Molecular Biological Approaches to Filariasis

Filariasis in Sri Lanka is caused by the filarial nematode parasite, Wuchereria bancrofti. The disease is transmitted by the vector mosquito, Culex quinquefaciatus. According to WHO data, currently more than 125 million people in tropical countries of the globe are infected. In the past few years we have been successful in the development of rapid and highly sensitive DNA based diagnostic techniques and also similar DNA based methods to detect the vector mosquito.

There are only two drugs presently available for the treatment of the disease, carbamazine and ivermectin. There is, therefore a great need to develop new drugs and identify potential drug targets in the parasite. The enzyme, cyclo-oxygenase, in the parasite has been hypothesized as a potential target for drug development. Partial purification and characterization of this enzyme was completed.

The filarial parasite Wuchereria bancrofti causing lymphatic filariasis cannot be cultured. Only source of parasite material is from night blood samples collected from patients. This source is not sufficient to undertake molecular studies. A related cattle filarial parasite is Setaria digitata. The adult worm of this parasite can be obtained in large quantities from the abdominal cavity of cattle slaughtered at abattoirs. Using this parasite a cDNA library was established. The screening of this library for parasite specific genes is being continued and myosin light chain gene and several other genes have been sequenced. These are likely to provide potential diagnostic methods or therapeutic targets for the development of new drugs for filariasis.

A Probationary Lecturer in Parasitology at the Faculty of Medicine, University of Jaffna carried out MPhil studies under this project. DNA sequences generated are providing the basis for an MPhil degree registered at University of Colombo, School of Computing.

Related studies are being carried out by a student registered at the Faculty of Science for MPhil degrees. This project aims to study function of nematode specific proteins from the cattle filarial parasite Setaria digitata and to study its organelle localization. Experiments are conducted at the Institute of Biochemistry, Molecular Biology and Biotechnology (IBMBB).