Research published this week in PLoS Medicine demonstrates associations between local rainfall and temperature and cases of dengue fever, which affects an estimated fifty million people per year worldwide. But the study finds little evidence that the El Niño-Southern Oscillation – the climate cycle that occurs every three to four years as a result of the warming of the oceans in the eastern Pacific – has a significant impact on the incidence of dengue in Mexico, Puerto Rico or Thailand.
Large outbreaks of dengue, a vector-borne viral disease spread by the Aedes aegypti mosquito, occur every few years in many tropical countries. Michael Johansson, of the Centers for Disease Control and Prevention in Puerto Rico, used a technique called "wavelet analysis" to probe relationships between the local climate, El Niño, and incidence of dengue in Mexico, Puerto Rico and Thailand — three countries where dengue is endemic. They were able to separate and compare seasonal and multiyear components of each. In all three countries temperature, rainfall, and dengue incidence varied strongly on an annual scale, showing association in the wavelet analysis. On the multiyear scale however, the researchers found no association between El Niño and dengue incidence in Mexico, a statistically insignificant association in Thailand, and an association in Puerto Rico only significant for part of the study period. The authors warn that the Puerto Rico outcomes should be viewed with caution.
The authors acknowledge that El Niño could still play a role undetected by this research. But as Pejman Rohani of the University of Michigan – uninvolved in the research – states in a related Perspective, the absence of a predictable link between El Niño and dengue transmission "is an important piece of information for the development of early warning systems".
Funding: This study was supported by the US Centers for Disease Control and Prevention. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
Citation: Johansson MA, Cummings DAT, Glass GE (2009) Multiyear Climate Variability and Dengue— El Niño Southern Oscillation, Weather, and Dengue Incidence in Puerto Rico, Mexico, and Thailand: A Longitudinal Data Analysis. PLoS Med 6(11): e1000168. doi:10.1371/journal.pmed.1000168
IN YOUR COVERAGE PLEASE USE THIS URL TO PROVIDE ACCESS TO THE FREELY AVAILABLE PAPER: http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.1000168
PRESS ONLY PREVIEW OF THE ARTICLE: http://www.plos.org/press/plme-06-11-Johansson.pdf
CONTACT:
Michael Johansson
Centers for Disease Control and Prevention
Division of Vector-Borne Infectious Diseases
1324 Calle Canada
Urb Puerto Nuevo
San Juan, PR 00920
United States of America
+1 787-706-2399
mjohansson@cdc.gov
Related PLoS Medicine Perspective:
Funding:No specific funding was received for this piece.
Citation:Rohani P (2009) The Link between Dengue Incidence and El Niño Southern Oscillation. PLoS Med 6(11): e1000185. doi:10.1371/journal.pmed.1000185
IN YOUR COVERAGE PLEASE USE THIS URL TO PROVIDE ACCESS TO THE FREELY AVAILABLE PAPER: http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.1000185
PRESS-ONLY PREVIEW OF THE ARTICLE: http://www.plos.org/press/plme-06-11-Rohani.pdf
CONTACT:
Pejman Rohani
University of Michigan
Ecology and Evolutionary Biology
Room 2014A Kraus Natural Science Building
830 N. University
Ann Arbor, Michigan 48109-1048
United States of America
(734) 615-4757
(734) 763-0544 (fax)
rohani@umich.edu
Also from the PLoS Medicine Magazine section:
Supporting the use of systematic reviews in policymaking
John Lavis (of McMaster University, Hamilton, Canada) discusses how health policymakers and their stakeholders need research evidence, and the best ways evidence can be synthesized and packaged to optimize its use.
Funding: John Lavis receives salary support as the Canada Research Chair in Knowledge Transfer and Exchange. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The author declares that he has no financial competing interests, however, he does have competing professional interests in that the article highlights a number of review-derived products, some of which are commissioned or produced by World Health Organization (WHO) sponsored initiatives, Cochrane Collaboration centres and review groups, and other initiatives with which he has an affiliation. Specifically, he: (1) is a co-editor of the (WHO) Health Evidence Network/European Observatory on Health Systems and Policies policy brief series, is chair of the Pan American Health Organization (WHO's American Regional Office) Advisory Committee on Health Research, is a member of the WHO Advisory Committee on Health Research, and is a member of the Global Steering Group and the Global Resource Group for the WHO-sponsored EVIPNet initiative; (2) is a member of the Cochrane Collaboration's Effective Practice and Organization of Care (EPOC) review group and is affiliated with the Canadian Cochrane Network and Centre; and (3) is an affiliate of the European Commission-funded SUPPORT project, collaborates with the researchers leading Health-evidence.ca and Rx for Change, and leads the development and updating process for the PPD/CCNC database.
Citation: Lavis JN (2009) How Can We Support the Use of Systematic Reviews in Policymaking? PLoS Med 6(11):e1000141. doi:10.1371/journal.pmed.1000141
IN YOUR COVERAGE PLEASE USE THIS URL TO PROVIDE ACCESS TO THE FREELY AVAILABLE PAPER: http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.1000141
PRESS-ONLY PREVIEW OF THE ARTICLE: http://www.plos.org/press/plme-06-11-Lavis.pdf
CONTACT:
John Lavis
McMaster University
Clinical Epidemiology and Biostatistics
1200 Main St. West
HSC-2D3
Hamilton, ON L8N 3Z5
Canada
+1 905 525 9140 x22907
+1 905 529 5742 (fax)
lavisj@mcmaster.ca
The unintended consequences of clinical trials regulations
Alex McMahon (of the University of Glasgow, United Kingdom) and colleagues critique the International Conference on Harmonisation (ICH) guidance on good clinical practice (GCP), arguing that it is having a disastrous effect on non-commercial randomized clinical trials in Europe.
Funding: No specific funding was received for this piece.
Competing Interests: The authors have declared that no competing interests exist.
Citation: McMahon AD, Conway DI, MacDonald TM, McInnes GT (2009) The Unintended Consequences of Clinical Trials Regulations. PLoS Med 3(11): e1000131. doi:10.1371/journal.pmed.1000131
IN YOUR COVERAGE PLEASE USE THIS URL TO PROVIDE ACCESS TO THE FREELY AVAILABLE PAPER: http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.1000131
PRESS-ONLY PREVIEW OF THE ARTICLE: http://www.plos.org/press/plme-06-11-McMahon.pdf
CONTACT:
Alex McMahon
University of Glasgow Dental School
Community Oral Health
Level 8
378 Sauchiehall Street
Glasgow, City of Glasgow G2 3JZ
United Kingdom
01412119750
a.mcmahon@dental.gla.ac.uk
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