News Scan for Nov 03, 2015

Ebola travel updates
;
Axing vaccine refusers
;
H5N2 in Taiwan, South Africa
;
West Nile hits birds hard

CDC scales back Ebola travel advisories for Sierra Leone, Liberia

The US Centers for Disease Control and Prevention (CDC) yesterday stepped down its travel warnings for both Sierra Leone and Liberia, with Ebola activity continuing at zero weekly cases in both countries.

Liberia was declared free of the disease for a second time on Sep 3, and Sierra Leone will reach that mark on Nov 7 if no new cases are detected before then.

The change for Sierra Leone is a downgrade from its highest warning level 3 (red) to alert level 2 (yellow), signifying that Americans are no longer advised to avoid all nonessential travel to the country. Instead, travelers are urged to take enhanced precautions.

For Liberia, the CDC moved the warning from alert level 2 to watch level 1 (green), meaning US residents are no longer advised to take extra precautions, but as usual should avoid contact with sick people, dead bodies, blood, and body fluids.
Nov 2 CDC Sierra Leone update
Nov 2 CDC Liberia update

In related developments, a study of nearly 1,000 Ebola cases from the Democratic Republic of Congo (DRC) over the past 38 years found that each day hospitalization is delayed is associated with an 11% increased risk of death during epidemics. British researchers and their collaborators from the DRC published their findings today in the journal eLife.

Their profile of DRC Ebola cases since 1976 when the virus was first identified also found that quickly progressing outbreaks are swiftly brought under control, but responses were slower and outbreak duration was longer in slowly growing events. The team also found that adults 25 to 64 years were more likely to be sickened by Ebola, a similar pattern seen in West Africa's outbreak.

The researchers concluded that their findings support the importance of rapid hospitalization and could help target interventions such as vaccines if supplies are in tight supply.
Nov 3 eLife abstract
Nov 3 eLife press release

 

Survey finds 1 in 5 pediatricians cut off vaccine-refusing families

About 1 in 5 pediatricians and 1 in 20 family physicians (FPs) dismiss families from their practice if they refuse the recommended childhood vaccinations, researchers from Colorado and the US Centers for Disease Control and Prevention said in a study in Pediatrics yesterday.

The results are based on a 2012 survey of 534 primary care physicians and indicated that 21% of pediatricians and 4% of FPs reported always or often dismissing families if they refused one or more recommended vaccine. Pediatricians who dismissed families were more likely to be in private practice (adjusted odds ratio [OR], 4.90), from the South (OR, 4.07), and reside in a state without a philosophical exemption law (OR, 3.70).

Overall, 83% of physicians said that more than 1% or more of parents refused infant vaccines in a given month, and 20% said that more than 5% did. Fifty-one percent reported always or often requiring parents to sign a form if they refused immunization (pediatricians, 64%; FPs, 29%).

"Even though the American Academy of Pediatrics discourages providers from dismissing families, some providers continue to do so," said Sean O'Leary, MD, MPH, University of Colorado associate professor of pediatrics in a university press release. "Instead of dismissing families, we need a better understanding of the reasons for vaccine refusal to find evidence-based strategies for communication that are effective at convincing hesitant parents to vaccinate."
Nov 2 Pediatrics abstract
Nov 2 University of Colorado news release

 

H5N2 affects chickens and ducks in Taiwan, ostriches in South Africa

Highly pathogenic H5N2 has hit four farms and an abattoir housing more than 36,000 poultry in Taiwan, while its low-pathogenic form has affected more than 13,000 ostriches on 11 farms in South Africa, the World Organization for Animal Health (OIE) noted in separate reports late last week.

In Taiwan, the four affected farms include two neighboring duck holdings in Yunlin County in the west and a chicken farm in nearby Changhua County, as well as a duck farm in Pingtung County in the south, according to an Oct 30 OIE report. The farms had flocks ranging from 3,274 to 22,000 poultry.

The affected abattoir is in Taitung County in the southern part of the island. It held 750 chickens. The outbreaks started anywhere from Sep 9 to Oct 20.

All told 2,006 birds were infected with H5N2 and 1,940 died. The remainder of the flocks were culled to prevent disease spread. Taiwan has battled a host of avian flu outbreaks this year caused by H5N2 and H5N8. Yunlin has been one of the hardest-hit counties.
Oct 30 OIE report on Taiwan

In South Africa, meanwhile, 11 outbreaks of low-pathogenic H5N2 in August, September, and October have affected flocks of 13,486 ostriches in Western Cape province, the OIE said on Oct 30.

Flocks range in size from 180 to 3,038 birds, and the outbreaks began as early as Aug 12 and as recent as Oct 6. Six of the outbreaks began in September.

Together 6,033 birds contracted the virus, but none died and no culling was necessary. Measures such as quarantine and controlling the movement of ostriches have been implemented, according to the report.
Oct 30 OIE report on South Africa

 

Study shows severe, prolonged impact of West Nile on US birds

Using more diligent methods than in previous studies, scientists found that millions more birds die from West Nile virus each year than previously thought, and the disease can diminish bird populations year after year, according to a study yesterday in Proceedings of the National Academy of Sciences.

West Nile significantly damaged survival rates in 23 of 49 bird species examined, or 47%, compared with around 33% in previous studies, the US team reported.

Previous estimates of disease effect were based largely on the Audubon Society's traditional Christmas Bird Count, a 115-year-old tradition in which volunteers count birds in late December each year. The new data were collected more systematically via 574 bird-banding stations operated by the Institute for Bird Populations nationwide, according to a University of California-Los Angeles (UCLA) press release.

The team studied data from 1992 through 2007, before and after West Nile spread across the United States from 1999 through 2003.

The virus affected different species differently, the study showed. Among the roughly 130 million red-eyed virios in the United States, the researchers estimated the virus killed 29% in a year, or more than 37 million. But survival rates of red-eyed vireos rebounded a year after their exposure to West Nile virus.

Contrast that with warbling vireos, who had a death rate of just 9%. They, however, continued to have lower survival rates after first being infected. The investigators determined that survival in 11 species was affected only during the initial spread of the disease, whereas 12 species showed no signs of recovery since West Nile introduction.

Author Ryan Harrigan, PhD, with UCLA's Center for Tropical Research and Institute of the Environment and Sustainability, said of the latter group, "These populations are getting hammered—over 5 years, they're losing a third of their population. . . . In some species, this has gone on 5 or 6 years after the disease hit, so the idea that the populations have not recovered since then is a bit scary."
Nov 2 Proc Natl Acad Sci abstract
Nov 2 UCLA press release

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