Spraying Against Chagas Disease in Brazil
Introduction
Denton-Schneider and Montero (2025) analyze Brazil’s 1984-89 campaign to eliminate the transmission of Chagas disease through indoor residual spraying (IRS) against the main vector, Triatoma infestans. Chagas disease is a neglected tropical disease (NTD) that afflicts approximately 8 million people in Latin America, predominantly poor, non-white, rural populations. The disease is caused by the parasite Trypanosoma cruzi, transmitted by triatomine bugs that infest housing made of substandard materials.
The study uses multiple data sources: municipal GDP data from Ipeadata, individual-level data from Brazilian census samples, hospitalization and health spending data from Brazil’s universal health system (SUS), and mortality data from the SUS’s Mortality Information System (SIM). The paper employs a difference-in-differences strategy comparing municipalities where the vector was never present with those where it was present before IRS began, excluding the state of São Paulo which conducted its own earlier campaign in the 1960s.
Pays for Itself
Net Cost
The net cost of Brazil’s Chagas disease vector control campaign includes the expenditures on the indoor residual spraying (IRS) program from 1975-1994, offset by the savings to the public health system from reduced hospitalizations for circulatory disease.
Based on Piola (1981), Brazil’s Public Health Campaigns Superintendency (SUCAM) spent an average of $38 million per year from 1975-1980 on the surveys that mapped the presence of Triatoma infestans vectors across Brazilian municipalities. The paper assumes this same annual amount was spent for 1981-1983. Dias (1987) reported that SUCAM spent $74 million in 1986 on indoor residual spraying, and the paper assigns this $74 million figure to 1984 and 1985 as well. IRS was suspended during 1987-1989, so the paper conservatively assumes zero spending on Chagas disease control during this period. SUCAM (1994) reported an appropriation of $72 million for Chagas disease control in 1990, and the paper assumes spending decreased by 10% annually from 1991-1994 as the vector was progressively eliminated from more territory. Summing across all years from 1975-1994 yields total program expenditures of approximately $1.01 billion in 2019 USD.
The paper also calculates savings to Brazil’s universal health care system (SUS) from reduced hospitalizations and hospital care spending for circulatory system diseases. According to SUS data, circulatory system diseases accounted for approximately 0.1% of Brazilian GDP in annual hospital care spending during 2010-2019 (approximately $375 million USD per year). Using triple-differences estimates, the paper finds that hospital care spending on circulatory diseases fell by approximately 6% in 1995-1999, 16% in 2000-2004, and 18% in 2005-2010 in treated states compared to control states. The paper applies these estimated percentage reductions to the annual spending amounts for each period, discounting at 5% per year and summing from 1995-2010 to yield total present-value health care savings of approximately $1.02 billion in 2019 USD.
The net cost to the government is then calculated as $1.01 billion – $1.02 billion = -$10 million.
Willingness to Pay
The paper assumes a positive willingness to pay, based on the increased income of adults who were exposed as children to IRS during the study period. The paper finds that 1.4% of non-white adults from treatment municipalities went from earning no income to earning the median income in the 2010 census sample, which was $239 per month in 2019 USD. The paper assumes this amount was constant between 1984-2010, the size of each non-white cohort from treatment municipalities was 750,000, and that individuals entered the labor force at age 16.
This positive willingness to pay assumption excludes individuals’ valuation of their own improved health.
MVPF Summary
With a negative net cost and an assumed positive willingness to pay, the paper estimates an infinite MVPF.
References
Denton-Schneider, Jon and Eduardo Montero (2025). “Disease, Disparities, and Development: Evidence from Chagas Disease Control in Brazil.” Working Paper. https://jondentonschneider.com/files/denton-schneider_montero_chagas.pdf
Dias, João C. P. (1987). “Control of Chagas Disease in Brazil.” Parasitology Today, 3(11): 336–341. DOI: https://doi.org/10.1590/S0037-86821986000300001
Piola, Sérgio F. (1981). “Controle das grandes endemias.” Brasília:IPEA. https://repositorio.ipea.gov.br/entities/book/16d9ec26-5fcc-46f6-a6ad-03a4397e72b7
SUCAM (1994). “A Sucam e as endemias 1990/1994.” Brasília:Ministério de Saúde. https://bvsms.saude.gov.br/bvs/publicacoes/sucam_endemias_1990_1994.pdf
Policy Features
- Category
- In Kind Transfers
- Sub-Category
- Child Health, Health Adult
- Beneficiary Type(s)
- Adults, Children and Youth, Children under five, Mothers and pregnant women, Parents
- Country of Implementation
- Brazil
- Year of Implementation
- 1984
- Empirical Method
- Difference in Differences
- Research Type
- Primary
- Peer Reviewed
- No
- MVPF Publication Link
- jondentonschneider.com/files/denton-schneider_montero_chagas.pdf