Rabies is a uniformly fatal disease having cosmopolitan distribution except Antarctica. Approximately 50,000 cases of human rabies occur across the globe each year. Historically, dogs were the primary reservoir and vector for rabies, and they remain the major source of transmission to humans in Asia and Africa. Worldwide, transmission from dogs accounts for 90% of human cases. In Africa and Asia, other animals serve as prominent reservoirs, such as jackals, mongooses, and raccoon dogs. In industrialized nations canine rabies has been largely controlled through the routine immunization of pets. Well coordinated vaccination and surveillance programs have essentially eliminated the rabies reservoir in dogs in North America and Europe and have uncovered previously unsuspected reservoirs in wildlife species.         
DISEASE TRANSMISSION: Rabies virus is abundantly found in the saliva of infected animals and transmission occurs almost exclusively through inoculation of the infected saliva through a bite or scratch from a rabid mammal. Approximately 35–50% of people bitten rabid animal and receiving no postexposure prophylaxis (vaccine) contract rabies, which is very high if the victim has suffered multiple bites and if the inoculation occurs in highly innervated parts of the body such as the face and the hands. Infection does not occur after exposure of intact skin to infected secretions, but virus may enter the body through intact mucous membranes. Rabies has been transmitted by corneal, lung, liver, and kidney transplantation from tissue harvested from patients dying from unspecified encephalitis or who were misdiagnosed. The duration from bite to onset of symptoms is usually 1–3 months but in rare cases is as short as 2 weeks or >1 year. During most of this incubation period, virus is thought to be present at or close to the site of inoculation, predominantly in muscle cells. Administration of rabies post exposure vaccine during this incubation period is critical; the benefit of post exposure vaccine in preventing disease progression once virus has entered peripheral nerves is limited. Clinically apparent rabies infection begins with nonspecific prodromal symptoms, including fever, malaise, headache, nausea, and vomiting. Anxiety or agitation may also occur. Paresthesias, pain, or pruritus (painful itching) near the site of the exposure occurs in 50–80% of patients and suggests rabies. The wound has usually healed by this point, and these symptoms may reflect infection of local dorsal root or cranial sensory ganglia. Rabies has 2 principal clinical forms. Encephalitic or “furious” begins with nonspecific symptoms, including fever, sore throat, malaise, headache, nausea and vomiting, and weakness. Characteristically patients with rabies encephalitis initially have periods of lucidity intermittent with periods of profound altered sensorium, but ultimately the condition progresses to coma. The cardinal signs of rabies, , are manifested by agitation and fear created by attempting to drink and fanning air in the face, which in turn produces chocking and aspiration through spasms of the larynx, neck, and chest wall. The illness is relentlessly progressive, and death almost always occurs within 2–3 wk after onset.  A 2nd form of known as paralytic or “dumb” rabies is seen much less frequently and is characterized principally by ascending motor weakness affecting both the limbs and the cranial nerves. Most patients with dumb rabies also have some element of encephalopathy.
