Hantavirus infections
🦠 Hantavirus infection is a potentially fatal rodent-borne zoonosis that can cause two distinct syndromes:
Haemorrhagic fever with renal syndrome (HFRS) in the Old World 🌍, and
Hantavirus pulmonary syndrome (HPS) in the New World 🌎.
📖 About
- Hantaviruses are members of the Bunyaviridae family – single-stranded, enveloped, negative-sense RNA viruses.
- Natural reservoir = rodents (rats, mice, voles) which excrete virus in urine, faeces and saliva.
- Human disease ranges from AKI with haemorrhage ➝ to severe ARDS-like pulmonary syndrome.
- Case fatality: ~1% (mild Puumala in Europe) up to 40% (HPS in the Americas).
🦠 Aetiology
- Zoonotic viral transmission via inhalation of contaminated rodent excreta/dust.
- Rodents are asymptomatic carriers and shed virus lifelong.
- Occupational/at-risk groups: farmers, forestry workers, lab staff, pet rat owners.
- Rare person-to-person transmission (Andes virus in South America).
🌍 Major Viruses & Geography
- Haantan virus → East Asia (China, Korea, Russia). Severe HFRS.
- Puumala virus → Scandinavia, Western Europe, Russia. Causes “nephropathia epidemica” (mild HFRS).
- Dobrava virus → Balkans. Severe HFRS.
- Seoul virus → Worldwide, carried by Rattus norvegicus. Seen even in UK pet rat outbreaks.
- Sin Nombre virus → Southwestern USA. Main cause of HPS.
- Andes virus → South America. Severe HPS; person-to-person spread reported.
🩺 Clinical Presentation
- Incubation: usually 2–4 weeks (range 2 days – 8 weeks).
- Prodrome: fever, chills, headache, myalgia, nausea, abdominal pain.
- HFRS (“Old World”): fever → shock → oliguria → diuresis → convalescence. Renal impairment, haemorrhage, thrombocytopenia.
- HPS (“New World”): fever → cough → rapidly progressive pulmonary oedema, ARDS-like picture, hypotension.
- Mortality: HFRS 1–15%, HPS up to 40%.
❓ Differentials
- Other viral haemorrhagic fevers (Ebola, Lassa, Crimean-Congo).
- Leptospirosis (Weil’s disease).
- Sepsis with ARDS.
- Glomerulonephritis with AKI.
🧪 Investigations
- FBC: thrombocytopenia, raised haematocrit.
- U&E: AKI, raised creatinine/urea.
- LFTs: mild transaminitis.
- CXR: pulmonary oedema (HPS).
- ABG: hypoxia in HPS.
- Viral serology (IgM/IgG) or PCR for hantavirus RNA.
💊 Management
- Supportive only – no licensed antiviral therapy. Ribavirin has limited benefit in early severe HFRS (not HPS).
- 🏥 Many require ITU care: ventilatory support for HPS, renal replacement therapy for HFRS.
- Fluid balance is critical – avoid fluid overload in HPS.
- Prevention: rodent control, hygiene (wash hands after handling rats/cages), use protective masks/gloves in endemic settings.
📌 Clinical Pearls
- Think of hantavirus in a patient with ARDS + thrombocytopenia + rural/rodent exposure.
- Puumala (“nephropathia epidemica”) is endemic in Northern Europe – consider in unexplained AKI with fever.
- Unlike sepsis, shock in HPS is primarily due to capillary leak, not vasodilation.
📚 References
- CDC Hantavirus overview.
- UKHSA – Seoul hantavirus in pet rats (UK outbreaks).
- UpToDate: Clinical features and management of hantavirus infections.
