Meteorological Factors Influencing the Intensity of Malaria Outbreak in Zimbabwe

Correlation between meteorological data observed at Gokwe and intensity of malaria outbreak or the number of clinical malaria cases occurring at malaria season in whole Zimbabwe was studied. Meteorological year (Met Year) in this country starts in July at the coldest month and ends in the next June, and malaria peak season lasts from January to May. The correlation of the number of clinical malaria cases at peak season in thousand (Mp) and meteorological factors was calculated from the data in 8 years from Met Year 1990/1991 to 1997/1998. Among single factors, correlation was highest with a total rainfall (mm) in a year (Rt) followed by that in January (R1), in February (R2) and average temperature in August (Av8), showing the coefficients of 0.873, 0.870, 0.862 and 0.739, respectively. The adjusted R of the above factors were 0.722, 0.717, 0.700 and 0.470, respectively, where Av8 was non significant statistically. In two meteorological factors, the correlations higher than a single factor were a combination of R1+R2 with an adjusted R of 0.792. Malaria at peak season will be increased by more rainfall in January, February and total in a year, and may be high average temperature in August. Formulae of regression lines are as follow, and by these, intensity of malaria outbreak at malaria season will be indicated. 1. Mp = 361.30×Av8 6,182.96 (approximation) 2. Mp = 3.12×R1+43.37 (good fit) 3. Mp = 1.82×R1+2.47×R2 15.02 (best fit) 4. Mp = 1.463×Rt 323.21 (good fit for retrograde study)