Clinical features of dog- and bat-acquired rabies in humans

Clinical differences in rabies due to canine and bat rabies virus variants have been noted, but no detailed studies have been reported to support these observations.

Using the Morbidity and Mortality Weekly Report and PubMed, we identified 142 case reports of rabies from North America, South America, Europe, Africa, and Asia. We systematically abstracted 126 selected data elements and compared clinical features and investigation results in dog- and bat-acquired cases of rabies.

Survivors and cases acquired from aerosolized viral exposure or tissue/organ transplant were excluded (n = 20). Of 122 cases, 49 (40.2%) were dog-acquired and 54 (44.3%) were bat-acquired. Bat-acquired cases of rabies were more often misdiagnosed and lacked a bite history. Encephalopathy, hydrophobia, and aerophobia were more common in dog-acquired rabies. Abnormal cranial nerve, motor, and sensory examinations, tremor, myoclonus, local sensory symptoms, symptoms at the exposure site, and local symptoms in the absence of a bite or scratch were more common in patients with bat-acquired rabies, as was increased cerebrospinal fluid protein (P = .031). Patients with paralytic rabies had longer survival times than those with encephalitic rabies, and also had shorter incubation periods if they had received postexposure prophylaxis.

Clinical differences in dog- and bat-acquired rabies may reflect differences in the route of viral spread of rabies virus variants in the nervous system, although certain variants could cause more severe dysfunction in neuronal subpopulations. Recognition that bat-acquired rabies may present with different clinical manifestations than dog-acquired rabies may help improve the early diagnosis of rabies.