Zoonosis

Overview :

Although many diseases are species specific, meaning that they can only occur in one animal species, many other diseases can be spread between different animal species. These are infectious diseases, caused by bacteria, viruses, or other disease causing organisms that can live as well in humans as in other animals. There are different methods of transmission for different diseases. In some cases, zoonotic diseases are transferred by direct contact with infected animals, much as being near an infected human can cause the spread of an infectious disease. Other diseases are spread by drinking water that contains the eggs of parasites. The eggs enter the water supply from the feces of infected animals. Still others are spread by eating the flesh of infected animals. Tapeworms are spread this way. Other diseases are spread by insect vectors. An insect, such as a flea or tick, feeds on an infected animal, then feeds on a human. In the process, the insect transfers the infecting organism. The Centers for Disease Control (CDC) in Atlanta have said that most emerging diseases around the world are zoonotic. The director of the CDC has said that 11 of the last 12 emerging infections in the world with serious health consequences has probably arisen from animal sources. Wild animal trade occurs across countries and many people take in wild animals as domestic pets. However, pet shops and food markets are not properly testing for diseases and parasites that can cause harm to humans and other animals. Some zoonotic diseases are well known, such as rats (plague), deer tick (Lyme disease). Others are not as well known. For example, elephants may develop tuberculosis, and spread it to humans.