A Saint Louis encephalitis and Rocio virus serosurvey in Brazilian horses.

INTRODUCTION: Arboviruses are an important public health problem in Brazil, in especially flaviviruses, including the Saint Louis encephalitis virus (SLEV) and the Rocio virus (ROCV), are especially problematic. These viruses are transmitted to humans or other vertebrates through arthropod bites and may cause diseases with clinical manifestations that range from asymptomatic infection, viral hemorrhagic fever to encephalitis. METHODS: A serological survey of horses from various regions of Brazil using an enzyme-linked immunosorbent assay (ELISA) with recombinant SLEV domain III peptides and ROCV E protein as antigens. RESULTS: Overall, 415 (55.1%) of the 753 horses that were screened were seropositive for flavivirus and, among them, monotypic reactions were observed to SLEV in 93 (12.3%) and to ROCV in 46 (6.1%). These results suggested that these viruses, or other closely related viruses, are infecting horses in Brazil. However, none of the studied horses presented central nervous system infection symptoms. CONCLUSIONS: Our results suggest that SLEV and ROCV previously circulated among horses in northeast, west-central and southeast Brazil.

Infection with Saint Louis encephalitis virus in the city of Ribeirao Preto, Brazil: report of one case.

Saint Louis encephalitis virus (SLEV) is a mosquito-borne flavivirus from the Americas. In this report we describe aspects of the laboratory diagnosis of a patient with an acute febrile illness induced by SLEV that was initially diagnosed as dengue by positive IgM-ELISA. Infection with this virus is probably not rare in Brazil, but cases remain undiagnosed. It is necessary to improve the surveillance system, including laboratories, for the diagnosis of SLEV in Brazil.

A Saint Louis encephalitis and Rocio virus serosurvey in Brazilian horses

Introduction Arboviruses are an important public health problem in Brazil, in especially flaviviruses, including the Saint Louis encephalitis virus (SLEV) and the Rocio virus (ROCV), are especially problematic. These viruses are transmitted to humans or other vertebrates through arthropod bites and may cause diseases with clinical manifestations that range from asymptomatic infection, viral hemorrhagic fever to encephalitis. Methods A serological survey of horses from various regions of Brazil using an enzyme-linked immunosorbent assay (ELISA) with recombinant SLEV domain III peptides and ROCV E protein as antigens. Results Overall, 415 (55.1%) of the 753 horses that were screened were seropositive for flavivirus and, among them, monotypic reactions were observed to SLEV in 93 (12.3%) and to ROCV in 46 (6.1%). These results suggested that these viruses, or other closely related viruses, are infecting horses in Brazil. However, none of the studied horses presented central nervous system infection symptoms. Conclusions Our results suggest that SLEV and ROCV previously circulated among horses in northeast, west-central and southeast Brazil. .

Serologic survey of West Nile virus in horses from Central-West, Northeast and Southeast Brazil.

Since the emergence of West Nile virus (WNV) in North America in 1999, there have been several reports of WNV activity in Central and South American countries. To detect WNV in Brazil, we performed a serological survey of horses from different regions of Brazil using recombinant peptides from domain III of WNV. Positive samples were validated with the neutralisation test. Our results showed that of 79 ELISA-positive horses, nine expressed WNV-specific neutralising antibodies. Eight of the infected horses were from the state of Mato Grosso do Sul and one was from the state of Paraíba. Our results provide additional evidence for the emergence of WNV in Brazil and for its circulation in multiple regions of the country.

Production and diagnostic application of recombinant domain III of West Nile envelope protein in Brazil.

