News Scan for Jun 11, 2014

News brief

Report profiles first fatal Heartland virus case

A recently published case report on the nation's first death from Heartland virus, in an 80-year-old man who had been reported as Tennessee's first case, sheds light on the clinical profile and hints that older people who have underlying complications may be more vulnerable to complications from the disease.

Researchers from the US Centers for Disease Control and Prevention and Vanderbilt University reported their findings Jun 9 in Clinical Infectious Diseases (CID).

The man's illness was first noted in a Mar 28 report in Morbidity and Mortality Weekly Report. The CID report, however, contains several more details about his illness, along with autopsy findings.

The patient lived on a farm in central Tennessee and was active outdoors. He had a history of tick bites, and his wife found one on him 2 weeks before he got sick in July 2013. The man had a history of chronic obstructive pulmonary disease and heavy alcohol use. Symptoms when he sought care in his local emergency department included weakness, frequent falls, altered mental status, and fever.

His lab profile over the course of his hospitalization was marked by hemorrhagic manifestations and multiple organ failure, and he died 15 days after he was hospitalized. Tests on autopsy samples were negative for Ehrlichia, Anaplasma, spotted fever group Rickettsia, and Leptospira species. The team wrote that the clinical history and negative tests raised suspicions that the man was infected with Heartland virus, which was detected at autopsy in his lymph nodes and spleen.

Researchers concluded that the man's age, weakened immune system, and chronic medical conditions probably predisposed him to a more severe illness and fatal outcome, similar to a pattern seen in China among patients who have severe fever and thrombocytopenia syndrome virus infections. They said the clinical course of Heartland virus infection mimics severe Ehrlichia chaffeensis infection, but patients don't improve with doxycycline treatment.

Genetic analysis of the virus showed enough divergence from Missouri strains to suggest that the virus has been circulating in Tennessee ticks for some time. The findings expand the geographic range of the disease—which is believed to spread through lone star ticks—beyond Missouri where the first cases were detected.

In late May Oklahoma health officials reported the state's first case, which also proved fatal, raising the number of infections so far to 10, 2 of them fatal.
Jun 9 Clin Infect Dis abstract
Mar 27 CIDRAP News scan "
CDC reports 6 more cases of Heartland virus infection"
May 27 CIDRAP News scan "
Oklahoma reports fatal Heartland virus case"


Porcine epidemic diarrhea virus confirmed in Colombia

Colombia has reported its first outbreaks of porcine epidemic diarrhea virus (PEDV), which have affected more than 3,000 swine in 45 holdings in various parts of the country, according to a Jun 9 report filed with the World Organization for Animal Health (OIE).

Of 18,552 susceptible commercial and backyard pigs, 3,328 were infected with PEDV and 1,054 died, for an 18% morbidity rate and a 32% case-fatality rate. The outbreaks started in March with diarrhea and deaths in piglets and continued through May. Forty-two of the outbreaks have been in Cundinamarca and Huila departments in the central part of the country.

Authorities have implemented surveillance and control measures, including quarantine, disinfection of premises, enhanced biosecurity steps, and control of animal movement.

The report said morbidity and mortality rates are lower than those observed in other countries such as the United States, Canada, and Mexico, and farms' production levels have rebounded in less than 2 weeks.
Jun 9 OIE report

Experiments suggest a 1918-like flu virus could rise again

Avian influenza viruses with components similar to those in the 1918 pandemic flu virus still circulate in nature, and genetic engineering experiments suggest it would take only a few mutations to turn them into a human threat, according to a team of scientists led by Yoshiro Kawaoka, DVM, PhD, of the University of Wisconsin.

Writing in Cell Host & Microbe, Kawaoka and colleagues say their studies have shown "the global prevalence of avian influenza virus genes whose proteins differ by only a few amino acids from the 1918 pandemic influenza virus, suggesting that 1918-like pandemic viruses may emerge in the future." The genes are found in viruses circulating in wild ducks, according to a University of Wisconsin press release.

To assess the risk, the team used reverse genetics to generate a virus with gene segments encoding proteins very similar to those of the 1918 virus. They found that this virus was more pathogenic in mice and ferrets than a natural avian flu virus, causing flu-like symptoms, but not as pathogenic as the 1918 virus.

