New Rodent Infection Threatening Humans

The Centers for Disease Control and Prevention (CDC) is assisting health officials to manage an outbreak of Seoul Virus that has impacted more than 15 states and infected more than 20 people. This is the first Seoul virus outbreak in the United States and has mainly centered in ratteries that bread rats for pets and industry. Investigations are following up on potentially infected rodents in Colorado, Delaware, Georgia, Illinois, Idaho, Iowa, Minnesota, Missouri, New Jersey, Pennsylvania, South Carolina, Tennessee, Utah, and Wisconsin.

What is Seoul virus?

Seoul virus is a Hantavirus related to the sin nombre Hantavirus responsible for the outbreaks of severe cardiopulmonary syndrome, life-threatening infections in the four corners area of the southwest. 

Seoul virus is not harmful to rats and they do not show symptoms of disease when they are infected, so it is difficult to suspect infection amongst rats. However, once infected, rats can continue to shed virus throughout their lives, potentially infecting other rats and humans. 

How is Seoul Virus transmitted?

The virus is transmitted from infected rats to humans through their bodily fluids, such as urine, droppings, or saliva. People may also become infected when the urine or these other materials containing the virus get directly into a cut or other broken skin or into their eyes, nose, or mouth. In addition, people who work with live rodents can get the Seoul virus through bites from infected animals. It is also possible to become infected through “aerosolization”, which occurs when tiny particles containing the virus become airborne and inhaled by humans (such as when nesting materials or excrement are stirred up by things such as vacuuming or sweeping).

What are the symptoms of Seoul virus?

Seoul virus infection in humans is generally less severe than some other types of Hantavirus infections. Symptoms are usually mild and typically begin within one to two weeks of exposure and include fever, headache, back and abdominal pain, chills, nausea, blurred vision, flushing of the face, inflammation or redness of the eyes, and a rash. Some people may develop a severe form of infection with a type of acute renal disease called Hemorrhagic Fever with Renal Syndrome (HFRS). In these cases symptoms may include low blood pressure, acute shock, and acute kidney failure. An estimated 1-2 percent of people may die after being infected with Seoul virus.

How is Seoul virus diagnosed and treated?

Several laboratory tests of blood and body tissues are used to confirm a diagnosis of Seoul virus infection in patients suspected to have an infection. Both the CDC and commercial assays are available for testing.

Ribavirin, an antiviral drug, has been shown to reduce the illness severity and lower deaths related to Seoul virus infections if used very early in the disease. However, usually by the time Seoul virus infection is suspected the ribavirin treatment window has passed. Therefore, generally, supportive care (such as fluids, oxygen, electrolytes such as sodium, potassium) is given to people infected with Seoul virus. Dialysis may be required in severe cases of kidney failure. 

How can I prevent Seoul virus?

Because there is presently no effective treatment for Seoul virus infection, preventing infections in people is important. Avoiding contact with rats and rodent control are key for preventing Seoul virus infections. Rodents near human communities should be controlled, and rodents should be excluded from homes. You should avoid contact with rodent urine, droppings, saliva and nesting materials.

If you suspect an exposure problem, contact you physician with this concern. If you suspect a rodent infestation, contact a licensed pest professional immediately to treat the problem.