May 20, 2010
Second E coli romaine strain identified
A second Escherichia coli strain that turned up when Ohio laboratory officials were investigating an E coli O145 outbreak linked to romaine lettuce has been identified as O143:H34, a spokeswoman from the state's agriculture department said, according to a report today in the Columbus Dispatch. The US Centers for Disease Control and Prevention (CDC) characterized the second strain, which was found in shredded lettuce marketed by Freshway Foods, based in Sidney, Ohio. Officials had earlier found the E coli O145 outbreak strain in another sample from an unopened package of lettuce distributed by the same company. Public health officials have traced that lettuce to a farm near Yuma, Ariz. Though the second strain can cause illness, an epidemiologist with the Ohio Department of Health said so far no outbreaks have been linked to it. So far 23 confirmed and 7 suspected illnesses in patients from four states have been linked to the E coli O145 outbreak, according to a May 12 CDC update.
May 20 Columbus Dispatch story
May 12 CDC update
Utah explores water source of Campylobacter outbreak
Utah public health officials are still investigating a Campylobacter outbreak that they believe has a link to the Saratoga Springs city water supply, though they have yet to find Campylobacter in water samples, according to a media report and a statement from the Utah County Health Department. So far health officials have confirmed 15 cases. They said they aren't detecting any new cases, but are still receiving notices about people who were previously sick and secondary infections in households. A report from the area's ABC News affiliate said more than 100 illnesses are suspected. A county health official told ABC that they suspect point contamination, and a statement on the health department's Web site said one possibility is well cross-contamination from a resident's pressurized irrigation system in an attempt to provide year-round irrigation. The city shuts its irrigation system off in the winter and recently turned it on.
May 19 Utah County Health Department statement
May 19 ABC News report
Genetic variants linked to infectious-disease susceptibility
Certain variants of a gene involved in signaling between cells in the immune system are associated with increased susceptibility to infectious diseases, a large international team of researchers reported in today's New England Journal of Medicine. The researchers studied a gene called CISH, which controls the signaling of the cytokine interleukin-2, a critical component of the immune system. In a case-control study, the team studied blood samples from 8,402 people to look for an association between CISH variants and susceptibility to tuberculosis, severe malaria, and bacteremia. The volunteers were from Gambia, Hong Kong, Kenya, Malawi, and Vietnam. The scientists found five CISH variants that were significantly associated with increased susceptibility. One particular variant, which accounted for most of the association, increased disease susceptibility by 18%, compared with a person carrying none of the variants. In a press release from the Wellcome Trust, cosponsor of the study, study co-leader Dr. Chiea C. Khor said, "It's not clear from our study why having a reduced level of CISH associates with increased susceptibility to multiple infectious diseases, but it does suggest that CISH is a key regulator of the immune system."
May 20 N Engl J Med article
May 19 Wellcome Trust news release
Headless hemagglutinin may be key to more versatile flu vaccine
Using the decapitated stalk of the influenza hemagglutinin (HA) molecule may be the key to making a flu vaccine that provides protection against a variety of flu viruses, according to a study reported in mBio, a new online-only, open-access journal published by the American Society for Microbiology (ASM). The antigen contained in licensed flu vaccines, which protect against only a narrow range of flu strains, is the highly variable globular head of HA, note the authors, from Mount Sinai School of Medicine in New York City. They constructed a vaccine containing the HA stalk, which is similar among many flu strains, without the globular head. When they used it to vaccinate mice and then exposed them to a normally lethal dose of flu virus, the mice were fully protected from death and partially protected from weight loss. "Through further development and testing, we predict that a single immunization with a headless HA vaccine will offer effective protection through several influenza epidemics," write the authors, led by Dr. Peter Palese.
May 18 mBio report
May 19 ASM press release
Villagers adopt sari water-filtering method
Filtering water with a simple cotton cloth used in sari clothing is a sustainable way to reduce cholera illnesses from drinking pond and river water contaminated with Vibrio cholerae, researchers recently reported in mBio. The study is a follow-up to a trial 5 years ago in Bangladesh that showed filtering household water with one to four layers of sari cloth reduced the incidence of cholera by 48%. In the most recent arm of the study, investigators explored whether the villagers continued filtering their water. They found that 31% of women continued the practice and about 26% of the original control group used some type of filter. Researchers said villagers probably showed their neighbors how to filter the water and that the method is sustainable, though the residents would probably benefit from continued education about appropriate use and benefits. They added that the technique, which can remove up to 99% of the organism from the water, is a cheap and acceptable public health intervention that can be used in endemic areas and locations that face social disruptions.
May 18 mBio study