Northeastern US sees late-season flu spike
Flu activity in the United States continued to decline last week, but some indicators were up slightly, reflecting a late-season uptick in the Northeast, according to the US Centers for Disease Control and Prevention (CDC).
As a whole, the percentage of respiratory specimens that tested positive for flu was up slightly from 13.4% to 14.5%, but the percentage of clinic visits for influenza-like (ILI) illness fell a bit, from 1.6% to 1.5%. Two of the CDC's 10 regions were well above their baselines for clinic ILI visits, and both encompass northeastern states.
An analysis of strains that tested positive for flu shows that 55.4% were influenza B and that for subtyped influenza A strains, H3N2 was much more common—a change from earlier in the season when the 2009 H1N1 virus was dominant. Increasing numbers of influenza B and H3N2 viruses seem to be fueling the increased activity in northeastern states, according to media and official reports.
Six states reported geographically widespread flu cases, up from five the week before. The states are Connecticut, Delaware, Maine, New Jersey, New York, and Rhode Island. The percentage of overall deaths from pneumonia and flu was below the seasonal baseline, and the CDC received one more pediatric flu death report, from influenza B, which raised the season's total to 86.
Meanwhile, the Public Health Agency of Canada (PHAC) said yesterday that the country's flu activity was at expected levels for this time of year, with sustained activity from influenza B, especially in Ontario, which has seen a marked increase, and some western provinces. It said influenza B is having a greater impact on seniors and young people ages 5 to 19, a change from earlier in the season when the 2009 H1N1 virus mainly affected adults aged 20 to 64.
In Europe, flu levels continued to drop, but some countries are still seeing virus circulation, the European Centre for Disease Prevention and Control (ECDC) said today. Thirteen percent of respiratory samples were positive for flu, half the previous week's proportion. Three countries reported widespread or regional flu activity: Croatia, Greece, and the Netherlands.
Apr 18 CDC FluView report
Apr 17 PHAC FluWatch report
Apr 18 ECDC weekly flu surveillance report
China reports 2 H7N9 cases, 1 fatal
Two new H7N9 avian flu cases, one of them fatal, were reported by two of China's provinces today. Health officials in Anhui province announced that a 70-year-old man had died of the infection, according to a post today from FluTrackers, an online infectious disease message board.
The man, from Tongling city, died Apr 14, and H7N9 was confirmed 2 days later, according to a translated news story. Anhui has had 13 previous H7N9 cases.
Also, Jiangsu province reported an infection in a 34-year-old man who is hospitalized in Wuxi in critical condition, according to a health department statement translated and posted by FluTrackers.
The cases and fatality push the outbreak's overall total to 425 and the unofficial death count to 128, according to a FluTrackers case list. So far 288 cases have been reported in the outbreak's second wave, which began in October, compared with 136 during the first wave last spring.
Apr 18 FluTrackers post
FluTrackers human H7N9 case list
Researchers develop ILI tracker using Wikipedia data
It may be possible to track US levels of influenza-like illness (ILI) using Wikipedia traffic, two Harvard experts said in a study published yesterday in PLoS Computational Biology.
The researchers calculated daily hits on ILI-related Wikipedia articles from December 2007 to August 2013 and developed a Poisson model that they said performed well at predicting actual ILI levels in severe flu seasons and the 2009 H1N1 pandemic, which received much media attention.
They said the model estimated ILI levels up to 2 weeks ahead of data from the Centers for Disease Control and Prevention (CDC). The scientists reported an absolute average difference of 0.27% over 294 weeks of analysis between their model's and the CDC's estimates.
The authors said in a press release from the Public Library of Sciences (PLoS) that they hope their model "can harness publicly available data to help people get accurate, near-realtime information about the level of disease burden in the population."
They conclude in the study, "With further study, this method could potentially be implemented for continuous monitoring of ILI activity in the US and to provide support for traditional influenza surveillance tools."
Their study comes 2 months after Nature reported that Google Flu Trends, a similar Internet-based tracking system, drastically overestimated peak flu levels in the 2013-14 season.
Apr 17 PLoS Comput Biol study
Apr 17 PLoS press release
Feb 14 Nature News report
Guinea Ebola outbreaks sickens, kills more
Five new Ebola virus disease (EVD) cases have been reported by Guinea's health ministry over the past 2 days, boosting the country's outbreak total to 202, according to a brief update yesterday from the World Health Organization (WHO) Regional Office for Africa. Three more deaths were reported, lifting the fatality count to 125. So far 108 cases have been lab-confirmed.
No new illnesses or deaths have been reported in Liberia, the only other West African nation to have EVD cases, keeping those totals at 27 infections, 13 of them fatal. So far six of the country's cases have been lab-confirmed.
The EVD outbreak affecting the two countries is West Africa's first, and scientists who analyzed gene sequences obtained from some of the patients sickened in the early part of the outbreak found that it is a unique strain, which indicates that the outbreak isn't related to EVD events in other parts of Africa.
Apr 17 WHO report