In a previous post, we discussed a skin condition called Mange, that is especially common in small pet and domestic animals and caused by mites. Now, we will discuss another skin condition that is also zoonotic, common in livestock animals (especially large animals), but caused by an entirely different organism – Dermatophilosis
Dermatophilosis is also known by our local livestock farmers here in our country as Kirchi. Scientifically, it is can be referred to as cutaenous streptothricosis and in other parts of the world it is called strawberry footrot or rain scald. When it occurs in sheep, it is commonly called lumpy wool.
Dermatophilosis rarely causes significant disease or death of the animal. However, in widespread and extreme cases, it gives the animal an un-cosmetic rough and somewhat ugly appearance. Also, in this part of the world where the skin of our livestock animals is consumed as a delicacy (ponmo), a cattle with dermatophilosis will not be able to produce ponmo for consumption. This will cause economic and financial losses for the farmer or livestock producer.
Dermatophilosis is a skin disease caused by a bacterium called Dermatophilus congolensis (derm-ah-TOFill-us con-go-LEN-sis). It can affect many species of domestic and wild animals such as cattle, sheep, goats, horses, and less frequently pigs, dogs, and cats. It can also sometimes affects humans making it a zoonotic disease.
How is dermatophilosis is transmitted to animals?
The bacterium that causes dermatophilosis is found on the skin of diseased animals and also animals that show no signs (carrier animals). The disease is spread by direct contact between animals or through exposure to environment containing the bacteria or by biting vector insects, particularly flies and ticks. There are high-risk factors that promote the establishment of the disease and allow the bacteria to spread in the animal and these include prolonged wetting of the skin by rain, high humidity, and high temperature. Therefore in Nigeria, the disease can be most commonly observed during rainy seasons and in persistently murky wet livestock docks, pens and farms. This moist/wet skin and environment allows the penetration of the bacterium and establishment of infection in the animal. Also, dermatophilosis can occur in animals of all ages but is more common in the young.
How is dermatophilosis spread to humans?
The skin disease can be transmitted to humans by direct contact with an infected animal. Typically, infection leads to the development of non-painful pustules on the hands and arms. These sores will later break down to form shallow red ulcers that heal and leave scars.
Signs and symptoms of dermatophilosis in your livestock animal
Initially there is a matting of hair that has a paintbrush appearance. This leads to scab or crust formation that may have pus underneath and may cause itching in some animals. Dermatophilosis can be seen along the dorsum where it causes serum exudation and scab formation at the base of the hairs. In some cases, the disease is associated with loss of body condition and decreased milk production, however, the lesions rarely develop clinical significance.
The affected areas of cattle are often distributed over the head and the top of the neck and body. Sores caused by biting flies are typically found on the back while those caused by ticks are primarily on the head, ears, under the legs, and in the groin area. Animals can develop the condition on the lower legs from standing for long in water or wet pens. Also, in the presence of large numbers of ticks, affected animals can develop sores all over the body that may lead to death as their condition deteriorates.
Affected animals should be taken to the veterinary doctor. They will be given antibiotics, anti-inflammatory and topical treatment/disinfection to reduce the bacterial load, resolve the damaged skin and promote healing. The best treatment and prevention would be to keep their skins dry, meaning that animals should be kept indoors, especially during rainy season. There is no vaccine for dermatophilosis.
Humans affected with dermatophilosis should contact a doctor for the appropriate treatment.
Control and Prevention of dermatophilosis in animals and humans
In case of a dermatophilosis infection in a herd of cattle or other domestic animals, the best method to control infection is to isolate infected animals and cull those that are chronically ill. Also, it is very important that external parasites such as flies and ticks be controlled or eliminated using insecticides/acaricides as they contribute largely to spread and persistence of infection.
In humans, dermatophilosis can be prevented by wearing gloves and protective clothing when working with an infected animal and washing thoroughly afterwards with anti-bacterial soaps. It is best for anyone with a weak immune system to stay away from an animal known to be infected with dermatophilosis.