scholarly journals Bats host the most virulent—but not the most dangerous—zoonotic viruses

2021 ◽  
Author(s):  
Sarah Guth ◽  
Nardus Mollentze ◽  
Katia Renault ◽  
Daniel Streicker ◽  
Elisa Visher ◽  
...  
Keyword(s):  
Case Fatality ◽  
Human Case ◽  
Host Population ◽  
Reservoir Host ◽  
Human Populations ◽  
Animal Reservoir ◽  
Human Mortality ◽  
Zoonotic Viruses ◽  
Zoonotic Risk ◽  
Context Specific

Identifying virus characteristics associated with the largest public health impacts on human populations is critical to informing zoonotic risk assessments and surveillance strategies. Efforts to assess "zoonotic risk" often use trait-based analyses to identify which viral and reservoir host groups are most likely to source zoonoses but have not fully addressed how and why the impacts of zoonotic viruses vary in terms of disease severity ('virulence'), capacity to spread within human populations ('transmissibility'), or total human mortality ('death burden'). We analyzed trends in human case fatality rates, transmission capacities, and total death burdens across a comprehensive dataset of mammalian and avian zoonotic viruses. Bats harbor the most virulent zoonotic viruses even when compared to birds, which alongside bats, have been hypothesized to be "special" zoonotic reservoirs due to molecular adaptations that support the physiology of flight. Reservoir host groups more closely related to humans—in particular, Primates—harbor less virulent, but more highly transmissible viruses. Importantly, disproportionately high human death burden, arguably the most important metric of zoonotic risk, is not associated with any animal reservoir, including bats. Our data demonstrate that mechanisms driving death burdens are diverse and often contradict trait-based predictions. Ultimately, total human mortality is dependent on context-specific epidemiological dynamics, which are shaped by a combination of viral traits and conditions in the animal host population and across and beyond the human-animal interface. Understanding the conditions that predict high zoonotic burden in humans will require longitudinal studies of epidemiological dynamics in wildlife and human populations.

scholarly journals Climate change accelerates winter transmission of a zoonotic pathogen

AMBIO ◽  
2021 ◽  
Author(s):  
Saana Sipari ◽  
Hussein Khalil ◽  
Magnus Magnusson ◽  
Magnus Evander ◽  
Birger Hörnfeldt ◽  
...  
Keyword(s):  
Climate Change ◽  
Host Population ◽  
Reservoir Host ◽  
Pathogen Transmission ◽  
Myodes Glareolus ◽  
Zoonotic Pathogen ◽  
The North ◽  
Bank Voles ◽  
Zoonotic Risk ◽  
Climate Change Effect

AbstractMany zoonotic diseases are weather sensitive, raising concern how their distribution and outbreaks will be affected by climate change. At northern high latitudes, the effect of global warming on especially winter conditions is strong. By using long term monitoring data (1980–1986 and 2003–2013) from Northern Europe on temperature, precipitation, an endemic zoonotic pathogen (Puumala orthohantavirus, PUUV) and its reservoir host (the bank vole, Myodes glareolus), we show that early winters have become increasingly wet, with a knock-on effect on pathogen transmission in its reservoir host population. Further, our study is the first to show a climate change effect on an endemic northern zoonosis, that is not induced by increased host abundance or distribution, demonstrating that climate change can also alter transmission intensity within host populations. Our results suggest that rainy early winters accelerate PUUV transmission in bank voles in winter, likely increasing the human zoonotic risk in the North.

scholarly journals Reservoir host immunology and life history shape virulence evolution in zoonotic viruses

2021 ◽  
Author(s):  
Cara E Brook ◽  
Carly Rozins ◽  
Sarah Guth ◽  
Michael Boots
Keyword(s):  
Life History ◽  
Severe Disease ◽  
Case Fatality ◽  
Population Level ◽  
Mechanistic Explanation ◽  
Reservoir Host ◽  
Virulence Evolution ◽  
Zoonotic Viruses ◽  
Future Work ◽  
Modelling Approach

