Zoonoses are defined as infections which are naturally transmitted between animals and people. Because of the risk to their own health, people handling animals need to know about such diseases and the precautions they must take to minimise the risk of infection.
Leptospirosis or “lepto”, is the most well-known zoonosis in New Zealand (NZ) agriculture and one of the most widespread occupationally acquired zoonoses in the world. NZ has high infection rates, with around 100 cases reported (60% requiring hospitalisation) each year, but it is estimated that 40-50 times more cases go unreported. Despite years of vaccination in cattle, 30% of dairy herds have cows passing lepto in their urine. Urine from pigs, sheep, deer, rodents and wild animals can also be a source of infection.
Cryptosporidiosis is a common cause of calf scours and is transmitted to humans by direct contact with animal faeces, or contamination of water or food. Good sanitation and hygiene are essential when handling calves.
Campylobacter exists in the gastro-intestinal tract of ruminants, poultry and other domestic animals causing them no harm. These animals are the sources of most human infections. Humans are infected via the oral route, with the infective dose being relatively low. It causes diarrhoea with abdominal cramps.
Salmonellosis in humans is a gastro-intestinal infection associated with contact with infected faeces. Some types of Salmonella cause disease in calves and mature cattle, though many animals may carry Salmonella without showing signs. Salmonella can multiply in many food products kept at room temperature. Therefore salmonellosis is often a food-transmitted disease.
Ringworm is a fungal infection common in young cattle and is easily transmitted to humans. Practice good hygiene when working with ringworm infected stock. Cats, dogs, horses, sheep and rodents are also susceptible and possible sources of human infection.
Any people who have close contact with animals need to maintain stringent cleanliness and hygiene standards and vaccinate where possible, such as for leptospirosis, in order to protect themselves and those around them from these potentially debilitating diseases.