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Multi-state Outbreak of Seoul Virus

Updated: March 14, 2017

Highlights

CDC is assisting health officials in 15 states in investigating an outbreak of Seoul virus infection that has recently infected 17 people in 7 states. Follow-up investigations by CDC and partnering state and local health departments indicate that potentially infected rodents may have been distributed or received in Colorado, Delaware, Georgia, Illinois, Idaho, Iowa, Minnesota, Missouri, New Jersey, Pennsylvania, South Carolina, Tennessee, Utah, and Wisconsin.

The investigation is ongoing and testing of rats and humans remains a priority. In addition to testing provided by CDC for rats and people linked to ratteries with confirmed infections, commercial testing for rats is also available. In an initial evaluation, the test kits developed by the commercial laboratory IDEXX* yielded test results with similar accuracy to those of the CDC test.

As part of a health monitoring program, rat owners and breeders may wish to seek proof of a rat’s infection status prior to admitting new animals into existing colonies.

Canadian health authorities are investigating Seoul-infected facilities in Ontario with epidemiological links to US rat facilities.

* Names of commercial companies are provided for information purposes only and do not constitute an endorsement by CDC or the Department of Health and Human Services.

Investigation Updates

February 6, 2017

CDC continues to work with Illinois, Wisconsin, and with the potentially affected states, to investigate an outbreak of Seoul virus infections among ten people in Illinois, Wisconsin, who were exposed to infected rats in several rat-breeding facilities in those three states. No additional infections in people have been reported.

As of February 6th, the following states have been notified that that their residents may have infected rats:

  • Alabama
  • Arkansas
  • Colorado
  • Illinois
  • Indiana
  • Louisiana
  • Michigan
  • Minnesota
  • Missouri
  • Iowa
  • South Carolina
  • Tennessee
  • Utah
  • Wisconsin

CDC is working with state health authorities to try to locate the rats and any people who may have been exposed to them in these states and test both people and rats for Seoul virus.

CDC’s current recommendations are:

1. CDC currently recommends blood testing for all people who report recent or current illness after:

  1. handling rats from a facility with laboratory-confirmed Seoul virus infection in either humans or rats, or
  2. handling rats from a facility that sold rats to a facility with Seoul virus infection.

Testing is also offered to persons with exposure to rats from a facility with Seoul virus infection that was confirmed by laboratory testing, or to persons with exposure to rats from a facility that sold rats to a facility with Seoul virus infection but where no illness was reported. All testing should be coordinated with the healthcare provider’s local or state health department.

2. People with potentially infected rats should not sell, trade, or release their rats. They should contact their state health department with any questions. Healthcare providers should emphasize the importance of safe animal practices with their patients.

3. Health care providers may also consider blood testing of patients with symptoms suggestive of Seoul virus infection and a history of rat contact, regardless of whether there is known interaction with rats or rat facilities with laboratory-confirmed Seoul virus infections.

The investigation continues and we will be updating this page as we learn more.

Two CDC epidemiologists arrived in Wisconsin on Jan. 18 to support the response efforts of the Wisconsin Department of Health Services and the Illinois Department of Health. The CDC team will assist with trace-out investigations of clients who purchased rats from, or were otherwise exposed to, the home rat-breeding facilities, and will participate in trace-back investigation of facilities where the patient recently purchased rats. These efforts will help determine how the individuals were exposed to Seoul virus and allow public health officials to take actions needed to prevent potential future spread of the virus. CDC will also assist with testing blood samples from people and rats who may be infected with Seoul virus.

CDC encourages all pet owners and people who come in contact with rodents to practice healthy habits – handwashing, avoiding bites and scratches, providing routine veterinary care – to keep themselves and their pets healthy. See the CDC website Healthy Pets Healthy People.

January 31, 2017

CDC continues to work with Illinois, Wisconsin, and with the potentially affected states, to investigate an outbreak of Seoul virus infections among ten people in Illinois and Wisconsin who were exposed to infected rats in several rat-breeding facilities in those two states. No additional infections in people have been reported.

