Wuchereria bancrofti in Kwale District, Coastal Kenya: patterns of focal distribution of infection, clinical manifestations and anti-filarial IgG responsiveness.
A cross-sectional study of bancroftian filariasis was conducted in 2 adjacent communities, Mvumoni and Kilore in Muhaka, Kwale District. Wuchereria bancrofti infection, clinical manifestations and anti-filarial IgG responsiveness were determined before the long rains, a time coinciding with a low transmission season. The prevalence of microfilaraemia increased gradually with age and was significantly higher in Kilore (24%) than in Mvumoni (6.3%, P < 0.001). Similarly, the prevalence of antigenaemia increased with age and also was significantly higher in Kilore, 48.9% than in Mvumoni, 20.5% (P < 0.001). Hydrocele, funiculitis, lymphangitis and lymphadenitis were also significantly more common in Kilore than in Mvumoni. In comparing the 2 communities, levels of IgG4 responsiveness in antigen-positive persons were higher in Kilore than Mvumoni (P = 0.034), but this was related to higher antigen loads in persons in Kilore than in Mvumoni. In antigen-negative persons, anti-filarial antibodies of 3 IgG isotypes were significantly higher in Kilore than Mvumoni (P < 0.001, for IgG1, IgG2, IgG4). These results emphasize the highly focal nature of bancroftian filariasis in this setting and demonstrate that anti-filarial antibody levels are related to transmission intensity.
Wamae
C N
CN
Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya. KemriLib@ken.healthnet.org
Gatika
S M
SM
Roberts
J M
JM
Lammie
P J
PJ
D000293:Adolescent; D000328:Adult; D000351:Africa, Eastern / Q000453:epidemiology; D000367:Age Factors; D000368:Aged; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood*; D000947:Antigens, Helminth / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005368:Filariasis / Q000453:epidemiology* / Q000469:parasitology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D018512:Parasitemia / Q000453:epidemiology* / Q000469:parasitology; D018709:Statistics, Nonparametric; D014958:Wuchereria bancrofti / Q000276:immunology*
D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D007074:Immunoglobulin G