September 2010

Short item Published on September 20, 2010

Unintended consequences: on the importance of doing things properly

I. Jean Humphrey and the ZVITAMBO Trial Over the past 40 years as a scientific researcher I have had the good fortune to work for a small number of extraordinary individuals who have produced results of some importance in the greater scheme of things. What has struck me about those results is that they have Read More

Short item Published on September 20, 2010

Modelling the potential impact of age-targeted early HIV treatment initiation in South Africa

At the 3rd Annual Congress of ISPOR South Africa, Wim Delva – senior researcher at SACEMA – gave a presentation on age-targeted early HIV treatment initiation. As reported earlier in the SACEMA Quarterly, universal, immediate antiretroviral treatment (ART) has the potential to reduce HIV incidence dramatically (1). However, this may not be feasible nor affordable Read More

Short item Published on September 20, 2010

Selecting HIV infection prevention interventions in Malawi

In the April 2010 issue of the SACEMA Quarterly an article was published describing a simple mathematical model developed by the UNAIDS Reference Group for Estimates, Modelling and Projections to help countries estimate the proportion of new infections that occur through key transmission modes (1). Indicated was that this type of in-country analysis could be Read More

Published on September 20, 2010 by

Editorial: Changing of the Guard at SACEMA

With effect from 1 July 2010 I have stepped down as Director of SACEMA. I shall continue to work as a Senior Research Fellow, focussing on my research in the area of tsetse and trypanosomiasis biology and control. The Director’s position has been filled by Dr Alex Welte, who has moved to Stellenbosch from the Computational and Applied Mathematics (CAM) at the University of the Witwatersrand. Alex is no stranger to SACEMA having been involved from the earliest days and he made a huge contribution to our early development in helping to secure major international funding. There is every reason to be extremely optimistic about an exciting future for SACEMA under Alex Welte’s leadership and I am sure you will all join me in wishing Alex well as the head of this organisation over the coming years.

Published on September 20, 2010 by

What determines the type-specific prevalence of high-risk human papillomavirus (HPV) infection? – implications for the impact of vaccination against types 16 and 18

Cervical cancer is the second most common cancer among women worldwide, with an annual incidence of approximately half a million cases. Over 80% of these occur in developing countries. It is firmly established that persistent infection with one of the so-called high-risk human papillomavirus (hrHPV) types is a prerequisite for the development of cervical cancer. Estimating the impact of HPV vaccination on the reduction in the rate of cervical cancer requires an understanding of the determinants that govern the prevalence of the various hrHPV types prior to vaccination. The fact that hrHPV is sexually transmitted partly explains the age-specific patterns in hrHPV prevalence data and the geographic variation in hrHPV infection risk. However, it is unclear why some high-risk types are more widespread than others.

Published on September 20, 2010 by

Should we be worrying about Bovine TB?

Given the enormous burden that the current HIV/AIDS and TB epidemics have imposed on rural areas in the eastern and central provinces of South Africa, how much attention should the National and Provincial governments be paying to zoonotic diseases such as bovine TB (BTB) in these areas? The answer lies not only in the extent to which BTB posses an additional burden on human health in the region, but also on the degree to which it threatens food security, exacerbates poverty, and threatens conservation and green tourism.

Published on September 20, 2010 by

Can mixed infection explain the high prevalence of TB in crowded areas with high strain diversity and low HIV prevalence?

There are many different strains of TB. If there happen to be many strains circulating in a population, then individuals could be infected with more than one strain at a time which we define as mixed infection. This article focuses on the question whether mixed infection can explain the high prevalence of TB in some areas with overcrowding, low HIV prevalence and a high diversity in TB strains. The aim was to identify the factors that characterize mixed infection and investigate their impact on both the prevalence of TB and the proportion of mixed infection in these areas. To investigate the impact of these parameters, a mathematical model was developed for TB transmission dynamics that accounts for mixed infection.