Makindo Medical Notes

🦠 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.