Taiwan CDC Warns of Travel To United States Due To trH3N2

Recombinomics Commentary 14:00
November 10, 2011
International Travel epidemic

The United States - H3N2 swine flu

Source: WHO Event Information Site for IHR National Focal Point, 2011/11/2

U.S. 11 / 1 reported two cases of swine-derived H3N2 influenza cases, prior to the onset had a history of contact with pigs. 1 case of 8-year-old boy, the incidence of 10/22, 10/24 medical treatment; the other 1 case of 58-year-old male veterinarian, the incidence of 10/20, 10/21-10/24 hospital. The United States this year, total 7 cases swine-derived H3N2 influenza cases so far in 2005 total of 15 cases.

Relevant countries and regions:

The above translation is from the Taiwan CDC website which warns of travel to all 50 US states and District of Columbia due to the two most recent trH3N2 cases described at the WHO password protected site (IHR National Focal Point) for the reporting of diseases covered by International Health Regulations.

As seen above, like the WHO update on pandemic vaccine target, the 15 trH3N2 confirmed cases are reports as beginning in 2005, although the first US case was reported in August. 2009.  Thus, the concentration of cases is far higher than indicated on the WHO website designed for submission and reporting of a variety of cases including those infected by a novel influenza, such as trH3N2.

Although media and ProMED are reporting these cases as “sporadic” jumps from pigs to people, all 7 cases from the US, including the two cases cited above, have the identical constellation of flu genes which has never been reported in swine.

The finding of the 3 or more identical constellation of genes in triple reassortant cases, other than those infected with H1N1pdm09, is without precedent and clearly signals human transmission. Thus far reported 2011 trH3N2 cases have been limited to Indiana, Pennsylvania, and Maine, the 7 cases represent 70% of influenza cases reported by these states since July, 2011.

There has been limited and biased testing in the US, due in part to the CDC request for samples in the early release MMWR describing the first two 2011 cases, which limited samples to cases with a swine exposure.

The CDC should announce a modified request for pediatric samples from cases with flu-like symptoms and/or those that are influenza A positive.  These cases cannot be tested for trH3N2 by state agencies and samples must be tested by the CDC at this time, but an expanded testing of samples without swine exposure, such as the atypical pneumonia cases in Shelby County Indiana, is long overdue.

Asymptomatic Swine Linked To Indiana Veterinarian With trH3N2
Recombinomics Commentary 12:30
November 10, 2011

1 case of 58-year-old male veterinarian, the incidence of 10/20, 10/21-10/24 hospital.

The above translation is from the travel warning issued by the Taiwan CDC regarding trH3N2 in the United States.  The warning sourced the above information to the WHO Event Information Site for IHR National Focal Point dated 11/2.

The above dates and description of the trH3N2 case matched the characterization sheet associated with the sequences released by the US CDC for A/Indiana/10/2011 and subsequently reported by the Indiana State DoH and the US CDC.

Therefore, Recombinomics contacted Dr Bret Marsh, State Veterinarian at the Indiana State Board of Animal Health, who investigated the case.  He noted that all of the swine contacted by the veterinarian prior to symptoms had been asymptomatic for at least a month prior to contact, reducing the likelihood that these swine were the source A/Indiana/10/2011.

Similar results had been reported for the caretaker for the first 2011 trH3N2 case (2M) from Indiana.  The case had no swine contact and the caretaker ,as well as the swine linked to the caretaker, were asymptomatic.

Similarly, the swine presented at the Washington County fair in Pennsylvania were asymptomatic and the disease onset dates for the two Maine cases reduces the likelihood of a swine origin for these case.  The first case (8M) was from Cumberland county and he developed symptoms on October 7 (sample collected October 10).  He attended a agricultural fair in the week prior to symptoms, which was almost certainly the Cumberland County fair, which ended October 2.  The five day gap between the end of the fair and the disease onset dates reduces the likelihood that the swine were at source of A/Indiana/06/2011.  The second case was also exposed to swine at an agricultural fair and since the second case lived in the vicinity of the first, he (also 8M) his “exposure” was also associated with the Cumberland County fair, but he developed symptoms two weeks later (sample collected October 22) significantly reducing the likelihood that the swine at the fair were a source of his infections.  Moreover, there have been no reports of symptomatic swine at the fair in Maine.

The absence of linkage to any symptomatic swine by any of the 7 confirmed cases is consistent with the sequence analysis of the isolates from the human cases, which share the same constellation of genes with each other, including an M gene from H1N1pdm09, which has never been reported in swine anywhere in the world in spite of increased swine surveillance, including SOIV sequences from swine in Indiana and Pennsylvania collected in 2010 and/or 2011.

Moreover, the trH3N2 cases dominate the confirmed cases in the above states.  The two trH3N2 cases in Maine represent the only two reported cases since July 2011.  Similarly, the Indiana cases represent 2 of the 3 influenza cases in Indiana, while the Pennsylvania cases represent 3 of the 5 confirmed influenza cases in Pennsylvania.

Thus, the swine “exposure” is more closely linked to sample collection and testing than transmission from swine, which highlights the need for aggressive testing of cases without swine exposure, such as the atypical pneumonia cases in Shelby County, Indiana.