Microscopical and serological diagnosis of wuchereria bancrofti

Venous blood from 292 patients attending a Filaria Clinic in Georgetown, Guyana, was assayed by ELISA for IgG and IgM antibodies and by Indirect Haemagglutination Antibody Assay (IHA) against filaria parasites. They were also assayed by microscopic methods before and after concentration procedures for microfilaraemia. Of the 41 blood samples microscopically positive for Wuchereria bancrofti microfilfariae, 87.8 percent (ELISA IgG), 65.9 percent (ELISA IgM) and 73.2 percent (IHA) occurred in samples with subdiagnostic serological threshold titres of<1:32 (IgG and IgM) and <1:128(IHA). But indicators of value based on the standards of the presence of chronic and acute symptoms, the IgG and IgM diagnostic data gave 79.9 percent sensitivity, 96.4 percent specificity, 97.1 percent positive predictable value and 44.3 percent negative predictive value. A membrane filtration system (92.7 percent) was slightly better than a centrifugation technique (90.2 percent), but more efficient than a thick smear preparation (75.6 percent) for the detection of microfilariae. The filtration system was vastly supeior for yields of microfilariae. However, the Knott's concentration (sedimentation) was the most economical in terms of technical time and materials. Most microscopically confirmed filaria cases were in the 20 - 29-year age group (25 percent), followed by the broad 30--69-year age groups (10-12 percent). Males were significantly more commonly affected by the ratio 24.2:6.0. It is recommended that skills and materials for concentration of microfilariae from peripheral blood be maintained in all Caribbean countries. In known filaria endemic countries, it is recommended that the serological tool be used as an aid in diagnosis for patients with acute and chronic symptoms. (AU)

Microscopical and serological diagnosis of wuchereria bancrofti

Venous blood from 292 patients attending a Filaria Clinic in Georgetown, Guyana, was assayed by ELISA for IgG and IgM antibodies and by Indirect Haemagglutination Antibody Assay (IHA) against filaria parasites. They were also assayed by microscopic methods before and after concentration procedures for microfilaraemia. Of the 41 blood samples microscopically positive for Wuchereria bancrofti microfilfariae, 87.8//(ELISA IgG), 65.9//(ELISA IgM) and 73.2//(IHA) occurred in samples with subdiagnostic serological threshold titres of<1:32 (IgG and IgM) and <1:128(IHA). But indicators of value based on the standards of the presence of chronic and acute symptoms, the IgG and IgM diagnostic data gave 79.9//sensitivity, 96.4//specificity, 97.1//positive predictable value and 44.3//negative predictive value. A membrane filtration system (92.7//) was slightly better than a centrifugation technique (90.2//), but more efficient than a thick smear preparation (75.6//) for the detection of microfilariae. The filtration system was vastly superior for yields of microfilariae. However, the Knott's concentration (sedimentation) was the most economical in terms of technical time and materials. Most microscopically confirmed filaria cases were in the 20 - 29-year age group (25//), followed by the broad 30--69-year age groups (10-12//). Males were significantly more commonly affected by the ratio 24.2:6.0. It is recommended that skills and materials for concentration of microfilariae from peripheral blood be maintained in all Caribbean countries. In known filaria endemic countries, it is recommended that the serological tool be used as an aid in diagnosis for patients with acute and chronic symptoms

A comparative study of available diagnostic tools for lymphatic filariasis - abstract

Venous blood from 300 patients attending a filaria clinic in Georgetown, Guyana, was taken and assayed by ELISA for IgG and IgM antibodies against filaria parasites, and by microscopic methods before and after concentration procedures for microfilaraemia. Negative serum titres (<1:32) of IgG and IgM coincided with 90 per cent and 65 per cent, respectively, of positive microscopy. A membrane filtration system (95 per cent) was slightly better than a centrifugation (92.5 per cent) technique, but significantly more efficient than a thick smear preparation (75 per cent) for the detection of microfilaraemia. The filtration system was vastly superior for yields of microfilaria. However, the Knott's concentration (sedimentation) was the most economical in terms of technician time and materials. Most microscopically confirmed filaria cases were in the 20 - 29 year-age group (25 per cent), followed by the broad 30 - 69 year-age group (10 - 12 per cent). Males were more commonly affected by the ratio of 2.6 : 1. Symptoms included swollen limbs, tenderness, fever, swollen glands, headache and joint pains but 17 (42.5 per cent) patients were asymptomatic (AU)

Prevalencia de Wuchereria Bancrofti en Georgetown, Guyana / Prevalence of Wuchereria Bancrofti in Georgetown, Guyana

Para calcular la prevalencia de microfilariasis Wuchereria bamcrofti en Georgetown, Guyana, se realizó una encuesta en una muestra aleatoria de la población. Se examinaron frostis de sangre extraída durante la noche de 2 818 personas y 182 (6,5 por ciento) dieron resultados positivos. De ello se desprende que la prevalencia global de la filariasis de Bancroft no ha disminuido y puede estar aumentando. Las prevalencias fueron más elevadas en los hombres (7,6 por ciento; 91/1 196) así como más alta en las personas de raza negra (7,7 por ciento; 129/1 675) que en las originarias de las Indias Orientales (4,6 por ciento; 34/742). Las prevalencias relativamente altas registradas en niños y adolescentes indican una transmisión activa. Es muy posible que ciertos cambios socioeconómicos y ambientales hayan contribuido a reactivar la transmisión en Georgetown y que lo mismo ocurra en otros lugares de las Américas donde esas condiciones son similares (AU)

Prevalencia de Wuchereria Bancrofti en Georgetown, Guyana / Prevalence of Wuchereria Bancrofti in Georgetown, Guyana

Para calcular la prevalencia de microfilariasis Wuchereria bamcrofti en Georgetown, Guyana, se realizó una encuesta en una muestra aleatoria de la población. Se examinaron frostis de sangre extraída durante la noche de 2 818 personas y 182 (6,5 por ciento) dieron resultados positivos. De ello se desprende que la prevalencia global de la filariasis de Bancroft no ha disminuido y puede estar aumentando. Las prevalencias fueron más elevadas en los hombres (7,6 por ciento; 91/1 196) así como más alta en las personas de raza negra (7,7 por ciento; 129/1 675) que en las originarias de las Indias Orientales (4,6 por ciento; 34/742). Las prevalencias relativamente altas registradas en niños y adolescentes indican una transmisión activa. Es muy posible que ciertos cambios socioeconómicos y ambientales hayan contribuido a reactivar la transmisión en Georgetown y que lo mismo ocurra en otros lugares de las Américas donde esas condiciones son similares (AU)

Disponible en inglés en el Bull PAHO 24(3), 1990

Prevalence of Wuchereria bancrofti in Georgetown, Guyana

A random sample bloodsmear survey was conducted during evening hours in Georgetown, Guyana, to determine the prevalence of Wuchereria bancroftilariae. In all, 182 of 2,818 persons tested (6.5 percent) yielded positive results-indicating that the overall prevalence of Bancroftian filariasis has not dimished and may be on the rise. Relatively high prevalences found in children and adolescents point to active transmission. It appears likely that certain socioeconomic and environmental factors have been contributing to such transmission, and that similar factors could encourage increased transmission elsewhere in the Americas as well. (AU)

Prevalence of Wuchereria bancrofti in Georgetown, Guyana

Published in spanish: Bol. Of. Sanit. Panam Vol.110(1), 1991