Tolerability and efficacy of single dose diethylcarbamazine (DEC) alone or co-administration with Ivermectin in the clearance of Wuchereria bancrofti microfilaraemia in Pondicherry, South India.

The tolerability and efficacy of single dose DEC (12mg/kg body weight) or co-administration of DEC (6mg/kg body weight) with Ivermectin (200 or 400 mcg/kg of body weight) was studied in 60 asymptomatic W. bancrofti microfilariae (Mf) carriers following a double blind randomized design. The drugs were tolerated well. The incidence of adverse reactions of DEC (85.0%), DEC + Ivermectin 200mcg (95.0%) and DEC + Ivermectin 400mcg (100%) did not vary significantly (P>0.05). The mean score of adverse reaction intensity due to DEC + Ivermectin 200mcg (1.41) was significantly higher compared to DEC (0.61) (P<0.05). However, there was no significant difference between and DEC +Ivermectin 400mcg (0.89) and DEC + Ivermectin 200mcg (1.41) and DEC + Ivermectin 400mcg and DEC. The major adverse reactions were fever, headache and myalgia in all groups. The incidence and intensity of the adverse reactions were maximum between 24 to 48 hours of post therapy. The haematological and biochemical parameters did not vary significantly between pre and 7-day post therapy values in any of the study groups (P>0.05). Efficacy was measured in terms of proportion of cases clearing microfilaraemia completely and reduction in geometric mean parasite density in comparison to pre therapy levels. At the end of one year, DEC with Ivermectin 400mcg group showed significantly higher efficacy in complete clearance of Mf (94.4%) than that of DEC with Ivermectin 200mcg (60.0%) or DEC alone (52.6%) (P<0.05). However, no significant difference was observed in reduction of geometric mean Mf density (99.9%, 99.7%, 99.5% respectively). In all the groups, the tolerability and efficacy of the drugs were independent of host age and gender.

The preferential site of adult Wuchereria bancrofti: an ultrasound study of male asymptomatic microfilaria carriers in Pondicherry, India.

BACKGROUND: The traditional method of detection of microfilaria in night blood specimens for the diagnosis of Wuchereria bancrofti infection is being replaced with circulating filarial antigen in day blood specimens, which has a high sensitivity. However, both methods are indirect tests to detect the presence of adult worms in vivo. Localization of adult worms in vivo in their natural habitat may help in understanding better the end-point of drug treatment, the adulticidal action of antifilarial drugs, and in locating the site of lymphatic pathology. We used ultrasound examination to assess the preferential location of adult worms in an area endemic for lymphatic filariasis. METHODS: Ultrasound examination was done in 36 asymptomatic male carriers of Wuchereria bancrofti microfilaria to detect the location of adult worms. Both sides of the scrotum (root of the scrotum, epididymis, spermatic cord, testis and the adjoining area), lymphatic vessels and inguinal, popliteal, axillary and epitrochlear lymph nodes were examined using a 7.5 MHz probe in real-time B mode. RESULTS: The 'filaria dance sign (FDS)' suggesting the presence of adult worms was observed in 22 carriers (61%). The preferential site of location of the adult worms was the intrascrotal juxtatesticular lymphatic vessels in 'nests' along the lymphatic vessels of the epididymis, spermatic cord and paratesticular region. The number of nests varied between 1 and 4 with a mean size of 0.3 cm2. In 95% of cases, localization of the worms was unilateral. The mean microfilaria (SD) count-positive cases for those with the filarial dance sign (264 [199]) was significantly higher (p<0.05) than for the negative cases (171 [196]). CONCLUSION: Ultrasound visualization of adult worms of Wuchereria bancrofti in vivo is possible and confirms the concept that the worms have their own territory and reside in 'nests'. The preferential site of localization of the adult worms in men is the intrascrotal juxtatesticular lymphatic vessels.