Trichodina heterodentata (Ciliophora: Trichodinidae): a new parasite for Piaractus mesopotamicus (Pisces: Characidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Trichodina colisae (Ciliophora: Trichodinidae): new parasite records for two freshwater fish species farmed in Brazil

Tricodinídeos são protozoários ciliados móveis com ampla distribuição mundial; são considerados um dos agentes parasitários que mais acometem peixes cultivados. No Brasil, a maioria dos tricodinídeos que parasitam importantes espécies de peixes cultivados são desconhecidos, o que requer mais estudos taxonômicos com esse grupo de parasitos. Este estudo caracteriza morfologicamente Trichodina colisae Asmat & Sultana, 2005 de pacu (Piaractus mesopotamicus) e do híbrido patinga (P. mesopotamicus × P. brachypomus) cultivados, respectivamente, no Centro-Oeste e Sudeste do Brasil. Foram feitas montagens a fresco do raspado de muco da pele, nadadeiras e brânquias, fixados com metanol e, posteriormente, impregnados com nitrato de prata e coradas com Giemsa para avaliação em microscopia óptica. O presente estudo relata não só a segunda ocorrência de T. colisae no mundo, mas também a primeira ocorrência na América do Sul.

MYZOBDELLA PLATENSIS (HIRUNDINIDA: PISCICOLIDAE) IS TRUE PARASITE of BLUE CRABS (CRUSTACEA: PORTUNIDAE)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Pterygodermatites (Multipectines) pluripectinata n. sp. (Spirurida: Rictulariidae), a nematode parasite of the crab-eating fox Cerdocyon thous (Linnaeus, 1766) from Caatinga shrubland, Brazil

In a parasitological survey of free-ranging Cerdocyon thous (Carnivora: Canidae) from Brazilian Caatinga shrubland, a new species of Pterygodermatites (Multipectines) was recovered from the small intestine of this host. Morphological analysis showed that P. (Multipectines) pluripectinata n. sp. is distinguished from all other congeneric species mainly by the numerous plate-like projections and male caudal morphology and spicular length. There are few records on the occurrence of this genus in Neotropical regions.

Relacionamento de diferentes domínios da atividade física habitual com indicadores de risco cardiovascular em adultos jovens do sexo masculino

Objectives: To analyze different physical activities domains in healthy adults and correlate with cardiovascular risk factors. Methods: The sample was composed by 32 Physical Education undergraduate students, with mean age of 22.6 years old. Adiposity was assessed by waist circumference (WC), body mass index (BMI) and bioelectrical impedance. Additionally, fast glucose (10-12 hours), systolic (SBP) and diastolic (DBP) blood pressure were assessed. Physical activity level was assessed by questionnaire (Baecke et al., 1982). Results: sports activities and leisure time were not related with cardiovascular risk factors. However, job activities were negatively related with %BF, SBP and DBP. Conclusion: Different physical activity domains should be considered when analyzing its associations with health indicators.

Experimental infection with Leishmania chagasi in immunosuppressed Balb/c mice: cytokines and parasite burdens

The immune response in leishmaniasis may result in a polarization of the T lymphocyte subpopulation, altering cell phenotype and resulting in immune protection or disease exacerbation. Leishmania may persist in the body either during asymptomatic infections or after treatment, which represents high risk under immunosuppression. The objective of this study was to evaluate the effect of infection with immunosuppression by dexamethasone associated with pentoxifylline on animal weight, spleen weight, spleen and hepatic parasitic load and immunopathology, as well as the IFN-gamma and IL-10 production in spleen cell culture of Balb/c mice infected with Leishmania chagasi. The infection did not cause body weight gain in animals, but both the weight and size of the spleen were increased. The immunosuppression using dexamethasone associated with pentoxifylline affected body weight gain and spleen weight and size in both infected and non-infected animals. The immunosuppression did not significantly alter the course of the splenic or hepatic parasite burden. Dexamethasone and pentoxifylline significantly affected cytokine production, but did not influence the Th1/Th2 ratio in infected animals.

