Digestive parasitic diseases are diseases caused by the presence of a parasite in the digestive tract. We can contract them when traveling in tropical regions, but also in our latitudes.

Digestive parasitic diseases result from infestation of the intestine or the liver by a worm or an amoeba. While it is difficult to establish an exhaustive list, the most frequently diagnosed in France are as follows.

Pinworm

It is caused by small worms called pinworms. These worms mate in the intestine, then the females join the anus to deposit their eggs. This is what explains the anal itching experienced by patients. Children, who tend to put their hands to their mouths even after scratching their buttocks, easily self-infest and frequently contaminate those around them;

Queen conch, also called giardiasis or giardiasis

It is common, especially in hot and humid regions. Queen Conch is caused by a single-celled parasite that multiplies in the small intestine. This can cause the symptoms of a “turista”: abdominal pain, associated with pasty stools or even diarrhea.

The ascaridose

This is due to the presence of roundworms, pinkish white worms that can measure up to 20 cm long. They are more prevalent in tropical areas, where travelers can swallow their eggs on soiled food. 

Pathology, when it manifests itself, begins with a persistent cough. Indeed, the ingested eggs release larvae which will cross the intestinal wall to reach the lungs, where they carry out the first phase of their development. It is only after a fortnight that they go up the respiratory tract to the pharynx, to descend into the digestive tract. They then become adults, and can remain in the intestine for several months, causing digestive disorders. 

In rare cases, the symptoms are more severe: intestinal obstruction, acute pancreatitis, etc.

Tæniasis

Caused by a tapeworm, the tapeworm, also called a “tapeworm”. It is ingested in undercooked infested meat. Veterinary checks in slaughterhouses and the tradition of cooking pork meat well have reduced the spread of this disease in France, but have not completely eliminated it. 

Firmly anchored to the intestinal wall, the tapeworm grows to be composed of thousands of rings, some of which break off regularly. It can live for several decades in the intestine, without necessarily making you sick. Appetite disturbances, associated with rapid weight loss, may nevertheless appear;

Human cysticercosis

Caused also by the tapeworm, it is more serious, because the parasite settles this time on the level of the muscles or the nervous system. This can cause severe neurological (epilepsy) or eye disorders (retinal detachment, hemorrhage or even glaucoma). Cases are rare but require immediate treatment.

Hydatidosis, also called hydatid echinococcosis. 

It is caused by a worm, Echiococcus granulosus, which usually affects dogs, cats and foxes, but whose eggs can be accidentally ingested by humans (after petting an infested animal, for example). It is mainly found in South America, Australia and the Mediterranean basin, including in south-eastern France and Corsica. Once ingested, the eggs release larvae in the intestines which pass through the digestive wall to settle in the liver or the lungs. They will possibly multiply there and become pathogenic.

Amebiasis, or amoebosis

Uncommon in France. It is caused by amoebae that get caught through soiled hands or poorly washed food. These amoebae can invade and attack the intestinal wall, or even spread throughout the body, until they are fixed in other organs such as the liver or the lungs. Symptoms can be serious (hepatitis, lung damage, etc.).

We can also cite, even if they are rarer in France, tropical and subtropical diseases such as hookworm, bilharzia (also called schistosomiasis) or anguillulosis. The parasites in question enter the body through the skin, when walking barefoot in contaminated soil or stagnant water. Symptoms (abdominal pain, anemia, etc.) often appear after returning from a trip.

It depends on the parasite. In France, where drinking water and sanitation networks are well developed, the main source of contamination is related to stool. Unwashed hands after using the toilet can contaminate the environment, and dirty hands put in the mouth can encourage the ingestion of parasites. 

In less developed countries, especially if they are located in hot and humid regions, favorable to the development of parasites, the latter can be present in tap water or on the skin of raw vegetables. It is therefore better to respect the recommendations made to travelers who go to these areas: 

• avoid eating raw foods if they do not peel;
• avoid drinking unboiled tap water;
• make sure the meat is well cooked;
• wash hands before meals;
• Before swimming in stagnant water, it is also better to learn about the risks of contracting a parasite there.

Again, it depends on the parasites. Symptoms can be: 

• anal pruritus : associated with irritability and sleep disturbances, especially in children, this strong urge to scratch is very suggestive of pinworm infection; 
• the presence of white rings in the stool, underwear or the bottom of the shower : these rings, 1 cm long and a few millimeters wide, are those of the tapeworm;
• intestinal disorders : abdominal pain, diarrhea, nausea, vomiting, constipation, etc. They should worry you if they persist or if it is profuse diarrhea with loss of blood and phlegm;
• appetite disturbances (anorexia, bulimia), leading to rapid weight loss;
• lung damage : persistent cough, difficulty in breathing, unusual sputum, etc.

This can be associated with fever, fatigue, headaches or rashes. Some parasitoses can have more severe complications:

• intestinal obstruction or perforation;
• angiocholite;
• acute pancreatitis;
• hepatitis;
• epilepsy;
• retinal detachment;
• allergic reaction ;
• etc.

But these cases, which lead to prompt consultation, are very rare.

If you see a doctor, remember to report trips made in the past few months. This can help guide the diagnosis.

Confirmation of the diagnosis

The final diagnosis is most often based on a stool analysis, carried out several days in a row so that the result is not distorted by so-called “silent” periods, without egg production. A blood test may also be ordered.

In the case of pinworm, the method of choice for the diagnosis remains the “scotch test”: in the morning, preferably before washing, a fragment of transparent adhesive tape is applied to the folds of the anus previously unfolded. This tape will then be stuck on a slide to be examined under a microscope.

Most of the pathologies mentioned above are treated with medication. If the pathology is contagious, particularly in cases of pinworm infection, the treatment is also prescribed to other people living with the patient.

Certain pathologies, more rare, require surgical treatment, to eradicate the parasite or drain an infected organ. This is the case, for example, in the case of cysticercosis, hydatidosis or amoebiasis.