Title page for ETD etd-11092011-084849

Document Type Master's Dissertation
Author Pienaar, Nicolaas Johannes
URN etd-11092011-084849
Document Title A retrospective analysis of the epidemiology of Rift Valley fever in South Africa
Degree MSc
Department Production Animal Studies
Advisor Name Title
Prof P N Thompson Supervisor
  • South Africa
  • risk factors
  • multiple logistic regression
  • Southern Oscillation Index
  • El Niño
  • La Niña
  • Rift Valley fever
  • epidemiology
Date 2011-09-09
Availability unrestricted

The aim of this study was to investigate the epidemiology of Rift Valley fever (RVF) in South Africa. The first part of the study consisted of the compilation of a full history of RVF in South Africa. This was done by compiling all references to outbreaks of the disease in South Africa from all available literature, annual reports, disease reports and animal disease databases. The geographic location and temporal occurrence of each outbreak was recorded as accurately as allowed by the available records. The result was a better and more complete picture than has hitherto been available of the spatial and temporal distribution of RVF for the period 1950, when the disease was first recognised in South Africa, to 2010. Several smaller outbreaks not mentioned in the literature were found. It emerged that large outbreaks occur in the Free State Province, Eastern Cape Province and Northern Cape Province with long periods of absence and smaller outbreaks occur in KwaZulu-Natal, Mpumalanga and Gauteng at more frequent intervals.

The second part of the study used the data collected during the first part of the study to determine which climatic and other environmental factors could have played a role in the occurrence of RVF in South Africa. Multiple logistic regression analysis was used to estimate associations between the various potential risk factors and the occurrence of Rift Valley fever.

The study found that the El Niño/Southern Oscillation influence on rainfall in South Africa has an effect on the occurrence of RVF in South Africa which is opposite to the effect that has been described for Kenya. A positive Southern Oscillation Index (La Niña) increases the likelihood of a RVF outbreak in South Africa.

The study also found that very high rainfall during the summer months (December to February) is an important risk factor for the occurrence of RVF and it confirmed the increased risk of an outbreak where pans and wetlands are present as reported in several articles and disease reports on past outbreaks. Several other factors, such as minimum and maximum temperature were also found to have a statistically significant effect on the occurrence of Rift Valley fever.

Copyright © 2011, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria

Please cite as follows:

Pienaar, NJ, 2011, A retrospective analysis of the epidemiology of Rift Valley fever in South Africa, MSc (Production Animal Studies) dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-11092011-084849/>


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