Taeniasis is a zoonotic disease caused by specific cestodes. The two parasites of major importance are Taenia saginata and T. solium. Both in their adult forms, are obligatory parasites of man and there is no non-human primates, carnivores, or other mammal which serves as their final hosts in the natural transmission cycle.
The larval stage of T. saginata mainly occurs in cattle and called Cysticercus bovis.It was also reported from reindeer. The cysticerci are commonly found in the heart and the muscles of mastication.Pig is the main host for the larval stages of T. solium (Cysticercus cellulosae). Man may also be infected due to poor personal and environmental hygiene. The pork containing the Cysticercus cellulosae is known as measly pork.
Epidemiology: Man is the definitive host. The mode of transmission for T. saginata is by ingestion of raw or inadequately cooked beef containing the infective larvae ( C. bovis). Transmission of T. solium results from the ingestion of raw or inadequately cooked pork containing the infective larvae (C. cellulosae) or by direct transfer of eggs in faeces of a person harbouring an adult worm to his own or another’s mouth, or indirectly through ingestion of food, vegetables and water contaminated with such eggs.T. saginata is not directly transmitted from man to man but T. solium may be. The adult stage of T. saginata and T. solium may persist for several years in infected human. Usually only one parasite is present but multiple infection can occur as mixed infection with T. saginata and T. solium.
Clinical features: Incubation period is about 8 to 14 weeks. Clinical manifestation of infection is usually asymptomatic but may lead to nervousness, insomnia, anorexia, loss of weight, abdominal pain and digestive disturbances, the mobile gravid segments may make their way to unusual sites such as the appendix, biliary tract and may cause serious disorders.Cysticerosis, the larval infections of T. solium, is a serious somatic disease that may involve many different organs and tissues. Subcutaneous tissues, striated muscle, other tissues and vital organs of the body are commonly involved. Consequences may be grave when larvae localize in the ear, eye, central nervous system or heart. Cysticercosis is a chronic disease. It may cause serious disability with relatively high mortality rate.
Laboratory diagnosis: T. saginata infection can be recognized by observing detached gravid segments in the faeces. However, diagnosis cannot be used on a single faecal examination. Infection by T. solium is diagnosed usually by examining the faecal specimens. With barium, the cestodes in the intestine can sometimes be demonstrated radiologically.
The serological techniques such as indirect immunofluorescent test, passive haemagglutination test, ELISA test and precipitation test can also be used for supporting diagnosis.
Control and prevention: Following methods are used to control and prevent the spread of disease.
1. Education of the public to prevent soil and water contamination with human faeces.
2. Personal hygiene and health education including washing of hands after defecating and before eating.
3. Swine should not be permitted access to latrine or to human faeces.
4. Inspection of slaughtered animals and condemnation or treatment of carcasses.
5. Keeping the animals indoor which leads to the restriction of contact between animals and human faeces.
6. Development of reliable and cheap methods for antemortem and postmortem diagnosis of cysticercus stage in pigs and cattle.
7. Treatment of persons harbouring the infection.
8. Collaboration of all liaisons between public health and veterinary services.