Outbreak of influenza type A (H1N1) in Iporanga, São Paulo State, Brazil.

From June to July 1999 an outbreak of acute respiratory illness occurred in the town of Iporanga. Out of a total of 4,837 inhabitants, 324 cases were notified to the Regional Surveillance Service. Influenza virus was isolated from 57.1% of the collected samples and 100% seroconversion to influenza A (H1N1) was obtained in 20 paired sera tested. The isolates were related to the A/Bayern/07/95 strain (H1N1). The percentages of cases notified during the outbreak were 28.4%, 29.0%, 20.7%, 6.2% and 15.7% in the age groups of 0-4, 5-9, 10-14, 15-19 and older than 20 years, respectively. The highest proportion of positives was observed among children younger than 14 years and no cases were notified in people older than 65 years, none of whom had been recently vaccinated against influenza. These findings suggest a significant vaccine protection against A/Bayern/7/95, the H1 component included in the 1997-98 influenza vaccine for elderly people. This viral strain is antigenically and genetically related to A/Beijing/262/95, the H1 component of the 1999 vaccine. Vaccines containing A/Beijing/262/95 (H1N1) stimulated post-immunization hemagglutination inhibition antibodies equivalent in frequency and titre to both A/Beijing/262/95-like and A/Bayern/7/95-like viruses. Thus, this investigation demonstrates the effectiveness of vaccination against influenza virus in the elderly.

An outbreak of group C rotavirus gastroenteritis among adults living in Valentim Gentil, São Paulo State, Brazil.

An outbreak of gastroenteritis affecting adults and children occurred in the small city of Valentim Gentil, São Paulo, Brazil, in 1993. Nineteen faecal samples (from 10 cases and 9 contracts) were examined by direct electron microscopy (DEM), immune electron microscopy (IEM), polyacrylamide gel electrophoresis (PAGE), and enzyme-linked immunosorbent assay (ELISA) for group A and C rotaviruses. DEM detected rotavirus in 6 of the 10 cases and in none of the contacts. All of the samples were negative for group A rotavirus by ELISA. Analysis by PAGE showed an electrophoretic profile suggestive of group C rotavirus in two cases. Group C rotavirus was identified by IEM in 4 of the cases and in 1 of the contacts. All of the samples were submitted to ELISA for group C rotavirus. This resulted in a total of 10 positives-7 for diarrhoeal cases and 3 for contacts. This outbreak was strongly associated with group C rotavirus. The importance of combining different diagnostic methods is emphasised.

Enterovirus 71 infection and acute neurological disease among children in Brazil (1988-1990).

Surveillance for Enterovirus 71 (EV-71) infection in children up to 15 years of age was carried out in Brazil, from 1988 to 1990. Patients with acute neurological diseases (AND) such as flaccid paralysis, Bell's palsy, acute cerebellar ataxia and Guillain-Barré syndrome were included in the study. EV-71 infection was detected in 24 of 426 children (5.6%) with AND. EV-71 infection was confirmed only by virus isolation in 13 children, by virus isolation and seroconversion in 4, and by seroconversion alone in 7. EV-71 was also isolated from 15 of the 427 household contacts (3.5%) of 165 AND patients. There was some evidence of high infectivity of EV-71: household clusters were detected in the case of 7 of 24 children (29.1%) infected with EV-71 and manifesting AND; EV-71 was isolated from 11/40 household contacts (27.5%) of the infected patients but from only 4/387 household contacts (1.0%) of children in whom it was not possible to demonstrate EV-71 infection. Seven of the 24 children infected with EV-71 exhibited residual motor deficiency when examined 6 months after the disease onset. The relevance of these results for the Plan for Global Eradication of Wild Poliovirus is discussed, as well as the need to increase knowledge about the behaviour of this virus and its possible association with AND.

[Gastroenteritis and acute respiratory infections among children under 5 years old in an area of southeastern Brazil, 1986-1987. I--Acute respiratory infections]. / Gastroenterites e infecções respiratórias agudas em crianças menores de 5 anos em área da região sudeste do Brasil, 1986-1987. I--Infecções respiratórias agudas.

