[Myocarditis caused by Trichinella spiralis: a case report]

Identification and profiling of Trichinella spiralis circulating antigens and proteins in sera of mice with trichinellosis

Trichinellosis is a zoonotic disease caused by the ingestion of the Trichinella nematode. With a worldwide incidence of approximately 10,000 cases per year, Trichinella spiralis is responsible for most human infections. There are no specific signs or symptoms of this parasitic infection. Muscle biopsy is the gold diagnostic standard for trichinellosis, but the technique is invasive and unable to detect the early stage of infection. Although immunodiagnostics are also available, antibody detection usually occurs after 3 weeks and prolonged up to 19 years after the acute phase. Therefore, additional diagnostic biomarkers must be identified to improve trichinellosis diagnosis. This study aimed to measure concentration changes in mouse serum proteins prior to T. spiralis infection and 2, 4 and 8 weeks after infection, and to identify T. spiralis circulating proteins and antigens using mass spectrometry-based proteomics. Mouse muscle-related proteins including inter-alpha-trypsin inhibitor heavy chain H2, a protein involved in the response to muscle tissue damage, were up-regulated in mouse sera during the T. spiralis larvae invasion. Additionally, 33 circulatory parasite proteins were identified in infected mouse sera. Notably, T. spiralis long-chain fatty acid transport protein 1 could be detected in the early stage of infection and peroxidasin-like protein was identified 2, 4 and 8 weeks after infection. Seventeen T. spiralis circulating antigens were detected in mouse immune complexes, with PX domain protein being found 2, 4 and 8 weeks after infection. Because peroxidasin-like protein and PX domain protein were detected at all post-infection time points, sequence alignments of these proteins were performed, which showed they are conserved among Trichinella spp. and have less similarity to the human and murine sequences. Integrative analysis of T. spiralis biomarkers throughout the course of infection may reveal additional diagnostic targets to improve early diagnosis of trichinellosis.

Trichinella spiralis-associated myocarditis mimicking acute myocardial infarction

BACKGROUND

Trichinellosis is a parasitic infection caused by nematodes of the genus Trichinella, and its principal mode of transmission is the consumption of raw or undercooked contaminated meat. Cardiac involvement in trichinellosis is unusual, yet it represents the most frequent cause of death. Here, we report a case in which Trichinella spiralis-associated myocarditis simulated a myocardial infarction.

CASE PRESENTATION

A 35-year-old African man with no previous medical history was admitted to the emergency department for acute substernal discomfort at rest described as a pressure with no radiation. The electrocardiogram performed upon admission showed non-specific alterations of repolarization. Blood biology revealed high levels of troponin T and predominant eosinophilic leukocytosis. A transthoracic echocardiography was carried out and found a significant left ventricular concentric hypertrophy with a preserved ejection fraction. The septal and inferior walls, as well as the endocardium were hyperechogenic. The patient was hospitalized for eosinophilic myocarditis. The cause of hypereosinophilia was investigated, and a Trichinella spiralis serology came back strongly positive. A diagnosis of Trichinella spiralis associated-myocarditis was made.The patient was treated with albendazole-prednisolone dual therapy with favorable clinical and biological outcomes.

CONCLUSION

The clinical suspicion of trichinellosis is based on suggestive epidemiology associated with the typical clinical presentation and the presence of eosinophilia. Eosinophilic myocarditis is a severe complication of trichinellosis which can result in death due to rhythm disorders. Chest pain, increase in troponins, and electrocardiographic abnormalities are all elements that can mimic a myocardial infarction and mislead clinicians.Abbreviations: ANCA: Anti-Neutrophil Cytoplasmic Antibodies; ANA: Anti-Nuclear Antibodies; ECDC: European Centre for Disease Prevention and Control; ECG: Electrocardiogram; ELISA: Enzyme-Linked ImmunoSorbent Assay; EMF: Endomyocardial Fibrosis; ES: Excretory-Secretory; ICT: International Commission on Trichinellosis; MRI: Magnetic Resonance Imaging.

Cardiac involvement with parasitic infections

Parasitic infections previously seen only in developing tropical settings can be currently diagnosed worldwide due to travel and population migration. Some parasites may directly or indirectly affect various anatomical structures of the heart, with infections manifested as myocarditis, pericarditis, pancarditis, or pulmonary hypertension. Thus, it has become quite relevant for clinicians in developed settings to consider parasitic infections in the differential diagnosis of myocardial and pericardial disease anywhere around the globe. Chagas' disease is by far the most important parasitic infection of the heart and one that it is currently considered a global parasitic infection due to the growing migration of populations from areas where these infections are highly endemic to settings where they are not endemic. Current advances in the treatment of African trypanosomiasis offer hope to prevent not only the neurological complications but also the frequently identified cardiac manifestations of this life-threatening parasitic infection. The lack of effective vaccines, optimal chemoprophylaxis, or evidence-based pharmacological therapies to control many of the parasitic diseases of the heart, in particular Chagas' disease, makes this disease one of the most important public health challenges of our time.