Low-pathogenic H5N1 virus prompts turkey culling in Missouri
Authorities have destroyed a flock of 39,000 turkeys on a farm in southwestern Missouri following the detection of a low-pathogenic H5N1 avian influenza virus in the birds, according to a report that US officials filed with the World Organization for animal Health (OIE) on May 2.
The virus was found through routine surveillance testing, and none of the birds were sick, says the report from the US Department of Agriculture (USDA). The virus is closely related to low-pathogenic H5N1 isolates found in US wild birds, officials said.
The virus was detected Apr 26 on a farm in Jasper County, near Missouri’s southwestern corner, and the finding was confirmed 4 days later by a USDA laboratory, according to the report. The pathogen was found in samples from healthy turkeys.
In addition to culling all the turkeys on the farm, authorities have quarantined the site and are conducting an epidemiologic investigation and enhanced surveillance and testing in the area, the report says. The Missouri Department of Agriculture is working with the USDA Animal and Plant Health Inspection Service on the effort.
Partial sequencing of the virus’s hemagglutinin and neuraminidase proteins shows it is 98% similar to a 2011 H5N1 isolate from a mallard duck in Ohio. It also bears 99% similarity to an isolate found in a blue-winged teal in Louisiana in 2014.
One turkey farm in Jasper County was hit in March 2015 by the highly pathogenic H5N2 avian flu virus that struck hundreds of turkey and chicken farms in the Midwest that spring. The outbreak killed and forced the culling of tens of millions of birds, most of them in Iowa and Minnesota.
May 2 OIE report
Mar 10, 2015, CIDRAP News story on H5N2 outbreak in Missouri
H5N6 sickens another in China, WHO notes hospital spread with H7N9
A 65-year-old woman from China's Anhui province is hospitalized in critical condition with an H5N6 avian influenza infection, the country's 13th such case since 2014, according to a statement yesterday from Hong Kong's Centre for Health Protection (CHP). Also, the World Health Organization (WHO) weighed in on 17 recent cases from China, including an instance of possible human-to-human transmission between hospital patients.
An investigation revealed that the woman had contact with poultry before she came down with symptoms on Apr 24. She was hospitalized on Apr 27 and is listed in critical condition.
The pace of H5N6 illnesses in China has picked up in recent months, with 10 cases reported since the end of December. The last few cases were reported in April. Though a handful of Asian countries have reported H5N6 in poultry, China is the only one to report human infections. In an earlier risk assessment, the World Health Organization (WHO) said it is closely monitoring the situation and that most patients had been exposed to live poultry before they got sick.
May 3 CHP statement
In other avian flu developments, the WHO said yesterday that on Apr 18 China notified it of 17 more lab-confirmed H7N9 cases, 5 of them fatal. All of the cases had been noted in official statements from China's provincial health departments or in government monthly infectious disease updates.
The WHO said onset dates ranged from Feb 21 to Mar 20, with patient ages ranging from 26 to 86 years. Eleven of the patients were men, and 15 of the patients had been exposed to live poultry before their symptoms began.
One healthcare-related cluster was reported among the group: An 85-year-old woman from Zhejiang province who reportedly had no poultry exposure but had shared the same hospital ward with an earlier confirmed case-patient died from H7N9 on Mar 8. Her hospital contact was a Zhejiang province man who had been exposed to live poultry and was also a household contact of a confirmed case. The WHO said human-to-human transmission can't be ruled out and that more virologic information is expected.
May 3 WHO update
Flu vaccination protective against premature birth in Laos
Maternal influenza vaccination improves birth outcomes to the tune of preventing about 1 in 5 preterm births during times of high flu circulation, according to an observational study carried out in Laos and published yesterday in Clinical Infectious Diseases.
The authors, from the US Centers for Disease Control and Prevention and several institutions in Laos, enrolled 5,103 women giving birth at three hospitals in Laos from April 2014 through February 2015. Flu vaccination status was determined by means of vaccine cards, and the proportions of small-for-gestational-age and preterm (<37 weeks gestation) neonates as well as mean birth weight were calculated.
A total of 2,172 (43%) of the women had been vaccinated. Of the 4,854 women who had live births, 10.2% had infants classified as preterm. The proportion born to vaccinated and unvaccinated mothers differed significantly (7.5% vs 12.8%, respectively; P < 0.001; crude relative risk [RR] = 0.58, 95% confidence interval [CI], 0.48-0.71); adjusted RR = 0.70 (95% CI, 0.57-0.87). The protective effect of vaccine remained only among infants born during periods of high influenza activity.
The population prevented fraction was 18.0%. No effect of vaccination was noted on the proportion of infants born small for gestational age (4.7% and 3.8%, P = 0.16, for vaccinated and unvaccinated mothers, respectively) or in mean birth weight.
Laos, which has a high rate of poor birth outcomes that has improved little in the past 10 years, has since 2012 offered free influenza vaccinations to high-risk populations, including pregnant women.
The authors concluded, "Many low and middle income countries have high rates of poor birth outcomes, and in tropical regions these countries may experience year-round influenza virus circulation. Adding influenza vaccine to the current package of antenatal services may be beneficial in countries such as Laos."
May 3 Clin Infect Dis study abstract
Northern Hemisphere flu activity ebbs as it inches up in southern half
The WHO's most recent influenza report shows that flu activity is continuing to decrease in the Northern Hemisphere as it rises slightly in the Southern Hemisphere.
In addition, influenza B has increased in North America, Northern Temperate Asia, Southeast Asia, and in parts of Europe.
In the Southern Hemisphere, particularly in Central and South America, flu activity, influenza-like illness (ILI), and severe acute respiratory infections (SARIs) have slowly been on the rise. Most of the increase can be attributed to 2009 H1N1, the WHO said. Brazil, for instance, has had higher-than-expected levels of H1N1 activity, and Paraguay and Argentina have experienced increased ILI and SARI activities.
Influenza A is also more prevalent in North Africa and West Africa, WHO said, but its activity is still declining. The other regions of Africa have had low levels of flu activity in general.
Unlike last week, all areas in Asia are experiencing low levels in flu activity.
Overall, 46.9% of strains are influenza A and 53.1% are influenza B, according to the WHO. Of these, influenza 2009 H1N1 is the dominant A strain at 84.8%, with H3N2 accounting for 15.2%. The B-Victoria lineage makes up 82.3% of the B strain, with the rest of the isolates of the Yamagata lineage.
May 2 WHO update