STUDIES ON FILARIASIS IN THE REPUBLIC OF THE PHILIPPINES

Blood surveys in the Province of Palawan resulted in prevalence rates of 4.7, 4.2 and 0.8 per cent for W. bancrofti, B. malayi and mixed infection respectively. Malayan filariasis and a very restricted distribution compared to bancroftian filariasis. Males had higher microfilaremia rates than females for both species. Children had higher microfilaremia rates in malayan and lower in bancroftian filariasis. Average microfilarial density was higher in bancroftian than malayan and males had higher microfilarial density than females in the two species. Similar survey in Jolo resulted in a prevalence rate of 11.4 per cent. Atypical microfilariae found together with typical ones, when examined in detail revealed that they were also of W. bancrofti. Microfilaremia rates in makes were higher than in females and rates were higher among older age groups. In Jolo there were more children with microfilaremia compared to Palawan. Extent of abaca plantation and magnitude of filariasis in all municipalities of Jolo showed no correlation, but poblacions located near abaca plantations had higher prevalence rates. Aedes Finlaya poecilus, is the vector of filariasis in Jolo island which confirmed previous finding in Sorsogon, another abaca raising province. Malayan filariasis cases treated with diethylcarbamazine were observed for sie reactions. Fever, joint pains, chilliness and headache were the most common reactions and were directly related to microfilarial density. Culex fatigans and Aedes albopictus were not susceptible to experimental infection with B. malayi whereas Mansonia bonneae showed high infection rates.