DIPHYLLOBOTHRIASIS

Prepared byAna M. Vega Ramos

Causal Agents:

The cestode Diphyllobothrium latum  (the fish or broad tapeworm), the largest human tapeworm. 

Several other Diphyllobothrium species have been reported to infect humans, but less frequently; they include  D. pacificum, D. cordatum, D. ursi, D.

dendriticum, D. lanceolatum, D. dalliae, and D. yonagoensis.

Geographic Distribution:

Diphyllobothriasis occurs in the Northern Hemisphere  Europe, Soviet Union , North America, Asia,

Uganda, Peru and Chile. 

Geographic Distribution :

Fish infected with the larva may be transported to and consumed in geographic areas where active transmission does not occur. 

For example, cases of D. latum infection associated with consumption of imported fish have been recently reported in Brazil

Epidemiology:

Causes ingestion of infected, raw, fish.

Reservoir Freshwater fish or saltwater fish

Transmission Ingestion of raw fish or poorly cooked fish

Incubation time 3-6 weeks

Life Cycle

Clinical Features: MC asymptomatic.  Diphyllobothriasis can be a long-lasting

infection (decades).  Manifestations may include

abdominal discomfort, diarrhea, vomiting, and weight loss. 

Vitamin B12 deficiency with pernicious anemia.  Massive infections may result in intestinal

obstruction.  Migration of proglottids can cause cholecystitis

or cholangitis.

Diagnosis

1- Detect eggs and segments in feces2- Anaemia in blood picture

Treatment

1- Praziquantel2- Niclosamide3- Vitamin B12

Prevention and Control

1- Sanitary disposal of feces and sewage2- Proper cooking/ freezing of fish3- Treat infected patients4- De-worm 5- Health education

Proper cooking/ freezing of fish

The FDA recommends Cooking

Cook fish adequately (to an internal temperature of at least 145° F [~63° C]).

Freezing At -4°F (-20°C) or below for 7 days (total

time), or At -31°F (-35°C) or below until solid, and

storing at -31°F (-35°C) or below for 15 hours, or

At -31°F (-35°C) or below until solid and storing at -4°F (-20°C) or below for 24 hours.