The research activities are concentrated on filariasis and schistosomiasis which constitute the major public health problems in the tropics.

Filariasis
　　Brugia malayi（Cheju strain, periodic form）, B. pahangi and the vector mosquito, Aedes aegypti (Liverpool strain）have been maintained in the laboratory for many years. Highlights of recent studies are as follows.
１）Mode of action of diethylcarbamazine （DEC） :
　　Recently we reported that DEC is a competitive inhibitor of acetylcholinesterase of filarial worms, DEC inhibits cell proliferation, disrupts the microtubules of LLC‐MK２ cells, inhibits polymerization of microtubules and disrupts the pre‐formed microtubles in vitro.
２）Development of a simple and sensitive method for determination of serum concentration of ivermectin （IVM）and DEC:
　　IVM and DEC modified partially in their chemical structure successfully produced the antibody against drugs. Therefore the serum concentration　（５ ng/ml）of IVM and DEC can be determined by EIA.
３）Combination of DEC and IVM for the treatment of filariasis:
　　Several lines of evidence indicate that DEC and IVM interact additively or synergistically against microfilariae and adult worms of B. pahangi in vivo and in vitro.
４）Screening of antifilarial drugs from medical plants:
　　Vernonia amygdalina from Africa, Neurolaena lobata from Guatemala and Cardiospermun halicacabum from Thailand were effective in vitro on B. pahangi adult worms and microfilariae.
５）Epidemiology and control of bancroftian filariasis:
　　A research project was carried in Kwale, Kenya, in cooperation with Kenya Medical Research Institute（KEMRI）during the period of １９９０ and １９９６．Transmission potential and morbidity were studied. Mass‐chemotherapy with combination of DEC and NaHCO_３ was evalualed.

Schistosimoasis
　　Schistosoma mansoni（Puerto Rican strain and Kenyan strain）, S. haematobium （Kenyan strain）and some strain of vector snails have been maintained in the laboratory. Highlights of recent studies are as follows.
１）Swimming behavior of miracidia:
　　cAMP is involved in the control of ciliary beating and chemotaxis of miracidia.
２）Mechanisms of penetration of cercariae into skin:
　　The studies suggest the involvement of protein kinase C in proteolytic enzyme release from cercariae.
３）Epidemiology and control of S. haematobium infection:
　　Since １９８１， the research project on Schistosomiasis haematobia was carried out in Kwale, Kenya, in cooperation with KEMRI for １５ years. The highlights of our studies are human water contact study, cercarial concentration in natural water, ecology of Bulinus globosus, usefulness of urinary reagent strips, new immunodiagnostic test（urine ELISA, modified COPT）, effect of piped water supply, KAP study（knowledge, attitute and practices）, health education, morbidity studies using ultrasound and environmental modification for snail control.
Recently high prevalence of bladder cancer and liver fibrosis is reported in the community.