ABSTRACT
Leptospirosis is among the most important zoonotic diseases in (sub-)tropical countries. The research objective was to evaluate the accuracy of the Serion IgM ELISA EST125M against the Microscopic Agglutination Test (MAT = imperfect reference test); to assess its ability to diagnose acute leptospirosis infections and to detect previous exposure to leptospires in an endemic setting. In addition, to estimate the overall Leptospira spp. seroprevalence in the Wiwa indigenous population in North-East Colombia. We analysed serum samples from confirmed leptospirosis patients from the Netherlands (N = 14), blood donor sera from Switzerland (N = 20), and sera from a cross-sectional study in Colombia (N = 321). All leptospirosis ELISA-positive, and a random of negative samples from Colombia were tested by the MAT for confirmation. The ELISA performed with a sensitivity of 100% (95% CI 77% - 100%) and a specificity of 100% (95% CI 83% - 100%) based on MAT confirmed Leptospira spp. positive and negative samples. In the cross-sectional study in Colombia, the ELISA performed with a sensitivity of 100% (95% CI 2-100%) and a specificity of 21% (95% CI 15-28%). Assuming a 5% Leptospira spp. seroprevalence in this population, the positive predictive value was 6% and the negative predictive value 100%. The Leptospira spp. seroprevalence in the Wiwas tested by the ELISA was 39%; however, by MAT only 0.3%. The ELISA is suitable to diagnose leptospirosis in acutely ill patients in Europe several days after onset of disease. For cross-sectional studies it is not recommended due to its low specificity. Despite the evidence of a high leptospirosis prevalence in other study areas and populations in Colombia, the Wiwa do not seem to be highly exposed to Leptospira spp.. Nevertheless, leptospirosis should be considered and tested in patients presenting with febrile illness.
Subject(s)
Leptospira , Leptospirosis , Agglutination Tests , Antibodies, Bacterial , Colombia/epidemiology , Cross-Sectional Studies , Enzyme-Linked Immunosorbent Assay , Humans , Immunoglobulin M , Indigenous Peoples , Leptospirosis/diagnosis , Leptospirosis/epidemiology , Sensitivity and Specificity , Seroepidemiologic StudiesABSTRACT
OBJETIVO: Calcular los índices infestación por triatominos en comunidades indígenas en Colombia. MÉTODOS: Se realizó estudio descriptivo en 19 comunidades indígenas del municipio de Valledupar Departamento de Cesar, Colombia. Durante junio a diciembre de 2007 se recolectaron triatominos por búsqueda activa en las viviendas de los indígenas. Los insectos luego fueron identificados por las claves de Lent & Wygodzinsky. Se desarrolló estudio del proceso infectivo en modelo animal y análisis enzimático de cepas de Trypanosoma cruzi, detectadas en heces de triatominos. RESULTADOS: Rhodnius prolixus presentó índice de densidad en las viviendas de 154,7 por ciento, Triatoma dimidiata de 102,45 por ciento, Triatoma maculata de 109,25 por ciento y Panstrogylus geniculatus de 0,3 por ciento. El índice promedio de infestación de las cuatro especies fue de 40,54 por ciento y, el de infección con T. cruzi de 9,4 por ciento. De cinco hemocultivos positivos para T. cruzi, tres se caracterizaron por isoenzimas, clasificándose en T. cruzi grupo I. El estudio de las biopsias reveló pocas características patológicas durante el proceso de infección con las cepas de T. cruzi aisladas de triatominos domiciliados. CONCLUSIÓN: Los altos índices de infestación por triatominos en las viviendas y el índice de infección por T. cruzi, evidencian la transmisión activa de la enfermedad de Chagas, situación que amerita la aplicación de medidas de control vectorial y el estudio seroepidemilógico de la población en riesgo. La identificación de las cepas de T. cruzi como grupo I concuerda con otros estudios realizados en esta región colombiana.
