Rabies
Rabies is a highly fatal viral encephalomyelitis which is transmitted to man by the bite of a rabid animal.
The rabies virus has a strong affinity to the cells of the central nervous system.
The virus is inactivated by sunlight, ultraviolet light, ether, formalin, mercury bichloride and nitric acid and is resistant to phenol, merthiolate, sulfadiazine and common antibacterial agents.
The rabies virus is killed by a temperature of 56 degrees Celsius in one hour and 60 degrees C in five minutes.
The transmission of the infection is through bites, from dog to dog and from dog to man and domestic animals.
Once bitten by a rabid animal, the rabies virus proceeds to the central nervous system. And it is in the period between the viral inoculation and nerve invasion where the prophylactic vaccine treatment is effective.
After the virus infects the Central nervous system, it will spread through the peripheral nerves to the salivary glands and also to the lungs, adrenals, kidneys, bladder and testicles.
Clinically, the rabies infection will have an incubation period in man: from 4 to 8 weeks but can be also from ten days to 1 year. It tends to be of shorter incubation if the bites are severe and more on the head or neck.
The manifestations are divided into three phases:
A. Prodromal Phase
– fever
– body malaise
– sore throat
– salivation
– lacrimation
– perspiration
– irritability
– restlessness
– drowsiness and
– depression
– numbness , tingling, burning or cold sensation in the area of the bite
B. Second Phase
– marked excitation
– apprehension
– and even terror may occur
– delirium
– maniacal behavior may alternate with listlessness and depression
– in this second stage, the characteristic feature of rabies becomes manifest that is the violent and painful spasm of the muscles of the mouth, pharynx and larynx on attempting to swallow food or water and even at the mere sight of them
– Death may occur during an episode of spasm
C. Terminal Phase
– this may occur in 1-3 days where the patient deteriorates rapidly
– there is tachycardia, labored irregular respiration and rising temperature
– spasms may cease and increasing paralysis sets in that may lead to coma and death due to respiratory paralysis
Rabies is a highly fatal disease thus important aspects its control must be addressed:
1. Control and eradication program for urban rabies
2. Control measures for wildlife rabies
3. Internal regulations regarding transfer of animals and
4. Pre and post exposure vaccination schedules for man
5. Immunization of domestic dogs and cats
6. Elimination of street dogs
Source:
Textbook of Pediatrics and Child Health
By: Dr Fe Del Mundo, Dr Felix Estrada, Dr Perla Santos Ocampo