Bats as putative Zaire ebolavirus reservoir hosts and their habitat suitability in Africa

Abstract

the genus Ebolavirus comprises some of the deadliest viruses for primates and humans and associated disease outbreaks are increasing in Africa. Different evidence suggests that bats are putative reservoir hosts and play a major role in the transmission cycle of these filoviruses. Thus, detailed knowledge about their distribution might improve risk estimations of where future disease outbreaks might occur. A MaxEnt niche modelling approach based on climatic variables and land cover was used to investigate the potential distribution of 9 bat species associated to the Zaire ebolavirus. this viral species has led to major Ebola outbreaks in Africa and is known for causing high mortalities. Modelling results suggest suitable areas mainly in the areas near the coasts of West Africa with extensions into Central Africa, where almost all of the 9 species studied find suitable habitat conditions. Previous spillover events and outbreak sites of the virus are covered by the modelled distribution of 3 bat species that have been tested positive for the virus not only using serology tests but also pcR methods. Modelling the habitat suitability of the bats is an important step that can benefit public information campaigns and may ultimately help control future outbreaks of the disease. Today, many infectious diseases occurring in humans are zoonotic and originate from infected wild animals 1. Among these emerging diseases, diseases caused by filoviruses pose major health threats, since these viruses belong to the most lethal primate pathogens with average death rates of 50% 2,3. In recent years, the genus Ebolavirus has gained much attention. The genus Ebolavirus was first identified in 1976 in the area of present-day Democratic Republic of the Congo (near the Ebola River) and the species of this genus are endemic in at least 14 African countries today. Until today, five viral species of the genus Ebolavirus, namely the Zaire ebolavirus (ZEBOV), the Sudan ebolavirus, the Taï Forest ebolavirus, the Bundibugyo ebolavirus and the Reston ebolavirus are known. While the first four species are assumed to be endemic to Africa and have led to numerous disease outbreaks in several African countries so far 4,5 , Reston ebolavirus is probably native to Asian countries, e.g. the Philippines and China 3,6,7. Similar to the Marburg virus, the different species within the genus Ebolavirus, except Reston ebolavirus, cause haemorrhagic fever, which includes various symptoms like fever, vomiting, diarrhoea and muscle pain 4,8. Besides their common symptoms, the five viral species differ in their pathogenicity, from asymptotic infections caused by Reston ebolavirus in humans to high mortality rates of up to 77-88% in case of ZEBOV infections 6,9-11. The largest outbreak of the Ebola virus disease (EVD) until today occurred in Western Africa between 2014 and 2016. Starting in December 2013 with a probable spillover of the virus from infected bats 12 , the epidemic spread to other parts of Africa. The largest impact and number of EVD cases were reco...

Common Themes in Zoonotic Spillover and Disease Emergence: Lessons Learned from Bat- and Rodent-Borne RNA Viruses

“…In addition, although bats are reservoirs of several viruses that have been responsible for serious outbreaks, models have shown that viruses harbored by bats are no more likely to be zoonotic than viruses that are harbored or transmitted by rodents or other hosts [ 19 ]. For some viruses in the genus Ebolavirus , bats are the presumptive main reservoir, but have yet to be definitively confirmed [ 34 , 35 , 36 , 37 ].…”

“…Extensive searches have been conducted to identify the reservoir, but it remains elusive [ 216 , 217 ]. Bats have been proposed to harbor the viruses but have not been proven to be the reservoir [ 34 , 37 ]. While the reservoir for the virus has yet to be identified, numerous outbreaks have occurred following humans handling animals such as primates (chimpanzees and gorillas) and antelopes (duikers) and their carcasses [ 218 , 219 , 220 ].…”

Environmental Risk Assessment for rVSVΔG-ZEBOV-GP, a Genetically Modified Live Vaccine for Ebola Virus Disease

“…Shown are the enzootic cycles (i.e., the predominant, long-term natural host reservoirs of the virus and transmission vectors) and epizootic cycles (i.e., spillover of the virus into other susceptible species and/or alternative transmission vectors). The main natural host reservoir of Ebola virus is thought to be certain species of Old World fruit bats, but the virus is capable of transmission to many other mammalian species [ 1 , 7 , 8 , 9 , 10 ]. The natural host reservoir of VSV is thought to be mainly small rodents, such as deer mice, with sandflies acting as transmission vectors; however, VSV is also capable of infecting many other animal species and can be transmitted via other insects [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ].…”

“…EVD is a zoonotic disease, with EBOV believed to be transmitted to human index cases through close contact with bodily fluids of infected, rainforest-dwelling mammals. Prevailing evidence suggests that fruit bats are the predominant natural host reservoir of EBOV, with other species such as rodents, porcupines, pigs, dogs, non-human primates, and also humans merely serving as accidental spillover hosts ( Figure 1 a) [ 1 , 7 , 8 , 9 , 10 ]. However, once the virus has successfully infected an index patient, EBOV readily spreads human to human by direct contact with bodily fluids/tissues of EVD patients or with fomites contaminated with such infectious materials [ 1 ].…”

Learning from Bats to Escape from Potent or Severe Viral Infections

“…Fruit bats, including Hypsignathus monstrosus, Epomops franqueti, and Myonycteris torquate have also been suggested as potential reservoirs for Zaire Ebolavirus [12,17]. In addition to these zoonotic viral infections, bats also serve as potential reservoirs for other viruses responsible for infections in humans that include Nipah, Hendra, Marburg, Hepadna (able to infect human hepatocytes), and Lyssa viruses etc.…”