Diseases – Major Zoonoses



Brucellosis

Brucellosis is an infectious disease caused by the bacterium Brucella. It is spread by animals, most commonly sheep and goats. It has been almost completely eliminated from many developed countries, but is common elsewhere. It can produce a flu-like illness in humans that is often severe (with cough, muscle aches and bone pain) that may go on to affect the heart or nervous system, or it may become chronic and relapsing with non-specific tiredness and fatigue. Humans are most commonly infected by consumption of unpasteurised milk or milk products, or by contact with infected animals. Further information on brucellosis can be found here:

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Campylobacter

Campylobacteriosis is the commonest form of bacterial gastroenteritis in Ireland. It is caused by a bacterium known as Campylobacter. Campylobacter is generally contracted from contaminated food and water. Further information on Campylobacter can be found here:

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Cryptosporidiosis

Cryptosporidiosis is a diarrhoeal disease caused by a microscopic parasite, Cryptosporidium. Once an animal or person is infected, the parasite lives in the intestine and is passed on through the stools. In healthy adults, it tends to produce unpleasant but mild disease, but in small children and immunocompromised adults the illness can be more protracted and severe. Further information on Cryptosporidiosis can be found here:

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Salmonella

Salmonellosis is a common form of gastroenteritis infection caused by a bacterium called Salmonella. Salmonellae are passed from the faeces of people, or animals, to other people or other animals; most cases of human salmonellosis are contracted by contact with contaminated food and food products. There are over 2000 different types of Salmonella and the illness produced tends to be mild and self limiting but severe disease leading to dehydration and even death is not unknown. Salmonella Enteritidis and Salmonella Typhimurium are the commonest in Ireland. Further information on Salmonella can be found here:

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Toxoplasmosis

Toxoplasmosis is a parasitic disease caused by Toxoplasma gondii which generally produces mild disease in humans but can lead to severe disease in unborn babies and patients with weakened immune systems. Although all animals and birds can be infected with Toxoplasma, the primary hosts are members of the cat family. Further information on toxoplasmosis can be found here:

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Tuberculosis

Tuberculosis or "TB" is a disease caused by bacteria known as Mycobacteria. Tuberculosis usually affects the lungs but it can also affect other parts of the body including the glands, the bones and rarely the brain. The commoner type, pulmonary (or lung) tuberculosis, is caused by Mycobacterium tuberculosis. Another form, Mycobacterium bovis, is found in cattle and can infect humans through consumption of contaminated milk. Further information on tuberculosis can be found here:

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VTEC

VTEC is a type of E. coli bacterium. Most E. coli are relatively harmless, or produce only mild disease, and are found in the intestines of healthy humans and animals. VTEC, on the other hand, produces a powerful toxin (similar to that produced by shigella in cases of dysentery) and can cause severe illness, especially in elderly people and smaller children. Further information on VTEC can be found here:

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What are Zoonoses