News Scan for Jan 28, 2014

News brief

Case series highlights severe disease with MERS

In addition to severe respiratory failure, nonrespiratory illnesses like shock and kidney injury were common in 12 intensive care unit (ICU) patients in Saudi Arabia who had Middle East respiratory syndrome coronavirus (MERS-CoV) infections, according to a study today in Annals of Internal Medicine.

The study also noted a low rate of MERS-CoV infection among healthcare workers (HCWs) who had contact with MERS patients.

The authors noted that from December 2012 through August 2013, 11 ICU patients (10%) of 114 patients tested in two tertiary care hospitals met the definition of confirmed or probable MERS cases. Three of them were part of a hospital cluster that also included three HCWs, one of whom became critically ill and was the 12th patient in the case series.

All 12 patients had underlying conditions and presented with acute respiratory failure. Eleven (92%) had extrapulmonary manifestations, including shock, acute kidney injury, and thrombocytopenia (deficiency of blood platelets). Only five patients (42%) were alive 90 days after hospitalization. Of 520 exposed HCWs, 4 (0.8%) tested positive for MERS-CoV.

An accompanying editorial by US and Canadian experts applauded the study, saying, "Health care–associated MERS-CoV transmission to patients, workers, and visitors remains significant but is underplayed. Focus on the health care setting may prevent continued human-to-human transmission among at-risk patients."
Jan 28 Ann Intern Med study
Jan 28 Ann Intern Med editorial

Study: Justinian plague arose from novel lineage of Y pestis

What is believed to be the world's first deadly human pandemic of Yersinia pestis, the Plague of Justinian in the 6th to the 8th centuries, was caused by a strain of the organism distinct from the one that caused the Black Death in the 14th to 18th centuries and reemerged in the 19th and 20th centuries, and it died out on its own, say the authors of a study today in The Lancet Infectious Diseases. Their findings suggest that such a pandemic could emerge among humans again, they say.

The researchers studied DNA fragments from the teeth of two persons whose remains were discovered in a German cemetery and were found through carbon dating to live during the time of the Justinian plague. The authors identified a Y pestis–specific pla gene, sequenced it, and compared it with the genomes of 133 contemporary strains and with the draft genome from the second pandemic.

Their phylogenic study showed the Justinian strain to form a novel branch of Y pestis "distant from strains associated with the second and third pandemics" and either extinct or unsampled in wild rodent reservoirs.

The researchers concluded that, because the Justinian plague was distinct genetically from the other two worldwide plagues and no longer exists, there is the possibility that another novel strain of Y pestis could arise and cause a pandemic. The availability of modern antibiotics would lessen the consequences of this occurrence, they note.

"This study raises intriguing questions about why a pathogen that was both so successful and so deadly died out," said expert Edward Holmes of the University of Sydney in a press release. It is possible, he noted, that humans evolved to be less susceptible. David Wagner, first author of the study, said in the press release that climate changes may have affected the bacterium.

The Justinian plague, which factored in the fall of the Roman Empire, had a mortality rate of up to 40%, according to the authors, and killed 30 to 50 million or even, by some estimates, 100 million people. The Black Death and the most recent plague pandemic, both of which have been studied more extensively in terms of genetic analysis, are estimated to have killed almost half of the European population each, says the release.
Jan 28 Lancet Infect Dis study
Jan 27 McMaster University press release

Report: Antibiotic feed additives would not pass FDA muster today

The US Food and Drug Administration (FDA) from 2001 to 2010 quietly tested 30 antibiotic feed additives approved for nontherapeutic use and found that none of them would be approved by the agency today and that 18 of them pose a high risk of exposing people to antibiotic-resistant bacteria, according to a report released yesterday.

The Natural Resources Defense Council (NRDC) said in the report that the 30 penicillin and tetracycline feed additives tested would not only be rejected if submitted today, but 26 of them wouldn't even be approved under 1973 FDA standards, says an accompanying press release. "Nontherapeutic use" refers to giving food animals antibiotics to promote growth or prevent disease rather than to treat illness.

