Last summer, there were a dozen reported cases of an influenza A variant virus called H3N2v. This strain comes from pigs. As of today, the official CDC count is 145 cases reported, with a big surge seen in July 2012.
The CDC will report the number of confirmed cases every Friday and that number of 145 is expected to increase tomorrow, 10 August, as the CDC gets more reports from the states.
Because the states are now able to confirm cases without waiting for CDC’s confirmation, the states will always have the most current numbers.
This surge is thought primarily to be connected to agricultural fairs being held around the country.
Before 2007, there were one or two cases reported each year. After that time, and until 2010, there were maybe half a dozen cases reported each year due to improved diagnostics provided to the states.
CDC’s Dr. Joseph Bresee of the Influenza Division says that most of those infected have had direct or indirect exposure to infected pigs, although there have been limited numbers of human-to-human transmission.
Over 90 percent of the infected have been children. Children tend to be the ones that care for the pigs at the fairs, and it may be that while adults have had exposure to H3 viruses and that has given them some antibody protection, the children have no such antibodies.
The symptoms are typical of seasonal influenza and the cases so far have been mild, with a total of five individuals hospitalized since July 2011.
- Fever or feeling feverish/chills (not everyone has a fever)
- Sore throat
- Runny or stuffy nose
- Muscle or body aches
- Fatigue (tiredness)
- Some people may have vomiting and diarrhea, though this is more common in children than adults.
There have been no deaths, and those hospitalized have been released and are well. More hospitalizations are expected for those with high risk conditions.
There is no evidence that there is sustained efficient human-to-human transmission, and it’s not a pandemic situation, but the CDC is monitoring the situation.
Large numbers of agricultural fairs are ongoing in the US, and pigs are the primary source of infection, so it’s recommend that those attending such fairs:
- Wash hand frequently before and after exposure to animals
- Don’t eat or drink around animals
- Keep away from sick pigs
- If one is at high risk of seasonal flu, avoid exposure to swine completely when going to fairs
If you have flu symptoms following direct exposure to swine, tell your doctor about that exposure so that antivirals may be considered.
The H3N2v strain is not in the seasonal flu vaccine, but get vaccinated to protect yourself against the other strains of influenza.
Image courtesy of The Portland Press Herald