Abstract:
BACKGROUND : Malaria is seasonal and this may influence the number of children being treated as outpatients in
hospitals. The objective of this study was to investigate the degree of seasonality in malaria in lakeshore and highland
areas of Zomba district Malawi, and influence of climatic factors on incidence of malaria.
METHODS : Secondary data on malaria surveillance numbers and dates of treatment of children <5 years of age
(n = 374,246) were extracted from the Zomba health information system for the period 2012–2016, while data on
climatic variables from 2012 to 2015 were obtained from meteorological department. STATA version 13 was used
to analyse data using non-linear time series correlation test to suggest a predictor model of malaria epidemic over
explanatory variable (rainfall, temperature and humidity).
RESULTS : Malaria cases of children <5 years of age in Zomba district accounts for 45% of general morbidity. There was
no difference in seasonality of malaria in highland compared to lakeshore in Zomba district. This study also found
that an increase in average temperature and relative humidity was associated of malaria incidence in children <5 year
of age in Zomba district. On the other hand, the difference of maximum and minimum temperature (diurnal temperature
range), had a strong negative association (correlation coefficients of R2
= 0.563 [All Zomba] β = −1295.57
95% CI −1683.38 to −907.75 p value <0.001, R2
= 0.395 [Zomba Highlands] β = −137.74 95% CI −195.00 to −80.47
p value <0.001 and R2
= 0.470 [Zomba Lakeshores] β = −263.05 95% CI −357.47 to −168.63 p value <0.001) with
malaria incidence of children <5 year in Zomba district, Malawi.
CONCLUSION : The diminishing of malaria seasonality, regardless of strong rainfall seasonality, and marginal drop of
malaria incidence in Zomba can be explained by weather variation. Implementation of seasonal chemoprevention of
malaria in Zomba could be questionable due to reduced seasonality of malaria. The lower diurnal temperature range
contributed to high malaria incidence and this must be further investigated.
