News Scan for Aug 27, 2019

DRC Ebola totals grow
Papaya food safety concerns
Smoking and increased flu risk
Pertussis vaccine in older adults
Barriers to mosquito bites

DRC Ebola total grows by 6 cases, to 2,983

Six more Ebola cases were confirmed in the Democratic Republic of the Congo (DRC) Ebola outbreak, raising the overall total to 2,983, according to numbers reflected today on the World Health Organization (WHO) online Ebola dashboard.

Health officials are still investigating 397 suspected infections. Four more people died from their infections, bringing the fatality count to 1,990.

In other developments, the DRC's multisector Ebola response committee (CMRE) said in an update that one of yesterday's eight case involved a health worker, raising the total number infected in the outbreak to 156, which includes 41 deaths. The report said the worker was vaccinated, but it's not clear how long ago he or she was immunized.

Meanwhile, the WHO's African regional office said in its weekly outbreak and health emergencies update today that the small declining trend in the outbreak seen over the past 3 weeks should be interpreted with caution, amid persistent security challenges and recent disease spread to new areas. The agency added, however, that the lack of new cases in Goma shows how effective proven health measures can be if deployed quickly and effectively.
WHO online Ebola dashboard
Aug 27 WHO African regional office report


FDA calls on papaya industry to improve food safety practices

Citing concerns about recurring Salmonella outbreak linked to imported fresh papayas, US Food and Drug Administration (FDA) officials yesterday sent a letter to the papaya industry asking it to take steps to prevent future outbreaks.

In a statement, Acting Commissioner Ned Sharpless, MD, and Frank Yiannas, MPH, the FDA's deputy commissioner for food policy and response, said that, since 2011 there have been eight Salmonella outbreaks linked to contaminated papayas. One announced in June—linked to Mexican papayas—is still ongoing, with 71 sick from eight states. The other seven events resulted in nearly 500 known illnesses, more than 100 hospitalizations, and 2 deaths.

The FDA officials said the recurring nature of the outbreaks is a clear signal that more needs to be done within all papaya industry sectors to protect customers, including growers, importers, and retailers. "We are urging growers, packers, shippers and retailers in the papaya industry to review their operations and make all necessary changes to strengthen public health safeguards," Sharpless and Yiannas said.

Growers, for example, should assess factors that make their crops vulnerable to contamination, find root causes if a pathogen is found, and implement procedures to minimize contamination. The FDA letter also called on the industry to examine the use and monitoring of water used to grow, spray, move, rinse, or wax crops to identify possible hazards. Also, more steps are needed to improve traceability and rapidly remove potentially contaminated papayas from the marketplace.

The papaya industry should also fund and conduct food safety research to identify possible contamination sources and routes and develop science- and risk-based preventive controls, the officials said.

An investigation into the latest outbreak is still under way, and findings will be released when the probe is complete, the FDA said, adding that officials have stepped up papaya sampling and screening at the border with Mexico.
Aug 26 FDA statement
Jul 8 CIDRAP News scan "CDC notes 9 new Salmonella cases, links outbreak to Cavi brand papayas"


Review finds smokers 5 times more likely to contract flu

Smokers are more than five times more likely than nonsmokers to get sick with lab-confirmed flu, according to a systematic review of nine studies. A research team based at the University of Nottingham published its findings yesterday in the Journal of Infection.

The investigators narrowed their literature search of randomized controlled, cohort, and case-control studies on smoking and flu published through 2017 to nine, of which three were based on lab-confirmed illness with the other six based on influenza-like illness (ILI) symptoms.

Current smokers had an increased risk for flu, and the team found the association was stronger in studies that used lab-confirmed flu, with a pooled odds ratio of 5.69 (95% confidence interval [CI], 2.70 to 11.60). Studies using ILI occurrence found that smokers were 34% more likely to get sick, with a pooled odds ratio of 1.34 (95% CI, 1.13 to 1.59).

The authros note that an earlier study found that, compared with nonsmokers, smoke exposure may suppress innate respiratory mucosal host defense to flu, and that studies on flu severity in smokers have shown inconsistent findings.

The researchers said, however, that the strong association they found between flu infection and smoking raises questions about whether current smoking should be considered an indication for flu vaccination. They also note that an investigation into flu effects on ex-smokers and those who smoke newer electronic cigarettes is warranted.
Aug 26 J Infect abstract


Study shows modest pertussis vaccine protection in older adults

A case-control study in Australia found that the acellular pertussis (whooping cough) vaccine provided only modest protection against the disease among middle-aged and older adults, according to a study yesterday in Clinical Infectious Diseases.

The study included 333 cases and 506 controls aged 46 to 81 years, with an average age of 61. Vaccine effectiveness (VE) against pertussis confirmed by polymerase chain reaction was 52% (95% confidence interval [CI], 15% to 73%). For those who had received the vaccine within 2 years, VE rose to 63%, but the difference was not statistically significant, the authors noted (95% CI, -5% to 87%).

Adjusted VE was similar in adults born before 1950, who would presumably been primed by natural pertussis infection. In that age-group, VE was 51% (95% CE, -8% to 77%).

In a commentary on the study in the same journal Natasha S. Crowcroft, MD, of the University of Toronto, wrote, "This study provides one piece of the 5000-piece pertussis puzzle that will help us decide where adult vaccination fits into the picture."

She adds, "While clinicians and adult patients need to know that pertussis vaccination will halve their own risk of pertussis, what works for individuals does not necessary translate directly into good policy. Currently a regularly scheduled adult pertussis booster is not part of any country's recommendations (although many recommend a single adult pertussis booster and vaccination during pregnancy)." She also points out that adults have about a 1% risk of contracting the disease in any given year.
Aug 26 Clin Infect Dis study
Aug 26 Clin Infect Dis commentary


Graphene-based fabric shows promise as shield from mosquito bites

A graphene-based clothing layer could help shield people from mosquito bites, according to a study yesterday in Proceedings of the National Academy of Sciences.

"Graphene-based materials are being developed for a variety of wearable technologies to provide advanced functions that include sensing; temperature regulation; chemical, mechanical, or radiative protection; or energy storage," the study authors, from Brown University wrote. "We hypothesized that graphene films may also offer an additional unanticipated function: mosquito bite protection for light, fiber-based fabrics."

Through a combination of experiments involving live Aedes aegypti mosquitoes, needle penetration force measurements, and mathematical modeling of mechanical puncture phenomena, the investigators that multilayer graphene films completely inhibited biting by preventing mosquitos from sensing skin- or sweat-associated chemicals used to locate blood meals. The insects landed much less frequently on graphene than on bare skin.

The graphene layer also prevented mosquitoes from penetrating their fascicle, or feeding apparatus, into the skin, except when the fabric was wet. The study was funded by the National Institute of Environmental Health Sciences (NIEHS), part of the US National Institutes of Health.

"These findings could lead to new protective methods against mosquitos, without the environmental or human health effects of other chemical-based repellants," said Heather Henry, PhD, a health scientist administrator with the NIEHS Superfund Research Program, in a NIEHS news release.

William Suk, PhD, director of the NIEHS Superfund Research Program, said, "New material such as this one should be assessed in the field to determine full public health implications."
Aug 26 Proc Natl Acad Sci abstract
Aug 26 NIEHS news release

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