters should result in an increase of the drug concentration in the organisms and higher treatment efficiency. This opinion article will discuss the recent findings in this research field and assess the possibilities of this approach being used in the field.

PMID: 18514030 [PubMed - as supplied by publisher]

(Source: Trends in Parasitology)

The maurer's clefts of plasmodium falciparum: parasite-induced islands within an intracellular ocean.

Trends in Parasitology — Wed, 28 May 2008 04:00:00 +0100

The Maurer's clefts of Plasmodium falciparum: parasite-induced islands within an intracellular ocean.

Trends Parasitol. 2008 May 28;

Authors: Przyborski JM

It is suggested that Maurer's clefts, membranous structures observed within the cytoplasm of Plasmodium-falciparum-infected human erythrocytes, play an important role in trafficking virulence proteins from the parasite to the surface of the host cell. How they fulfil this role, however, still is unclear. A recent study by Bhattacharjee et al. now suggests that the clefts function as the major conduit through which parasite-encoded proteins pass before entering the host cell. In this article we comment on the significance of this information in our understanding of the novel 'extracellular' secretory pathway of this important human pathogen.

PMID: 18514031 [PubMed - as supplied by publisher]

(Source: Trends in Parasitology)

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Toxocara canis larval excretory/secretory proteins impair eosinophil-dependent resistance of mice to nippostrongylus brasiliensis

Blackwell Synergy: Parasite Immunology: Table of Contents — Wed, 28 May 2008 00:28:38 +0100

Parasite Immunology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. SUMMARY Survival of parasitic helminths within a host requires immune evasion and excretory/secretory (ES) proteins may contribute to this process. Eosinophils are important effector cells in immunity of mice to the nematode Nippostrongylus brasiliensis ... (Source: Blackwell Synergy: Parasite Immunology: Table of Contents)

Towards a differential definition of atopy: anisakis simplex and the relationship between parasites and arthropods in respiratory allergy

Blackwell Synergy: Parasite Immunology: Table of Contents — Mon, 26 May 2008 07:25:42 +0100

Parasite Immunology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. SUMMARY Protective as well as enhancing effects of parasite infections on allergic disease have been postulated. Previous studies on this relationship focused frequently on skin test reactivity against aeroallergens, being house dust mites (HDM) the main ... (Source: Blackwell Synergy: Parasite Immunology: Table of Contents)

Demonstration of strain-specific cd8 t cell responses to theileria annulata

Blackwell Synergy: Parasite Immunology: Table of Contents — Thu, 22 May 2008 18:51:13 +0100

Parasite Immunology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. SUMMARY The present study set out to examine the nature and specificity of the bovine CD8 T cell response at the clonal level in a group of eight animals immunized with a cloned population of Theileria annulata. The results demonstrated that immunized ... (Source: Blackwell Synergy: Parasite Immunology: Table of Contents)

Nematode lungworms of two species of anuran amphibians: evidence for co-adaptation.

International Journal for Parasitology — Thu, 22 May 2008 04:00:00 +0100

Nematode lungworms of two species of anuran amphibians: Evidence for co-adaptation.

Int J Parasitol. 2008 May 22;

Authors: Dare OK, Nadler SA, Forbes MR

Genetic studies have indicated that some parasite species formerly thought to be generalists are complexes of morphologically similar species, each appearing to specialize on different host species. Studies on such species are needed to obtain ecological and parasitological data to address whether there are fitness costs in parasitizing atypical host species. We examined whether lungworms from two anuran host species, Lithobates sylvaticus and Lithobates pipiens, differed in measures of infection success in L. pipiens recipient hosts. We also determined if the worms from the two host species were sources of genetically resolvable species of morphologically similar nematodes. Sequences of internal transcribed spacer and lsrDNA regions of adult lungworms from each host species indicated that worms from L. sylvaticus matched Rhabdias bakeri, whereas worms from L. pipiens matched Rhabdias ranae. Our work suggested that these morphologically similar species are distant non-sibling taxa. We infected male and female metamorphs experimentally with lungworm larvae of the two species. We observed higher penetration, higher prevalence and higher mean abundance of adult worms in lungs of male and female metamorphs exposed to R. ranae larvae than in lungs of metamorphs exposed to R. bakeri larvae. Furthermore, metamorphs exposed to R. ranae larvae carried larger adult female worms in their lungs. Some variation in infection measures depended on host sex, but only for one parasite species considered. Overall, the differential establishment and reproductive potential of R. ranae and R. bakeri in L. pipiens suggests co-adaptation.