A probabilistic sample of children up to 5 years old was studied (n = 468). The epidemiological survey was carried out in five areas in the municipality of S. Paulo (Brazil), from March 1986 to May 1987. Data were obtained through household interviews once a month during one year. Some of the most relevant socioeconomic characteristics of the children's families are: low family income "per capita"; 29.3% of the parents were migrants with a mean period of residence in S. Paulo city of 18.6 years; 40% of the families had access exclusively to public or philanthropic health care services. Among the children included in the research, 87.3% were eutrophic, 94% were fully vaccinated, 90.6% had never been hospitalized as a consequence of acute respiratory infections (ARI). During the follow up of 1 year, 554 episodes of ARI with mean of 6.8 days of duration were identified. The incidence of ARI was 11.8 episodes per 100 children/month. The most vulnerable age group consisted of children up to one year of age. Thirty six percent of the ARI events were followed by at least one other case in the household. The index case in 53% of these cases were children up to 6 years old. Around 52.6% of the episodes did not require a medical assistance, 46.7% were assisted in ambulatory, 4 cases (0.7%) have had hospital treatment and only one died. The most frequent therapeutical conduct regarding children submitted to medical care assistance was the prescription of antibiotics and expectorants. Some factors related to social economic status and personal background such as living conditions and history of previous respiratory diseases were associated with higher incidence of ARI.

Human enterovirus infection in stray dogs. Some aspects of interest to public health.

To investigate the possible role of domestic animals as reservoirs of human enteroviruses, we studied 212 stray dogs captured in different areas of the municipality of São Paulo. The captured animals were divided into 19 groups of 10 to 20 dogs each; faeces of 126 of the 212 dogs were processed for enterovirus isolation. The following viruses were isolated from 12 dogs; poliovirus type 1 (2 dogs), poliovirus type 3 (1 dog), echovirus type 7 (8 dogs) and echovirus type 15 (1 dog). Of the 12 infected animals, four had specific homotypic neutralizing antibody titres > or = 16. All 212 animals were tested for the presence of neutralizing antibodies to human enteroviruses. The frequency of neutralizing antibodies present in titres of > or = 16 was 10.3%, 3.8% and 4.3% for vaccinal prototypes of polioviruses 1, 2 and 3 respectively; 1.9%, 1.4% and 1.5% for wild prototypes of the same viruses, 11.3% for echovirus 7, and 2.4% for echovirus 15. The proportion of dogs with neutralizing antibodies varied with the virus studied. Some indication of the susceptibility of dogs to infection with human enteroviruses was demonstrated, and the importance of this fact for the Plan for Global Eradication of the Wild Poliovirus is discussed.

An exanthematic disease epidemic associated with coxsackievirus B3 infection in a day care center.

An epidemic of exanthematic illness in a day care center is described. Ten children aged 7 to 13 months were affected by the illness. The exanthem was characterized by nonconfluent macular or maculopapular lesions that appeared on the face, body and limbs. Fifty percent of the infected children had fever of up to 39 degrees C at the beginning of the disease. Coxsackievirus B3 (CB3) was isolated from the stool of one ill child. Paired serum samples were obtained from eight ill children and six of them presented seroconversion to CB3. Antibodies to CB3 were detected at titers higher than 16 in a single serum sample collected from the other two patients. Neutralizing antibodies to CB3 were detected in 71.0% of the contact children.

Comparative study of adenoviruses with monoclonal antibodies.

The obtainment of monoclonal antibodies for adenovirus species 4(Ad4) is described. The specificities of selected monoclonal antibodies were determined by means of viral neutralization test in cell culture, immunofluorescence and Enzyme-Linked Immunosorbent Assay (ELISA), in the presence of the following species of human adenovirus: 1, 2, 5 (subgenus C), 4 (subgenus E), 7 and 16 (subgenus B) and 9 (subgenus D). Two monoclonal antibodies species specific to adenovirus 4 (1CIII and 3DIII) and one monoclonal antibody that cross reacted with adenovirus species 4 and 7 (2HIII) were obtained.

Comparison of enzyme-linked immunosorbent assay, indirect immunofluorescence assay, and virus isolation for detection of respiratory viruses in nasopharyngeal secretions.

Nasopharyngeal secretions obtained from 94 children with acute respiratory illness were examined for the presence of respiratory syncytial virus (RSV), adenovirus, and influenza virus type A by virus culturing (virus isolation technique [VIT]), immunofluorescence assay (IFA), and enzyme-linked immunosorbent assay (ELISA). Similar results were obtained in at least two tests for RSV, influenza virus type A, and adenovirus in 92 (97.9%), 88 (93.6%), and 88 (93.6%) cases, respectively. Both rapid virus detection methods showed good specificity for the diagnosis of these virus infections (greater than or equal to 90.7%) and were more sensitive than was VIT for RSV detection. In a more accurate statistical analysis, the indexes of agreement between VIT and ELISA were substantial for RSV (kappa = 0.69; zeta = 5.5; P less than 0.0001), influenza virus type A (kappa = 0.67; zeta = 5.3; P less than 0.0001), and adenovirus (kappa = 0.71; zeta = 6.0; P less than 0.0001), while it was almost perfect for RSV when ELISA was compared with IFA (kappa = 0.88; zeta = 5.7; P less than 0.0001). Although the observed agreement was good in the comparison of these two tests for these three viruses (89%0, the indexes of agreement were moderate in the comparison of IFA and VIT for RSV (K = 0.55; Z = 2.0; P < 0.05), influenza virus type A (K = 0.42; Z = 9.7; P < 0.0001), and adenovirus (K = 0.41; Z = 6.5; P < 0.0001) and of ELISA and IFA for influenza virus type A (K = 0.55; Z = 7.0; P < 0.0001) and adenovirus (K = 0.59; Z = 6.8; P < 0.0001). All of the statistical evaluations demonstrated better agreement between ELISA and VIT for influenza virus type A and adenovirus.

