TANZANIA FILARIASIS PROJECT - PROVOCATIVE DAY TEST WITH DIETHYLCARBAMAZINE FOR THE DETECTION OF MICROFILARIAE OF NOCTURNALLY PERIODIC WUCHERERIA-BANCROFTI IN THE BLOOD

  • 1 January 1979
    • journal article
    • research article
    • Vol. 57  (5) , 759-765
Abstract
In coastal Tanzania, an area where the microfilariae (mf) of W. bancrofti exhibited nocturnal periodicity, the administration of 2 mg diethylcarbamazine (DEC)/kg body wt in the daytime provoked mf to enter the peripheral blood. In persons on normal daily activities the daytime DEC provocative method proved as sensitive in detecting microfilaremia as the examination of night blood. Its use in routine surveys was justified. Although mf densities by day and night were highly correlated (r = 0.83) they tended to be lower provocative daytime DEC than in the corresponding night blood, except in very light infections. This method was useful in assessing the parasitological response to mass chemotherapy with DEC, but, in comparison with the results of the night blood examinations, the sensitivity and magnitude of the counts in persons remaining positive progressively decreased as the period of DEC administration increased. A correction factor must be calculated and/or additional night blood samples must be taken. The dose of 2 mg of DEC/kg body wt used was readily acceptable to the people in coastal East Africa, whose cooperation was difficult to obtain for night blood surveys. Apart from W. bancrofti, the only human filarial infection occasionally encountered in this area was Dipetalonema perstans. Because of the risk of a severe Mazzotti reaction the test was contraindicated in onchocerciasis endemic regions. Severe reactions might occur in subjects with loaiasis.