Doctors treating hantavirus have long focused on the lungs. A review published last week argues that the nervous system deserves attention too, and that some of the damage may not become apparent for weeks or months after a patient appears to recover.
The review in JAMA Neurology, written by Avindra Nath, MD, of the National Institutes of Health, synthesizes existing case reports and small studies on brain and nerve involvement in hantavirus infection. It was published after the Andes hantavirus outbreak aboard the cruise ship MV Hondius, which infected 11 people and killed three earlier this year, as CIDRAP reported.
Two things should be clear from the outset. Neurologic complications are uncommon. And this is a review of published literature, not new patient data. It organizes what is already known rather than generating fresh findings.
What the Review Covers
Hantaviruses are rodent-borne and usually spread through contact with infected rodent urine, droppings or saliva. Andes virus is the only strain known to be capable of person-to-person transmission.
The review divides the illness into two major syndromes with different neurologic profiles.
Hantavirus pulmonary syndrome, or HPS, occurs most often in the Americas and mainly affects the lungs and cardiovascular system. Its mortality rate runs from 35% to 50%. Neurologic problems in HPS patients are typically secondary to critical illness rather than direct viral attack on the nervous system, and can include headache, delirium and seizures. Brain hemorrhage and post-viral encephalitis are described but rare.
Hemorrhagic fever with renal syndrome, or HFRS, is endemic to Asia and eastern Russia and is more commonly associated with direct neurologic effects. In a review of 811 patients infected with the Puumala strain, 97% experienced headaches, 40% reported blurred vision and 31% had vomiting. About 1% developed severe complications such as meningitis or encephalitis. Peripheral neuropathy and stroke were rare.
The Complication That Shows Up Late
The finding with the most practical relevance for survivors is pituitary damage, which is associated with HFRS.
Injury to the pituitary gland can disrupt hormone production in ways that do not surface until weeks or months after the acute infection has resolved. The review describes resulting problems including fatigue, adrenal insufficiency, the rare disorder diabetes insipidus, sexual dysfunction, absence of menstrual periods in women of reproductive age, and symptoms of low thyroid function.
In one study of hospitalized patients with Puumala infection, most developed neurologic symptoms, almost half had abnormalities in their cerebrospinal fluid, and two experienced sudden vision loss caused by pituitary apoplexy, meaning sudden bleeding or loss of blood supply to the gland.
Long-term consequences have not been well studied. One follow-up found that 20 years after infection, 78% of Puumala patients had persistent high blood pressure and 8% had chronic kidney disease. Whether those outcomes are attributable to the infection itself cannot be determined from that kind of observation.
The practical point for a survivor or a caregiver is that fatigue, hormonal changes or vision problems appearing after apparent recovery are worth raising with a clinician rather than dismissing as a slow convalescence.
What Has Changed Since Our Earlier Coverage
MedicalDaily previously reported that the CDC ended its hantavirus response after all 18 Americans from the cruise ship returned home, and separately examined the 42-day monitoring process that produced zero U.S. illnesses.
Those reports were about containment. The reader question was whether the virus would spread in the United States. It did not.
This report answers a different question: what happens to people who actually get sick, including after they leave the hospital. That shift matters most for the survivors of the Hondius outbreak and their clinicians, and for physicians anywhere who may encounter a returning traveler with rodent or hantavirus exposure.
Nothing in the review changes the containment assessment or suggests new risk to the U.S. general public.
What Remains Unknown
The review is candid about the weakness of the underlying evidence. Most of what is known about hantavirus neurologic disease comes from case reports and small studies, and Nath writes that "the literature is biased toward description of severe and unusual manifestations."
He adds that infections often occur in rural settings with limited resources, which likely means cases are underreported in published literature. The result is a body of evidence skewed toward the dramatic and away from the typical.
There is also no approved treatment. There are no FDA-approved antivirals and no licensed vaccines for hantavirus infection, though some vaccines are in preclinical trials. Several antiviral drugs, including favipiravir, molnupiravir, griffithsin and ribavirin, have shown early promise, but the evidence is not sufficient to change care.
Nath calls for prospective studies with long-term follow-up, which is the only way to establish how often neurologic effects occur and how long they last.
What Readers Should Do Now
For the overwhelming majority of Americans, hantavirus risk is low and comes from rodent exposure, not travel. Prevention is the practical lever: sealing entry points, storing food securely, and avoiding sweeping or vacuuming rodent droppings, which can aerosolize particles. Wetting the area with disinfectant before cleaning and wearing gloves is the standard recommendation.
Anyone who develops fever, muscle aches and worsening shortness of breath after known rodent exposure should seek medical care and tell the clinician about the exposure. The window between recognizable illness and severe disease can be short.
People who survived hantavirus infection, including passengers from the Hondius outbreak, have a more specific takeaway. Persistent fatigue, menstrual changes, vision problems or symptoms suggesting hormone deficiency are worth an evaluation rather than a wait-and-see approach.
Nath also raises a point that falls outside clinical medicine, writing that physicians should work to "prevent the stigma directed toward patients and contacts" while still communicating why isolation matters during an outbreak.
Developing Story Timeline
July 2026: A review in JAMA Neurology synthesizes published evidence on neurologic and pituitary complications of hantavirus infection.
June 2026: The CDC concludes its hantavirus response after all monitored Americans complete their observation periods without illness.
May 2026: The World Health Organization is notified of a cluster of severe respiratory illness aboard the MV Hondius, later confirmed as Andes virus.
April 2026: The MV Hondius departs Argentina on the voyage during which the outbreak occurred.
Frequently Asked Questions
What is new in this review? It is a synthesis of published literature on brain and nerve complications of hantavirus infection, an aspect of the disease that has received less attention than its effects on the lungs.
How common are neurologic complications? Uncommon. In one review of 811 patients with the Puumala strain, about 1% developed severe complications such as meningitis or encephalitis, though headaches were reported by 97%.
What is pituitary damage and why does it matter? Injury to the pituitary gland can disrupt hormone production. The resulting problems, including fatigue, adrenal insufficiency and menstrual changes, may not appear until weeks or months after the acute illness.
Does this change the risk to Americans? No. The review does not alter risk assessments. U.S. hantavirus risk remains low and is primarily tied to rodent exposure.
Is there a treatment or vaccine? No FDA-approved antiviral treatments or licensed vaccines exist. Several antivirals have shown early promise and some vaccines are in preclinical trials.
How do people avoid hantavirus? Seal rodent entry points, store food securely, and avoid sweeping or vacuuming droppings. Wet contaminated areas with disinfectant and wear gloves before cleaning.
When should someone seek care? Fever, muscle aches and worsening shortness of breath after rodent exposure warrant prompt medical attention, and the exposure history should be shared with the clinician.
