Modelling inter-human transmission dynamics of Chagas disease: analysis and application

Calculating epidemiological measures of infection by Trypanosoma cruzi, the causative agent of Chagas disease, is complex, because it involves several species, different stages of infection in humans and multiple transmission routes. Using the next-generation matrix method, we analysed a model which considers the three stages of human infection, triatomines and dogs (the main domestic reservoirs of T. cruzi when triatomines are present) and the main transmission routes. We derived R 0 and type-reproduction numbers T. We deduced formulas for the number of new infections generated through each transmission route by each infected individual. We applied our findings in Argentine Gran Chaco. The expressions achieved allowed quantifying the high infectivity of dogs and emphasizing the epidemiological importance of the long and asymptomatic chronic indeterminate stage in humans in the spread of the infection. According to the model, it is expected that one infected human infects 21 triatomines, that 100 infected triatomines are necessary to infect one human and 34 to infect a dog, and that each dog infects on average one triatomine per day. Our results may allow quantifying the effect of control measures on infected humans, triatomines and dogs (or other highly infected vertebrate) or on a specific route of transmission, in other scenarios.

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“…The importance of HI individuals has also been shown in our previous work in a triatomine-free scenario (Fabrizio et al . 2014 b ).…”

Section: Discussionmentioning

confidence: 99%

“…In a previous paper (Fabrizio et al . 2014 b ), we presented a model of the so-called urban Chagas , i.e. Chagas disease in a triatomine-free scenario.…”

Section: Discussionmentioning

confidence: 99%

Analysis of the transmission ofTrypanosoma cruziinfection through hosts and vectors

2016

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“…In endemic countries, Chagas disease is primarily transmitted by triatomine vectors, predominantly in rural areas. However, human migration and other forms of transmission have changed the epidemiology/epizootiology of Chagas disease, which is currently affecting peri-urban and urban areas ( 5 , 6 ). Other important mechanisms of transmission include blood transfusion, organ transplants, oral ingestion, laboratory accidents, vertical transmission from mother to child, or needle sharing ( 2 , 7 ).…”

Section: Introductionmentioning

confidence: 99%

Is It Possible to Intervene in the Capacity of Trypanosoma cruzi to Elicit and Evade the Complement System?

et al. 2021

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Chagas’ disease is a zoonotic parasitic ailment now affecting more than 6 million people, mainly in Latin America. Its agent, the protozoan Trypanosoma cruzi, is primarily transmitted by endemic hematophagous triatomine insects. Transplacental transmission is also important and a main source for the emerging global expansion of this disease. In the host, the parasite undergoes intra (amastigotes) and extracellular infective (trypomastigotes) stages, both eliciting complex immune responses that, in about 70% of the cases, culminate in permanent immunity, concomitant with the asymptomatic presence of the parasite. The remaining 30% of those infected individuals will develop a syndrome, with variable pathological effects on the circulatory, nervous, and digestive systems. Herein, we review an important number of T. cruzi molecules, mainly located on its surface, that have been characterized as immunogenic and protective in various experimental setups. We also discuss a variety of parasite strategies to evade the complement system - mediated immune responses. Within this context, we also discuss the capacity of the T. cruzi infective trypomastigote to translocate the ER-resident chaperone calreticulin to its surface as a key evasive strategy. Herein, it is described that T. cruzi calreticulin inhibits the initial stages of activation of the host complement system, with obvious benefits for the parasite. Finally, we speculate on the possibility to experimentally intervene in the interaction of calreticulin and other T. cruzi molecules that interact with the complement system; thus resulting in significant inhibition of T. cruzi infectivity.

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“…Increasing numbers of patients detected by routine screenings of blood banks or organ banks in the USA led to the implementation, in early 2007, of the first diagnostic test for Chagas disease approved by the Food and Drug Administration for use in the USA [ 7 ]. It has been suggested that around 94% of new infections of urban Chagas occur from subjects with the indeterminate or chronic asymptomatic chagasic form (ICF) [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Early Detection of Chronic Asymptomatic Chagas Infection

et al. 2018

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Chagas disease, also known as American trypanosomiasis, is a chronic and systemic parasitic infection which has become a serious epidemiological problem not only in endemic regions (Latin America), but also in non-endemic ones like North America, Europe, and Oceania. Subjects with the indeterminate chagasic form (ICF), a chronic asymptomatic disease stage, are the main sources of non-vectorial dissemination through blood transfusion, organ transplantation, and congenital transmission. It has been suggested that 94% of urban infections can be explained by these subjects. Under this scenario, the availability of simple and effective screening methods for ICF detection becomes crucial for both prevention of disease propagation and detection of clinical stages. Recently, a new non-invasive method has been proposed for ICF detection. It is based on surface high-resolution ECG and it could be easily adopted and included in modern ECG devices, overcoming the limitations of serological-based tests. The proposed method shows accuracy for early ICF screening, thus improving prognosis by defining the clinical stages and allowing appropriate and effective treatment.

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Modelling inter-human transmission dynamics of Chagas disease: analysis and application

Cited by 12 publications

References 37 publications

Analysis of the transmission ofTrypanosoma cruziinfection through hosts and vectors

Analysis of the transmission ofTrypanosoma cruziinfection through hosts and vectors

Is It Possible to Intervene in the Capacity of Trypanosoma cruzi to Elicit and Evade the Complement System?

Early Detection of Chronic Asymptomatic Chagas Infection

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