Flu Scan for May 18, 2016

News brief

H5N1 risk factors remain stable during recent case increases

Death rates and demographic characteristics associated with H5N1avian flu infections have remained relatively stable, even in Egypt, where human cases surged dramatically more than a year ago, according to a study yesterday in The Lancet Infectious Diseases.

A research team led by the Chinese Center for Disease Control and Prevention and the World Health Organization (WHO) analyzed 907 human cases of H5N1, 483 (53.3%) of which were fatal, reported globally from May 1997 through April 2015.

Of the 819 (90.3%) patients admitted to the hospital, median time from symptom onset to admission was 4 days. The vast majority of patients (748, or 87.5%) had a history of poultry exposure, and their median age was 19 years. About two thirds of cases (592, or 67.2%) occurred from December to March each year, the authors said.

In Egypt, 363 human H5N1 cases were reported from 2006 to 2015, 116 (32%) of which were fatal. About half of Egypt's total cases (185, or 51%) occurred from Nov 1, 2014, to Apr 30, 2015. Case-patients infected after Nov 1, 2014, were more likely to be older than those infected before that date, with a median age of 26 versus 16.

Case-fatality rates in Egypt were slightly lower after Nov 1, 2014 (28.4% vs 36% before that date). No significant differences were observed in patients' history of exposure to poultry or time from symptom onset to hospital admission after Nov 1, 2014, the authors said.

Because H5N1 has pandemic potential, regular evaluation of seasonal and demographic risk factors will help to monitor potentially dangerous changes in the virus, especially in Egypt, the authors said.
May 17 Lancet Infect Dis study

Study finds cell types might play role in flu vaccine immune response

In the first study of its kind, Mayo Clinic researchers found that certain immune cell subsets appear to be associated with a stronger immune response to the flu vaccine, according to a study yesterday in Immunology.

The investigators measured the levels of several immune cells at baseline and 3 and 28 days after flu vaccination using flow cytometry. They then performed statistical modelling to assess correlations between the levels of cells and day 28 immune responses, as measured by hemagglutination inhibition (HAI), virus neutralizing antibody (VNA), and memory B cell ELISPOT tests.

They found that changes in several cell types from baseline to day 28 and from day 3 to day 28 were found to be significantly associated with immune response, notably the cell-surface proteins HLA-DR and CD86. Baseline levels of B cells and regulatory T cells, in contrast, were able to partially explain the variation they observed in memory B-cell ELISPOT results.

Gregory Poland, MD, from the Mayo Clinic, Rochester, said in a British Society for Immunology (BSI) press release, "This information is important as it allows us to understand why some people might gain better immunity against flu from having the vaccine compared to others. However, we now need to examine the relationship between these factors in more detail to ensure we fully understand how these factors are linked.

"Ultimately, we hope that increasing our understanding of how the immune system functions at a cellular level will allow us to develop more effective vaccines."

The BSI publishes Immunology.
May 17 Immunol study
May 17 BSI press release

News Scan for May 18, 2016

News brief

Study: Fatal cases of Ebola after complete recovery rare

Late death from Ebola disease in survivors of earlier episodes is very rare, occurring in less than 1% of patients in a cohort study of Sierra Leone survivors published yesterday in BMJ. The study additionally found that the infecting dose of Ebola as measured by exposure level does not affect the severity of disease.

The authors, from England and Sierra Leone, several of whom served on response teams in the latter country, followed 151 Ebola survivors discharged from a Sierra Leone treatment center from November 2014 to March 2015 for up to 13 months. Four patients (0.7%) died during a mean follow-up period of 10 months, only one of them after apparent full recovery (late complications or tuberculosis were the likely causes of death in the others).

The households of the 151 survivors comprised 395 people in whom Ebola developed and an additional 53 who had probable Ebola; 227 of the former plus 11 of the latter died of their disease, for case-fatality rates of 57.5% (227/395) and 53.1% (238/448), respectively.

Exposure levels were ascertained by questioning the survivors about symptoms and about who had taken care of them and shared other activities. Household members were also interviewed about their level of contact with the patient and with his or her body fluids. Increasing exposure correlated with increased risk of disease, although no consistent trend was apparent between case-fatality rate and level of exposure.

The authors say their findings of the rarity of recurrent Ebola resulting in death "should be reassuring for Ebola survivors and their contacts, but does not remove the need for continued monitoring of survivors' health."
May 17 BMJ study

CDC reports 133 cases of Salmonella in 26 states tied to small turtles

From Jan 16, 2015, through Apr 8 of this year a total of 133 people from 26 states have become infected with Salmonella linked to contact with small turtles, the Centers for Disease Control and Prevention (CDC) said today. The cases occurred during four outbreaks traced to the Sandiego, Poona, and IIIb 61:i:z53 strains of Salmonella.

The numbers are up from 51 cases in 16 cases involving the Sandiego and Poona outbreaks in the CDC's initial statement on the outbreak, on Oct 9, 2015.

Of the 133 people infected, 38 were hospitalized, but no deaths have occurred, the CDC said. Children 5 years of age or younger account for 41% of the cases.

Of 110 case-patients interviewed, 55 (50%) reported contact with small turtles or their environment (eg, water from their habitat) within the week before their illness developed.

The sale and distribution of turtles with shell length less than 4 inches was banned in the United States by the Food and Drug Administration in 1975. In the current study, 25 (45%) of the 55 case-patients with a known history of contact with small turtles bought them from street vendors.

Turtles carrying Salmonella can appear to be healthy and clean, stresses the CDC, but they can shed the bacteria in their feces, contaminating their bodies and their environment. The agency added that the outbreak is expected to continue at a low level for several months because many people remain unaware of the risk of Salmonella from small turtles and their environment.
May 18 CDC report
CDC advice to pet owners
Oct 12, 2015, CIDRAP News story on outbreak

CDC upgrades pathogen-identifying tool MicrobeNet

The CDC today announced that it has upgraded its MicrobeNet online tool to help labs in hospitals and health departments across the country to identify faster rare pathogens like Elizabethkingia, which has caused recent illnesses in Wisconsin, Michigan, and Illinois.

Since 2013 MicrobeNet has helped lab workers and physicians identify pathogens via DNA sequencing or biochemical testing, the CDC said in a news release. The tool provides access to the CDC's virtual microbe library of more than 2,400 rare and emerging infectious bacteria and fungi at no cost.

Now however, the CDC has partnered with Bruker Corp., of Billerica, Mass., to add a new module to help identify bacteria and fungi faster—in just a few hours. Using Bruker's MALDI Biotyper systems, users will now be able to identify pathogens based on their protein signatures as well as the previous two methods. The new MicrobeNet module will be immediately available to professionals using the Bruker system in labs nationwide, the CDC said.

In addition to being faster, use of the MALDI module in MicrobeNet offers substantial cost savings for clinical and public health laboratories because they no longer will need to develop their own pathogen libraries, the CDC said. The labs will also be assured that their information has been confirmed by CDC experts. In addition, for many bacteria, MicrobeNet provides information about antibiotic resistance.

The CDC's John R. McQuiston, PhD, MicrobeNet team lead, said, "This system helps public health labs and hospitals quickly identify some of the most difficult pathogens to grow and detect. In turn, MicrobeNet will help treat patients faster and allow health departments to respond to public health emergencies more effectively."
May 18 CDC news release
MicrobeNet home page