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Canine visceral leishmaniasis (CVL) is recognizable by characteristic signs of disease and is highly lethal. The infection, however, may be quite inapparent in some seropositive dogs, and this has raised the polemic question as to whether or not such animals can be a source of infection for Lutzomyia longipalpis, the vector of American visceral leishmaniasis (AVL). In this study we have examined 51 dogs with acute CVL from an AVL area in Pará State, northern Brazil, and compared the parasite density, amastigotes of Leishmania (L.) infantum chagasi, in the skin, lymph node and viscera of symptomatic with that of nine asymptomatic but seropositive dogs (IFAT-IgG). Post-mortem biopsy fragments of these tissues were processed by immunohistochemistry, using a polyclonal antibody against Leishmania sp. The X² and Mann Whitney tests were used to evaluate the means of infected macrophage density (p < 0.05). There was no difference (p > 0.05) in the skin (10.7/mm² x 15.5/mm²) and lymph node (6.3/mm² x 8.3/mm²), between asymptomatic and symptomatic dogs, respectively. It was higher (p < 0.05), however, in the viscera of symptomatic (5.3/mm²) than it was in asymptomatic (1.4/mm²) dogs. These results strongly suggest that asymptomatic or symptomatic L. (L.) i. chagasi-infected dogs can serve as a source of infection, principally considering the highest (p < 0.05) parasite density from skin (10.7/mm² x 15.5/mm²), the place where the vetor L. longipalpis takes its blood meal, compared with those from lymph node (6.3/mm² x 8.3/mm²) and viscera (1.4/mm²x 5.3/mm²).

This was a prospective study carried out during a period over 2 years (May/2006-September/2008) with a cohort of 1,099 individuals of both genders, aged 1 year old and older, from an endemic area of American visceral leishmaniasis (AVL) in Pará state, Brazil. The object was to analyze the prevalence and incidence of human Leishmania (L.) infantum chagasi infection as well as the dynamics evolution of its clinical-immunological profiles prior identified: (1) asymptomatic infection (AI); (2) symptomatic infection (SI = AVL); (3) sub-clinical oligosymptomatic infection (SOI); (4) sub-clinical resistant infection (SRI) and; (5) indeterminate initial infection (III). The infection diagnosis was performed by using both the indirect fluorescent antibody test and leishmanin skin test with amastigotes and promastigotes antigens of L. (L.) i. chagasi, respectively. A total of 187 cases of infection were recorded in the prevalence (17%), 117 in the final incidence (6.9%), and 304 in the accumulated prevalence (26.7%), which provided the following distribution into the clinical-immunological profiles: AI, 51.6%; III, 22.4%; SRI, 20.1%; SOI, 4.3%; and SI (=AVL), 1.6%. The major finding regarding the dynamics evolution of infection was concerned to III profile, from which the cases of infection evolved to either the resistant profiles, SRI (21 cases, 30.8%) and AI (30 cases, 44.1%), or the susceptible SI (=AVL; 1 case, 1.5%); the latter 16 cases remained as III till the end of the study. These results provided the conclusion that this diagnostic approach may be useful for monitoring human L. (L.) i. chagasi infection in endemic area and preventing the high morbidity of severe AVL cases.

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We present here a cross-sectional study analyzing the IgG1 and IgG2 immune responses to natural canine Leishmania (L.) infantum chagasi-infection and their relationships with delayed-type hypersensitivity (DTH) in 50 mongrel dogs with previous positive serodiagnoses (IFAT-IgG) (56% with subclinical status [= apparently healthy] and 44% clinically sick), living in endemic areas for visceral leishmaniasis in the Brazilian Amazon. IgG1 and IgG2 responses were measured using commercial polyclonal antibodies in ELISA, while DTH was elicited by intradermal skin test using cultured promastigotes L. (L.) i. chagasi-antigen. Data analyses used Chi-square and Pearson's r coefficient (95% confidence interval). Regarding DTH and the clinical statuses of dogs, it was noted that 100% of the animals showing positive DTH (n = 8) were from the subclinical group, while 100% showing negative DTH were from the clinically sick group; higher IgG2 than IgG1 responses were observed in both clinical groups. However, when this comparison was made between the subclinical and sick groups, higher IgG1 responses were noted in the dogs from the sick rather than the subclinical group, while no differences were noted between the IgG2 responses in the dogs from both clinical groups. Additionally, we found lower IgG1 responses in dogs from the subclinical group showing positive DTH than in the dogs from the subclinical or sick groups with negative DTH; no differences were found between the IgG2 responses of these two clinical groups. These findings suggest that the IgG1, but not the IgG2, response is associated with susceptibility to canine visceral leishmaniasis (CVL).