[Enterovirus 70 in the metropolitan region of São Paulo, Brazil, from 1984 to 1987: infection aspects in endemic and epidemic periods]. / Enterovírus-70 na região metropolitana de São Paulo, Brasil, de 1984 a 1987: aspectos da infecção em períodos epidêmico e endêmico.

Results of investigation about Enterovirus-70 (EV-70) as an etiologic agent of epidemic of acute haemorrhagic conjunctivitis (AHC) and neurological disease in the metropolitan area of São Paulo city are presented. During the first three months of 1984, in an epidemic period of AHC, 3 groups with a total of 291 persons were studied. The group A included 90 individuals affected by AHC; the 99 persons belonging to group B did not acquire the AHC but referred familiar contact with the ill individuals; the group C included 102 persons who denied the AHC or any contact with the illness. Neutralization test in BHK-21 cell culture was used for measurement of antibodies in sera. For the detection of the presence of IgM, indirect immunofluorescence assay was utilized. The presence of IgM antibodies was observed in 56.7%, 33.3% and 20.6% of persons belonging to groups A, B and C, respectively. The 10-29 age group was the most affected in the group A. From april 1984, after the end of epidemic period of AHC, until December 1987, three sporadic cases of AHC and 10 cases with acute neurological disease associated with recent infection by EV-70 were observed. Nine of 10 persons with acute neurological symptoms had paralysis of cranial nerves, all of them recovering without sequelae. The circulation of EV-70 in the population during the endemic period was maintained by either asymptomatic, sporadic cases of AHC or neurological diseases.

Preliminary characterization of a new virus isolated from the spinal fluid of patients with meningitis in São Paulo, Brazil.

A total of 138 patients with the age of 4 months to 57 years were attended in different hospitals of São Paulo State with aseptic meningitis. A probable new agent was isolated from the cerebrospinal fluid of 35 of 53 specimens examined. Replication of the agent with similar characteristics was detected by CPE produced in the MDCK cell line. Virus-like particles measuring about 40 nm in diameter were observed by negative staining electron microscopy. No hemagglutinating activity was detected at pH 7.2 by using either human, guinea pig, chicken and at pH ranged 6.0-7.2 with goose red blood cells. The agent was not pathogenic to newborn or adult mice. Virus infectivity as measured by CPE was sensitive to chloroform and not inhibited by BuDR, suggesting that agent is an enveloped virus with RNA genome.

Enzyme linked immunosorbent assay: determination of anti-adenovirus antibodies in an infant population.

In order to define an accurate assay for anti-adenovirus antibody detection, a recently developed ELISA was compared with IFA and CF. On 58 sera, the ELISA was more sensitive than both CF and IFA, which showed relative sensitivities of 63% and 94%, respectively. It was not possible to determine the exact specificity of the tests because of the lack of a gold standard. Furthermore, the ELISA was used to define the prevalence of adenovirus antibodies in 116 infants between 1 and 24 months old (mean 7.28). The data showed that maternal antibodies waned by the age of 5 to 6 months and that more than 80% of the children had been infected by adenoviruses by the age of 10 months.

