Viral Hyperparasitism in Bat Ectoparasites: Implications for Pathogen Maintenance and Transmission

Abstract

Humans continue to encroach on the habitats of wild animals, potentially bringing different species into contact that would not typically encounter each other under natural circumstances, and forcing them into stressful, suboptimal conditions. Stressors from unsustainable human land use changes are suspected to dramatically exacerbate the probability of zoonotic spillover of pathogens from their natural reservoir hosts to humans, both by increasing viral load (and shedding) and the interface between wildlife with livestock, pets and humans. Given their known role as reservoir hosts, bats continue to be investigated for their possible role as the origins of many viral outbreaks. However, the participation of bat-associated ectoparasites in the spread of potential pathogens requires further work to establish. Here, we conducted a comprehensive review of viruses, viral genes and other viral sequences obtained from bat ectoparasites from studies over the last four decades. This review summarizes research findings of the seven virus families in which these studies have been performed, including Paramyxoviridae, Reoviridae, Flaviviridae, Peribunyaviridae, Nairoviridae, Rhabdoviridae and Filoviridae. We highlight that bat ectoparasites, including dipterans and ticks, are often found to have medically important viruses and may have a role in the maintenance of these pathogens within bat populations.

Analysis of COI gene, prevalence, and intensity of the bat fly Cyclopodia greeffi on roosting straw-coloured fruit bat Eidolon helvum in Southwest Nigeria

“…The social habit of Eidolon helvum , implies close contact of individuals roosting together; and would suggest a higher prevalence of infestation by bat flies. The prevalence recorded for this study could be higher if some bat flies escaped during capture while the fruit bat was entangled in the mist net prior to removal into cloth bags; and also due to behavioural adaptation to reduce or eliminate bat fly transmission through auto- and allo-grooming activities ( Ramanantsalama et al, 2018 ; Tendu et al, 2022 ).…”

“…However, the mean intensity of 2.3 ± 0.2 individuals for this study is lower than the 2.8 C. greeffi recorded from Brazzaville, Congo ( Samabide and Lenga, 2018 ) for the straw-coloured fruit bat. An estimated average 1.79 nycteribiids is reported to parasitize Myotis daubentonii and Megaderma lyra bat hosts ( Tendu et al, 2022 ). Large number of ectoparasites reported for a female E. helvum weighing 220g ( Jiménez and Hazevoet, 2010 ) supports the broader range of ectoparasitic infestation (0–14 C. greeffi ) recorded during this study as compared to the lower and narrower range (0–4 C. greeffi ) per fruit bat reported earlier from Ife, Nigeria ( Otubanjo, 1985 ).…”

Bat flies: source of supplement nutrients for an endemic Malagasy fruit bat

“…Since ectoparasite consumption is beneficial for fruit bats, a possible correlation might exist between energetic adaptations in these animals and the transmission dynamics of different pathogens. Beyond the aspect that bat ectoparasites are potential carriers of pathogens, these invertebrates are also suspected to have the ability to transmit endogenous parasites between bats (Tendu et al 2022). Knowledge of such correlations remains limited and also deserves more attention.…”

Tick-borne viruses and their risk to public health in the Caribbean: Spotlight on bats as reservoirs in Cuba

“…These arthropod ectoparasites can act as vectors for transmitting pathogens, such as viruses, to humans and other mammal species [ 75 ]. Although bats may be resistant to infections with ectoparasite-borne viruses, these viruses can still be infectious or pathogenic to other mammals, including humans, and can be transmitted through incidental bites from bat ectoparasites [ 9 ].…”

“…In this context, bats, given their ecological significance, are emerging as subjects of interest in the realm of TBDs. While they play critical roles in various ecosystems, they can also be reservoirs for pathogens, especially when in association with ectoparasites like ticks [ [8] , [9] , [10] ].…”