Introduction

Humans, domestic and wild animals can contract trichinellosis (also known as trichinosis), a zoonosis caused by roundworms of the genus Trichinella. Horses, domestic pigs, bears, rodents, and wild boars represent reservoir animals for the parasites.¹ Eating undercooked or uncooked meat that contains the roundworm's larvae (an immature stage) can infect you.² Trichinella species promote human trichinellosis in a large portion of the world. This disease threatens public health since it affects humans and also poses a financial challenge to the production of pigs and food safety. In many nations, the primary focus is to control or remove Trichinella from the food chain due to the infection's primarily zoonotic significance.⁵ Although agricultural pigs are the main conduit of human infection globally, horse and wild boar meats have been implicated in outbreaks in Europe during the last three decades. It is unclear whether the lowest contagious dose engenders illness in people. According to Dupouy-Camet and Bruschi, between 100 and 300 Trichinella spiralis larvae begin to cause illness, and an intake of 1,000 to 3,000 or more larvae results in severe illness. However, this estimate was not supported by scientific data, thus it’s unreliable.⁵ Symptomatic myocarditis is a rare side effect of trichinosis which is frequently linked to higher morbidity and death.⁴

Inflammation of the myocardium, the heart muscle, is known as myocarditis. The illness may make it harder for the heart to pump blood. Breathlessness, fast or erratic heartbeats, and chest pain are all symptoms of myocarditis.³ Most myocarditis cases (65%) are acute myocarditis, which is commonly caused by a viral infection, and nearly by non-infectious causes. The myocardium may be diffusely involved or focally involved.⁹

Before expanded research studies recently demonstrated myocarditis's true epidemiological significance, it was considered a rare disease. Although unravelling the actual prevalence of myocarditis remains difficult, research is currently in progress to more accurate estimates of the disease's proportions.⁶ These days, myocarditis is expected to affect 1.8 million people annually, with prevalence ranging from 10.2 to 105.6 cases per 100,000 people worldwide. The uncertainties surrounding the disease's actual prevalence and possible underdiagnoses are reflected in the broad range of reported cases. Better diagnosis and treatment methods are required since myocarditis remains a major public health concern, especially in young adults, where it is one of the leading causes of fatal cardiac arrest.⁶ Understanding the link between trichinosis and myocarditis is critical for early diagnosis, adequate care, and improved patient outcomes. This study covers the pathogenesis, evaluation, therapy, and prevention of these two disorders.

Trichinosis: causes, transmission, and pathophysiology

Causative agent

Eating undercooked meat that includes cysts (larvae, or young worms) of Trichinella spiralis can result in trichinosis, a parasitic disease. Pigs, bears, walruses, foxes, rats, horses, and lions are all susceptible to this parasite. Roundworm illness may be spread by wild animals, particularly by carnivores (animals that consume meat) or omnivores (animals that eat both meat and plants).⁷

Lifecycle of Trichinella spiralis

Mammals, birds, and reptiles are among the hosts of Trichinella species, which have a two-generation life cycle. Newborn larvae (NBL), which are delivered by the corpulent female worm, move into the host's blood and lymphatic arteries and enter highly oxygenated muscles. NBL can persist in muscle nurse cells for years; however, after a while, calcification of the collagen capsule, nurse cell, and larva may happen due to host impact.⁵ Once gastric digestion in a new host, the parasite larvae are discharged, and within two days, they mature into the adult form. After males and females copulate, an intestine immune-mediated host response takes hold within a few weeks, compromising the female parasites' ability to survive and leading to the ongoing evacuation of adult worms.⁵

Symptoms of trichinosis

The severity of a trichomoniasis illness varies according to the body's parasite count. While mild or persistent infestations can result in severe symptoms, mild cases might not exhibit any. Initial symptoms include nausea, vomiting, exhaustion, diarrhoea, and stomach discomfort.² Later, mature female worms give birth to larvae that burrow into muscle tissue, resulting in symptoms like swelling, muscle pain, and a high fever. Speech, respiration, and mobility may be restricted by severe symptoms. When larvae develop cysts, symptoms may subside, but they typically persist for several months. Fatigue, moderate pain, weakness, and diarrhoea may last for months or years after the infection has cleared up.² Complications from the uncommon illness trichomoniasis include lung pneumonia, meningitis, brain encephalitis, and myocarditis. Trichinella larvae can have an impact on the brain, heart wall muscle layer, and the protective tissue layer that envelops the brain and spinal cord.⁸