INTRODUCTION: West Nile virus (WNV) is a flavivirus with a natural cycle involving mosquitoes and birds. Over the last 11 years, WNV has spread throughout the Americas with the imminent risk of its introduction in Brazil. METHODS: Envelope protein domain III of WNV (rDIII) was bacterially expressed and purified. An enzyme-linked immunosorbent assay with WNV rDIII antigen was standardized against mouse immune fluids (MIAFs) of different flavivirus. RESULTS: WNV rDIII reacted strongly with St. Louis encephalitis virus (SLEV) MIAF but not with other flaviviruses. CONCLUSIONS: This antigen may be a potentially useful tool for serologic diagnosis and may contribute in future epidemiological surveillance of WNV infections in Brazil.

Production and diagnostic application of recombinant domain III of West Nile envelope protein in Brazil

INTRODUCTION: West Nile virus (WNV) is a flavivirus with a natural cycle involving mosquitoes and birds. Over the last 11 years, WNV has spread throughout the Americas with the imminent risk of its introduction in Brazil. METHODS: Envelope protein domain III of WNV (rDIII) was bacterially expressed and purified. An enzyme-linked immunosorbent assay with WNV rDIII antigen was standardized against mouse immune fluids (MIAFs) of different flavivirus. RESULTS: WNV rDIII reacted strongly with St. Louis encephalitis virus (SLEV) MIAF but not with other flaviviruses. CONCLUSIONS: This antigen may be a potentially useful tool for serologic diagnosis and may contribute in future epidemiological surveillance of WNV infections in Brazil.

An experimental model of meningoencephalomyelitis by Rocio flavivirus in BALB/c mice: inflammatory response, cytokine production, and histopathology.

Rocio virus (ROCV) is a flavivirus, probably transmitted by Culex mosquitoes and maintained in nature as a zoonosis of wild birds. Rocio virus caused a human epidemic of severe encephalitis that lasted from 1973 to 1980 in the Ribeira valley, in the southeastern coast of Brazil. After this outbreak, serologic evidence of ROCV circulation has been reported and public health authorities are concerned about a return of ROCV outbreaks in Brazil. We show here a study on the pathogenesis and the physiopathology of ROCV disease in the central nervous system of a Balb/C young adult mice experimental model. The animals were intraperitoneally infected by ROCV and followed from 0 to 9 days after infection, when all of them died. Nervous tissue samples were collected from infected animals for immunohistochemistry and molecular biology analysis. We observed the virus in the central nervous system, the inflammatory changes induced by Th1 and Th2 cytokines, and the final irreversible damage of nervous tissues by neuronal degeneration and apoptosis. These findings can help to better understand the pathogenesis and physiopathology of the human meningoencephalomyelitis by ROCV and other flaviviruses.

Domain III peptides from flavivirus envelope protein are useful antigens for serologic diagnosis and targets for immunization.

The Flavivirus genus of the Flaviviridae family includes 70 enveloped single-stranded-RNA positive-sense viruses transmitted by arthropods. Among these viruses, there are a relevant number of human pathogens including the mosquito-borne dengue virus (DENV), yellow fever virus (YFV), Japanese encephalitis virus (JEV) and West Nile virus (WNV), as well as tick-borne viruses such as tick-borne encephalitis virus (TBEV), Langat virus (LGTV) and Omsk hemorrhagic fever (OHFV). The flavivirus envelope (E) protein is a dominant antigen inducing immunologic responses in infected hosts and eliciting virus-neutralizing antibodies. The domain III (DIII) of E protein contains a panel of important epitopes that are recognized by virus-neutralizing monoclonal antibodies. Peptides of the DIII have been used with promising results as antigens for flavivirus serologic diagnosis and as targets for immunization against these viruses. We review here some important aspects of the molecular structure of the DIII as well as its use as antigens for serologic diagnosis and immunization in animal models.

[An overview of hepatitis B in Brazil and in the state of Santa Catarina]. / Panorama da hepatite B no Brasil e no Estado de Santa Catarina.

