16 Zoonotic Diseases of Cows (Bovine Zoonoses)

There are around one billion cows on the planet. They use up a lot of land, feed and water, and they produce a lot of climate-damaging methane. Farming, exploiting and eating these gentle animals can also cause serious illnesses in people. Read on for 16 ways we hurt ourselves when we hurt cows.

What Are Zoonotic Diseases?

Zoonotic diseases are caused by germs that spread between animals and people – bacteria, viruses, parasites and protozoa. They may affect just the person who comes into direct contact with those germs or they can spread from person to person as an infectious disease. Some cause mild symptoms, others can be deadly.

Historically, we invited many illnesses into the human population when we started domesticating and farming animals: Tuberculosis, measles, whooping cough, typhoid, leprosy, and the common cold, for example. Despite these warnings from the past – which still blight people’s lives today – there have been many more recent diseases caused by our exploitation of animals: Avian flu, swine flu, SARS, MERS, AIDS, Ebola and Covid-19.

How Can Zoonotic Diseases be Transmitted to Humans?

Infectious agents may be passed through direct physical contact with animals. This can be by being bitten or scratched, or by coming into contact with infected skin, wounds, saliva, urine or feces.

But we don’t have to come into direct contact with animals to become infected. They may cough or sneeze infectious droplets out into the world that then contaminate surfaces or objects nearby. Pathogens may also be carried by insects and transmitted to people through a bite. And, of course, we can put those pathogens directly into our own bodies when we eat contaminated foods.

What Animals Carry Zoonotic Diseases?

Every animal carries pathogens of some kind. Many of these will bring about mild symptoms, some will bring about severe symptoms, and some live harmlessly inside them, quite unnoticed. But what is harmless to one animal may prove deadly to people because we have no immunity to that particular pathogen.

Just as fifteenth-century white settlers took pathogens to the Americas and wiped out huge numbers of indigenous people who had no immunity to them, so the same happens when we force close contact with animals. We hunt, kill, capture, cage, trade, incarcerate, slaughter, and butcher them, and as we do that, we acquire their diseases.

16 Zoonoses Associated with Cows


Anthrax is a naturally occurring soil-borne bacteria that causes serious illness and death in many cases of human infection. It can be passed from cows to people through wounds on the skin, by eating infected meat or breathing in spores, often from contaminated animal skins or during slaughter. Without treatment it is fatal in almost all cases but antibiotics – if given quickly – can save some people. Thankfully, it’s now a rare disease, with the greatest risks being among veterinarians, farmers, and those who handle animal wool, hair, hides, or bone meal products.


This is a bacterial disease that affects the reproductive systems of animals and causes recurring fevers and arthritis. People can become infected through direct contact or aerosol exposure, and it can also be transmitted through drinking untreated infected cows’ milk. Symptoms in people include flu-like signs, joint pain, and recurring fevers. In more severe cases, organs – including the liver, heart and central nervous system – may become inflamed. It can be fatal.

Bovine Spongiform Encephalopathy (BSE)

BSE is a progressive neurological disorder of cows which began – it is thought – when these herbivorous animals were fed meat products. In cows, the disease progresses slowly but eventually infected animals tremble and stumble, and become fearful or aggressive. It is fatal in 100% of cases. People who eat the meat of infected cows develop a variant called Creutzfeldt-Jakob disease. Initial symptoms include behavioral changes, lack of coordination and dementia, followed by coma and death, also in 100% of cases. There is no cure.


This diarrheal disease is caused by a microscopic parasite which can live in soil, water, and food contaminated by the feces of infected animals, including raw milk. It lives in the guts of infected people and animals (including cows) and is passed through their feces. Symptoms include watery diarrhea, cramps, nausea, vomiting, fever and weight loss, which can last up to four weeks. There is a higher incidence in children, and it can be serious in the immunocompromised. It is thought that climate breakdown could lead to a rise in infection rates in Europe.


A bacterial disease that affects multiple species, dermatophilosis is most common in young or immunocompromised animals or those exposed over a long period to wet conditions. For this reason, farmers call it ‘rain scald’. It begins with a moist circular patch often with matted hairs, and spreads rapidly. People who come into contact with it may develop pustules which will later break down to form ulcers that heal but leave scars.

Escherichia coli

This nasty foodborne pathogen causes bloody diarrhea, gastroenteritis and occasionally, life-threatening kidney failure. Ruminant animals on farms act as a natural reservoir and so it is not surprising that transmission typically occurs when people eat the undercooked flesh of cows and other animals (or any food contaminated by it) or drink deficiently pasteurized dairy products. Children and the elderly are more at risk from suffering severe poisoning, and more at risk of dying.


Giardia is one of several protozoan parasites that affect cows, and some strains can also infect people. Giardiasis is characterized by diarrhea, abdominal cramps, bloating, and weight loss. It is spread through feces. A study of 242 outbreaks found most were connected to water (drinking it and recreational contact) while eating infected food accounted for 16 percent. Giardia can be found within every region of the US and causes 1.2 million infections annually.


This bacterial disease is common in cows exploited for their meat and their milk, and causes them to suffer abortion, infertility and renal infection. The bacteria can transmit to people through direct or indirect contact with infected animals, especially through their urine (including foods contaminated with it, and swimming in waters where there has been runoff). Symptoms can be mild (flu-like aches and fever) to severe, including mental confusion, jaundice and damage to the liver, kidney and brain. It can be fatal.