Experimental infection of Leishmania chagasi in immunosuppressed balb/c mice: cellular immune response and parasite burden

The immune response to leishmaniasis can result in a polarization of a subpopulation of T lymphocytes, which leads to a different cell phenotype and results in immune protection or exacerbation of the disease. Leishmanias persist in the body both in asymptomatic infections and after treatment, representing risks in terms of immunosuppression. The objective of this study was to evaluate the effects of infection and immunosuppression by dexamethasone associated with pentoxifylline on animal weight, spleen weight, the parasitic load in the spleen and liver, as well as the production of IFN-gamma and IL-10 in spleen cell culture of Balb/c mice infected with Leishmania chagasi. The infection did not alter animal weight gain, but spleen weight and size increased. The immunosuppression, induced by dexamethasone associated with pentoxifylline, affected animal weight gain and weight and size of the spleen (in infected and not infected animals). The immunosuppression did not significantly alter the course of the parasite burden in the spleen and liver. Dexamethasone and pentoxifylline affected the studied cytokine production, but not influenced on Th1/Th2 response in infected animals.

Toxoplasma gondii: host-parasite interaction and behavior manipulation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of TNF-alpha, IL-4, and IL-10 and parasite density in spleen and liver of L. (L.) chagasi naturally infected dogs

Dogs are the main domestic reservoirs of L. (L.) chagasi. Once in the vertebrate host, the parasite can cause visceral leishmaniasis, which can also be transmitted to humans. Cytokines are key elements of the host immune response against Leishmania spp. To investigate whether tumor necrosis factor (TNF)-alpha, interleukin (IL)-4 and IL-10 are associated with pattern infection in dogs, these cytokines were quantified in the spleen and liver of dogs naturally infected with L. (L.) chagasi, with or without clinical manifestations, and their levels were correlated with the parasite load verified in these organs. A total of 40 adult dogs naturally infected with L. (L.) chagasi were assessed, together with 12 uninfected control dogs. Samples from spleen and liver were used to determine the cytokine levels by capture ELISA and for quantifying parasite load by real-time PCR. Statistical analysis was performed using the minimum Chi square method and group means were compared using the Tukey test. TNF-alpha, IL-4 and IL-10 levels in infected dogs were higher than in control groups; the liver was the main cytokine-producing organ during infection. The level of splenic TNF-alpha showed correlation with parasite load and may represent an important marker for infection process evolution, with the participation of IL-10. These results may contribute to a clearer understanding of the immune response in dogs infected with L. (L.) chagasi, which may lead to the development of prophylactic or preventive measures for these animals.

Relationship of abomasal histology and parasite-specific immunoglobulin A with the resistance to Haemonchus contortus infection in three breeds of sheep

This study was carried out to evaluate the relationship of abomasal inflammatory cells and parasite-specific immunoglobulin A (IgA) in mucus, with the resistance to Haemonchus contortus infection in three breeds of sheep naturally infected with gastrointestinal nematodes. The breeds were the native Santa Ines sheep, and the European Suffolk and Ile de France breeds. Mast cells, eosinophils and globule leucocytes were enumerated in abomasal mucosa. Eosinophils within the sub-mucosa also were counted separately. Histamine concentration was estimated in abomasal tissue samples. Enzyme-linked immunosorbent assay was carried out in mucus samples to determine the level of IgA anti-H. contortus third and fifth instar. There were no significant differences among group means of these variables (P > 0.05). The correlation coefficients between fecal egg counts (FEC) x mast cells (r = -0.490; P < 0.05) and FEC x eosinophils in sub-mucosa (r = -0.714; P < 0.01) was significant in the Santa Ines sheep. In the Ile de France group, the correlation coefficients between globule leucocytes x FEC (r = -0.879; P < 0.001) and histamine x worm burden (r = -0.833; P < 0.01) were also significant. In the Santa Ines and Ile de France sheep, correlation coefficients between IgA anti-L3 x worm burden and IgA anti-L3 x FEC were negative. In general, inflammatory cells and IgA-parasite-specific in abomasum were inversely associated with H. contortus worm burden and FEC indicating that they may impair parasite development or fecundity in the three breeds of sheep. However, similar mean values of inflammatory cells and IgA were found in the resistant (Santa Ines) and in the susceptible (Suffolk and Ile de France) breeds of sheep. The enumeration of cells by histological assessment does not provide information on their functional activity, which may be different among breeds. Thus, the effect of breed on the functional activity of these and other inflammatory cells is an important area for further study. (c) 2004 Elsevier B.V. All rights reserved.

