Tsutsugamushi

Tsutsugamushi (synonym: akamushi, kudani fever, Japanese river fever) is an acute febrile illness caused by Rickettsia, proceeding with the presence of skin primary affect and rash.
The causative agent of tsutsugamushi - Rickettsia tsutsugamushi. The Keeper of infection in nature are rodents and some species of tick-tick (Trombididae). Infection occurs when a person tick sucked in larval stage living in the Bush, river valleys. In endemic of tsutsugamushi areas of occurrence of epidemics. The disease is widespread in South-East Asia, the Pacific Islands, Australia. In the Soviet Union documented cases in the Primorsky region and Tajikistan. Immunity after the disease of short duration.
The clinical picture. The incubation period - 5-21 day. Prodromal period may not always work. The disease begins abruptly, usually with a temperature rise to 38-39 degrees. Fever lasts 2-3 weeks. Bites of ticks (on his hands, armpits) notes primary affect as the sores, accompanied regional lymphadenitis. By the end of the first week of the skin appears maculata (spotted), then maculo-papular (spotted-knot) rash, threatened with falling temperature. Often, after a rash remains pigmentation. Fever is accompanied by headache, weakness, tachycardia, drop in blood pressure (severe cases of possible collapse). Some patients develop atypical flowing pneumonia, sometimes secondary hepatitis and jade. Recover slowly. The prognosis depends on the severity of the disease.
The diagnosis can be made on the basis of epidemiological data (stay in endemic area) and clinical symptoms: fever, primary affect local lymphadenitis. Laboratory diagnosis is crucial and is based on the allocation of the blood of the pathogen. From the second week of illness put an agglutination reaction with Proteus UCC, which is considered positive titers ranging from 1 : 80 and above.
Treatment of tsutsugamushi spend chloramphenicol, biomitsin, terramycin. Chloramphenicol administered in the dose of up to 5 g within 24 hours. With the aim of preventing recurrence after 8 to 14 days appoint 3-4
Prevention of tsutsugamushi comes to clearing and cultural development habitats krasnoselkoup ticks, the destruction of rodents, wear impermeable for ticks service, impregnated frightening off means. Recently proposed (N. He Kakcheev) live chemiakina.

Tsutsugamushi (synonym: Japanese river fever, scrub typhus, akamushi and others) - acute rickettsioses disease proceeding normally, with the presence of primary affect and makulo-papular rash.
Tsutsugamushi distributed only in the Eastern hemisphere. Significant outbreaks were observed among the colonial Anglo-American forces during the second world war.
The causative agent of tsutsugamushi - Rickettsia tsutsugamushi - first isolated Hayashi (N. Hayashi) in 1920 from the patient's blood in Japan, but mistakenly attributed to the genus Theileria. Nahayo (M Nagayo, 1930) and Ogata (N. Ogata, 1931) almost simultaneously identified and described the pathogen as R. and R. tsutsugamushi orientalis. In the world literature are used both terms.
The causative agent of tsutsugamushi on morphology differs from ricketsi group of typhus and from ricketsi group spotted fever. This is diplococci or diplomaticly, thicker and shorter than other Rickettsia, length from 0.8 to 2 microns and a width of 0.3 to 0.5 MK. R. tsutsugamushi, as rickettsiae group of typhus, breed in the cytoplasm of cells, never hitting nuclei. They are located in the cell loose groups or alone, are painted Romanovsky - Giemsa and Muromcevo in dark-purple, turning purple, Macchiavello and Skadovska painted in dark blue color, as they have a discoloration of fuchsin in differentiating acid, and in this case there has been a sharp polar staining.
Marked ability R. tsutsugamushi to lysis and fast their destruction in a room temperature. Vacuum drying is sharply reduced infectious titre rickettsioses culture. Long-term preservation of rickets is observed at temperature-20 to 70 degrees.
Like other intracellular parasites, R. tsutsugamushi not grow on bacterial environments. They are usually poorly breed in the yolk bags of chicken embryos; able to multiply in the body of white mice, rabbits, white and cotton rats, hamsters, Guinea pigs and monkeys. Most clearly and regularly infection is played on white mice. They develop generalized infection, ending with the death of 90-100% of the animals in 10-20 days (average 14) after infection. However, described the strains that cause latent chronic form of tsutsugamushi installed only in experiments immunity with repeated infection animals recover highly virulent strains.
Immunological properties R. tsutsugamushi studied enough. When tsutsugamushi not observed immunological cross-reaction with other pathogens ricketsiosis. I had been ill people and animals observed short immunity to re-infection. Antigenic structure R. tsutsugamushi original: significant antigenic variability of the properties of different strains. Japanese researchers have identified three serotypes R. tsutsugamushi, corresponding to the strains Gilliam, Karp and Kato. Serological kinship with other Rickettsia not described.
Tsutsugamushi can serve as a classic example of diseases with natural focality. The source of infection are the larvae krasnoselkoup mites (FAM. Trombiculidae)in which the pathogen is transmitted transfusio and transovarial. The most studied the role of the tick Leptotrombidium akamushi (akamushi).
Proximately larval mite - small rodents, marsupials, insect-eating - are in the process of circulation R. tsutsugamushi in natural foci and are an additional reservoir of infection.
Epidemiology of tsutsugamushi studied in detail in endemic foci of Japan and during mass outbreaks in New Guinea, Ceylon, the Philippine Islands, etc. are Usually among the local population are observed sporadic illnesses or outbreaks, dedicated to the field work, collection of dead wood, cane, etc. Infection of people tsutsugamushi occurs in habitats of larval mite (vectors), in river valleys, Japan and Australia, in thickets of coconut trees with abundant undergrowth and grass on the Pacific Islands, i.e. in places with warm, humid climate, favourable for ticks. The incidence among non-immune groups is an epidemic.

