What to know about hantavirus
A recent hantavirus outbreak aboard a luxury cruise ship has caught the attention of the American public, raising several questions about the nature of the disease and its societal presence beyond this particular situation.
To gain a better understanding of hantavirus, we spoke with Dr. Stephen Murphy, director for the Center for Health Security & Response Readiness and the director of the MS in Health Security in the Tulane University Celia Scott Weatherhead School of Public Health and Tropical Medicine.
Murphy, who is also an associate professor in the Department of Environmental Health Sciences, stressed that hantavirus is not a pandemic threat at this time. He also shared that the outbreak aboard the cruise ship has been identified as a strain of hantavirus known as the Andes virus, which is capable of being transmitted person-to-person (i.e., contagious between people).
His full primer is outlined below.
What is hantavirus?
Hantavirus cardiopulmonary syndrome (HCPS), also known as hantavirus pulmonary syndrome (HPS), is a zoonotic, viral respiratory disease caused by hantaviruses. More than 20 viral species have been identified. Mice and other rodents often carry the hantavirus, which was first identified in the Hantan River area in Korea (then called the Hantaan virus).
Human hantavirus infection is primarily acquired through contact with the urine, feces, or saliva of infected rodents. It is a rare but severe disease that can be deadly, so it must be taken seriously. Although uncommon, human-to-human transmission has been reported in previous outbreaks of Andes virus (a specific type of hantavirus spread by rodents in South America). This is the lone exception to the known and established transmission modality experienced with hantaviruses – the Andes strain is the only strain known to have human-to-human transmission.
Symptoms — which can include fever, chills, and muscle aches — usually present between one and eight weeks after exposure. This extended incubation period can create additional challenges to controlling an outbreak.
Early symptoms of the disease include fatigue, fever, and muscle aches, especially in the large muscle groups - thighs, hips, back, and sometimes shoulders. About half of all people infected also experience headaches, dizziness, chills, and abdominal problems such as nausea, vomiting, diarrhea, and abdominal pain. Four to 10 days later, other symptoms may appear, including coughing and shortness of breath, as the lungs fill with fluid.
HPS has a mortality rate of about 35%. Unfortunately, there is no specific treatment for (or vaccine against) hantavirus infection. Early recognition of symptoms and prompt access to care may lead to better outcomes than waiting longer before seeking care.
How serious is the cruise ship outbreak?
To date, there have been three fatalities and a total of eight cases of the Andes virus strain in this outbreak. Many passengers from the ship have now been repatriated to their home countries. In the U.S., 18 total passengers were recently evacuated from the ship, including suspected and confirmed cases, with most transported to the University of Nebraska Medical Center. That facility maintains a one-of-a-kind substantial Biocontainment Unit specifically designed for high-consequence pathogen exposures like the current one and is also one of 13 hospital systems collectively known as Regional Emerging Special Pathogen Treatment Centers (RESPTCs) across the U.S. funded by Administration for Strategic Preparedness and Response.
Passengers who test negative and are symptom-free will return home to self-quarantine and be monitored daily by local health authorities during the 42-day incubation period. Officials in at least six states — Arizona, California, Georgia, New Jersey, Texas, and Virginia — are currently monitoring symptoms and health of seven passengers who previously departed the ship and two others potentially exposed to the virus.
As a reminder, the term “quarantine” refers to a strategy that separates potentially exposed individuals until the full disease incubation period. This reduces the risk to the surrounding general public. These individuals are not yet clinically presenting with an illness. If they do become ill, then the individuals will be isolated in a hospital facility – isolation. It is important to remember these terms and the difference.
Risk remains low to the general public
While precautions are being taken and patients are being treated in high-containment patient care units similar to those referenced and used during multiple historical outbreaks, this risk to the public remains low at the moment.
The Andes strain is far less contagious than other disease-causing pathogens such as influenza, RSV, or the recent COVID-19 pandemic.
The current outbreak is not anticipated to precipitate the start of another pandemic and is not likely to lead to future lockdowns. Based on what we know about the pathogen and the data so far, this is a very complicated outbreak, but it poses a low risk to the general public.
Previous Andes virus outbreaks have been successfully stopped through implementing standard contact and droplet precautions - common protocols and steps that are not new or foreign to providers, as we use them annually for things like influenza (i.e., the flu). Further, scientists confirmed that samples from passengers aboard the cruise ship were nearly identical to samples from previous Andes outbreaks, so, thankfully, this current virus is behaving as scientists and providers expect.
What makes this situation even more unique is the environment – unlike foodborne illnesses or perhaps norovirus outbreaks, hantavirus outbreaks have never occurred on cruise ships or maritime vessels. It should be noted that the cruise ship originally departed from Argentina, where the Andes virus is known to be endemic. The first two people to pass away from the virus had traveled in Argentina before the cruise, suggesting that one or both may have been exposed prior to boarding the ship. Additional contact, exposure, and spread among the cruise passengers remain unclear.
Has hantavirus previously been identified in the US?
Hantavirus cardiopulmonary syndrome (HCPS), also known as hantavirus pulmonary syndrome (HPS), is a zoonotic, viral respiratory disease caused by hantaviruses. More than 20 viral species have been identified. Mice and other rodents often carry the hantavirus, which was first identified in the Hantan River area in Korea (then called the Hantaan virus).
The Sin Nombre virus is the predominant cause of HPS in North America. Hantavirus was first recognized in the United States in 1993 as the causative pathogen behind a mysterious respiratory disease that struck the Four Corners region of the southwestern United States. This new pathogen was officially named Sin Nombre virus, which means “virus with no name.” Although rare, with fewer than 800 cases now nationwide since first being identified in 1993, the disease is potentially deadly, especially if it involves the kidneys, heart, or lungs.
Prior to this outbreak, hantavirus was most recently in the U.S. news last year after it was determined that Gene Hackman’s wife, Betsy Arakawa, died from HPS. This species is not the same type driving the outbreak today.
The specific rodent species known to carry the Andes strain of hantavirus has not been seen in the United States.
How do you avoid hantavirus?
Generally, humans contract the disease by coming into contact with infected rodents or their saliva, urine, or droppings. Exposure typically occurs during activities such as cleaning buildings with rodent infestations, as fine particulates from these droppings become aerosolized and “dusted up” into the air one breathes, though it may also occur during routine activities in heavily infested areas. Human cases are most commonly reported in rural settings, such as forests, fields, and farms, where rodents are present, and opportunities for exposure are greater.
To minimize exposure risks, people should limit or avoid altogether contact with rodents and their droppings by storing food securely, sealing possible entry points, and safely controlling infestations. When cleaning potentially affected areas, surfaces should be disinfected first (when possible), and protective gear such as gloves and an N95 mask should be used for respiratory protection.
