1. HEMORRHAGIC FEVERS Sorokhan MD, PhD Bukovinian State Medical University Department of the infectious diseases and epidemiology

5. Signs and symptoms Clinical course. Human infections with Ebola virus is characterized by an incubation period of 3-8 days in primary cases and slightly longer in secondary cases. However, cases with incubation periods of 19 and 21 days have been observed. The onset of clinical symptoms is sudden. Severe headache, arthralgias or myalgias, fever with or without chills, anorexia, and asthenia occur early in the disease. Gastrointestinal symptoms, including abdominal pain, nausea and vomiting, and diarrhea, soon follow. Evidence of mucous membrane involvement includes conjunctivitis, odynophagia or dysphagia, and bleeding from multiple sites in the gastrointestinal tract. Terminally ill patients often are obtunded, anuric, tachypneic, normothermic, and in shock. Although the mechanism is unclear, hiccups have been noted in fatal cases of Ebola.

6. Physical examination The findings upon physical examination depend on the stage of disease in which patients present. Early in the disease, patients may present with fever, pharyngitis, and severe constitutional signs and symptoms. A maculopapular rash, more easily seen on white skin than on dark skin, may be present around day 5 of infection and is most evident on the trunk. Bilateral conjunctival injection is also common. Late in the disease, patients often develop an expressionless facies. At this point in the disease, bleeding from intravenous puncture sites and mucous membranes is common. Myocarditis and pulmonary edema also are seen in the later stages of the disease. Terminally ill patients often die tachypneic, hypotensive, anuric, and in a coma.

7. Differential Diagnoses The diseases most frequently confused with Ebola hemorrhagic fever are Malaria, Marburg Hemorrhagic Fever, Other Hemorrhagic Fevers, Typhoid Fever, Acute surgical abdomen versus abdominal signs of Ebola hemorrhagic fever, and Crimean-Congo hemorrhagic fever.

8. Laboratory Studies The early phase of infection is characterized by thrombocytopenia, leukopenia, and a pronounced lymphopenia. Neutrophilia develops after several days, as do elevations in aspartate aminotransferase and alanine aminotransferase. Bilirubin may be normal or slightly elevated. With the onset of anuria, blood urea nitrogen and serum creatinine increase. Terminally ill patients may develop a metabolic acidosis that may contribute to the observation that these patients often have tachypnea, which may be an attempt at compensatory hyperventilation. Definitive diagnosis rests on isolation of the virus in tissue culture or PCR.

9. Treatment There is no standard treatment for Ebola hemorrhagic fever. Treatment is primarily supportive and includes minimizing invasive procedures, balancing electrolytes (since patients are frequently dehydrated), replacing lost coagulation factors to help stop bleeding, maintaining oxygen and blood levels, and treating any complicating infections. Convalescent plasma (factors from those that have survived Ebola infection) shows promise as a treatment for the disease. Presently, no specific therapy is available that has demonstrated efficacy in the treatment of Ebola hemorrhagic fever.

10. Prevention In the early stages, Ebola may not be highly contagious. Contact with someone in early stages may not even transmit the disease. As the illness progresses, bodily fluids from diarrhea, vomiting, and bleeding represent a hazard. Due to lack of proper equipment and hygienic practices, large-scale epidemics occur mostly in poor, isolated areas without modern hospitals or well-educated medical staff. Many areas where the infectious reservoir exists have just these characteristics. In such environments, all that can be done is to immediately cease all needle-sharing or use without adequate sterilization procedures, isolate patients, and observe strict barrier nursing procedures with the use of a medical rated disposable face mask, gloves, goggles, and a gown at all times, strictly enforced for all medical personnel and visitors. Presently, no commercially available Ebola vaccines are available.

11. Complications Ocular complications: patients reported ocular pain, photophobia, increased lacrimation, and decreased visual acuity. Survivors have developed the following late manifestations: Myalgias; Asymmetric and migratory arthralgias; Headache; Fatigue; Bulimia; Amenorrhea; Hearing loss; Tinnitus; Unilateral orchitis; Suppurative parotitis. Prognosis The overall prognosis of Ebola is poor. However, patients who survive for 2 weeks often make a slow recovery.

12. Ebola virus

15. Epidemiology Lassa virus is zoonosis and was isolated from rodents of the genus Mastomys. This is probably the most common rodent in equatorial Africa. In these rats infection is in a persistent asymptomatic state. The virus is shed in their excreta (urine and feces), which can be aerosolized. Lassa fever is common in the dry season. Mastomys rodent, natural host of Lassa virus. Image courtesy of the Centers for Disease Control and Prevention.

16. Epidemiology Infection in humans typically occurs via exposure to animal excrement through the respiratory or gastrointestinal tracts. It is possible to acquire the infection through broken skin or mucous membranes that are directly exposed to infective material. Like other hemorrhagic fevers , Lassa fever can be transmitted directly from one human to another, presenting a disease risk for healthcare workers. It can be contracted by an airborne route or with direct contact with infected human blood, urine, or semen. Transmission through breast milk has also been observed.

20. Treatment The antiviral drug ribavirin is used in Lassa fever. Supportive care related to blood pressure monitoring/control and careful attention to fluid and electrolytic balance can be lifesaving. Medication Ribavirin (Virazole) - 2 g (30 mg/kg) IV initially; 1 g (15 mg/kg) IV q6h for 4 d; then 500 mg (7.5 mg/kg) IV q8h for 6 d. Suggested prophylactic dose: 600 mg PO qid for 10 d.

24. Lassa virus

25. Thank you for your attention!