By knowing the incidence of an infectious disease, we can ascertain the high
risk factors of the disease as well as the e ectiveness of awareness programmes
and treatment strategies. Since the work of Hugo Muench in 1934, many
methods of estimating the force of infection have been developed, each with
their own advantages and disadvantages.
The objective of this thesis is to explore the di erent compartmental models
of infectious diseases and establish and interpret the parameters associated
with them. Seven models formulated to estimate the force of infection were
discussed and applied to data obtained from CAPRISA. The data was agespeci
c HIV prevalence data based on antenatal clinic attendees from the
Vulindlela district in KwaZulu-Natal.
The link between the survivor function, the prevalence and the force of infection
was demonstrated and generalized linear model methodology was used
i
to estimate the force of infection. Parametric and nonparametric force of
infection models were used to t the models to data from 2009 to 2010. The
best tting model was determined and thereafter applied to data from 2002
to 2010. The occurring trends of HIV incidence and prevalence were then
evaluated. It should be noted that the sample size for the year 2002 was considerably
smaller than that of the following years. This resulted in slightly
inaccurate estimates for the year 2002.
Despite the general increase in HIV prevalence (from 54.07% in 2003 to
61.33% in 2010), the rate of new HIV infections was found to be decreasing.
The results also showed that the age at which the force of infection peaked
for each year increased from 16.5 years in 2003 to 18 years in 2010.
Farrington's two parameter model for estimating the force of HIV infection
was shown to be the most useful. The results obtained emphasised the importance
of HIV awareness campaigns being targeted at the 15 to 19 year
old age group. The results also suggest that using only prevalence as a measure
of disease can be misleading and should rather be used in conjunction
with incidence estimates to determine the success of intervention and control
strategies. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/11116 |
| Date | January 2013 |
| Creators | Balakrishna, Yusentha. |
| Contributors | Mwambi, Henry G. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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