title: Clinical Malaria Transmission Trends and Its Association with Climatic Variables in Tubu Village, Botswana: A Retrospective Analysis.
abstract: Good knowledge on the interactions between climatic variables and malaria can be very useful for predicting outbreaks and preparedness interventions. We investigated clinical malaria transmission patterns and its temporal relationship with climatic variables in Tubu village, Botswana. A 5-year retrospective time series data analysis was conducted to determine the transmission patterns of clinical malaria cases at Tubu Health Post and its relationship with rainfall, flood discharge, flood extent, mean minimum, maximum and average temperatures. Data was obtained from clinical records and respective institutions for the period July 2005 to June 2010, presented graphically and analysed using the Univariate ANOVA and Pearson cross-correlation coefficient tests. Peak malaria season occurred between October and May with the highest cumulative incidence of clinical malaria cases being recorded in February. Most of the cases were individuals aged >5 years. Associations between the incidence of clinical malaria cases and several factors were strong at lag periods of 1 month; rainfall (r = 0.417), mean minimum temperature (r = 0.537), mean average temperature (r = 0.493); and at lag period of 6 months for flood extent (r = 0.467) and zero month for flood discharge (r = 0.497). The effect of mean maximum temperature was strongest at 2-month lag period (r = 0.328). Although malaria transmission patterns varied from year to year the trends were similar to those observed in sub-Saharan Africa. Age group >5 years experienced the greatest burden of clinical malaria probably due to the effects of the national malaria elimination programme. Rainfall, flood discharge and extent, mean minimum and mean average temperatures showed some correlation with the incidence of clinical malaria cases.
authors.affiliation: Okavango Research Institute, University of Botswana, Private Bag 285, Maun, Botswana.
authors.forename: Elijah
authors.initials: E
authors.lastname: Chirebvu
authors.affiliation: College of Health Sciences, Howard Campus, University of KwaZulu-Natal, Durban 4041, South Africa.
authors.forename: Moses John
authors.initials: MJ
authors.lastname: Chimbari
authors.affiliation: Okavango Research Institute, University of Botswana, Private Bag 285, Maun, Botswana.
authors.forename: Barbara Ntombi
authors.initials: BN
authors.lastname: Ngwenya
authors.affiliation: Discipline of Public Health Medicine, School of Nursing and Public Health, University of KwaZulu-Natal, Durban, South Africa.
authors.forename: Benn
authors.initials: B
authors.lastname: Sartorius
mesh_terms: D001902:Botswana / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D002980:Climate; D006801:Humans; D015994:Incidence; D007223:Infant; D008288:Malaria / Q000453:epidemiology / Q000635:transmission*; D012189:Retrospective Studies