Flu Scan for Jul 23, 2014

News brief

Swine and human H3N2v samples from 2012 closely match

Genetic comparisons between variant H3N2 (H3N2v) influenza viruses collected from swine at Ohio fairs in 2012 and those collected from case-patients from a large outbreak that year showed an almost 100% match, according to a study today in Emerging Infectious Diseases.

Researchers swabbed at least 20 pigs at 40 different Ohio agricultural fairs. They isolated H3N2v from 159 (19%) of 834 pigs sampled. The infected pigs were from 10 fairs, 7 of which were associated with human H3N2v cases that year. The 30 fairs that had not H3N2v in swine did not report any human cases in 2012.

They found that the overall nucleotide identity of 27 swine isolates was greater than 99.5%, and the match between human and swine isolates at five of the seven fairs linked to human cases was greater than 99.9%. Isolates at the other two fairs were 99.74% and 99.87% identical.

The authors say their results indicated that one strain was widely circulating among exhibition swine in Ohio in 2012, and that swine viruses were infecting people rather than the other way around.
Jul 22 Emerg Infect Dis report

Study: H10 viruses bind tightly to human receptor cells

The H10N8 avian flu virus, which has infected three people after appearing in humans for the first time in December 2013, killing two, likely binds well enough to human receptors to explain human cases but not well enough to cause widespread disease, according to a study today in Nature.

UK investigators analyzed data on an H10 avian virus to deduce the properties of H10N8. They used biolayer interferometry to measure binding properties and combined them with data for human and avian H7 viruses, as well as to two pandemic strains—1918 H1N1 and 1968 H3N2.

They write, "The data show, first, that the avian H10 virus binds to human receptors substantially tighter than avian H7 virus and somewhat tighter even than human H7 virus. Second, avian H10 binds avian receptor significantly tighter than either human or avian H7 viruses."

The team also found that H10 binds to human receptors almost as strongly as both pandemic viruses.

They conclude, "Avian H10N8 virus has sufficient avidity for human receptors to account for its infection of humans but that its preference for avian receptors should make avian-receptor-rich human airway mucins an effective block to widespread infection.

"In terms of surveillance, particular attention will be paid to the detection of mutations in the receptor-binding site of the H10 haemagglutinin that decrease its avidity for avian receptor, and could enable it to be more readily transmitted between humans."
Jul 23 Nature letter

Bacterial contamination issues at GSK Canadian flu vaccine plant identified

Canada's only flu vaccine production plant, owned by GSK, has received word from a Health Canada inspection that 10 issues need to be addressed to meet required standards, according to a Canadian Press article today. GSK has until Aug 4 to submit a plan to fix the problems.

Health Canada posted a summary of its inspection findings late yesterday. Some major findings related to two new vaccines being made at the plant that are licensed in Canada but not yet sold there. The regulatory agency said GSK has to give 90 days' notice before resuming production of the vaccines to allow further inspections and action as necessary.

None of the issues raised pose a critical risk to public health, but 7 of the 10 fall into the major observation category, says the story.

The plant has contracts to produce 53% of Canada's seasonal flu vaccine for next season and "also holds a 10-year contract to produce pandemic for vaccine for Canada when needed," the story notes.

It is also scheduled to provide 23 million flu vaccine doses for the United States for 2014-15. The US Food and Drug Administration (FDA) issued a warning letter to the plant Jun 21 saying that 21% of the upcoming season's product had unacceptable bacterial counts and could not be used.

Health Canada inspects the plant, which is in Ste. Foy, Quebec, every 2 years. The plant is reportedly cooperating with both Health Canada and the FDA on resolving the issues, the story said.
Jul 23 Canadian Press story

News Scan for Jul 23, 2014

News brief

CDC: Imported US chikungunya cases surge to 300

The chikungunya epidemic in the Caribbean is continuing to spill over into the United States, with 300 imported cases identified as of yesterday, an increase of 66 from a week earlier, according to the Centers for Disease Control and Prevention (CDC).

Of the 300 cases, 295 were in travelers returning from the Caribbean or South America, the CDC said. The other five were associated with trips to Pacific islands (4 cases) or Asia (1).

