Sunday, March 30, 2014

Details of an A(H7N9) Family Cluster in February from Dongyang, Jinhua, Zhejiang Province

Although more than 400 people have been infected with A(H7N9), reports of clusters of cases are rare. Based on publicly available information, only 14 H7N9 human cluster have been reported. Most of these clusters are family or neighborhood clusters of 2-3 individuals. These clusters are almost never officially reported by the Chinese public health authorities.

The most recent reported cluster is family cluster of two sisters from Dongyang in Zhejiang Province. An extended media report details the identifications and treatment of 3 children infected with H7N9 from Dongyang.[1] Computer translation of the article reports that three infected children with ages ranging from 2-8 were identified over the course of four days in February, 2014.[2]  Two of the children were sisters from one family with different onset dates. The two children apparently observed, but did not participate, in the slaughter of several chickens by one of the parents. The report is not clear whether the third child from the same city, surname Ren, is related to or had contact with the two sisters.

The three children hospitalized in Dongyang are reported to have recovered and been released from the hospital between 4 and 12 days after admission. The article mentions that one health care worker treating the patient also had a fever, but apparently was not infected with H7N9. Although the two girls are a family cluster, the infections may have resulted from exposure to a common source rather than human to human transmission. This small family cluster is at least the 14th H7N9 cluster reported since March of 2013.

Hat tip to Pathfinder at

Wednesday, March 19, 2014

Is Taihu Lake, Zhejiang Province the Geographic Source of the H7N9 Virus? (Map)

An important ahead-of-print article on the possible origins of the H7N9 virus has been published by researchers from the Zhejiang Provincial Center for Disease Control and Prevention in Hangzhou, China in the journal Zoonoses and Public Health. The researchers conducted genetic analyses of environment samples, human samples, and domestic and wild avian samples of the H7N9 virus from several provinces in the eastern portion of the People‘s Republic of China (PRC).

The article, entitled Hypothesis On The Source, Transmission and Characteristics of Infection of Avian Influenza A (H7N9) Virus – Based On Analysis of Field Epidemiological Investigation and Gene Sequence Analysis is behind a John Wiley & Sons paywall. However, within the freely available abstract, these Chinese researchers propose that the H7N9 virus now infecting people and domestic poultry originated with migratory bird populations in the Taihu Lake area of Zhejiang Province.

Their analysis suggests that . . . avian viruses carried by waterfowl combined with the virus carried by migratory birds, giving rise to avian influenza virus H7N9, which is highly pathogenic to humans. It is possible that the virus was transmitted by local wildfowl to domestic poultry and then to humans, or spread further by means of trading in wholesale poultry markets.

The authors speculate that . . . the infection source in the triangular area around Taihu Lake still remains. They also forecast that . . . The H7N9 epidemic will probably hit the area later in the year and next spring when the migratory birds return and may even spread to other areas.

This is a sobering forecast of future outbreaks of H7N9. Researchers from Zhejiang Province ought to know. More than 1/3 of all human H7N9 cases have been reported from Zhejiang Province.



Sunday, March 9, 2014

Foldscope: An origami microscope that will revolutionize disease surveillance

In a paper published in ArXiv entitled Foldscope: Origami-based paper microscope, Manu Prakash (Assistant Professor of Bioengineering at Stanford) and colleagues detail an approach for creating low cost brightfield, darkfield, and fluorescence microscopes that could revolution field testing for infectious diseases. These inexpensive microscopes (less than one dollar each) could be printed by the thousands and could be widely used as a medical screening tool in the developing world.

“Here we describe an ultra-low-cost origami-based approach for large-scale manufacturing of microscopes, specifically demonstrating brightfield, darkfield, and fluorescence microscopes. Merging principles of optical design with origami enables high-volume fabrication of microscopes from 2D media. Flexure mechanisms created via folding enable a flat compact design. Structural loops in folded paper provide kinematic constraints as a means for passive self-alignment. This light, rugged instrument can survive harsh field conditions while providing a diversity of imaging capabilities, thus serving wide-ranging applications for cost-effective, portable microscopes in science and education.”

Link: arXiv:1403.1211 [physics.optics]

See Manu Prakash’s 2012 TED talk: A 50-cent microscope that folds like origami

Monday, March 3, 2014

Map: Geographic Distribution of Human A(H7N9) Cases in Eastern Asia, Second Wave, November 1, 2013 to March 3, 2014

About 230 human cases of H7N9 have been reported during the second wave of this disease outbreak since November 1, 2013.  The map below depicts the geographic distribution of these cases by second level administrative units (counties) in the People's Republic of China (China), and by level 1 (state) in Malaysia.  The case in Malaysia was imported from China, however, cases have occurred in latitudes ranging from 21 to 43 degrees North.  The map is current through March 3, 2014.