Human rabies following a non-human primate bite in India

The recent review on clinical management of monkey bites in travelers was timely and informative, and highlighted the potential risk of rabies following exposure to non-human primates (NHP) in rabies-enzootic regions.1 Recently, we encountered a case of human rabies following an uncommon mode of exposure to NHP. A 45-year-old male, from a village in Andhra Pradesh, a southern state in India, presented to a local physician with 2 days history of painful involuntary contractions of pharyngeal muscles on exposure to air and liquids, causing choking. On recognition of these classical symptoms of aerophobia and hydrophobia, he was referred to the Infectious Disease Hospital. The patient had had a history of monkey bite on his left upper arm three weeks prior; he had apparently climbed a palm tree to consume toddy tapped in a pot, when he was suddenly attacked and bitten by a monkey—the exact species was not known. The patient did not seek medical advice and hence did not receive post-exposure prophylaxis (PEP). On examination, patient was found agitated, delirious and had hallucinations. He lapsed into coma and died within a day of hospital admission. Rabies virus neutralizing antibody titre by rapid fluorescent focus inhibition test (RFFIT) in his serum was 512, which was suggestive of rabies in a non vaccinated individual. Saliva was positive for rabies viral RNA by real-time PCR confirming rabies encephalitis. Laboratory confirmation can validate a clinical diagnosis, especially in patients with uncommon/unusual exposures or atypical clinical presentation and help in case closure and grief counseling of family members. Various species of NHPs are commonly seen throughout India, both in rural and urban areas. Since they are likened to Hanuman, the Hindu monkey god, they are worshipped and fed by locals, and especially thrive in and around some temple premises and tourist spots. Since most cases of rabies in India and other canine rabies endemic countries are attributed to rabid dogs, rabies acquired through exposures to NHPs is often underreported. The growing human population and encroachment of forests and wild-life habitat can increase the opportunities for human-NHP encounters. Despite an increasing population of NHPs being reported as a human menace in many urban areas in India, and several studies from animal-bite clinics frequently documenting NHP bites, few reports of rabies in NHPs or human rabies following exposure to NHPs are published from India. This can be attributed to the fact that rabies is not a notifiable disease in India and systematic surveillance for human and animal rabies does not exist. However, several instances of human rabies being acquired by western travelers visiting India have been reported. A case of human rabies in Germany has been reported to be probably related to a monkey bite he received 3 years prior to developing disease.2 A young boy in Australia developed rabies following a bite on his finger by a wild monkey on his trip to north India.3 Natural rabies infection in a NHP (Macaca mulatta) imported from India has been documented in the United Kingdom.4 As emphasized by the authors,1 monkey bites in travelers may not be rare-they accounted for 31% of injuries necessitating PEP for rabies in international travelers returning from rabies endemic countries.5 Travelers visiting rabies enzootic countries like India are often unaware of the potential risk of rabies following exposure to NHPs and hence they may not seek immediate medical care. They should be informed about these risks and the need for immediate PEP following exposure to NHPs. Pre-exposure rabies vaccination (which obviates the need for scarcely available immunoglobulin in case of a subsequent exposure) should be recommended to travelers after assessment of the potential risk on individual basis. Conflict of interest: None declared.