Outbreaks and Control of Animal Rabies in Korea

Mass vaccination has led to the elimination of rabies since 2014 in South Korea

PURPOSE

Rabies is one of the most fatal diseases, but it is 100% preventable in animals by vaccination. In this study, we present the epidemiological features of, and national preventive measures against, rabies in Korea.

MATERIALS AND METHODS

Data related to rabies and the population density of raccoon dogs in Korea were collected from the Animal and Plant Quarantine Agency, the Korean Centers for Disease Control and Prevention, and the National Institute of Environmental Research. Rabies diagnosis was confirmed with a fluorescent antibody test using brain samples of animals in accordance with the procedures described by the World Organization for Animal Health. Serological assays for dogs and cattle were conducted using the fluorescent antibody virus neutralization test.

RESULTS

From 1993 to 2016, a total of seven human rabies cases and 437 animal rabies cases in five different species were reported. An increase in the distribution of bait vaccine seemed to be related to a dramatic decrease in rabies prevalence in endemic rabies regions. Two Korean provinces and the capital city, Seoul, were involved in rabies outbreaks. Korean rabies strains are most closely related to the eastern Chinese strain belonging to the Arctic-like lineage. The yearly seropositive rates ranged from 50.4% to 81.2% in dogs and from 25% to 60.5% in cattle residing in endemic rabies regions.

CONCLUSION

This study indicates that national preventive measures, including mass vaccination and distribution of bait vaccines, have contributed to a substantial decrease in the number of rabies cases in Korea.

Prophylaxis of human hydrophobia in South Korea

Domestic human hydrophobia has not been reported since the one case of 2004 in South Korea, but still a few animal rabies occur persistently since the reemerging stage of rabies from 1993. The government has made efforts to control animal rabies in many aspects, but whether prophylactic strategy for human hydrophobia is performed adequately is in question. The rate of proper post-exposure prophylaxis for animal bite case in 'high-risk region' of rabies is very low with 20% between 2011 and 2013. The National Animal Bite Patient Surveillance targeting 'high-risk region' is missing out animal bite cases who visit directly to hospitals in 'suspect-risk region' of rabies. Little data seems to exist for pre-exposure prophylaxis of domestic hydrophobia. Danger of reoccurrence of human hydrophobia always remain in South Korea. The medical personnel needs to have greater interest on the matter and the government strengthen the management system.

Comparison of four diagnostic methods for detecting rabies viruses circulating in Korea

It is essential to rapidly and precisely diagnose rabies. In this study, we evaluated four diagnostic methods, indirect fluorescent antibody test (FAT), virus isolation (VI), reverse transcriptase polymerase chain reaction (RT-PCR), and rapid immunodiagnostic assay (RIDA), to detect rabies in animal brain homogenates. Out of the 110 animal brain samples tested, 20 (18.2%) were positive for rabies according to the FAT. Compared to the FAT, the sensitivities of VI, RT-PCR, and RIDA were 100, 100, and 95%, respectively. The specificities of VI, RT-PCR and RIDA were found to be 100, 100, and 98.9%, respectively. Rabies viruses circulating in Korea were isolated and propagated in murine neuroblastoma (NG108-15) cells with titers ranging from 10^1.5 to 10^4.5 TCID₅₀/mL. Although the RIDA findings did not completely coincide with results obtained from FAT, VI, and RT-PCR, RIDA appears to be a fast and reliable assay that can be used to analyze brain samples. In summary, the results from our study showed that VI, RT-PCR, and RIDA can be used as supplementary diagnostic tools for detecting rabies viruses in both laboratory and field settings.