By Leanna Coy, FNP, BC
International attention has focused on a Dutch cruise ship, the MV Hondius, after reports of three passenger deaths came out last week. An outbreak caused by a hantavirus was identified as the cause of the deaths, with an additional seven passengers ill with assumed or confirmed hantavirus. The outbreak cluster is rare for hantavirus and has many worried about the possible spread as passengers begin returning to their home countries.
What is the Hantavirus?
Hantaviruses are a group of viruses spread by rodents like mice or rats. In North America, the deer mouse is the most common carrier. People exposed to areas contaminated with infected rodent droppings, urine, or saliva can develop symptoms about a week after exposure, though onset can take up to eight weeks. The main risk is for people who work, clean, or spend time in these contaminated environments.
There are two types of illness or syndromes caused by hantavirus. The flu-like symptoms early in the infection may be mistaken for the flu. Both syndromes can cause life-threatening health problems.
Hantavirus pulmonary syndrome (HPS) is a severe lung disease. The deer mouse spreads the most common hantavirus that causes HPS. About 38% of people who develop respiratory symptoms die from the disease. Early signs of this illness include:
- Fatigue
- Fever, chills
- Body aches, especially in the back, hips, thighs, and shoulders
- Headaches
- Nausea, vomiting, and diarrhea
After the initial illness, symptoms can worsen and progress rapidly. A person can have difficulty breathing, coughing, and chest tightness. These are signs that the lungs are filling with fluid.
Hemorrhagic fever with renal syndrome (HFRS) is an illness that affects the kidneys. This form of the virus is more common in other parts of the world, and different strains vary in severity. In the most severe cases, approximately 5-15% are fatal. Symptoms can begin suddenly with:
- Intense headaches or blurred vision
- Fever, chills
- Nausea, abdominal pain
- Back pain
- Flushing of face, rash
If symptoms worsen, someone may have low blood pressure, internal bleeding, kidney failure with fluid overload, and a lack of blood flow. The strains of viruses that cause this type of infection are found in Europe and Asia.
In North, Central, and South America, HPS is more likely to occur due to the strain of hantavirus in those areas. The Andes virus, which the cruise ship passengers were exposed to, is part of the family of viruses that cause HPS. It is the only hantavirus that is known to spread person-to-person. For this virus to spread, the infected person must have close contact with another person. Close contact means direct physical contact, exposure to body fluids, or spending prolonged time in a close or enclosed space.
Hantavirus risks in Oregon
Since 1993, there have only been 31 cases of HPS documented in Oregon, with 5 deaths reported. The majority of those who became ill had direct contact with mice droppings. The cases included exposure while camping, farming, and at work. Only four cases had no known contact or potential known source. Exposures were found in 14 counties across the state, in both rural and urban areas. No cases were from Tillamook County.
How to prevent infection
If you are working or cleaning areas with mouse droppings, wear a mask and gloves. Consider soaking areas with a disinfectant before cleaning. Try to avoid stirring up dust in rodent-prone areas, such as sheds, cabins, and outbuildings. In infected areas, the virus can become airborne through the dust. Seal up any gaps, holes, or potential entry points in your home, garage, or outbuildings. Always wash your hands after cleaning up rodent urine or droppings.
Hantavirus is found worldwide, but it is uncommon in Oregon. It is rare for clusters of outbreaks to occur, as seen with the outbreak on the Dutch cruise ship. For comparison, the transmission rate of Andes hantavirus is lower than that of COVID-19 because it requires close contact. The World Health Organization and the countries the passengers are returning to are monitoring all those aboard the MV Hondius. Given the nature of hantavirus and the close monitoring by health organizations, it is very unlikely that these infections will lead to a pandemic.
If you are exposed to a hantavirus in Oregon, your risk of spreading it to others is low. You should stay mindful of any flu-like symptoms you develop and seek care immediately for testing and treatment. Make sure you inform your healthcare provider of your contact with any rodent droppings. By taking precautions before cleaning or working in mouse-infected areas, you can keep your risk of infection low.