Rickettsial disease
Introduction
Introduction to Rickettsia Rickettsiosis is a general term for a variety of acute infections caused by certain pathogenic microorganisms in the rickettsia. It is a worldwide or endemic epidemic with varying clinical manifestations. The media are mainly arthropods such as cockroaches, cockroaches, crickets, crickets, etc., and can also occur due to the catching and biting of livestock such as cats and dogs. Most rickettsial diseases can be clinically characterized as fever, headache and rash triad, mostly in spring and summer, often bites, recent camping or occupational exposure history. Some are also accompanied by nervous system, cardiovascular system and other symptoms of the parenchyma, and some cause rash, and cause damage to the nervous system, circulatory system and liver, lung, spleen, etc., different ricketts can cause different The disease. basic knowledge The proportion of illness: 0.005%-0.008% Susceptible people: no special people Mode of infection: arthropod bite spread, fecal-mouth spread Complications: epidemic typhus
Cause
Etiology of rickettsial disease
Cause:
The media are mainly arthropods such as cockroaches, crickets, crickets, crickets, etc., and can also occur due to the catching and biting of livestock such as cats and dogs. In recent years, with the advancement of Rickettsia molecular biology (16srRNA sequence, DNA-DNA hybridization, whole DNA or gene fragments, plasmids, etc.), the old rickettsia classification has not fully reflected in the Rickett The whole picture of all species is derived from the new classification of Rickettsia based on genetic material. The analysis of 16srRNA sequences shows that Rickettsia can be divided into two subgroups, including the rickettsia ( Rickettsia), Ehrlichia, Afibia, Cowdria and Bartonella; gamma subgroups include Coxiella and Wolbachia ), many new species have been discovered, such as Rickettsiajaponica, Ehrlichia Chaffeensis, Ehrlicha Sennetsu, Bartonellahenselae, etc. The name of Rochalimaea has been replaced by the Baton body, so the pathogen of the hottest heat should also be called the Bartonellaquintana.
Prevention
Rickettsia disease prevention
(1) The source of infection is mainly small mammals (rodents) and livestock, while humans are the sole or major source of infection for epidemic typhus and war.
(2) The transmission route Most of the media are arthropods such as cockroaches, cockroaches, cockroaches, cockroaches, etc., various rickettsias exist in the symbiotic form in arthropods, Rickettsia ricketts, tsutsugamushi ricketts Body, small spider rickettsia, etc. and can be passed through the egg, sputum, sputum, sputum, sputum and other feces contain pathogens, and excreted with the feces; in addition, rickettsia in sputum and sputum can still enter the salivary gland In the genital tract, various rickettsias mainly enter the human body through the bite of arthropods, and the benacox body enters the body mainly from the respiratory tract and causes infection.
(3) People who are susceptible are generally susceptible, and there are large differences in the number of people with different rickettsial diseases.
After human infection, it can obtain quite stable immunity. There are still cross-immunization phenomena in each group of rickettsial (old classification). After some patients recover from the disease, the pathogen can still stand in the body and move, and the immunity in the body is relatively weak. It can cause recurrence, but it usually occurs within 1 to 2 weeks after stopping the drug. It may be related to the application of chloramphenicol, tetracycline, etc., too short a course of treatment, and several months after the epidemic typhus. It is a special case that it can recur without reinfection for several years (called recurrent typhus).
Epidemic typhus, endemic typhus, Q fever, etc. are distributed worldwide, and many spotted fever groups with sputum as a medium are endemic, and more common rickettsial diseases in the country have epidemic rash. Typhoid fever, endemic typhus, tsutsugamushi disease, Q fever, rickettsial disease in North Asia.
Complication
Rickettsia complications Complications epidemic typhus
Some are also accompanied by nervous system, cardiovascular system and other symptoms of the parenchyma, and some cause rash, and cause damage to the nervous system, circulatory system and liver, lung, spleen, etc., different ricketts can cause different The disease.
