Polymorphisms of the TLR4 gene: Risk factor for chronicity and severity in oral vectorial Chagas disease

Cardiac and Digestive Forms of Chagas Disease: An Update on Pathogenesis, Genetics, and Therapeutic Targets

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi (T. cruzi), is a neglected disease affecting around 6 million people, with no effective antiparasitic drugs or vaccines. About 40% of Chagas disease patients develop symptomatic forms in the chronic phase of infection, chronic Chagas cardiomyopathy (CCC) or digestive forms like megaoesophagus and megacolon, while most infected patients (60%) remain asymptomatic (ASY) in the so-called indeterminate form (IF). CCC is an inflammatory cardiomyopathy that occurs decades after the initial infection. Death results from heart failure or arrhythmia in a subset of CCC patients. Myocardial fibrosis, inflammation, and mitochondrial dysfunction are involved in heart failure and arrhythmia. Survival in CCC is worse than in other cardiomyopathies. Distinct from other cardiomyopathies, CCC displays a helper T-cell type 1 (Th1-T) cell-rich myocarditis with abundant interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) and selectively lower levels of mitochondrial energy metabolism enzymes and high-energy phosphates in the heart. A CD8+ T cell-rich inflammatory infiltrate has also been found in the Chagasic megaesophagus, which is associated with denervation of myoenteric plexi. IFN-γ and TNF-α signaling, which are constitutively upregulated in Chagas disease patients, negatively affect mitochondrial function and adenosine 5'-triphosphate (ATP) production-cytokine-induced mitochondrial dysfunction. In addition, the differential susceptibility to developing CCC has prompted many studies over the past 25 years on the association of genetic polymorphisms with disease outcomes. A comprehensive understanding of Chagas disease pathogenesis is crucial for identifying potential therapeutic targets. Genetic studies may offer valuable insights into factors with prognostic significance. In this review, we present an updated perspective on the pathogenesis and genetic factors associated with Chagas disease, emphasizing key studies that elucidate the differential progression of patients to CCC and other symptomatic forms. Furthermore, we explore the interplay between genetic susceptibility, inflammatory cytokines, mitochondrial dysfunction and discuss emerging therapeutic targets.

Oral Chagas Disease in Colombia-Confirmed and Suspected Routes of Transmission

Chagas disease (CD) remains endemic throughout many regions of Colombia despite implementing decades of vector control strategies in several departments. Some regions have had a significant decrease in vectorial transmission, but the oral ingestion of Trypanosoma cruzi through consumption of contaminated food and drink products is increasingly described. This form of transmission has important public health relevance in Colombia due to an increase in reported acute CD cases and clinical manifestations that often lead to significant morbidity and mortality. Oral CD in Colombia has been associated with the consumption of contaminated fruit juices, such as palm wine, sugar cane, or tangerine juice and water for consumption, or contaminated surfaces where food has been prepared. Another interesting route of oral transmission includes ingestion of unbeknownst infected armadillos' blood, which is related to a traditional medicine practice in Colombia. Some earlier reports have also implemented consumption of infected bush meat as a source, but this is still being debated. Within the Amazon Basin, oral transmission is now considered the principal cause of acute CD in these regions. Furthermore, new cases of acute CD are now being seen in departments where CD has not been documented, and triatomine vectors are not naturally found, thus raising suspicion for oral transmission. The oral CD could also be considered a food-borne zoonosis, and odoriferous didelphid secretions have been implemented in contaminating the human dwelling environment, increasing the risk of consumption of infectious metacyclic trypomastigotes. In this article, we will discuss the complex transmission dynamics of oral CD in Colombia and further examine the unique clinical manifestations of this route of infection. New insights into the oral transmission of Trypanosoma cruzi are being discovered in Colombia, which can help bring increased awareness and a better understanding of this neglected tropical disease to reduce the burden of CD throughout Latin America.

A Review on the Immunological Response against Trypanosoma cruzi

Chagas disease is a chronic systemic infection transmitted by Trypanosoma cruzi. Its life cycle consists of different stages in vector insects and host mammals. Trypanosoma cruzi strains cause different clinical manifestations of Chagas disease alongside geographic differences in morbidity and mortality. Natural killer cells provide the cytokine interferon-gamma in the initial phases of T. cruzi infection. Phagocytes secrete cytokines that promote inflammation and activation of other cells involved in defence. Dendritic cells, monocytes and macrophages modulate the adaptive immune response, and B lymphocytes activate an effective humoral immune response to T. cruzi. This review focuses on the main immune mechanisms acting during T. cruzi infection, on the strategies activated by the pathogen against the host cells, on the processes involved in inflammasome and virulence factors and on the new strategies for preventing, controlling and treating this disease.