Alexandre do Rosário Casseb

Seroprevalence of flaviviruses antibodies in water buffaloes (Bubalus bubalis)in Brazilian Amazon

BackgroundThe state of Pará encompasses 26% of Brazilian Amazon where an enormous diversity of arboviruses has been found. This study aimed to assess the prevalence and distribution of hemagglutination-inhibition antibodies against antigens of six Flavivirus (yellow fever virus, Ilheus virus, Saint Louis encephalitis virus, Cacipacore virus, Bussuquara virus and Rocio virus) in water buffaloes in Pará state, Brazil. The prevalence of antibodies in these farm animals is important to determine the circulating arboviruses.FindingsAll investigated arboviruses were detected in the species studied and our results indicate that water buffaloes are susceptible to Flavivirus infection. Furthermore, there is solid evidence of active circulation of these viruses in the Brazilian Amazon.ConclusionsWater buffaloes showed higher prevalence of heterotypic antibody reactions and we hypothesized that they can serve as sentinels to detect the movement of such arboviruses in the Brazilian Amazon.

Changuinola Virus Serogroup, New Genomes within the Genus Orbivirus (Family Reoviridae) Isolated in the Brazilian Amazon Region

ABSTRACT We report here the first complete genome sequence of a Changuinola virus (CGLV) serotype Irituia virus (BE AN 28873) isolated from a wild rodent (Oryzomys goeldi) in the municipality of Ipixuna, State of Pará, northern Brazil. All genome segments showed similarity with those belonging to members of the genus Orbivirus, family Reoviridae.

Clinical and serological tests for arboviruses in free-living domestic pigeons (Columba livia)

BACKGROUND In this study, we evaluated the role of free-living domestic pigeons (Columba livia) as a reservoir of arboviruses in the city of Belém, state of Pará, Brazil. We investigated the presence of antibodies against the most prevalent arboviruses. OBJECTIVES This study was aimed at evaluating some clinical and physical parameters of domestic pigeons, including the presence of antibodies to Amazon-endemic arboviruses. METHODS Eighty-five healthy pigeons were captured in Mangal das Garças Park, in Belém, and were bled. Upon capture, the birds were subjected to a clinical examination in search of alterations that could indicate the presence of arboviruses. Blood samples were converted to serum and tested using the haemagglutination inhibition (HI) technique with a panel of 19 antigens of arboviruses circulating in the Amazon. The confirmation assay for the positive reactions to the viral species tested by HI was a neutralisation test in new-born Swiss albino mice (Mus musculus) [mouse neutralisation test (MNT)]. FINDINGS A total of 10 (11.8%) serum samples tested positive for antiflavivirus antibodies by HI. All the samples positive for the HI test were subjected to MNT for detection of viruses and yielded negative results (logarithmic neutralisation index < 1.7). MAIN CONCLUSION The results represent the first serological detection of antiarbovirus antibodies in domestic pigeons as potential hosts of arboviruses in Brazil. The detection of haemagglutination-inhibiting antibodies against genus Flavivirus indicated that there was recent contact between the analysed domestic pigeons and these arboviruses. Further studies are needed to evaluate the role of free-living pigeons in the maintenance cycle and spread of arboviruses in the Amazon.

Prevalence of antibodies to equine alphaviruses in the State of Pará, Brazil

The State of Para comprises 26% of Brazilian Amazon region, where a large diversity of arboviruses has been described. This study sought to assess the prevalence and distribution of hemagglutination inhibition (HI) antibodies against antigens of four alphaviruses (Togaviridae: Alphavirus ) from the species: Eastern equine encephalitis (EEEV), Western equine encephalitis (WEEV), Mayaro virus (MAYV), and Mucambo virus (MUCV) in 753 serum samples of horses in Para State, Brazil. All investigated arboviruses were detected and indicate that horses are susceptible to these alphaviruses, and show evidences of their active circulation in farm animals in the Brazilian Amazon.

Diagnosis of arboviruses using indirect sandwich IgG ELISA in horses from the Brazilian Amazon

BackgroundThe Amazon as a whole is the largest reservoir of arboviruses worldwide, while the Brazilian Amazon hosts the largest variety of arboviruses isolated to date. In this study, the results of an indirect sandwich IgG ELISA, standardized for 19 arbovirustypes circulating among horses in Brazilian Amazon, were compared to results of the hemagglutination inhibition test. A screening test assessed the conditional probability distribution and a Pearson linear correlation test determined the correlation strength among the absorbance values recorded for viruses from the same family.FindingsSensitivity varied between 40.85 and 100%; the specificity was low and ranged from 39.71 to 67.0%; and the accuracy varied between 41 and 65.2%. The test developed in this study yielded a large number of serological cross-reactions.ConclusionsThe test can be employed to detect IgG antibodies within one arbovirus family; however, the hemagglutination test or other more specific techniques, such as the serum neutralization test in mice or the plaque-reduction neutralization test, are essential complementary methods for positive cases.

Comparação das técnicas de ELISA indireto e Imunofluorescência indireta na detecção de anticorpos anti-Neospora caninum em búfalas (Bubalus bubalis)

Para comparar dois testes sorologicos na deteccao de anticorpos anti-Neospora caninum em soros sanguineos de bufalas, foram coletados amostras de 288 bufalas entre dois a dez anos de idade. Para identificar a presenca de imunoglobulina G anti-N. caninum utilizou-se a reacao de imunofluorescencia indireta (RIFI), tendo o titulo 200 como ponto de corte, e o Ensaio Imunoenzimatico indireto (ELISA-indireto), considerando-se positiva as amostras que obtiveram razao S/P>0,5. Observaram-se 153 (53,12%) animais soropositivos para N. caninum, atraves da RIFI, enquanto que 50 (17,36%) animais foram reagentes no ELISA. A ocorrencia de anticorpos anti-N. caninum demonstram que o parasito esta circulando entre bufalas criadas no estado do Para, sendo que ambos os teste de RIFI e ELISA podem ser utilizados para diagnosticar imunoglobulinas contra este agente. No entanto observou-se uma fraca correlacao (Kappa=0,36) entre ambos os testes, considerando a RIFI como padrao ouro.

Alphavirus serosurvey in domestic herbivores in Pará State, Brazilian Amazon

This study was partially supported by the National Council for Scientific and Technological Development (CNPq) (grant 301641/2010-2).