Argentina hemorrhagic fever
The Argentina hemorrhagic fever – natural and focal from group of the South American hemorrhagic fevers, caused by RNA - the containing virus Junin. Act as the leading clinical manifestations a hemorrhagic syndrome with bleedings of various localization, the expressed intoxication. Diagnostics is based on detection of the activator and specific markers in blood serum. Etiotropny treatment consists in introduction of immune plasma. Good results are shown by purpose of a ribavirin. Taking into account the developed violations symptomatic therapy is appointed.
Argentina hemorrhagic fever
Junin is the center of hemorrhagic fever a damp ecosystem of a pampas of Argentina. Flashes of incidence happen annually from February to June to peak in May. Most often men are ill, the infection is more widespread among country people. The most part of the diseased – people of working-age. Annually on average about 4000 people are surprised, during flashes the number of infected can reach 20000. About 10% of local population are seropozitivny without infection demonstration in the anamnesis. In view of active immunization of inhabitants of this region it is possible to control incidence with reduction of frequency of episodes with a heavy current recently. As this inoculation is not included into the list obligatory at entry into Argentina, cases of infection of tourists became frequent.
Reasons of the Argentina hemorrhagic fever
The causative agent of an infection – the RNA-containing Junin virus from the family Arenavirus of the Arenaviridae family. The virus perishes under the influence of cleaners, Ural federal district, however long remains in the lyophilized state. Homyakoobrazny rodents, and also the sick person are the tank, and also a source of an infection. Between rodents the activator is transferred inoculable with stings of gamazovy pincers. Getting into blood, the virus causes the latent course of a disease and an asymptomatic viremiya in hamsters. The pathogen from an organism of rodents is allocated with urine.
The infectious agent comes in the air and dust way at inhalation of the dust polluted by rodents to a human body and also at realization of the fecal and oral mechanism with the infected food and water, at sexual contact and through the injured skin. At a sting of the tick infected with a virus, the disease at the person does not develop. Cases of vnutrilabaratorny infection with an aspiration way with development of manifest forms or an asymptomatic current are annually described. After the postponed disease resistant immunity is formed.
The mechanism of development of the Argentina hemorrhagic fever is up to the end not studied. Getting in alveolar macrophages and bronkhopulmonalny lymph nodes, the Junin virus gematogenno and limfogenno extends on all organism. The pathogen is fixed in cages of reticuloendothelial system, damaging them, thereby promoting leucio-and thrombocytopenia. The limfadenopatiya develops, in lymphoid follicles the atrophy, a necrosis is observed. Damage of a wall of capillaries leads to emergence of a hemorrhagic syndrome, gipovolemichesky shock. Damage of vessels of internals promotes violation of their function. Depending on virus loading serious conditions can develop as asymptomatic forms with increase of a caption of antibodies, and.
Symptoms of the Argentina hemorrhagic fever
The incubatory period after infection makes about 7-14 days. The disease begins gradually, nonspecific symptoms appear: fever, weakness, indisposition, headache, artralgiya, mialgiya. For a short period body temperature increases to febrilny figures, there is an enantema on a conjunctiva, mucous a mouth. Objectively face reddening, necks, an injection of vessels skler is defined, the limfadenopatiya, can seldom appear hemorrhagic rash. Bradycardia is characteristic of the first stage of a disease, myocarditis quite often develops.
Duration of the feverish period makes about 10 days. Further demonstrate symptoms of a hemorrhagic syndrome: bleeding of gums raises, nasal bleedings, a gematuriya, melena are noted. Arterial pressure falls to 60 mm of mercury., at massive bleedings hemorrhagic shock develops. Emergence of symptoms of defeat of TsNS with increase of neurologic deficiency (excitement, a stupor, symptoms of encephalitis) is possible. The period of a convalescence makes from 2 weeks to several months.
