[Serological survey on arbovirus infection in residents of an ecological reserve]. / Inquérito soroepidemiológico para pesquisa de infecções por arbovírus em moradores de reserva ecológica.

OBJECTIVE: Serological inquires conducted in the Ribeira Valley, S. Paulo State, Brazil, showed an intense circulation of pathogenic arboviruses in the region. The goal was to verify the prevalence of arboviral infections in people living at the local ecological, and its potential association with these population' individual and familiar characteristics. METHODS: The study was carried out among 182 persons of 58 families to identify the presence of antibodies to the following viruses: Rocio (ROC), Ilheus (ILH), Eastern equine encephalitis virus (EEE), Western equine encephalitis virus (WEE), Venezuelan equine encephalitis virus (VEE) and St. Louis encephalitis virus (SLE). Inhibition hemagglutination test and plaque reduction neutralization test were the laboratory assays of choice. MAC-ELISA was used to identify IgM antibodies to ROC, ILH and EEE viruses. RESULTS: The prevalence of antibodies was 26.9% (21. 4% to alphavirus and 12.6% to flavivirus). There were no antibodies to WEE virus. IgM antibodies were not observed suggesting no recent infection in study population. Among the characteristics investigated, age, occupation, place of birth and the habit of going into the forest were shown to be statistically associated with arboviral infection (p<0.05). CONCLUSIONS: It was observed an intense circulation of pathogenic arboviruses, especially VEE. It seems the habit of going into the forest is the most important factor to this population exposure to the mosquito vectors of arboviruses. The results suggest the need of further investigation to clarify the role of birds as arbovirus infection amplificators indoors.

[Epidemiology of accidents due to bites of poisonous snakes: a study of cases attended in 1988]. / Epidemiologia do acidente por serpentes peçonhentas: estudo de casos atendidos em 1988.

The attendance given to patients by ta specialized Hospital, in S. Paulo, Brazil, during 1988 is studied. The study is based on the medical records of 322 patients and on questionnaires filled out by author during interviews with 209 patients or their companions. The 322 snake-bites occurred mainly between October and April, in the diurnal period, mainly in the afternoon. Most of patients were adult males, mainly between 10 and 20 years of age. The parts of the body most frequently affected were the feet, hands and legs. The snakes of the genera Bothrops, Crotalus and Micrurus were responsible, respectively, for 306 (95.0%) 14 (4.4%) and 2 (0.6%) of the accidents under study. Among the 160 snakes that were classified at the Herpetological Section of the IB, 152 were Bothrops; 142 B. Jararaca, mostly young reptiles, and 8 were of the genus Crotalus. Of the patients, 90.4% recovered completely, 2.2% presented sequelae, 7.5% were transferred and thus it was impossible to follow them up. Of the 209 persons interviewed, the occupational group most prone to snake bites was agricultural workers, followed by studentes; nearly 60% of the accidents ocurred during work; most of the patients had their inferior extremities unprotected at the moment of the bite. On hundred and sixty patients (76.6%) submitted to some from of treatment before coming to the HVB-IB, the more common being the use of a tourniquet (50.2%), local squeezing in an attempt to remove part of the venom (33.5), application of substances on the site of the snake bite (36.8%) and the ingestion of others (12.9%). Slightly over a quarter of the patients underwent some kind of medical treatment before coming to the HVB-IB, the most common being antissepsis (8.2%), administration of antivenom (6.2%), antihistamines (5.7%) and analgesics (5.3%). The snake was seen before it struch by 187 (89.5%) of the 209 persons interviewed and in most cases it adopted the strike posture just before the first bite.

[Current status of the eco-epidemiological knowledge on arboviruses pathogenic to humans in the Atlantic Forest region of the State of São Paulo]. / Situação atual do conhecimento eco-epidemiológico sobre arbovírus patogênicos para o homem na região da Mata Atlântica do Estado de São Paulo.

The available eco-epidemiologic information on pathogenic arbovirus to humans in the Atlantic Forest region of the State of São Paulo were analysed. According to this information arbovirus transmission cycles are proposed.