Listeria bacteria are widespread in the environment and cows usually get infected through eating contaminated corn silage. From cows and other ruminants, it is spread to people through direct contact or inhalation, or through eating infected meat. In September 2019, a serious outbreak was traced to deli meats and cheeses. It infected 10 people from four states with one person from Michigan dying. The most severe effects occur in the elderly and the immunocompromised. Pregnant women rarely show symptoms themselves, but it can prove fatal to the fetus or the newborn baby.


This virus causes a painful infection in cows, causing papules on their teats and udders. It is common for entire herds to be infected. It passes to people through direct contact which makes farmers most susceptible, though veterinarians and slaughterhouse workers may also be affected. The virus causes red, raised spots on the fingers, hands and arms that within a week become tender. It is a mild disease and the symptoms normally disappear after a few weeks.

Q Fever

The ‘Q’ stands for ‘query’ because the cause of the first outbreak among Australian slaughterhouse workers was not known at the time. Today, we know it is an infectious bacterial disease that in ruminant animals can lead to abortion, stillbirth and fertility disorders. When transmitted to people – which happens via birth products, feces, urine and milk – it can cause no symptoms at all, or it can lead to high fever, headache, muscle pains, vomiting, chest and stomach pains, and pneumonia. It can also affect the liver. In some cases, a severe debilitating disease occurs, which is often fatal. Q Fever is so highly infectious that a single inhaled organism can cause sickness.


This is a severe viral disease that can affect all mammals including people. In cows, it attacks the nervous system, brain and spinal cord, causing brain deterioration and death. It is usually transmitted to people through being bitten by an infected animal but can also occur if saliva gets into a person’s nose, mouth or eyes, or into a wound. However, it is not just farm workers who are at risk. It can be passed from cows to people who drink infected unpasteurized milk. Symptoms include fever, headache, confusion and abnormal behavior. Death is almost certain.


Ringworm is a common skin disease caused by a fungus. It can affect many animal species, including cows in whom it causes lesions, commonly on the head and neck but potentially anywhere in the body. People become infected via direct contact with animals. The most common symptoms are itchiness and the appearance of a rash in a ring, from which the condition gets its name. It can be treated with topical fungal medication.


This is a very common bacterial infection which can cause severe diarrheal illness, especially in children, the elderly and the immunocompromised. The bacteria are shed in feces, which then contaminate foods, usually of animal origin, including ground beef. Transmission may also be via direct contact with infected animals. Salmonellosis causes about 1.35 million infections, 26,500 hospitalizations, and 420 deaths in the US every year.


Historically, tuberculosis came from cows, and it still can be passed from cows to people today through drinking unpasteurized milk, direct contact with an infected animal or by inhaling the bacteria coughed out by cows. It can then be passed person to person. There are two types of this bacterial infection, and the bovine type is responsible for 2 percent – around 230 cases – of TB in the US. In people, it can affect the lungs and lymph nodes, cause night sweats and weight loss. If untreated, it can be fatal.

Vesicular Stomatitis (VS)

A viral disease that affects cows and other animals, VS is endemic in the warmer regions of North, Central, and South America. In cows, it causes painful blister-like lesions to form in the mouth and nostrils, a reluctance to eat and weight loss, as well as fever, drooling, and lameness. It is passed to people through direct contact, biting insects and inhalation. It brings on an acute influenza-like illness with fever, muscle aches, headache, and malaise.


Many, though not all, these diseases are transmitted to people through close contact with cows, making farmworkers, slaughterers, butchers and tanners most likely to become infected. However, there are also serious risks from eating cows’ meat or drinking their milk. To reduce the risk of foodborne diseases, it is best to avoid handling and eating animal products altogether.

To fully protect the human population, however, we need to end animal farming. Causing severe physical and emotional stress to cows – as when they are forcibly impregnated to make them produce milk and their young taken from them to stop them drinking it – makes them more susceptible to disease. When we treat them this way, it is not just a cruelty to them, there are repercussions for people, too. Some bovine diseases are highly infectious, and can spread rapidly among the human population, whether or not individuals eat the meat. But none of this is inevitable. This damaging industry exists only because we buy the products. We can end the immense destruction that breeding so many cows causes – to forests, to wildlife, to the climate and to our health – by simply choosing to eat plant-based foods.


Farming, breeding, trading, transporting, slaughtering, butchering and eating cows or drinking their milk has had a huge impact on our health as well as our planet. As well as driving global deforestation, which brings about the decimation of wild animal populations, it is a significant driver of climate breakdown. The industry is also a leading polluter, emptying slurry into our waterways that poison the water and kill aquatic life. We are paying a heavy price for eating animals, and that is before we factor in the damage that farming and eating them does to our health.

Instead of treating the animals with whom we share this planet with respect – because after all they are here with us, not for us – we have behaved like a bully, locking them up, taking their young, and denying them everything that would make their lives worthwhile. Cows are inseminated and bred from repeatedly until they are no longer optimally fertile and after years of physical and psychological torment, they are trucked to slaughter.

We can be better than this. We can behave with compassion to the animals and world around us, and we can take care of our own health and that of the people we love. And we can do all this with one small step: eating plant-based.

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