REVIEW Experimental models in Chagas disease: a review of the methodologies applied for screening compounds against Trypanosoma cruzi Cristina Fonseca-Berzal 1 & Vicente J. Arán 2 & José A. Escario 1 & Alicia Gómez-Barrio 1 Received: 3 July 2018 /Accepted: 11 September 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract One of the main problems of Chagas disease (CD), the parasitic infection caused by Trypanosoma cruzi, is the lack of a completely satisfactory treatment, which is currently based on two old nitroheterocyclic drugs (i.e., nifurtimox and benznidazole) that show important limitations for treating patients. In this context, many laboratories look for alternative therapies potentially applicable to the treatment, and therefore, research in CD chemotherapy works in the design of experimental protocols for detecting molecules with activity against T. cruzi. Phenotypic assays are considered the most valuable strategy for screening these antiparasitic compounds. Among them, in vitro experiments are the first step to test potential anti-T. cruzi drugs directly on the different parasite forms (i.e., epimastigotes, trypomastigotes, and amastigotes) and to detect cytotoxicity. Once the putative trypanocidal drug has been identified in vitro, it must be moved to in vivo models of T. cruzi infection, to explore (i) acute toxicity, (ii) efficacy during the acute infection, and (iii) efficacy in the chronic disease. Moreover, in silico approaches for predicting activity have emerged as a supporting tool for drug screening procedures. Accordingly, this work reviews those in vitro, in vivo, and in silico methods that have been routinely applied during the last decades, aiming to discover trypanocidal compounds that contribute to developing more effective CD treatments. Keywords Chagas disease . Trypanosoma cruzi . Experimental chemotherapy . In vitro . In vivo . In silico Introduction Chagas disease (CD), also known as American trypanosomi- asis, is a parasitic infection caused by the kinetoplastid proto- zoan Trypanosoma cruzi, which is naturally transmitted by the contaminated feces of hematophagous triatomine bugs of the family Reduviidae. This parasitosis, classified by the WHO as one of the 20 Neglected Tropical Diseases, is endemic in 21 Latin American countries, where it mostly affects the poorest people in rural areas, provokes more than 7000 deaths per year, and maintains over 25 million people at risk of the in- fection (WHO 2015; 2017). However, in recent decades, the disease has also emerged in nonendemic countries (e.g., USA, Australia, Japan, and Spain), as a result of the intense popula- tion mobility and the existence of alternative routes of trans- mission, such as transfusions of infected blood, contaminated organ transplantation, or mother to child (Gascón et al. 2010). In fact, it is estimated that between 68,000 and 123,000 people infected by T. cruzi live in Europe, mainly in Spain, whereas the number of chagasic patients reaches about 300,000 in the USA (Pinazo and Gascón 2015). This epidemiological situa- tion has turned CD into a global public health problem that currently affects about six to seven million individuals and puts an estimated 75 million people worldwide at risk (WHO 2017). The clinical evolution of the disease involves an acute phase that normally appears 1 week after the initial infection. In the majority of cases, the acute disease is asymptomatic or oligosymptomatic and the nonspecific clinical manifestations resolve spontaneously in 90% of infected individuals (Dubner et al. 2008; Rassi Jr et al. 2010). In the case of vector-borne transmissions, a local inflammation can be observed at the site Section Editor: Kevin S.W. Tan * Cristina Fonseca-Berzal crfonseca@pdi.ucm.es 1 Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Pza. Ramón y Cajal s/n, 28040 Madrid, Spain 2 Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), c/ Juan de la Cierva 3, 28006 Madrid, Spain Parasitology Research https://doi.org/10.1007/s00436-018-6084-3