rabies

Animal bites

Your Health
DR GITA MATHAI

Dogs are man’s best friends. They may be street dogs, available for free, or expensive pedigreed animals. People from all walks of life have them at home. But dogs are also responsible for 90 per cent of rabies cases. India has around 30,000 reported deaths from this disease every year. The exact number, however, could be much higher as many cases are not diagnosed or reported.

Rabies is caused by a virus. Once it enters the body through a bite or lick from an infected animal, it travels silently along the nerves till it reaches the brain. This means that after an asymptomatic period — which can range from two weeks to two years — the person begins to experience symptoms. Initially, these are non-specific and may be mistaken for flu. There may be fever, headache and body pain. Later, there may be slight or partial paralysis with weakness of the limbs, anxiety, insomnia, confusion, agitation, terror and hallucinations. The throat muscles eventually become paralysed, making both speech and swallowing painful and later impossible. The person panics when presented with liquids to drink and cannot quench his or her thirst as the muscles go into painful spasms. Death usually occurs within two to 10 days.

It is difficult to suspect or diagnose rabies unless the person mentions the animal bite and also exhibits the classical symptoms of rabies. There is a fluorescent antibody test to demonstrate the presence of a viral antigen to confirm the diagnosis but it is available in very few centres.

Other animals like cats, monkeys, bats, rodents as well as horses and cattle too can transmit rabies. Unaware of this, in case of a bite by any of these animals, many people just apply an antiseptic solution and do not take it seriously. Human to human transmission of rabies does not occur unless a corneal or some other organ transplant has occurred from an infected donor.

House pets — dogs or cats — need to be immunised. Vaccines are available in government veterinary hospitals and private clinics. Booster injections have to be given every year as long as the animal lives. This is often not done, particularly as the animal gets older.

Children often play with stray animals. They are prone to attack but such bites are less likely to be reported. Even if it is a pet animal, a bite or scratch should be taken seriously. The pet’s immunisation may be incomplete or they may be asymptomatic carriers of the rabies virus. Also, there is a silent reservoir of infection from wild animals, which may have attacked the pet and run away unnoticed.

If scratched or bitten, the bruise must first be cleaned thoroughly with soap and water. Soap kills the viruses in the wound. Iodine — either tincture iodine or povidone (Betadine) — should then be applied. The wound should be left open. Suturing should be avoided as a closed environment allows further multiplication of the viruses.

A bite is graded according to its severity. A course of injections (immunoglobins and anti-rabies vaccine) should be started immediately. Prior to the advent of the human diploid cell and other newer vaccines, anti-rabies was injected in the abdomen around the navel. This regimen had many side effects, of which pain was the least sinister and most tolerable! In addition, bites require tetanus prophylaxis and antibiotic cover against aerobic and anaerobic bacteria, which may have infected the wound from the teeth.

A number of pharmaceutical companies market the newer vaccines. The dosage schedule is printed on the package insert and should be meticulously followed. Post-exposure prophylaxis is usually given on days 0, 3, 5, 7, 14 and 28. The injections should be administered intramuscularly in the shoulder and not the buttocks. That’s because the high fat content of the buttocks interferes with antibody production.

Pre-exposure prophylaxis (before the bite) consists of three injections on days 0, 7 and 28 with a booster every five years. It must be taken by all owners of pet dogs or cats, veterinary surgeons, laboratory workers and travellers, especially if they are going to pass through endemic areas where appropriate treatment for animal bites may not be readily available. If your children have a penchant for playing with animals, it makes sense to immunise them too.

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