Rift Valley Fever
Introduction
Introduction to Rift Valley Heat Riftvalleyfever is an acute viral infection caused by Rift Valley fever virus that is transmitted by mosquito vectors or contacts. Clinically characterized by fever, headache, myalgia, exhaustion, photophobia, and leukopenia. basic knowledge The proportion of diseases: the incidence rate of forest workers is about 0.01%-0.05% Susceptible people: no special people Mode of infection: contact spread Complications: Hemorrhagic shock Hepatitis Retinopathy
Cause
Rift Valley fever
(1) Causes of the disease
Rift Valley fever virus belongs to the genus Bacillus virus of the Bunia virus family. It is a spherical type with a diameter of 80-100 nm, a long-fiber polypeptide envelope of about 5-10 nm long, and three helical nucleus, including a single The strand RNA genome consists of three subunits: L, M and S. Most viruses have three major virion polypeptides. The virus replicates in the infected cytoplasm and is sensitive to lipid solvents such as diethyl ether, deoxycholate and heat. It can be stored for several months at 4 °C, long-term survival at -20 °C, and the virus in the serum can be reactivated after 3 hours at 56 °C.
(two) pathogenesis
The pathogenesis of colitis has not been known so far, presumably due to the direct invasion of the liver and endothelial cells by the virus and the involvement of immune factors.
Pathological changes are extensive bleeding of the skin, subcutaneous tissue and internal organs.
Prevention
Rift Valley Prevention
In the epidemic area of this disease, mosquito and mosquito killing are extremely important preventive measures. Live attenuated vaccines have been used in humans and animals in South Africa. In recent years, formaldehyde inactivated vaccines have been used in veterinarians and other people at risk. Can be immunized for more than 2 years.
Complication
Rift heat complications Complications Hemorrhagic shock Hepatitis retinopathy
And hemorrhagic shock, intracranial hemorrhage, some patients may be complicated by hepatitis, encephalitis, retinopathy.
Symptom
Rift Valley fever symptoms Common symptoms High heat photophobia skin mucosal bleeding slow pulse pain retinal detachment
The incubation period is 3 to 6 days, and the high heat (38 ~ 40 ° C) can be double-peak heat, the heat course can reach 1 week, and there is photophobia, severe headache, muscle pain and relatively slow pulse, often no rash, occasional skin mucosa Small hemorrhage, rare hemorrhage, recovery is smooth, white blood cell count is reduced, complications can be central, serous retinitis and central dark spots, a few can cause retinal detachment, rare encephalitis (more often occurs 3 to 12 days after fever).
Examine
Rift heat check
Leukocytes increased slightly or normal within 1 to 2 days after onset, followed by a significant decrease in white blood cells, which may be less than 2×109/L, thrombocytopenia, and prolonged bleeding time, showing hematuria and proteinuria.
Liver function tests: elevated ALT and AST.
Diagnosis
Rift Valley Thermal Diagnosis
diagnosis
According to the epidemiological data and clinical manifestations, a preliminary diagnosis can be made. According to the virus isolation (the serum of the patient is inoculated into the mice for 3 days), or the serum specific antibody titer is increased, the diagnosis can be confirmed.
Same as hemorrhagic fever in Argentina and Bolivia.
Differential diagnosis
Need to be identified with influenza, Japanese encephalitis, viral hepatitis, brucellosis, Q fever, and other various viral hemorrhagic fever.
1. Influenza: Symptoms of systemic poisoning are obvious, manifested as high fever, headache, body aches, respiratory symptoms are mild, high fever lasts 2-3 days after remission, showing bimodal fever, confirmed by virus isolation or serological examination.
2. JE: popular in summer and autumn, mosquito bites, clinically with high fever, disturbance of consciousness, convulsions, respiratory failure and meningeal irritation. Generally no liver damage and bleeding symptoms.
3. Viral hepatitis: It can have chills and fever at the beginning of the disease, and the body temperature is about 38 °C, accompanied by general malaise, loss of appetite, oiliness, nausea, vomiting and discomfort of upper abdominal distension. Severe hepatitis has bleeding tendency, hepatic encephalopathy, and disturbance of consciousness, but no DIC bleeding.