tsutsugamushi
Temperature curve of the patient severe form of tsutsugamushi (Blake).


The clinical picture of the disease in humans ranges from severe cases ending lethal, to the lungs, erased forms. After the incubation period 5-17 days [Philip (C. R. Philip) and others] or 10-18 days [Blake (F. G. Blake) and other] States sudden rise in temperature to 38-39 degrees; fever (Fig) lasts 10-21 days (Philip and others) or 1-2 weeks (Blake and others). In place of suction of the tick vector often produced primary affect. As a rule, are marked regional lymphadenitis and lymphangitis. By the end of the first or early second week on the body appears maculata rashes, passing then maculo-papular, it is sometimes on the soles and palms. Half of the patients after the disappearance of the rash is a long-term holding pigmentation. Febrile period accompanied by headache, General weakness, sometimes rapid pulse. Some patients develop secondary pneumonia, there comes a disorder of blood circulation and the Central nervous system.
After the political temperature drop within 1-3 days is slow recovery. In other cases, on the 2nd week of the disease is marked by death in the result of bacterial pneumonia, disorders of blood circulation and other phenomena. In recent years, described mild forms of tsutsugamushi occurring without rash, without a primary passion, with only intermittent fever and headache. Possible relapse.
Mortality in tsutsugamushi varies widely. In Japan before the use of antibiotics, the mortality was among people aged 11 to 20 years 15%, from 21 to 30 years up to 20% and over 60 years of 59% .
Clinical diagnosis difficult. Laboratory diagnostics
is made by the selection of strains from patients on white mice, and using a RAC.
Treatment of tsutsugamushi antibiotics (Chloromycetin, aureomycin and others) effectively. The prescription of antibiotics reduces febrile period and in almost all cases, warns death. Chlormycetin appointed dose of up to 5 g in 24 hours with extra reception 3-4 g in 8-14 days to prevent a recurrence.
Prevention of tsutsugamushi comes to protection measures include destruction of vegetation, drainage, agriculture, destruction of rodents - proximately mites, insecticide treatments in breeding sites mites. In the individual protection against ticks apply repellents and impervious to mites clothes. Specific prevention of tsutsugamushi not sufficiently developed. Killed vaccines are ineffective.
Cm. also Ricketsiosis.