Lassa fever

Introduction to Lasha Lassafever is an acute, contagious international infectious disease. Named after the first discovery in 1969 in the town of Lhasa in northeastern Nigeria. basic knowledge The proportion of illness: 0.005% Susceptible people: no special people Mode of infection: blood transmission, respiratory transmission complication:

Lassa fever cause

(1) Causes of the disease

The Lassa virus is a genus of the genus of the genus of the genus. The Lassa virus is a pleomorphic two-segment RNA virus with an envelope that is sensitive to lipid solvents and detergents.

(two) pathogenesis

The pathogenesis of this disease is still unclear. Severe viremia persists in the febrile phase, neutralizing antibodies appear late and both viruses and specific antibodies are present, suggesting that there may be serious damage to cell-mediated immune function.

Pathological anatomy showed multiple organ congestion, edema, chest, abdominal cavity, pericardium may have bloody exudation, neck, face, shoulder, back skin visible scattered bleeding points and edema, microscopic examination revealed cardiac congestion and interstitial edema, pulmonary congestion, Edema, spleen congestion, white pulp atrophy, lymphoid follicle reduction, liver degeneration, fat infiltration to severe extensive eosinophilic necrosis, the kidney may present focal glomerular necrosis.

Lassa fever prevention

The prevention of Lassa fever mainly takes the following measures.

1. Control the source of infection.

Mainly for rodent control and environmental remediation, reducing mouse density.

2. Cut off the route of transmission.

Mainly for the prevention of rats, avoid direct contact with rodents and their excrement.

3. Protect susceptible populations.

There are currently no vaccines available, mainly with personal protective measures, and family members and medical staff are protected from contact with blood, body fluids and excretions.

There is no specific drug treatment for this disease, mainly for symptomatic treatment. Should be strictly isolated for at least 3-4 weeks

There is no vaccine at present, and the prognosis is mainly anti-mouse, rodent control, and personal protection.

Lassa fever complications Complication

Hypotension shock, acute renal failure and severe bleeding.

Lassa fever symptoms common symptoms dizziness, diarrhea, abdominal pain, congestion, abdominal tenderness, maculopapular joint pain, hypotension, difficulty swallowing, shivering

The incubation period is 7 to 10 days. There is no specific symptom in the early stage of the disease. There may be fever, chills, general malaise, headache and diffuse muscle and joint pain, sore throat, difficulty swallowing, vomiting, abdominal pain, diarrhea, cough and chest pain. There are dizziness, tinnitus, physical examination of facial edema, conjunctival congestion, exudative pharyngitis, hypotension and low pulse pressure, abdominal tenderness, sometimes skin macules, and the recovery period is 2 to 4 weeks.

Lassa fever inspection

1, general inspection

(1) Blood routine examination: white blood cell count and neutrophil elevation in severe cases.

(2) urine routine examination: about 2/3 cases have proteinuria.

(3) Biochemical examination: AST, ALT, BUN may be elevated.

2, school check

(1) Serum-specific IgM antibody: It is detected by the method of IgM capture ELISA. IgM antibodies generally appear at week 2 after onset.

(2) Serum-specific IgG antibody: detected by ELISA, immunofluorescence (IFA), etc., but the sensitivity of IFA is worse than ELISA. In general, IgG antibodies appear in the third week after onset.

3, the original inspection

(1) Serum specific antigen: mostly detected by ELISA. In general, Lassa virus antigens appear in the first week after onset.

(2) Nucleic acid detection: detection by nucleic acid amplification such as RT-PCR. Viral nucleic acid can be detected in the serum of most patients within 5 days of the course of the disease, and can still be detected in more than half of the patients within 30 days after the onset of the disease.

(2) Virus isolation: Collect serum or whole blood samples from patients within 14 days of onset, and use Vero cells for virus isolation.

Lassa fever diagnosis

diagnosis

Because Lassa fever lacks specific performance, it is difficult to diagnose.

1. Patients with fever, purulent pharyngitis and proteinuria are about 80% likely to develop Lassa fever.

2. The Lassa virus was isolated, the anti-Lassa virus antibody was increased by 4 times, the IgM antibody was positive, and the IgG antibody titer was above 1:512, and any one of them was positive.

Differential diagnosis

Identification with the rift heat phase. Rift Valley fever: The incubation period (from infection to symptoms) is 2 to 6 days. The infected person either has no detective symptoms or a mild disease reaction, and has a fever, sudden fever, muscle pain, joint pain and headache.

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