Incubation Period for Human Cases of Avian Influenza A (H5N1) Infection in China
Author Information
Author(s): Huai Yang, Xiang Nijuan, Zhou Lei, Feng Luzhao, Peng Zhibin, Chapman Robert S., Uyeki Timothy M., Yu Hongjie
Primary Institution: Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China
Hypothesis
What is the incubation period for human cases of avian influenza A (H5N1) infection in different exposure settings?
Conclusion
The study suggests that the incubation period may be longer after exposure to a wet poultry market than after exposure to sick or dead poultry.
Supporting Evidence
- More than 400 human cases of H5N1 infection have been reported worldwide since 1997.
- Incubation periods were compared using the Wilcoxon rank-sum test.
- Overall median incubation period for those exposed to a wet poultry market was significantly longer than for those exposed to sick or dead poultry.
Takeaway
This study looked at how long it takes for people to get sick after being around sick birds or visiting a market where birds are sold. It found that being in a market might make you sick a bit longer than just being around sick birds.
Methodology
A retrospective descriptive study was conducted on 24 cases of influenza A (H5N1) in China, comparing incubation periods based on exposure settings.
Potential Biases
Proxies for deceased patients may not have known all exposures, and surviving patients may not have recalled all exposures.
Limitations
The study had limitations including potential recall bias from surviving patients and the inability to ascertain exact exposure times.
Participant Demographics
16 participants were exposed to sick or dead poultry (67% lived in rural areas), and 8 participants visited a wet poultry market (88% lived in urban areas).
Statistical Information
P-Value
0.045
Statistical Significance
p=0.045
Digital Object Identifier (DOI)
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