title: Cholera in Cameroon, 2000-2012: Spatial and Temporal Analysis at the Operational (Health District) and Sub Climate Levels.
abstract: BACKGROUND
  Recurrent cholera outbreaks have been reported in Cameroon since 1971. However, case fatality ratios remain high, and we do not have an optimal understanding of the epidemiology of the disease, due in part to the diversity of Cameroon's climate subzones and a lack of comprehensive data at the health district level.
  
  
  RESULTS
  A unique health district level dataset of reported cholera case numbers and related deaths from 2000-2012, obtained from the Ministry of Public Health of Cameroon and World Health Organization (WHO) country office, served as the basis for the analysis. During this time period, 43,474 cholera cases were reported: 1748 were fatal (mean annual case fatality ratio of 7.9%), with an attack rate of 17.9 reported cases per 100,000 inhabitants per year. Outbreaks occurred in three waves during the 13-year time period, with the highest case fatality ratios at the beginning of each wave. Seasonal patterns of illness differed strikingly between climate subzones (Sudano-Sahelian, Tropical Humid, Guinea Equatorial, and Equatorial Monsoon). In the northern Sudano-Sahelian subzone, highest number of cases tended to occur during the rainy season (July-September). The southern Equatorial Monsoon subzone reported cases year-round, with the lowest numbers during peak rainfall (July-September). A spatial clustering analysis identified multiple clusters of high incidence health districts during 2010 and 2011, which were the 2 years with the highest annual attack rates. A spatiotemporal autoregressive Poisson regression model fit to the 2010-2011 data identified significant associations between the risk of transmission and several factors, including the presence of major waterbody or highway, as well as the average daily maximum temperature and the precipitation levels over the preceding two weeks. The direction and/or magnitude of these associations differed between climate subzones, which, in turn, differed from national estimates that ignored subzones differences in climate variables.
  
  
  CONCLUSIONS
  The epidemiology of cholera in Cameroon differs substantially between climate subzones. Development of an optimal comprehensive country-wide control strategy for cholera requires an understanding of the impact of the natural and built environment on transmission patterns at the local level, particularly in the setting of ongoing climate change.
authors.affiliation: Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America.|Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Moise C
authors.identifier: http://orcid.org/0000-0002-1359-6267
authors.initials: MC
authors.lastname: Ngwa
authors.affiliation: Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America.|Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Song
authors.initials: S
authors.lastname: Liang
authors.affiliation: Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America.|Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, College of Liberal Arts and Sciences, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Ian T
authors.initials: IT
authors.lastname: Kracalik
authors.affiliation: Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America.|Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, College of Liberal Arts and Sciences, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Lillian
authors.initials: L
authors.lastname: Morris
authors.affiliation: Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America.|Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, College of Liberal Arts and Sciences, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Jason K
authors.initials: JK
authors.lastname: Blackburn
authors.affiliation: World Health Organization country office for The Republic of Cameroon, Yaoundé, Republic of Cameroon.
authors.forename: Leonard M
authors.initials: LM
authors.lastname: Mbam
authors.affiliation: Cellule de Supervision, Suivi et Evaluation, Délégation Régionale de la Santé Publique du Centre, Yaoundé, Cameroun.
authors.forename: Simon Franky Baonga
authors.initials: SF
authors.lastname: Ba Pouth
authors.affiliation: Field Epidemiology and Laboratory Training Program, University of Yaoundé, Yaoundé, Republic of Cameroon.
authors.forename: Andrew
authors.initials: A
authors.lastname: Teboh
authors.affiliation: Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America.|Department of Biostatistics, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Higher Institute of the Sahel, University of Maroua, Maroua, Republic of Cameroon.
authors.forename: Mouhaman
authors.initials: M
authors.lastname: Arabi
authors.affiliation: Center for Inference and Dynamics of Infectious Diseases and Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle Washington, United States of America.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Sugimoto
authors.affiliation: Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America.|Department of Medicine, College of Medicine, University of Florida, Gainesville, Florida, United States of America.
authors.forename: John Glenn
authors.initials: JG
authors.lastname: Morris
mesh_terms: D000328:Adult; D002163:Cameroon / Q000453:epidemiology; D002771:Cholera / Q000453:epidemiology* / Q000401:mortality; D002980:Climate; D057231:Climate Change; D016000:Cluster Analysis; D004196:Disease Outbreaks; D006801:Humans; D015994:Incidence; D015233:Models, Statistical; D016012:Poisson Distribution; D011159:Population Surveillance; D011891:Rain; D012307:Risk Factors; D012621:Seasons; D062211:Spatio-Temporal Analysis; D013696:Temperature; D013997:Time Factors