News Scan for Dec 14, 2015

Acute gastroenteritis in the US
;
More chikungunya cases
;
Ebola and bleeding

CDC notes norovirus common culprit in gastroenteritis cases

The first report from a surveillance system launched by the US Centers for Disease Control and Prevention (CDC) in 2009 to examine the acute gastroenteritis outbreak patterns that aren't part of foodborne or waterborne outbreaks found that noroviruses was by far the most frequently reported cause, with Shigella and Salmonella also making up a portion of the illnesses.

Researchers reported their findings from the National Outbreak Reporting System (NORS) on Dec 11 in Morbidity and Mortality Weekly Report (MMWR).

NORS is a national voluntary reporting system designed to look at acute gastroenteritis outbreaks that result from contact with contaminated environmental sources, infected people or animals, or unknown sources. Researchers said 10,756 such outbreaks were reported from 2009 through 2013, resulting in 356,532 illnesses, 5,394 hospitalizations, and 459 deaths.

Outbreaks occurred more often in the winter, corresponding to the norovirus season, and with long-term care facilities as a frequent setting. Outbreaks caused by Shigella, Salmonella, and other pathogens were often identified in childcare facilities.

Of the total, 85% involved person-to-person contact, 15% had an unknown transmission mode, and 0.4% were linked to contact with a contaminated environmental surface. Researchers noted that the number of cases over the covered time span nearly doubled, a sign that NORS reporting improved.

The team concluded that further study of acute gastroenteritis outbreaks could better help understand the pathogens and how they spread and that a closer look at outbreaks of an unknown source could help reveal barriers to identification.
Dec 11 MMWR report

 

Outbreak cases of chikungunya increase by 1,400

Cases of chikungunya in the Americas and Caribbean rose by only 1,432 last week, bringing the outbreak total to 1,789,490, according to a Dec 11 Pan American Health Organization (PAHO) update.

The agency's previous two updates included 2,556 and 17,398 new cases, respectively, with the latter update including 2 weeks' worth of data. The new infections bring the total this year to 642,721 suspected and confirmed cases. No new deaths were reported, keeping that total at 77.

The vast majority of new cases were reported by Colombia, which often has had the most weekly cases this year. It had 1,049 new cases, to bring its 2015 total to 355,347 cases. Mexico was second with 290 new cases and 11,070 for the year. Many countries, however, have not supplied a chikungunya update to PAHO for weeks.

The epidemic began in December 2013 with the first locally acquired chikungunya case ever reported in the Americas, on St. Martin in the Caribbean.
Dec 11 PAHO update

 

Study: Ebola in West Africa tied to less bleeding than in earlier outbreaks

The incidence of hemorrhagic symptoms in the current West Africa has been much lower than in previous outbreaks elsewhere in Africa, a phenomenon that has been noted previously, according to a new meta-analysis in BMC Infectious Diseases.

Italian and UK scientists analyzed data from 5 studies on Ebola cases in West Africa and 10 on previous outbreaks in Eastern-Central Africa. In aggregate, the studies contained information on 4,278 Ebola patients with gingival bleeding, 3,859 with nasal bleeding, and 4,867 with conjunctival bleeding.

The researchers found that the incidence of gingival bleeding was 18.0% in West Africa, compared with 45.3% farther east. Incidence of nasal and conjunctival bleeding was 1.3% and 1.9%, respectively, in West Africa, compared with 10.6% and 24.2%, respectively, in East-Central Africa.

The authors also noted that the relative frequency of gingival bleeding decreased by two-thirds during West Africa's Ebola outbreak, and the say their findings may lend credence to the hypothesis that the virus has adapted more to humans in the current outbreak.
Dec 11 BMC Infect Dis study

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