A zoonosis is a disease that can be transmitted from animals to people. There are many of these, and you will be familiar with the theory that Covid transferred to people from bats, but only a few that you are at genuine risk of from cattle. Most of them are excreted in faeces, so hygiene and PPE are important in keeping yourself healthy. As with Covid, frequent washing of your hands is a critical step in keeping yourself low risk for most of these diseases:


Leptospirosis is the disease every farm should vaccinate for. It is caused by bacteria (leptospires) which can be carried by cattle and sheep even if they look healthy. The bacteria colonize the kidneys, which means it is spread via urine. Even tiny droplets can gain access to the human body via mucous membranes (mouth, eyes, nose) and cuts to the skin. If you can smell urine you can catch it! It can also be caught from contaminated effluent, stagnant water etc. so be aware of water-borne transmission via ponds etc.


  • Cattle – redwater, abortion, generally unwell
  • People – flu like symptoms, aches, pains, fever/chills, Nausea/vomiting/diarrhoea. Some people will be more seriously affected, and may need to be hospitalised due to Liver damage, Kidney failure, Brain swelling, Heart failure

Treatment – hospitalization, antibiotics


  • Hygiene – it is really important that you do not smoke, eat or drink during milking as this is a great way to introduce the infection. Gloves should be worn and other PPE as appropriate. Hands should be washed regularly. These precautions should also be applied when hosing effluent in shed and yard, and calving cows / handling membranes. Cuts and scratches should be covered with waterproof plasters.
  • Ponds and waterways should be fenced off from stock. Effluent should not be spread in wet conditions, leptospires can last for 6 months, and pasture should not be grazed until effluent has dried. Prevent effluent and water settling especially near the shed by clearing drains, culverts etc.
  • Pest control – rats can also carry lepto, ensure there is a policy
  • Pigs – don’t have them, or vaccinate them and keep effluent contained
  • Dogs should be vaccinated
  • Vaccination – the national vaccination strategy has reduced the incidence of leptospirosis in dairy cows and farmers (although beef and abattoir workers are still at risk). Calves need 2 injections for the primary course, thereafter most animals get a booster in the winter. There are many strains or types of lepto, but the vaccine covers the most common ones.



Salmonella is another well known disease which can be caught from animals and can be vaccinated for.

Again it is a bacterial infection which can be carried by apparently healthy animals, but this one is spread in the faeces not the urine. It Lives in the guts of many species, and can cause bloody diarrhoea, milk drop and death.
It can affect both calves and adult cattle.

Prevention is by vaccination of the herd, and personal hygiene. Wearing gloves and washing hands are not just useful for covid! Again there are multiple strains, and birds can carry it too, but cow effluent / calf scours are the biggest risks. Contaminated and improperly cooked poultry is also a risk.

Treatment is generally antibiotic injections.


Ringworm is actually a fungal infection like athletes foot! In cattle it is highly contagious and can spread rapidly within a mob, particularly youngstock. Generally, the cow’s immune system gets rid of it after a few months, but it looks unsightly. Kittens are also a common source of ringworm spreading to children as they cuddle them. Cattle show multiple grey, flat, hairless circles on the head and neck. Direct transfer from a cow can leave a person with the classic scaly round lesions on your arms with a red edge. If you suspect it, tell your doctor you work with animals.

Treatment for people is an anti-fungal cream or tablets, but we do not treat cattle.

Prevention is…awareness and hygiene!

Raw milk

Raw milk is growing in popularity, but it has its risks, which are reduced simply by pasteurization:

Salmonella, E. coli, Listeria, Campylobacter

Campylobacter is also a bacterium which is spread in the faeces. Many healthy cows shed it, and it can be a cause of calf scours. Food poisoning may also be a cause of campylobacteriosis in people. It causes abdominal cramping and severe diarrhoea.

Prevention is…hygiene! Disinfection of calf pens and feeding utensils.

Listeria is particularly a risk for pregnant women or people with weak immune systems. It is a food-borne infection which can cause fever, aches and pains, nausea, diarrhoea, vomiting, miscarriage, stillbirth, meningitis or death. Riskier foods are uncooked meat/ fish, pre-cooked processed meat, raw milk / dairy products, soft cheeses etc.. Prevention is to avoid these foods when pregnant, ensure all food is thoroughly cooked, wash vegetables and hands, refrigerate left-over food immediately and reheat very well.

E.coli O157 and VTEC are bacteria which can cause severe diarrhoea and cramps and vomiting and even organ damage. Although it is spread in effluent, this can include contaminated vegetables or undercooked meat.

TB or Tuberculosis – most human TB is not from cattle, but it is possible. Cattle in NZ are routinely tested for TB and we are essentially TB free in this area. Signs are a persistent cough, fever and weight loss. It can be contracted by aerosol droplets, hand-to-mouth, drinking raw milk.

Cryptosporidia are protozoa parasites which are excreted in the faeces. They can cause calf scours, and can do the same to people especially children and immunocompromised. Wash fruit and veges! Keep  children out of the (sick) calf sheds 

Giardia is a protozoa which causes diarrhoea, often caught from contaminated water

Yersinia is a bacterial infection which is often seen in weaner calves causing weight loss and diarrhoea. Like Salmonella, people can also catch it.

Hydatids – Echinococcus is a canine tapeworm which is shed in their faeces. It can then go on to infect sheep or people, where it forms cysts in the liver, lungs, heart or brain. Dogs can catch it from eating infected sheep, so cooking meat before feeding it to dogs, disposal of sheep carcasses promptly and appropriately, and worming farm dogs regularly is also important. NZ Free since 2002 

Toxoplasmosis is a parasite that can infect sheep and cats. It is mostly only a problem for pregnant women or the immunocompromised. It can be spread to people during assisting lambing sheep or by eating food contaminated with cat poo. Wash your vegetables, cook meat, wear gloves if lambing! Change cat litter regularly and hygienically. Pregnant women should avoid lambing sheep.

Vision can be affected causing blurred vision or a “floater” in the eye.

It can affect the unborn child causing physical defects, stillbirth, abortions.