Flu Scan for Jun 01, 2016

News brief

Large trial in Mali finds maternal flu shots protect newborns

In a large trial in the West African country of Mali, influenza vaccination in pregnant women was found to be more than 60% effective in preventing lab-confirmed flu in newborn infants for the first 4 months of life, according to a report published yesterday in The Lancet Infectious Diseases.

The prospective, randomized controlled trial was conducted at six referral centers and four community health centers in Bamako, Mali's capital, from September 2011 to January 2014. The researchers randomly assigned 4,193 third-trimester pregnant women to receive either a trivalent inactivated flu vaccine (TIV) or a quadrivalent meningococcal vaccine.

The team followed 1,797 infants in the TIV group and 1,793 infants in the control group for 6 months, recording 131 lab-confirmed flu cases among 5,279 flu-like illness episodes. There were 52 first episodes of flu in the TIV group and 77 in the control group.

In the intention-to-treat group—women vaccinated at any time prepartum—vaccine effectiveness in neonates was calculated to be 67.9% (95% confidence interval [CI], 35.1%-85.3%) in the first 4 months of life. VE in the per-protocol group—women vaccinated at least 14 days before giving birth—was 70.2% (95% CI, 35.7 to 87.6%) for the first 4 months.

VE dropped off sharply after 4 months, leading to an overall VE for 6 months of 33.1% (95% CI, 3.7%-53.9%) in the intention-to-treat group and 37.3% (7.6%-57.8%) in the per-protocol group.

Adverse event rates were similar in the treatment and control groups, and no serious adverse events were related to vaccination, although presumed neonatal infections were more common in the flu vaccine group, the researchers said.

"Our trial represents the largest evaluation so far of maternal influenza vaccination as a strategy to prevent influenza in the youngest infants," the authors wrote. "Additionally, it is the first such study to be completed in West Africa, specifically Mali, one of the poorest countries in the world. Demonstrating the efficacy of maternal influenza vaccination in this setting is compelling."

The trial did not show that maternal flu vaccination reduced the incidence of low birth weight, which was consistent with a similar study in South Africa but differed from one in Bangladesh, the researchers said.
May 31 Lancet Infect Dis report

France reports low-path H5N2 avian flu in poultry

French officials have confirmed low-pathogenic H5N2 avian flu detected by heightened surveillance that has been in place after numerous outbreaks in the southwestern part of the country that began in November 2015, according to a report filed with the World Organization for Animal Health (OIE) yesterday.

The virus was detected at a farm in Landes department on Apr 28 after samples were taken on Apr 20. The virus had affected a flock of 10,300 birds, all of which were destroyed to prevent disease spread.

In addition to the H5N2 strain, authorities have previously confirmed H5N1, H5N9, and H5N3 in French poultry.
May 31 OIE report

News Scan for Jun 01, 2016

News brief

WHO declares Guinea to be Ebola-free

The World Health Organization (WHO) today declared that Guinea has passed 42 days since the last patient was declared free of Ebola, officially ending Ebola virus transmission.

Guinea now enters a 90-day period of heightened surveillance to quickly identify any new cases that might arise. "The source of infection in this latest outbreak is likely to have been due to exposure to infected body fluid from an Ebola survivor," the WHO said in a news release. "The risk of additional outbreaks from exposure to infected body fluids of survivors remains."

In the latest outbreak, 7 confirmed and 3 probable cases of Ebola were reported from Mar 17 to Apr 6 in Guinea. In addition, 3 confirmed cases were reported from Apr 1 to 5 in a woman and her children who had traveled from that cluster in Macenta, Guinea, to Monrovia, Liberia.

The entire region could be declared Ebola-free within weeks. The latest case in Liberia—involving the 2-year-old son of the infected woman who traveled from Macenta—was released from treatment on Apr 29, starting that country's 42-day countdown.

West Africa has been declared Ebola-free twice before, only to have new flare-ups surface immediately after the WHO declaration.
Jun 1 WHO news release

CDC says E coli outbreak 'likely' caused by General Mills flour

A 38-case outbreak of Escherichia coli infections in 20 states has been linked to General Mills flour, the Centers for Disease Control and Prevention (CDC) said today.