In further experiments, they found that seven amino-acid changes in this virus's polymerase and hemagglutinin proteins gave it the ability to spread in ferrets via respiratory droplets, the report says. It adds that the findings suggest "that the potential exists for a 1919-like pandemic virus to emerge at any time from the avian virus gene pool."

Kawaoka said that knowing which avian flu virus genes to look for can help scientists predict the likelihood of an emerging strain of pandemic flu, according to the release.

The experiments were conducted under biosafety level 3 precautions, the second-highest safety level. The press release says the manuscript was reviewed by the National Institute of Allergy and Infectious Diseases, in keeping with US policy on "dual-use research of concern" (DURC).

The researchers found that blood serum from people vaccinated with the current seasonal flu vaccine reacted with the 1918-like virus, suggesting that the vaccine could be protective against it. Also, the authors say the viruses used in the study are likely to be "highly susceptible" to the antiviral drug oseltamivir.

Other scientists not involved in the research weren't so reassuring. In a story in The Guardian today, Simon Wain-Hobson, PhD, a virologist at the Pasteur Institute in Paris, said, "It's madness, folly. It shows profound lack of respect for the collective decision-making process we've always shown in fighting infections."

Harvard epidemiologist Marc Lipsitch, PhD, commented, "This is a risky activity, even in the safest labs. Scientists should not take such risks without strong evidence that the work could save lives, which this paper does not provide." Lipsitch co-wrote a commentary last month in PLoS Medicine calling for safer alternatives to DURC.
Jun 11 Cell Host & Microbe abstract
Jun 11 University of Wisconsin
press release
Jun 11 Guardian story
May 22
CIDRAP News story on Lipsitch DURC commentary


Study shows potential for ocular-only influenza infection

Ferrets experimentally infected with either avian or human influenza strains through only the eyes readily transmitted the virus to other ferrets, and those inoculated with low levels of H5N1 avian flu via that route died, according to a study today in the Journal of Virology.

Researchers in the Influenza Division of the Centers for Disease Control and Prevention (CDC) first inoculated 11 ferrets via aerosol to the eyes with H5N1 viruses at various doses and for exposure times from 2 to 30 minutes. Only 1 of those ferrets survived, and the experiment showed that H5N1 via the ocular route can be fatal to ferrets even when administered for 2 minutes and at doses as low as 10 plaque-forming units.

The investigators then inoculated ferrets with H7N3, H7N7, and H7N9 avian flu strains, as well as with pre-pandemic H1N1 and variant H3N2 human strains. They found that, with all strains, the infected ferrets shed virus for prolonged periods and were able to transmit influenza by either direct contact or via respiratory droplets.

The authors conclude, "Ocular-only exposure to virus-containing aerosols constitutes a valid exposure route for a potentially fatal respiratory infection . . . In the absence of eye protection, the human ocular surface remains vulnerable to infection with aerosolized respiratory viruses."
Jun 11 J Virol study


Federal settlement to cover woman's flu vaccine claims

A Philadelphia law firm announced yesterday that it had negotiated a settlement worth up to $11.6 million to pay for ongoing medical costs of a 24-year-old former nurse's aide who had symptoms 3 weeks after getting a flu shot in 2010 that were later diagnosed as Guillain-Barre syndrome (GBS), the Morning Call, a newspaper based in Allentown, Penn., reported yesterday.

The settlement will be paid by the National Vaccine Injury Compensation (NVIC) program, a federal program designed to handle claims related to seasonal flu vaccines and routine childhood immunizations.

The woman received the vaccine at work in October 2010. Though Lehigh Valley Hospital, where she worked, now requires employees to be vaccinated against influenza, the requirement was not in place when the woman was immunized, and the facility was not named as a defendant. She has been in a hospital or nursing homes for nearly 4 years and cannot walk, feed, or clothe herself.

The settlement, negotiated by attorneys Lawrence Cohan and David Carney, also provides the woman with more than $1 million in lost wages, pain, suffering, and other expenses, according to the report.

Carney told the Morning Call that the case was clear: The woman was previously healthy, and symptom onset closely match medical literature reports for GBS caused by flu vaccine, and there was no other explanation for her illness. Studies have suggested that there is a negligible risk of developing GBS after getting the flu vaccine, but health officials have said the health risks from flu outweigh the vaccine risk. Studies have also suggested that flu infection is a likely risk factor for GBS.
Jun 10 Morning Caller story

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