A ten-year cross sectional study of trends of laboratory-confirmed Malaria in the republic of South Africa
Date
2012
Authors
Mwagomba, Beatrice Lydia
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Abstract
Introduction:
Malaria is a vector-borne parasitic disease with heterogeneous distribution in time and space.
The sub-Saharan African region harbours the largest proportion of the global malaria cases and
contributes over 90% to the deaths due to malaria. The present study aimed to identify trends of
laboratory-confirmed malaria in both malaria endemic and non-endemic areas of South Africa
over a period of ten years (January 2000 to December 2009). The association between malaria
and demographic characteristics was also explored.
Materials and methods
This analytical cross-sectional study used secondary malaria surveillance data obtained from
eight South African provinces through the National Health Laboratory Service. A population
subset that utilised public health care facilities during the study period was included. Chi-square
test of proportions was used to test if there were significant differences in the distribution of
demographic and temporal characteristics among the laboratory-confirmed malaria cases. Annual
parasite incidence of malaria was calculated to estimate malaria incidence in the population.
Logistic regression models were constructed to determine the association between malaria and
demographic characteristics.
Results:
There were 175,069 suspected malaria cases from the endemic provinces of which 26,367
(15.1%) were laboratory confirmed; 130,980 (40.2%) suspected cases were from non-endemic
provinces of which 42,488 (32.4%) were diagnosed as malaria. The overall malaria positivity
rate was 21.4%. There were more cases of malaria among males (62.9%) than females, among
individuals aged 25-44 years (44.0%) than individuals in any other age-group and among those
living in non-endemic provinces (60.8%) than those living in endemic provinces.
v
A linear downward trend in malaria incidence was observed over the ten-year period (p<0.001).
Thus, malaria incidence declined from an overall API of 64 per 100,000 population in 2000 to 50
per 100,000 population in 2009. The incidence of malaria in both endemic and non-endemic
provinces was highest in the month of January (15 per 100,000 and 24 per 100,000 respectively).
The following demographic factors were found to be independently associated with increased
malaria incidence: male gender (adjusted odds ratio (aOR) 1.54, CI: 1.51-1.57, p<0.001) and
non-endemic province-type (aOR 2.68, CI: 2.63-2.73, p<0.001). Age was inversely associated
with malaria incidence. Individuals in 45-64 and ≥ 65 year age-groups were 20% (aOR 0.80, CI:
0.77-0.82, p<0.001) and 51% (aOR 0.49, CI: 0.46-0.53, p<0.001) less likely to have malaria
respectively.
Conclusion:
There was a high incidence of laboratory-confirmed malaria in previously malaria non-endemic
parts of South Africa especially Gauteng and North West provinces in the past decade. Targeted
information, education and communication (IEC) to all travelers during the annual festive and
holiday seasons should be reinforced to minimize importation of malaria into non-endemic areas.
Description
A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand,
Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in
Epidemiology in the field of Epidemiology and Biostatistics
Johannesburg, April 2012