H7N3 avian flu in US turkey outbreaks related to wild bird strains
The US Department of Agriculture (USDA) last week shared new details about its investigation into H7N3 avian flu outbreaks at turkey farms in North Carolina and South Carolina, one of them involving a highly pathogenic version of the virus.
The outbreaks initially involved low-pathogenic H7N3, occurring earlier this spring at a few commercial turkey farms in both of the states. One of the later events at a South Carolina farm, however, involved highly pathogenic H7N3.
In an Apr 24 update to the World Organization for Animal Health (OIE), the USDA's Animal and Plant Health Inspection Service (APHIS) said genetic sequencing of the viruses suggested a single introduction followed by secondary spread. Mutation of the virus from a low-pathogenic to highly pathogenic virus occurred in one barn at one of the facilities. The sequencing study also found that the H7 virus was distinct from other poultry H7 viruses, but was similar to wild bird H7 viruses, with the hemagglutinin protein similar to those found in North American wild birds from 2016 to 2018.
Scientists said the virus isn't related to the H7N3 strain found in Mexican poultry outbreaks or to H7N9 lineage viruses from China.
Apr 24 OIE report on H7N3 in US turkeys
Apr 10 CIDRAP news scan "High-path H7N3 avian flu strikes South Carolina turkey farm"
Mexico confirms 124 measles cases, with other cases being probed
Public health officials in Mexico have so far identified 1,364 probable cases of measles, 124 of them lab-confirmed, most of them in unvaccinated people, according to a notice from the World Health Organization (WHO).
Of the 1,240 probable but unconfirmed cases identified from Jan 1 to Apr 2, however, 991 were discarded, and 328 are still being investigated. Of the 124 confirmed cases, 105 were in Mexico City, 18 in Mexico state, and 1 in Campeche state. The median age of patients with confirmed measles was 20 years (range, 3 months to 68 years); 59% were male.
"Under vaccination may be linked with missed opportunities for vaccination, a lack of access to vaccination services, scheduling limitations impacting [parents'] abilities to take their children to get vaccinated, or lack of vaccine stocks," the WHO said.
The WHO Region of the Americas was declared measles-free in September 2016 but lost that status after outbreaks occurred in Venezuela and Brazil in 2018 and 2019. In 2019, Brazil reported 19,326 cases, including 15 deaths, while the United States confirmed 1,282 cases.
From Jan 1 to Apr 4 this year, measles outbreaks have been reported in seven countries in the region, leading with Brazil, at 2,194 cases, including 4 deaths. The United States has reported 12 cases so far this year.
Apr 24 WHO measles report
