Epidemiology and Control of Filariasis in Sri Lanka

• Project/Area Number: 07041170
• Research Category: Grant-in-Aid for international Scientific Research
• Allocation Type: Single-year Grants
• Section: Field Research
• Research Institution: Aichi Medical University
• Principal Investigator: KIMURA Eisaku School of Medicine, Aichi Medical University Professor, 医学部, 教授 (70153187)
• Co-Investigator(Kenkyū-buntansha): WEERASOORIYA M.V. Faculty of Medicine, University of Ruhuna, Sri Lanka, 医学部, 助教授 ; AIRA Yoshikazu School of Medicine, Aichi Medical University, 医学部, 講師 (90210997) ; FUJIMAKI Yasunori Institute of Tropical Medicine, Nagasaki University, 熱帯医学研究所, 講師 (10209083)
• Project Period (FY): 1995
• Project Status: Completed (Fiscal Year 1995)
• Budget Amount: ¥1,500,000 (Direct Cost: ¥1,500,000); Fiscal Year 1995: ¥1,500,000 (Direct Cost: ¥1,500,000)
• Keywords: Wuchereria bancrofti / diethylcarbamazine / Culex quinquefasciatus / permethrin

Research Abstract

1.Microfilaria (mf) positive rate and mf density
Blood surveys for detecting microfilaraemia were carried out in 6 villages in Matara, covering about 5,000 people. Mf positive rates using the thick smearmethod were 7.03% in Matotagama, 7.74% in Hamugewatta, 3.27% in Walgama North, 5.14% in Walgama, 4.53% in Walgama Central and 4.77% in Walgama South, with the average rate of 5.02%. Mf density/60mul of blood was about 30.
2.Filarial circulating antigen
Screening of 500 serum samples for the filarial antigen revealed that the antigen positive rate was nearly twice higher than mf positive rate. Those with antigen and without mf constitute an important group of people whose epidemiological significance has to be clarified.
3.Clinical studies
The prevalence of elephantiasis was 3.2%. The rate was 6-10% at age 55 years and upward. The symptom is by far the biggest public health problem in the study area. Serum samples were collected from clinical cases for immunological studies. Treatment with diethylcarbamazine has been started in parts of the villages and so far 117 mf positives have been treated.
4.Mosquito studies
Out of 18 species of mosquitoes collected in the area, Culex quinquefasciatus was confirmed as the vector of bancroftian filariasis. This mosquito was most abundant in the past 10 months, and filaria infection rates were 0.2-3.3% for mosquitoes caught outdoor and 1.0-4.2% for those caught indoor.
5.Insecticide impregnated curtains
The efficacy of permethrin, lambdacyhalothrin and bendiocarb against Culex quinquefasciatus was compared. They were effective for 22 weeks, and the former two chemicals showed stronger effect than bendiocarb.

Research Products

• [Publications] Kimura,E.and Mataika,J.U.: "Control of lymphatic filariasis by annual single-dose diethylcarbamazine treatments" Parasitology Today. 12〔in press). (1996)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Mataika,J.U.and Kimura,E.: "Are annual single-dose treatments with diethylcarbamazine effective at very high microfilaria rates and densities?" Bulletin of the World Health Organization. 74(accepted). (1996)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Mitsui,Y.,tanimori,H.,Kitagawa,T.Fujimaki,Y.and Aoki,Y.: "Simple and sensitive enzyme-linked immunosorbent assay for ivermectin" American Journal of Tropical Medicine and Hygiene. 54〔in press). (1996)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Mitsui,Y.,Takamura,N.,Fujimaki,Y.,Yamaguchi,T.,Kitagawa,T.and Aoki,Y.: "Development of a competitive enzyme-linked immunosorbent assay for diethylcarbamazine" Tropical Medicine and International Health. 1 (in press). (1996)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Weerasooriya,M.V.,Munasinghe,C.S.,Mudalige,M.P.S.,Curtis,C.F.and Samarawickrema,W.A.: "Comparative efficacy of house curtains impregnated with permethrin,lambdacyhalothrin or bendiocarb against the vector of bancroftian filariasis,Culex quinquefasciatus Say in Matara." Transactions of the Royal Society of Tropical Medicine and Hygiene. 90 (in press). (1996)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Kimura, E.and Mataika, J.U.: "Control of lymphatic filariasis by annual single-dose diethylcarbamazine treatments" Parasitology Today. 12 (in press). (1996)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Mataika, J.U.and Kimura, E.: "Are annual single-dose treatments with diethylcarbamazine effective at very high microfilaria rates and densities?" Bulletin of the World Health Organization. 74 (accepted). (1996)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Mitsui, Y., Tanimori, H., Kitagawa, T., Fujimaki, Y.and Aoki, Y.: "Simple and sensitive enzyme-linked immunosorbent assay for ivermectin" American Journal of Tropical Medicine and Hygiene. 54 (in press). (1996)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Mitsui, Y., Takamura, N., Fujimaki, Y., Yamaguchi, T., Kitagawa, T.and Aoki, Y.: "Development of a competitive enzyme-linked immunosorbent assay for diethylcarbamazine" Tropical Medicine and International Health. (in press). (1996)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Weerasooriya, M.V., Munasinghe, C.S., Mudalige, M.P.S., Curtis, C.F.and Samarawickrema, W.A.: "Comparative efficancy of house curtains impregnated with permethrin, lambdacyhalothrin or bendiocarb against the vector of bancroftian filariasis, Culex quinquefasciatus Say in Matara." Transactions of the Royal Society of Tropical Medicine and Hygiene. 90 (in press). (1996)
  • Description: 「研究成果報告書概要(欧文)」より