Redescriptions are given of the mature oocysts of Eimeria aguti Carini 1935, E. cotiae Carini, 1935 and E. paraensis Carini, 1935 Following the examination of faeces from a single specimen of an agouti, which he referred to as "Cotia vermelha (Aguti aguti)", Carini (1935) described the mature oocysts of what he considered to be three distinct species of Eimeria, and named them E. paraensis, E. cotiae, and E. aguti. Pellérdy (1974) pointed out that the genus "Cotia" does not exist within the Class Mammalia and listed the host of these parasites as Dasyprocta aguti. This was corrected by Levine and Ivens (1990) to Dasyprocta leporina (Linnaeus, 1758), for which D. aguti is now considered to be a synonym (Hussan 1978). The animal was housed in the Parque Zoobotânico of the Museu Emilio Goeldi, in Belém, Pará, North Brazil, and although the exact locality of its origin was not given, it was most likely to have been somewhere in Pará.We have examined the faeces of 10 D. leporina, identified to species by cytogenic analysis, from two different areas of Pará: five of them were passing oocysts of Eimeria species which superficially resembled those described in D. leporina by Carini. In this communication we give re-descriptions of the mature oocysts of E. aguti and those previously described as E. paraensis and E. cotiae (Carini 1935): some endogenous stages, regarded as those of E. cotiae, are described in the ileum. Doubts are raised regarding separation of this parasite and E. paraensis. MATERIALS AND METHODSThe agoutis were captured in fruit and vegetable-baited traps. Eight of the animals were from the municipality of Anajás, Island of Marajó, Pará (0.59 S : 49.57 W) and two from the Island of Caratateua (more popularly known as Outero), municipality of Belém, Pará (1.18 S : 48.28 W): they were maintained, in separate cages, on a diet of mixed fruit and vegetables and given water ad libitum. Faecal samples were obtained daily, lightly triturated in 2% aqueous potassium dichromate solution (K 2 Cr 2 O 7 ), kept at approximately 24ºC as thin layers in loosely covered Petri dishes, and examined for the presence of coccidial oocysts by both direct microscopical examination and the zinc sulphate flotation method (Baker 1969). Positive samples were examined daily to determine the time required for oocyst sporulation.In an attempt to locate the site of development of the parasites in D. leporina, two of the naturally infected animals were sacrificed, and a search made for endogenous stages in both the gall-bladder and intestinal epithelium. The entire alimentary tract was fixed in 10% buffered formalin for subsequent preparation of histological sections of the duodenum, ileum, caecum, and colon. Oocysts and sporocysts were measured using a x 100 neofluar objective and x 10 eyepieces with an ocular micrometer. Photomicrographs were prepared with a Zeiss "Photomicroscope III" and Kodak TMX 100 film. All measurements are given in µm and presented as means, with the range in parentheses, followed by the shape-index (ratio o...

During the Zika virus (ZIKV) outbreak in Brazil (2015–2016), the clinical manifestations associated with its infection were complex and included miscarriage and congenital malformations, not previously described. In this study, we evaluated the prenatal conditions of pregnant female squirrel monkeys (Saimiri collinsi) infected during different gestational thirds (GTs) and assessed all clinical aspects, diagnostic imaging, viremia and the immune response. In our study, 75% of the infected animals in the 1st GT group had significant clinical manifestations, such as miscarriage and prolonged viremia associated with a late immune response. Consequently, their neonates showed fetal neuropathology, such as cerebral hemorrhage, lissencephaly or malformations of the brain grooves, ventriculomegaly, and craniofacial malformations. Thus, our study demonstrated the relevance of pregnant squirrel monkeys as a model for the study of ZIKV infection in neonates due to the broad clinical manifestations presented, including the typical congenital Zika syndrome manifestations described in humans.