State and federal health officials say 8 people who breed pet rats have been infected with a rare and potentially deadly virus called Seoul virus. 
The illness is a form of hantavirus, a respiratory infection spread through rat droppings. Eight people in Illinois and Wisconsin have been diagnosed, some of whom required hospital care, according to CDC officials. In a statement, the agency said:
“A home-based rodent breeder in Wisconsin was hospitalized in December 2016 with fever, headache and other symptoms.
CDC tested a blood specimen and confirmed that the infection was caused by Seoul virus, a member of the Hantavirus family of rodent-borne viruses. A close family member who also worked with rodents also tested positive for Seoul virus. Both people have recovered.”
As it turns out, the Wisconsin breeders had purchased the rats from 2 rat-breeding facilities in Illinois. Six more diagnoses followed, all in individuals who worked at the Illinois facilities. 
Hantaviruses were first identified in 1993. In 2012, an outbreak of hantavirus claimed the lives of 3 campers. Health officials were so confused by the first cases that they were dubbed Sin Nombre virus — Spanish for “the virus without a name.” 
The Seoul virus is a milder type of hantavirus that can cause fever, chills, nausea, pink eye-type eye infection and abdominal pain. In rare cases, it can progress to hantavirus pulmonary syndrome, which begins with fever, severe aches and fatigue, and may turn fatal. 
It typically takes 1-2 weeks for symptoms of Seoul virus to appear, but can take as long as 8 weeks to emerge. Of the 8 patients that were infected, only 1 of them experienced symptoms.
The Seoul virus is carried by wild Norway rats worldwide. It is spread via contact with infectious body fluids, including blood, saliva, and urine from infected rats, or a bite from one of the rodents. There have been several cases in the U.S. in the past that were traced back to wild rats. Seoul virus cannot be transmitted from person to person. 
However, the 8 cases are the first cases observed in the U.S. associated with pet rats, though transmission through pets is not unheard of, said Dr. Jennifer McQuiston, a veterinarian and deputy division director for CDC’s division of high consequent pathogens and pathology. She explained:
“There was an outbreak reported in Europe previously associated with pet rats, so it’s not the first time this has been associated with pets worldwide.” 
Avoiding the Seoul Virus
Here’s a few tips for avoiding the Seoul virus:
- Wash your hands after touching or feeding pet rats, or cleaning their cages.
- Make sure pet rats are properly secured (in a cage) so they don’t contaminate surfaces in your home.
- If possible, clean rodent cages and rodent pet supplies outside of your house, and never clean the animals’ cages or supplies in your kitchen or other areas where you prepare food.
- Avoid bites and scratches from rodents.
- Take your pet to a veterinarian for routine care to keep the animal healthy and disease-free. 
 NBC News
 Live Science