Hantavirus: How to Prevent This Rodent-Transmitted Disease

September 29, 2017

According to the Centers for Disease Control and Prevention (CDC), rats and mice worldwide spread over 35 different diseases that can impact humans. (1) Rodents often transmit these infections and diseases to people when someone unknowingly comes into contact with rodent feces, urine or saliva, or more rarely, if they are bitten.

The single greatest risk factor for acquiring the rodent-transmitted virus called hantavirus is having rodent infestation in and around your home. You might not suspect that you’re at risk for hantavirus or other types of rodent-transmitted diseases. But studies have found that many people who wind up becoming infected weren’t aware of their contact with rodents or their droppings until it was too late.

In people who are mostly healthy, hantavirus typically does not cause any severe or long-lasting effects. But in people with compromised immune systems, this, unfortunately, isn’t always the case. Seeking treatment right away if you’re experiencing symptoms of hantavirus is crucial since hantavirus can cause complications when it remains untreated. Early signs and symptoms can include trouble breathing, muscle aches and symptoms associated with a fever. If the virus continues to worsen, it can progress into the life-threatening condition called hantavirus pulmonary syndrome (HPS). (2)

Preventing hantavirus is critical, considering there is currently no specific treatment available that helps a high percentage of patients who have the virus. There is no known cure or vaccine. The CDC states that “Rodent control in and around the home remains the primary strategy for preventing hantavirus infection.” (3)

What Is Hantavirus?

Hantaviruses belong to the Bunyaviridae family. They are carried by rodents and shrews, especially in brown rats found throughout the world. There are a number of strains of hantaviruses that are transmitted from several species of rodents located in different parts of the world, especially cities located along the coasts in the United States, parts of Canada, Asia and Mexico.

Researchers refer to hantavirus strains as either “New World” hantaviruses or “Old World.” Old World hantaviruses are mostly transmitted from rodents living in Europe and Asia. New World hantaviruses are mostly found in rodents living in the Americas.

Different types of hantavirus strains are associated with distinct diseases and symptoms. There have been at least seven types of pathogenic Old World hantaviruses identified that have caused illnesses in humans and one primary type of New World hantavirus.
Hantaviruses include serotypes: Sin Nombre, Hantaan (HTN), Seoul (SEO), Puumala (PUU), and Dobrava (DOB) virus. (4)
The type called Sin Nombre hantavirus was first recognized in 1993. It’s one of several New World hantaviruses that has caused infections in the United States.
The type called Seoul virus is an Old World type that continues to cause infections across the world, including in urban areas. A 2014 report published in the American Journal of Tropical Medicine and Hygiene states that the Seoul virus was previously called the Tchoupitoulas virus. And it has been causing illnesses in the Southern U.S., especially near New Orleans, since at least the 1980s. (5) In 2014 when researchers captured 178 rodents to test them for the Seoul virus, around 3 percent of the animals tested positive.

How common are hantavirus infections?

Generally speaking, rodent-transmitted viruses are believed to be rare. But experts still say that “The degree to which Old World hantaviruses present a threat to public health in the United States remains murky and probably varies considerably by city and region.”

Signs & Symptoms of Hantavirus

Many people who acquire New World hantaviruses are able to recover completely without experiencing any long-term complications or symptoms of chronic infection. The amount of time it takes to recover depends on how healthy the person is, especially the strength of their immune system. Some people with compromised immune systems might take longer to recover or not be able to overcome the virus completely.

Symptoms of hantaviruses can include:

Infection of the lungs, trouble breathing and respiratory distress.
Fever, weakness, muscle aches, nausea, vomiting and chills.
Symptoms that are attributed to hemorrhagic fever renal syndrome (HFRS). HFRS is also sometimes called Korean hemorrhagic fever, epidemic hemorrhagic fever, and nephropathis epidemica. Symptoms of HFRS include intense headaches, back and abdominal pain, fever, blurred vision, flushing of the face, inflammation or redness of the eyes, or a rash.
Some people with HFRS also experience low blood pressure, acute shock, vascular leakage, and acute kidney failure. Seoul virus infections typically result in a milder form of HFRS and don’t often cause hemorrhaging or very serious symptoms.

Complications Due to Hantavirus Infection:

When someone becomes severely affected by an Old World hantavirus, they can develop a very serious condition called Hantavirus Pulmonary Syndrome (HPS). HPS is a respiratory infection that makes it hard to breathe and is sometimes fatal. It initially causes flu-like symptoms, then progresses within 4–10 days to cause “respiratory distress” and symptoms such as: (6)

A strong cough that produces mucus/secretions
Shortness of breath
The lungs filling with fluid
Cardiovascular problems including low blood pressure and reduced heart efficiency

It’s been found that up to 30–50 percent of people who develop HPS don’t survive. Hemorrhagic fever with renal syndrome (HFRS) is less serious. It causes death in about 1–15 percent of infected patients, depending on the specific strain of the virus.