Florida has had by far the most cases, 77, followed by New York with 30 and Tennessee with 18. Cases have been reported in 35 states, but most have fewer than 10.

The first two locally acquired chikungunya cases in the continental United States were reported last week in Florida.

The Caribbean epidemic, which began last December and is the first in the Americas, has led to 193 locally acquired cases in Puerto Rico and 2 in the US Virgin Islands, the CDC update noted. Puerto Rican officials declared a chikungunya epidemic on Jul 16.

From 2006 through 2013, the United States averaged just 28 chikungunya cases annually, all of them imported, according to the CDC. The virus does not spread from person to person, but mosquitoes that bite infected people can pass the disease to others.

The Pan American Health Organization put the overall case count in the Caribbean epidemic at 442,310 late last week.
Jul 22 CDC update
Related Jul 17 CIDRAP News story

Study profiles further resistance patterns during MDR-TB treatment

A large, international study to assess the impact of efforts to get second-line treatment to more patients with multidrug-resistant (MDR) tuberculosis (TB) found that treating the condition increases the risk of more resistance, which could be minimized if certain steps are followed.

Researchers from nine different countries, including some from the CDC, published their findings today in Clinical Infectious Diseases.

The team followed 832 patients from 26 clinical sites from Jan 1, 2005, through the end of 2008. Five of the countries participate in the Green Light Committee (GLC), a program designed to increase access to second-line drugs: Estonia, Latvia, Peru, the Philippines, and Russia. Four other non-GLC countries volunteered for the study: South Africa, South Korea, Thailand, and Taiwan. Researchers obtained baseline and monthly sputum cultures. Duplicates of the cultures were sent to the CDC for testing.

Of those without baseline resistance to specific second-line drugs, 8.9% acquired extensively drug-resistant (XDR) TB, 11.2% acquired fluoroquinolone resistance, and 7.8% acquired resistance to second-line injectable drugs. However, the risk of acquiring resistance was lower at GLC-approved sites.

Investigators noted that the findings have important policy implications for programs scaling up services for MDR-TB. For example, they said drug-susceptibility testing should be repeated during treatment and that use of new drugs in regimens without at least two or three other highly effective drugs will contribute to rapidly developing resistance to the new drug.

In an accompany editorial in the same issue, two US experts wrote that there are a number of reasons why MDR-TB patients may develop additional resistance, including variation in drug quality.

They wrote that the study identifies some parameters associated with further drug resistance, though it's difficult to tease out ones that are amenable to intervention. The experts agreed that efforts should be made to ensure that MDR-TB programs embrace GLC features.

However, they disagreed with the study authors' assertion about rapid molecular diagnostics in those who were treated previously. They added that all drug-resistant cases should be diagnosed and started on appropriate treatment as soon as possible.
Jul 23 Clin Infect Dis abstract
Jul 23 Clin Infect Dis editorial

Crucial need cited for continued polio vaccination efforts in Syria

Polio cases in war-torn Syria, which hadn't seen a case since 1999 until the conflict began there 3 years ago, continue to mount and without continued and effective vaccination campaigns will only add to what is already a "humanitarian disaster," says a story from the United Nations (UN) yesterday.

Vaccination coverage in Syria has dropped from an average of 99% to 52% since the war began, says the story, and Syria's health infrastructure has been severely damaged. More than 6.5 million children in the country depend on humanitarian assistance, it notes.

The UN Children's Fund (UNICEF) and the World Health Organization (WHO) have completed the first phase of the largest vaccine campaign in the history of the Middle East, reaching 25 million children under age 5 in seven countries. However, more than 750,000 Syrian children reside in unreachable areas, says the story. More campaigns are planned for October and November.

UNICEF and the WHO have called for "immediate and unhindered access to hard-to-reach children" as well as safe passage for health workers and medical vehicles.

New polio cases have shown up recently in Iraq and Somalia as well as Syria. Estimates say more than half a million children in the latter country live in inaccessible areas.
Jul 22 UN news story
Jun 18 CIDRAP News scan on vaccination campaign