Bertielliasis is a parasitic infection caused by a type of tapeworm in the Bertiella genus. These worms infect mammals that live in all continents save Antarctica. Bertielliasis occurs when a host animal, which might be a human, eats another host animal that contains the eggs of the tapeworm. This host animal is usually an oribatid mite found in contaminated soil, but fleas have also been discovered. Some cases occur because the person has eaten fruit that's fallen on the ground but hasn't been properly washed off. Most bertielliasis patients are children.
Definition & Facts
The condition is rare in humans and usually occurs in areas where they live closely with other primates or come into contact with them in zoos or as pets. Opossums, koalas and other marsupials can also contract bertielliasis.
The species of tapeworm that parasitizes humans are Bertiella studeri and Bertiella mucronata. B. studeri is found in Asia and Africa, while B. mucronata is found in the Americas. Most cases of bertielliasis are caused by B. studeri, which infects chimpanzees, guenons and macaques. B. mucronata is found in titi and howler monkeys. Both tapeworms belong to the Bertiella genus and the Anoplocephalidae family.
Epidemiologists believe that some of the few cases of bertielliasis found in America were caused by infected monkeys that had been smuggled into the countries where the patients lived. Cases of bertielliasis have been found in the United States and the Caribbean, including Cuba and St. Kitts. South American countries where the infection has been found include Brazil and Argentina. Other countries with cases of bertielliasis are Malaysia, India, Singapore, Australia and Lithuania.
The incubation period of the disease, which is the time it takes between exposure to the infection and the time at which symptoms appear, is unknown.
Symptoms & Complaints
The Bertiella tapeworm is a worm with suckers and a long body with segments that are released into the body of the patient. The segments are called proglottids, and they make up a long, tape-like body called the strobila. Though the tapeworms are usually about 11 millimeters long, one was found that was 130 millimeters long. That's about 5.13 inches long.
Because the condition is so rare, not much is known about the tapeworm's life cycle. Biologists believe the Bertiella tapeworm needs two hosts. The first host would be the mite or flea and the second, definitive host is the human being.
Once in the body, the tapeworm larvae finds the lower gastrointestinal tract and attaches itself to the patient's intestines. The worm is able to live like this for years. During that time, it releases both eggs and bodily segments, which are able to reproduce independently of the worm. The eggs and segments are passed via the host's feces and ingested by mites in the soil. The mites are then eaten by another animal, and the cycle begins again.
Diagnosis & Tests
One way to diagnose bertielliasis is through finding the white segments or eggs in a stool sample of an infected person. Symptoms displayed by the patient also help in the diagnosis of the disease. Bertielliasis can also be suspected if the patient has these symptoms and lives in an area where they come into contact with contaminated soil or non-human primates. However, the eggs and body segments need to be studied for a definitive diagnosis, as bertielliasis resembles many other diseases caused by parasitic worms.
Treatment & Therapy
Bertielliasis is usually treated with medications that are used to fight infections by other parasitic worms. These drugs are called anthelmintics. Praziquantel is a drug that is commonly used to treat parasitic worm infestations. In at least one case, a doctor prescribed the drug in a dose of 40 milligrams for every kilogram of the patient's weight. The patient took a single dose of praziquantel and took another dose 20 days later. Their symptoms subsided.
A more common way to take praziquantel is in recommended doses at least four but no more than six hours apart. If the patient doesn't adhere to this schedule, they need to call their doctor and have another schedule drawn up. The drug is taken in tablet or powder form, and it is recommended that it be taken during meals and washed down with a glass of water.
Patients who are taking praziquantel should not drive or operate heavy machinery. Elderly patients may be especially sensitive to the drug, and it should be prescribed for children only with great care. Doctors also need to be careful when prescribing the drug for women who are pregnant or nursing.
Niclosamide is another drug doctors prescribe to treat bertielliasis. It is used specifically to treat tapeworms. The drug does not work again pinworm infections (enterobiasis) or roundworm infections (ascariasis). Niclosamide is considered an essential drug by the Centers for Disease Control and Prevention even though it has side effects such as itching, diarrhea, stomach pain, and vomiting.
Like praziquantel, it is prescribed according to the patient's age or weight and comes as a chewable tablet. Niclosamide can be taken on an empty stomach with a few sips of water, but doctors recommend that it be taken with meals to reduce the discomfort of abdominal side effects.
Oxyclozanide and dichlorophen are also used to treat bertielliasis, but these medications are largely considered veterinary drugs. Albendazole, a drug that is used for treating other parasitic worm infections, does not work well against bertielliasis.
Prevention & Prophylaxis