Comments
INITIAL SYMPTOMS:
In pre-hemorrhagic phase, patients have flu-like illness with fever, myalgia, and headache; [CCDM, p. 43]
FINDINGS:
The case-fatality rate of this tickborne viral disease varies from 2% to 30%. Patients may develop vomiting, abdominal pain, diarrhea, conjunctivitis, petechial rash, and bleeding (gums, nose, lungs, uterus, urinary tract, and gastrointestinal). Laboratory findings include liver enzyme elevations, leukopenia, and thrombocytopenia. [CCDM, p. 43-4] Patients may have flushing of the face and chest, conjunctival injection, and palatal petechiae. The illness may be biphasic with a primary flu-like illness, a few days of remission, and then the secondary hemorrhagic phase. Findings in the second phase may include severe liver injury, bradycardia, pulmonary edema, and epistaxis. Bleeding from IV sites, the nose, and other mucosa is often heavy enough to cause anemia and hypotension. Marked abnormalities of platelet count, transaminase levels, and clotting factors, as well as leukocytosis, predict a fatal outcome. [ID, p. 2144-5] Other findings that are sometimes present: hepatomegaly, stiff neck, and sore throat; [WHO website]
EPIDEMIOLOGY:
The disease occurs where Hyalomma ticks live (tick bites or slaughtering animals infested with ticks). [Harrison ID, p. 1047] Hospital workers may become infected after exposure to blood and secretions. Other cases result from workers handling the tissues of infected animals. Reservoirs include ticks plus amplifying hosts (sheep, cattle, ostriches, goats, wild herbivores, hedgehogs, and hares). [CCDM, p. 43-6] This virus does not replicate to high concentrations in cell cultures, and, therefore, is not likely to be used as a biological weapon. [JAMA]
CASE DEFINITION:
The WHO case definition of acute hemorrhagic fever syndrome includes any 2 of the following: hemorrhagic or purpuric rash, epistaxis, hematemesis, hemoptysis, and blood in the stools. [WHO website]
For updated text and symptoms of infectious diseases, see iddx.com.
Diagnostic
Culture; PCR; Paired sera; "In most patients, virus-specific IgM and IgG antibodies can be detected by indirect IF or EIA on days 7 to 9 of illness, with IgM falling to low or undetectable levels by 3 to 5 months." [ID, p. 2145]