News Scan for Apr 09, 2015

Cholera on Hispaniola
;
Measles in the Philippines
;
More ice cream-linked Listeria
;
H7N9 transmission in mammals

Cholera cases in Haiti, Dominican Republic continue to top 2014

Haiti and the Dominican Republic continue to report cholera cases in early 2015 well above levels seen during the same period last year, the Pan American Health Organization (PAHO) reported late last week.

From the first of the year through mid-March, Haiti had 10,328 cases, 8,124 hospitalizations (79% hospitalization rate), and 106 deaths. That compares with 7,225 cases, 5,794 hospitalizations, and 86 deaths reported by PAHO a month ago. The agency said 2015 levels are on par with the same period in 2012.

The current epidemic in Haiti, which PAHO said is now in an endemic pattern, began in October 2010. Over that period the country has logged 734,983 cases, 419,087 hospitalizations, and 8,761 deaths.

Cholera impact in the Dominican Republic through mid-March reached 185 suspected cases and 9 deaths, more than double the number in the same period in 2014. The number is up from 99 cases and 6 deaths reported a month ago.

For all of last year the country reported 597 suspected cholera cases, including 10 deaths, which was a 70% reduction in cases and a 76% reduction in deaths from 2013, PAHO said. Since the outbreak began in November 2010, the Dominican Republic has had 32,257 cholera cases and 487 deaths.
Apr 3 PAHO report

 

Report says Philippines needs to bolster efforts to oust measles

Progress toward eliminating measles in the Philippines has faltered in the past few years, and greater efforts are needed to push the disease out of the country and surrounding regions, according to an article today in Morbidity and Mortality Weekly Report (MMWR).

In 1998 the Philippines set a national goal of eliminating measles by 2008, the report says. Coverage with the first dose of measles-containing vaccine (MCV) as estimated by the World Health Organization (WHO) increased from 80% in 1998 to 90% in 2013. Routine vaccination with a second dose of MCV began in 2010, and second-dose coverage rose to 53% by 2013.

After nationwide supplemental immunization activities (SIAs) in 1998 and 2004, the Philippines achieved historic lows in measles cases in 2006, the article says. But despite more SIAs in 2007 and 2011, cases and incidence generally increased from 2007 to 2012. In 2013 and 2014, large outbreaks affected infants, children, and young adults. Contributing factors in the outbreaks included first-dose vaccine coverage of less than 95%, low second-dose coverage, and delayed and patchy outbreak-response immunization efforts.

The article also notes that the WHO's Western Pacific Region (WPR) set a goal of eliminating measles by 2012. "For the goal of measles elimination in WPR to be achieved, sustained investments are required in the Philippines to strengthen health systems, implement the recommended elimination strategies, and develop additional strategies to identify and reduce measles susceptibility in specific geographic areas and older age groups," it states.
Apr 10 MMWR article

 

CDC: 3 Texas cases increase ice cream Listeria outbreak to 8

An outbreak of listeriosis linked to Blue Bell ice cream grew to eight cases as three cases were confirmed in Texas, the Centers for Disease Control and Prevention (CDC) said in an update yesterday.

Two of the newly reported cases date back to the spring of 2011, while the other is from last October, the CDC said. The other five cases—three of which proved fatal—were all in Kansas and occurred from January 2014 to this January.

Isolates from four of the Kansas patients as well as from all three Texas patients were nearly identical to strains isolated from a Blue Bell Creameries plant in Broken Arrow, Okla., that was shut down by the company on Apr 3.

In addition, the CDC has identified three additional patients who had listeriosis from 2010 through 2012. Their isolates showed a similar pattern to those from outbreak patients, so the agency is doing follow-up testing to determine whether their illnesses are also related.

Blue Bell has recalled all products made on the same production line in the Oklahoma plant from Feb 12 to Mar 27, 2015.
Apr 8 CDC update

 

Study: H7N9 adaptation in mammals may limit transmission

The genetic diversity of H7N9 avian flu viruses that infect ferrets—said to be a good model for human infection—is very limited, which might signify a "genetic bottleneck" to adaptation in mammals, according to a study yesterday in Nature Communications.

Researchers from St. Jude Children's Research Hospital in Memphis, Tenn., evaluated the replication efficiency, genetic diversification, and host adaptation of H7N9 virus after they inoculated chickens and ferrets and during ferret-to-ferret transmission. They showed that chickens, a natural H7N9 host, remained asymptomatic and that infection generated high genetic diversity.

They found genetic diversity in infected ferrets, in contrast, "tightly restricted," which they said limited further adaptation to a fully transmissible form. The investigators also noted that airborne transmission in ferrets was accompanied by mutations in the PB1, NP, and neuraminidase (NA) genes that reduce viral polymerase and NA activity—an indication of decreased potential for transmission.

The authors wrote, "Therefore, while A(H7N9) virus can infect mammals, further adaptation appears to incur a fitness cost."

They concluded, "This previously unrecognized biological mechanism limiting species jumps provides a measure of adaptive potential and may serve as a risk assessment tool for pandemic preparedness."
Apr 8 Nature Comm study

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