eperythrozoonosis
Introduction
Introduction to Eperythrozoonosis Eperythrozoonosis is a zoonotic disease caused by Eperythrozoon (referred to as red body), although the infection rate of Erythroid in the livestock population is quite high, but there are clinical symptoms and signs. Rarely, the clinical manifestations of this disease are mainly fever, anemia, diarrhea and lymphadenopathy. As early as 1928, Schilling et al. discovered red bodies from rodents, and until 1986, Puntaric et al. officially described human red body disease. In 1980, the first red-body was found in rabbits in China. The pathogens were found in livestock such as cattle, sheep, pigs, etc., and the presence of red body disease was confirmed in the population. basic knowledge Sickness ratio: 0.0001% Susceptible people: no special people Mode of infection: contagious Complications: jaundice
Cause
Eperythrozoonosis etiology
(1) Causes of the disease
Eperythrozoon, also known as the blood worm body, referred to as the red body, is a group of microorganisms parasitic on human, red blood cell surface, plasma and bone marrow. It is observed in general smear specimens, and its morphology is polymorphic, such as Spherical, circular, disc-shaped, dumbbell-shaped, racquet-shaped and comma-shaped (Figure 1), large fluctuations in size, parasitic in humans, cattle, sheep and rodents, the red body is small, diameter is about 0.3-0.8 Mm, and the red body in the pig body is larger, the diameter is 0.8-1.5m, and the maximum is 2.5m. The red body has both the characteristics of the protozoa and the characteristics of the rickettsia, and its classification status for a long time. It is uncertain that until 1997, Neimark et al. used DNA sequencing, PCR amplification and 16 SrRNA sequence analysis to be considered to belong to the genus Mycoplasma of the genus Membrane. Up to now, 14 species of genus Red genus have been found, of which five are mainly Species: 1 globular red body (E. coccoides): parasitic in rodents such as rodents and rabbits; 2 sheep red body (E.ovis): parasitic in sheep, goats and deer; 3 pigs attached E. suis: parasitic on pigs; 4 E.wenyonii: parasitic ; 5 short red body (E.parvum): is a non-pathogenic parasite of the domestic pigs, the resistance of the red body is not strong, stop exercising after 1 min in a 60 ° C water bath, all inactivated in 100 ° C water bath for 1 min It is generally sensitive to commonly used disinfecting drugs and quickly kills them, but can survive for several years under low temperature freezing conditions.
(two) pathogenesis
When the red body enters the human body, it is in a latent state in most cases. Only in some cases, such as decreased immunity or some stress state, the disease process is manifested. This indicates that the red body has low virulence and pathogenicity. Not strong.
Observation by electron microscopy showed that the red body mainly parasitized on the surface of mature red blood cells, did not enter the cells, and a small amount was released in the plasma. The parasitic mechanism was still unclear, but it was found that there were fibrils on the large red body, and the fibrils and red blood cells were used. Upon contact, binding, and then embedding on the erythrocyte membrane, there may be receptors bound to the fibrils on the erythrocyte membrane (Fig. 2). From the electron microscope, the surface of the red blood cells of the parasitic red body appears wrinkles, protrusions, and individual It can be seen that a hole is formed on the surface of the membrane. Due to the change of the erythrocyte membrane, the depression and the hole on the membrane cause the plasma component to enter the red blood cell, causing the red blood cell to swell, rupture, hemolysis, and the parasitized red blood cells are observed from the living specimen, and the plasticity thereof is The deformable function disappears and is easily destroyed and hemolyzed when passing through the mononuclear phagocytic system. The two main mechanisms indicate that there is both intravascular hemolysis and extravascular hemolysis in the hemolytic anemia of this disease, and hemolysis may be considered. Alteration of erythrocyte membrane structure, or exposure to a cryptic antigen, etc., induces the production of IgM autoantibodies, a type II allergy.
There is currently no human pathology data.
Prevention
Eperythrozoonosis prevention
At present, the epidemic of the disease is still unclear, so there is no good prevention.
Complication
Eperythrozoonosis complications Complications
In severe cases, jaundice can occur.
Symptom
Symptoms of Eperythrozoonosis Common symptoms Lymph node enlargement Astragalus joint pain and weakness
The infection rate of the red body in the livestock area is quite high, but all of them are subclinical infections. The clinical signs and symptoms can be diagnosed as red blood cells are more common in severe infections (more than 60% of red blood cells are parasitized), often occur in There are chronic basic diseases and immunocompromised patients, the main clinical manifestations are as follows.
1. Fever: The body temperature is generally 37.5 ~ 40 ° C, accompanied by excessive sweating, joint pain and so on.
2. Anemia: Anemia is the most common manifestation of this disease. In severe cases, there may be sclera and yellow skin staining, and there are symptoms such as general malaise, lethargy and mental euphemism.
3. Lymph node enlargement: Some patients have superficial lymph nodes, which are common in the neck.
4. Others: There are skin itching, hepatosplenomegaly, diarrhea (more common in children), hair loss and so on.
Examine
Examination of erythropoiesis
1. Blood picture: Low hemoglobin, reticulocyte is higher than normal, erythrocyte fragility test and syrup test are positive, white blood cells are generally normal, but abnormal lymphocytes appear.
2. Microbiological examination: It is the main basis for the diagnosis of this disease.
(1) Fresh blood pressure film method: Take 1 drop of fresh blood sample to be tested, drop it on the slide glass, add 1 drop of normal saline or anticoagulant, mix it, add cover slip, check with ordinary microscope After finding the red body in the 400-600 times microscope, observe the shape and size. It can be seen that the red body has a flash-shaped body, rotates or rolls in the plasma, and stops moving whenever it approaches the red blood cells.
(2) Smear staining examination: Take 1 drop of blood on the slide, make a thin blood film, fix it with Giemsa or Wright's stain, add cover glass with 400~600 times microscopic examination, Giemsa liquid will The red body is dyed into purple-brown, and the Wright's solution dyes it into purple-red color. After finding the red body, it is transferred to the oil lens (about 1600 times) to observe its shape, arrangement and size, and can be counted. A red blood cell surface can be attached. l ~ 67 with red body, can be found in the plasma and red blood cell surface, the ratio of the two is about 1:1 ~ 1:2.
Red body infection degree: 30 out of 100 red blood cells are classified as mild infection by parasites; 30 to 60 red blood cells are classified as moderate infection by parasites; more than 60 red blood cells are classified as severe by parasites infection.
3. Blood biochemical examination: The total bilirubin is increased, mainly indirect bilirubin, blood sugar and blood magnesium are low, and liver function is abnormal.
Liver and spleen were abnormally examined by ultrasound.
Diagnosis
Diagnosis and diagnosis of erythrocyte disease
In the animal husbandry area, there is fever, jaundice, anemia, itchy skin, hair loss and lymphadenopathy that cannot be explained by the primary disease. It is necessary to consider the possibility of combining the disease, timely blood smear examination, and find the red body for diagnosis.
The disease should be differentiated from malaria, Barton's disease.
Through microbial blood test, the genus genus and the malaria parasite are generally easier to distinguish, while the genus genus and the genus genus are difficult to distinguish, only by the morphology of the two blood samples and in the plasma and red blood cells. The proportion is identified, the former is often ring-shaped, and is distributed on plasma and red blood cells; the latter is rare in the ring, parasitic in plasma, rarely on red blood cells.
