Quite a number of contagious diseases originally found in animals can be transmitted to humans. This transmission occurs either directly by touching sick animals during treatment, maintenance, and care, or even during the processing of raw animal products (hides, hair, bristles, etc.) to which the pathogens adhere and through the consumption of animal products (meat, milk) that are contaminated with the pathogens.
Contagious and transmissible animal diseases.
Quite a number of contagious diseases originally found in animals can be transmitted to humans. The causative agents of animal diseases that can be transmitted to humans are bacteria or viruses. The most important of these animal diseases that can be transmitted to humans are: anthrax, rabies, Bang’s disease, psittacosis, tularemia, tuberculosis, listerosis and glanders. The systematic control of animal diseases on the basis of the provisions of the Animal Diseases Act, the Meat Inspection Act and the Dairy Act has succeeded in largely limiting the risk of their transmission to humans. On the other hand, the obligation to report cases of disease in humans, introduced by the Ordinance on the Protection of Communicable Diseases, has proved to be extremely valuable, not only because humans are protected from the spread of contagious diseases, but also because the discovery of these cases of disease leads to the detection and thus elimination of the sources of infection in the animal. Let us now look a little more closely at the individual diseases that can be transmitted from animals to humans:
Anthrax
Anthrax is subject to compulsory notification under the Livestock Diseases Act. From this alone it is clear that we are not dealing with a harmless disease. All three manifestations of anthrax, cutaneous anthrax, pulmonary anthrax and intestinal anthrax have ceased to occur in Germany, except for very isolated cases, because the main sources of infection, animal hides imported from South America and Africa, are hardly processed anymore.
Rabies
Rabies primarily affects dogs and cats and, more recently, frequently affects game (foxes and hares). The causative agent of rabies belongs to the viruses. After infection in humans and animals, the virus lives mainly in the brain and spinal cord. Infection occurs through the saliva containing the virus, which gets into wounds or minor injuries of the skin when bitten or licked or touched. The incubation period (which is the time between the bite and the onset of the disease) is 3-10 weeks in humans. The disease begins with headache, insomnia, painfulness, burning and itching of the old bite site and difficulty in swallowing. Therefore, in case of bites and scratches by the mentioned animals, one should immediately seek medical treatment. Every hour is precious. Special care should also be taken with foxes and hares, which, because they appear familiar and tame, are brought by children from the forest to play with. They often have rabies, and the so-called stage of silent rabies. Today, to protect against rabies in humans, protective vaccination is carried out when infection is suspected. Control of the disease among animals is regulated by the Law on epizootic diseases.
Bang’s disease and brucellosis
Bang’s disease (brucellosis) or abortus bovis band is the disease of epidemic calving in cattle. There is a possibility of infection for humans, especially through occupational handling of cattle and cows with the disease, which can excrete the pathogen with the prematurely expelled fruit, the amniotic fluid, and with the milk, possibly over a long period of time and in large quantities. The pathogens enter the human body through minute skin lesions via the mucous membranes and apparently also through uninjured skin. However, humans can also contract Bang’s disease if they consume raw milk containing bangbacteria. It sets in an average of one to two weeks after infection has occurred, with an attack of fever and more or less pronounced general complaints.
Parrot disease and ornithosis.
In the budgerigar, the cute little parrot bird, which is much kept as a pet and funny companion, one looked so far for the main carrier of the viral disease psittacosis, ornithosis or parrot disease.However, more recent research has shown that other bird species also transmit the virus, and today we are already talking more about ornithosis (bird disease). The symptoms of the disease are quite uncharacteristic in birds. Usually the disease can be diagnosed only after the bird is dead. Humans become infected by inhaling the virus-containing dust that the lively animals spread into the environment. Kissing and other similar foolish customs among such keepers, who forget that animals live in an animalistic and thus unhygienic way, may also have caused many an infection. We note an increased occurrence of psittacosis in winter, which is explained by the closer coexistence between humans and animals. Humans fall ill after an incubation period of 7 to 14 days with flu-like symptoms, and the temperature quickly rises to 40 degrees. If the course is favorable, the disease lasts 3-4 weeks with subsequent recovery lasting many weeks. In the diagnosis, the previous history, which indicates that the patient lived together with budgies or other birds, is important. Children and adolescents rarely become ill.
Tularaemia and rabbit plague
Tularemia, or rabbit plague, named for the place where the disease was first detected in humans in Tulare, California, occurs epidemically mainly in wild hares and rabbits, in which it is almost always fatal. The disease also affects humans, usually in an attenuated form. The pathogens can be transmitted both by direct contact with sick animals and their excretions or blood, and by blood-sucking insects. In humans, tularemia usually begins with a sudden onset of fever, headache, and back pain. At the site of entry of the pathogens, there is often the formation of a small poorly healing ulcer. From here, a painful swelling of the neighboring lymph nodes then develops, sometimes turning into suppuration. Diseases of the chest and abdominal organs may occur. After an average of 2-3 weeks, the febrile stage of the disease subsides. However, the general complaints mentioned above last longer and condition a long recovery period.
Tuberculosis
Domestic animals such as sheep and cattle can also transmit diseases. Tuberculosis (bovine tuberculosis) of cattle as a transmissible disease to humans should only be mentioned, but not discussed. Especially for the farm household and for the vacation guest in the countryside, there is an urgent warning not to drink uncooked milk. The responsible doctor and veterinarian warns with the words “bovine tuberculosis is infantile tuberculosis”. Milk processed in dairies does not contain tuberculosis germs.
Listeriosis
Slightly more prevalent than in the past, listeriosis is now found in humans and is transmitted by almost all domestic animals, but most commonly by sheep, cattle, rabbits, chickens, and pigs. The risk of infection from diseased animals is particularly high for small children and pregnant women. Rarely does the mother become ill, but listeriosis has often been found to cause stillbirths or premature births. The germs are excreted in the animals’ urine, milk, or, in the case of animal abortions, lochia. Infection of humans occurs by mouth or touch and causes a disease similar to meningitis. As with most infections, the most scrupulous cleanliness in humans and immediate treatment of sick animals is the best protection. More detailed explanations about glanders, one of the most dangerous diseases transmissible from animals, need not be given here, since it is as good as eradicated in Germany due to measures taken concerning epizootics.