The most frequent complication is hemorrhagic shock. At shock of heavy degree development of polyorgan violations (sharp renal, heart, respiratory failure) is probable. Besides, defeats of TsNS of various character with accession of neurologic syndromes (encephalopathy, encephalitis) are possible. The imparted patients after the postponed infection sometimes have a tranzitorny alopetion. Rather often against the background of a leykopeniya and damage of a capillary wall arise bronchial pneumonia. Hypostasis of lungs is the most frequent cause of death. Due to the vaccinal prevention introduction severe forms of a course of a disease meet more and more seldom.
At suspicion of hemorrhagic fever consultation of the infectiologist with the subsequent hospitalization in the patient in intensive care unit of infectious diseases hospital is necessary. During fizikalny survey of specific symptoms for this viral infection it is not observed. The obshcheintoksikatsionny syndrome, reddening, hypostasis of a neck, person attracts attention, existence of petekhialny rash, a limfadenopatiya is possible. Emergence of conjunctivitis, an enantema on a mucous membrane of a mouth is characteristic. In diagnostics the following clinical laboratory methods are used:
- General and biochemical research of material. In view of damage of cages of reticuloendothelial system to OAK existence trombotsito-and leykopeniya is noted. Due to defeat of a vascular wall and an esktravazation of a liquid part of blood blood condensation signs are observed. In the general analysis of urine – a proteinuria. Daily losses of protein with urine can reach 10 g. At emergence of polyorgan insufficiency in blood the corresponding markers (ALAT, ASAT, urea, creatinine) raise.
- Definition of infectious agents. For identification of specific antibodies blood is taken in 2 weeks from the beginning of a disease. This method is retrospective rather. Use reaction of binding of a complement, reaction of an indirect immunofluorescence, hemagglutination braking reaction. For detection of a virus investigate pharyngeal washouts, I wet; take up to 7 days from an onset of the illness. The most sensitive method for detection of the activator at early stages is PTsR with the return transcription.
Considering a relative rarity of this nosology outside endemic areas and not specificity of initial symptoms, diagnosis can cause considerable difficulties. Differentiation is carried out with other hemorrhagic fevers, in particular, with South American (Bolivian, Venezuelan, Brazilian). In intoxication stage in lack of the expressed hemorrhagic syndrome it is necessary to exclude flu, arboviral infections, sepsis, and at the height of a disease – hemorrhagic diathesis. Clarification of the anamnesis of a disease, and also comparison of data of a clinical picture to results of analyses allows to establish the correct diagnosis and to appoint the corresponding treatment.
Treatment of the Argentina hemorrhagic fever
Treatment has to be carried out in the conditions of isolation of the patient under control of the infectiologist. At accession of complications consultation of profile experts (the neurologist, the pulmonologist, the nephrologist, the cardiologist) can be required. Observance of a high bed rest is necessary. The main method of therapy is transfusion of plasma of rekonvalestsent. This way yields the best results at the initial stages of a disease (up to 8 days).
There are data on positive results of treatment ribaviriny. This way is especially urgent in lack of immune plasma. Under WHO recommendations drug is injected intravenously in the first day in a dose of 30 mg/kg once, further 15 mg/kg of 4 times/days 4 days and to 7,5 mg/kg/days are 6 days. Symptomatic treatment with correction of the developed violations (dezintoksikatsionny therapy, compensation of volume of blood, application of cardiovascular means, febrifugal medicines, correction of violations of system of a hemostasis) is in parallel carried out.
Forecast and prevention
At in time the recognizable disease and the correct treatment the forecast favorable. In case of development of severe forms duration of the Argentina hemorrhagic fever makes about 11 days, and the lethality reaches 15%. Actions of nonspecific prevention include fight against rodents in endemic areas by use of toxic agents, special traps. Besides, application of respirators at dust works is necessary. Vaccination of locals allows to control the course of incidence. Today use a live attenuirovanny vaccine, check of experimental samples is conducted. Use of a ribavirin as the emergency prevention is not recommended. The exception is made by the pregnant patients contacting to the patient.