Tuberculosis in Madagascar

A study in the Antanimora prison in Antananarivo, the capital of Madagascar, found a high prevalence of tuberculosis (TB) among detainees, with confirmed active TB cases at 0.5% (4/748) and probable cases at 1.3% (10/748), resulting in a total active TB prevalence of 1.9%. Latent TB was significantly higher at 69.6% (517/743; 95% CI: 66.27–72.89). HIV prevalence was low at 0.4% (3/745), and no TB/HIV coinfection was detected. Univariable analysis identified key risk factors, including age ≥40 years (OR = 5.6), previous incarceration (OR = 7.1), prior TB history (OR = 8.4), and TB treatment history (OR = 9.7). Multivariable regression confirmed that older detainees were 4.4 times more likely to have active TB, while those with prior TB treatment had a 6.3-fold increased risk. Although confidence intervals were wide, the associations remained significant.[1]

These findings highlight the urgent need for targeted TB screening and prevention strategies in prison settings, particularly for older detainees and those with prior TB treatment. The study successfully addressed the prevalence of TB and HIV and identified key risk factors, aligning with its research objectives. With a high latent TB burden and a notable risk concentration among older detainees, the results underscore the importance of enhanced TB surveillance and intervention efforts.[1]

Social network analysis (SNA), enriched by ethnographic data on human interactions, can enhance the realism of compartmental models by capturing the impact of social structures on disease transmission. From another study in Madagascar, despite 15 years of intervention, latent TB infection prevalence showed only a slight decline, highlighting the persistence of TB reservoirs even after systematic treatment of active cases. The intensity of social contacts plays a crucial role in TB exposure, yet conventional transmission models often overlook these inter-community differences, underscoring the need for more nuanced approaches to understanding and controlling TB spread.[2]

References:

1. Rakotomanana, F., Dreyfus, A., Randrianarisoa, M.M., Raberahona, M., Chevallier, E., Andriamasy, H.E., Bernardson, B.A., Ranaivomanana, P., Ralaitsilanihasy, F., Rasoamaharo, M. and Randrianirisoa, S.A., 2024. Prevalence of pulmonary tuberculosis and HIV infections and risk factors associated to tuberculosis in detained persons in Antananarivo, Madagascar. Scientific Reports, 14(1), p.8640.

2. Pando, C., Hazel, A., Tsang, L.Y., Razafindrina, K., Andriamiadanarivo, A., Rabetombosoa, R.M., Ambinintsoa, I., Sadananda, G., Small, P.M., Knoblauch, A.M. and Rakotosamimanana, N., 2023. A social network analysis model approach to understand tuberculosis transmission in remote rural Madagascar. BMC Public Health, 23(1), p.1511.