Neurocysticercosis

Cysticercosis is the infection which occurs due to infestation of human beings by the parasite tape worm, i.e. Taenia solium. When it affects the central nervous system, it is called “neurocysticercosis”. Neurocysticercosis remains a major cause for convulsions, unconsciousness, coma and various neurological problems in underdeveloped countries. But it also exists in developed countries. In fact it is a health issue for concern in the USA, due to entry of immigrants carrying the infection with them. The infection is acquired through consuming food contaminated with infected faeces of carriers of Taenia infection. Eggs are shed in the faeces of a person suffering from tape worm infestation. They are then ingested via mouth of another person due to consumption of food or water contaminated with the faeces containing these eggs. Once these eggs reach the stomach of a person, they are exposed to acid and lose their protective covering. Here they turn into larval cysts called onchosphere. Onchospheres migrate to other parts of the body via the blood stream and also reach the central nervous system including the brain and its coverings, spinal cord, eyes and muscles. Pigs are the intermediary hosts for Taenia solium. The pig can get infected by eating contaminated feces. Now when somebody consumes uncooked or partially cooked pork of the infected pig, he can acquire the infection. These cysts can remain in the brain for many years with the person remaining without any problem. Development of disease depends on the number of cysts present and immunity of the person. If there is a large number of cysts compressing brain substance or the immunity of the person is reduced due to any reason, he or she may develop symptoms. The various clinical manifestations depend on the affected part of the brain. Numbers of cysts influence the severity of symptoms. Convulsions are the most common clinical manifestation. They occur due to pressure of the cysts on the brain substance. There can be associated severe headache, visual disturbances, sudden blindness and loss of consciousness in varying degree. Neurocysticercosis should be considered if somebody, particularly a young adult develops convulsions suddenly, with no preceding fever or trauma. Diagnosis is confirmed by computerized tomography and other imaging techniques of the brain like MRI (magnetic resonance imaging), which show the typical cysts. Stool examination can at times show the eggs which have been shed in the faeces. Treatment is by antihelminthic drugs which have to be taken for a long time to ensure total clearance of the cysts. Conditions like neurocysticercosis are better prevented than treated. Because it has the potential to make a healthy person invalid. If the treatment is delayed, there can be irreversible brain damage. Maintaining utmost hygiene during handling, preparation, serving and eating of food is the only preventive measure. Any food item, whether meat or vegetables should be thoroughly washed preferably in hot water before being eaten or cooked. Uncooked or partially cooked meat should never be consumed as the risk of neurocysticercosis is much more with partially cooked meat specially pork. The person serving food should make sure that his or her hands are washed thoroughly with soap and water before touching the dishes. Nails should always be clipped short and kept clean; otherwise, there is risk of germs being harboured below nails. Same thing applies to one who has to eat the food prepared. If his hands are dirty then he is at risk of acquiring all faecal-oral infectious germs including that of neurocysticercosis. Public should be sensitized about this preventable malady and educated about the importance of adopting good hygienic measures. Proper disposal of human waste in developing countries is another measure which would be very useful in long term in bringing down prevalence of diseases like neurocysticercosis. rachna212002@yahoo.co.uk