Antibodies in non-vaccinated dogs : a field study on rabies in dogs in Laos

Abstract: Rabies is a viral, zoonotic disease caused by a rhabdovirus. Most rabies cases occur in wild animals such as bats, foxes, raccoons, and skunks, however, any mammal can get the infection. 99% of all human cases are caused by bites from rabid dogs. Vaccination of dogs is the most effective way to prevent rabies in people. Each year, approximately 55,000 people die from rabies, and more than 95% of these mortalities take place in Asia and Africa. According to previous research, rabies is 100% fatal once clinical symptoms have shown. However, studies have now shown apparently healthy, non-rabies vaccinated dogs, other domestic animals, and other wild mammals seropositive for rabies in Brazil, Kenya, Nigeria, Haiti, and the US among other countries. This study was conducted in Bolikhamsai province, Vientiane province, and Vientiane capital in Laos. Rabies antibody levels in apparently healthy and non-rabies-vaccinated dogs were investigated in order to identify dogs that may have been exposed to the rabies virus and survived. Our study found 35.6% seropositivity for rabies antibodies in Laos, which is a noticeably higher percentage than in an earlier study in Laos where they found 23.7% seropositivity (Fogelberg 2020). The results are also significantly higher compared to other studies in Kenya, Nigeria, and Haiti where they found 20%, 16.1%, and 9.3% seropositivity, respectively (Wosu & Anyanwu 1990; Kitala et al. 2001; Smith et al. 2019). When using the lab method for rabies antibodies, there is no way of knowing if these antibodies derive from rabies infection or rabies vaccination. If the measured antibodies in this study do derive from a previous rabies infection and not rabies vaccination, this means that there are many dogs in Laos that survive rabies infection, many more than previously thought. Even though this study does not provide absolute proof, it contributes to the research on rabies and its serological responses. In conclusion, further research and work need to be done both in Laos and more importantly, in other countries. This is to receive a deeper understanding of the serological levels of rabies antibodies in apparently healthy and non-rabies-vaccinated dogs, and therefore continue to challenge the previous belief that rabies is a 100% deadly disease once clinical symptoms have shown.