Causes & Risk Factors of Hantavirus

People with hantavirus become infected after they come in contact with hantavirus-infected rodents, their infected urine and/or their droppings. The virus is passed through aerosolized urine or exposure to dust from the nests of infected rodents. Infected urine or other materials can make their way into broken skin or onto the mucous membranes of the eyes, nose or mouth. What types of rodents in the U.S. and elsewhere are capable of carrying the hantavirus? These include the following rodent species: (7)

Cotton Rat (Sigmodon hispidus) — These transmit the type of hantavirus called Black Creek Canal virus (BCCV). They are found in the Southeastern U.S. (from about West Virginia down to Florida, and westward expanding to Texas), Central and South America. The rats have longer fur than most other types that is coarse, grayish-brown, or grayish-black. Tends to live in overgrown areas with shrubs and tall grasses.
Deer Mouse (Peromyscus maniculatus) — Carries the hantavirus strain called Sin Nombre virus (SNV). Found throughout North America (from Mexico through most of the United States and also in Canada), especially in woodlands and deserts. Has big eyes and ears and gray to reddish-brown fur with a white underbelly and tail.
Rice Rat (Oryzomys palustris) — Carries the hantavirus strain called Bayou virus (BAYV). Found in the southeastern U.S. and Central America (from about New Jersey south to Florida and westward to Texas), especially in wet, marshy areas. Has short, soft, grayish-brown fur on top, with white feet and a gray underbelly.
White-Footed Mouse (Peromyscus leucopus) — Carries the hantavirus strain called New York virus (NYV). Found throughout most of the U.S. (especially southern New England and the Mid-Atlantic and Southern states) and also in Mexico. Has a tail is that is shorter than the body, reddish-brown fur, and white feet.

Rodents that carry hantaviruses are found in almost all cities in the world, especially those that are crowded, polluted, have high populations and are close to the water (port cities) which increases the risk for rodent infestation. Experts believe that some of the cities in the U.S. with the most infected rodents include:

New Orleans, Louisiana and other cities located at the Mississippi River outlet to the Gulf of Mexico.
Baltimore, Maryland
Houston, Texas
Philadelphia, Pennsylvania
Cincinnati, Ohio
Columbus, Ohio
Los Angeles, California
New York, New York
San Francisco, California
Seattle, Washington
Tacoma, Washington
Hilo, Hawaii
Other less populated areas in the U.S. including in North Carolina, Maryland, West Virginia, Minnesota, California, Alaska and Mississippi (especially those along the coast).
Globally, in parts of Scandinavia, Western Europe, western Russia, and eastern Asia, particularly cities in China and Korea.

Can hantavirus be transmitted from one person to another (in other words, is hantavirus contagious)?

Evidence shows that humans likely don’t transmit hantavirus to other humans. It only passes from rodents to humans. To date, the CDC states that within the U.S. there haven’t been any cases of of hantavirus reported that have been acquired from contact with another person who was infected. In hospitals where nurses and doctors work with patients who are infected with hantavirus, there have been no reports of the workers developing the illness or symptoms themselves.

There are some rodent-transmitted diseases that can affect humans indirectly, which spread from things like ticks, mites or fleas that are carrying the virus. But evidence shows this doesn’t seem to be the case with hantavirus. It’s also possible that an infected rat carrying the virus might bite other animals like cats, dogs, pigs, cattle, and deer. But no cases in humans associated with contact with other animals have yet to be reported.

Conventional Treatments for Hantavirus

Unfortunately, there is no treatment available at this time to help someone overcome hantavirus infection. One of the reasons scientists haven’t been able to develop a vaccine or treatment for hantavirus is because each time the virus is transferred from its original host to another host, it adapts to its new environment. It mutates and changes form as it makes its way into the host’s RNA.

If a patient is suspected to be infected with hantavirus, then they should be treated right away, ideally in an intensive care unit at a hospital. Depending on how severe the patient’s symptoms become, they will typically be treated in one or more of the following ways: (8)

Intubated and given oxygen therapy to help them deal with respiratory symptoms and try to prevent complications from occurring.
Management of fluid and electrolyte levels (sodium, potassium, chloride) to prevent dehydration or edema.
Correction of oxygen and blood pressure levels.
Use of intravenous ribavirin, an antiviral drug that may help lower the risk of HFRS complications. Ribavirin is used to help treat many types of viruses, including hepatitis C and others. However it isn’t always effective, causes a number of side effects, and is not well-tolerated by people with a number of existing health problems, including: allergies, autoimmune hepatitis, impaired liver function, kidney disease, sickle cell anemia, or thalassemia major.

