Sunday, August 05, 2018

California: San Luis Obispo Public Health Investigating Suspected Swine Variant Flu Cases

San Luis Obispo County - Credit Wikipedia


Since 2005, 23 states - mostly from the Mid-West but ranging as far away as Hawaii - have reported human infection with swine variant viruses (H3N2v, H1N1v, or H1N2v).  
Of the 468 known infections, Indiana (n=154) and Ohio (n=137) make up over 60% of the cases.
Until now, California hasn't been on this list, but depending upon the results of pending tests, that status may be about to change.
Like we saw in Michigan last week, and in Indiana in early July, pigs carrying swine flu are suspected of infecting fairgoers at the California Mid-State fair.
First the statement from the San Luis Obispo County Health Department, and then I'll return with more.

Public Health Department Investigates Influenza Cases in Community

Author: Public Health Department
Date: 8/3/2018 6:18:23 PM

The County of San Luis Obispo Public Health Department is investigating several cases of influenza (flu) in the community.

The County of San Luis Obispo Public Health Department is investigating several cases of influenza (flu) in the community to determine whether they are linked to a case of influenza in a pig at the California Mid-State Fair.

At this time, several patients have tested positive for an influenza virus that may be different from viruses that commonly circulate among people during flu season. These people had extended contact with pigs at the Mid-State Fair. At this time, the Public Health Department does not have any laboratory confirmation that the cases are linked to pigs. In each of the laboratory-confirmed local cases of influenza being investigated, patients have recovered on their own within several days.

While the virus in these cases may be different from the viruses that commonly circulate among people during flu season, the symptoms and treatment are the same.

Influenza viruses commonly circulate in pigs. From time to time, one of these viruses can be transmitted from a pig to a human. In these cases, it is referred to as a variant influenza virus infection. This most commonly happens when people have extended close contact with pigs. A number of cases of pigs transmitting influenza to humans at agricultural fairs have occurred in other states in recent years.

When the virus is transmitted from a pig to a person, it generally does not spread widely to other people.

It cannot be transmitted by eating pork.

As a precaution, people who had extended contact with pigs at the Mid-State Fair should be alert for symptoms of the flu: fever, cough, sore throat, muscle or body aches, headaches, and fatigue. Some people may experience vomiting and diarrhea with the flu. Symptoms usually start about one to four days after being exposed and last two to seven days.

If you experience flu symptoms—now or during flu season—it is generally most effective and most comfortable to recover on your own at home.

Some people are especially at risk for serious complications from the flu, including very young children (under age 5), older adults (over age 65), and people with certain underlying medical conditions. These people should be especially alert and, if they experience symptoms of the flu, seek treatment from their regular doctor’s office.

Flu of any sort can be dangerous and even healthy people can sometimes experience serious complications. If you experience difficulty breathing, shortness of breath, chest pain, severe abdominal pain, confusion, sudden dizziness, or severe vomiting that won't stop, seek medical attention immediately.

If you do not experience these symptoms and are not in these high-risk groups but are concerned about flu-like symptoms, call your regular healthcare provider. If you do not have a regular healthcare provider, call or visit your local urgent care center.

If you seek medical attention for the flu and have had extended contact with pigs, tell your health care provider about that contact.

The California Department of Public Health and California Department of Food and Agriculture have been informed of this investigation.

(Continue . . . )
So far, we haven't seen any indication of the influenza subtype in this latest outbreak - only that it is `different' from human seasonal flu.  Presumably we'll get more details from the CDC in the days to come.
Swine flu outbreaks linked to county fairs and agricultural exhibits present a particularly sticky problem for both fair organizers, and public health officials. 
While most swine variant infections have been mild or moderate, and ongoing transmission has been limited, there is always the potential for a new strain to come along that is either more severe - or more easily transmitted in the community - and that could prompt a genuine public health emergency.

But county fairs and agricultural exhibits represent months of work by hundreds or even thousands of people, a huge financial investment, and are highly anticipated by the public. 
Canceling them over what is widely considered a small health risk is difficult to justify. 
Particularly since we've seen outbreaks like these before. In 2012, more than 300 people were infected across 10 states (see CID Journal: H3N2v Outbreaks In United States – 2012), and yet these outbreaks fizzled out.

But, as we saw a year ago in EID Journal: Transmission Of Swine H3N2 To Humans At Agricultural Exhibits - Michigan & Ohio 2016, these venues are particularly good at disseminating novel flu viruses to the public.  

The authors wrote:
Variant influenza infections in humans continue to occur through contact with exhibition swine; often, the cases are in swine exhibitors with close and prolonged swine exposure. The concurrent detection of genetically identical influenza A viruses from exhibition swine across 2 states illustrates the rapidity with which this virus, and potentially other pathogens, can move within the highly mobile exhibition swine population.
In addition to the zoonotic risks of influenza A virus, this pattern serves as a warning of possible dissemination of other emerging or high-consequence diseases in swine.

Management practices common in the exhibition swine industry (i.e., frequent exhibition and relaxed biosecurity) facilitate the rapid dissemination of influenza virus across a large geographic landscape (14).

Of note, while widespread illness in pigs was only rarely reported, surveillance  revealed an average prevalence of influenza A in fair pigs of  77.5%. This study cautions that this suggests `that subclinical influenza A infections in pigs remain a threat to public health (3).' 
For now, the risks to public health are probably small, but that could change should one of these viruses evolve into a more human-adapted virus.
Despite the current low risk of infection, there are some things you should consider doing to reduce your chances of getting sick at the fair, particularly if you are at `high risk' of flu complications.  This from the CDC.

CDC Recommendations For People At High Risk:
  • If you are at high risk of serious flu complications and are going to a fair where pigs will be present, avoid pigs and swine barns at the fair. This includes children younger than 5 years, people 65 years and older, pregnant women, and people with certain long-term health conditions (like asthma, diabetes, heart disease, weakened immune systems, and neurological or neurodevelopmental conditions).
If you are not at high risk, take these precautions:
  • Don’t take food or drink into pig areas; don’t eat, drink or put anything in your mouth in pig areas.
  • Don’t take toys, pacifiers, cups, baby bottles, strollers, or similar items into pig areas.
  • 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.
  • Avoid close contact with pigs that look or act ill.
  • Take protective measures if you must come in contact with pigs that are known or suspected to be sick. This includes wearing personal protective equipment like protective clothing, gloves and masks that cover your mouth and nose when contact is required.
  • To further reduce the risk of infection, minimize contact with pigs in the pig barn and arenas.

No comments: