News Scan for Aug 19, 2014

Flu evolution in pigs
;
MERS-CoV in African camels
;
Lab incident findings
;
Vaccine-resistant polio
;
WHO gets large Saudi gift for Iraq

Study: Flu viruses can quickly evolve, gain transmissibility in pigs

In a study designed to simulate how the pandemic 2009 influenza (pH1N1) virus might have evolved, researchers say it took only nine passages in pigs for a virus to gain "greatly enhanced virulence and transmissibility" in pigs, guinea pigs, and ferrets.

Writing in the Journal of Virology, the team of Chinese, American, and British researchers says there is no clear evidence that the pH1N1 virus stemmed from a direct precursor in pigs. They started with a reassortant H1N1 virus that was phylogenetically similar to pH1N1 in that it had two gene segments from a Eurasian avian-like H1N1 swine flu virus and six segments from a triple-reassortant H3N2 virus, but it had limited virulence and transmissibility in animal models.

The authors infected a pig with this virus, collected samples from the animal 4 days later, and used them to infect another pig, repeating the process until nine pigs had been infected. They found that the severity of infection increased with each pig in the series.

When the researchers analyzed viruses collected from the last pig in the series, they found that they shared five amino acid mutations and that mutations in the hemagglutinin (HA) protein differed greatly between the upper and lower respiratory tracts. Three representative viral clones were found to have enhanced replication, pathogenicity, and transmissibility in pigs, guinea pigs, and ferrets, compared with the parent virus.

In addition, one particular viral clone that had the five consensus mutations plus three HA mutations was "able to infect ferrets by airborne transmission as effectively as the pandemic virus" the report says.

"Our findings suggest that pigs can readily induce adaptive mutational changes to a precursor pandemic-like virus to transform it into a highly virulent and infectious form akin to that of the pandemic H1N1/2009 virus which underlines the potential direct role of pigs in promoting influenza A virus pathogenicity and transmissibility," the report says.
Aug 6 J Virol abstract

 

Signs of MERS-CoV found in camels in Nigeria, Tunisia, Ethiopia

Scientists recently reported finding antibodies to MERS-CoV (Middle East respiratory syndrome coronavirus) or a close relative thereof in camels in Nigeria, Tunisia, and Ethiopia, while another team said a MERS-CoV virus from a camel in Qatar closely matched the virus found in a Qatari MERS patient in 2012. Both studies were published in the August issue of Emerging Infectious Diseases.

Other studies have shown the presence of MERS-CoV itself or MERS-CoV–like antibodies in camels in several Middle Eastern countries, Egypt, Sudan, and Somalia, possibly for decades.

In the first study, the researchers sampled 358 camels in four Nigerian provinces, 204 camels in three Tunisian provinces, and 188 camels in three provinces of Ethiopia. The sample collection time frame was 2009 to 2013.

The samples were tested for antibodies to MERS-CoV, the SARS (severe acute respiratory syndrome) coronavirus, and the human coronavirus OC43, a proxy for bovine coronavirus, which commonly circulates in dromedaries.

Most of the samples from Nigeria and Ethiopia tested positive for MERS-CoV or a similar virus: 94% of adult samples from Nigeria, and 93% of adult and 97% of juvenile samples from Ethiopia. As for the Tunisian samples, 30% of juvenile camels and 54% of adult camels tested positive.

Most of the camels from all countries tested positive for OC43, while none tested positive for the SARS coronavirus.

"A question raised by these findings is whether human cases occur outside the Arabian Peninsula and if such cases are currently underdiagnosed in Africa," the authors write. They suggest that awareness of MERS-CoV should be raised among African clinicians.
August Emerg Infect Dis report (Nigeria et al)

In the other study, researchers found MERS-CoV in an 8-month-old camel that was among 53 healthy camels tested in Doha, Qatar, in February 2014. They sequenced the virus's full genome and found that it was highly similar to human MERS-CoV. It was most closely related (99.9% identity) to an isolate from a Qatari patient who was treated in England in 2012 and was distinct from strains found in camels elsewhere in Qatar.

The findings support the hypothesis that camels are a reservoir for human MERS-CoV and can pass the infection to humans, but they don't prove that direct exposure to camels causes human cases, the authors say.
August Emerging Infect Dis report (Qatar)
Related Aug 18 CIDRAP News item

 

Newspaper report probes lab accident data

A report based on a federal data request by USA Today found that more than 1,100 lab incidents with pathogens or toxins considered bioterror risks occurred from 2008 through 2012. In about half of the incidents, lab workers sought medical evaluation or treatment, according to the Aug 17 USA Today story. All of five laboratory workers in whom infection or illness was confirmed recovered.

The story is based on reports from government, university, and private labs that are registered with the federal Select Agent Program. Some of the data in the USA Today analysis—that from 2008 through 2010—overlaps a 2012 report on lab safety incidents by US Centers for Disease Control and Prevention (CDC) researchers in the journal Applied Biosafety.

According to the USA Today investigation, the annual number of lab incidents ranged from 116 in 2008 to 247 in 2012. They occurred in regulated research labs as well as unregistered labs, which are required to report incidents in the event that they identify a select agent.

The story said categories of incidents covered in the reports included bites or scratches from infected animals, needle sticks, failures of personal protection equipment, spills, and specimen packages that temporarily went missing after they were shipped.

The paper's report notes that detailed information about the incidents isn't disclosed because it is protected under federal biosecurity laws. However, Gigi Kwik Gronvall, PhD, an immunologist and associate professor at the University of Pittsburgh School of Medicine, told the paper that lab accidents can occur even in high-security labs that have redundant safety systems. She said moving to a more transparent no-fault reporting system would better describe the incidents so that other labs can learn how to prevent and manage them.
Aug 17 USA Today story
Jan 22, 013, CIDRAP News story "Select-agent safety report finds little public health risk

 

Variant polio virus in 2010 Congo outbreak accounted for high lethality

A large and highly lethal 2010 polio outbreak in the previously polio-free Republic of Congo, with many cases occurring in people who had been vaccinated, involved a variant wild poliovirus type 1 (WPV1) that allowed immune escape, according to a study published yesterday in the Proceedings of the National Academies of Science.

A WPV1 isolated from a fatal case (termed PV1-RC2010) was found to have a combination of amino acid exchanges in critical antigenic site 2 (AgS2) that was previously unknown. The exchanges were found in 11 additional WPV1 isolates from fatal cases. Patients who had fatal cases showed evidence of previous polio vaccination.

The exchanges rendered the virus resistant to neutralization by three different monoclonal antibodies (mAbs) relevant for AgS2 as well as vaccine-derived antibodies, pointing to immune escape as contributing to the severity of the outbreak, say the authors.

The Congo outbreak included 445 laboratory-confirmed cases. The 47% case-fatality rate was unusually high, and the median age of patients with paralytic disease was 20 years. Vaccine-mediated immunity against the outbreak strain was not investigated.

The results illustrate the need for sustained vaccination coverage as well as clinical and environmental surveillance for variant polioviruses as the world closes in on eradicating polio, said the authors.
Aug 18 Proc Natl Acad Sci abstract

 

Saudis give WHO unprecedented gift for Iraq health crisis

A grant to the World Health Organization (WHO) in the amount of $US 50 million has been provided by Saudi Arabia to aid in the health crisis in Iraq caused by the ongoing conflict there. The donation is the largest ever given to the agency  for a specific crisis, said a press release from the WHO's Regional Office for the Eastern Mediterranean yesterday.

Health emergencies in Iraq are mounting because of massive numbers of Iraqis displaced by the violence, hundreds of thousands of Syrian refugees escaping warfare in their own country, and the resulting strain on an already stretched health system. "Even before the current crisis, Iraq's health system and the health of its people were facing major challenges," Dr. Syed Jaffar Hussain said, adding, "This has only been exacerbated by the new waves of insecurity in many parts of the country."

Outbreaks of infectious diseases such as cholera, diarrheal diseases, measles, and hepatitis have increased and are a continuing threat. Among the health problems WHO intends to target are widespread malnutrition and diarrhea as well as low immunization rates in children. The organization aims to cut in half the number of diarrhea cases, to increase polio vaccination rates (for example, from the current 48% to over 94% in Anbar province), and to improve emergency obstetric care.
Aug 18 WHO news story

 

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