Abstract

Drug-resistant tuberculosis comprises 3% of the total caseload in South Africa. An outpatient, decentralized care strategy was introduced by the South African National Department of Health in 2011 to treat drug-resistant TB; nevertheless, this raised expenses and put the long-term sustainability of tuberculosis prevention strategies in jeopardy. In an already overburdened healthcare system, these high costs may lead to more restrictions on who can receive treatment and for how long, to the point where policies may be implemented that terminate treatment earlier than would have been the case with untreated cases returning to the public. Home confinement is now recognised as a viable intervention option when combined with safety precautions such as ventilation and medical support.  However, little is known about the about the risk of infection in this context. This study assessed the effectiveness of wind-driven roof turbines in enhancing ventilation and their potential to lower the risk of Mycobacterium tuberculosis infection in a residential setting. Eight houses were selected and divided equally into intervention (wind turbines installed) and control groups, using a pairwise comparison method. The CO₂ decay method was used as a surrogate to determine ventilation in the houses, The wind-driven roof turbines’ potential to lower the risk of Mycobacterium tuberculosis infection was stochastically evaluated using the Wells-Riley mathematical model. While other factors such as season and time of day influenced CO₂ decay, the presence of the wind-driven roof turbine was the biggest predictor of its degradation, according to the mixed effects regression model. During two seasons – winter and spring - installation of a roof turbine resulted in twofold ventilation rates compared to the control houses. Consequently, the Wells-Riley model predicted a twofold reduction in the probability of infection in the intervention compared to the control households. Low cost, low-maintenance wind-powered roof turbines are an effective way to improve ventilation in houses and should be taken into consideration as an extra line of defence against Mycobacterium TB and other diseases in residential environments. This can help guide future initiatives that facilitate ongoing care and prevent the spread of infectious diseases by facilitating the connection between home-based/community care, where patients who are still contagious but have some chance of recovering, and designated inpatient medical facilities, where patients receive initial treatment.