WHO declares West Africa free of Ebola transmission
Today the World Health Organization (WHO) declared Liberia free of Ebola transmission—meaning the last patient in the country tested negative for a second time 42 days ago—a step that marks the third time West Africa has been declared free of Ebola after its massive outbreak in 2014 and 2015.
The previous two times the WHO declared the region free of Ebola transmission, in January and March, flare-ups occurred within a matter of hours, restarting the process.
Liberia now enters a 90-day period of heightened surveillance, the WHO said in a statement. The agency has declared an end to Ebola transmission in the country three previous times, starting on May 9, 2015. The most recent flare-up involved a woman and her two children, one of whom tested negative for the virus for a second time two 21-day incubation periods ago, thus becoming the last known case-patient in the region.
Sierra Leone declared an end to Ebola transmission on Mar 17, and Guinea followed on Jun 1.
"WHO commends Liberia's government and people on their effective response to this recent re-emergence of Ebola," said Alex Gasasira, MBChB, MPH, WHO representative in Liberia. "WHO will continue to support Liberia in its effort to prevent, detect, and respond to suspected cases."
The agency cautioned that the three countries must remain vigilant for new infections, adding that the risk of additional outbreaks from exposure to infected body fluids of survivors remains.
Jun 9 WHO statement
Mar 17 CIDRAP News story noting previous WHO Ebola declaration
Saudi Arabia reports new camel-associated MERS case
Saudi Arabia's Ministry of Health (MOH) today reported a MERS infection in a patient from the northwestern part of the country.
The MERS-CoV (Middle East respiratory syndrome coronavirus) case involves a 59-year-old Saudi man from Tabuk, a city near Saudi Arabia's border with Jordan. He is hospitalized in stable condition and is not a healthcare worker. The MOH said that the source of his infection as "primary (contact with camels)."
The country had gone 5 days without a MERS case; before that, it experienced an 18-day stretch with no cases.
The man's illness raises Saudi Arabia's MERS total since 2012 to 1,385 cases, 592 of them fatal. Three people continue to receive treatment for their infections, the MOH said.
Jun 9 MOH update
Study: Genetic link found between Black Death and modern plague
Genetic evidence points to travel of Yersinia pestis into Asia following four centuries of European outbreaks, demonstrating a link between ancient pandemic plague strains and modern epidemics, according to a study yesterday in Cell Host & Microbe.
Researchers led by those at the Max Planck Institute for the Science of Human History analyzed three Y pestis DNA samples extracted from individuals buried in Barcelona, Spain; Ellwangen, Germany; and Bolgar City, Russia; from the 14th to 17th centuries. Samples were compared with a database of 148 ancient and modern strains to fill in gaps on Y pestis's phylogenetic tree.
The strain from Barcelona, one of the main European entry points for the massively lethal plague epidemic known as the "Black Death" in the 1300s, was similar to three London strains from the same period. A single bacterial lineage was responsible for recurring European outbreaks until the disease's sudden disappearance from the continent in the late 1700s, the authors said. The lineage then gave rise to a branch with no descendants that caused outbreaks in Ellwangen, Germany, and Marseilles, France.
DNA from Bolgar City showed similarities both to the London strain and to modern Y pestis samples, suggesting that one bacterial lineage traveled from Europe to Asia after the Black Death, caused the last-known plague pandemic in China in the late 1800s, and achieved subsequent global spread during modern epidemics.
The study provides evidence that modern plague outbreaks are genetically linked to the bacterium that caused the Black Death in Europe, the authors wrote. They add that more evidence is needed to establish why outbreaks of Y pestis differ significantly in mortality and transmission and the genetic diversity of bacterial strains outside China.
Jun 8 Cell Host Microb study
Report details 2012 cow-related outbreak of cutaneous anthrax in China
Nearly half of the individuals exposed in 2012 to a slaughtered sick cow in a region of China where anthrax is not endemic developed cutaneous anthrax within 8 days of exposure, with the major risk factors being contact with the animal's blood and the presence of skin damage in those exposed, says a retrospective cohort study published today in Epidemiology & Infection.
A total of 17 people in the eastern Chinese province of Jiangsu were exposed on Jul 25, 2012, to the sick cow, which had arrived from northeast China for slaughter several days earlier, or its products. The index case was a butcher who cut his finger on a bone from the animal during slaughter; no personal protective equipment was in use. Upon questioning, he identified others involved in the slaughter as well as in the handling of such animal products as skin, meat, blood, hide, and bones.
Of the group, 8 were found to have become ill with symptoms of cutaneous anthrax between 1 and 8 days after exposure (mean, 2 days). All patients recovered. Three main genes of Bacillus anthracis were common to both the animal and the case-patients.
Among potential risk factors for infection evaluated by the authors, just two—contact with blood from the sick cow (relative risk [RR]=2.5; 95% confidence interval [CI], 1.3-4.6) and the presence of skin damage before exposure (RR=2.8; 95% CI, 1.4-5.7), contributed significantly to infection.
The authors say their findings highlight the need for enhanced quarantine of imported livestock or their products from anthrax-endemic areas; the importance of educating livestock owners, butchers, and other high-risk individuals about the risks of slaughtering sick animals; the desirability of using personal protective equipment; and the advisability of training for primary healthcare personnel even in areas in which anthrax cases are not typical.
Jun 9 Epidemiol Infectabstract