Filoviruses, including Ebolavirus and Marburgvirus, pose significant threats to public health and species conservation by causing hemorrhagic fever outbreaks with high mortality rates. Since the ...first outbreak in 1967, their origins, natural history, and ecology remained elusive until recent studies linked them through molecular, serological, and virological studies to bats. We review the ecology, epidemiology, and natural history of these systems, drawing on examples from other bat-borne zoonoses, and highlight key areas for future research. We compare and contrast results from ecological and virological studies of bats and filoviruses with those of other systems. We also highlight how advanced methods, such as more recent serological assays, can be interlinked with flexible statistical methods and experimental studies to inform the field studies necessary to understand filovirus persistence in wildlife populations and cross-species transmission leading to outbreaks. We highlight the need for a more unified, global surveillance strategy for filoviruses in wildlife, and advocate for more integrated, multi-disciplinary approaches to understand dynamics in bat populations to ultimately mitigate or prevent potentially devastating disease outbreaks.
Undiscovered Bat Hosts of Filoviruses Han, Barbara A; Schmidt, John Paul; Alexander, Laura W ...
PLoS neglected tropical diseases,
07/2016, Letnik:
10, Številka:
7
Journal Article
Recenzirano
Odprti dostop
Ebola and other filoviruses pose significant public health and conservation threats by causing high mortality in primates, including humans. Preventing future outbreaks of ebolavirus depends on ...identifying wildlife reservoirs, but extraordinarily high biodiversity of potential hosts in temporally dynamic environments of equatorial Africa contributes to sporadic, unpredictable outbreaks that have hampered efforts to identify wild reservoirs for nearly 40 years. Using a machine learning algorithm, generalized boosted regression, we characterize potential filovirus-positive bat species with estimated 87% accuracy. Our model produces two specific outputs with immediate utility for guiding filovirus surveillance in the wild. First, we report a profile of intrinsic traits that discriminates hosts from non-hosts, providing a biological caricature of a filovirus-positive bat species. This profile emphasizes traits describing adult and neonate body sizes and rates of reproductive fitness, as well as species' geographic range overlap with regions of high mammalian diversity. Second, we identify several bat species ranked most likely to be filovirus-positive on the basis of intrinsic trait similarity with known filovirus-positive bats. New bat species predicted to be positive for filoviruses are widely distributed outside of equatorial Africa, with a majority of species overlapping in Southeast Asia. Taken together, these results spotlight several potential host species and geographical regions as high-probability targets for future filovirus surveillance.
Following a proposal made by the French and German Ministers for Foreign Affairs at the November 2020 Paris Peace Forum, 4 global partners, the Food and Agriculture Organization (FAO), the World ...Organization for Animal Health (OIE), the United Nations Environment Programme (UNEP), and the World Health Organization (WHO), in May 2021 established the interdisciplinary One Health High-Level Expert Panel (OHHLEP) (https://www.who.int/groups/one-health-high-level-expert-panel) to enhance their cross-sectoral collaboration. There is no shortage of “One Health” definitions in the published literature and among institutions and organizations. ...an immediate priority for OHHLEP was to develop consensus around a working definition as a solid basis to support a common understanding among the panel members and the partner organizations. Key underlying principles including 1. equity between sectors and disciplines; 2. sociopolitical and multicultural parity (the doctrine that all people are equal and deserve equal rights and opportunities) and inclusion and engagement of communities and marginalized voices; 3. socioecological equilibrium that seeks a harmonious balance between human–animal–environment interaction and acknowledging the importance of biodiversity, access to sufficient natural space and resources, and the intrinsic value of all living things within the ecosystem; 4. stewardship and the responsibility of humans to change behavior and adopt sustainable solutions that recognize the importance of animal welfare and the integrity of the whole ecosystem, thus securing the well-being of current and future generations; and 5. transdisciplinarity and multisectoral collaboration, which includes all relevant disciplines, both modern and traditional forms of knowledge and a broad representative array of perspectives. PLoS Pathog 18(6): e1010537. https://doi.org/10.1371/journal.ppat.1010537 About the Authors: One Health High-Level Expert Panel (OHHLEP) Wiku