Symptom
Rickettsia symptoms common symptoms triad fever accompanied by rash
Most rickettsial diseases can be clinically characterized as fever, headache and rash triad, mostly in spring and summer, often bites, recent camping or occupational exposure history.
Examine
Examination of rickettsial disease
Although there are many methods for the diagnosis of rickettsial disease, the most common ones are still the external Fiji test. It is advisable to take two or three serum samples (first admission, week 2 and recovery period) titration titer at 1 : 160 or more are positive, more than 4 times increase is more diagnostic, the second most commonly used for the complement test and micro-agglutination test, other such as IFA, ELISA, solid phase radioimmunoassay (SPRIA), latex agglutination test, Indirect hemagglutination test, immunoelectron microscopy, etc. are also helpful for diagnosis, but they are rarely used clinically or for research, epidemiological investigations, etc.
The isolation of pathogens can be carried out by chicken embryo culture, tissue culture, or guinea pigs, mice, rats and other animals. The pathogens of wartime fever can be grown on blood agar-based medium, except for war cell and other Barton. In addition, the primary isolation of other human rickettsial pathogens was inoculated with guinea pigs or (and) mice. Due to the small amount of rickettsia in the blood, vaccination and tissue culture methods often fail and lead to laboratory transmission. Not suitable for promotion.
Early effective treatment can delay antibody production by about 1 week, so serological tests must be repeated once every 4 to 6 weeks after onset.
Diagnosis
Diagnosis and differentiation of rickettsial disease
Four kinds of rickettsias that are closely related to humans.
1. Platts rickettsia, a pathogen of epidemic typhus and typhus, which is short rod-shaped, 0.8 micron to 2 micron x 0.3 micron to 0.6 micron, or up to 4 micron, single or It is short-chained. When a person is infected, after 10 to 14 days of incubation, sudden onset, severe headache, pain and high fever, rash after 4 days to 7 days, severe hemorrhagic rash, and some With symptoms of the nervous system, cardiovascular system and other parenchymal organs, epidemic typhus, in the densely populated and insect-rich environment is more serious, when the epidemic, the average patient mortality rate is 20%, in severe cases up to 70 %, pathogens are transmitted by people in the crowd, so mites are an important measure to prevent epidemic typhus.
2. Morse rickettsia, is the pathogen of endemic typhus (also known as rat typhus), its transmission is different from that of rickettsii, its natural host is house mouse, mainly by The groin spreads in the rat. If the mouse dies, the squid leaves the mouse and sucks the blood, causing the person to be infected.
3. Rickettsia rickettsia, the pathogen of the Rocky Mountain typhus, was first discovered in the valley of Montpellier in the Rocky Mountain region of the United States. When the disease is endemic, the patient mortality rate is as high as 90%. In the natural world, the rickettsiae is parasitic in the animals inhabited by cockroaches and cockroaches.
4. Ascariasis Rickettsia is the pathogen of scrub typhus (juni typhus). This disease was first discovered in Japan. At present, there are cases reported in the southeastern coastal areas of China and Taiwan Province. In Japan, the mortality rate of patients is about 60%, this pathogen invades the human body by bite, spreads with blood to the vascular endothelial cells, and the pathogens, the animals that store the pathogens are wild rodents and spread by ticks, get tsutsugamushi disease, first ulcers appear at the bite, around There is a blush, and the ulcer is covered with black eschar. In addition, there is a rash and causes damage to the nervous system, the circulatory system, and the liver, lungs, and spleen.
It can be seen that different rickettsia can cause different diseases, but because they have some common characteristics, the treatment methods also have some commonalities, such as general infusion, good care, isolation, etc., and the medications are similar, usually Under the treatment of rickettsial disease can use broad-spectrum antibiotics, has a higher efficacy, when using chloramphenicol to treat tsutsugamushi, it must be used continuously for 4 weeks, otherwise it is easy to relapse, tetracycline drugs are also effective, and can also be used for treatment Typhus and so on.
