Hantavirus

Background

Enveloped, single-stranded RNA virus within the order Bunyavirales, family Hantaviridae
Acquired by inhalation of contaminated rodent urine or feces, and possibly by bites
Essentially worldwide, though New World viruses tend to cause hantavirus pulmonary syndrome and Old World viruses tend to cause hemorrhagic fever with renal syndrome
- In Canada, no cases have been described east of Saskatchewan; specifically, no cases of HPS have been described in Ontario since it became reportable in 2001
Incidence of HPS peaks in summer months (in North America)

Caused by Old World hantaviruses, such as Hantaan, Dobrava, Seoul, Puumala, and other Old World hantaviruses
Fever, thrombocytopenia, and AKI caused by acute interstitial nephritis
Also headache, abdominal pain, low back pain, dizziness, and blurred vision
Can have conjunctival injection and petechiae on upper trunk and soft palate
Febrile phase lasts 4 to 7 days of acute, severe illness, followed by hypotensive, oliguric, and polyuric phases
Leukocytosis and thrombocytopenia seen on CBC
Mortality up to 5%

Caused by New World hantaviruses such as Sin Nombre, Bayou, and Black Creek Canal
Prodrome of fever followed 4 to 5 days later by shock and pulmonary edema
- Prodrome may include myalgias, abdominal pain, and gastrointestinal symptoms
- Respiratory failure can develop quickly and often requires intubation
Chest x-ray almost always shows bilateral infiltrates suggestive of ARDS
Elevated hematocrit (from third-spacing), leukocytosis, atypical lymphocytes, thrombocytopenia (with severity predicting mortality), prolonged PTT, and mild elevations in AST and LDH
- Creatinine may be elevated, but not as severe as HFRS
Case fatality rate is about 35%

Serology usually positive by presentation (both IgM and IgG)
PCR or immunohistochemical staining are both possible
Viral culture is difficult
Of note, it is a biosafety risk group 3 pathogen, which requires special precautions in the lab