The FDA's scientific review also showed that 18 of the 30 additives pose a "high risk" of exposing people to antibiotic-resistant bacteria, and that the rest lacked sufficient data to determine the risk, the report said.

The NRDC released its report after obtaining previously undisclosed scientific reviews from the FDA after a Freedom of Information Act request and subsequent litigation, the NRDC said.

The group said that it has seen no evidence that the FDA has taken steps since the review process to revoke approvals for any of the additives. "However, we found evidence suggesting that at least nine of these additives are being marketed today," the NRDC said in the release.

The FDA issued the following statement about the report, according to a Food Safety News (FSN) story today: "Based on its review of this and other information, the Agency chose to employ a strategy that would more broadly address the concerns about the production use of medically important antimicrobials in food-producing animals."

It added that the FDA "is confident that its current strategy to protect the effectiveness of medically important antimicrobials, including penicillins and tetracyclines, is the most efficient and effective way to change the use of these products in animal agriculture."
Jan 27 NRDC news release
Jan 27 NRDC report
Jan 27 FSN story

Flu Scan for Jan 28, 2014

News brief

Study: Ferrets given seasonal flu shot had worse H1N1 illness

In a study designed to shed light on a phenomenon seen in Canada of increased risk of pandemic 2009 H1N1 flu in those who received a flu vaccine the year before, ferrets given a seasonal flu shot had worse H1N1 disease than those who had not received the vaccine.

Writing in a study published yesterday in PLoS One, Canadian and Dutch researchers vaccinated 16 ferrets with the pre-pandemic trivalent (TIV, or three-strain) 2008-09 seasonal flu vaccine and 16 ferrets with a placebo. Seven weeks later they inoculated all animals with the 2009 H1N1 virus.

The investigators found that, beginning 2 days after H1N1 challenge, vaccinated animals had greater loss of appetite and weight than placebo animals. The ferrets reached their greatest between-group difference in weight loss relative to baseline 5 days post-challenge.

In addition, vaccinated ferrets had higher lung virus titers and greater lung inflammation 5 days post-challenge. All animals had recovered by 14 days after H1N1 challenge.

The authors conclude, "While they cannot be considered conclusive to explain human observations, these ferret findings are consistent with direct, adverse effect of prior 2008-09 TIV receipt on A(H1N1)pdm09 illness."
Jan 27 PLoS One study

Worldwide flu activity low in some areas, beating baselines in others

As flu activity remains high in North America and China, Europe is just beginning its flu season and levels remain low in most other areas, according to an update yesterday from the World Health Organization (WHO). The large majority (91.6%) of specimens tested from 72 countries worldwide are influenza type A, which includes 2009 H1N1 and H3N2.

The predominant strain in North America is 2009 H1N1, unlike last season when H3N2 was seen most often. In the United States, the proportion of outpatient visits for influenza-like illness (ILI) was 3.6%, above the 2.0% baseline. Deaths from pneumonia and influenza are above baseline, and the proportion of intensive care unit admissions among hospitalized flu patients is 19.4%, higher than any of the past three flu seasons.

Canada is seeing a larger proportion of flu cases this season among 20- to 64-year-olds than among those over 65, a pattern unlike last year.

Both 2009 H1N1 and H3N2 strains are being seen in Europe, with a modest propensity toward the latter (45% vs 55%); predominance depends on the country, but visits for ILI and acute respiratory infection remain low so far, the report says.

H3N2 activity is increasing in Iran and Turkey, as is 2009 H1N1 activity in Egypt. In other areas of northern Africa and central Asia, flu activity remains low. China is seeing an increase in activity, with both 2009 H1N1 and H3N2 dominant in the south and the former dominant in the north. The proportion of patients visiting physicians for ILI in South Korea stands at 27.3%, far above the 12.1% baseline.

Flu activity in Central America, the Caribbean, Africa, and tropical Asia remains low, according to the WHO.
Jan 27 WHO update
Latest (Jan 24) CIDRAP News update on US flu activity