Dysentery. Shigellosis.. Etiology

Dysentery. Shigellosis.

Dysentery is an infectious disease, accompanied by lesions of mucous membrane in the large bowel, especially in its distal part.

From the data of WHO, there are mannually registered up to the 275 million acute intestinal infections (AII) in the world. AII take the second place of morbidity after ARVI. In our country the level of mortality rate from AII amidst of mortality rate from infectious diseases is more than 30-50 %.

Dysentery belongs to one of the most widespread forms of AII. The clinical picture of the dysentery depends on the species of shigellae. Dysentery of Grigoriev-Shiga has the most severe course with acute colitic syndrome and neurotoxicosis. Shigella sonnei and Shigella flexneri cause 90% of the cases of shigellosis. Shigella flexneri cause a greater percent of heavy forms of disease than Shigella sonnei. Shigella flexneri cause more often toxicosis with dehydration, especially at children of early age, Shigella sonnei – neurotoxicosis.

Only early diagnostics of the first cases of illnesses in the hearth of dysentery can provide temporarily ly effective therapy and performing the complex of disease measures.

Etiology

Pathogens of dysentery belong to the genus of Shigella. All pathogens of this group are Gram-negative, they have no capsules and flagella and grow well on simple nutrient media not differing from each other morphologically. Only the pathogen of species of Grigoriev-Shiga Sh. dysenteriae produces an exotoxin, other pathogens produce endotoxins. Dysentery pathogens of various species have different stability in the environment. Sh. dysenteriae have the least stability. They retain their viability in water and milk for 3 days. Sh. Sonnei are the most stable. They retain their viability in water for 3 months, in milk for 10 days, in butter for 6–8 months. These peculiarities condition the spreading of dysentery among people. Dysentery brought about by Sh. Sonnei is most spread these last years while Sh. Flexneri takes the second place.

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