Salad Scare

How Can I Get Neurocysticercosis?

Tapeworm larvae travel from pigs, which are hosts, to humans through the oral-faecal route, says neurosurgeon Amitabh Verma, of Delhi’s Advanced Neurological Care Centre. ‘‘Tapeworm larvae or eggs are found in excreta, which is commonly used as manure. While pork from an infected pig can cause the infection, eating contaminated vegetables is the other route through which neurocysticercosis can occur,’’ explains the doctor who has presented several papers on the disease. Nearly 30 per cent of the patients at Verma’s clinic are diagnosed with NCC.

Tapeworm eggs can cling on to the surface of leafy or ridged vegetables in spite of rigorous washing. Once the eggs are lodged in human intestines, they may develop into larvae (cysticerci) which lodge in soft tissues, especially skin, muscle and brain.

What Are The Symptoms?

In humans, tapeworm larvae survive in the form of fluid-filled cysts, measuring between 1mm to 2cm in diameter. Live cysts can go undetected for several years, because the body’s immune system does not fight them unless they are present in huge numbers.

When the larvae inside the cyst dies or begins to degenerate, the central nervous system generates an inflammatory response, which manifests in several forms. The most common symptoms of NCC is epilepsy — in fact, one-third of adult-onset epilepsy cases in the world are due to NCC, according to the Atlanta-based Centers for Disease Control and Prevention (CDC).

‘‘It also causes a condition called pseudo tumour cerebri because it mimics a brain tumour,’’ says Verma. Other symptoms include increased intracranial pressure leading to severe headaches, sensory disturbances, motor and speech impairment and sometimes, dementia, adds Verma. If untreated, NCC can lead to loss of vision because increased pressure in the brain can damage the optic nerve.

How Is Neurocysticercosis Treated?

The treatment for NCC depends on the number, size and location of cysticerci. Once a neurosurgeon diagnoses NCC, with the help of imaging technologies such as the MRI and CT scans, treatment may be symptomatic or curative. Anticonvulsants are given to treat seizures. Common drugs used to treat NCC include albendazole and praziquantel, which are

administered as one-week, two-week or four-week courses.

Surgery is not a common option, though it may be performed if the doctor deems it necessary.

How Can I Safeguard Against It?

You could stay away from raw vegetables and pork products, but since that may not always be possible, here are a few tips:

• Scrub all vegetables very carefully with detergent and lots of running water
• Wherever possible, peel vegetables before chopping them for salads
• If you grow vegetables at home, make sure you buy fertiliser from a known source
• Stay away from fresh pork. If you’re buying processed pork products, make sure it’s from a reputed manufacturer, and always cook before eating
• Don’t buy vegetables from the roadside. Very often, they are grown on sewage-laced land and washed in dirty water.