ABSTRACT
The capybara (Hydrochoerus hydrochaeris) is the largest rodent in the world. In the state of Acre, Brazil, populations of capybaras have been increasing significantly. The role of capybaras in the transmission of certain bacterial zoonotic infections is not well understood, including bacteria of the genus Salmonella. Salmonella spp. generally cause enteritis or septicemia in mammals, however many mammalian species can carry the bacteria asymptomatically and shed it in their feces. To better understand the possible role of capybaras as reservoirs of Salmonella spp., we conducted a study of Salmonella within fecal samples from capybara in Acre. In a convenience sample, 54 capybaras from two urban and two rural areas of Acre were captured and kept for three to four days for sampling. None of the animals were symptomatic of any intestinal illness. Three separate fecal samples were collected from each animal, during their stays in captivity. Each sample was cultured for the presence of Salmonella spp. at the bacteriology laboratory of the Veterinary College of the Federal University of Acre. Samples were seeded in tetrationate pre-enrichment broth and in pre-enrichment broth peptone. After a 24 hour of incubation all samples were streaked on MacConkey Agar (MC) and Salmonella-Shigella Agar (SS). Suggestive colonies were submitted to biochemical analysis. Salmonella compatible colonies according to biochemical profile were submitted to serotyping (Sorokit for Salmonella - Probac do Brasil). In addition, the first sample from each of the 54 capybara was tested for Salmonella spp. using PCR targeting gene hilA. Eight (5%) of the 162 samples examined by bacterial culture were positive for Salmonella spp., while four (7%) of the 54 examined by PCR were positive. From the eight positive animals on culture, five were from urban area and three from rural area. On PCR, only one positive animal was from urban area and four were from rural area. Overall, by either test, one of the 54 animals was positive. All samples were collected in free - living animals with no apparent clinical signs of salmonellosis, indicating the potential of capybara as reservoir on this ecosystem.(AU)
A capivara (Hydrochoerus hydrochaeris) é o maior roedor do mundo. No estado do Acre, Brasil, as populações de capivaras têm aumentado significativamente. O papel das capivaras na transmissão de certas infecções zoonóticas bacterianas não é bem compreendido, incluindo as bactérias do gênero Salmonella. Salmonella spp. geralmente causam enterite ou septicemia em mamíferos, porém muitas espécies de mamíferos podem carregar a bactéria de forma assintomática e eliminá-la em suas fezes. Para entender melhor o possível papel das capivaras como reservatórios de Salmonellaspp., realizamos um estudo para identificação de Salmonella spp. em amostras fecais de capivaras no Acre. Em uma amostra de conveniência, 54 capivaras de duas áreas urbanas e duas áreas rurais do Acre foram capturadas e mantidas por três a quatro dias para amostragem. Nenhum dos animais era sintomático de qualquer doença intestinal. Três amostras fecais foram coletadas de cada animal, durante sua permanência em cativeiro. Cada amostra foi cultivada para a presença de Salmonella spp. no Laboratório de Bacteriologia Veterinária da Universidade Federal do Acre. As amostras foram semeadas em caldo de pré-enriquecimento tetrationato e em peptona de caldo de pré-enriquecimento. Após 24 horas de incubação, todas as amostras foram semeadas em ágar MacConkey (MC) e ágar Salmonella-Shigella (SS). Colônias sugestivas foram submetidas a análises bioquímicas. Colônias compatíveis com Salmonella de acordo com o perfil bioquímico foram submetidas à sorotipagem (Sorokit para Salmonella - Probac do Brasil). Além disso, a primeira amostra de cada uma das 54 capivaras foi testada para Salmonella spp. usando PCR, visando gene hilA. Oito (5%) das 162 amostras examinadas por cultura bacteriana foram positivas para Salmonella spp. Enquanto quatro (7%) das 54 examinadas pela PCR foram positivas. Dos oito animais positivos em cultura, cinco eram de área urbana e três de área rural. Na PCR, apenas um animal positivo era de área urbana e quatro de área rural. Considerando o diagnóstico conjunto por ambos os testes, PCR e cultura, um animal foi considerado positivo. Todas as amostras foram coletadas em animais livres, sem sinais clínicos aparentes de salmonelose, indicando o potencial da capivara como reservatório nesse ecossistema.(AU)
Subject(s)
Animals , Rodentia/microbiology , Salmonella , Salmonella Infections/diagnosis , Feces/microbiologyABSTRACT
The reported incidence of leptospirosis increased 30-fold in Thailand between 1995 and 2000. Despite many hypotheses to explain the increase, the true etiology remains unknown. We conducted a review of the national surveillance system for leptospirosis, examining the reporting practices, system attributes, and utilization of laboratory confirmation in two northeastern provinces. Using standard guidelines for evaluation of public health surveillance systems, we assessed the timeliness, completeness, and accuracy of data; the sensitivity and specificity of case ascertainment; and the overall usefulness of the Thai leptospirosis surveillance system. Physicians were interviewed to assess compliance and understanding of the case definition. Capacity for confirmation of leptospirosis by a Thai latex agglutination test was assessed. Completeness for variables critical for linking epidemiologic and laboratory data for leptospirosis was 69%. Twenty-eight percent of 208 provincial surveillance reports were considered timely. Interviewed physicians indicated that the national case definition was difficult to understand and apply, and that laboratory confirmation was infrequently used. Compared to a standardized microscopic agglutination test (MAT) panel, the Thai test was specific, but relatively insensitive. We found that a lack of a standardized case definition for leptospirosis, the infrequent use of confirmatory laboratory testing, and the inability to link clinical, epidemiologic, and laboratory data hindered system utility. This surveillance system for leptospirosis highlights difficulties with surveillance of febrile illnesses in general, and the importance of laboratory confirmation for infections that are difficult to diagnose clinically.
