RabiesPaul R. EarlFacultad de Ciencias BiológicasUniversidad Autónoma de Nuevo LeónSan Nicolás, NL, Mexicopearl@dsi.uanl.mx
Rabiesis a wellknown and dreaded fatal infection caused when the rabies virus invades the central nervous system (CNS). . Rabies virus belongs to the order Mononegavirales, viruses with a nonsegmented, negative-stranded RNA genomes. This bullet-shaped RNA virus belongs to the genus Lyssavirus of the Rhabdoviridae. Rabies involves the CNS, causing acute encephalomyelitis (inflammation of the brain and spinal cord), severe clinical and neurologic signs, and disruption of normal functions.
Pasteur treatment. On an afternoon about 6:30, a rather tough-looking guy came into the lab and sat down without speaking. After awhile, I said, “Well Verne, what happened?” “I cut myself on a tube.” He was working on rabies in cell culture. “Are you going to take the Pasteur treatment?” “No.” Luckily nothing happened.
The idea is that killed rabies vaccine, sometimes as 14 painful shots, will elicit antibodies which will kill the natural infecting virus before that virus can invade nerves. If nervous tissue is invaded, the patient will die. Today the Pasteur treatment is sometimes called: POST-EXPOSURE PROPHYLAXIS !
The roles of Edward Jenner with cowpox prevention of smallpox and Louis Pasteur aided by Emile Roux with killed rabies rabbit brain vaccine are too wellknown to recite here. The Pasteur treatment changed the entire world.
On July 6, 1885, 9-year old Joseph Meister and his mother appeared at Pasteur's laboratory. Two days before the boy had been bitten repeatedly by a rabid dog. He was so badly mauled he could hardly walk. With much trepidation, Pasteur treated the youth. Despite Pasteur's fears, Meister made a perfect recovery. Later another victim who was a young shepherd also bitten by a mad dog. Following his successes, Pasteur received tumultuous acclaim. He became a hero and a legend.
Symptoms. Without the bite as a guide to symptoms, rabies cannot be diagnosed, and even with the bite little indeed can be done. Initial symptoms include: a) restlessness, b) shortterm depression, c) abnormal sensation, such as itching, tingling or numbness radiating from the bite, d) headache, e) fever, f) lethargy, g) nausea, h) sore throat, i) loss of appetite, j) muscle stiffness, k) pupil dilation, l) increased saliva production, and m) unusual sensitivity to sound, light, and temperature.
Epidemiologic distribution, mainly in the US.Important vectors like raccoons and foxes may be hardly noticed, whereas thanks to Hollywood bats and madness are sometimes stressed. Maps are largely thanks to the US Communicable Disease Center (CDC), because they have the best kept data. The actual world database demands renewed efforts, e. g., rabies virus strain per animal host, use of oral vaccine baits for wildlife mammals, etc.
Are bats in California, Texas and New England accounting for most human rabies there? In the US, these are insect-eating bats. Infection by bats is underinvestigated.
Managment of animals that bite humans.a) A healthy dog, cat or ferret that bites a person should be confined and observed daily for 10 days. Do not administer rabies vaccine in the observation period. Such animals should be evaluated by a veterinarian at the first sign of illness during confinement. Any illness in the animal should be reported immediately to the local health department. If signs suggestive of rabies develop, the animal should be euthanatized and the head shipped for testing. Any stray or unwanted dog, cat, or ferret that bites a person may be euthanatized immediately and the head submitted examination.
Current vaccines.These are TRIMUNE, Fort Dodge Animal Health, DEFENSOR 1, Pfizer, Inc., DEFENSOR 3, Pfizer, Inc., RABDOMUN, Pfizer, Inc., RABDOMUN 1, Pfizer, Inc., RABVAC 3, Fort Dodge Animal Health, PRORAB-1, Intervet, Inc., PRORAB-3F, Intervet, Inc., IMRAB 3, Merial, Inc., and IMRAB IMRAB 3 TF Large Animal Merial, Inc., and IMRAB 1, Merial, Inc.
Virus structure. Rhabdoviruses are about 180 nm x 75 nm. The rabies genome encodes 5 proteins: 1/ nucleoprotein (N), 2/ phosphoprotein (P), 3/ matrix protein (M), 4/ glycoprotein (G) and 5/ polymerase (L). All rhabdoviruses are have 2 major structural components: 1/ a helical ribonucleoprotein core (RNP) and 2/ a surrounding envelope. In the RNP, genomic RNA is tightly encased by the nucleoprotein.
Overview of rabies. Many diseases are shared by man, his domestic animals and wildlife, rabies of course being one of this multitude. Actually, the risk of rabies is very low and would rise only by public health neglect. Countries like India still have some human deaths. Wildlife is underinvestigated. Successful reduction of virus prevalence by oral vaccine baits is fully convincing as Europe is now practically free ofrabies.
The Pasteur treatment is practiced more around the globe. The use of highly purified cheap horse immunoglobulins provide a solution to the current problems of insufficient quantities and the high cost of human immunoglobulin.