Incubation Period: Generally 20 days to 2 months. However, the period can be as short as a few days or as long or longer than 6 years. The incubation period appears to be determined by several factors:
- Site of the bite wound
- Proximity to the CNS
- Severity of the bite
- Type of virus
- Quantity of virus injected into the site
- Age of the patient
- Immune status of the host
Symptoms Patients usually present with serious neurologic symptoms within 2 to 10 days after onset of the initial symptoms. Rabies manifests in two forms: is characterized by agitation, thrashing, biting, viciousness, choking, gagging, hyperventilation, cardiac arrhythmias, paralysis and death. Paralytic or dumb rabies is characterized more by paralytic symptoms, which may include apathy, apparent depression, increased blood pressure, tachycardia, confusion, hallucinations, and disorientation. These symptoms are followed by increased periods of hyperactivity, stiffness in the back of the neck, and an increase in the number of cells in the cerebrospinal fluid. Dumb or paralytic rabies ends with coma and death by respiratory failure. Rabies develops with three main phases: The onset of symptoms follows these general stages: Prodromal StageProdromal or premontive symptoms are mild and nonspecific. - a slight fever (100 F to 102 F),
- general feeling of uneasiness,
- pain at the site of infection,
- chills,
- cough,
- sore throat,
- Tingling at the bite site.
Acute neurological or excitation phaseThis stage usually lasts 2 to 7 days. - nervousness,
- anxiety,
- insomnia,
- depression, and apathy;
- pain at the site of infection,
- fever / chills,
- cough,
- sore throat and/or hoarseness
- headache and sensitivity to loud noises,
- irritability,
- urinary retention,
- weakness of facial muscles,
- temperature of 103 F,
- secretion of tears,
- excessive perspiration,
- nausea and vomiting.
In the advanced stage of the infection, as it spreads to other parts of the nervous system, the following extremely serious life-threatening symptoms:
- double vision,
- problems moving facial muscles,
- difficulty breathing caused by abnormal movements of the diaphragm and muscles that control breathing,
- difficulty swallowing and increased production of saliva, causing the "foaming at the mouth" usually associated with a rabies infection.
- Episodic mania,
- Episodic calm,
- Restlessness,
- Feverishness,
- Convulsions,
- Painful throat spasms,
- Difficulty swallowing,
- Hydrophobia (fear of water) - an irrational reaction or spasm on seeing or drinking water,
- Progressive paralysis,
- Cardiac failure,
- Respiratory failure.
Coma, or terminal phase. This phase is characterized by generalized flaccid paralysis. Eventually, the patient enters into a coma, then death. Mortality Rates Rabies is usually 100% fatal if untreated. |
