Rabies

Rabies is a severe viral infection transmitted to humans by animals. It affects the brain and nervous system. Virus in the animal's saliva is transmitted through a bite or when the rabid animal licks an open cut or wound. On rare occasions the virus can be inhaled, e.g. from exposure to air in caves which are densely populated with rabid bats. In developing countries dogs and monkeys are the most common source of human infections. However bats, skunks, cats and foxes can also transmit it. Rabbits, squirrels, chipmunks, rats and mice are rarely infected, but theoretically any mammal with teeth can spread rabies.
Animal behaviour is NOT a reliable sign as to whether an animal is rabid, as the animal can look healthy while the rabies is slowly growing within its brain. The only only guaranteed way to tell is by killing the animal and examining its brain.

What Countries Are Affected?

Most countries within Asia, Africa and South America have infected regions. Countries with a significant rabies problem include Bangladesh, Bolivia, China, Colombia, Ecuador, El Salvador, Ethiopia, Guatemala, India, Mexico, Nepal, Peru, Philippines, Sri Lanka, Tanzania, Thailand, & Vietnam. There is also rabies In Europe and North America, but many animals there are vaccinated against rabies and the risk is lower. Many countries are rabies free, such as the UK, Japan and New Zealand. Islands in Indonesia are also infected, including Bali.

Worldwide, there are at least 55,000 human deaths each year from rabies. Approximately half of these occur in India.

Signs And Symptoms Of The Disease

The average incubation period (the time between being bitten and when symptoms occur) is 3 -12 weeks, but can be anywhere between 4 days and several years. There are usually no symptoms during the incubation.

EARLY SYMPTOMS

  • Headache
  • Fever
  • Tiredness

· Pain, itching or tingling at the site of the wound

  • Nausea

LATE SYMPTOMS

  • Muscle spasms
  • Inability to drink and swallow
  • Paralysis
  • Convulsion

FINAL STAGE

Coma, cardiac or respiratory failure, and almost always death.

Prevention

The most effective preventative measure is to avoid contact with animals. Children are particularly vulnerable to animal bites, and are more likely to have severe bites. They are also less likely to report that they have been bitten or scratched. Cyclists are also at a higher risk of getting bitten. Other high-risk groups include cave explorers, botanists & naturalists and animal handlers, e.g. zoologists, veterinarians and abattoir workers. Travellers visiting high-risk countries for longer than 30 days should consider vaccination. Anyone going to a remote area or a country where it will be difficult to obtain post-exposure treatment should also consider vaccination.

Pre Exposure Vaccination

There is a choice of route of vaccines;

  • intramuscular - this is a course of 3 vaccines given into the muscle over a period of 3-4 weeks
  • intradermal - this a course of 5 vaccines given just under the skin over 3-4 weeks and a blood test

Both courses should be commenced 6-8 weeks before departure. A blood test can be performed at regular intervals (1-2 yearly) to confirm ongoing immunity. Alternatively, if time is short before high-risk travel, a booster can be given.

This does NOT eliminate the need for post-exposure vaccination, however it does mean;

  • your chances of survival are much higher.
  • you will not need rabies immunoglobulin for treatment (a blood-based product that can be difficult
    to obtain).
  • you only need 2 post exposure injections as opposed to 5.
  • you have more time to get to a doctor or hospital (1 week rather than 2 days).

Post Exposure Treatment

The most important treatment is to clean the wound thoroughly.

  • immediately wash and flush with soap and water. Do this for a long period of time, 20 minutes if possible.
  • apply either 40-70% alcohol or tincture of iodine.

Seek Medical Aid

It is important to receive treatment as soon as possible as the likelihood of success decreases the longer the treatment is delayed. If treatment is given within 48 hours it is likely to be 100% successful.

If you have had pre-exposure vaccinations, we still recommend that you obtain medical care within 7 days. If you have not had pre-exposure vaccinations, seek medical attention as soon as possible, preferably within 48 hours.

  1. If you have not had pre-exposure vaccination, rabies immunoglobulin (RIG) must be injected into and around the wound, and intramuscularly. This is a blood product, which is often not available in developing countries. If blood products are not adequately screened and tested, there is also the risk of transmitting blood-borne diseases such as HIV or hepatitis B or C. You should also consider bringing your own supply of sterile needles and syringes when travelling to developing countries.
  2. The wound must not be stitched.
  3. Start a course of post exposure rabies vaccination. This involves 4 doses of the vaccine - one each on days 0, 3, 7 and 14 (5thdose required on day 28 only if immunocompromised). Stop chloroquine and mefloquine (lariam) as these interfere with absorption of rabies vaccine. (Remember to continue using other methods of protection against malaria such as long sleeved clothing, insect repellents, permethrin and mosquito nets).
  4. Have a tetanus injection if this is not up to date.

The problem of rabies is enormous and most developing countries are unable to do much to prevent it. In parts of India, 1 in 500 hospital admissions are due to rabies from dog bites. 3 in 10 dogs caught in Bangkok carry the rabies virus.

AVOID ALL ANIMAL CONTACT

whilst overseas in areas with rabies and if you are unlucky enough to be exposed,

SEEK MEDICAL ADVICE IMMEDIATELY.
© 2014, Travel Medicine Centre Perth