The focus of the diseases cause the genus , which are transmitted by rodents and birds. These represent a natural for, causing recurrent disease patterns in animals and humans. In veterinary medicine, pseudotuberculosis is of importance. It is spread by free-living rodents, especially rabbits and hares. Many bird species also harbor the pathogens , so they can be transmitted to farm animals, such as , , , sheep and goats. Occasionally, domestic animals, z. B. Canary and , dogs, cats, chinchillas, and pygmy rabbits become infected. The Y. pestis, which ravaged Europe in the Middle Ages and led millions of people to their deaths.
with Y. Enterocolitica are more likely to be of concern to humans. The bacterium is occasionally found in foods, such as meat from home slaughter, raw milk, and raw milk products, e.g. B. goat cheese, and can lead to serious infections and clinical pictures, especially in small children.
The genus Yersinia contains numerous bacteria, of which three groups are most important: Y. enterocolitica, Y. pseudotuberculosis, and Y. pestis; the last two are closely related. There are a large number of different strains with a wide variety of antigenic structures, of which only a few are human pathogenic (causing disease in humans). They are pleomorphic (multiform) bacteria with an elongated shape. The bipolar staining (s. Fig.) is irregular and of no diagnostic significance.
Due to standard cultivation on culture media for intestinal bacteria, isolation is difficult. It is better to detect the germ on a special selective culture medium according to Schiemann. The germ shows characteristic growth on this culture medium. Accompanying flora is suppressed by special components in the agar. Biochemical procedures to classify the germ must then follow to determine whether it is Y. enterocolitica, Y. pseudotuberculosis or Y. pestis acts. Furthermore, in isolates from animals, the antigenic structure of the important. Conclusions can be drawn about the human pathogenic properties of the germ.
Y. enterocolitica and Y. pseudotuberculosis are widespread worldwide, Y. pestis, on the other hand, occurs only in certain regions (s. world map). The main sources of transmission are rodents, from which the pathogens are introduced into livestock buildings. Occasionally, birds may also be responsible for the spread. Pigs and goats are considered as pathogen reservoirs. The most common source of infection is contaminated food that has been poorly stored and contaminated by direct contact with infected rodents, such as mice and rats.
Plague is considered more of a forgotten bacterial infectious disease that has declined significantly since the 1950s. Nevertheless, new outbreaks occur again and again. The last reported plague outbreak occurred in New Mexico on 27.07.2005 on. The areas marked in red on the map are those where the plague still occurs.
Rats and fleas are primarily responsible for the spread, but dogs and cats can also support the pathogen spread. In the state of Colorado, a person is said to have contracted the pathogen while hunting rabbits.
This disease is more common in cats (through contact with rodents) than in dogs. Nevertheless, the disease is widespread. The symptoms are fever, vomiting, diarrhea or constipation. These are accompanied by swelling of the spleen and liver with jaundice, inflammation of the kidneys and bronchopneumonia ( of the bronchi and lungs). In chronic courses, joint inflammation may also occur.
This affects rodents such as rabbits, guinea pigs and chinchillas. Two forms of the disease are known. 1.- The form: There is blood poisoning with coughing, respiratory distress and death within 12-24 hours. 2.- The form with swelling of the lymph nodes, loss of appetite, emaciation, diarrhea (moderate to mild), rupture of the lymph nodes and release of germs with the pus. This is highly infectious for other animals and humans. In guinea pigs: Death after 3-4 weeks, other rodents can survive much longer.
Yersinia enterocolitica- or Yersinia enteritis ( ):
In dogs and cats, it is a facultative pathogenic enterobacterium, d.h. it does not necessarily, but possibly trigger one, especially when diarrheal diseases caused by Yersinia were detected in persons living in the household. A small number of Yersinia are present in 0-18% of stool samples. The germ count per gram of feces is crucial. Thus, germs can be introduced from clinically healthy permanent excretors, especially into chinchilla populations. Symptoms include acute or chronic diarrhea with mucous to bloody excretion, especially in young animals. The germs can penetrate into the lymph nodes and enlarge them greatly. Fever, vomiting and abdominal cramps may occur in some cases. If the disease persists, it can lead to emaciation and even death (frequently affected: chinchillas).
Plague: From 13. to 19. In the 19th century, epidemics occurred again and again at cyclical intervals.
The Plague of Azoth; painting by Nicolas Poussin, 1594-1665. The artwork shows Philistines suffering from the plague .
In the Middle Ages of the 14. Probably the largest epidemic of the plague in Europe took place in the middle of the sixteenth century (1347-1353), which depopulated whole areas of land. Via the trade routes from Eastern Europe, the Norway rat was introduced into the. Whose fleas introduced the disease. The term "Black Death was coined for the plague during this period. Bloodshot skin sections and bumps and necrotizing body parts that turned black with the formation of gangrene (s. Fig.) and died off, led to this obvious name, especially since in that time no antibiotic was possible.
Plague occurs in humans in four forms of disease
1. Bubonic plague is characterized by initially mild tumor-like swellings at the flea injection sites along the lymphatics and subsequently the lymph nodes. Fever, headache, and pain in the limbs occur first, followed by severe symptoms, such as drowsiness and unconsciousness. After an incubation period of six hours to a week, very painful bumps develop, which turn blue-black due to bleeding as the disease progresses. The bumps may eventually rupture and secrete a purulent, foul-smelling fluid containing large numbers of Yersinia (see painting). If the bumps break open inward, the septicemic form of the plague occurs. The pathogens are transmitted by the saliva of the rat flea. Disease outbreaks during summer are much stronger than in winter. The rat fleas actually prefer the rat. However, if there are not enough rats, so that food for the flea becomes scarce, a new host, z. B. the human being, visited. Contaminated food and water can also be a source of infection for the plague during an epidemic. 2. The septicemic form of the plague is a complication of the bubonic plague by internally broken bumps or wounds. These come into contact with secretions from the bumps, so that a blood poisoning with the germ takes place, which spreads over the whole body, leads to organ hemorrhages and causes death within 36 hours. 3. Pneumonic plague is also a complication of bubonic plague. The lung tie is affected and the germ can easily be transmitted from person to person by droplet infection. The death rate of this form of plague is very high: 94-98%. 4. The abortive form of plague is a mild, chronic form with mild fever and swelling of the lymph glands. It can cause miscarriages in women and infertility in men. The plague can also affect pets. Predominantly cats and dogs are sources of infection for humans. Wild rabbits and hares can also lead to human infection in rare cases.
The diagnosis can be made by bacteriological methods. In many cases, however, yersiniosis is only detected post-mortem by the pathologist.
Therapy can be by antibiotic treatment, provided that the disease comes to treatment at an early stage. In many cases, however, treatment is also not advisable, as the persistent carriers should be eliminated for the safety of humans and animals.
Above all, hygienic measures are of great importance, such as rodent control and shielding against wild birds. Food should be absolutely protected from contamination by rodents. A vaccination is available for humans against Yersinia pestis. Y. enterocolitica available abroad. enterocolitica available abroad. No vaccine against yersiniosis is approved for animals in Germany.