How to Diagnose Rabies

Rabies is a viral infection of the central nervous system. It is usually caused by a member of the Lyssavirus genus and can be found anywhere except for the Antarctic and Australia. Rabies is infectious and fatal once the symptoms develop. Rabies has historically been transmitted by the bite of an infected animal but non-bite exposure is common in the United States. The following steps will show how to diagnose rabies.

Instructions

• 1

  Suspect rabies when the patient has been bitten by an animal. It is virtually impossible to diagnose rabies in the early stage without an exposure history.

• 2

  Observe the symptoms of the neurologic stage of rabies. These include aphasia, changes in mental status, hyperactivity, lack of coordination and paralysis.

• 3

  Expect the late stage of rabies to be marked by hypotension, disseminated intravascular coagulation, cardiac arrhythmias, cardiac arrest, coma and death.

• 4

  Conduct laboratory studies of the cerebrospinal fluid (CSF) when rabies is suspected. The protein level is usually elevated and the red and white blood counts may be slightly high as well.

• 5

  Isolate the rabies virus from the CSF, saliva, serum and skin. The rabies antibodies also can be measured in patients that haven't been vaccinated after seven days from the onset of symptoms. The CSF or serum is extracted with a lumbar puncture. An antibody titer higher than 5 makes the diagnosis. The rabies antigen can be detected in the brain or nerves near hair follicles in the neck with a skin biopsy.