Important notice: Seoul Virus outbreak in pet rats and humans

  |   One Health, Uncategorized

As of February 22nd, 2017 no human or rodent cases of Seoul hantavirus have been confirmed in Washington State. 

During late December 2016, the Centers for Disease Control and Prevention (CDC) was notified about a patient in Wisconsin who presented to a hospital earlier that month with fever, headaches, leukopenia, transaminitis, and mild proteinuria. Hantavirus infection was suspected because the patient breeds and sells Norway rats (Rattus norvegicus) primarily for pets and to a lesser extent for feeding to carnivores (snakes). Additionally, a family member of the patient presented to a health care facility with fever, eye pain, headache, anorexia, diarrhea and cough, and proteinuria. Both were confirmed with Seoul hantavirus infection by CDC’s Viral Special Pathogens Branch.

Seoul virus is in the hantavirus family, and it produces a milder illness than some other hantaviruses. Symptoms may include fever, severe headache, back and abdominal pain, chills, blurred vision, redness of the eyes, or rash. In rare cases, infection can also lead to an acute renal disease called Hemorrhagic Fever with Renal Syndrome (HFRS). The Norway rat (Rattus norvegicus) and the black rat (Rattus rattus), both wild and domestic, are the natural host for Seoul virus.

Eight states have reported laboratory-confirmed Seoul virus positive results for humans or rats (CO, IL, MN, PA, SC, TN, UT, WI) and ratteries are under investigation in an additional 16 states (AL, CO, GA, IL, IN, IA, LA, MI, MN, MO, ND, PA, SC, TN, UT, WI). Updated information is regularly posted on the CDC website.

Again, as of February 22nd, 2017 no human or rodent cases of Seoul hantavirus have been confirmed in Washington State.

Because live rats pose a risk of Seoul virus transmission to people who come into contact with them, it is important to maintain awareness of the distribution of Seoul virus -infected rats.

Important actions

Surveillance: In order to enhance surveillance for Seoul virus in Washington State and to ensure appropriate follow-up of exposed persons, the Washington State Department of Health (DOH) is requesting that veterinarians report all positive results of testing for Seoul virus in Washington to the state public health veterinarian.

Ask about the origin of rat patients that present to your practice to identify if they might be part of this outbreak. Please contact your local health jurisdiction about rats purchased from states with infected ratteries as detailed on the CDC website.

Biosecurity: when handling Norway rats (especially those of unknown origin), wear personal protective equipment, including protective outerwear, gloves, head and shoe covers and fit-tested N95 respirators.

Testing: Consult your local health jurisdiction to discuss options for testing if an owner requests Seoul virus testing of pet rats.

  • We currently do not recommend routine testing of pet rats unless they are associated with this outbreak.
  • CDC is currently providing testing for rats associated with confirmed ratteries only.
  • If rat owners request testing for rats not associated with an affected facility, serology and PCR is available through commercial veterinary laboratories.
  • The incubation period for adult rats to develop antibodies after exposure is approximately 4 weeks. If it has been less than 4 weeks since the purchase of a rat, animals should be retested again once this period has passed.

Safety: If you develop symptoms consistent with Seoul virus infection (fever, muscle pain, headache, red eyes, rash), contact your healthcare provider and be sure to mention your contact with rats. Safe pet handling and clean-up practices should be emphasized to all pet owners. Visit these websites for more information:

Personal Protective Equipment (PPE) for Veterinary Personnel when handling rats suspected of Seoul virus infection

The National Association of State Public Health Veterinarians has developed a Compendium of    Veterinary Standard Precautions that provides guidance intended to minimize transmission of zoonotic pathogens to veterinary personnel. The current 2015 Compendium is accessed at the National Association for Public Health Veterinarians website or from AVMA.

Seoul virus is a hantavirus that may be transmitted by aerosols. For veterinary procedures involving rats from confirmed facilities, airborne and droplet transmission precautions—as outlined in the Compendium—are recommended. Hand-washing, gloves, face shield or goggles, protective outer garments, and respiratory protection (such as N95 or N99 particulate respirators, or a powered air-purifying respirator [PAPR]) are recommended. In addition, it is recommended that such personal protective equipment be used when handling the bedding or cleaning the cages of rodents suspected of Seoul virus infection.

Contact Information

By Dr. Ron Wohrle, Washington State Department of Health



February 24, 2017