PMID: 18572173 [PubMed - as supplied by publisher]

(Source: International Journal for Parasitology)

Leishmania major: recruitment of gr-1+ cells into draining lymph nodes during infection is important for early il-12 and ifngamma production.

Experimental Parasitology — Wed, 21 May 2008 04:00:00 +0100

Leishmania major: Recruitment of Gr-1+ cells into draining lymph nodes during infection is important for early IL-12 and IFNgamma production.

Exp Parasitol. 2008 May 21;

Authors: Dos Santos MS, Vaz Cardoso LP, Nascimento GR, Lino RD, Dorta ML, de Oliveira MA, Ribeiro-Dias F

The production of interleukin-12 and interferon-gamma is a key event for controlling leishmaniasis. Here, we tested the hypothesis that after murine infection with Leishmania major, cell migration into draining lymph nodes is crucial for early production of those cytokines. We showed that inflammatory cells carrying the marker of recently migrated cells, the Gr-1 antigen, including polymorphonuclear and mononuclear cells, migrate rapidly into the site of promastigote infection and, subsequently, into draining lymph nodes. Treatment with RB6-8C5 monoclonal antibody reduced local inflammation and migration of Gr-1+ cells into the draining lymph nodes. This reduction was associated with a decrease of interleukin-12 production by draining lymph node cells from BALB/c mice but not C57BL/6 mice. Additionally, interferon-gamma was also reduced in both mouse strains after depletion of Gr-1+ cells, suggesting that these cells are important for early interleukin-12 and interferon-gamma production. Our findings suggest that recently migrated myeloid cells, more than resident cells, are the major source of the early IL-12 production after L. major infection.

PMID: 18501355 [PubMed - as supplied by publisher]

(Source: Experimental Parasitology)

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Trichomonas vaginalis-induced neutrophil apoptosis causes anti-inflammatory cytokine production by human monocyte-derived macrophages

Blackwell Synergy: Parasite Immunology: Table of Contents — Tue, 20 May 2008 20:08:21 +0100

Parasite Immunology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. SUMMARY Neutrophils are the predominant inflammatory cells found in the vaginal discharge of patients with a Trichomonas vaginalis infection. Neutrophils have a shorter life span than other leucocytes. Our previous study indicated that live T. vaginalis ... (Source: Blackwell Synergy: Parasite Immunology: Table of Contents)

Preface.

Advances in Parasitology — Tue, 20 May 2008 16:34:15 +0100

Preface.

Adv Parasitol. 2008;66:ix-x

Authors: Rollinson D, Hay SI

PMID: 18486686 [PubMed - in process]

(Source: Advances in Parasitology)

Obituary.

Advances in Parasitology — Tue, 20 May 2008 16:34:15 +0100

Obituary.

Adv Parasitol. 2008;66:xi-xv

Authors: Baker J

PMID: 18486687 [PubMed - in process]

(Source: Advances in Parasitology)

Chapter 1 strain theory of malaria the first 50 years.

Advances in Parasitology — Tue, 20 May 2008 16:34:15 +0100

Chapter 1 strain theory of malaria the first 50 years.

Adv Parasitol. 2008;66:1-46

Authors: McKenzie FE, Smith DL, O'Meara WP, Riley EM

From the 1920s to the 1970s, a large body of principles and evidence accumulated about the existence and character of 'strains' among the Plasmodium species responsible for human malaria. An extensive research literature examined the degree to which strains were autonomous, stable biological entities, distinguishable by clinical, epidemiological or other features, and how this knowledge could be used to benefit medical and public health practice. Strain theory in this era was based largely on parasite phenotypes related to clinical virulence, reactions to anti-malarial drugs, infectivity to mosquitoes, antigenic properties and host immunity, latency and relapse. Here we review the search for a definition of 'strain', suggest how the data and discussion shaped current understandings of many aspects of malaria and sketch a number of specific connections with perspectives from the past 30 years.

