Study finds wider spread, longer persistence in 4th wave of H7N9 cases
The fourth wave of H7N9 avian flu infections in China (from September 2015 through August 2016) saw continued geographic spread of the virus, a longer epidemic period, and a higher proportion of case-patients living in rural areas compared with the first three waves, a report today in Morbidity and Mortality Weekly Report (MMWR) noted.
Chinese researchers analyzed epidemiology and virology data for all 775 lab-confirmed H7N9 cases in the country since March 2013. The number of cases per wave was 134, 304, 219, and 118, respectively.
The investigators found no difference between the fourth wave and the earlier waves in age and sex distribution, exposure history, and proportion of cases tied to a cluster. Likewise, the genetic markers of mammalian adaptation and antiviral resistance remained similar across each wave, and viruses from the fourth epidemic remained antigenically well matched to current candidate vaccine viruses.
The researchers found, however, that the fourth wave featured a greater percentage of patients living in rural areas, continued geographic spread of the virus, and a longer epidemic period. They also reported no increase in human-to-human spread of the virus.
The authors conclude, "There is a need for a national containment-control-eradication program in poultry, in addition to effective A(H7N9) virus surveillance and continued risk assessment among humans and poultry in China and neighboring countries."
Dec 16 MMWR report
US officials report better than 99% success in Ebola monitoring
US authorities achieved a greater than 99% success rate in monitoring incoming travelers in 2014 and 2015 during the height of West Africa's Ebola outbreak, according to a separate report today in MMWR.
Of 29,789 people monitored from Nov 3, 2014, through Dec 27, 2015, 442 (1.4%) were classified as at some risk to high risk (mostly health workers who treated Ebola patients), 28,759 (97.0%) were low-risk travelers, and 598 (2.0%) were low-risk healthcare workers.
The authors said more than 99% completed 21-day monitoring with no loss to follow-up exceeding 2 days but did not specify the exact number of patients who completed the monitoring. They noted, however, that a median of three people for whom monitoring was indicated could not be contacted each week, and, among all those contacted for monitoring, a median of five per week had gaps in monitoring that were greater than 2 days.
In a given week, a median of 1,680 people were monitored, and 53% of those monitored were reported in just 5 of 60 jurisdictions. The number of people monitored weekly decreased 46% from a peak in mid-May 2015 to mid-June 2015. Among 796 symptomatic people in the low-risk and some-risk categories, 104 (13%) were tested for Ebola during monitoring, but none tested positive.
Dec 16 MMWR report
Canadian researchers describe patient with multiple KPE isolates
Canadian researchers are reporting a case of a single patient with multiple variants of Klebsiella pneumoniae carbapenemase (KPC)-producing bacteria.
In a letter today in the New England Journal of Medicine, the researchers report on the case of an 82-year-old man with heart failure and chronic obstructive pulmonary disease who was admitted to the same hospital 21 times between 2011 and 2015. The patient was most often grouped with other patients colonized or infected with KPC-producing Enterobacteriaceae (KPE) and received numerous courses of antibiotics during that time.
The researchers were able to identify 14 KPE isolates in the patient and sequence the genome of 9 of them. Three species were identified (K pneumoniae, K oxytoca, and Escherichia coli), and all 9 isolates were found to be carrying the KPC-3 gene on plasmids. Furthermore, several of the isolates appeared to be linked to each other by means of plasmid transfer. It's unclear, however, whether the multiple isolates arose from the spread of the resistance element within the host, from exposure to other KPE-colonized patients, or both.
The authors write that while there have been previous reports of multiple KPE colonizations or infections in a single patient, their study shows the evolution and diversity of KPE within a single patient over several years.
Dec 15 N Engl J Med letter