SKIN CARE: DISEASES ACQUIRED FROM ANIMALS
A variety of animals—both domestic and otherwise—are known to transmit diseases to man. Several bacterial infections which affect humans may be contracted from animals. Domestic dogs and cats, being the most popular of household pets, are especially likely to be implicated in this regard. Both staphylococcal and streptococcal germs are carried in the mouths and throats of dogs and cats, and are easily transmitted to their owners. As well as transmitting their own infections to man, pets may also convey infections they themselves have acquired from man back to man himself.
Brucellosis is a bacterial infection of cattle, sheep, goats and pigs. This may he contracted by humans, either through contact with infectious milk or directly from the infected animals. In addition to skin infections, brucellosis may cause a high fever and muscle pain. Another bacterial disease, anthrax, is contracted from the handling of infected bones, hides, wool or hair of animals. The disease may cause severe pustular infections, associated with very high fever, and may be fatal. Cat-scratch disease, which usually results in painful, enlarged lymph glands and rashes, may be contracted as a result of being scratched by an infected cat or kitten. Tropical fish enthusiasts are not immune from infection either. The water in tropical fish tanks is often contaminated by the bacteria Mycobacterium marinum, which closely resembles the tuberculosis germ. It may also be present in lakes or heated swimming pools. Infection usually occurs at the site of an abrasion. It appears as a lump or infection, which breaks down to form a non-healing sore. Most commonly, ft occurs on the hands. Treatment with the appropriate antibiotic is most satisfactory.
Similarly, there are a number of viral infections of animals which may affect humans. These include ornithosis, a most unpleasant disease which may affect the lungs, heart or liver, and cause a fever and a fairly characteristic rash. Another viral infection, foot-and-mouth disease, is common in European and Asian farm animals. Rarely, however, does it infect man. When it does, it results in blisters of the mouth, tongue, lips and the palms and soles. It tends to be more severe in infants and children than adults. The disease milkers’ nodule is derived from the teats of infected cows, and results in tender, red lumps on the fingers of those who milk these cows. Orf is a similar condition, mainly derived from lambs. It infects humans, either through their direct contact with the affected animal, dead or alive, or even through contact with contaminated pastures. It results in painful nodules on the hands which may ulcerate.
Animals are also known to transmit a number of fungal infections to man. Four of these infections are frequently causes of ringworm; they are: microsporum canis, commonly found on cats and dogs; trichophyton verrucosum, commonly found on cattle; trichophyton men tagrophytes and microsporum gypseum, soil inhabitants. (Ringworm is discussed in detail on page 73.1 There are other fungal infections which not only infect the skin but the internal organs as well. Fortunately—for they are difficult to treat—such infections are rare. In Australia there are three forms which are known to affect man: sporotrichosis, blastomycosis and cryptococcosis.
Certain parasites harboured by our pets may be transmitted to us accidentally; these parasites may be a source of irritation in themselves, or they may be carriers of some disease. One of the more serious of these parasite-transmitted diseases is hydatids. Normally, the tapeworm responsible for the disease lives in the intestine of the dog and if its eggs are accidentally swallowed by man, large hydatid cysts develop internally. The common intermediate host is the sheep, which may eat infected grass. Other parasitic worms which may affect humans are cat or dog hookworms. These may be picked up from infested soil, the worms depositing larvae which are able to penetrate the skin. This results in a characteristic creeping eruption. Similarly, swimmers itch is caused by penetration of the skin by the larvae of bird worms. This is usually picked up in shallow lakes from snails, which are the intermediate hosts. Another infection, leptospirosis, is an infection caused by a parasite frequently found in domestic animals (including dogs, pigs and cattle) and rats. Humans are usually infected by contact with infected urine via a cut or an abrasion. The resultant illness may be experienced as a mixture of fever, muscle pain, rashes, headaches and jaundice.
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