US report is cautious on climate change impact on infectious diseases
A draft White House report on the impact of climate change on human health takes a cautious tone regarding the possible effects of a warming climate on the prevalence of infectious diseases.
The report, "The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment," was released by the US Global Climate Change Research Program yesterday. The program has invited public comments on the report and is also submitting it to the National Academy of Sciences for peer review.
The report says climate is just one of many factors that affect the distribution of diseases caused by pathogens carried by vectors such as mosquitoes, fleas, and ticks. Other factors are land use, socioeconomic and cultural variables, pest control, access to health care, and human responses to disease risk.
"Whether climate change in the U.S. will increase the chances of domestically acquiring diseases such as dengue fever is uncertain, due to vector-control efforts and lifestyle factors, such as time spent indoors, that reduce human-insect contact," the report states.
"There is a need for finer-scale, long-term studies to help quantify the relationships among weather variables, vector range, and vector-borne pathogen occurrence, the consequences of shifting distributions of vectors and pathogens, and the impacts on human behavior. Enhanced vector surveillance and human disease tracking are needed to address these concerns," the document says.
It observes that food- and water-borne diarrheal diseases, including salmonellosis and campylobacteriosis, are more common when temperatures are higher, but that patterns differ by place and pathogen. Increases in such diseases are also associated with both unusually high and low precipitation.
"Risks of waterborne illness and beach closures resulting from changes in the magnitude of recent precipitation (within the past 24 hours) and in lake temperature are expected to increase in the Great Lakes region due to projected climate change," the report states.
Climate change report landing page
WHO: Global flu continues to taper
Influenza activity continued to decrease globally, except in some tropical nations, but remained above the seasonal threshold in the Northern Hemisphere, the World Health Organization (WHO) said in an update yesterday. It reported on data through Mar 22, which is about a week behind what individual nations are reporting.
Activity decreased in North America and Europe but remains slightly above the seasonal threshold in North America, the WHO said. The proportion of viruses testing positive for influenza B continued to increase in both regions, which is typical late in the season.
Flu activity likewise decreased in northern Africa, the Middle East, and western Asia, with the exception of Turkey, where it increased as 2009 H1N1 and influenza B co-circulated. The H1N1 strain predominated in northern Africa and the Middle East. The only country in temperate east Asia seeing an increase in flu was South Korea.
In the tropics, reports of flulike illness increased in Colombia, Ecuador, Jamaica, and Puerto Rico, while influenza activity remained high and 2009 H1N1 predominated in India and Bhutan.
Just a little over half of influenza viruses from sentinel labs were influenza strain (51.1%), with the rest influenza B. Almost all "B" strains belonged to the Yamagata lineage, which is the strain in the trivalent (three-strain) vaccine.
Apr 6 WHO update
Officials note 8 H7N9 deaths in Zhejiang province
Officials in China's Zhejiang province have quietly posted notice of 10 fatal H7N9 avian flu cases in March, 8 of which were not previously reported, according to a post today by FluTrackers, an infectious disease news message board.
The data were included in a table on the Zhejiang Provincial Health and Family Planning Commission Web site that listed 43 fatalities involving notifiable infectious diseases. FluTrackers was able to identify that 2 of the 10 were already confirmed in late March. No details were provided on the new fatal cases.
FAO: 7 recent H5N1 cases in Egypt
Egypt has had seven recent cases of H5N1 avian flu in people, the United Nations Food and Agriculture Organization (FAO) said today, according to FluTrackers.
Two cases each were confirmed in Sohag and Sharqia governorates, while Giza, Qaiyubia, and Kafr el-Sheikh each had one. All cases were reported on Apr 6, the FAO said, with "observation" dates ranging from Mar 20 to Mar 27 and dates of test results varying from Mar 29 to Apr 4. No other details were provided, including patient age, sex, disease severity, and possible poultry contact.