Microbial Diseases Of The Nervous System |
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Objectives: Viral Diseases of the Nervous System
For each microbial disease listed give the following if applicable:
Diseases:
Additional Objectives:
List the zoonotic (transmitted to humans from animals) diseases studied. |
Polio is caused by a picornavirus and is found only in humans.
It is transmitted by ingestion of fecally contaminated water.
Symptoms:
The virus first invades lymph nodes of the neck and small intestine. Viremia and spinal cord involvement may follow. Death may occur by respiratory failure.
Most cases are mild or asymptomatic. Vaccines keep the incidence low in the US.
Vaccines:
Diagnosis is based on isolation of virus from feces and throat secretions and the presence of virus-neutralizing antibodies in the serum.
Iron Lungs
Reported Cases Of Poliomyelitis In The U.S., 1950-2002
Caused by a rhabdovirus, results in an acute, usually fatal encephalitis.
Rabies is contracted through the bite of rabid animal, by inhalation of aerosols, or invasion through minute skin abrasions. The virus multiples in the skeletal muscle and in connective tissue.
Encephalitis occurs when the virus moves along peripheral nerves to the CNS.
Pathology Of Rabies Infection
Symptoms: Spasms of mouth and throat muscles (hydrophobia) and brain and spinal cord damage and death.
Diagnosis is by direct immunofluorescent (FA) test of saliva, serum or CSF or brain smears.
Reservoirs include skunks, foxes, raccoons.
Animals likely to contract the disease include domestic cattle, dogs and cats.
Rodents and rabbits seldom get rabies.
Bats are the only animal that can harbor the rabies virus without getting the disease.
Treatment: Pasteur - Multiple subcutaneous injections of attenuated virus isolated from rabbit spinal cords. Modern postexposure treatment includes administration of human rabies immune globulin (RIG) and multiple intramuscular injections of human diploid cell vaccine. Treatment, whether pre- or postexposure is aimed at mobilizing immune response before the virus can move from peripheral nerves into the CNS. Once the virus has invaded the CNS the likelihood of survival is pretty much zero. I wouldn't consider the one survivor who didn't receive post exposure treatment a benchmark but rather an anomaly.
Preexposure treatment consists of vaccination with human diploid cell vaccine.
Reported Cases Of Rabies In Animals
Symptoms: Chills, fever, headache and eventual coma.
Several types of arboviruses that are transmitted by Culex mosquitoes cause the disease.
The reservoir is birds. Outbreaks are more common in the summer months when mosquitoes are most numerous.
Notifiable arboviral infections are:
Diagnosis is based on serological tests.
Immune globulin is used to provide passive immunity.
Prevention: eliminate the vector.
Arborviral Infections Of The Central Nervous System
