Hantavirus risk level in New Hampshire is currently very low. The dominant strain is Sin Nombre virus. This page is part of Hanta Hub's state-by-state risk profile, updated daily during the 2026 MV Hondius outbreak.
HPS extremely rare. Cabin clean-outs in spring should still follow CDC guidance.
As of 2026-05-11, the 2026 MV Hondius hantavirus cluster has produced 10 cases (8 PCR-confirmed Andes virus, 2 probable) and 3 deaths. While the outbreak is centred on a Dutch-flagged expedition cruise ship, several US states — including some monitoring returned MV Hondius passengers — are conducting active surveillance. Whether New Hampshire has an MV Hondius–linked monitoring case or not, the background hantavirus picture in New Hampshire reflects the established endemic strains in the region.
The hantavirus species most associated with New Hampshire is Sin Nombre virus. In the continental United States, the overwhelmingly dominant clinical species is Sin Nombre virus, hosted by deer mice (Peromyscus maniculatus). In the southeast, Bayou and Black Creek Canal viruses also occur. In the Andes virus context — relevant only for travellers returning from southern Argentina or Chile or for MV Hondius–exposed individuals — the natural reservoir is not present in New Hampshire.
For an in-depth comparison of these strains, see Andes Virus vs. Sin Nombre Virus.
Prevention is built around three principles: keep rodents out of living spaces, never dry-sweep or vacuum rodent droppings, and use respiratory protection during any cleanup of rodent-affected areas.
If you live in a rural area, store firewood at least 20 feet from the house, seal gaps around foundations and utility entries, and use snap traps rather than glue traps (which stress rodents and increase aerosol risk). When opening a closed cabin in spring, ventilate for 30 minutes before entry, wet-disinfect any visible droppings with a 1:10 bleach solution, and wear an N95 respirator, gloves, and eye protection during the cleanup.
Any flu-like illness with fever, severe muscle aches, and shortness of breath after possible rodent exposure should be treated as a medical emergency. Tell your provider about any rural cabin clean-up, exposure to old structures, or travel through endemic regions in the previous one to eight weeks.
Hantavirus pulmonary syndrome has a 36% case fatality rate in the Americas; early hospitalisation substantially improves survival.
→ See the live MV Hondius tracker, full timeline, and 15 hantavirus news sourcesIn New Hampshire the typical background hantavirus risk is very low. Confirmed HPS cases in the state depend largely on rural rodent populations and seasonal cabin clean-out patterns. The current MV Hondius cluster is a separate, contained event involving Andes virus.
No. WHO, the CDC, and state health authorities have not issued travel advisories for New Hampshire or any other US state in connection with the 2026 outbreak. Standard hantavirus prevention applies as it always has.
The 2026 MV Hondius cluster involves Andes virus, the only hantavirus with documented human-to-human transmission. The natural rodent reservoir for Andes virus is in southern South America, not in the United States.
Diagnosis is by serology (IgM and IgG antibody testing) and PCR. State public health laboratories and the CDC support diagnostic testing when HPS is clinically suspected.