PREVENTIVE MEASURES: Primary prevention of rabies infection includes avoiding contact with potentially rabid animals and vaccination of all domestic animals. Special efforts should be made to teach children to avoid wild animals, stray animals, and animals with unusual behavior. Stepwise measures after a rabid animal has bitten is to cleanse the wound thoroughly. Soapy water is likely sufficient, and its effectiveness is supported by a broad experience, but other commonly used disinfectants, such as iodine-containing preparations (betadine), are virucidal and should be used in addition to soap when available. Probably the most important aspect of this component is that the wound is cleansed with copious volumes of disinfectant. Antibiotics and tetanus prophylaxis  should be applied using usual wound care criteria. The 2nd step is administration of passive immunization with Rabies Immunoglobulin (RIG). Human RIG is expensive and in short supply, and it is not available in all centers, for which an alternative is Equine RIG serves as a substitute for the human immune globulin preparation in some areas. The 3rd component after the rabid bite is active immunization with vaccine. In both children and adults, vaccines are administered intramuscularly in a 1 mL volume in the deltoid or anterolateral thigh on days 0, 3, 7, 14, and 28 after presentation. However in Feb. 2011, the Advisory Committee on Immunization Practices (ACIP, USA) updated its recommendation for PEP, reducing the regimen to 4 doses over 2 weeks, as opposed to 5 doses over 1 month. Injection into the gluteal area has been associated with a blunted antibody response, and this area should not be used. The rabies vaccines can be safely administered during pregnancy. In most persons the vaccine is well tolerated. Pain and erythema at the injection site occur commonly, and local adenopathy, headache, and myalgias occur in 10–20%. Approximately 5% of persons who receive the human diploid cell vaccine experience an immune complex–mediated allergic reaction, including rash, edema, and arthralgias, several days after a booster dose. In dogs, cats, and ferrets, symptoms of rabies always occur within several days of viral shedding; therefore, in these animals a 10-day observation period is sufficient to eliminate the possibility of rabies. In most instances PEP can be deferred until the results of observation or brain histology are known. In cases where the risk forrabies contact is high, the vaccine series can be initiated and then discontinued if the results from the animal are negative. No duration of time between exposure and onset of symptoms should preclude rabies  prophylaxis. Rabies post exposure prophylaxis is most effective when applied expeditiously and is likely not effective once the virus has entered the peripheral nerve. Nevertheless, the series should be begun in the asymptomatic person as soon as possible regardless of the length of time since the bite.
PRE-EXPOSURE PROPHYLAXIS (VACCINE ADMINISTRATION BEFORE BITE): The killed rabies vaccine can be given to prevent rabies in persons at high risk for exposure to wild-type virus. These include laboratory personnel working with rabies virus, veterinarians, and others likely to be exposed to rabid animals as part of their occupation. Pre-exposure prophylaxis should be considered for persons traveling to a rabies-endemic region where there is a credible risk for a bite or scratch from a rabies-infected animal, particularly if there is likely to be a shortage of RIG or cell-culture based vaccine. The schedule for pre-exposure prophylaxis includes 3 intramuscular injections on days 0, 7, and 21 or 28.
SAFETY TIPS FOR ALL:  It is important to note that any dog can bite, especially if injured or fearful. Since children are most at risk, for many reasons, who may approach dogs without hesitation or engage in rough play or fur-grabbing, resulting in injury. The small size and developing immune systems of children make a bite wound more likely to result in serious injury or infection. Additionally, children usually run while playing or may run away from a dog, inciting a chase and tackle.
AS PER AMERICAN VETERINARY MEDICAL ASSOCIATION (AVMA): Never approaching an unfamiliar dog, especially one who’s tied or confined behind a fence or in a car. Don’t pet a dog—even your own—without letting him see and sniff you first. Never turn your back to a dog and run away. A dog’s natural instinct will be to chase and catch you. Don’t disturb a dog while she’s sleeping, eating, chewing on a toy, or caring for puppies. Be cautious around strange dogs. Always assume that a dog who doesn’t know you may see you as an intruder or a threat. While approached by a dog who may attack you, follow these steps: Resist the impulse to scream and run away. Remain motionless, hands at your sides, and avoid eye contact with the dog. Once the dog loses interest in you, slowly back away until he is out of sight. If the dog does attack, “feed” him your jacket, purse, bicycle, or anything that you can put between yourself and the dog. If you fall or are knocked to the ground, curl into a ball with your hands over your ears and remain motionless. Try not to scream or roll around. There is no way to guarantee that your dog will never bite someone. But you can significantly reduce the risk. While this awareness towards preventing bites in humans, it will be helping to be observant with “bite behavior” of the stray dogs while out on walks.
CONCLUSION: Authorities should take notice of the rising dog population, and mounting fear pressure in particular in parents of school going kids, cost-effectiveness of the anti-rabies vaccine, and its availability to avert further accidents.

(The author is Registrar in Pediatrics SKIMS Medical College, Bemina Srinagar; aashraf_05@yahoo.co.in

Lastupdate on : Tue, 22 Mar 2011 21:30:00 Makkah time
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