What to do when a dog bites you

CLINICAL MATTERS

A few months ago, a teenager tragically died from rabies after she did not tell her mother that she had been bitten by a stray dog. By the time she asked for help, she had developed symptoms of rabies and it was too late to save her. Shortly afterwards, she died.

The Philippines is one of the countries where dog-mediated rabies continues to kill people every year. Rabies is an often-fatal brain infection caused by a virus that is usually acquired from an animal bite. Not all animal bites can cause rabies in humans. Rodent (mouse, rat, hamster, gerbil, guinea pig), rabbit, and reptile bites do not result in human rabies. Dog bites, cat bites, bat bites, and raccoon bites are among the most frequent causes of rabies in humans. In the Philippines, dog bites are by far the most common vector for rabies infection.

Rabies is preventable. Rabies can be cured, if symptoms have not yet developed. Symptoms of rabies include fear of water (hydrophobia), aggressive and inappropriate behavior, restlessness, excessive salivation, seizures, and disorientation among others. Once these symptoms develop, rabies is almost always fatal, with only one documented case of survival. A rabies vaccine for animals and humans is highly effective for preventing rabies. The same vaccine is also used in animal bites as post-exposure prophylaxis. This is one of the rare cases in which vaccines can be used after exposure to the virus. However, it entails multiple injections over weeks following the bite.

Rabies is not the only complication that can arise from animal bites. Dogs and cats harbor bacteria called Pasteurella multocida, which can cause severe infections and sepsis if the wound is not properly cleaned and treated with antibiotics. Tetanus can also occur if an anti-tetanus vaccine is not given. Last year, I had a patient who was bitten by a cat and got an anti-rabies vaccine but not the tetanus vaccine. The patient ended up spending more than a month in the hospital on a ventilator because of tetanus.

So, what should you do if you are bitten by a dog?

1.If the bite resulted in a large wound, put pressure on the wound to control the bleeding and proceed to the nearest emergency room. If it is a small wound, clean it with soap and water and proceed to the nearest animal bite center for proper treatment.

2. At the emergency room, the doctor will assess the risk of rabies. The risk of the person contracting rabies depends on whether the biting animal is likely rabid and the severity of the exposure. This includes investigating whether the bite was provoked or unprovoked; whether the animal is young (dogs less than one year old are less likely to have rabies); whether the animal has been previously vaccinated for rabies; how deep the wound is and whether the bite drew blood; which area of the body the bite occurred (e.g. head and neck exposures are more dangerous); whether the patient has previously been vaccinated for rabies; and whether there have been reports of rabid animals in the neighborhood.

3.Based on the assessment, the doctor will determine the category of exposure and make recommendations on whether anti-rabies treatment is necessary. The wound will be thoroughly cleaned and dressed.

4. Aside from anti-rabies treatment, an anti-tetanus prophylaxis will be given along with oral antibiotics if warranted. Most animal bites are not sutured unless there is a lot of damage that needs to be repaired, because early suturing can drive the virus deeper into body tissues and increase the risk of infection.

5. Anti-rabies treatment involves a series of vaccinations and injections. The first dose of vaccine will be given immediately at the time of exposure, along with rabies immunoglobulin if appropriate. Rabies immunoglobulin (RIG) is an injection that contains antibodies against rabies. These antibodies are either derived from horse (equine rabies immunoglobulin or ERIG) or human donors (human rabies immunoglobulin or HRIG). HRIG is less likely to cause an allergic reaction but is more expensive and may not always be available. The immunoglobulin injection is infiltrated directly into the area around the wound as appropriate. The total dose of HRIG or ERIG is calculated depending on body weight of the patient.

6. Anti-rabies vaccines can be given through a muscle (intramuscular) or inside the skin (intradermal). The site and number of doses will vary depending on the route of administration, previous rabies vaccination, and the age of the patient. The most common full anti-rabies vaccine post-exposure regimen involves giving intradermal doses at two different anatomic sites (typically left and right arms) on day zero (date of exposure), day seven, and day 14 with an additional two doses on day 28. The day 28 doses are sometimes optional when using WHO pre-qualified vaccines. The number of sites and doses can vary depending on previous pre-exposure prophylaxis, category of exposure, and route of administration. The doctor will make this determination. It is very important that the full regimen be completed in a timely fashion to get the maximum protection possible.

7. If the animal that bit you is a stray, contact the barangay to try to safely capture the animal. Do not attempt to capture the animal yourself since more people may end up being bitten.

8.If the biting animal is a pet and does not show signs of rabies, it can be observed for 14 days and does not need to be killed. It should be kept in an enclosure which will prevent it from biting people during the observation period. All pets should be vaccinated against rabies.

Dog bites in our country can be deadly and these should not be ignored. Seek medical attention immediately if you or your loved ones are exposed. Make sure all your pets are fully vaccinated. The life you save may be your own.