Hantaviruses — Questions

Hantaviruses are acquired by inhaling aerosols of infected rodent urine, droppings and saliva, typically when disturbing contaminated dust indoors.

They are not arthropod-borne, so tick and mosquito bites are irrelevant, and water and sexual transmission are not significant routes (person-to-person spread is confined to Andes virus).

The kidney bears the brunt in HFRS, giving the oliguric phase of acute kidney injury that is the usual time of death.

The lung is the target in the New World cardiopulmonary syndrome; the liver, heart and brain are not the primary organs, though overlap between the syndromes occurs.

Wet years, driven by the El Nino Southern Oscillation, boost rodent food and numbers, raising human contact and hantavirus cardiopulmonary cases.

Cold dry conditions reduce rodent numbers, and ticks, birds and indoor gatherings are irrelevant to a rodent-borne, non-arthropod virus.

New World hantaviruses, such as Sin Nombre and Andes, classically cause hantavirus cardiopulmonary syndrome, dominated by non-cardiogenic pulmonary oedema and shock.

Haemorrhagic fever with renal syndrome is the Old World counterpart; encephalitis, polyarthritis and hepatitis are not hantavirus syndromes.

South Africa has no documented local human hantavirus disease, and the realistic risk is an imported Andes virus case in a traveller returning from South America.

Local rodents carry only mild native African hantaviruses, not the New World cardiopulmonary strains; hantavirus is a Category 1 notifiable condition; and it is rodent-borne, not tick-borne.

Ribavirin helps HFRS when started early in the course of illness.

It has shown no benefit in the New World cardiopulmonary syndrome, and it is not used for all infections, as prophylaxis, or only in children.

Inactivated vaccines against Hantaan and Seoul viruses are used in parts of Asia, but none is widely licensed elsewhere, so prevention rests on avoiding rodent contact.

There is no worldwide live-attenuated, mRNA or universal childhood hantavirus vaccine, and vaccines against the New World species do not exist.

Serology is the mainstay, and IgM is usually detectable at symptom onset because patients present after the short viraemic phase.

Culture is impractical, there is no antigen skin test, the blood film is not diagnostic, and rodent trapping is an environmental, not a clinical, tool.

Sin Nombre virus is carried by the deer mouse (Peromyscus maniculatus), and its numbers, and human cases, rise in wet years.

The brown rat carries Seoul, the bank vole Puumala, the striped field mouse Hantaan and the yellow-necked mouse Dobrava-Belgrade.

Hantaviruses infect endothelium without killing it, and disease follows from an immune-mediated rise in capillary permeability, so the injury is functional and reversible.

Direct lysis, bacterial co-infection and thrombosis are not the mechanism, and antibody-dependent enhancement is a dengue phenomenon.

Cardiopulmonary syndrome is managed with careful fluid restriction, inotropic support and, in the most severe cases, extracorporeal membrane oxygenation (ECMO), which improves survival in referral centres.

Aggressive fluid loading worsens the pulmonary oedema, corticosteroids and antibiotics are not effective, and dialysis belongs to the renal syndrome.

Seoul virus is distributed worldwide because its reservoir, the brown rat, has followed shipping to every continent, making it the one HFRS agent found far beyond the Old World.

Hantaan and Puumala are regional Old World viruses, Sin Nombre and Andes are New World cardiopulmonary agents.

Andes virus is the only hantavirus with documented person-to-person transmission, which is why a suspected case needs isolation and contact tracing, as in the 2026 cruise-ship outbreak.

Every other hantavirus is acquired solely from rodent excreta, with humans a dead-end host.

Puumala virus causes the mild HFRS historically called nephropathia epidemica, and accounts for most of the European caseload.

Hantaan and Dobrava-Belgrade cause severe HFRS, Seoul a moderate form, and Andes is a New World cardiopulmonary agent.

The human-pathogenic hantaviruses belong to the genus Orthohantavirus in the family Hantaviridae, a true taxonomic grouping.

Unlike “arbovirus”, the name reflects shared ancestry, not ecology; the wider family also infects shrews, moles, bats and lower vertebrates; and the genome is segmented negative-sense RNA, not DNA, in the order Bunyavirales rather than the Flaviviridae.