Infecçäo humana por Hantavirus no sul e sudeste do Brasil / Human infection by Hantavirus in southern and southeastern Brazil

Descrevem-se os resultados de inquérito sorológico para pesquisa de anticorpos de Hantavírus conduzido de fevereiro de 1986 a agosto de 1990, em grupos populacionais humanos dos Estados de Säo Paulo e Paraná, que apresentavam estreito contato com ratos urbanos ou com roedores e outros pequenos mamíferos silvestres. OBJETIVO. Identificar infecçäo humana causada por Hantavírus, agentes etiológicos da febre hemorrágica com síndrome renal. MÉTODOS. Os soros de 1.063 pessoas foram examinados com técnica imunoenzimática para detecçäo de anticorpos IgG e IgM utilizando-se antígenos dos vírus Hantaan, Seoul e Puumala. Nos soros positivos realizou-se teste de neutralizaçäo com reduçäo em placa para os mesmos antígenos e imunofluorescência indireta para o antígeno do vírus Hantaan. RESULTADOS. Observou-se presença de anticorpos anti-Hantavirus em 32 pessoas, evidenciados por testes imunoenzimáticos e de imunofluorescência. Em cinco delas foram positivos os testes de neutralizaçäo com reduçäo em placa (três para o vírus Scoul e dois para o vírus Pumala). Uma dessas pessoas apresentou alto título em todos os testes para o vírus Seoul. Trata-se de um morador da zona rural da regiäo do vale do Ribeira, que nasceu, sempre viveu no local e nunca viajou para fora do Estado de Säo Paulo. CONCLUSOES. Há evidências sorológicas de infecçäo causada por Hantavírus em moradores de área rural da Ilha do Amparo, Baia de Paranaguá, e da regiäo do Vale do Ribeira, Estado de Säo Paulo, em portuários de Paranaguá, Estado do Paraná, e em doentes internados com suspeita de leptospirose no Hospital Emílio Ribas, Säo Paulo

Surveillance of arbovirus infections in the Atlantic Forest Region, State of São Paulo, Brazil. I. Detection of hemagglutination-inhibiting antibodies in wild birds between 1978 and 1990.

We report data related to arbovirus antibodies detected in wild birds periodically captured from January 1978 to December 1990 in the counties of Salesópolis (Casa Grande Station), Itapetininga and Ribeira Valley, considering the different capture environments. Plasmas were examined using hemagglutination-inhibition (HI) tests. Only monotypic reactions were considered, except for two heterotypic reactions in which a significant difference in titer was observed for a determined virus of the same antigenic group. Among a total of 39,911 birds, 269 birds (0.7%) belonging to 66 species and 22 families were found to have a monotypic reaction for Eastern equine encephalitis (EEE), Venezuelan equine encephalitis (VEE), Western equine encephalitis (WEE), Ilheus (ILH), Rocio (ROC), St. Louis encephalitis (SLE), SP An 71686, or Caraparu (CAR) viruses. Analysis of the data provided information of epidemiologic interest with respect to these agents. Birds with positive serology were distributed among different habitats, with a predominance of unforested habitats. The greatest diversity of positive reactions was observed among species which concentrate in culture fields.

[Human infection by Hantavirus in southern and southeastern Brazil]. / Infecção humana por Hantavírus no Sul e Sudeste do Brasil.

The results of serological investigation on Hantavírus antibodies carried out between February 1986 and August 1990 in human populations of the States of São Paulo and Paraná, Brazil, which had close contact with urban rats or wild rodents and others small mammals are described. OBJECTIVE--To identify the human infection caused by Hantavíruses, which are the etiological agents of Hemorrhagic fever with renal syndrome. METHODS--Sera from 1063 persons were tested by enzyme immunoassay (ELISA) to Hantaan, Seoul and Puumala antigens. Plaque reduction neutralization test to the same antigens and indirect immunofluorescent test to Hantaan antigen were performed in the positive sera. RESULTS--Antibodies to Hantaan, Seoul or Puumala viruses were detected in 32 persons by enzyme immunoassay (ELISA) and immunofluorescent test. Plaque reduction neutralization test performed in these 32 sera were positive in 5 (3 for Puumala and 2 for Seoul viruses). One serum reacted with high titer to Seoul virus in all tests. It was from a male resident in the rural area of Ribeira Valley, State of São Paulo, where he was born and has always lived. He had only travelled inside the State of São Paulo. CONCLUSION--There are serological evidences of Hantavírus infections in residents of the rural areas of the Amparo Island, Paranaguá Bay, State of Paraná and the Ribeira Valley, State of São Paulo; in employees of the port of Paranaguá, State of Paraná and in patients of the Emílio Ribas Hospital, São Paulo, State of São Paulo, who had a presumptive diagnosis of leptospirosis.

