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.