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Notification 18/10/2022

Chagas’ Disease Control and Notification Policies: facing the epidemiological silence with the notification of chronic cases

Vitória P. Ramos, Juan Carlos Cubides e Matheus Oliveira1

1 MSF – Doctors Without Borders


Brazil has made great advances in recent decades in terms of vector control of Chagas’ disease (CD), substantially reducing the transmission and occurrence of acute cases. Thanks to efforts undertaken at the national level to control the vector, especially since the late 1970s, in 2006 Brazil received the International Certification for the Elimination of Transmission of Chagas’ Disease by its main vector [1]. As important as it is to reach this level, which deserves to be valued and recognized, this great achievement had the undesired consequence of making people affected by Chagas’ Disease invisible, especially those who are already living with the chronic phase of the disease. These people still suffer from the lack of adequate public policies to face this situation, which is still a major public health problem, but politically neglected.

Within this scenario, the epidemiological surveillance of chronic cases of Chagas still represents an important medical and social challenge in the affected countries. Commonly, one only works with estimates and the real extent of the problem and its consequences is little known, which makes it difficult to plan adequate responses by health systems [2].

According to the II Brazilian Consensus on Chagas’ Disease [3], the most recent estimates of the number of people affected by CD in Brazil range from 1.9 million to 4.6 million people. This expressive variation between different studies is just proof of the epidemiological silence that we currently face in relation to this disease. Even more serious are the estimates that more than 80% of these people have never had access to the diagnosis [3], that is, they are unaware of their condition and have been denied their right to antiparasitic treatment and will possibly only enter the health system when they suffer problems as a result. disease manifestation that could have been avoided with timely diagnosis and treatment.

The economic impact of the disease during the chronic stage is high as it affects individuals in the full productive phase, from 30 years of age onwards [4]. If we consider that between 30 and 40% of infected people will develop severe cardiac and digestive injuries within a period of 5 to 20 years after infection and will require the use of complex supportive therapies, the estimated costs amount to approximately US$ 750 million per year. Furthermore, life expectancy for these chronic cases is reduced by between 5 and 10 years once they reach the clinical diagnosis [5].One of the main and first ways within the scope of public policies to begin to face this great challenge is to find people who are at this stage of the disease and to have concrete knowledge of the epidemiological reality in the country. Today in Brazil, only acute cases of CD are notifiable, which is done by filling in the Investigation Form for Acute Chagas’ disease, standardized throughout the national territory. Between 2000 and 2013, there were a total of 1570 cases of Acute Chagas’ disease (ACD) registered, with almost 70% of cases originating from the form of oral transmission, which increased significantly after the outbreak of oral transmission by sugarcane in Santa Catarina in 2005.

Source: Boletim Epidemiológico. Vol. 46 – nº 21 – 2015 – Doença de Chagas aguda no Brasil: série histórica de 2000 a 2013.

The epidemiological bulletins provided by the Ministry of Health indicate that chronic cases predominate in the country, but the last survey carried out to investigate chronic cases took place in 2008 and did not have a broad diagnostic screening that would make it possible to really know the number of chronic cases in the country.

Reporting chronic cases is an action of great importance in public health, as morbidity and mortality data are usually inaccurate. The number of carriers of chronic chagasic heart disease, for example, is estimated on an unrealistic basis (number of infected), based on an assumed (extremely variable) percentage of cases that are expected to develop this type of clinical manifestation, without considering regionally marked differences. The infected population is unknown, mainly because the spontaneous demand for medical services corresponds almost exclusively to severe chronic cases. The notification would then make it possible to know the distribution, magnitude and tendency of the disease and the identification of risk factors, social, economic and environmental conditions, with the objective of subsidizing the planning, execution and evaluation of prevention and control activities [6].

There is already a state experience in Brazil of compulsory notification of chronic cases: in 2013, in the state of Goiânia, Resolution No. 004/2013 – GAB/SES-GO established the obligation to notify chronic cases of CD, among other conditions to be included in addition to the national list of compulsory notification. According to the current coordinator of the state’s Chagas’ disease program, Dr. Liliane Siriano, during this period a field visit was carried out in the interior of the state, which found the great lack of coverage and assistance to people affected by CD in the chronic phase. The State did not reach these people, who represented almost all cases in Goiás. It was then decided that the notification of the chronic patients would be a way to find and safeguard them in a more structural way. This small change has been improving the quality of epidemiological information in the state. According to data from SES-GO, since it became compulsory notification, 1540 chronic cases of CD were registered in the state until March 2016. SES believes that the follow-up of chronic cases can reduce the high annual average of deaths from the disease (750 deaths/year) and improve the quality of life of these people. There are still challenges for the effective implementation of the practice that could be facilitated if there were mandatory at the national level [7].

In addition to reporting chronic cases, Goiás is also the pioneer state in including the diagnosis of CD in the prenatal kit. In partnership with the Association of Parents and Friends of the Exceptional People (APAE) Goiânia, the Goiás State Health Department (SES-GO) created the Program for the Protection of Pregnant Women in Goiás in 2002, better known as the “Mother’s Test”, which performs neonatal screening using the collection of peripheral blood on filter paper to prevent vertical transmission of genetic and infectious diseases. In a study that analyzed samples from 348,037 pregnant women from 245 municipalities in the state of Goiás from 2003 to 2009 [8], tests were included to screen for viral (hepatitis B, hepatitis C, HIV, rubella, HTLV and CMV), bacterial (syphilis) and protozoa (toxoplasmosis and Trypanosoma cruzi infection).

The great surprise raised in this study occurred precisely in the data on the prevalence of Chagas’ Disease, which was the third most prevalent disease among the analyzed infectious diseases, with a prevalence of 0.51% (1,768 cases). The first two diseases were syphilis, with 1.16%, and toxoplasmosis, with 0.67%. For comparative purposes, HIV came in sixth, with 0.13% prevalence. The article in question states that the CD data surprised researchers because there was a common sense that there would not be so many women of childbearing age affected by the disease, another proof that the low number of reported cases of the disease in the country is more an epidemiological silence and that an active search accompanied by efficient diagnostic screening could surprise even more and avoid further harm to these people and to the health system.

Another interesting finding from the study of samples from the Mother’s Test is that, among the detected cases of CD, 794 women attended consultations after the diagnosis for follow-up, and 56.3% of them were born in Bahia and 32.9% in Goiás, the others coming from several other states. This highlights the need to multiply this experience in other states.

Research on CD over the last decade in the country has been characterized by discussions about expanded epidemiological surveillance, supported by sero-epidemiology strategies (emphasizing the importance of identifying chronic patients and referring them to health services) and more recently, by the treatment of chronic cases in younger patients [9].Considering the characteristic of CD in being a silent disease, often without symptoms, it is even more difficult to transform so many quality academic works and, especially, the voice of the affected people into a concrete public policy agenda and face in an active way this public health problem that is almost forgotten. Improving the quality of epidemiological data on CD in Brazil is a challenge that must be faced and the country owes a great deal to Carlos Chagas and the generations of entire families affected for centuries by this, which is “the most Brazilian of diseases”. After great efforts to control transmission, finding the affected people and expanding diagnosis and treatment to them in primary health care is the step that remains to be taken. Compulsory national reporting of chronic cases is a key part of this puzzle.