This 43-year-old man, who worked as a PA for a wealthy family, presented with an unusual history.
His job involved travelling in Europe and South-East Asia. During a recent trip to Spain, he noticed a worm in his bowel motion. He had been astonished to find that the worm was nearly 1m long. The patient was clearly distressed and internet research had heightened his anxiety.
It seemed likely that he had picked up a tapeworm infestation when travelling in South-East Asia some months previously.
I arranged a stool sample, which did not show any segments, and FBC, which was normal. LFTs showed no abnormality. The patient was asymptomatic.
The patient was referred to an infectious diseases consultant. After taking a detailed history and reviewing the investigations requested in primary care, the consultant asked the patient to draw the parasite, and made the final diagnosis on the basis of this information. The patient's partner also had stool sample, FBC and LFTs to ensure the infestation had not been passed on by food preparation and cross-contamination. The partner was in the clear and the patient was prescribed antiprotozoal treatment and advised to have follow-up stool samples.
Tapeworm life cycle
Tapeworms are parasites that commonly occur in South-East Asia, parts of southern Europe and Africa, and often require two different hosts for completion of their lifecycle. Several species of tapeworm can infest humans, notably Taenia solium, the pork tapeworm, and T saginata, the beef tapeworm.
Of the three stages (egg, larva and adult), the first two are usually ingested. The adult is a hermaphrodite, so only one worm is needed in each host in order for the worm to reproduce.
The tapeworm anchors its head to the host's large intestine by means of suckers and hooks. It derives its nutrition from the food ingested by the host, so can cause weight loss. It is a common cause of malnutrition in Africa and South-East Asia.
A single adult can produce thousands of eggs and these are excreted in the bowel motions of infected individuals. The adult worm cannot live without a host.
The infestation is often asymptomatic. Sometimes the host may experience upper abdominal pain, diarrhoea, hunger, tiredness, nausea or loss of appetite. If the infestation is severe, the mass of worms can cause an intestinal obstruction, which requires surgical intervention.
This situation is only seen in circumstances where there is poor access to healthcare. Rarely, the larvae can migrate to the brain and cause seizures. If this is suspected, a CT or MRI scan should be arranged.
Tapeworm infestation is spread through the ingestion of inadequately prepared meat or fish, or living and eating in conditions of poor hygiene, where eggs or larvae from the stools of infected individuals are transferred to food and ingested.
It is essential that travellers eat in restaurants that are clean and where the food is prepared hygienically and is well cooked. It may be advisable to avoid eating meat, particularly beef or pork, in countries where tapeworm infestation is common.
Scrupulous handwashing is also essential to prevent the spread of tapeworm infestation from infected individuals to others.
In the US, there have been cases of people who have deliberately infected themselves with tapeworms in a desperate attempt to lose weight.
As a result, it is illegal to keep tapeworms in the US.
Diagnosis and treatment
The diagnosis is made by looking for segments of the worm in stool, FBC, which may indicate a parasitic infestation, and LFTs, which may be affected if the worm infects the liver. Blood can also be checked for antibodies, which may have been produced during an infestation.
Tapeworm infestation can be treated with praziquantel as a single dose (prescribed on a named-patient basis only) and laxatives.
Hygiene is very important while the patient is receiving treatment. The treatment kills the worm and the dead tapeworm dissolves or is passed out in the bowel motions. Sometimes, the patient experiences cramps when the worm is passed. The treatment is generally very effective and clears the parasite from the system.
As follow-up, further stool samples can be sent at three and six months to ensure no further segments of the worm are being passed and that the tapeworm infestation has been cleared from the system.
- Dr Ramanathan is a GP in London