On-site experience of a project to increase access to diagnosis and treatment of Chagas disease in high-risk endemic areas of Colombia

[Evaluation of a change in the serological diagnostic algorithm for Chagas disease in ColombiaAvaliação da mudança do algoritmo de diagnóstico sorológico da doença de Chagas na Colômbia]

Objective

To evaluate the effects of changing the algorithm for serological diagnosis of T. cruzi infection in departmental-level public health laboratories and in the National Reference Laboratory of Colombia, from the perspective of access to diagnosis.

Methods

A descriptive, cross-sectional study was carried out, based on secondary sources between 2015 and 2021, consolidating the number of serological tests carried out by the laboratories. A survey was developed to identify benefits and limitations in the implementation of the new algorithm for serological diagnosis. Totals, proportions, and averages of the number of tests were estimated by comparing two different periods.

Results

Information from 33 public health laboratories was analyzed, 87.9% of which processed serological assays during the period under study. The use of serological tests increased after the publication of the new guideline in 2017, and the capacity to perform the second test increased from four to 33 public health laboratories. In absolute terms, ELISAs for antigens and recombinant antigens became the most performed tests in Colombia after 2017.

Conclusions

The change in the algorithm for serological diagnosis of Chagas disease in Colombia in 2017 had positive effects on access to diagnosis since it facilitated the use of the second test. This change resulted in increased diagnostic coverage. The country's laboratories have access to a simple, timely, quality algorithm that could be implemented in almost any clinical laboratory in the country.

Laboratory evaluation of eleven rapid diagnostic tests for serological diagnosis of Chagas disease in Colombia

BACKGROUND

Chagas disease is a public health challenge in Colombia, where only an estimated 1.2% of people at risk have accessed diagnosis, while less than 0.5% of affected people have obtained treatment. The development of simplified diagnostic algorithms would enable progress in access to diagnosis; however, the current diagnostic algorithm relies on at least two laboratory-based tests that require qualified personnel, processing equipment, and infrastructure, which are still generally lacking at the primary care level. Rapid diagnostic tests (RDTs) for Chagas disease could simplify diagnosis, but their performance in the epidemiological context of Colombia is not well known.

METHODOLOGY

A retrospective analytical observational study of RDTs was performed to estimate the operational characteristics of 11 commercially available RDTs designed for in vitro detection of anti-T. cruzi IgG antibodies. The study was performed under controlled laboratory conditions using human serum samples.

PRINCIPAL FINDINGS

Eleven RDTs were assessed, ten using 585 serum samples and one using 551 serum samples. Employing the current national diagnostic algorithm as a reference standard for serological diagnosis of chronic infection, the sensitivity of the assessed RDTs ranged from 75.5% to 99.0% (95% CI 70.5-100), while specificity ranged from 70.9% to 100% (95% CI 65.3-100). Most tests (7/11, 63.6%) had sensitivity above 90%, and almost all (10/11, 90.9%) had specificity above 90%. Five RDTs had both sensitivity and specificity above 90%.

CONCLUSIONS/SIGNIFICANCE

The evaluation of these 11 commercially available RDTs under controlled laboratory conditions is a first step in the assessment of the diagnostic performance of RDTs in Colombia. As a next step, field studies will be conducted on available RDTs with sensitivity and specificity greater than 90% in this study, to evaluate performance in real world conditions, with the final goal to allow simplified diagnostic algorithms.

Analysis of the Costs Incurred by Patients with Chagas Disease: The Experience in Endemic Municipalities in Colombia

BACKGROUND

Out-of-pocket expenditure (OOP) are key costs (medical and non-medical) that many individuals incur to receive health services. They have been identified as a key access barrier for vulnerable populations, in particular for populations affected by neglected diseases with a chronic progression, such as Chagas disease. It is important to understand the costs of accessing healthcare services that are borne by patients with T. cruzi infection.

