What is the cause of epidemic typhus?
summary
Body lice is the main vector of typhus. The epidemic of this disease is closely related to the growth and decline of human lice, so it is often prevalent in winter. It is easy to occur in cold areas in the north. It is easy to be prevalent in the period of war and famine and poor personal hygiene. Endemic typhus is mainly transmitted among rats. What is the cause of epidemic typhus? Next, I'd like to share my views with you.
What is the cause of epidemic typhus?
The pathogen of this disease is Rickettsia przewalskii, which parasitizes in the cytoplasm of human and animal vascular endothelial cells and the epithelial cells of human louse intestinal wall. During Rickettsia, it also adheres to red blood cells and platelets. Its basic form is rod-shaped, arranged in chains along the long axis. However, in the intestine of the lice, it has many forms, such as globular, short rod, rod or long line.
About 0.3-1 μ m × 0.3～0.4 μ m. Gram staining was negative. The chemical composition and metabolites of pathogens include protein, sugar, fat, phospholipid, DNA, RNA, various enzymes, vitamins and endotoxin like substances. The lipopolysaccharide layer of its cell wall has endotoxin like effect. Rickettsia przewalskii is very sensitive to heat, ultraviolet and common chemical disinfectants. It can be inactivated at 56 ℃ for 30 minutes. It has strong tolerance to low temperature and drying. It can survive for several months in dry lice feces.
Rickettsia typhi and Proteus ox19 antigen components have cross, so the patient's serum can agglutinate with Proteus ox19, namely waifei reaction. Rickettsia przewalskii contains both soluble and heat-resistant group specific antigens. The latter can be used to differentiate from Rickettsia Mori infection by serological examination.
matters needing attention
The management of patients with infectious source should be treated by killing the lice. After killing the lice, the isolation can be removed, but it is still suitable to concentrate in the special ward or this ward, bathe the patients, change clothes, wash the hair for many times, and spray insecticides such as 1% - 3% malathion into the clothes and hair.
