tetano
Editor, Senior Moderator
J Infect Dis. 2012 Jul 24. [Epub ahead of print]
Seasonality, timing, and climate drivers of influenza activity worldwide.
Azziz Baumgartner E, Dao C, Nasreen S, Bhuiyan MU, Mah-E-Muneer S, Al Mamun A, Sharker MA, Zaman RU, Cheng PY, Klimov AI, Widdowson MA, Uyeki T, Luby SP, Mounts A, Bresee J.
Source
Influenza Division, Centers for Disease Control and Prevention, USA.
Abstract
Background. Although, influenza is a vaccine-preventable disease which annually causes substantial disease burden, data on virus activity in tropical countries are limited. We analyzed publicly available influenza data to better understand the global circulation of influenza viruses.Method. We reviewed open-source laboratory-confirmed influenza surveillance data. For each country we abstracted data on the percent of samples testing positive for influenza each epidemiologic week from the annual number of samples testing positive for influenza. The start of influenza season was defined as the first week when the proportion of samples that tested positive remained above the annual mean. We assessed the relationship between percent of samples testing positive and average monthly temperature using regression models.Findings. We identified data on laboratory-confirmed influenza virus infection from 85 countries. More than one influenza epidemic period per year was more common in tropical countries (41%) than temperate countries (15%). Year-round activity (i.e., influenza virus identified each week having ≥10 specimens submitted) occurred in 3 (7%) of 43 temperate, one (17%) of six subtropical, and 11 (37%) of 30 tropical countries with available data (p=0.006). Percent positivity was associated with low temperature (p=0.001).Interpretation. Annual influenza epidemics occur in consistent temporal patterns depending upon climate.
PMID:
22829641
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/22829641
Seasonality, timing, and climate drivers of influenza activity worldwide.
Azziz Baumgartner E, Dao C, Nasreen S, Bhuiyan MU, Mah-E-Muneer S, Al Mamun A, Sharker MA, Zaman RU, Cheng PY, Klimov AI, Widdowson MA, Uyeki T, Luby SP, Mounts A, Bresee J.
Source
Influenza Division, Centers for Disease Control and Prevention, USA.
Abstract
Background. Although, influenza is a vaccine-preventable disease which annually causes substantial disease burden, data on virus activity in tropical countries are limited. We analyzed publicly available influenza data to better understand the global circulation of influenza viruses.Method. We reviewed open-source laboratory-confirmed influenza surveillance data. For each country we abstracted data on the percent of samples testing positive for influenza each epidemiologic week from the annual number of samples testing positive for influenza. The start of influenza season was defined as the first week when the proportion of samples that tested positive remained above the annual mean. We assessed the relationship between percent of samples testing positive and average monthly temperature using regression models.Findings. We identified data on laboratory-confirmed influenza virus infection from 85 countries. More than one influenza epidemic period per year was more common in tropical countries (41%) than temperate countries (15%). Year-round activity (i.e., influenza virus identified each week having ≥10 specimens submitted) occurred in 3 (7%) of 43 temperate, one (17%) of six subtropical, and 11 (37%) of 30 tropical countries with available data (p=0.006). Percent positivity was associated with low temperature (p=0.001).Interpretation. Annual influenza epidemics occur in consistent temporal patterns depending upon climate.
PMID:
22829641
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/22829641