Yesterday the company recalled 10 million pounds of its flour "out of an abundance of caution," saying no E coli has been detected in the flour or at its manufacturing plant.

Of 21 patients interviewed, 16 (76%) reported that they or someone in their household had used flour in the week before they fell ill. Nine of 22 patients (41%) reported eating raw homemade dough or batter, while 3 reported eating or playing with raw dough at a restaurant. Twelve of 22 people, or 55%, specified Gold Medal brand flour, which is made by General Mills.

"Collaborative investigative efforts indicate that flour produced at the General Mills facility in Kansas City, Missouri, is a likely source of this outbreak," the CDC said today.

Ten patients required hospitalization, but none developed hemolytic uremic syndrome, a type of kidney failure associated with foodborne disease, and none have died. Illness-onset dates range from Dec 21, 2015, to May 3, and patients vary in age from 1 to 95 years. About half are children, as the patients' median age is 18.

Colorado, Illinois, and Michigan reported the most cases, at four, while Minnesota has had four. The CDC warned consumers not to eat raw flour of any brand because of the risk of infection.
Jun 1 CDC statement
May 31 CIDRAP News story "Multistate E coli outbreak prompts General Mills flour recall"

Texas reports first local chikungunya case; Florida confirms dengue illness

Texas has reported its first locally acquired case of chikungunya, while Florida officials have confirmed that state's first local case of dengue this year, in Key West. Both diseases are transmitted by the bite of Aedes mosquitoes.

The Texas Department of State Health Services (DSHS) said yesterday that a resident of Cameron County at the southernmost tip of the state contracted chikungunya in November 2015 without traveling. A lab test came back positive for the disease in January, but results were not reported to the local health department till April. The CDC confirmed the disease last week.

The first locally acquired chikungunya cases in the United States were confirmed in Florida in July 2014. The disease has affected almost 2 million people in the Americas since it first appeared in December 2013.
May 31 Texas DSHS press release

Florida's dengue case involves a visitor to Key West who has returned to his or her home state and is expected to make a full recovery, the Florida Department of Health (FDH) reported today.

"All indications are that this infection was locally acquired in Key West," the FDH said in a news release. The island has not had a dengue case since October 2010, the agency said.

Last year the state reported 1 locally acquired dengue case, in December, compared with 6 in 2014 and 23 in 2013.
Jun 1 FDH news release

Study: Wolbachia-infected mosquitoes less likely to carry malaria

A strain of Wolbachia bacteria that exists in Anopheles mosquitoes in Burkina Faso seems negatively related to the prevalence of malaria parasites in the insects, suggesting that the bacteria may have important effects on malaria transmission in sub-Saharan African, according to a report yesterday in Nature Communications.

Wolbachia bacteria are natural denizens of the gut in about 60% of all insects, and they are being eyed as possible weapons against the spread of mosquito-borne viruses, such as Zika and dengue, according to previous reports. The authors said it was previously believed that Wolbachia could not infect Anopheles mosquitoes, but they recently identified stable Wolbachia infections in A gambiae and A coluzzii in Burkina Faso.

The researchers analyzed 221 female A coluzzii collected from houses in one village and found that 116 (52.5%) were infected with a Wolbachia strain that they have named wAnga. Plasmodium (malaria) infections were found in 12 (5.4%) of the insects, only 1 of which was also infected with Wolbachia.

"This highly significant reduction—over 90%—suggests that wAnga may interfere with Plasmodium development in the mosquito vector, as shown in artificial Anopheles–Wolbachia combinations," the authors wrote.

Using a mathematical model incorporating this finding, the researchers projected that Wolbachia in Anopheles mosquitoes may reduce malaria prevalence in human populations. "These data suggest that Wolbachia may be an important player in malaria transmission dynamics in Sub-Saharan Africa," they wrote.

They said their findings need confirmation with further studies involving other Anopheles species, larger samples, and more locations.
May 31 Nat Commun report