In vivo uptake of a haem analogue Zn protoporphyrin IX by the human malaria parasite P. falciparum-infected red blood cells

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Automated Nuclear Analysis of Leishmania major Telomeric Clusters Reveals Changes in Their Organization during the Parasite's Life Cycle

Parasite virulence genes are usually associated with telomeres. The clustering of the telomeres, together with their particular spatial distribution in the nucleus of human parasites such as Plasmodium falciparum and Trypanosoma brucei, has been suggested to play a role in facilitating ectopic recombination and in the emergence of new antigenic variants. Leishmania parasites, as well as other trypanosomes, have unusual gene expression characteristics, such as polycistronic and constitutive transcription of protein-coding genes. Leishmania subtelomeric regions are even more unique because unlike these regions in other trypanosomes they are devoid of virulence genes. Given these peculiarities of Leishmania, we sought to investigate how telomeres are organized in the nucleus of Leishmania major parasites at both the human and insect stages of their life cycle. We developed a new automated and precise method for identifying telomere position in the three-dimensional space of the nucleus, and we found that the telomeres are organized in clusters present in similar numbers in both the human and insect stages. While the number of clusters remained the same, their distribution differed between the two stages. The telomeric clusters were found more concentrated near the center of the nucleus in the human stage than in the insect stage suggesting reorganization during the parasite's differentiation process between the two hosts. These data provide the first 3D analysis of Leishmania telomere organization. The possible biological implications of these findings are discussed.

Comparison of naturally acquired parasite burdens among Florida Native, Rambouillet and crossbreed ewes

The response to natural infection by gastrointestinal nematodes was evaluated in three groups of lambing mature ewes: 16 Florida Native; 21 Rambouillet; and 18 1/2 Florida Native x 1/2 Rambouillet (F1 generation). Fecal egg counts (FEC),packed cell volume (PCV) and plasma protein levels were determined periodically through a one-year period. The highest FEC was recorded in Rambouillet ewes, with most of the means higher than 1000 eggs per gram (EPG). Florida Native and Fl ewes showed similar trends in FEC, with most of the means below 500 EPG. The highest mean PCV values were recorded in Florida Native ewes, followed in decreasing order by Fl and Rambouillet ewes. Fl ewes showed the lowest plasma protein levels and Florida Natives the highest. Fecal cultures revealed the highest percentages of Haemonchus larvae in Rambouillet ewes (>64%) and the lowest percentages in Florida Native ewes. Florida Native and Fl ewes were more resistant to gastrointestinal nematode infections than were Rambouillet ewes. High negative correlation coefficients between FEC x PCV and FEC x plasma protein levels coincided with peaks in mean FEC of Rambouillet (May and July), Florida Native and Fl ewes (October). This study showed that crossbreeding Rambouillet and Florida Native sheep resulted in the production of Fl ewes resistant against gastrointestinal nematode infections. (C) 1999 Elsevier B.V. B.V. All rights reserved.

Proleptus acutus Dujardin, 1845 (Nematoda, Physalopteridae) parasite of rays Zapteryx brevirostris Müller & Henle, 1841 (Rhinobatiformes, Rhinobatidae) in Brazil

Relata-se a ocorrência de Proleptus acutus Dujardin, 1845 (Nematoda, Physalopteridae) parasitando Zapteryx brevirostris Müller & Henle, 1841 (Rhinobatiformes, Rhinobatidae) em Ubatuba, estado de São Paulo, Brasil. Vinte raias foram analisadas e P. acutus foi encontrado no estômago e intestinos de 14 (70%) animais. Este é o primeiro relato da ocorrência dessa espécie de nematóide em Z. brevirostris no Brasil.

Phylogeny, ultrastructure, histopathology and prevalence of Myxobolus oliveirai sp. nov., a parasite of Brycon hilarii (Characidae) in the Pantanal wetland, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)