| Title | Imported Bancroftian Filariasis: Diethylcarbamazine Response and Benzimidazole Susceptibility of Wuchereria bancrofti in Dynamic Cross-Border Migrant Population Targeted by the National Program to Eliminate Lymphatic Filariasis in South Thailand. | | Author(s) | Bhumiratana A, Pechgit P, Koyadun S, Siriaut C, Yongyuth P | | Institution | Department of Parasitology and Entomology, Thailand; Environmental Pathogen Molecular Biology and Epidemiology Research Unit, Faculty of Public Health, Mahidol University, Bangkok 10400, Thailand. | | Source | Acta Trop 2009 Oct 13. | | Abstract | The implementation on the Thailand-Myanmar border of annual mass drug administration (MDA) of a single 6mg/kg dose of diethylcarbamazine (DEC) plus 400mg albendazole, part of the National Program to Eliminate Lymphatic Filariasis (PELF), has been challenging. In particular, chain migration of cross-border Myanmar workers at risk for nocturnally-periodic Wuchereria bancrofti infection can lead to imported bancroftian filariasis (IBF) in Thailand. IBF is targeted for multiple-dose MDA with 300mg DEC, in addition to what is recommended by the World Health Organization (WHO). The dynamic Myanmar migrants in Phang-nga, southern Thailand were sampled to test whether the responsible W. bancrofti has a genetic predisposition of benzimidazole exposure, and IBF exhibits DEC susceptibility. The long-term migrants had more access to DEC. IBF in W. bancrofti antigenemic (microfilaremic vs. amicrofilaremic) short-term migrants exhibited susceptibility to a 300-mg single-dose DEC treatment. During the course of a three-month follow-up, antigenemia was significantly reduced, but microfilaremia fluctuated. Surprisingly, a newly recognized Mansonella infection co-existing among W. bancrofti-affected Myanmar migrants elicited microfilaremia clearance within a month after treatment. As a result of the presence of genetically stable W. bancrofti beta-tubulin (Wbtubb) gene responsible for benzimidazole susceptibility, IBF did not possess a genetic predisposition for benzimidazole exposure. Point mutations at positions Phe167Tyr and Phe200Tyr were not detected by Wbtubb locus-specific nested PCR and sequencing. This study has the potential to help guide not only the Thai/Myanmar PELF surveillance and monitoring of mass treatment impacts on W. bancrofti, but also the other endemic countries allied with the Global Program to Eliminate Lymphatic Filariasis (GPELF). | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19835831 |
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