Access to diagnosis and treatment of Chagas disease/infection in endemic and non-endemic countries in the XXI century

Abstract

In this article, Médicos Sin Fronteras (MSF)Spain

Usefulness of PCR-based assays to assess drug efficacy in Chagas disease chemotherapy: value and limitations

“…In this sense, therapeutic results have differed between countries probably due to differences in T. cruzi strains from distinct geographical areas. The general assumption, however, is that the earlier the diagnosis is made and the specific treatment initiated, the greater the chance of parasitological cure (WHO 1991, Villa et al 2007). Nevertheless, one of the greatest concerns in Chagas disease is the absence of reliable methods or a diagnostic gold standard for the evaluation of chemotherapy efficacy in treated patients.…”

“…Treatment in early life -It is well documented that infants infected during the early years of life represent those patients amenable to specific treatment with the greatest possibility of cure , Villa et al 2007). Children better tolerate a long-term treatment and present high indices of cure, as demonstrated by two randomized placebo-controlled trials with benznidazole in Brazil and in Argentina (Sosa Estani et al 1998), where negative seroconversion was estimated in around 60% of the benznidazole-treated children.…”

“…There is a need for new drugs with fewer secondary effects and higher trypanomicidal activity. The advancement in studies with posaconazole, already commercialized for systemic mycotic infections, and ravuconazole, in the animal experimental phase, is urgent (Villa et al 2007). However, one of the key issues concerning Chagas disease is still that of diagnosis.…”

“…It is likely that the autoimmune component of Chagas disease is a parasite-induced disorder; therefore, etiologic treatment should focus on clearance of parasites and not on suppressing a presumed pathogenic anti-self response. The few studies that attempted to demonstrate the effectiveness of etiologic treatment were only performed during the last decade of the 20th century, probably based on molecular biology evidence that, at that time, proved that the parasite remained in targeted tissues meaning that they could no longer attribute the etiopathogeny exclusively to immunological mechanisms (Villa et al 2007). Observational studies found that benznidazole treatment for patients with chronic Chagas disease delayed or prevented clinical progression of heart damage, but was not believed to be able to eliminate the parasite during the chronic phase of infection (Viotti et al 1994, Fabbro De Suasnábar et al 2000, Cançado 2002).…”

“…Research and development of new diagnostic tests and drugs for the etiologic treatment of Chagas disease have been almost non-existent when compared with other non-neglected infectious diseases, such as acquired immunodeficiency syndrome (AIDS). Benznidazole and nifurtimox, the only two drugs available for treatment, have been in the market for more than 30 years and their pharmacokinetic characteristics, formulations, efficacy and secondary effects are far from ideal (Villa et al 2007). The evaluation of cure of Chagas disease is certainly the more complex aspect of its treatment, leading several times to diverse and controversial results in relation to both parasitological and clinical cures.…”