Rapid Assessment for Lymphatic Filariasis in Central Nigeria: A Comparison of the Immunochromatographic Card Test and Hydrocele Rates in an Area of High Endemicity

Abstract

The rapid immunochromatographic card test (ICT) for Wuchereria bancrofti circulating filarial antigen is being used to map areas endemic for lymphatic filariasis. However, the ICT is expensive; thus, surveys based on this test must be relatively limited. Our study was conducted to determine if village-based hydrocele surveys could be used to supplement the ICT surveys in the mapping activities. We compared in 144 Nigerian villages the two assessment methods, ICT and examination for clinical hydrocele, in random samples of 30 adults selected using a procedure that obtained 15 younger males (reported age ‫ס‬ 16−39 years old) and 15 older males (Ն 40 years), based on the assumption that hydrocele rates may be more prevalent in older age groups. The men were asked if they had scrotal swelling, then examined and tested by the ICT. We found a weakly positive correlation between village prevalence determined by the ICT and hydrocele (r ‫ס‬ 0.041, P < 0.001). Only villages with hydrocele rates of 20% or greater were also consistently classified as having endemic filariasis by the ICT. There was no correlation between an individual's ICT positivity and clinical presence of hydrocele, and questioning about scrotal swelling was not predictive for presence of hydrocele. More research is needed to determine if community level hydrocele prevalence surveys can offer an economical and broadly applicable supplement to the ICT for determining the endemicity of filariasis.

Status of lymphatic filariasis in Afikpo North L.G.A., Ebonyi State, Nigeria

“…Subjects within 73 years and above had no circulating filarial antigen of W. bancrofti in their blood. Eigege et al, (2002) had a similar result in Lafia, Nasarawa State, Nigeria. Also the prevalence of W. bancrofti microfilariae using the Knott's Concentration Techniques shows that subject within the age group 58-62 years had the highest percentage prevalence of 26.09% for male and 18.18% for females.…”

“…Njenga and Wamae (2001) in Nairobi, Kenya, they established a higher prevalence rate of 37.3% of lymphatic filariasis, using the ICT method, as against 21.13% recorded in this work, using the ICT method also. Eigege et al, (2002) reported a similar prevalence rate of 22.6% using the ICT method in Lafia, Nasarawa State, Nigeria, just as established in this work 21.13% in Afikpo North L.G.A. Ebonyi State.…”

Ongoing Surveillance for Lymphatic Filariasis in Togo: Assessment of Alternatives and Nationwide Reassessment of Transmission Status

“…Although the current report focuses on surveillance to ensure interruption of transmission, morbidity control efforts have also been an essential component of the LF control program in Togo and have recently been described elsewhere. 6,24 Because hydrocele and lymphedema are poor indicators of active filarial burden, 25 they are not currently used for surveillance of LF transmission in Togo; incorporation of these indicators of LF-related morbidity into ongoing surveillance should be considered.…”

Evidence for Stopping Mass Drug Administration for Lymphatic Filariasis in Some, But Not All Local Government Areas of Plateau and Nasarawa States, Nigeria

“…6 Baseline LF mapping using rapid blood antigen detection tests showed mean local government area (LGA) prevalence of 23% (range 4-62%) among persons 15 years of age and older in 70 randomly selected sites in the two states. 7,8 Since 2000, health education plus MDA using 150 μg/kg of ivermectin (Mectizan ; donated by Merck & Co., Inc., Whitehouse Station, NJ) and 400 mg of albendazole (donated by GlaxoSmithKline, Brentford, Middlesex, UK) have been implemented annually according to WHO guidelines to eliminate LF transmission, using each LGA as an independent MDA implementation unit. A phased LGA scale-up to implementing MDA was adopted in the two states as capacity of the program increased and by 2003 all 30 LGAs within the states were under MDA interventions.…”