Aug 30, 2011
Black Death bacterium highly similar to modern-day plague pathogen
A team of international researchers has confirmed by DNA sequencing that Yersinia pestis, the bacterium that causes modern-day plague, was the pathogen responsible for the Black Death, which killed about a third of Europe's population in the 14th Century. The researchers discovered the ancient strain to be quite similar but not entirely identical to modern strains, according to their study in Proceeding of the National Academy of Sciences yesterday. They concluded, however, that the small differences they found would not explain the dramatic differences in the manifestations of ancient versus modern plague, including much higher death rates in the ancient form. Using DNA extracted from the bones and teeth of bodies from a London mass burial site used from 1348 through 1350 for plague victims, they were able to sequence about 99% of one of the bacterium's three plasmids, which house some of its genetic material. From sequencing that PCP1 plasmid they not only confirmed the 14th-Century pathogen to be Y pestis, as previous studies have reported, but they found it be relatively unchanged for almost 700 years. They wrote, "We feel confident that the PCP1 plasmid presented here did not contribute to the purported differences between ancient and modern forms of the disease." The minor variants that they identified have not been reported before, they said, and the variant that they sequenced "may no longer exist." In a New York Times story yesterday, plague expert Mark Achtman from University College Cork in Ireland said that much more DNA from the ancient strain needs to be sequenced, as the plasmid portion contains only a fraction of the organism's entire genome. The study authors said they plan to do just that.
Aug 29 Proc Natl Acad Sci study
Aug 29 New York Times article
Iowa news investigation finds gaps in egg safety system
An investigation by the Des Moines Register has revealed gaps in state and federal egg safety systems, despite new federal regulations designed to reduce Salmonella in shell eggs, according to an Aug 27 report. The paper's review of records it obtained under the Freedom of Information Act found that some of the state's biggest egg producers aren't meeting minimum federal standards designed to reduce the risk of Salmonella enteritidis contamination. For example, the investigation found that egg farm inspections are announced days in advance and that egg producers aren't required to tell government inspectors or state officials when tests for Salmonella are positive. Inspectors at one farm, which was visited by US Food and Drug Administration (FDA) inspectors in May for the first time, had "immediate concerns" about its written Salmonella prevention plan. In other instances, the Register found that FDA redacted some findings, such as the size of rodent infestations and brand names under which the eggs are sold. FDA officials did not comment for the story. Iowa, the nation's top egg producer, has had no egg recalls since the massive one in 2010 that sickened nearly 2,000 people in multiple states. New federal egg safety rules started taking effect in 2010 for the largest farms, those that have 50,000 or more laying hens.
Study: Rotavirus vaccine has benefited unvaccinated groups
The introduction of the rotavirus vaccine in 2006 led to decreased hospitalizations for rotavirus and unspecified gastroenteritis not only in young children but also in older children and adults, according to a report by researchers from the Centers for Disease Control and Prevention (CDC) published in the Journal of Infectious Diseases (JID). Rotavirus caused 58,000 to 70,000 pediatric hospitalizations per year before routine rotavirus vaccination of US infants began in 2006, the Infectious Diseases Society of America (IDSA) said in a press release. The CDC researchers used the National Inpatient Sample, a database on inpatient stays at more than 1,000 hospitals in 42 states, to find data on rotavirus and cause-unspecified gastroenteritis hospital discharges from 2000 through 2008. They found that both types of hospitalizations were significantly reduced in 2008 in 3- to 24-year-olds, who were not eligible for vaccination, with the greatest reductions in March, the peak month for rotavirus in the pre-vaccine era. Also in March, the team found significant reductions in rotavirus admissions for patients 25 and older and in admissions for severe diarrhea in the elderly. "We speculate that vaccinating infants curtailed rotavirus transmission in the community, resulting in fewer infections across the entire population," first author Dr. Joseph Lopman said in the press release. About 10,000 hospitalizations of children 5 and older were prevented in 2008, the team estimated.
Aug 30 JID report
Aug 30 IDSA press release