Fish Tapeworm

Fish tapeworm

     Botriocephalosis is a parasitosis caused by infestation of the human body with fish tapeworm (Diphyllobothrium latum). Intermediate hosts are at least two: a crustacean and a freshwater fish.

     The fish tapeworm is one of the biggest worms of cestodes class. Cestodes parasites are worms located in the gastrointestinal tract of vertebrates. The fish tapeworm has a head (scolex), throat and reproductive organs equipped with individual segments. Scolex is the part with which the fish tapeworm attaches itself to the intestinal mucosa from which will grow the whole parasite. As they are fertilized (filled with eggs) proglottids increase their size and finally detach their self, being eliminated with faeces.

     The fish tapeworm's life cycle is complex and requires the existence of an infected host that eliminates pregnant proglottids with eggs in freshwater that contains crustaceans and fish, which are intermediate hosts. Freshwater flea ingests embryos. In the flea's body the larvae grows. The flea is then eaten by a fresh water fish. In its body the fish tapeworm's larvae goes into stage two and acquires infective properties for the final host.

     The fish tapeworm reaches maturity in the small intestine of the definitive hosts and in five weeks is able to produce eggs. Fish tapeworms infect a host as long as 10 years. Adult worms can grow enormously, and reaching up to15 feet. It can produce up to 4,000 proglottids and depending on the reproductive activity, one gram of faeces can contain up to 200000 eggs.

     People become infected by eating insufficiently cooked fish meat (which is infected with larvae).

     The disease is reported in countries from Eastern Europe, South America and North African countries and some Asian countries. Individual culinary preferences and poor hygiene are responsible for the high incidence of the disease in these countries.

     Botriocephalosis' is not a disease with an invasive character. Patients are often asymptomatic or accuse symptoms that suggest anemia or vitamin B12 deficiency.

Signs and symptoms

     Most patients are asymptomatic. When symptoms exist, they are nonspecific:

• Abdominal pain or generalized abdominal discomfort, nausea, vomiting, dyspeptic phenomena, diarrhea, loss of appetite or contrary, but its growth with a steady weight loss
• Marked tiredness and fatigue
• Anal itching
• Limb numbness
• If the parasite is very long to reach the intestinal occlusions in its specific manifestations.

Investigations

     Some patients feel when they eliminate worm segments. Observing them under a microscope (between the blade and slide) establishes the diagnosis.

     Basic investigations include:

• blood count: megaloblastic macrocytic anemia shows a (vitamin B12 deficiency - an unusual parasite that has an affinity towards this vitamin), thrombocytopenia; signs of intense haemolysis also appear
• Determination of erythrocyte sedimentation rate (ESR) is increased
• Determine the level of vitamin B12 and folic acid
• Examination of urine - certify hemolysis (increased amounts of urobilinogen appear)

     On physical examination changes in the mouth mucosa are determined (with hypertrophy taste buds, with areas of bleeding on the surface). The patient is pale, tachycardia, dyspnea, asthenia and numbness and can produce disturbances of motor coordination.

     Differential diagnosis is done with other causes of pernicious anemia, hypothyroidism and deficiency of folic acid.

Treatment

     The goal of treatment is eradication of the fish tapeworm infection; the decrease of associated morbidity and prevention of complications. One dose of anti parasitic is administered and vitamin B12 supplements are given to treat anemia.

     The first choice is Niclosamidul. The compound inhibits glucose uptake by the parasite and thus interrupting the power supply. A single, 2 grams dose is administered orally. The most common adverse reactions appear to be: anorexia, abdominal discomfort, rash and headache.

     If the patient can't manage niclosamid, he is given praziquantel (5-10 mg / kg). This drug leads to the paralysis of the worm by modifying the intracellular calcium concentration. Tablets should be swallowed with food. Reported side effects are headache, anorexia, confusion, dizziness. Because of these, the patient should not drive any type of vehicle or handle any equipment on the day of treatment as in one that followers.