B. Adisasmito Affiliation: Universitas Indonesia, Depok, West Java, Indonesia Salama Almuhairi Affiliation: National Emergency Crisis and Disasters Management Authority, Abu Dhabi, United Arab Emirates Casey Barton Behravesh Affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America Pépé Bilivogui Affiliation: World Health Organization, Guinea Country Office, Conakry, Guinea Salome A. Bukachi Affiliation: Institute of Anthropology, Gender and African Studies, University of Nairobi, Nairobi, Kenya Natalia Casas Affiliation: National Ministry of Health, Autonomous City of Buenos Aires, Argentina Natalia Cediel Becerra Affiliation: School of Agricultural Sciences, Universidad de La Salle, Bogotá, Colombia Dominique F. Charron Affiliation: International Development Research Centre, Ottawa, Canada Abhishek Chaudhary Affiliation: Indian Institute of Technology (IIT), Kanpur, India Janice R. Ciacci Zanella Affiliation: Brazilian Agricultural Research Corporation (Embrapa), Embrapa Swine and Poultry, Concórdia, Santa Catarina, Brazil Andrew A. Cunningham Affiliation: Institute of Zoology, Zoological Society of London, London, United Kingdom Osman Dar Affiliations Global Operations Division, United Kingdom Health Security Agency, London, United Kingdom, Global Health Programme, Chatham House, Royal Institute of International Affairs, London, United Kingdom Nitish Debnath Affiliation: Fleming Fund Country Grant to Bangladesh, DAI Global, Dhaka, Bangladesh Baptiste Dungu Affiliations Afrivet B M, Pretoria, South Africa, Faculty of Veterinary Science, University of Kinshasa, Kinshasa, Democratic Republic Congo Elmoubasher Farag Affiliation: Ministry of Public Health, Health Protection & Communicable Diseases Division, Doha, Qatar George F. Gao Affiliation: Chinese Center for Disease Control and Prevention, Beijing, People’s Republic of China David T. S. Hayman Affiliation: Molecular Epidemiology and Public Health Laboratory, Massey University, Palmerston North, New Zealand Margaret Khaitsa Affiliation: Mississippi State University, Starkville, Mississippi,
Filoviruses Ebolavirus (EBOV) and Marburgvirus (MARV) cause haemorrhagic fevers with high mortality rates, posing significant threats to public health. To understand transmission into human ...populations, filovirus dynamics within reservoir host populations must be understood. Studies have directly linked filoviruses to bats, but the mechanisms allowing viral persistence within bat populations are poorly understood. Theory suggests seasonal birthing may decrease the probability of pathogen persistence within populations, but data suggest MARV may persist within colonies of seasonally breeding Egyptian fruit bats, Rousettus aegyptiacus. I synthesize available filovirus and bat data in a stochastic compartmental model to explore fundamental questions relating to filovirus ecology: can filoviruses persist within isolated bat colonies; do critical community sizes exist; and how do host–pathogen relationships affect spillover transmission potential? Synchronous annual breeding and shorter incubation periods did not allow filovirus persistence, whereas bi-annual breeding and longer incubation periods, such as reported for Egyptian fruit bats and EBOV in experimental studies, allowed persistence in colony sizes often found in nature. Serological data support the findings, with bats from species with two annual birth pulses more likely to be seropositive (odds ratio (OR) 4.4, 95% confidence interval (CI) 2.5–8.7) than those with one, suggesting that biannual birthing is necessary for filovirus persistence.
Ebolaviruses (EBOV) (family Filoviridae) cause viral hemorrhagic fevers in humans and non-human primates when they spill over from their wildlife reservoir hosts with case fatality rates of up to ...90%. Fruit bats may act as reservoirs of the Filoviridae. The migratory fruit bat, Eidolon helvum, is common across sub-Saharan Africa and lives in large colonies, often situated in cities. We screened sera from 262 E. helvum using indirect fluorescent tests for antibodies against EBOV subtype Zaire. We detected a seropositive bat from Accra, Ghana, and confirmed this using western blot analysis. The bat was also seropositive for Lagos bat virus, a Lyssavirus, by virus neutralization test. The bat was fitted with a radio transmitter and was last detected in Accra 13 months after release post-sampling, demonstrating long-term survival. Antibodies to filoviruses have not been previously demonstrated in E. helvum. Radio-telemetry data demonstrates long-term survival of an individual bat following exposure to viruses of families that can be highly pathogenic to other mammal species. Because E. helvum typically lives in large urban colonies and is a source of bushmeat in some regions, further studies should determine if this species forms a reservoir for EBOV from which spillover infections into the human population may occur.
Bat flight and zoonotic viruses O'Shea, Thomas J; Cryan, Paul M; Cunningham, Andrew A ...