METHODOLOGY

We prepared a structured survey for patients with T. cruzi infection/Chagas disease who were all treated by the healthcare system in endemic municipalities in Colombia. The results were analyzed according to three categories: 1. The socioeconomic profiling of the patients; 2. The costs of accommodation, food and transportation, in addition to the time spent commuting; and 3. the opportunity costs (money that was not earned due to absence from work) related to treatment at the local primary care hospital or at the high-complexity reference hospital.

MAIN FINDINGS

Ninety-one patients answered the survey voluntarily. The data revealed that, when treated at the specialized reference hospital, patients spent 5.5 times more on food and accommodation, transportation costs were five times higher, and the loss of earnings was three times higher than when they were treated at the local primary care hospital. Moreover, the amount of time spent on transportation was 4 times higher at the reference hospital.

CONCLUSIONS

Providing comprehensive healthcare services for Chagas management at local primary healthcare hospitals would allow the most vulnerable patients to save on expenses related to medical and non-medical costs, in turn leading to higher adhesion to treatment thus benefiting the health system as a whole. These findings are in alignment with the WHO's World Health Assembly 2010 Resolution on the importance of treating Chagas at local primary care hospitals, thereby saving patients time and money, allowing for timely care, and promoting access to healthcare.

Are patents important indicators of innovation for Chagas disease treatment?

INTRODUCTION

Chagas disease is a neglected, endemic disease in 21 countries, spreading to non-endemic countries too. Like other neglected diseases affecting primarily low- and middle-income countries, low investment and the absence of new chemical entities from the industry occurred. Increased knowledge about the parasite, drug targets, and vector control has been observed, but this was not translated into new drugs. The partnerships of pharmaceutical companies with academies and consolidated networks to increment the new drugs and treatment research in Chagas disease are shown. The current review analyzes in detail the patents dealing with compounds candidates for new drugs and treatment. The patent search was performed using Orbit Intelligence® software in the 2001-2021 period.

AREAS COVERED

The author focused specifically on patents for the treatment, the new candidates disclosed in the patents, and the barriers to innovation.

EXPERT OPINION

Patents in Chagas disease have been increasing in the last years, although they do not bring new compounds to an effective treatment.

Comparing in vivo bioluminescence imaging and the Multi-Cruzi immunoassay platform to develop improved Chagas disease diagnostic procedures and biomarkers for monitoring parasitological cure

BACKGROUND

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and is a serious public health problem throughout Latin America. With 6 million people infected, there is a major international effort to develop new drugs. In the chronic phase of the disease, the parasite burden is extremely low, infections are highly focal at a tissue/organ level, and bloodstream parasites are only intermittently detectable. As a result, clinical trials are constrained by difficulties associated with determining parasitological cure. Even highly sensitive PCR methodologies can be unreliable, with a tendency to produce "false-cure" readouts. Improved diagnostic techniques and biomarkers for cure are therefore an important medical need.

METHODOLOGY/PRINCIPAL FINDINGS

Using an experimental mouse model, we have combined a multiplex assay system and highly sensitive bioluminescence imaging to evaluate serological procedures for diagnosis of T. cruzi infections and confirmation of parasitological cure. We identified a set of three antigens that in the context of the multiplex serology system, provide a rapid, reactive and highly accurate read-out of both acute and chronic T. cruzi infection. In addition, we describe specific antibody responses where down-regulation can be correlated with benznidazole-mediated parasite reduction and others where upregulation is associated with persistent infection. One specific antibody (IBAG39) highly correlated with the bioluminescence flux and represents a promising therapy monitoring biomarker in mice.

CONCLUSIONS/SIGNIFICANCE

Robust, high-throughput methodologies for monitoring the efficacy of anti-T. cruzi drug treatment are urgently required. Using our experimental systems, we have identified markers of infection or parasite reduction that merit assessing in a clinical setting for the longitudinal monitoring of drug-treated patients.