Go to the mothers. That’s what health workers must do to control and eliminate Chagas disease from the 21 Latin American countries where it is a persistent, often silent, scourge.
This advice was repeated so often that it took on the sound of a mantra when experts gathered to plot strategy during the 2016 Coalition for Operational Research on Neglected Tropical Diseases (COR-NTD) conference in Atlanta.
Physicians, epidemiologists, and economists who work intimately with Chagas disease in Latin America, Europe, and the United States agree that targeting infected mothers is the key to preventing the disease.
“It’s proven that treating mothers will stop the transmission to the child,” said Juan José de los Santos, head of programs for Mundo Sano in Spain. De los Santos is one of many health workers who says it’s time to rethink traditional prevention approaches.
Until recently, interventions in endemic countries have mainly focused on removing the triatomine (or “kissing”) bug, which hides in the pocked, mud brick walls of huts common in the poor Latin American communities and infects their inhabitants with T. cruzi, the Chagas-causing parasite.
A secondary prevention strategy involves testing donor blood for infection, which has reduced transfusion-related cases in all countries where Chagas is endemic.
These efforts – along with vector control – have reduced the incidence of Chagas in Latin America from 700,000 cases in the 1980s to 30,000 cases in 2016.
The next step, say researchers, is to stop the transmission of infection from mother to baby. With those measures in place, communites would next identify young children who can be helped.
Unlike adults with Chagas, infected children can be cured. Treating them can stop Chagas from transmitting across generations undetected. The difficult part is finding infected mothers and their young children.
One of the reasons Chagas is notoriously difficult to diagnose and treat is that the disease can be asymptomatic for decades. And people who feel fine, says Marcelo Paganini, don’t seek medical care.
Paganini, executive director of Mundo Sano in Argentina, estimates that only one percent of infected people in Latin America is currently treated.
Many go undetected because they have relocated from endemic to non-endemic areas where Chagas awareness is low, said Marcelo Abril, program director for Mundo Sano. His organization collaborates with the Bill & Melinda Gates Foundation and other foundations to battle neglected tropical diseases on three continents.
"I think this is the current challenge with the problem of Chagas,” said Abril, and health officials need to be aware of populations migrating from endemic areas.
As immigration from Latin America to Europe and the U.S. continues to grow, he says, cases in non-endemic areas will grow.
De los Santos says that cases of Chagas are on the uptick within a large population of Bolivian immigrants now living in Spain.
Mundo Sano implemented a program that screened, treated and educated immigrant mothers about Chagas disease. As a result, the proportion of treated patients rose from one percent to 10 percent in two years.
Eileen Stillwaggon, professor of economics at Gettysburg College, emphasized the importance of identifying and treating asymptomatic Chagas among Hispanic immigrant communities in the U.S.
The U.S. Centers for Disease Control and Prevention estimates that around 20,000 U.S. patients have already progressed to Chagas-related cardiac disease. And although numbers are hard to come by, CDC estimates that somewhere between 63 and 315 infected babies are born each year in the U.S.
Though the true cost of treating Chagas is unknown, Stillwaggon estimates that the U.S. could save $3.3 billion per birth-year cohort by screening mothers in at-risk Hispanic populations and treating infected infants to prevent symptomatic Chagas Disease.
This estimate uses an economic probability model that Stillwaggon says other countries can adapt and apply.
Lack of political will is a major reason that Chagas prevention is not a public health priority. During the COR-NTD session, several researchers expressed hope that this economic forecasting model will give ammunition to public health advocates. More research is needed, they said, for evidence-based argument.
Stillwaggon says that prevention is often maligned as too expensive to undertake.
“The cost of prevention is a rounding error in macro-economics,” she said, and her study suggests that screening mothers could save a great deal of money.
More importantly, screening and treating mothers and their babies is the most direct path to controlling and eliminating Chagas, and health programs moving forward will need to work to overcome cultural and political barriers that make it difficult to reach at-risk communities.
“Without reaching the babies, we may never be eliminating the disease,” said Stillwaggon.
A video interview is available here: https://youtu.be/i_rvcVCg_-U