OVERVIEW
Argentine hemorrhagic fever is a rodent-dominated, naturally occurring epidemic caused by Hatchetin and Matyabo viruses, respectively. Clinical features include fever, severe myalgia, hemorrhage, shock, neurological abnormalities, and leukopenia and thrombocytopenia.
Etiology
Hatnin belongs to the same genus as Machupo virus, and is named for its sand-like appearance on ultrathin slices. Hatting virus is a ribonucleic acid (RNA) virus with a diameter of 60 to 280 nanometers, an average of 110 to 130 nanometers, and a spherical, oblate spherical, or multifarious shape. On the outer membrane there are 2 to 10 length of about 6 nanometers, ball and stick protrusions, the virus particles contain 2 to 10 diameter 20 to 25 nanometer sand-like particles.
The virus is pathogenic to neonatal mice and gophers, so it can be used to isolate the virus. Matyubo virus is similar to Hatanin virus in morphology and biological characteristics.
The direct damaging effects of the virus are now considered to be primary. The virus enters the human body and produces viremia through replication and proliferation, causing damage to capillary endothelial cells throughout the body and increasing vascular permeability and fragility, resulting in a series of clinical symptoms such as hemorrhage, edema, and shock.
Symptoms
Incubation period of 6 to 14 days. The onset of disease is slow.
In the first week of illness, discomfort gradually appears, body temperature rises gradually, up to 39 ℃ on the third day, severe headache, lumbago, muscle and joint pain, anorexia, nausea, vomiting, epigastric pain, some patients with orbital pain, and there may be constipation or diarrhea. Physical examination of the face, neck and upper chest flushing, petechiae, ecchymosis can be seen in the skin of the upper chest, upper arm and axilla, and the lymph nodes are moderately enlarged. Conjunctival congestion, periorbital edema, oropharyngeal mucosal congestion, fine petechiae, blisters of varying sizes on the soft palate, and gingival congestion or bleeding were noted. 1/5 cases presented with specific neurological symptoms on day 4-6, which were manifested as disorientation, intentional tremor of the hands and tongue, moderate ataxia, cutaneous sensory hypersensitivity, and decreased tendon reflexes and muscle tone. Female patients often have mild to moderate uterine bleeding and may present as the first symptom of Argentine hemorrhagic fever. A few patients have an acute onset of illness that appears to be an acute abdomen leading to surgery.
Hypotension, oliguria, and varying degrees of dehydration occur at the end of the first week as the fever subsides rapidly, with gradual recovery after 48 hours. Comatose shock may occur in severe cases, and a few die in 48 to 72 hours. Blood tests show a decrease in white blood cells and platelets, which gradually recovers after the fever subsides. Proteinuria and tubular pattern may be present. Blood sedimentation is normal.
In the 2nd disease week, 70% to 80% of patients have a reduction in the above symptoms and signs, but weakness, alopecia and memory loss require a recovery period of 1 to 3 months without sequelae. 20% to 30% of patients develop severe bleeding from the stomach, intestines, nose, gums and uterus or neurological damage (impaired consciousness, ataxia, excitation and tremor, or even delirium, convulsions and coma), or both, in 8 to 12 disease days, which can result in death.
Examination
1. Blood tests
Blood picture: white blood cell count and platelet decrease, gradually recovering after the fever subsides. Blood sedimentation is normal.
2. Urine routine
Proteinuria and tubular pattern may be present.
3. Virus isolation
①Take the patient’s blood (acute fever stage) lymphoid tissue (dead cases) inoculated in mice, guinea pigs, and green monkey kidney cells, golden gopher kidney cells monolayer culture, isolate the virus. ② Taking peripheral blood mononuclear lymphocytes from patients with suspected Argentine hemorrhagic fever and inoculating them with Vero cells in monolayer culture is the most sensitive method for isolating Hatting virus.
4. Immunohistochemical methods
Such as immunofluorescence or peroxidase-antiperoxidase complex method (PAP method), the results can be produced within 1 to 3 days, which is conducive to early diagnosis.
5. Serologic tests
Indirect fluorescence test and empty spot reduction test, detect specific antibody, used for early diagnosis. Complement binding test, can not be used for early diagnosis, but can be used to screen Argentine hemorrhagic fever immune plasma donors.
Diagnosis
Fever, severe headache, lumbago, musculoarticular pain, orbital pain, epigastric pain, skin petechiae, ecchymosis, and uterine hemorrhage, facial flushing, conjunctival congestion, periorbital edema, pharyngeal mucosal congestion and the appearance of small blisters, and a decrease in the white blood cell count and thrombocytopenia are seen in persons in endemic areas (Argentina or Bolivia) or those who have entered an endemic area or have a history of exposure to rodents. Proteinuria and tubular pattern appear, while the blood sedimentation is normal, the diagnosis can be made.
Treatment
1. General supportive and symptomatic treatment
Patients should be isolated and their blood and excreta should be sterilized. Strengthen support, symptomatic treatment, maintain water, electrolyte balance, for bleeding, shock, neurological symptoms, as well as overlapping infections, symptomatic treatment.
2.Special treatment
The application of high-efficiency immune plasma can neutralize viremia, reduce the degree of hemorrhage and neurological, damage, and reduce the death rate. However, in the treatment, 8%~10% of patients may have posterior neurological syndromes, such as fever, cerebellar function abnormalities, which can be relieved by themselves.