3 Hantavirus Prevention Tips

1. Minimize Contact with Rodents & Their Droppings

There are certain steps you can take to eliminate (or at least greatly minimize) contact with rodents and their droppings, especially in places where you spend a lot of time, like your home or workplace. You might not think that you’re coming into close contact with rodents or their droppings very often. But research shows that many people who have acquired hantavirus didn’t suspect they were at risk or exposed to rodents very often before coming ill. Preventing rodent infestation is most important if you live in a high-risk area inhabited by the carrier rodents.

Experts recommend taking some of the following precautions around your home and in other places where you spend time:

Seal up any holes or gaps in walls or your garage. This way rodents and other insects cannot make their way into your home. Small mice can squeeze through a hole in your home or garage that’s only about the size of a nickel. And rats can squeeze through a hole the size of a half dollar!
Some places where you might find small gaps or holes inside/around your home include: under or behind kitchen cabinets, refrigerators, pipes, washing machines, hot water heaters and stoves; around a furnaces or fireplaces; around doors, floor vents and dryer vents; inside attics, basements or crawl spaces; and near laundry rooms.
It’s also a good idea to place rodent traps in and around your home to decrease the risk for infestation. Some find that traps work best when you place a small amount of peanut butter on the bait pan of the trap. Then position the trap next to the wall so it forms a “T” shape. Another option that can help is getting a pet cat, which tends to scare away rodents from entering your home.

2. Keep Your Home & Yard Clean to Prevent Attracting Rodents

Don’t leave food, garbage or scraps around your home, which attract rodents and other animals.
If you’re spending time outside, such as when camping or grilling in your backyard, always clean up any waste and food.
If you do suspect that rodents are making their way into your home, or infesting your yard, then take steps to get rid of them as quickly as possible. Speak with an exterminator who can help you trap rodents in and around the home before the problem gets worse.

3. Strengthen & Support Your Immune System

Having a strong immune system might not fully protect you from acquiring hantavirus. And there are no supplements, herbs or drugs that will be able to fully treat you if you already have a hantavirus infection. But increasing your immunity should help you recover quicker and lower the odds that you’ll develop any serious complications. Here are some ways you can increase protection against hantavirus symptoms or help to manage them if you’re already feeling ill from the virus:

Anti-viral herbs that support the immune system include wormwood, black walnut, oregano essential oil/capsules, garlic, bentonite clay, activated charcoal, and grapefruit seed extracts. How do anti-viral herbs work? They have a number of mechanisms and protective effects. These include: treating infections (typically while causing no or few side effects, unlike antibiotics); boosting the immune system by helping the body to attack viral pathogens; helping the body to combat pathogens that mutate over time; and offering cardiovascular, digestive and anti-inflammatory support during periods of illness.
If you’re dealing with symptoms of a fever, such as nausea or vomiting, try eating bland foods, drinking ginger tea and eating foods that have a high water content to help prevent dehydration. Drinking enough water is also important if you’re experiencing diarrhea and vomiting due to a fever. Foods with a high water content include all sorts of fruits and veggies, especially leafy greens, melon, tomatoes, cucumbers, celery, berries, apples, etc. Foods to replace electrolytes also include bananas, avocado, greens and other non-starchy veggies. This should not replace visiting your doctor or getting professional help for restoring electrolyte levels if needed; rather, think of it as another layer of defense.
If you’re feeling fatigued or weak, get extra sleep to support the body during recovery. Plus hold off on any strenuous exercise until you feel much better.
Certain supplements might also help you to feel better, including: omega-3 fatty acids to reduce inflammation; B vitamins to help prevent fatigue; magnesium to help you sleep and lower muscle aches; and adaptogen herbs like medicinal mushrooms to help you overcome the illness.

Precautions If You Think You’ve Been Infected

Experts warn anyone who has been around rodents and experiences signs or symptoms of hantavirus including fever, deep muscle aches, and severe shortness of breath to get help right away by visiting an emergency room or doctor. When hantavirus infection is suspected, the patient should tell their doctor/health care provider that they been exposed to rodents. This way the doctor can test for rodent-carried disease and provide the right treatment.

Final Thoughts on Hantavirus

Hantaviruses belong to the Bunyaviridae family. They are viruses that passfrom rodents living around the world to humans via droppings, urine and bites.
Prevention of rodent infestation is very important. The single greatest risk factor for acquiring rodent-transmitted viruses, including hantavirus, is having rodents and their droppings in and around your home.
There is no cure or standard treatment for hantavirus symptoms, which can include fever and sometimes severe respiratory problems. But ways to help include securing your home; boosting your immune system with herbs and supplements; and treating symptoms like dehydration, trouble breathing, aches and low blood pressure.