Circulation of eastern equine encephalitis, western equine encephalitis, Ilhéus, Maguari and Tacaiuma viruses in equines of the Brazilian Pantanal, South America.

Neutralizing antibodies to EEE (6.7%), WEE (1.2%), ILH (26.6%), MAG (28.2%) and TCM (15.7%) viruses were found in sera of 432 equines of the Brazilian Pantanal, area where undiagnosed horse deaths are frequently observed. A 4-fold rise in CF titer to EEE virus was detected in acute and convalescent sera of an encephalitis horse sacrificed in 1992. Antibodies to EEE, ILH, MAG and TCM viruses were detected in horses less than 2 years old indicating recent circulation of these viruses in the Pantanal. The evidence of recent equine encephalitis associated with rising CF titer to EEE warrants a more intensive study with attempts to isolate virus from horses with clinical manifestations of encephalitis.

Relationship between the prevalence of antibodies to hepatitis B core antigen and arbovirus in fishermen from the Ribeira Valley, Brazil.

Sera from 299 fishermen 16 to 80 years old, residents in Cananeia and Iguape counties, southern cost of São Paulo State, Brazil, were studied in order to identify a possible association between the prevalence of specific antibodies to the hepatitis B virus (HBV) and exposure to haematophagus mosquitoes evaluated by the prevalence of arbovirus antibodies. This professional group presented the highest prevalence of arbovirus antibodies (54.1%) in past investigations carried out in this heavily forested region. Detection of antibody to hepatitis B core antigen (anti-HBc) in the sera was done by enzyme immunoassay (Roche). Prevalence of anti-HBc antibodies in this group was 31.4% (94/299) which is very high compared with 7.2% to 15.0% for different groups of healthy adults in State of São Paulo. No significant difference is observed between the prevalences of HBV antibodies in Iguape and Cananeia. Prevalence of anti-HBc and anti-arbovirus antibodies increases with age. There is a concordance in the distribution according to age groups of the frequency of anti-HBc and anti-arbovirus positive sera. Ag HBs was detected in 4% of the studied sera. These results support the hypothesis that the transmission of the hepatitis B virus and the arboviruses may be due to the same factor, one of the possibilities would be by anthropophilic mosquitoes.

Relationship between the prevalence of antibodies to arbovirus and hepatitis B virus in the Vale do Ribeira region, Brazil.

280 students, between 6 and 14 years old, residents in the Iguape county, southern coast of the State of São Paulo, were studied in order to identify the existence of a possible association between the prevalence of specific antibodies to the hepatitis B virus and the exposure to haematophagous mosquitoes, evaluated indirectly through the prevalence of antibodies to 17 arboviruses isolated in Brazil. The children were from 4 areas with different topographical characteristics: 89 of the children were from the urban zone of the town of Iguape, 89 were from the peri-urban zone, 30 were from the rural area with extensive banana plantations, and 72 were from the jungle zone. Previous studies had shown significantly higher prevalence of antibodies to different arboviruses in the cultivated zone and the jungle zone, when compared to the urban and peri-urban zones of Iguape. The detection of antibodies to the HBV surface antigen (HBs Ag) was done through the radioimmunoassay (Ausab, Abbott Laboratory). The cases considered positive were confirmed through the presence of anti-core HBV antibodies (anti-HBc-EIA Roche). A significantly higher prevalence of anti-HBV antibodies was observed in children from the jungle zone (26/72 = 36.1%) when compared to those from the urban zone (5/89 = 5.6%), peri-urban (6/89 = 6.7%) or from the cultivated zone (0/30 = 0%). The result suggest the existence of a common factor in the dissemination of the arboviruses and the hepatitis B virus, supporting the hypothesis that mosquitoes may play an important role in the HBV transmission in tropical forested region.

[Recent occurrence of human infection by Rocio arbovirus in the Valley of Ribeira region]. / Ocorrência recente de infecção humana por arbovírus Rocio na região do Vale do Ribeira.

The presence of IgM antibodies to Rocio in sera of two children from rural area of Ribeira Valley, Brazil, was detected by MAC-ELISA. This new arbovirus of the Flaviviridae family was responsible for an extensive encephalitis epidemic that occurred in the region in 1975-1977. Since 1980 no human disease caused by this virus has been diagnosed. An improvement on surveillance of Rocio infections and on the researches for virus identification in suspected vectors and reservoirs is necessary.