Diseases Spread by Insects or Other Carriers:
We know malaria is transmitted by the female Anopheles mosquitoes. Dengue fever and filaria are also caused by mosquito's bite. These insects suck blood and also inject some of it back into the body. Mosquitoes get the germs by sucking the blood of someone suffering from the disease, and transmit them to others when they puncture their skin or '!bitem them. Houseflies are also caniers of germs of intestinal diseases. Simparly many fleas also spread diseases. Rats are reservoir of many diseases. Innumerable. outbreaks of plague were caused by them. Lice, ticks, cockroaches, etc. also carry germs of various diseases. Guinea worm disease is quite common in India. The adult worm is about a metre long and it migrates from the stomach to the leg and produces larvae which are released in water as shown in Fig.