Lymphatic filariasis caused by Brugia malayi in an endemic area of Narathiwat Province, southern of Thailand.

Lymphatic filariasis caused by Brugia malayi is highly prevalent in Narathiwat province of Thailand. The World Health Organization has aimed to eliminate the disease globally by the year 2020. To achieve the goal, assessment of the real disease situation should be integrated as part of the control program. The preliminary data for long-term study of the disease situation in this endemic area is necessary for the elimination program of lymphatic filariasis. By using the conventional microscopic method, the microfilarial rate of B. malayi in an endemic area of Narathiwat province was 1.38 per cent. The microfilarial densities ranged from 17 microfilariae/ml to 1,250 microfilariae/ml median = 50. The highest prevalence was found in the age group > 45-60 (4.69%). The lowest microfilarial rate was in the age group < or = 15 (0.37%). The infection in males was about three fold the number in females. A PCR-based method was employed to detect a B. malayi-specific Hha I repetitive DNA sequence with high specificity and sensitivity. The PCR assay will be useful in assisting the elimination program of lymphatic filariasis in control and monitoring the disease in Thailand.

High prevalence of bancroftian filariasis in Myanmar-migrant workers: a study in Mae Sot district, Tak province, Thailand.

Although the prevalence of lymphatic filariasis in the Thai population is low, migration of Myanmar labor into Thailand may increase the incidence of bancroftian filariasis. Epidemiology of filariasis in Myanmars has not been precisely determined. By using microscopic examination, we found that the microfilarial rate in 654 Myanmar migrants working in Mae Sot, Tak province, was 4.4 per cent. The highest microfilarial rate was found in males aged 21-30 years (6.8%). History of mosquito bites was significantly correlated with microfilaremia. The majority of Myanmar migrants (55.5%) have been staying in Thailand 1-6 years; most (82.0%) have never been back to Myanmar. Seventy-nine per cent of infected Myanmars were from Moulmein (Maulamyine) city. Since these migrants carry the parasite with high infected rate and the mosquito vector Culex quinquefasciatus is also prevalent in Thailand, Thai people are at high risk of acquiring this disease if good control and prevention strategies are not implemented.

Eosinophilia, anemia and parasitism in a rural region of northwest Thailand.

Parasitic infections are prevalent in Thailand. The parasites' relationship with anemia and eosinophilia has been rarely reported due to limited health care access, especially in rural areas. We studied the prevalence and relationship between eosinophilia, anemia and parasitism in 169 Thai-Karens from Mae Lamung and Mae Chan subdistricts, Umphang district, Tak Province, using an automated complete blood counter, and microscopic examination for intestinal parasites and microfilaria. In Mae Chan, 5 individuals were microfilaremic, 72% of individuals examined were infected with at least one kind of intestinal parasites, and 50% were anemic, with normal mean red cell volume (MCV). In Mae Lamung, 46% were parasitized (Triteeraprapab et al, 1997) but none were microfilaremic or anemic. In both populations, eosinophilia was prevalent (77%). Hookworm infection was found to be significantly associated with eosinophilia, but not anemia nor microcytosis of red cells.