As of January 31st, the following states have been notified that that their residents may have infected rats:

  • Alabama
  • Arkansas
  • Colorado
  • Illinois
  • Indiana
  • Louisiana
  • Michigan
  • Minnesota
  • Missouri
  • South Carolina
  • Tennessee
  • Utah
  • Wisconsin

CDC is working with state health authorities to try to locate the rats and any people who may have been exposed to them in these states and test both people and rats for Seoul virus.

CDC’s current recommendations are:

1. CDC currently recommends blood testing for all people who report recent or current illness after:

  1. handling rats from a facility with laboratory-confirmed Seoul virus infection in either humans or rats, or
  2. handling rats from a facility that sold rats to a facility with Seoul virus infection.

Testing is also offered to persons with exposure to rats from a facility with Seoul virus infection that was confirmed by laboratory testing, or to persons with exposure to rats from a facility that sold rats to a facility with Seoul virus infection but where no illness was reported. All testing should be coordinated with the healthcare provider’s local or state health department.

2. People with potentially infected rats should not sell, trade, or release their rats. They should contact their state health department with any questions. Healthcare providers should emphasize the importance of safe animal practices with their patients.

3. Health care providers may also consider blood testing of patients with symptoms suggestive of Seoul virus infection and a history of rat contact, regardless of whether there is known interaction with rats or rat facilities with laboratory-confirmed Seoul virus infections.

The investigation continues and we will be updating this page as we learn more.

Two CDC epidemiologists arrived in Wisconsin on Jan. 18 to support the response efforts of the Wisconsin Department of Health Services and the Illinois Department of Health. The CDC team will assist with trace-out investigations of clients who purchased rats from, or were otherwise exposed to, the home rat-breeding facilities, and will participate in trace-back investigation of facilities where the patient recently purchased rats. These efforts will help determine how the individuals were exposed to Seoul virus and allow public health officials to take actions needed to prevent potential future spread of the virus. CDC will also assist with testing blood samples from people and rats who may be infected with Seoul virus.

CDC encourages all pet owners and people who come in contact with rodents to practice healthy habits – handwashing, avoiding bites and scratches, providing routine veterinary care – to keep themselves and their pets healthy. See the CDC website Healthy Pets Healthy People.

January 30, 2017

CDC continues to work with Illinois, Wisconsin, and with the potentially affected states, to investigate an outbreak of Seoul virus infections among eight people in Illinois and Wisconsin who were exposed to infected rats in several rat-breeding facilities in those two states. No additional infections in people have been reported.

As of January 30th, the following states have been notified that that their residents may have infected rats:

  • Alabama
  • Arkansas
  • Colorado
  • Illinois
  • Indiana
  • Louisiana
  • Michigan
  • Minnesota
  • Missouri
  • South Carolina
  • Tennessee
  • Utah
  • Wisconsin

CDC is working with state health authorities to try to locate the rats and any people who may have been exposed to them in these states and test both people and rats for Seoul virus.

CDC’s current recommendations are:

1. CDC currently recommends blood testing for all people who report recent or current illness after:

  1. handling rats from a facility with laboratory-confirmed Seoul virus infection in either humans or rats, or
  2. handling rats from a facility that sold rats to a facility with Seoul virus infection.

Testing is also offered to persons with exposure to rats from a facility with Seoul virus infection that was confirmed by laboratory testing, or to persons with exposure to rats from a facility that sold rats to a facility with Seoul virus infection but where no illness was reported. All testing should be coordinated with the healthcare provider’s local or state health department.

2. People with potentially infected rats should not sell, trade, or release their rats. They should contact their state health department with any questions. Healthcare providers should emphasize the importance of safe animal practices with their patients.

3. Health care providers may also consider blood testing of patients with symptoms suggestive of Seoul virus infection and a history of rat contact, regardless of whether there is known interaction with rats or rat facilities with laboratory-confirmed Seoul virus infections.

