News Scan for May 09, 2017

News brief

Liberian illness cluster blood samples yield serotype C meningitis

The US Centers for Disease Control and Prevention said yesterday that the positive test results for Neisseria meningitidis from four Liberian patients is serotype C, Science reported yesterday. Kai Kupferschmidt, the author of the Science report, said on Twitter today that the tests were on blood and that testing is under way on cerebrospinal fluid samples.

Health officials in Liberia told Science that improved public health training, sample collection, and testing in the wake of West Africa's Ebola outbreak streamlined the recognition and reporting of the unexplained illness outbreak that began in Sinoe County in people who attended the funeral of a religious leader.

Meningitis is now suspected as the cause of the outbreak, though health officials had been also exploring the possibility of point-source contamination of food or water.

According to the Science report, the number of serogroup C infections has been rising in Africa, with Nigeria and Niger fighting large outbreaks. Africa, home of the "meningitis belt" that includes parts of Nigeria and Niger but not Liberia, has made progress against the disease, but the vaccine used there covers only serogroup A.

Since the end of April, the Nigerian outbreak had led to 31 illnesses, 13 of them fatal.
May 8 Science report
Kai Kupferschmidt Twitter feed
May 8 CIDRAP News story "Meningitis suspected in Liberia's mystery illness outbreak"

Study: 46% of elderly patients got unnecessary antibiotics for URIs

A large new study out of Canada has found nearly half of elderly patients with nonbacterial acute upper respiratory infections (AURI) were prescribed antibiotics, despite guidelines that discourage the practice.

The study, published today in the Annals of Internal Medicine, was a retrospective analysis of patients 66 or older who presented with nonbacterial AURI from Jan 1 through Dec 31, 2012. While the primary outcome was the proportion of patients who received an antibiotic prescription within 30 days of their initial primary care visit, the investigators also analyzed characteristics of the patients and the primary care physicians who treated them. They used a multivariable logistics regression model to determine the relationship between those characteristics and antibiotic prescribing rates.

Overall, the investigators identified 185,014 patients aged 66 years or older who were managed by 8,990 unique physicians. The most commonly coded infections were the common cold (53.4%), acute bronchitis (31.1%), acute sinusitis (13.6%), and acute laryngitis (1.6%). Antibiotics were prescribed to 46.2% of patients, and patients who received an antibiotic were more likely than those who did not to have acute bronchitis (45.3% vs. 19.3%) or acute sinusitis (17.1% vs. 10.6%) and have received antibiotics in the previous year (34.2% vs. 27.7%).

The regression analysis showed that patients were more likely to receive antibiotics from mid- and late-career physicians (prescribing rates of 43.5% and 43%, respectively) than from early-career physicians (38.4%); from physicians trained internationally (45.2%) than from those trained in Canada and the United States (41.6%); and from physicians who saw 25-44 or more than 45 patients per day than those who saw fewer than 25 patients a day (43.3% and 44.4% vs. 40.3%). These results remained significant when only the common cold and laryngitis were examined.

The investigators also found that most prescriptions were for broad-spectrum agents, including macrolides, cephalosporins, and fluoroquinolones, despite the fact that broad-spectrum antibiotics are not recommended as initial therapy for any of the conditions studied.

"Our findings should be considered when planning interventions to reduce inappropriate prescribing," the authors of the study write. "Because clinical guidelines and other approaches to behavioral change do not appear to have had the desired effect on practice, further research on alternative strategies to deter inappropriate antibiotic prescribing is needed."
May 9 Ann Intern Med study

Avian Flu Scan for May 09, 2017

News brief

Study finds H7N8 infection dynamics different for turkeys

A series of tests with low-pathogenic and highly pathogenic strains of H7N8 avian flu involved in Indiana poultry farm outbreaks in 2016 found that turkeys are highly susceptible and show different symptoms than infected chickens do. Researchers from the US Department of Agriculture's (USDA's) Southeast Poultry Research Laboratory reported their findings yesterday in PLoS One.

In January 2016, highly pathogenic H7N8 was detected on an Indiana turkey farm, followed by nine more outbreaks at nearby turkey farms that involved the low-pathogenic form of the virus. Genetic testing has shown that both viruses are similar to a low-pathogenic H7N8 detected in wild ducks. To better gauge the risk to poultry, the USDA researchers used both strains to assess infectious dose, shedding, clinical illness, and transmissibility in chickens, turkeys, and mallards.

The lowest mean infectious dose for both virus types was seen in turkeys, and only turkeys showed clinical signs when infected with the low-pathogenic virus. Highly pathogenic H7N8 was deadly for both chickens and turkeys, but clinical signs were different: neurologic symptoms were observed only in turkeys. Also, turkeys had respiratory symptoms after infection with the low-pathogenic virus.

Mallards could be infected by and were able to transmit both viruses, but they didn't show clinical signs. Another key finding was that the mallards were able to contract the virus from chickens.

The mean death time for turkeys infected with H7N8 was shorter than for the highly pathogenic H5N2 virus that struck Midwestern states in 2015, which could mean that H7N8 outbreaks could be easier to control, since the events would be recognized earlier. However, both H7N8 viruses had mean infectious doses that were lower than H5N2 and were more transmissible among turkeys.

Researchers said Indiana's rapid depopulation of infected turkey flocks likely played a major role in limiting the outbreaks, and the lower infectious dose in turkeys and epidemiologic links between turkey farms probably limited the outbreak to turkeys.
May 8 PLoS One abstract

China reports more high-path H7N9 outbreaks in poultry

In the latest avian flu outbreak developments, China reported more highly pathogenic H7N9 detections at live-poultry markets and farms, and Bulgaria reported one more H5N8 outbreak in wild birds, according to the latest notifications from the World Organization for Animal Health (OIE).

China, which reported the highly pathogenic form of H7N9 for the first time in February, noted more outbreaks that occurred from Feb 23 to Apr 28 in three provinces: Hunan in the south-central region, Guangdong in the south, and Hebei in the north.

The Hunan province events began toward the end of February in Chenzhou, striking backyard birds and a livestock market. Guangdong province reported three livestock market detections in three different cities in early March, and Hebei province reported an outbreak that began on Apr 28 at a layer farm that killed 5,000 birds and led to the culling of 25,000.

Bulgaria's H5N8 detection involved a mute swan found dead on Feb 9 in Plovdiv province in the south-central part of the country.
May 9 OIE report on H7N9 in China
May 9 OIE report on H5N8 in Bulgaria