What are these ugly growths on my cow?

A cow suffering from warts. Warts are viral infections of the skin.

Growing up in my village as a boy, we were brought up to believe it was a taboo to come into contact with another person’s saliva for fear of contracting a skin infection. We referred to this disease as “Puch” in the local dialect. Many years later I would interact with this disease.

This time I would encounter it in the world of academia.

As I would learn, the kinds of warts that occur on human or animal skins are caused by Papilloma virus transmitted by direct or indirect contact. This virus is in the same family with Human Papilloma Virus (HPV) which causes genital warts – a sexually transmitted infection.

Photo of sick cow goes viral

I find this a disease of interest because recently, an image of an animal severely affected by bovine warts (Papilloma) was circulating on social media attracting loads of attention. Key board warriors as usual came up with all theories including claiming that the cow was bewitched. Dark chemistry aside, I will focus on the science.

The virus that causes warts in animals is known as bovine Papilloma virus. Just like in humans, bovine warts are spread by direct or indirect contact among cattle. Usually, the infection begins as a single wart and spreads to closer parts of the body eventually forming a forest of warts that can be scary.

Sometimes, the warts may develop wounds after which they become infected and produce bad odours or bleed continuously affecting the health of the animal. In some farms, Bovine papillomatosis has occurred as an outbreak where many animals are having warts in various parts of the body due to transmission within the herd. In severe cases, these warts can develop in the digestive system and the bladder causing cancer.

Self-treatment with vaccine

Like any other viral infection, there is no treatment for warts but animals suffering from it are easy to treat from their own warts. This kind of treatment involves making a local vaccine by washing the warts clean using antiseptics and cutting off the warts from the affected animals and using it to make the vaccine. Such vaccines are known as autogenous vaccines.  The wart material is then crushed and treated with formalin to kill the live papilloma viruses. This product is later filtered and an antibiotic added to prevent bacteria from growing in it. The product is then ready for use on the animals being injected between once to four times depending on how bad a case is. This product has to be prepared within laboratory settings by trained personnel who can safely handle the virus material and chemicals.

The vaccine can be produced with limited resources.

To prevent and control this disease, cull animals that develop warts before infecting others.

Other papilloma like infections

During a recent working trip in Nandi County, I encountered an outbreak of a disease that affected the teats of milking cattle causing them to develop blisters which formed wounds. Most farmers wondered if it was caused by their milking techniques. We were glad to explain that it is a condition known as bovine mammilitis caused by bovine herpes virus and is spread by contact and flies. Being viral, it has no specific cure but the wounds have to be treated with antibiotics to prevent bacterial infections. This disease can be controlled by use of teat dips which kill such viruses, proper milking hygiene and control of flies in the cow shed or milking parlour.

The infections are caused by viruses but the good news is; the viruses are animal specific and cannot infect people who come into contact with them though researchers say such potential exists. Because they are closely related to HPV, Bovine Papilloma virus is being used to study the carcinogenic potential of viruses in this family such as HPV. This means that meat from animals slightly affected by papillomatosis can be consumed while those with severe infections will be condemned for aesthetic reasons.

-The writer is a researcher at Kenya Agricultural and Livestock Research Organisation (KARLO)

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