1. BACTERIOSES
1.1. SALMONELLOSES
Salmonelloses is a group of human diseases caused by more than 2,500 serovars of Salmonella type bacteria, represented by two species - S. Enterica and S. Bong-ori of the Enterobacteriaceae family. These include typhoid fever, paratyphoid A, paratyphoid B and salmonellosis, focal purulent infection.
1.1.1. Typhoid Fever
Typhoid fever is an acute anthroponosis with fecal-oral mechanism of pathogen transmission. The disease is characterized by bacteremia, damaged intestinal lymphatic system, cyclic course, fever, intoxication, maculopapular rash, and hepato-splenomegaly.
History. In 1820 Pierre Bretonneau described typhoid fever as an independent disease. In 1829 Pierre Louis described the clinical signs of the disease and anatomical changes in the intestine and named the disease «Typhus abdominalis» (typhoid fever). The causative agent was discovered in 1880 by Karl Joseph Eberth and was isolated as a pure culture in 1884 by Georg Gaffky. A great contribution to the study of the disease was made by S.P. Botkin, N.K. Rosenberg, G.F. Vogralik, A.F. Bilibin, K.V. Bunin and other Russian scientists.
Prevalence. Typhoid fever is recorded worldwide as sporadic cases, local outbreaks and epidemics. It is more common in countries with low sanitary culture, high population density, lack of centralized water supply and sewer system. In Russia, the highest incidence is registered in the North Caucasus and the Volga region.
Etiology. The causative agent - salmonella (S. Typhi, serogroup D) is a small Gram-negative rod-shaped bacteria that is mobile due to the presence of a large number of flagella. It grows well in culture media that contain bile. The optimum growth condition is 35-37 °С. Resistant in the environment. It is able to survive for 1 month in fresh water, on vegetables and fruits - up to 10 days, it can grow in milk and dairy products. The most important antigens are flagellate antigen - H-antigen, somatic - O-antigen and Vi-antigen (virulence antigen). Typhoid bacillus is lyzed by specific phagocytes (more than 100 phagotypes); it can build L-forms. It contains endotoxin (LPS).