Emerging infectious diseases,
05/2014, Letnik:
20, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Bats are sources of high viral diversity and high-profile zoonotic viruses worldwide. Although apparently not pathogenic in their reservoir hosts, some viruses from bats severely affect other ...mammals, including humans. Examples include severe acute respiratory syndrome coronaviruses, Ebola and Marburg viruses, and Nipah and Hendra viruses. Factors underlying high viral diversity in bats are the subject of speculation. We hypothesize that flight, a factor common to all bats but to no other mammals, provides an intensive selective force for coexistence with viral parasites through a daily cycle that elevates metabolism and body temperature analogous to the febrile response in other mammals. On an evolutionary scale, this host-virus interaction might have resulted in the large diversity of zoonotic viruses in bats, possibly through bat viruses adapting to be more tolerant of the fever response and less virulent to their natural hosts.
Rabies virus kills tens of thousands of people globally each year, especially in resource-limited countries. Yet, there are genetically- and antigenically-related lyssaviruses, all capable of causing ...the disease rabies, circulating globally among bats without causing conspicuous disease outbreaks. The species richness and greater genetic diversity of African lyssaviruses, along with the lack of antibody cross-reactivity among them, has led to the hypothesis that Africa is the origin of lyssaviruses. This hypothesis was tested using a probabilistic phylogeographical approach. The nucleoprotein gene sequences from 153 representatives of 16 lyssavirus species, collected between 1956 and 2015, were used to develop a phylogenetic tree which incorporated relevant geographic and temporal data relating to the viruses. In addition, complete genome sequences from all 16 (putative) species were analysed. The most probable ancestral distribution for the internal nodes was inferred using three different approaches and was confirmed by analysis of complete genomes. These results support a Palearctic origin for lyssaviruses (posterior probability = 0.85), challenging the 'out of Africa' hypothesis, and suggest three independent transmission events to the Afrotropical region, representing the three phylogroups that form the three major lyssavirus clades.
Bats as Viral Reservoirs Hayman, David T.S
Annual review of virology,
09/2016, Letnik:
3, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Bats are hosts of a range of viruses, including ebolaviruses, and many important human viral infections, such as measles and mumps, may have their ancestry traced back to bats. Here, I review viruses ...of all viral families detected in global bat populations. The viral diversity in bats is substantial, and viruses with all known types of genomic structures and replication strategies have been discovered in bats. However, the discovery of viruses is not geographically even, with some apparently undersampled regions, such as South America. Furthermore, some bat families, including those with global or wide distributions such as
Emballonuridae
and
Miniopteridae
, are underrepresented on viral databases. Future studies, including those that address these sampling gaps along with those that develop our understanding of viral-host relationships, are highlighted.
Tropical forests are undergoing land use change in many regions of the world, including the African continent. Human populations living close to forest margins fragmented and disturbed by ...deforestation may be particularly exposed to zoonotic infections because of the higher likelihood for humans to be in contact with disease reservoirs. Quantitative analysis of the nexus between deforestation and the emergence of Ebola virus disease (EVD), however, is still missing. Here we use land cover change data in conjunction with EVD outbreak records to investigate the association between recent (2004-2014) outbreaks in West and Central Africa, and patterns of land use change in the region. We show how in these EVD outbreaks the index cases in humans (i.e. spillover from wildlife reservoirs) occurred mostly in hotspots of forest fragmentation.
Cryptosporidium
is one of the most common causes of diarrhoea around the world. Successful management and prevention of this infectious disease requires knowledge of the diversity of species and ...subtypes causing human disease. We use sequence data from 2598 human faecal samples collected during an 11-year period (2009–2019) to better understand the impact of different species and subtypes on public health and to gain insights into the variation of human cryptosporidiosis in New Zealand. Human cryptosporidiosis in New Zealand is caused by a high diversity of species and subtypes. Six species cause human disease in New Zealand:
C. hominis
,
C. parvum
,
C. cuniculus
,
C. erinacei
,
C. meleagridis
and
C. tyzzeri
. Sequence analysis of the gp60 gene identified 16 subtype families and 101 subtypes.
Cryptosporidium hominis
IbA10G2 and
C. parvum
IIaA18G3R1 were the most frequent causes of human cryptosporidiosis with 27% and 29% of infections, respectively.
Cryptosporidium hominis
presented a peak of notified human cases during autumn (March–May) whereas most cases of human cryptosporidiosis caused by
C. parvum
are found during the calving and lambing season in spring (September–November). We also reported some subtypes that have been rarely detected in other countries such as IbA20G2 and IIoA13G1 and a low prevalence of the hypertransmissible and virulent IIaA15G2R1. This study provides insight into the variability of cryptosporidiosis in New Zealand essential for disease management and surveillance to prevent the introduction or spread of new species and subtypes in the country.
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