Wuchereria bancrofti infection in human and mosquito populations of a Polynesian village ten years after interruption of mass chemoprophylaxis with diethylcarbamazine.
In 1991, a study on Wuchereria bancrofti microfilariae (mf) and infection rates was carried out in the human and mosquito populations of a Polynesian village where, 10 years before, the mf prevalence rate was 6.4% and twice-yearly mass treatment with 3 mg/kg of diethylcarbamazine (DEC) was interrupted. Venous blood samples were collected from 575 (97%) individuals aged 15 years or more, of whom 122 (21.4%) were mf positive. The mf carrier prevalence rate was 27.4% in males, significantly higher than that of 14% in females; it increased from 7-12% in the youngest age group (15-19 years) to 40-50% in the oldest (> or = 60 years) for both males and females. 387 mosquito collections were performed and 1748 female Aedes polynesiensis were dissected, of which 1176 were parous. Among the latter, 114 (9.7%) were infected with Wuchereria bancrofti larvae at L1, L2 or L3 stages. The mean number of larvae per mosquito was 2.46 (range 1-15). Of the 114 infected mosquitoes, 30 harboured L3 larvae, giving a 2.55% infective rate; the mean number of L3 larvae per mosquito was 1.15 (range 1-2). Such findings indicate that the interruption of systematic twice-yearly mass treatment with DEC (3 mg/kg) has resulted, after 10 years, in a substantial increase of microfilarial prevalence in humans, and in high infection rates in mosquitoes.
Cartel
J L
JL
Institut Territorial de Recherches Medicales Louis Malardé, Papeete, Tahiti, Polynésie Française.
Nguyen
N L
NL
Spiegel
A
A
Moulia-Pelat
J P
JP
Plichart
R
R
Martin
P M
PM
Manuellan
A B
AB
Lardeux
F
F
D000293:Adolescent; D000328:Adult; D000330:Aedes / Q000469:parasitology*; D000368:Aged; D000818:Animals; D002353:Carrier State / Q000453:epidemiology / Q000469:parasitology; D004049:Diethylcarbamazine / Q000627:therapeutic use*; D004605:Elephantiasis, Filarial / Q000453:epidemiology / Q000469:parasitology* / Q000517:prevention & control; D005260:Female; D006801:Humans; D007303:Insect Vectors; D008297:Male; D008875:Middle Aged; D011114:Polynesia / Q000453:epidemiology; D015995:Prevalence; D012737:Sex Factors; D013997:Time Factors; D014958:Wuchereria bancrofti / Q000302:isolation & purification*
D004049:Diethylcarbamazine