The investigation continues and we will be updating this page as we learn more.

Two CDC epidemiologists arrived in Wisconsin on Jan. 18 to support the response efforts of the Wisconsin Department of Health Services and the Illinois Department of Health. The CDC team will assist with trace-out investigations of clients who purchased rats from, or were otherwise exposed to, the home rat-breeding facilities, and will participate in trace-back investigation of facilities where the patient recently purchased rats. These efforts will help determine how the individuals were exposed to Seoul virus and allow public health officials to take actions needed to prevent potential future spread of the virus. CDC will also assist with testing blood samples from people and rats who may be infected with Seoul virus.

CDC encourages all pet owners and people who come in contact with rodents to practice healthy habits – handwashing, avoiding bites and scratches, providing routine veterinary care – to keep themselves and their pets healthy. See the CDC website Healthy Pets Healthy People.

January 27, 2017

CDC continues to work with Illinois, Wisconsin, and with the potentially affected states, to investigate an outbreak of Seoul virus infections among eight people in Illinois and Wisconsin who were exposed to infected rats in several rat-breeding facilities in those two states. No additional infections in people have been reported.

As of January 27th, the following states have been notified that that their residents may have infected rats:

  • Alabama
  • Arkansas
  • Colorado
  • Illinois
  • Indiana
  • Louisiana
  • Michigan
  • Minnesota
  • Missouri
  • South Carolina
  • Tennessee
  • Utah
  • Wisconsin

CDC is working with state health authorities to try to locate the rats and any people who may have been exposed to them in these states and test both people and rats for Seoul virus.

CDC’s current recommendations are:

1. CDC currently recommends blood testing for all people who report recent or current illness after:

  1. handling rats from a facility with laboratory-confirmed Seoul virus infection in either humans or rats, or
  2. handling rats from a facility that sold rats to a facility with Seoul virus infection.

Testing is also offered to persons with exposure to rats from a facility with Seoul virus infection that was confirmed by laboratory testing, or to persons with exposure to rats from a facility that sold rats to a facility with Seoul virus infection but where no illness was reported. All testing should be coordinated with the healthcare provider’s local or state health department.

2. People with potentially infected rats should not sell, trade, or release their rats. They should contact their state health department with any questions. Healthcare providers should emphasize the importance of safe animal practices with their patients.

3. Health care providers may also consider blood testing of patients with symptoms suggestive of Seoul virus infection and a history of rat contact, regardless of whether there is known interaction with rats or rat facilities with laboratory-confirmed Seoul virus infections.

The investigation continues and we will be updating this page as we learn more.

Two CDC epidemiologists arrived in Wisconsin on Jan. 18 to support the response efforts of the Wisconsin Department of Health Services and the Illinois Department of Health. The CDC team will assist with trace-out investigations of clients who purchased rats from, or were otherwise exposed to, the home rat-breeding facilities, and will participate in trace-back investigation of facilities where the patient recently purchased rats. These efforts will help determine how the individuals were exposed to Seoul virus and allow public health officials to take actions needed to prevent potential future spread of the virus. CDC will also assist with testing blood samples from people and rats who may be infected with Seoul virus.

CDC encourages all pet owners and people who come in contact with rodents to practice healthy habits – handwashing, avoiding bites and scratches, providing routine veterinary care – to keep themselves and their pets healthy. See the CDC website Healthy Pets Healthy People.

January 24, 2017

CDC continues to work with Illinois, Wisconsin, and with the potentially affected states, to investigate an outbreak of Seoul virus infections among eight people in Illinois and Wisconsin who were exposed to infected rats in several rat-breeding facilities in those two states. No additional infections in people have been reported.

As of January 24th, the following states have been notified that that their residents may have infected rats:

  • Alabama
  • Arkansas
  • Colorado
  • Illinois
  • Indiana
  • Louisiana
  • Michigan
  • Minnesota
  • South Carolina
  • Tennessee
  • Utah
  • Wisconsin

CDC is working with state health authorities to try to locate the rats and any people who may have been exposed to them in these states and test both people and rats for Seoul virus.

