It is known that in high TB incidence settings the rate of recurrent TB disease is much higher than the rate for first-time disease. It is not clear why the rate of reinfection disease can be elevated compared to the rate of primary disease. We set about attempting to estimate the actual values of the risk of reinfection and the rate of progress to disease for the high-incidence community of Ravensmead-Uitsig in Cape Town.
In the SACEMA Quarterly of November 2015 we published an item from Alide Dasnois about compensating miners for the burden of lung disease. On 6 March 2016 City Press published an article titled “Silicosis claims: Anglo has to cough up nearly R500m” which reports on a first step in the process of paying the individual claims.
Alide Dasnois, a South African journalist and former editor of the Cape Times, has written an an article titled “The long battle to get the mines to cough up” which is about compensating miners for the burden of lung disease. The importance of this issue has been highlighted before in a SACEMA Quarterly article by Tony Davies giving an historical overview on occupational lung disease in South Africa.
Household contacts of active TB cases are at increased risk of TB infection and several studies have measured TB prevalence in this key population. The study described here not only measured TB prevalence, but also measured TB and HIV incidence in the household contacts of 729 TB index cases in the Matlosana sub-district in North West Province. We concluded that the efficacy of contact tracing for TB control purposes might be improved by a second intensified case finding visit and by providing preventive treatment against TB for both HIV-infected and HIV-seronegative household contacts of TB cases.
Expanding ART coverage to healthier HIV patients is widely regarded as a potential strategy for addressing the rampant TB epidemic in high HIV-TB burden settings. Estimating the population-level impact of ART expansion on TB disease has proven challenging. We set out to estimate the potential effects of changing HIV treatment policy on TB outcomes in South Africa, comparing the results of three independent TB models. This project was part of a broader effort to shed light on the consequences of HIV policy changes, through model comparison and consensus building, a process pioneered in the HIV modelling field by the HIV Modelling Consortium.
Existing approaches to TB control have been no more than partially successful in areas with high HIV prevalence. In the context of increasingly constrained resources, mathematical modelling can augment understanding and support policy for implementing strategies most likely to bring public health and economic benefits. Recognising the urgency of TB control in high HIV prevalence settings and the potential contributions of modelling, the TB Modelling and Analysis Consortium (TB MAC) convened its first meeting between empirical scientists, policy makers and mathematical modellers in September 2012 in Johannesburg. Here we present a summary of results from these discussions, as well as progress made in South Africa.
In 2011, the Ministry of Health in Swaziland joined forces with the WHO, the Global Fund and SACEMA to do the first in depth health programmes progress evaluation using triangulation from key empirical data sources. The focus was on key questions like: Given increasing coverage of ART, has ART reduced adult and/or infant mortality?; Can TB trends be related to trends in HIV prevalence, ART coverage and combined TB/HIV interventions?; Can trends in infant mortality be related to uptake of PMTCT?
A considerable share of South Africa’s tuberculosis burden affects those people who have previously been treated for tuberculosis – many of them successfully. In a retrospective cohort study that was conducted using tuberculosis treatment register data from two communities in suburban Cape Town, it was found that the hazard rate of re-treatment for smear-positive tuberculosis was between 3- and 5.26-times higher in tuberculosis cases who had defaulted from treatment compared to successfully treated cases. But although the rate of re-treatment was substantially higher among defaulters, cases after treatment success account for the vast majority of smear-positive re-treatment cases due to the fact that far more tuberculosis cases were successfully treated than had defaulted.
The system of oscillating labour migration, especially to the gold mines in South Africa, has helped to spread TB throughout southern Africa and it now helps to spread HIV. This article illustrates this link by reporting on a study on the impact of migrant labour in the mines in South Africa on the burden of HIV and TB in Mozambique. Furthermore, modelling studies have shown that even if we maintain the same patterns of sexual behaviour the presence or absence of migration can lead to dramatically different outcomes. Unless a comprehensive and fully coordinated multi-country and multi-sectoral programme is implemented and followed through, we may find that the HIV and TB epidemics are far more resilient than consideration of the epidemics in each country suggests.
The Mycobacterium tuberculosis (TB) bacilli’s potency to cause persistent latent infection that is unresponsive to the current cocktail of TB drugs is strongly associated with its ability to adapt to changing intracellular environments, and tolerating, evading and subverting host defence mechanisms. We applied a combination of bioinformatics and mathematical modelling methods to enhance the understanding Read More