Lassa fever

Lassa fever - an acute viral disease of the zoonosis with natural foci group. It is characterized by severe, high mortality, hemorrhagic syndrome, ulcerative pharyngitis, respiratory lesions, kidney, central nervous system, myocarditis.

Etiology, pathogenesis. The causative agent belongs to adenavirusam. The reservoir of infection in nature is multimammate rat, widespread in West Africa. Infection alimentary and airborne droplets can occur through the skin microtrauma, and by inhalation of dust. The causative agent of fever Laos is one of the most dangerous viruses of human, working with them requires strict precautions. The virus is relatively stable in the environment. In place of the gate of the infection is not detected changes. Characterized by hematogenous dissemination of the virus and damage many organs and systems. Increased vascular fragility, there are profound hemostasis disorders and developing disseminated intravascular coagulation syndrome. Hemorrhage most pronounced in the intestine, liver, myocardium, lung, brain.

Symptoms within. The incubation period lasts 3-17 days. Prodromapnyh no symptoms. The disease begins relatively slowly. With each passing day increases the severity of fever and symptoms of intoxication. In the early days, patients noted general weakness, fatigue, malaise, muscle and mild headache. The body temperature rises, and after 3-5 days, reaches 39-40 C. The fever may last for 2-3 weeks. Increased and symptoms of intoxication (asthenia, myalgia, disorders of consciousness). Face and neck hyperemic, sometimes pasty, scleral vessels injected. In the initial period the majority of ball (80%) displayed the characteristic lesion throat - on the bow of the tonsils and soft palate marked necrotic lesions and ulcerative changes yellowish-greyish color, bright area surrounded by redness. Their number then increased, they may merge, are sung may resemble fibrinous. On the 5th day of the disease may have pain in the epigastric region, nausea, vomiting, abundant liquid, watery stools. Sometimes it is developing dehydration. In severe forms of the disease na 2nd week symptoms of intoxication increases sharply, joined pneumonia, pulmonary edema, myocarditis, swelling of the face and neck, hemorrhagic syndrome. During this period letalnny possible outcome.

Early revealed generalized lymphadenopathy at the end of the 1st week of rash appears (roseola, papules, patches). Clinically and radiographically revealed pneumonia, pleural effusion often. There have been a pain in the epigastric region, copious watery stools. The liver is enlarged. Sometimes it is developing ascites. In the blood, leukopenia, thrombocytopenia, increased aminotransferases.

Diagnosis. Of great importance are the epidemiological data (zndemichnoy stay in the area for no more than 17 days before the onset of illness). Differentiate necessary for many diseases -. Tonsillitis, diphtheria, severe pneumonia, yellow fever, malaria, etc. A specific confirmation of the diagnosis is virus isolation (in special laboratories) and serology (DGC RIF).

Treatment. All the patients are subject to exclusion. No causal agents. The key is to pathogenetic therapy. Rehydration is carried out (see. Cholera} / drip is administered 60 to 80 mg of prednisone, 400-800 ml reopoliglyu-kin. Oxygen, a complex of vitamins. Treatment of hemorrhagic syndrome, see. P. 199. Forecast serious, lethality of 36-67%. Prevention. strict preventive measures, taking into account droplet and contact transmission paths. The patient was isolated in a box, and if possible in special plastic or glass-metal cab with self-contained life support. The staff must work in protective clothing (gowns, respirators, goggles ..) Carry out thorough ongoing and final disinfection danger are blood and urine, so not only bacteriological, but also the usual clinical and biochemical studies conducted in compliance with all security measures Duration isolation of patients -. not less than 30 days from the onset of the persons in contact. patients with Lassa fever, conduct surveillance for 17 days (the maximum incubation period). If you need to transport patients comply with strict measures of prevention of dispersion of infection. Specific preventive maintenance is not developed.