Yellow fever in non-human primates : a veterinary guide from a One Health perspective

Abstract

SIMPLE SUMMARY : Yellow fever (YF) is a serious viral arthropod-borne disease in Africa and South America, affecting both humans and non-human primates (NHPs). The susceptibility of different NHP species to YF varies greatly, with the largest mortality events reported in howler monkeys (genus Alouatta). Neotropical primates (NTPs) often show non-specific clinical signs, if any, before dying. These outbreaks in NTPs may be used to signal potential outbreaks in humans. For these early warning systems to be effective, accurate and reliable diagnostic techniques that work under field settings are essential. There are no YF-specific treatments available, but the human 17DD-vaccine effectively prevents the disease in NHPs. Prophylaxis should be based on a One Health perspective that recognizes the intricate interplay between human health, primate health, and the environment. Consequently, mitigation strategies continue to rely more and more on vector control, preferably using eco-friendly methods. Climate change and human activities, along with impact on local ecology, are assumed to increase the risk of YF transmission in the next decades. This underscores the importance of future research, which should focus on refining YF monitoring systems and developing immunization techniques that are applicable to wild NTP populations.ABSTRACT : Yellow fever (YF) causes severe morbidity and mortality in Africa and South America. It is an arthropod-borne viral disease endemic to tropical regions of Africa and South America. Yellow fever virus (YFV) is transmitted by mosquitoes and frequently affects both non-human primates (NHPs) and humans. Neotropical primates (NTPs) are generally more severely afflicted by YFV than African primates. Asian primates appear not to be susceptible to this disease. Susceptibility varies among NTP species: asymptomatic infections are described in some NTP species, whereas severe epizootic mortality events are described in others. The genus Alouatta (howler monkeys) is considered to be the most susceptible among the NTPs. Epizootic events resulting in the death of thousands of NTPs have been recorded in recent history. As a result, YFV poses a threat to the survival of some NTP species. In most cases, NTPs are found dead without showing prior clinical signs. In cases where clinical signs are observed, they are mostly non-specific. Due to their high susceptibility, epizootic events in NTPs are used as epidemiological predictors for human YF outbreaks. YFV infection may be diagnosed by means of virus isolation, reverse transcription polymerase chain reaction, serology, histopathology, or immunohistochemistry. Animals that survive the disease develop neutralizing antibodies to YFV. Currently, no specific treatment is available. Sustained YF control strategies must rely on surveillance and accurate diagnostics to allow for early detection of outbreaks and rapid implementation of control measures. Prophylaxis should be based on a One Health perspective that recognizes the intricate interplay between human health, primate health, and the environment. Vaccines for YF are available, with the human 17DD vaccine effectively preventing disease in primates. However, mitigation strategies continue to rely more and more on vector control, preferably using eco-friendly methods. Climate change and human activities, and their impact on local ecology, are assumed to increase the risk of YF transmission in the next decades.