Health officials in Michigan and Wisconsin are reporting the first cases of H3N2 influenza infections in their respective states.
Since July 2012, the Centers for Disease Control and Prevention (CDC) has reported more than 150 cases of human infections with H3N2v influenza in Indiana, Ohio, Illinois and Hawaii. These human infections have all occurred in persons exposed to, or in proximity to, pigs.
This week, the Wisconsin State Laboratory of Hygiene confirmed two cases of the variant H3N2 (H3N2v) influenza virus in Wisconsin. Test results indicate one of the infections occurred in an adult from southeastern Wisconsin who worked at the Wisconsin State Fair. The individual did not report direct contact with swine.
A second H3N2v infection has been detected in an adolescent who was a swine exhibitor at the Wisconsin State Fair and lives in western Wisconsin. The individuals in Wisconsin are recovering from their illnesses and have not been hospitalized.
In Michigan, a Washtenaw County child has tested positive for the influenza. The child, who had recent exposure to swine at the Ingham County Fair, experienced mild illness and was not hospitalized.
When an influenza virus that normally circulates in swine is detected in a person, it is called a variant influenza virus. Influenza viruses such as H3N2 and its variants are not unusual in swine and can be directly transmitted from swine to people and from people to swine.
When humans are in close proximity to live infected swine, such as in barns and livestock exhibits at fairs, movement of these viruses can occur back and forth between humans and animals.
Influenza has not been shown to be transmitted by eating properly handled and prepared pork or other products derived from pigs.
Although no human-to-human transmission of H3N2v has been documented this year, it is possible that such spread may be shown in the future.
"While this strain of flu is new to Michigan, it's important that people remember the common-sense, simple steps that can be taken to protect their health as we would with any flu season," said Dr. Dean Sienko, interim chief medical executive of the Michigan Department of Community Health. "Washing your hands, covering your nose and mouth when you sneeze or cough, and staying home when you feel sick are some of the best ways to protect yourself and others from becoming ill."
"We encourage people to enjoy all their local fairs have to offer this summer, but to take precautions to reduce the chances of getting H3N2v influenza," said Dr. Henry Anderson, Wisconsin health officer. "As with all influenza viruses, certain individuals can become very ill. Older adults, pregnant women, young children, and people with weakened immune systems should be extra careful and avoid exposure to swine barns this season."
Case investigations have indicated that the illnesses resulting from H3N2v infection have been similar to seasonal influenza. Symptoms include fever, lethargy, lack of appetite and coughing. Some people also have reported runny nose, sore throat, eye irritation, nausea, vomiting and diarrhea. Most cases have resolved on their own and have not required treatment.
Contact your health care provider if you are experiencing flu symptoms and inform the doctor if you have had contact with swine.
To reduce the spread of influenza viruses between pigs and people, CDC recommends these precautions:
- Wash your hands often with soap and running water before and after exposure to pigs. If soap and water are not available, use an alcohol-based hand rub.
- Never eat, drink or put things in your mouth in pig areas, and don't take food or drink into pig areas.
- Never take toys, pacifiers, spill-proof cups, baby bottles, strollers or similar items into pig areas.
- Avoid close contact with pigs that look or act ill.
- Children younger than 5 years, people 65 years and older, pregnant women, and people with certain chronic medical conditions (like asthma, diabetes, heart disease, weakened immune systems, and neurological or neurodevelopmental conditions) are at high risk from serious complications if they get influenza. These people should consider avoiding exposure to pigs and swine barns this fair season, especially if sick pigs have been identified.
For more information about the H3N2v influenza virus and current investigation, visit CDC's website: www.cdc.gov/flu/swineflu/influenza-variant-viruses-h3n2v.htm