CDC’s current recommendations are:

1. CDC currently recommends blood testing for all people who report recent or current illness after:

  1. handling rats from a facility with laboratory-confirmed Seoul virus infection in either humans or rats, or
  2. handling rats from a facility that sold rats to a facility with Seoul virus infection.

Testing is also offered to persons with exposure to rats from a facility with Seoul virus infection that was confirmed by laboratory testing, or to persons with exposure to rats from a facility that sold rats to a facility with Seoul virus infection but where no illness was reported. All testing should be coordinated with the healthcare provider’s local or state health department.

2. People with potentially infected rats should not sell, trade, or release their rats. They should contact their state health department with any questions. Healthcare providers should emphasize the importance of safe animal practices with their patients.

3. Health care providers may also consider blood testing of patients with symptoms suggestive of Seoul virus infection and a history of rat contact, regardless of whether there is known interaction with rats or rat facilities with laboratory-confirmed Seoul virus infections.

The investigation continues and we will be updating this page as we learn more.

Two CDC epidemiologists arrived in Wisconsin on Jan. 18 to support the response efforts of the Wisconsin Department of Health Services and the Illinois Department of Health. The CDC team will assist with trace-out investigations of clients who purchased rats from, or were otherwise exposed to, the home rat-breeding facilities, and will participate in trace-back investigation of facilities where the patient recently purchased rats. These efforts will help determine how the individuals were exposed to Seoul virus and allow public health officials to take actions needed to prevent potential future spread of the virus. CDC will also assist with testing blood samples from people and rats who may be infected with Seoul virus.

CDC encourages all pet owners and people who come in contact with rodents to practice healthy habits – handwashing, avoiding bites and scratches, providing routine veterinary care – to keep themselves and their pets healthy. See the CDC website Healthy Pets Healthy People.

January 18, 2017

CDC is assisting Illinois and Wisconsin health officials in investigating an outbreak of Seoul virus infection that has infected 8 people in the two states.

The individuals who operated a home-based rat-breeding facility in Wisconsin became ill in December. One was hospitalized. The ill individuals purchased rats from animal suppliers in Wisconsin and Illinois. Trace-backs to two Illinois ratteries revealed six additional people who tested positive for Seoul virus. All individuals have recovered.

Seoul virus is a member of the Hantavirus family of rodent-borne viruses. Seoul virus is carried in the wild by Norway rats. The virus does not make the rats sick but people can become infected through exposure to infectious body fluids (blood, saliva, urine) or bites from infected rats. There is no evidence of human-to-human transmission of Seoul virus. The virus is found in rats throughout the world, but most human infections are recorded in Asia.

Two CDC epidemiologists (one veterinarian and one MD) arrived in Wisconsin on Jan. 18 to support the response efforts of the Wisconsin Department of Health Services and the Illinois Department of Health. The CDC team will assist with trace-out investigations of clients who purchased rats from, or were otherwise exposed to, the home breeding facilities, and will participate in trace-back investigation of facilities where the patient recently purchased rats. These efforts will help determine how the individuals were exposed to Seoul virus and allow public health officials to take actions needed to prevent potential future spread of the virus. CDC will also assist with testing blood samples from people and rats who may be infected with Seoul virus.

CDC encourages all pet owners and people who come in contact with rodents to practice healthy habits – handwashing, avoiding bites and scratches, providing routine veterinary care – to keep themselves and their pets healthy. See the CDC website Healthy Pets Healthy People.

At A Glance

Number of laboratory-confirmed recent human cases of Seoul virus: 17

Number of states reporting laboratory-confirmed Seoul virus positive results for humans or rats: 11: CO, GA, IA, IL, MN, MO, PA, SC, TN, UT, WI

States with facilities (for example, homes or premises) currently under investigation: 15: CO, DE, GA, IL, ID, IA, MI, MN, MO, NJ, PA, SC, TN, UT, WI

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