Abstract
Chagas disease (CD) persists as one of the neglected tropical diseases (NTDs) with a particularly large impact in the Americas. The World Health Organization (WHO) recently proposed goals for CD elimination as a public health problem to be reached by 2030 by means of achieving intradomiciliary transmission interruption (IDTI), blood transfusion and transplant transmission interruption, diagnostic and treatment scaling-up and prevention and control of congenital transmission. The NTD Modelling Consortium has developed mathematical models to study Trypanosoma cruzi transmission dynamics and the potential impact of control measures. Modelling insights have shown that IDTI is feasible in areas with sustained vector control programmes and no presence of native triatomine vector populations. However, IDTI in areas with native vectors it is not feasible in a sustainable manner. Combining vector control with trypanocidal treatment can reduce the timeframes necessary to reach operational thresholds for IDTI (<2% seroprevalence in children aged <5 years), but the most informative age groups for serological monitoring are yet to be identified. Measuring progress towards the 2030 goals will require availability of vector surveillance and seroprevalence data at a fine scale, and a more active surveillance system, as well as a better understanding of the risks of vector re-colonization and disease resurgence after vector control cessation. Also, achieving scaling-up in terms of access to treatment to the expected levels (75%) will require a substantial increase in screening asymptomatic populations, which is anticipated to become very costly as CD prevalence decreases. Further modelling work includes refining and extending mathematical models (including transmission dynamics and statistical frameworks) to predict transmission at a sub-national scale, and developing quantitative tools to inform IDTI certification, post-certification and re-certification protocols. Potential perverse incentives associated with operational thresholds are discussed. These modelling insights aim to inform discussions on the goals and treatment guidelines for CD.
Highlights
With an estimated 8–10 million cases worldwide, Chagas disease (CD; known as American trypanosomiasis) remains a major cause of heart disease morbidity, mortality and economic burden, in endemic Latin American countries[1]
CD is a parasitic disease caused by the protozoan Trypanosoma cruzi, and transmitted mainly by domiciliated triatomine (Reduviidae) vectors in tropical areas of the Americas
Large areas in endemic countries are populated by sylvatic triatomine species for which traditional vector control is not effective in a sustainable manner
Summary
With an estimated 8–10 million cases worldwide, Chagas disease (CD; known as American trypanosomiasis) remains a major cause of heart disease morbidity, mortality and economic burden, in endemic Latin American countries[1]. Prevalence of infection and house infestation in many areas; role of native vector species in transmission; resistance status of vector populations to currently available insecticides; disentangling the impact of chemical vector control from that of housing improvement; efficacy of trypanocidal treatment under various rates of abandonment. Modelling studies have indicated that potentially combining highly effective vector control with trypanocidal treatment of humans residing in endemic areas would substantially reduce the time required to achieve operational serological thresholds for IDTI as well as infection incidence and prevalence[18] (Figure 2). Large areas in endemic countries are populated by sylvatic triatomine species for which traditional vector control is not effective in a sustainable manner For those areas more experimental and modelling work is needed to better understand both transmission and control strategies. Modelling priorities to support goals in the 2030 horizon and beyond Table 2 outlines the priority modelling questions for further research that were elaborated in discussion with the WHO
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