Myocarditis: pathophysiology and symptoms

Pathophysiology

When the virus enters cardiac cells, it triggers both an innate and an adaptive immune response, resulting in acute myocarditis, and an inflammatory cardiomyopathy. Myocardial dilatation and cardiomyopathy are caused by persistent inflammation and remodelling of the myocardium. Interleukin and damage-associated molecular patterns (DAMP) are released when the virus damages cells, which attracts innate immune system inflammatory cells.⁹ Myeloid progenitor cells are released, pro-inflammatory cells are replenished by the spleen, and monocytopoiesis is triggered by stress. Chronic inflammation, cardiac remodelling, and ventricular dysfunction are the results of this heightened inflammatory reaction. Inflammatory myocarditis is influenced by autoimmunity; in more than half of cases, autoantibodies targeting the cardiac myosin chain are detected.⁹

Symptoms of myocarditis

Since myocarditis lacks remarkable symptoms, it can be difficult to diagnose and treat. If myocarditis is suspected, it is vital to consult a doctor right away. Common symptoms comprise shortness of breath, exhaustion, palpitations, chest pain, dizziness, inflammation, and rapid loss of consciousness.⁸

Diagnosis

Trichinosis diagnosis

A medical professional will diagnose trichomoniasis based on symptoms, the presence of larvae in meat, and elevated eosinophil counts in blood testing. Trichinella antibodies are undetected initially, although blood testing may subsequently validate the diagnosis. Stool samples are unrequired, and a biopsy might be suggested in some rare circumstances.⁵

Myocarditis diagnosis

A physical examination, medical history, and procedures like MRI, heart biopsy, PET, chest X-ray, cardiac catheterisation, ECG/EKG, echocardiogram, and blood tests are used to diagnose myocarditis. These tests assist medical professionals in determining whether a patient has myocarditis or another ailment.³

Trichinosis treatment

Anthelmintics, glucocorticosteroids, and treatments to compensate for protein and electrolyte deficiencies are used to treat trichomoniasis, a bacterial illness. Steroids like prednisone and pyrantel are used for severe symptoms, while anthelmintics like albendazole and mebendazole are the main medications for both adult and paediatric patients. Most infected persons are diagnosed weeks after infection, and the success of anthelmintic chemotherapy relies on the time of administration.⁵ Medication should be given for extended periods of time in advanced stages. Since the 1970s, the market for animal health has been completely transformed by the new class of macrocyclic lactones, which are separated into milbemycins and avermectins. The anthelmintic properties of cyclooctadepsipeptides, a naturally occurring molecule from Mycelia sterilia, have also been investigated.⁵

Myocarditis treatment

Supportive care is necessary for the cardiac ailment known as acute myocarditis. It entails controlling arrhythmias, heart failure, and other drugs. The severity and haemodynamic condition of the patient determine how heart failure is managed. In extreme situations, mechanical support systems are utilised, diuretics are administered, and beta-blockers are stopped. For individuals with haemodynamically stable tachyarrhythmias and no evidence of peripheral hypoperfusion, arrhythmia treatment is essential.⁹ Sustained ventricular arrhythmias may be treated with dofetilide and amiodarone. Temporary and permanent pacemakers are used to treat heart block, and in the chronic stage, an implanted cardioverter defibrillator is advised. Antiviral therapy is not recommended, nor should immunosuppressive therapy be used frequently. In the acute situation, non-steroid anti-inflammatory drugs should be avoided. It is advised that patients limit their exercise and refrain from competing in sports for a minimum of three to six months. Only one drink of alcohol is allowed per day.⁹

Summary

Despite being separate illnesses, trichinosis and myocarditis are crucially related when Trichinella larvae infiltrate cardiac muscle and cause inflammatory consequences. Consuming undercooked meat from infected animals is the main way that Trichinella spiralis and similar species spread the zoonotic disease trichinosis. After a lengthy life cycle, the parasite encysts in muscle tissue, where it can have serious systemic consequences, such as myocarditis. Inflammation of the heart muscle, or myocarditis, can cause serious cardiac malfunction, including arrhythmias, heart failure, and in extreme situations, sudden cardiac death. The significance of early detection and timely intervention is underscored by the overlap between these two illnesses.
Clinical evaluation, serological tests, and occasionally muscle biopsy are used to diagnose trichinosis, whereas imaging methods, including echocardiography, MRI, and ECG, are used to diagnose myocarditis. Antiparasitic medications such as albendazole and mebendazole are used to treat trichinosis, whereas supportive care, arrhythmia control, and heart failure treatment are the mainstays of myocarditis treatments. The best way to fight trichinosis is still to use preventative measures, which emphasise safe meat handling, cooking, and inspection procedures. However, to avoid underdiagnosis and improper treatment, myocarditis necessitates greater awareness and better diagnostic methods.
In order to reduce risks and improve treatment approaches, further study and surveillance are necessary given the public health significance of both illnesses. Healthcare professionals can guarantee prompt interventions and lower the rate of death and morbidity linked to trichinosis and myocarditis by comprehending the complex relationship between the two conditions. Preventive interventions, early detection, and deepened knowledge are essential for protecting the health of both humans and animals.