Subject(s)
Centers for Disease Control and Prevention, U.S. , Disease Outbreaks , Humans , Incidence , Interviews as Topic , Clinical Laboratory Techniques/standards , Latex Fixation Tests , Leptospirosis/diagnosis , Sentinel Surveillance , Thailand/epidemiology , United States , World Health OrganizationABSTRACT
Entre junho e setembro de 2000, 9 pessoas de uma área pobre da zona norte do Rio de Janeiro, Brasil, desenvolveram uma doença febril hemorrágica e morreram. Foi conduzida uma busca ativa para determinar a extensão do surto e um estudo de caso-controle para identificar a etiologia e os fatores de risco para aquisição da doença. Um paciente-caso foi definido como residente da área afetada apresentando febre, cefaléia e um ou mais dos seguintes sintomas - mialgia, artralgia, diarréia, manifestações hemorrágicas ou icterícia - durante o período de junho a setembro de 2000, tendo procurado serviço médico. Quarenta e três pessoas enquadraram-se na definição de caso e foram comparados com 86 controles, pareados por área de residência e faixa etária. Vinte e três (53,3%) eram do sexo masculino e a idade mediana foi de 19 anos. Na análise univariada, contato com esgoto (mOR=2,5; p=0,02); contato com ratos (mOR=3,0; p=0,006), contato com rio (mOR=3,3; p=.009), e mortandade de animais no peridomicílio (mOR=2,7; p=0,04), foram significantemente associados ao desenvolvimento de doença. Na análise multivariada, contato com ratos (OR=5,1; p=0,03) e contato com rio (OR=4,9; 95%; p=0,04) permaneceram como fatores de risco independentemente associados ao desenvolvimento de doença. A imunohistoquímica de uma amostra de tecido de um caso fatal foi positiva para leptospirose. Exames adicionais para outros potenciais agentes estão pendentes. Com base nas evidências epidemiológicas fornecidas pela investigação, recomendamos a implementação de desratização na área afetada e educação em saúde aos residentes, para que evitassem contato com o rio local. Após a implementação das medidas de controle nenhum caso novo foi notificado. Esta investigação ressalta a importância de se instituir recomendações de saúde pública com base em resultados de investigações epidemiológicas quando exames laboratoriais não estão prontamente disponíveis.
In June-September 2000, nine persons from a poor area north of Rio de Janeiro, Brazil, developed a febrile hemorrhagic illness and died. We conducted case finding to determine the outbreak size, and a case-control study to identify disease etiology and risk factors. A case-patient was defined as a resident of the affected area who sought medical care during June-September 6, 2000, presenting with fever, headache, and one or more of the following symptoms: myalgia, arthralgia, diarrhea, hemorrhagic manifestations, or jaundice. Forty-three persons met the case definition and were compared with eighty-six controls matched by area of residence and age group. Twenty-three (53.3%) were males with a median age of 19 years. In univariate analysis, contact with sewage (matched Odds Ratio [mOR]=2.5; p=0.02), contact with rats (mOR=3.0; p=0.006), contact with local creek (mOR=3.3; p=0.009), and mortality of household animals (mOR=2.7; p=0.04), were associated with development of the disease. In multivariate analysis, contact with rats (mOR=4.7; p= 0.03), and contact with local creek (mOR=4.8; 95%; p= 0.04) remained as independent risk factors. Immunohistochemical evaluation of tissue samples from one fatal case was positive for leptospirosis. Further laboratory testing for potential etiologies is pending. Based on the epidemiologic evidence provided by our investigation we recommended implementation of rodent extermination in the affected area, and education of residents to avoid contact with the local creek. Following implementation of these control measures, further cases were not reported. This investigation highlights the value of implementing public health recommendations based on results from epidemiologic investigations when laboratory testing is not immediately available.