Future pandemic risk management requires better understanding of the mechanisms that determine the virulence of emerging zoonotic viruses. Bats host viruses that cause higher case fatality rates upon spillover to humans than those derived from any other mammal, suggesting that reservoir host immunological and life history traits may be important drivers of cross-species virulence. Using a nested population-level and within-host modelling approach, we generate virulence predictions for viral zoonoses derived from diverse mammalian reservoirs, successfully recapturing corresponding virus-induced human mortality rates from the literature. Our work offers a mechanistic explanation for the virulence of bat-borne zoonoses and, more generally, demonstrates how key differences in reservoir host longevity, tolerance, and population density impact the evolution of viral traits that generate severe disease following spillover to humans. We provide a theoretical framework that offers a series of testable questions and hypotheses designed to stimulate future work comparing cross-species virulence evolution in zoonotic viruses derived from diverse mammalian hosts.

scholarly journals From Protein to Pandemic: The Transdisciplinary Approach Needed to Prevent Spillover and the Next Pandemic

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1298
Author(s):  
Raina K. Plowright ◽  
Peter J. Hudson
Keyword(s):  
Immune Responses ◽  
Host Population ◽  
Reservoir Host ◽  
Innate Immune ◽  
Receptor Protein ◽  
The Novel ◽  
Innate Immune Responses ◽  
Transdisciplinary Approach ◽  
Sequence Of Events ◽  
Global Spread

Pandemics are a consequence of a series of processes that span scales from viral biology at 10−9 m to global transmission at 106 m. The pathogen passes from one host species to another through a sequence of events that starts with an infected reservoir host and entails interspecific contact, innate immune responses, receptor protein structure within the potential host, and the global spread of the novel pathogen through the naive host population. Each event presents a potential barrier to the onward passage of the virus and should be characterized with an integrated transdisciplinary approach. Epidemic control is based on the prevention of exposure, infection, and disease. However, the ultimate pandemic prevention is prevention of the spillover event itself. Here, we focus on the potential for preventing the spillover of henipaviruses, a group of viruses derived from bats that frequently cross species barriers, incur high human mortality, and are transmitted among humans via stuttering chains. We outline the transdisciplinary approach needed to prevent the spillover process and, therefore, future pandemics.

scholarly journals Immunogenicity and structures of a rationally designed prefusion MERS-CoV spike antigen

2017 ◽  
Vol 114 (35) ◽  
pp. E7348-E7357 ◽  
Author(s):  
Jesper Pallesen ◽  
Nianshuang Wang ◽  
Kizzmekia S. Corbett ◽  
Daniel Wrapp ◽  
Robert N. Kirchdoerfer ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Case Fatality ◽  
Neutralizing Antibody ◽  
Human Populations ◽  
Receptor Binding Domain ◽  
Potential Mechanism ◽  
Primary Target ◽  
Humoral Immune ◽  
Receptor Recognition ◽  
Antibody Titers

Middle East respiratory syndrome coronavirus (MERS-CoV) is a lineage C betacoronavirus that since its emergence in 2012 has caused outbreaks in human populations with case-fatality rates of ∼36%. As in other coronaviruses, the spike (S) glycoprotein of MERS-CoV mediates receptor recognition and membrane fusion and is the primary target of the humoral immune response during infection. Here we use structure-based design to develop a generalizable strategy for retaining coronavirus S proteins in the antigenically optimal prefusion conformation and demonstrate that our engineered immunogen is able to elicit high neutralizing antibody titers against MERS-CoV. We also determined high-resolution structures of the trimeric MERS-CoV S ectodomain in complex with G4, a stem-directed neutralizing antibody. The structures reveal that G4 recognizes a glycosylated loop that is variable among coronaviruses and they define four conformational states of the trimer wherein each receptor-binding domain is either tightly packed at the membrane-distal apex or rotated into a receptor-accessible conformation. Our studies suggest a potential mechanism for fusion initiation through sequential receptor-binding events and provide a foundation for the structure-based design of coronavirus vaccines.

scholarly journals Epidemiology of Trypanosomiasis in Wildlife—Implications for Humans at the Wildlife Interface in Africa

2021 ◽  
Vol 8 ◽  
Author(s):  
Keneth Iceland Kasozi ◽  
Gerald Zirintunda ◽  
Fred Ssempijja ◽  
Bridget Buyinza ◽  
Khalid J. Alzahrani ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
Significant Risk ◽  
Trypanosoma Evansi ◽  
Human Populations ◽  
Zoonotic Risk ◽  
Cross Transmission ◽  
Trypanosoma Dionisii ◽  
Animal Trypanosomiasis ◽  
Human Infections ◽  
Grazing Lands

