News Scan for Apr 25, 2018

News brief

Chikungunya severity patterns mimic dengue, malaria

A study today in Clinical Infectious Diseases tracked two waves of chikungunya infections in Nicaragua, demonstrating that outbreak intensity is linked to more severe clinical presentations of the mosquito-borne disease.

Chikungunya is a relatively new virus to hit Central America, and researchers designed a prospective cohort study based in Managua to track the disease in 4,353 children ages 2 to 14 years from 2014 to 2016. The children provided annual serum samples as part of the study.

The first epidemic wave in 2014-2015 was smaller (95 cases) than the second wave in 2015-2016 (444 cases), with an incidence during the first wave of 27.3 cases per 1,000 person-years, compared with 142.1 cases per 1,000 person-years during the second wave.

The researchers used clinical observation of symptoms, including joint pain, fever, muscle pain, and headache to gauge severity, with the second epidemic showing a higher proportion of symptomatic infections and a higher odds of systemic symptoms in patients, the authors said.

"A relationship between the force of infection and the proportion of symptomatic infections has been observed in other vector-borne infectious diseases, including dengue and malaria," the authors said.
Apr 25 Clin Infect Dis study


Avian flu outbreaks reported in Finland, Mexico, France

In the latest avian flu outbreak developments, Finland and Mexico reported new highly pathogenic virus detections involving different strains, and France reported a lowpathogenic outbreak at a duck farm, according to updates from the World Organization for Animal Health (OIE).

Finland today said H5N6 was detected in a white-tailed eagle found dead on Apr 18 in Western Finland province. The country reported a similar finding in a wild bird in late March.

Elsewhere, Mexico on Apr 21 reported two poultry outbreaks involving the H7N3 virus, one in Queretaro state and the other in neighboring Guanajuato state, both in the south central part of the country. The outbreaks began on Apr 12, one of them at a backyard location where fighting birds were kept.

Taken together, the virus killed 1,598 of 2,664 birds, and the rest were culled as part of control measures. Mexico reported its last H7N3 outbreaks in March in the same two states.
Apr 25 OIE report on H5N6 in Finland
Apr 21 OIE report on H7N3 in Mexico

In low-pathogenic developments, France reported an H5N3 outbreak at a duck farm in Lot-et-Garonne department in the country's southwestern region. Authorities detected the virus on Apr 17 after samples were taken after repopulation at a previous outbreak site.

The farm's 12,240 foie gras ducks were destroyed on Apr 19 as part of the outbreak response. France has reported several H5N3 outbreaks, along with those involving other strains, in the foie gras production areas since 2015, but the past winter saw fewer outbreaks.
Apr 23 OIE report on H5N3 in France

Food Outbreak Scan for Apr 25, 2018

News brief

CDC: 31 more sickened by E coli-tainted romaine lettuce

Today the Centers for Disease Control and Prevention (CDC) reported 31 more cases of foodborne illness in a multistate Escherichia coli O157:H7 outbreak linked to romaine lettuce. There are now84 ill people from 19 states (3 more states than the last update on Apr 18) identified in this outbreak.

To date there have been no deaths in the outbreak, but the CDC said nine patients have developed a type of kidney failure called hemolytic uremic syndrome, one of the most severe outcomes of E coli infections.  

Typically, outbreaks caused by E coli O157:H7 result in a 30% hospitalization rate, the CDC said, but this outbreak, which was first reported by the CDC on Apr 10, has yielded a hospitalization rate of 54%. Officials are working to determine why this strain is causing more hospitalizations. Dates of first symptoms range from Mar 13 to Apr 12.

According to the CDC, 64 (96%) of 67 people interviewed reported eating romaine lettuce in the week before their illness started. The romaine is from a growing region around Yuma, Ariz., and most commonly served pre-chopped in salads.

"Do not eat or buy romaine lettuce unless you can confirm it is not from the Yuma, Arizona, growing region," the CDC said. "Product labels often do not identify growing regions; so, do not eat or buy romaine lettuce if you do not know where it was grown."
Apr 25 CDCupdate


South Africa's Listeria outbreak slows, but case total still growing

South Africa continues to report more illnesses in its Listeria outbreak linked to a ready-to-eat meat product, the world's largest of its kind.

In an Apr 20 update, the country's health department said eight more cases were reported during the previous week, one of which occurred in October 2017. As of Apr 17, the number of confirmed cases had risen to 1,019, with 199 deaths reported so far.

The outbreak has had been linked to polony, a meat product similar to bologna, from an Enterprise Foods production facility. Polony samples from the factory tested positive for the Listeria monocytogenes outbreak strain. The products were recalled on Mar 4, and although cases have declined since then, 50 more cases have been reported. The disease has a long incubation period of up to 70 days, and implicated products have a long shelf life. At the height of the recall, the health department was recording 30 new cases each week.

In March, World Health Organization raised concerns about the outbreak, given that the polony products had been exported to 15 African countries.
Apr 20 South Africa Department of Health outbreak update

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