Food Safety and Foodborne Trematodiases: What You Need to Know

 Food Safety and Foodborne Trematodiases: What You Need to Know

In public health, food safety is an essential aspect of disease prevention and population well-being. While everyone knows such easily recognizable foodborne diseases as salmonella or E. coli, fewer know about foodborne trematodiases—a category of parasitic diseases, which are becoming increasingly important because of shifts in eating habits, globalization, and environmental factors.

This blog delves into what foodborne trematodiases are, how they are transmitted, the dangers they present, and how we can avoid them through improved food safety measures.

What are Foodborne Trematodiases?

Foodborne trematodiases are a collection of parasitic flatworm infections caused by trematodes (also known as flukes). Trematode larvae-contaminated raw or undercooked freshwater fish, crabs, or aquatic plants infect humans.

The principal foodborne trematodiases of humans are:

Clonorchiasis (infected by Clonorchis sinensis)

Opisthorchiasis (infected by Opisthorchis viverrini and Opisthorchis felineus)

Fascioliasis (infected by Fasciola hepatica and Fasciola gigantica)

Paragonimiasis (infected by Paragonimus species)

These infections are neglected tropical diseases (NTDs), which means they commonly infect poor and marginalized communities and have less priority compared to other infectious diseases.

How Do People Get Infected?

Trematodes have intricate life cycles that typically include two or more hosts. The cycle is usually initiated in a freshwater habitat, where eggs of the parasite are released by way of feces from infected humans or animals into sources of water. The following is how the transmission usually occurs:

Eggs hatch in fresh water and discharge larvae (miracidia), which infect snails—the first intermediate host.

Within the snail, larvae grow and multiply, then exit as free-swimming cercariae.

These cercariae infect second intermediate hosts, such as fish, crabs, or aquatic plants, encysting as metacercariae.

Humans are infected by eating raw or undercooked intermediate hosts harboring the metacercariae.

Within the human body, the larvae become adult flukes and inhabit organs such as the liver, lungs, or intestines, leading to long-term chronic infections and severe complications.

Geographical Distribution and Burden

Foodborne trematodiases are most common in regions of:

Asia: Particularly Southeast Asia (Thailand, Vietnam, Laos, Cambodia, China, and Korea)

Africa

Latin America

The World Health Organization (WHO) reports that more than 56 million individuals worldwide are infected with foodborne trematodes and over 750 million are at risk, primarily because of poor sanitation and unsafe food handling practices.

Symptoms and Health Impact

The signs of foodborne trematodiases are dependent on the species of trematode and the organs involved. Infections are usually asymptomatic in the initial stages, but eventually develop into significant morbidity.

Typical symptoms are:

Abdominal pain

Diarrhea

Fatigue

Fever

Jaundice

Coughing (in paragonimiasis)

Enlargement of the liver

Severe long-term sequelae can be:

Obstruction of bile ducts

Liver fibrosis

Gallbladder cancer (especially in Opisthorchis infection)

Malnutrition

Respiratory problems

In most instances, these conditions are debilitating and chronic, decreasing quality of life and productivity, particularly in already disadvantaged populations.

Diagnosis and Treatment

Diagnosis is most commonly established by:

Microscopic stool exam for eggs of the parasites

Serology tests

Imaging studies (ultrasound, CT scan) for visceral involvement

Treatment is generally with antiparasitic drugs such as:

Praziquantel (effective for the majority of trematodes)

Triclabendazole (drug of choice in Fasciola infestation)

Early treatment and detection are important for avoiding complications, but healthcare access is limited in most endemic countries.

Why Food Safety Is Important

The main mode of infection is food—thus food safety is the first line of defense against trematodiases.

unsafe food handling habits responsible for transmission include:

Consumption of raw or not fully cooked freshwater fish (e.g., sushi, sashimi, ceviche)

Drinking unwashed aquatic vegetation such as watercress

Poor hygiene when handling and preparing food

Contamination of water bodies used for irrigation and washing of food

Minimizing transmission and ensuring public health can be greatly achieved by enhancing food safety.

Preventive Measures

1. Cook Food Thoroughly

Make sure all freshwater fish, crabs, and aquatic plants are thoroughly cooked to safe internal temperatures. Do not consume dishes using raw or undercooked food from potentially infected water bodies.

2. Wash Produce Properly

Properly wash vegetables, particularly aquatic plants, prior to consumption. Clean and safe water must be used when washing.

3. Enhance Sanitation

Avoiding contamination of water sources with human or animal feces is essential. This includes:

Construction and maintenance of latrines

Safe disposal of sewage

Education of communities in hygiene

4. Public Awareness

Public education campaigns may enable individuals to appreciate the risk involved in specific traditional food practices and adopt safe alternatives.

5. Veterinary and Agricultural Control

Because several trematodes infect animals as well, integrated control with veterinary services is essential. The monitoring and treatment of livestock, and strict aquaculture practices to keep waters clean, help to decrease cross-species transmission risk.

Global Response and Future Outlook

The World Health Organization has placed foodborne trematodiases in its roadmap for neglected tropical diseases, aiming to decrease morbidity by 2030. These include:

Strengthening surveillance systems

Enhancing access to diagnostics and treatment

Promoting intersectoral collaboration (health, agriculture, education)

But to fight foodborne trematodiases, community involvement, government support, and international attention—particularly as global food trade and travel continue to grow—are needed.

Conclusion

Foodborne trematodiases are a silent but potent public health threat, particularly where cultural food habits coincide with unsanitary conditions. Through prioritizing food safety, enhancing hygiene, and increasing awareness, we can alleviate the impact of these illnesses.

Whether you are a consumer, food handler, or policymaker, you are part of the solution to preventing these infections. Safe food, after all, is not a luxury—it's a human right.