Read this article to learn about the use of transgenic organisms for the control of various diseases.
Several human diseases have a second host in the life cycle of the parasite. Trans-genesis will be useful for disease control by interrupting the life cycle.
Attempts are being made in the recent years in this direction, although the success has been limited. Transgenic organisms may soon serve as environmental replacements to control several diseases.
Transgenic Snails:
Schistosomiasis is a parasitic diseases caused by Schistosoma which develops in the snails. The parasite infects humans by penetrating through skin when contacted in water. It is estimated that about 100 million people worldwide are the victims of schistosomiasis. This disease is characterized by chills, fever, intestinal ulcerations and diarrhea.
By developing transgenic snails, it is possible to interrupt the life cycle of Schistosoma. Some workers have attempted to create transgenic snails that will resist the invasion of the parasite. If such snails are released into the environment, they will break the life cycle of schistosoma.
Transgenic Mosquitoes:
Mosquitoes are responsible for the transmission of malaria. Some workers have identified certain critical genes in mosquitoes (Anopheles genus that transmits Plasmodium species malarial parasite) that are responsible for harbor and transmission of the parasite. Theoretically, it is possible to alter these genes and produce transgenic mosquito. If such mosquitoes are released into the environment in large numbers, they will dilute the population of native mosquitoes, and halt the transmission of malarial parasite.
Another approach to control malaria is to understand vector incompetence i.e., the genetic basis of the vector to sustain a parasite and how to alter it so as to make the vector inhospitable for the parasite. Some success has been achieved in developing transgenic mosquitoes with vector incompetence. If such mosquitoes are released into the environment, the life cycle of the malarial parasite will be interrupted.
Transgenic Tsetse Flies:
A protozoal disease African sleeping sickness is transmitted by tsetse fly. This disease affects the nervous system and is often accompanied by coma. Transgenic tsetse flies were developed with a novel approach. Researchers found a protein that can kill disease-producing protozoa. They identified the protein encoding gene and inserted it into the bacteria of tsetse fly gut. These bacteria produce antiprotozoal protein that kills tsetse flies. In this manner the disease transmission can be prevented.
Transgenic Bollworms:
Bollworms are the caterpillars that damage the cotton crop. Researchers have developed transgenic bollworms with a suicide gene. When released into the environment, the transgenic bollworms will mate with wild bollworms and produce caterpillars that die. The cotton crop can be saved from the damage.
Transgenic Medflies:
Medflies (Mediterranean fruit flies) destroy fruit and coffee crops throughout the world. Attempts are being made to develop transgenic medflies to replace wild medflies and save the crops.