2 People Infected With Swine Flu in Michigan, CDC Reports

Swine flu viruses can cause high levels of illness in pig herds, but cause few deaths in pigs. Joern Pollex/Getty Images

Two cases of human infections with swine flu viruses have been identified in Michigan, the first such cases in the United States in 2023, the Centers for Disease Control and Prevention (CDC) said Friday.

The CDC said that the two individuals were exposed to pigs while attending different agricultural fairs in Michigan.

The first individual became ill after attending a fair between July 7 and July 16 in the state.

The second person attended the Tuscola County Fair from July 23 and 29, the Tuscola County Health Department said in a press release [pdf]. The patient exhibited flu-like symptoms before testing positive for the virus.

Both patients were given flu antivirals and did not require hospitalization. The CDC stated that there have been no instances of person-to-person transmission of the swine flu virus following these cases so far.

“Every year, there are rare sporadic human infections with flu viruses that usually spread in pigs. When found in people, these are called ‘variant flu virus’ infections and designated with the letter ‘v’ after the subtype,” the CDC said in a press release.

“While infections with swine influenza viruses usually cause mild illness, they are concerning because they can cause severe illness, especially in people at higher risk of serious flu complications, and because of their pandemic potential,” it added.

According to the CDC, pigs can catch flu viruses from birds, human, and their own kind. When flu viruses from different species infect pigs, the viruses can swap genes, but “very rarely” new viruses can emerge and have person-to-person spread.

“This is thought to have happened in 2009 when a new swine-origin H1N1 virus with genes of avian, swine, and human origin emerged to cause a flu pandemic,” it stated.

People were advised to take precautions while visiting fairs by refraining from eating or drinking while in pig areas, avoiding contact with pigs that appear to be sick, and washing hands with soap before and after contact with pigs.

“Infected pigs can cough or sneeze, and droplets with the virus in them can spread through the air. If these droplets land in your nose or mouth or are inhaled, you can be infected,” the CDC explained.

“These infections have most commonly been reported after close proximity to infected pigs, such as in pig barns and livestock exhibits housing pigs at fairs,” it added.

Swine Flu Symptoms

Symptoms of swine flu in humans are similar to those of seasonal flu viruses. They can include fever, respiratory symptoms like cough and runny nose, body aches, nausea, vomiting, and diarrhea.

The CDC estimated that there were about 60.8 million cases of swine flu between 2009 and 2010 in the United States. Among these cases, 274,304 required hospitalizations, and 12,469 others died from the disease.

In March 2021, tens of thousands of pigs were slaughtered in the Dominican Republic after outbreaks of African swine fever were detected in 11 of the country’s 32 provinces.

Reuters contributed to this report.