News Scan for Apr 25, 2018

Chikungunya severity
Avian flu outbreaks in 3 nations

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

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