OBJECTIVE: To provide an overview of hepatitis B infection in Brazil overall, in the South of Brazil, and in the state of Santa Catarina (in southeastern Brazil) for the period of 1996 through 2002, taking into consideration such epidemiological aspects as age and sex. SOURCE OF DATA: Data were obtained through a literature review and by consulting with Brazil's National Health Foundation and with Santa Catarina's Department of Epidemiological Surveillance. RESULTS: In Brazil, from 1996 through 2000, hepatitis B was the second most prevalent type of viral hepatitis (25%), with hepatitis A leading in terms of the proportion of cases (43%). In Santa Catarina there was a predominance of hepatitis B in relation to other types of hepatitis from 1997 through 2001. In both Brazil and Santa Catarina there was a larger number of cases among males than among females. In terms of age, the highest incidence was found among those 20 to 49 years old in Santa Catarina and among those over 30 for Brazil overall. The South of Brazil was the country's region with the highest incidence of hepatitis B from 1997 through 1999. In Santa Catarina the largest number of cases from 1996 through 2002 occurred in the southern part of the state, followed by the northeastern and far western sections of the state. CONCLUSIONS: The number of cases of hepatitis B is still growing in Brazil, and it is important to consider that underreporting may have affected the results described in this study. Throughout Brazil, vaccination should be extended to include adolescents in regions that have a moderate to high incidence of hepatitis B.

Diagnóstico laboratorial do líquido amniótico / Laboratory diagnosis of amniotic fluid

O presente trabalho tem como objetivos a definiçäo e a fisiologia do líquido amniótico, ressaltando aspectos citológicos e principais técnicas para diagnóstico laboratorial das patologias mais freqüentes. A metodologia utilizada foi a revisäo bibliográfica atualizada relacionando os aspectos citológicos com a idade gestacional e técnicas laboratoriais para diagnóstico das principais patologias em que säo observadas alterações do líquido amniótico, concluindo-se que este é um importante componente do ambiente intra-uterino. Sua produçäo e absorçäo dependem de uma série de mecanismos interdependentes entre o feto, a placenta, as membranas e o organismo materno. Atualmente este fluido pode fornecer inúmeras informações sobre a saúde fetal, realizando-se diversas técnicas, entre elas a amniocentese e a dosagem de alfafetoproteína, que pode detectar defeitos do tubo neural e trissomia do cromossomo 21. A análise do líquido amniótico reforça a importância da realizaçäo adequada de um pré-natal, sendo importante relacionar os resultados laboratoriais com a clínica

Panorama da hepatite B no Brasil e no Estado de Santa Catarina / An overview of hepatitis B in Brazil and in the state of Santa Catarina

OBJETIVO: Traçar um panorama da infecção por hepatite B no Brasil, na Região Sul e no Estado de Santa Catarina para o período de 1996 a 2002, considerando aspectos epidemiológicos como faixa etária. FONTE DOS DADOS:Os dados foram obtidos a partir de levantamento bibliográfico e consulta à Secretaria de Vigilância Epidemiológica do Estado de Santa Catarina e à Fundação Nacional de Saúde (FUNASA). RESULTADOS: No Brasil, de 1996 a 2000, a hepatite B foi o segundo tipo de hepatite viral mais prevalente (25%), tendo sido a hepatite A líder em casos (43%). Em Santa Catarina houve predomínio de hepatite B em relação às outras hepatites de 1997 a 2001. O sexo mais atingido pela hepatite B foi o masculino e a maior incidência de hepatite B foi observada na faixa etária dos 20 aos 49 anos para Santa Catarina e acima dos 30 anos para o Brasil. O Sul foi a região brasileira que apresentou a maior incidência de hepatite B no período de 1997 a 1999. Em Santa Catarina, o maior número de casos entre 1996 e 2002 ocorreu na macrorregião sul, seguida das macrorregiões nordeste e extremo oeste. CONCLUSÕES: Ainda é crescente o número de casos de hepatite B no Brasil e deve-se considerar que a subnotificação pode afetar os números apresentados. Em todo o Brasil, a vacinação deve ser estendida a adolescentes em regiões de prevalência moderada a alta.