OBJECTIVE: To calculate triatomine infestation indices in indigenous communities in Colombia. METHODS: A descriptive study was carried out in 19 communities in Valledupar Municipality, Cesar Department, Colombia. During June to December, 2007, triatromine bugs were collected from their resting places in households. Taxonomic identification was made according to the keys by Lent & Wygodzinsky. An infection process in animal model and isozyme analysis of triatomine feces were performed. RESULTS: Rhodnius prolixus showed a density index of 154.7 percent, for Triatoma dimidiata was 102.45 percent, T. maculata 109.25 percent and Panstrogylus geniculatus 0.3 percent. The mean infestation index was 40.54 percent, and mean Trypanosoma infection index was 9.4 percent. Of five hemocultures positive for T. cruzi, three were enzimatically identified as T. cruzi group I. Biopsies revealed few pathologic characteristics of infective process with these strains isolated from domiciliary triatomine bugs. CONCLUSIONS: The high triatomine infestation indices in households and the T. cruzi infection index are evidence of active transmission of Chagas disease. The situation merits a vector control program and serological survey of the population at risk. The genetic characterization of T. cruzi strains as group I agrees with other findings on strains in this region of Colombia.
OBJETIVO: Calcular índices de infestação por barbeiros em comunidades indígenas da Colômbia. MÉTODOS: Estudo descritivo em 19 comunidades do município de Valledupar, departamento de Cesar, Colômbia. A coleta de barbeiros foi realizada por busca ativa nas casas dos indígenas de junho e dezembro de 2007. A identificação taxonômica foi feita conforme Lent & Wygodzinsky. A determinação da infecção foi realizada por processo de infecção em modelo animal e análise enzimática em fezes de barbeiros. RESULTADOS: Rhodnius prolixus apresentou nas casas das comunidades um índice de densidade 154,7 por cento, Triatoma dimidiata de 102,45 por cento e T. maculata de 109,25 por cento e Panstrogylus geniculatus de 0,3 por cento, cujo índice de infestação foi de 40,54 por cento, e índice de infecção com T. cruzi de 9,4 por cento. De cinco hemocultivos positivos para T. cruzi, três caracterizam-se como T. cruzi grupo I. O estudo das biópsias revelou poucas características patológicas da identificação do processo de infecção das cepas isoladas a partir de barbeiros domiciliados. CONCLUSÕES: os altos índices de infestação por barbeiros nas casas e o índice de infecção por T. cruzi evidenciam a transmissão ativa da doença de Chagas, situação que merece a aplicação de medidas de controle vetorial e um estudo seroepidemiológico da população sob risco. A caracterização genética das cepas de T. cruzi como grupo I concorda com outros achados para cepas dessa região da Colômbia.
Subject(s)
Animals , Humans , Mice , Chagas Disease , Insect Vectors , Triatominae , Trypanosoma cruzi , Biopsy , Chagas Disease , Colombia , Housing , Indians, South American , Insect Vectors , Mice, Inbred ICR , Residence Characteristics , Risk Assessment , Risk Factors , TriatominaeABSTRACT
OBJECTIVE: To calculate triatomine infestation indices in indigenous communities in Colombia. METHODS: A descriptive study was carried out in 19 communities in Valledupar Municipality, Cesar Department, Colombia. During June to December, 2007, triatromine bugs were collected from their resting places in households. Taxonomic identification was made according to the keys by Lent & Wygodzinsky. An infection process in animal model and isozyme analysis of triatomine feces were performed. RESULTS: Rhodnius prolixus showed a density index of 154.7%, for Triatoma dimidiata was 102.45%, T. maculata 109.25% and Panstrogylus geniculatus 0.3%. The mean infestation index was 40.54%, and mean Trypanosoma infection index was 9.4%. Of five hemocultures positive for T. cruzi, three were enzimatically identified as T. cruzi group I. Biopsies revealed few pathologic characteristics of infective process with these strains isolated from domiciliary triatomine bugs. CONCLUSIONS: The high triatomine infestation indices in households and the T. cruzi infection index are evidence of active transmission of Chagas disease. The situation merits a vector control program and serological survey of the population at risk. The genetic characterization of T. cruzi strains as group I agrees with other findings on strains in this region of Colombia.
