Lassa Fever

Lassa fever is an often fatal infection with arenaviruses, which is found primarily in West Africa. You can run with the involvement of different organ systems. The diagnosis is made by serological studies and PCR. The sessions are held u. a. iv with ribavirin

(See also Overview of infections by Arbovirus, Arena virus and filovirus.)

Lassa fever is an often fatal infection with arenaviruses, which is found primarily in West Africa. You can run with the involvement of different organ systems. The diagnosis is made by serological studies and PCR. The sessions are held u. a. iv with ribavirin (See also Overview of infections by Arbovirus, Arena virus and filovirus.) Lassa fever outbreaks occurred in Nigeria, Liberia and Sierra Leone. There were also cases in Germany, imported into the United States and Great Britain. The reservoir is mastomys natalensis, a rat, which is common in Africa in houses. Most human cases of the disease likely result from a contamination of food with urine or feces of rodents, a transmission from person to person through urine, feces, saliva, vomit or blood, however, is also possible. Based on serological data have indigenous people in endemic areas a very high rate of infection (much higher than their rate of hospitalization for Lassa fever), suggesting that many infections are mild and self-limiting. Some observational studies of missionaries who were sent to endemic areas, however, show that they have a much higher rate of serious disease and mortality. The Centers for Disease Control and Prevention (CDC) estimate that about 80% of infected people have mild disease and about 20% a severe multisystem disease. Symptoms and signs The incubation period is 5-16 days. The symptoms of Lassa fever begin gradually increasing fever, weakness and malaise, and gastrointestinal symptoms (eg, nausea, vomiting, dysphagia, abdominal pain.); Symptoms and symptoms of hepatitis may also occur. Over the next 4-5 days the symptoms are progressing, and there is sore throat, cough, chest pain and vomiting. The neck pain is worse during the first week; it can white or yellowish exudate form on the tonsils, often unite to pseudomembranes. In 60-80% of patients develop systolic blood pressures of <90 mmHg with venous pressures of <20 mmHg, a relative bradycardia is possible. In 10-30% of patients develop a facial - and neck swelling and conjunctival edema. Occasionally, the patients' tinnitus, epistaxis, gingival bleeding, bleeding from venipuncture sites, maculopapular rash, cough and dizziness. A hearing loss develops in 20% and is often permanent. In surviving patients occurs within 4 to 7 days to become afebrile. Progression to severe disease results in shock, delirium, rales, pleural effusion and occasionally generalized seizures. Occasionally the pericarditis. The severity of fever and transaminases correlate with the severity of the disease. Long-term consequences are for. B. alopecia, iridocyclitis and temporary blindness. Diagnostic PCR or serological tests Suspicion of Lassa fever is at potentially exposed patients when they undergo virological prodromal stage, which is followed by otherwise unexplained diseases of various organ systems. Liver parameters, urine tests, serological tests and possibly a blood count should then be initiated. There is often a proteinuria, which can be very pronounced. The AST and ALT levels increase (about 10 times of the standard), as is the LDH levels. The fastest diagnosis is performed by PCR, but the detection of Lassa-IgM antibodies or a 4-fold increase in IgG antibody titer by indirect fluorescent antibody test is also diagnostically conclusive. Although the virus is be cultured in cell cultures, a cell culture is carried out routinely. Due to the risk of infection, particularly in patients with hemorrhagic fever, the cell cultures may only be processed in a laboratory Biosafety Level 4 (BSL 4). Suspicion of lung involvement, a chest X-ray image to be customized, which may have a basal pneumonitis and pleural effusions. Prognosis Approximately 7-31 days (12-15 days on average) after the onset of symptoms occurs either for recreation or death in general. In patients with severe multisystem disease, the mortality is 16 to 45%. During pregnancy, the disease is difficult. In pregnant women or women who have given birth within the last month, the mortality rate is 50-92%. Most pregnant women lose the fetus. Ribavirin therapy When starting with ribavirin within the first 6 days, it can reduce mortality up to 10 times. Treatment with Ribavirin i.v. 30 mg / kg (Maximum 2 g) initial dose, followed by 16 mg / kg i.v. (Maximum 1 g / dose) every 6 hours for 4 days, then 8 mg / kg i.v. (Maximum 500 mg / dose) every 8 h for 6 days. Anti-Lassa fever plasma was attempted in very ill patients, but has not shown to be effective and is not currently recommended. Supportive therapy incl. Compensation of fluid and electrolyte disorders is imperative. Infected pregnant women, especially during the third trimester of pregnancy seems to reduce the maternal mortality pregnancy interruption. Prevention To avoid transmissions are standard hygiene measures recommended airborne isolation (incl. Goggles, negative pressure rooms and positive pressure HEPA respirators), and monitoring of contacts. There is no vaccine available. Important points that Lassa fever is usually transmitted via contaminated with the feces of rodents food, but a transfer from person to person through urine, feces, saliva, vomit or blood is also possible. Symptoms may progress from fever, weakness, malaise and gastrointestinal symptoms to exhaustion with a sore throat, cough, chest pain and vomiting; sometimes shock, delirium, rattles and pleural effusion; and occasionally cause serious illness and shock. Use for most fast diagnoses PCR, as well as antibody tests can be used. Lassa fever is severe during pregnancy; Most infected pregnant women lose the fetus. When starting with ribavirin within the first 6 days, it can mortality by up to 10-fold decrease. Supportive therapy incl. Compensation of fluid and electrolyte disorders is imperative.

Health Life Media Team

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