PMID: 18486688 [PubMed - in process]

(Source: Advances in Parasitology)

Chapter 2 advances and trends in the molecular systematics of anisakid nematodes, with implications for their evolutionary ecology and host-parasite co-evolutionary processes.

Advances in Parasitology — Tue, 20 May 2008 16:34:15 +0100

Chapter 2 Advances and Trends in the Molecular Systematics of Anisakid Nematodes, with Implications for their Evolutionary Ecology and Host-Parasite Co-evolutionary Processes.

Adv Parasitol. 2008;66:47-148

Authors: Mattiucci S, Nascetti G

The application of molecular systematics to the anisakid nematodes of the genera Anisakis, Pseudoterranova and Contracaecum, parasites of aquatic organisms, over the last two decades, has advanced the understanding of their systematics, taxonomy, ecology and phylogeny substantially. Here the results of this effort on this group of species from the early genetic works to the current status of their revised taxonomy, ecology and evolutionary aspects are reviewed for each of three parasitic groups. It has been shown that many anisakid morphospecies of Anisakis, Contracaecum and Pseudoterranova include a certain number of sibling species. Molecular genetic markers provided a rapid, precise means to screen and identify several species that serve as definitive and intermediate and or/paratenic hosts of the so far genetically characterized species. Patterns of differential distribution of anisakid nematodes in various definitive and intermediate hosts are presented. Differences in the life history of related species can be due both to differential host-parasite co-adaptation and co-evolution, and/or to interspecific competition, that can reduce the range of potential hosts in sympatric conditions. Phylogenetic hypotheses attempted for anisakid nematodes and the possible evolutionary scenarios that have been proposed inferred from molecular data, also with respect to the phylogeny of their hosts are presented for the parasite-host associations Anisakis-cetaceans and Contracaecum-pinnipeds, showing that codivergence and host-switching events could have accompanied the evolution of these groups of parasites. Finally, examples in which anisakid nematodes recognized genetically at the species level in definitive and intermediate/paratenic hosts from various geographical areas of the Boreal and Austral regions and their infection levels have been used as biological indicators of fish stocks and food-web integrity in areas at high versus low levels of habitat disturbance (pollution, overfishing, by-catch) are presented.

PMID: 18486689 [PubMed - in process]

(Source: Advances in Parasitology)

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Chapter 3 atopic disorders and parasitic infections.

Advances in Parasitology — Tue, 20 May 2008 16:34:15 +0100

Chapter 3 atopic disorders and parasitic infections.

Adv Parasitol. 2008;66:149-91

Authors: Reddy A, Fried B

This chapter examines the relationship between atopic disorders and parasitic infections. Atopy is an exaggerated IgE-mediated Type-1 immune response in predisposed individuals. Conflicting information exists in regard to the relationship of parasitic infections and the classic allergic diseases, that is, atopic dermatitis, allergic rhinitis and asthma. Attention is paid to the explanations for these discrepancies in the literature found within both human and animal studies on atopy with particular emphasis on helminthic infections. The factors that cause only a proportion of atopic individuals to develop clinical disease have not been defined although helminths confer protection in many studies examined. Early childhood infections help induce a Th1-biased immunity and prevent the induction of the Th2 system that causes atopy. Acute parasitic infections may increase manifestations of allergy, whereas chronic infections with parasites decrease atopic predisposition. Nonetheless, a causal association between geohelminth infection and atopic disorders has not been established. Some helminthic substances, especially the cytokines, have respiratory and anti-allergic effects, and may therefore become useful as therapeutic modalities for many atopic and allergic disorders.

PMID: 18486690 [PubMed - in process]

(Source: Advances in Parasitology)

Chapter 4 heartworm disease in animals and humans.

Advances in Parasitology — Tue, 20 May 2008 16:34:15 +0100

Chapter 4 heartworm disease in animals and humans.

