Rabies in man is called hydrophobia. Rabies begins with prodromal symptoms such as headache, malaise, sore throat and slight fever lasting for 3–4 days. About 80% of patients complain of pain or tingling at the site of the bite.
The prodromal stage is followed by widespread excitation and stimulation of all parts of nervous system usually involving, in order, the sensory system, the motor system, the sympathetic and mental system. The patient is intolerant to noise, bright light or a cold draught of air. Aerophobia (fear of air) may be present and is considered by some to be pathognomonic of rabies. It can be elicited by fanning a current of air across the face which causes violent spasms of the pharyngeal and neck muscles.
Examinations may show increased reflexes and muscle spasms (motor) along with dilatation of the pupils and increased perspiration, salivation and lachrimation (sympathetic). Mental changes include fear of death, anger, irritability and depression.
The symptoms of human rabies are progressively aggravated and all attempts at swallowing liquid become unsuccessful. The patient may die abruptly during one of the convulsions or may pass on to the stage of paralysis and coma.
Diagnosis of Hydrophobia
A clinical diagnosis of hydrophobia can be made on the basis of history of bite by a rabid animal and characteristic signs and symptoms. Rabies can be confirmed in patients early in the illness by antigen detection using immunofluorescence of skin biopsy, and by virus isolation from saliva and other secretions.