By: dr. Maria Dewi
Rabies is a zoonotic disease, a disease of animals that can infect humans. It is a serious and fatal disease. Until recently, there is no proven effective treatment, despite the medical advances. However, there are proven effective preventions.
Rabid Animals
Almost any wild or domestic animal can potentially get rabies. The reported animals are: dogs, cats, bats, monkeys. Rats, squirrels, chipmunks, or rabbits rarely carry the rabies virus. Fish, reptiles, and birds are not known to carry the rabies virus.
The word rabies is taken from Latin, which means mad, rage, fury. The phrase “mad dog” is widely known as the classic sign of a rabid animal, where the infected animal acts vicious, hostile and furious. Actually, a rabid animal can act completely normal. One important point to suspect a rabid animal is when it behaves strangely, i.e. a normally nocturnal wild animal awakes during the day (for example, a bat or a fox) or a normally shy wild animal appears strange or even friendly.
Transmission
The most common transmission is contact from the rabid animal’s saliva. The transmission of the virus is by getting through a bite wound, open cuts of the skin, or onto mucous membranes (i.e. into the eyes or mouth).
Human Symptoms
The average incubation, the time period when the symptoms show, is 20 – 90 days. In more than 90% of cases, the incubation is less than 1 year. The time of incubation also depends on the area of exposure. The nearer it is to the brain, the shorter the incubation time will be. Many times, the patient does not recall the exposure because of the prolonged incubation period.
Without prevention vaccination (prophylaxis) the virus will eventually enter the brain. The early symptoms are non-specific. In 50% of cases, the only sign is numbness and pain on the bitten area. Other symptoms may include feeling tired, no appetite, headache, chills, sore throat, nausea, vomiting, diarrhoea, anxiety, agitation, insomnia and depression.
Within the next 2-7 days, the signs and symptoms of brain infection are more obvious. The classic rabies symptoms or also known as the furious form will show. Patients develop agitation, hyperactivity, restlessness, thrashing, biting, confusion, or hallucinations. After several hours to days, this becomes episodic and interspersed with calm, cooperative and lucid periods. Furious episodes last less than 5 minutes. Episodes may be triggered by visual, auditory, or tactile stimuli or may be spontaneous. Seizures may occur. This phase may end in cardio-respiratory arrest or may progress to paralysis. About 20% of cases will develop the paralytic form. In this form, the patient will have severe muscle weakness. The patient will always complain of having fever and headache. The end stage of the rabies infection is coma. The heart and lungs will fail to work and death occurs shortly after coma. Recovery is unlikely, despite intensive care support. The total regress from the first symptoms to coma usually takes 10 – 14 days.
Preventions
There are 2 ways to prevent rabies:
- 1. Pre-exposure rabies vaccination
This is a vaccination before getting bitten by a rabid animal. It’s recommended for people with risks of exposure, i.e. people handling wild animals, adventurers with high risks of contact with wild animals. The vaccine is given 3 times.
If eventually the person is bitten by a possible rabid animal, he or she will need to have 2 booster injections.
- 2. Post-exposure rabies vaccination
It is given after someone is bitten by a possible rabid animal.
The decision to get post-exposure rabies vaccination
- If you are bitten by a dog, cat, or ferret and the animal does not appear ill at the time, then the animal should be observed by a veterinarian for 10 days. If the animal remains well during that period, you will not need rabies shots. If the animal becomes sick or dies in 10 days, you should start the rabies vaccination.
- If the animal has the potential for rabies and is available for sacrifice and immediate examination by the local health department or veterinarian, then treatment may be withheld depending on the results of that test.
- If the animal has the potential for rabies and is unavailable for sacrifice and examination, then you will be given rabies shots in the emergency department.
The post-exposure prophylaxis consists of 2 types of shots:
- A one-time injection of human rabies immune globulin (or HRIG), which is a substance that provides rapid, short-term protection against rabies. This will give protection while your body is still producing antibody from the rabies vaccination. It is usually injected around the wound.
- A serial injection of rabies vaccine, which is given 5 times.
Other Concerns
The wound. All bite wounds need proper wound care. This includes cleaning the wound with soap and antiseptic. Deep or large bites need debridement by professional medical staff.
Tetanus. If your last tetanus vaccination was more than 5 years ago, your doctor might also recommend a tetanus booster.