Adv Parasitol. 2008;66:193-285

Authors: McCall JW, Genchi C, Kramer LH, Guerrero J, Venco L

Heartworm disease due to Dirofilaria immitis continues to cause severe disease and even death in dogs and other animals in many parts of the world, even though safe, highly effective and convenient preventatives have been available for the past two decades. Moreover, the parasite and vector mosquitoes continue to spread into areas where they have not been reported previously. Heartworm societies have been established in the USA and Japan and the First European Dirofilaria Days (FEDD) Conference was held in Zagreb, Croatia, in February of 2007. These organizations promote awareness, encourage research and provide updated guidelines for the diagnosis, treatment and prevention of heartworm disease. The chapter begins with a review of the biology and life cycle of the parasite. It continues with the prevalence and distribution of the disease in domestic and wild animals, with emphasis on more recent data on the spreading of the disease and the use of molecular biology techniques in vector studies. The section on pathogenesis and immunology also includes a discussion of the current knowledge of the potential role of the Wolbachia endosymbiont in inflammatory and immune responses to D. immitis infection, diagnostic use of specific immune responses to the bacteria, immunomodulatory activity and antibiotic treatment of infected animals. Canine, feline and ferret heartworm disease are updated with regard to the clinical presentation, diagnosis, prevention, therapy and management of the disease, with special emphasis on the recently described Heartworm Associated Respiratory Disease (HARD) Syndrome in cats. The section devoted to heartworm infection in humans also includes notes on other epizootic filariae, particularly D. repens in humans in Europe. The chapter concludes with a discussion on emerging strategies in heartworm treatment and control, highlighting the potential role of tetracycline antibiotics in adulticidal therapy.

PMID: 18486691 [PubMed - in process]

(Source: Advances in Parasitology)

Selenium supplementation enhances the protective response to toxocara canis larvae in mice

Blackwell Synergy: Parasite Immunology: Table of Contents — Thu, 15 May 2008 18:42:34 +0100

Parasite Immunology, Volume 0, Issue 0, Page ???, OnlineEarly Articles. SUMMARY The effect of oral and intraperitoneal supply of sodium selenite on the immune response to, and the course of T. canis larvae infection in mice were determined. The number of worms in the host tissue was reduced but the migratory route of larvae ... (Source: Blackwell Synergy: Parasite Immunology: Table of Contents)

Multilocus genotyping of giardia duodenalis reveals striking differences between assemblages a and b.

International Journal for Parasitology — Thu, 15 May 2008 04:00:00 +0100

Multilocus genotyping of Giardia duodenalis reveals striking differences between assemblages A and B.

Int J Parasitol. 2008 May 15;

Authors: Cacciò SM, Beck R, Lalle M, Marinculic A, Pozio E

Giardia duodenalis is a widespread parasite of mammalian species, including humans. Due to its invariant morphology, investigations of aspects such as host specificity and transmission patterns require the direct genetic characterisation of parasites from faecal samples. We performed a sequence analysis of four genes (ssrRNA, beta-giardin, glutamate dehydrogenase and triose phosphate isomerase) of 61 human isolates and 29 animal isolates. The results showed that multilocus genotypes (MLGs) can be readily defined for G. duodenalis isolates of assemblage A but not for assemblage B. Indeed, for assemblage A isolates, there was no evidence of intra-isolate sequence heterogeneity, and congruent genotyping results were obtained at the four genetic loci investigated. Sequence comparison and phylogenetic analysis showed that human-derived and animal-derived MLGs are different, and further indicated the presence of a new sub-assemblage (referred to as "AIII"), which was found exclusively in wild hoofed animals. On the other hand, there were variable levels of intra-isolate sequence heterogeneity (i.e., the presence of two overlapping nucleotide peaks at specific positions in the chromatograms, or "heterogeneous templates") in assemblage B isolates from humans and animals, and this prevented the unambiguous identification of MLGs. Furthermore, in five human isolates and one non-human primate isolate, the assignment to assemblage B was problematic, given that one of the four markers supported an assignment to assemblage A. These findings raise concerns about the interpretation of genotyping data based on single markers, and indicate the need to understand the mechanisms that are responsible for the differences between G. duodenalis assemblages A and B.

PMID: 18571176 [PubMed - as supplied by publisher]

(Source: International Journal for Parasitology)