#17,447
Not quite two years ago (June 2021) Taiwan reported their first swine variant (H1N2v) infection (see Taiwan CDC Reports Human Infection With Swine Variant H1N2v Virus) in a 5-year-old girl.
That report indicated that that 3 of the patient's contacts had `flu-like' symptoms, but they were unable to identify H1N2v in any of them.
Last December the Taiwan CDC Reported A 2nd Case of Swine-Origin H1N2v Infection, this time in a 7-year-old girl with mild influenza who lived in the central region. As with the previous case, among her 6 closest contacts, 2 had reported flu-like symptoms, but H1N2v was not detected in any of them.
Note: We don't know the exact timing of the testing of these contacts, which might have adversely affected the ability to detect a specific subtype. Their CDC states, however, `There is no evidence of human-to-human transmission'.
Today Taiwan's CDC announces a third detection of this swine-variant virus, and while we have a fairly detailed report, there are some ambiguities in the translation. Media reports (here, and here) report the case as being a young girl, while the Google translation of the press release says `teenage boy'.
Going to Microsoft's Bing Translator for a tie breaker, it returns a less than helpful `minor influenza patient aged 10'.
Regardless of the age or gender, the CDC states that 3 close (asymptomatic) close contacts were tested, and none showed signs of infection. Local pigs tested negative as well. As with the two previous cases, Taiwan's CDC is calling this a `a sporadic case', with no indication of human-to-human transmission.
First the (Google translated) statement from Taiwan's CDC, after which I'll have more on the recent rise in H1N2v around the globe.(Note: Even this translations refers to the case first as a `teenage boy' and then as `the woman'. Take these details with a large grain of salt.).
The third case of H1N2v influenza virus isolated from a patient with respiratory diseases in China has been recovered. The CDC calls on the public to manage their personal health
Release date: 2023-05-11
The Centers for Disease Control and Prevention announced today (11) that a type A influenza virus that could not be subtyped was isolated from a respiratory sample of a teenage boy with mild influenza who lived in central China. After further testing and gene sequencing by the agency It is an H1N2v influenza virus, which is similar to the genetic composition of the first case of H1N2v infection in my country in 2021. Three close contacts of the case were investigated, all of whom had no flu-like symptoms, and no H1N2v influenza virus infection was found after testing. The CDC also invited agricultural authorities and relevant medical experts to hold a meeting to discuss. According to the existing epidemiological investigation results, this case should be a sporadic case, which is similar to past international cases. There is no evidence of human-to-human transmission, and the health and agricultural authorities will continue to Strengthen monitoring of humans, animals and the environment.
The Centers for Disease Control and Prevention pointed out that this case is the third case of H1N2v influenza virus in my country. The case has no recent travel history abroad, and has a history of contact with pigs after the epidemic investigation. On March 13 today (2023), symptoms such as fever, nasal congestion, and muscle pain occurred. He went to the clinic the next day for medical treatment, and the rapid influenza test was positive for type A. The doctor took a test and prescribed influenza antiviral medicine and returned home. He has recovered.
The Centers for Disease Control and Prevention further pointed out that the influenza virus was isolated from the respiratory specimen of the woman on March 28 after being cultured, and other common viruses in respiratory infections such as adenovirus, respiratory fusion virus, enterovirus, and rhinovirus were identified and tested negative. In addition, the agricultural administration unit also collected specimens from pigs in pig farms where the cases had come into contact, and the results showed that no H1N2 influenza virus was detected. In response to the third confirmed case in my country, the CDC will simultaneously notify the World Health Organization through the IHR contact window.
The Department of Disease Control and Prevention stated that the first and second cases of H1N2v influenza virus in my country were detected in April of the previous (2021) and October of last (2022). Engaged in livestock breeding, but the first two cases and this case do not live in the same county and city, and the location of the farm, the source of feed and pigs, and the path of the transport vehicle in the three cases are all different, so the three cases are judged to be unrelated.
H1N2v is a low-pathogenic influenza virus that exists in pigs, and there are occasional cases of human infection reported, and most of them are mild. Since 2011, there have been at least 47 confirmed cases of H1N2v influenza in the world, with 41 cases in the Americas. Some cases have a history of contact with pigs or exposure to contaminated environments, and there is no case of infection through eating meat. The gene sequence of the virus isolated from the patient this time is similar to the H1N2 virus strain isolated from pigs in the past, but not the same. It is sensitive to the current public-funded influenza antiviral drugs.
The CDC reminds that to prevent the new type A influenza, the public should abide by the "5 Dos and 6 Don'ts" principle. and contact history, those who have long-term contact with poultry and livestock should be vaccinated against influenza, have a balanced diet and exercise properly; "6 don'ts": do not eat raw poultry eggs or products, do not smuggle or buy meat from unknown sources, do not touch or feed Livestock, do not release or discard livestock at will, do not mix livestock with other livestock, and do not go to places with poor air circulation or crowded places. For relevant information, please visit the global information website of the CDC (https://www.cdc.gov.tw/), or call the free epidemic prevention hotline 1922 (or 0800-001922).
Prior to 2017, the H1N2v strain of swine flu was only rarely reported, with H3N2v far outpacing it. Since 2017, H1N2v has become far more common, with numerous cases reported in the United States, along with scattered cases reported from Canada, Brazil, Taiwan and France.
Most, but not all of these cases, had plausible contact with pigs.
Last year our own CDC reported 5 H1N2v cases (Georgia, Michigan, Ohio, Oregon, Wisconsin), most of which were connected to attendance of agricultural fairs or the raising of pigs.
Although it is rare to see swine variant viruses spread efficiently in humans, and most cases are mild or moderate, the CDC's IRAT (Influenza Risk Assessment Tool) lists 3 North American swine viruses as having at least some pandemic potential (2 added in 2019).
H1N2 variant [A/California/62/2018] Jul 2019 5.8 5.7 ModerateH3N2 variant [A/Ohio/13/2017] Jul 2019 6.6 5.8 Moderate
H3N2 variant [A/Indiana/08/2011] Dec 2012 6.0 4.5 Moderate
And while we don't a lot of information about it, the CDC currently ranks a Chinese Swine-variant EA H1N1 `G4' as having the highest pandemic potential of any flu virus on their list.
The pandemic risk from swine variant viruses is low, but not zero, as these viruses continue to reinvent themselves as they circulate in pigs.
Although most years we only see a handful of swine variant cases, the reality is most people who get mild or moderate flu are not tested, meaning that these types of infections are probably far more common than we realize.
With the summer agricultural fair season about to kick off, the CDC advises those who are at higher risk of serious flu complications (including children under 5, adults over 65, pregnant women, and those with certain chronic medical conditions), to avoid pigs and the swine barn altogether.
