Implications of bacterial, viral and mycotic microorganisms in vultures for wildlife conservation, ecosystem services and public health

Abstract

The effects that microorganisms (bacteria, viruses and fungi) have on their hosts remain unexplored for most vulture species. This is especially relevant for vultures, as their diet consists of carcasses in various stages of decomposition, which are breeding grounds for potentially pathogenic microorganisms. Here we review current knowledge of bacterial, viral and mycotic microorganisms present in wild vultures. We consider their potential to cause disease in vultures and whether this poses any population‐level threats. Furthermore, we address the question of whether vultures may act as disease spreaders or mitigators. We found 76 articles concerning bacterial, viral and mycotic microorganisms present in 13 vulture species, 57 evaluating bacteria, 13 evaluating viruses and six evaluating mycotic microorganisms. These studies come from all continents where vultures are present, but mainly from Europe and North America, and the most studied species was the Griffon Vulture Gyps fulvus. We found that vultures are colonized by zoonotic pathogens, and even host‐specific human pathogens. Some recorded bacteria showed multi‐antibiotic resistance, especially those that can be associated with anthropogenic food subsides such as supplementary feeding stations. We found evidence that vulture health can be affected by some microorganisms, producing a wide array of clinical alterations that have the potential to influence mortality risk and fitness. We did not find clear scientific evidence that vultures play an epidemiological role spreading microorganisms to humans and other species. However, there is evidence that vultures could prevent the spread of infectious diseases through their removal of decomposing organic material. The evaluation of vulture exposure to microorganisms is of fundamental importance to design better conservation policies for this threatened group, which may serve a key role as ecosystem cleaners.

Blood Parasites in Sympatric Vultures: Role of Nesting Habits and Effects on Body Condition

“…A scavenger diet may expose vultures to multiple pathogens in carcasses, although several mechanisms have evolved to cope with them [ 9 , 10 , 11 ]. Vultures have many necrotizing and potentially pathogenic bacteria in their food, and gastrointestinal and skin microbiome, which may be kept at bay by a potentially highly evolved and upregulated immunity [ 11 , 12 ]. However, this balance may be broken by pollutants such as food-born pharmaceuticals, used in livestock for fighting against pathogens and their effects [ 13 , 14 , 15 , 16 ].…”

Framing of visual content shown on popular social media can affect viewers’ attitudes to threatened species

“…Vultures are among the most threatened avian groups in the world, 37,38 , and face not only threats such as poisoning with pesticides 31,39 and lead contamination 40 , but also persecution, trading of parts and food shortage 38 . This is a cause for concern given the important regulating ecosystem services that these species provide, removing organic material from the environment, which in turn could be important for public health and economy 41,42 . Most of the named threats are triggered by con ict between vultures and livestock producers 23,31 .…”

Presumed killers? Vultures, stakeholders, misperceptions, and fake news

“…Moreover, they generally have bare skin in their heads and necks which help them to avoid feather contamination when blood and flesh build up when feeding and sticking their heads inside a carcass (Böhmer, Prevoteau, Duriez, & Abourachid, 2020; del Hoyo et al, 1994, see also the thermoregulatory function hypothesis in Ward, McCafferty, Houston, & Ruxton, 2008). Their physiological adaptations, such as a low stomach pH and stable intestinal microbiome, allow them to cope with potentially pathogenic microorganisms present in their diet of decomposing flesh (Beasley, Koltz, Lambert, Fierer, & Dunn, 2015; Plaza, Blanco, & Lambertucci, 2020). These anatomical and physiological traits make vultures very well adapted to eat carrion but not to kill, depending on this food source for their survival.…”