Zika virus

http://www.telegraphindia.com/1160314/jsp/knowhow/story_74296.jsp

A strange disease

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Your Health - Dr. Gita Mathai

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The Aedes Egypti mosquito has long been spreading diseases such as chikungunya and dengue in India. It has now added another illness to its spectrum -- the Zika virus.

The Zika virus infection in itself is a mild disease. The bite of the infected mosquito is followed by a 3-7 day asymptomatic incubation period. After this, there is mild fever, red eyes, rash and joint pains. Most people recover spontaneously in a few weeks.

The problem with the infection is that, unlike dengue and chikungunya, the Zika virus can cause the Guillain-Barré syndrome. This is a rapidly occurring paralysis that can actually follow any viral infection, not necessarily Zika alone. It can also be precipitated by respiratory or gastrointestinal infections and even vaccination or surgery. The syndrome starts with a tingling and numbness in both feet and then spreads upwards. There may be pain and weakness. A person who was fine is suddenly bed ridden and paralysed within two weeks. Respiratory muscles can be affected making it difficult to breathe. Control of the bowel and bladder is lost. The heart rate may become irregular and the blood pressure may drop. The breathing problems and the heart irregularities can make the disease fatal.

It occurs because as the body tries to fight the virus causing the infection, it makes a mistake and attacks the protective myelin covering of the nerves instead. The nerves are damaged. They are no longer able to transmit signals to the brain or receive reciprocal messages. The tingling sensation signals the initial attack. This is soon followed by paralysis.

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Doctors in the emergency departments are suddenly confronted with a paralysed person who the relatives claim was previously healthy. The precipitating illness (even Zika) may have been so mild as to pass unnoticed. This means that a number of diagnoses have to be considered. It may be due to a stroke affecting both sides (very rare), a injury to the spinal cord, metabolic conditions, heavy metal poisoning, alcohol intoxication, drug overdose or vitamin deficiencies, especially B12 and folic acid.

The diagnosis is difficult. It is arrived at after blood tests, spinal fluid analysis, electromyography, nerve conduction studies and scans. It is a diagnosis of exclusion, when none of the tests yield a positive result

Guillain-Barré tends to worsen for two weeks then plateau for about a month. After that, there is slow recovery, which may take as long as three years. Eighty per cent of those affected (particularly children) recover completely. Some residual symptoms of weakness and pain may remain in the rest of the patients. About five per cent may suffer a relapse or recurrence.

The treatment is mainly supportive, with physiotherapy and strengthening exercises, mobility, pain relief and prevention of blood clots. Recovery can be speeded up with procedures like plasmapheresis and immunoglobulin therapy.

Mosquitoes spread many diseases such as the Zika virus, dengue, chikungunya, malaria, filaria and brain fever. To prevent that we need to:

• Stop stagnant water from accumulating and clear garbage to prevent mosquitoes breeding.

• Sleep in mosquito nets

• Mosquito-proof homes with nylon or metal mesh.

• Use electric "mosquito bats" to rid the house of any mosquitoes that may have entered.

Dr Gita Mathai is a paediatrician with a family practice at Vellore. Questions on health issues may be emailed to her atyourhealthgm@yahoo.co.in