What Is Trichinosis?

What is trichinosis, and what can be done to prevent this parasitic condition from afflicting us? Let us take a look into the nature of this disease, cures and how to avoid it.

Description and background

Trichinosis also known as trichinellosis is defined as a parasitic infection, mainly connected to the wrongful preparation of food containing pork or its byproducts.

This infection is mostly present in countries with high pork consumption, where it becomes a very frequent public health issue1; it is estimated that about ten thousand people become infected each year with this parasite.²

Transmission and causes

This food-related disease is caused by a parasite called Trichinella, a type of roundworm classified as a nematode. This parasite can be hosted not only by humans but also by domestic and wild animals, involving more than 150 species. While this condition most frequently occurs because of the consumption of raw or uncooked pork, horse or wild game (such as bear, wild feline, fox, dog, wolf and many others) can also cause trichinosis when infected by Trichinella.
These parasite larvae are usually contained in cysts attached to the muscles of the infected animal, these cysts open in the intestines releasing the larvae, and, allowing them to grow into adult roundworms. Grown into adults female roundworms lay eggs, these eggs become larvae that migrate through the bloodstream to the muscles and enclose in cysts starting the cycle back again. 
It is important to note that trichinosis can only be transmitted through undercooked meat consumption and that person-to-person transmission does not occur, however even very small amounts of uncooked meat can lead to infection.³

Symptoms

What are the early signs of infection?

The early phase of this condition is mainly asymptomatic, however it can be associated with abdominal pain, diarrhoea and vomiting, these symptoms can appear 2 to 7 days after infection.

Later signs and possible complications

The main symptoms of the disease usually appear 1-2 weeks after consumption and can last up to 8 weeks, these symptoms can involve fevers, muscle pain, swelling around face and/or eyes, weakness, fatigue and chills. Less common symptoms can involve chronic diarrhoea, eye conditions such as conjunctivitis and subconjunctival haemorrhages (breakage of tiny blood vessels in the eyes), and minor symptoms like headache, cough, rash, shortness of breath, and difficulty in swallowing.⁴
In case of severe infection, serious complications can lead to myocarditis (inflammation of the heart membrane), life-threatening arrhythmias (irregular heartbeat), meningitis (inflammation of the tissue surrounding the brain), encephalitis (inflammation of the brain), respiratory myositis (inflammation of breathing muscles), bacterial pneumonia, hematuria (blood in urine), and renal failure. The severity of symptoms is usually related to the number of ingested larvae.⁵

Diagnosis

Trichinosis can be diagnosed by clinical signs and symptoms of the disease, laboratory investigations related to antibody detection and muscle biopsy (to detect larvae in muscles). Epidemiological investigations can also be helpful to identify a possible source of infection.⁶

Primary laboratory tests

• Muscle biopsy - the removal of a small muscle tissue sample to detect the presence of this parasite
• Blood tests or Serologic tests - ELISA (Enzyme-linked immunosorbent assay) and western blot are both suggested tests; the former can help detect antibodies indicating the presence of Trichinella, and the latter identifies specific proteins which can help identify the presence of Trichinella specific antibodies.

These two tests are considered crucial for the accurate diagnosis of this condition; other tests can be used as additional testing to add supporting information regarding the patient’s condition.

Additional procedures

• Urinalysis (UA)
• Stool sample analysis

Both urinalysis and stool sample analysis can provide additional information regarding this condition. These tests are considered supplementary and can further confirm the diagnosis and highlight potential complications in the kidneys.

Imaging investigation

• X-ray of the extremities of the limbs
• Magnetic resonance imaging (MRI) of the brain
• Computerized tomographic (CT) scanning of the brain

X-ray, CT and MRI scans are not essential in the diagnosis of trichinosis; however, these tests can provide useful information in case of suspected muscle inflammation, abnormality and complications related to Trichinella infection.

Treatment

Treatment should start immediately after confirmed infection, antiparasitc drugs such as mebendazole or albendazole are the most used. These two antiparasitic drugs can prevent worsening of the infection by killing adult Trichinella roundworms, and prevent further reproduction and spread of the infection.

Treatment should start within the first days of infection to prevent the infection from becoming more persistent and consequentially needing repeated courses of treatment, which could lead to more serious complications.⁷

This course of treatment is considered safe. However, patients can experience side effects related to the drug, such as nausea, vomiting, stomach pain and diarrhoea. In more severe cases, steroid treatment might be required, and steroids might be used in case of allergic reactions caused by trichinosis. This reaction might be caused by the parasites entering the muscles or by the death of the parasite releasing chemicals. Steroids are used to control and reduce pain and swelling. Patients might also be prescribed pain medication, as the entrance of the larvae into the muscles might cause aching and swelling.⁸

Prevention

Prevention is considered one of the main factors in reducing the risk of trichinosis.

To prevent infection, meat should be cooked to safe temperatures, and the right food safety measures should be adopted.⁹

• Meat should be cooked above 70°C or 160°F
• Salting, smoking, drying and microwaving of meat does not kill this parasite and should not be used when uncertain about the meat's safety.
• Freezing meat for a minimum of 20 days at -15°C or 5°F can kill Trichinella in pork. However, this technique does not work for wild game meat.
• Any utensil used during raw meat preparation should be thoroughly washed after use to prevent cross-contamination
• Handwashing with water and soap after raw meat handling is essential
• Knowing the meat source and buying from trusted suppliers can minimize the chance of Trichinella contamination

Conclusion

richinosis is caused by the Trichinella parasite, it is a serious food-related illness primarily linked to the consumption of undercooked pork, horse, and wild game meats. Confirming the infection early through clinical examinations and laboratory assessments is essential for successful treatment, and a rapid administration of antiparasitic medications is crucial in lowering the intensity of the disease and decreasing potential complications.

Additionally, preventive measures, including safe meat cooking procedures and adherence to food safety guidelines, play a leading role in controlling the prevalence of trichinosis.

If you suspect you or any of your family members have come into contact with this parasite, and show any symptoms make sure to contact your healthcare provider to know how to proceed.

Summary

• Trichinosis comes from eating not fully cooked pork or wild game meat.
• Trichinella is the main cause of trichinosis.
• Even small amounts of infected meat (i.e. tasting) can result in trichinosis.
• Doctors can make an early diagnosis by doing tests and checking for the parasite.
• Using antiparasitic drugs can significantly improve this condition when used early.
• Cooking your meat the right way and being careful with how you handle it can stop you from getting sick. Following these rules can help keep you and your family healthy.

FAQs

Can trichinosis be cured?

Trichinosis can be treated with antiparasitic drugs when identified rapidly, however when larvae enter the muscle it can only be managed with pain relievers, and can last several years.

What are the risk factors for trichinella?

The risk factors are improper food preparation, as Trichinella can be contracted through undercooked pork or wild animal meat and contaminated kitchen equipment.

Another important risk factor is location, as trichinosis is more common in rural areas.

Consumption of wild meat, or non-commercial meat, also shows a higher risk of infection compared to commercial and controlled meat.

Can trichinella go away on its own?

Trichinella can heal on its own, however it can take several years for this to happen and the condition can worsen over time when not managed properly. Trichinosis is highly influenced by the number of larvae, a lower number results in some symptoms disappearing within the first few months, however several symptoms may remain several years.

How likely are you to get trichinosis from pork?

The risk of infection from commercial pork meat, when raised and prepared properly is very low, however, undercooked wild game can put you at risk of contracting the disease.