Border and imported bancroftian filariases: baseline seroprevalence in sentinel populations exposed to infections with Wuchereria bancrofti and concomitant HIV at the start of diethylcarbamazine mass treatment in Thailand
Bhumiratana, A.; Koyadun, S.; Srisuphanunt, M.; Satitvipawee, P.; Limpairojn, N.; Gaewchaiyo, G.
Southeast Asian Journal of Tropical Medicine and Public Health 36(2): 390-407
2005
ISSN/ISBN: 0125-1562 PMID: 15916046 Document Number: 585473
Border bancroftian filariasis (caused by Wuchereria bancrofti) exists in Karens residing alongside the Thailand-Myanmar border, while imported bancroftian filariasis exists in cross-border Myanmar migrants. We analysed seroprevalence data based on W. bancrofti adult worm antigen (Ag) loads and human immunodeficiency virus (HIV) immunoglobulin levels in sentinel populations in Thailand prior to the start of the diethylcarbamazine (DEC) mass treatment during 2002-2006. In 212 Karens, the cumulative infection prevalence (36.8% serological antigen positivity or SAP) was specific for age (p<0.001), but universal for gender (p=0.77). The infection intensity (median Ag load=60 827 antigen units or AU/ml) was specific for age (p=0.031) and for males (p=0.016). In the 221 Myanmar migrants, infection prevalence (24.0% SAP) was universal for age (p=0.961) and for gender (p=0.676). The infection intensity (median Ag load=19 068 AU/ml) was universal for age (p=0.433), but specific for females (p=0.027). Overall, the Ag loads between the groups were significantly different (p=0.014). Seven (3.2%) Myanmar migrants with HIV-1 infection only, and 3 (5.7%) with HIV and W. bancrofti coinfections were subjected to biannual DEC treatment with oral 300 mg DEC. The antigenaemia clearance in patients with coinfections (r=-0.732, p=0.039), and with Bancroftian filariasis only (r=-0.781, p=0.022) was correlated with time required to clear antigenaemia. We emphasize that W. bancrofti adult worm Ag loads in the sentinel populations would be beneficial in evaluating disease burden in target areas, and in evaluating and monitoring the DEC treatment efficacy among Bancroftian filariasis patients, including those with concomitant HIV infection.