Trypanosoma cruzi among wild and domestic mammals in different areas of the Abaetetuba municipality (Pará State, Brazil), an endemic Chagas disease transmission area.

The presence of acute Chagas disease (ACD) due to oral transmission is growing and expanding in several South American countries. Within the Amazon basin, the Abaetetuba municipality has been a site of recurrent cases spanning across distinct landscapes. Because Chagas disease is primarily a zoonotic infection, we compared the enzootic Trypanosoma cruzi transmission cycles in three different environmental areas of Abaetetuba to better understand this new epidemiological situation. Philander opossum was the most abundant mammalian species collected (38% of the collected mammals) with a T. cruzi prevalence of 57%, as determined by hemocultures. Didelphis marsupialis was abundant only in the area with the higher level of environmental disturbance (approximately 42%) and did not yield detectable parasitemia. Despite similarities observed in the composition of the small mammalian fauna and the prevalence of T. cruzi infection among the studied areas, the potential of these hosts to infect vectors differed significantly according to the degree of land use (with prevalences of 5%, 41%, and 64% in areas A3, A1 and A2, respectively). Domestic mammals were also found to be infected, and one canine T. cruzi isolate was obtained. Our data demonstrated that the transmission of T. cruzi in the Amazon basin is far more complex than had been previously taught and showed that the probability of humans and domestic mammals coming into contact with infected bugs can vary dramatically, even within the same municipality. The exposure of dogs to T. cruzi infection (indicated by positive serology) was the common feature among the studied localities, stressing the importance of selecting domestic mammals as sentinels in the identification of T. cruzi transmission hotspots.

Animal infections by vaccinia-like viruses in the state of Rio de Janeiro: an expanding disease / Infecções animais por vírus semelhantes ao vaccínia no estado do Rio de Janeiro: uma doença em expansão

In the present study we investigated the presence of infections by vaccinia-like viruses in dairy cattle from 12 counties in the state of Rio de Janeiro in the last 9 years. Clinical specimens were collected from adult animals with vesicular/pustular lesions mainly in the udder and teats, and from calves with lesions around the nose and mouth. A plaque reduction neutralization test (PRNT) was applied to search for antibodies to Orthopoxvirus; the vesicular/pustular fluids and scabs were examined by PCR, electron microscopy (EM) and by inoculation in VERO cells for virus isolation. Antibodies to Orthopoxvirus were detected in most cases. The PCR test indicated a high nucleotide homology among the isolates and the vaccinia viruses (VACV) used as controls. By EM, typical orthopoxvirus particles were observed in some specimens. The agents isolated in tissue culture were confirmed as vaccinia-like viruses by EM and PCR. The HA gene of the vaccinia-like Cantagalo/IOC virus isolated in our laboratory was sequenced and compared with other vaccinia-like isolates, showing high homology with the original Cantagalo strain, both strains isolated in 1999 from dairy cattle. Antibodies to Orthopoxvirus were detected in one wild rodent (genus Akodon sp.) collected in the northwestern region of the state, indicating the circulation of poxvirus in this area. Nonetheless, PCR applied to tissue samples collected from the wild rodents were negative. Vesicular/pustular lesions in people in close contact with animals have been also recorded. Thus, the vaccinia-like virus infections in cattle and humans in the state seem to be an expanding condition, resulting in economic losses to dairy herds and leading to transient incapacitating human disease. Therefore, a possible immunization of the dairy cattle in the state should be carefully evaluated.

Neste estudo avaliou-se a presença de infecções por vírus semelhantes ao vírus vaccínia (VACV) em gado leiteiro em 12 municípios no estado do Rio de Janeiro, ao longo dos últimos nove anos. Amostras clínicas foram coletadas de animais com vesículas, pústulas e crostas no úbere e tetas, e da região do nariz e da cavidade oral de bezerros. Um teste de neutralização viral por redução de placas foi desenvolvido para investigar a presença de anticorpos contra Orthopoxvirus. Os fluidos de vesículas / pústulas e as crostas foram testadas por PCR, microscopia eletrônica (ME) e por inoculação em células VERO para isolamento viral. Anticorpos contra Orthopoxvirus foram detectados na grande maioria dos animais. O teste de PCR demonstrou homologia entre os vírus isolados e amostras de vírus vaccínia usados como controles. Na ME, partículas típicas de Orthopoxvirus foram observadas em vários espécimes analisados. Os vírus isolados em cultivo celular foram confirmados como Orthopoxvirus por PCR e ME. O gene HA da amostra Cantagalo/IOC isolada em nosso laboratório foi seqüenciado e comparado com outras amostras semelhantes ao vaccínia, mostrando uma alta homologia com a amostra original Cantagalo, tendo sido as duas amostras isoladas em 1999 de gado leiteiro. Anticorpos para Orthopoxvirus foram detectados em um roedor silvestre do gênero Akodon sp. coletado na região noroeste do estado, sugerindo uma circulação de poxvírus na natureza. No entanto, os testes de PCR aplicados a tecidos de roedores silvestres foram negativos. Infecções vesiculares / pustulares em humanos que mantinham contato com os animais afetados também foram relatadas. Assim, infecções por amostras semelhantes ao vírus VACV em bovinos e em humanos parecem em expansão no estado, gerando perdas econômicas em animais e quadros de doença incapacitante temporária em pacientes humanos. Dessa forma, a possibilidade da imunização do gado leiteiro no estado deve ser devidamente avaliada.

Trypanosoma cruzi (Kinetoplastida, Trypanosomatidae) genotypes in neotropical bats in Brazil.

Few studies have been conducted to investigate the role played by the order Chiroptera in the sylvatic transmission cycle of Trypanosoma cruzi or their putative association with the main genotypes of the parasite. Here, the purpose was to enlarge the knowledge of this issue, in this sense, 93 specimens of bats included in 4 families, respectively Molossidae, Noctilionidae, Phyllostomidae and Vespertilionidae collected in distinct regions of Brazil were submitted to fresh blood smears and hemocultures. No patent parasitemia was observed but positive hemocultures by T. cruzi were observed in 14% (13/93) of examined samples. The majority of the parasite isolates were obtained from Phyllostomus hastatus (80%) captured in one same buriti hollow palm tree in the Cerrado region. Multilocus enzyme electrophoresis (MLEE) analyses showed that the genetic distance among these isolates was 0.35, almost the same observed when all the isolates (excluding the reference strains) were analyzed (0.40). No correlation of zymodeme with bat genera, species or geographic region of its origin could be observed, moreover, correlation of zymodeme and genotype of the parasite was not strict. Ten out of 14 T. cruzi isolates obtained from bats corresponded to the TCII genotype. Chiropterans with TCI, TCII/TCIII mixed infection as well as Trypanosoma rangeli in single or mixed infections were observed. These results show that bats may harbor and are probably important maintainers of the main genotypes (TCI, TCII, TCIII/Z3) of T. cruzi. These results support the absence of an association of TCII with any mammal order and show that bats, mainly P. hastatus, may act as amplifier hosts of TCII subpopulations of T. cruzi.