Resumos de temas livres

Säo apresentados 7 pacientes com idade entre 6 meses e 10 anos que, sem antecedente prévio de conjuntivite, desenvolveram patologias neurológicas de forma aguda. 4 apresentaram paralisia facial periférica, 1, síndrome de Guillain-Barré, 1, síndrome poliomielítica e 1, encefalite. Estes pacientes foram submetidos à investigaçäo com o intuito de determinar a existência de desencadeante viral que constitiu em : isolamento de vírus nas fezes e no LCR (quando houvesse indicaçäo de punçäo liquórica); sorologia em duas amostras com intervalo de até 21 dias para enterovírus (poliovírus, Coxsackie A e B, ECHO, enterovírus 70 e 72), sarampo, rubéola, caxumba, Epstein-Barr, citomegalovírus, parainfluenza, influenza, adenovírus, vírus da coriomeningite linfocitária, varicela-zoster, herpes simplex e vírus sincicial respiratório. Näo foi isolado qualquer vírus no LCR de 3 pacientes em que foi feita punçäo e, o isolamento em fezes, foi igualmente negativo. A sorologica dos 7 pacientes mostrou evidências de infecçäo recente pelo enterovírus 70 (EV 70), caracterizada pela presença de anticorpos IgM pela técnica de (IMF) contra este vírus. Os dados do presente trabalho sugerem a existência de associaçäo entre infecçäo recente pelo EV 70 e afecçöes neurológicas agudas, especialmente de caráter paralítico.

Serologic studies on the behaviour of influenza virus type A in persons of greater Säo Paulo during 1976, 1978 and 1979

Foram estudados soros de pessoas de diferentes grupos etários coletados em 1976, 1978 e 1979 para verificar a presença de anticorpos inibidores da hemaglutinaçäo contra diversas estirpes de vírus da influenza A dos subtipos H3N2 e H1N1. A ocorrência da infecçäo pelo subtipo H3N2 foram detectados em 1976 e 1978 mas em 1979, a circulaçäo desse subtipo de vírus foi limitada. A prevalência de anticorpo contra A/Säo Paulo/1/78 (H1N1) foi significativamente maior do que para A/USSR/90/77 (H1N1) em 1978. No entanto em 1979, a estirpe predominante foi A/USSR/90/77 (H1N1). As pessoas com idade inferior a 20 anos foram as mais afetadas pelo subtipo H1N1, enquanto que indivíduos com mais de 20 anos já apresentavam anticorpos para esse subtipo em 1976, antes do resurgimento dessa estirpe. A infecçäo pelo vírus H3N2 em 1978 ocorreu em 65,4% de crianças do grupo etário de 0-4 anos; 47,0% de criancas do mesmo grupo tinham anticorpos para vírus H1N1 em 1979. Anticorpos para o vírus da influenza suina foram detectadas em 60% de pessoas com mais de 60 anos de idade

Influenza em Sao Paulo durante os anos 1976-1978. / Influenza in Sao Paulo during 1976-1978

A ocorrencia das infeccoes por virus da influenza A e B foi estudada na cidade de Sao Paulo, nos anos de 1976-78, atraves da tentativa de isolamento de virus e reacoes sorologicas. Nos tres anos consecutivos o virus da influenza do tipo A demonstrou variacao antigenica. Em 1976 foram detectadas infeccoes por virus antigenicamente relacionados ao A/Victoria/3/75 (H3N2), enquanto que em 1977, em sua maioria, os isolados demonstraram ser semelhantes ao A/Texas/1/77 (H3N2), mas a estirpe prevalente no ano anterior ainda continuou em circulacao. Em 1978 foi verificado o retorno do subtipo H1N1 que circulou nos anos 1947-1957. Esse virus demonstrou ligeira diferenca antigenica da estirpe A/USSR/90/77 (H1N1), prevalente naquela ocasiao em outros paises. Infeccoes por virus da influenza do tipo B foram detectadas em 1976 e 1977 mas nao foram verificadas em 1978

A prospective clinical study of the mononucleosis syndrome in a developing country.

A prospective aetiologic analysis made of 70 children and adults with the clinical and haematologic features of infectious mononucleosis (IM) in Sao Paulo, Brazil, revealed 65.7% due to EBV (31 heterophile antibody positive (HA+), 15 HA negative (HA-) cases), 8.6% due to T. gondii and 4.3% due to CMV. One case was related to viral hepatitis and one to drug hypersensitivity. The other 18.6% were of unknown cause. In the 46 IM cases positive tests were found for EBV/IgM in 93.5%, for heterophile by the absorbed horse Rbc test in 64.2% and by sheep Rbc in 37%. The immune-adherence haemagglutination test was slightly more sensitive than the horse Rbc test in 39 IM sera tested. In 41 EBV/IgM positive sera, EBV/IgA was present in 17/25 containing heterophile antibody and in 2/16 lacking heterophile antibody; anti-EA was present in 85%. The average age of HA+ IM cases was 13.2 years and of HA- cases 4.7 years. Three HA+ and 5 HA- IM cases occurred in the 0-2 year old age group. Few clinical features differentiated between aetiological agents. Exudative tonsillitis was the most helpful one and occurred in 67.7% of HA+ IM cases, 26.7% of HA- cases, in 1 of 3 CMV cases, and not at all in 6 T. gondii infections.