2-10 day prodrome of fever, headache, malaise, nausea/vomiting, and paresthesias/pain at the bite site followed by delirium or paralysis; [Guerrant, p. 527]
Patients may have paresthesias and pain, and later weakness, at the site of the bite wound. The two forms of rabies are "furious" and "paralytic." The symptomatic phase lasts for 2-14 days, followed by coma and then death about 18 days after the onset of symptoms. Patients with furious rabies have increased salivation and sweating. Cardiac arrhythmias and myocarditis may precipitate congestive heart failure.
Opisthotonus is observed in patients with both rabies and tetanus, but rabies patients lack the persistent rigidity caused by tetanus toxin. [Guerrant, p. 529] In the differential diagnoses with paralytic rabies are Guillain-Barre syndrome, poliomyelitis, and transverse myelitis. [PPID, p. 1990]
FURIOUS RABIES & PARALYTIC RABIES
About 80% of cases are furious rabies. The other 20% are paralytic rabies, which affects the spinal cord and causes ascending flaccid paralysis. Patients with paralytic rabies do not have hydrophobia, hyperactivity, or seizures. [PPID, p. 1988-9] Leg weakness and cranial nerve palsies are symptoms of paralytic rabies. [Cohen, p. 1586] The ascending paralysis in paralytic rabies is similar to Guillain-Barre syndrome. [ID, p. 1434]
Animals infected include wild and domestic Canidae: dogs, foxes, coyotes, wolves, and jackals; also bats, skunks, raccoons, mongooses, cats, and other mammals. Rarely infected are rabbits, squirrels, chipmunks, rats, mice, and opossums. Thought to occur very rarely: 1.) After saliva contact with a break in the skin or mucous membranes; 2.) Airborne transmission in bat caves or in the laboratory; [CCDM, p. 499] ". . . rabies transmission to laboratory personnel has been reported in vaccine production and research facilities after exposure to high-titered infectious aerosols. Theoretically, rabies may be transmitted to health care personnel from exposures (bite and nonbite) to saliva from infected patients, but no cases have been documented after these types of exposures." [Guidelines for Infection Control in Health Care Personnel. CDC. 1998] "During 1990--2000, a total of 24 (75%) of 32 U.S. human rabies cases were caused by bat-associated rabies virus variants. In 22 (92%) of these cases, no documentation of a bite existed; however, this does not mean that a typical bite exposure did not take place. Instead, such a history was not uncovered during presentation or case investigation." [MMWR. January 23, 2004 / 53(02);33-35] Dog rabies in the US was brought under control in the 1950s. The few cases per year in the US are now caused mostly by bats. Raccoon rabies is still reported on the east coast from Florida to South Carolina. Canine rabies is endemic in the developing world. [Cecil, p. 2378] Cases of skunk and fox rabies occur in specific localities of the US. [Harrison ID, p. 1024]
See Table 2 in Merck Manual: "Rabies Postexposure Prophylaxis." Immunizations should be offered to long-term travelers in endemic areas and to others in high-risk jobs. [CCDM, p. 501] Previously vaccinated patients should not receive rabies immune globulin (RIG). [Harrison ID, p. 1029] The major reservoirs are carnivores and bats. All mammals (mainly terrestrial carnivores & bats) are thought to be susceptible to infection. "Bat bites anywhere in the world are a cause of concern and an indication for prophylaxis." [CDC Travel, p. 287]
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