While both human and animal trypanosomiasis continue to present as major human and animal public health constraints globally, detailed analyses of trypanosome wildlife reservoir hosts remain sparse. African animal trypanosomiasis (AAT) affects both livestock and wildlife carrying a significant risk of spillover and cross-transmission of species and strains between populations. Increased human activity together with pressure on land resources is increasing wildlife–livestock–human infections. Increasing proximity between human settlements and grazing lands to wildlife reserves and game parks only serves to exacerbate zoonotic risk. Communities living and maintaining livestock on the fringes of wildlife-rich ecosystems require to have in place methods of vector control for prevention of AAT transmission and for the treatment of their livestock. Major Trypanosoma spp. include Trypanosoma brucei rhodesiense, Trypanosoma brucei gambiense, and Trypanosoma cruzi, pathogenic for humans, and Trypanosoma vivax, Trypanosoma congolense, Trypanosoma evansi, Trypanosoma brucei brucei, Trypanosoma dionisii, Trypanosoma thomasbancrofti, Trypanosma elephantis, Trypanosoma vegrandis, Trypanosoma copemani, Trypanosoma irwini, Trypanosoma copemani, Trypanosoma gilletti, Trypanosoma theileri, Trypanosoma godfreyi, Trypansoma simiae, and Trypanosoma (Megatrypanum) pestanai. Wildlife hosts for the trypansomatidae include subfamilies of Bovinae, Suidae, Pantherinae, Equidae, Alcephinae, Cercopithecinae, Crocodilinae, Pteropodidae, Peramelidae, Sigmodontidae, and Meliphagidae. Wildlife species are generally considered tolerant to trypanosome infection following centuries of coexistence of vectors and wildlife hosts. Tolerance is influenced by age, sex, species, and physiological condition and parasite challenge. Cyclic transmission through Glossina species occurs for T. congolense, T. simiae, T. vivax, T. brucei, and T. b. rhodesiense, T. b. gambiense, and within Reduviid bugs for T. cruzi. T. evansi is mechanically transmitted, and T. vixax is also commonly transmitted by biting flies including tsetse. Wildlife animal species serve as long-term reservoirs of infection, but the delicate acquired balance between trypanotolerance and trypanosome challenge can be disrupted by an increase in challenge and/or the introduction of new more virulent species into the ecosystem. There is a need to protect wildlife, animal, and human populations from the infectious consequences of encroachment to preserve and protect these populations. In this review, we explore the ecology and epidemiology of Trypanosoma spp. in wildlife.

scholarly journals Metagenomic analysis of fecal and tissue samples from 18 endemic bat species in Switzerland revealed a diverse virus composition including potentially zoonotic viruses

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252534
Author(s):  
Isabelle Hardmeier ◽  
Nadja Aeberhard ◽  
Weihong Qi ◽  
Katja Schoenbaechler ◽  
Hubert Kraettli ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Early Detection ◽  
Disease Outbreaks ◽  
Tissue Samples ◽  
Zoonotic Virus ◽  
Non Invasive ◽  
Zoonotic Viruses ◽  
Zoonotic Risk ◽  
Generation Sequencing ◽  
Diverse Virus

Many recent disease outbreaks in humans had a zoonotic virus etiology. Bats in particular have been recognized as reservoirs to a large variety of viruses with the potential to cross-species transmission. In order to assess the risk of bats in Switzerland for such transmissions, we determined the virome of tissue and fecal samples of 14 native and 4 migrating bat species. In total, sequences belonging to 39 different virus families, 16 of which are known to infect vertebrates, were detected. Contigs of coronaviruses, adenoviruses, hepeviruses, rotaviruses A and H, and parvoviruses with potential zoonotic risk were characterized in more detail. Most interestingly, in a ground stool sample of a Vespertilio murinus colony an almost complete genome of a Middle East respiratory syndrome-related coronavirus (MERS-CoV) was detected by Next generation sequencing and confirmed by PCR. In conclusion, bats in Switzerland naturally harbour many different viruses. Metagenomic analyses of non-invasive samples like ground stool may support effective surveillance and early detection of viral zoonoses.

scholarly journals Some Epidemiological Aspects of Cutaneous Leishmaniasis in a New Focus, Central Iran

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
M. R. Yaghoobi-Ershadi ◽  
N. Marvi-Moghadam ◽  
R. Jafari ◽  
A. A. Akhavan ◽  
H. Solimani ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Primary Schools ◽  
Leishmania Major ◽  
Reservoir Host ◽  
Human Infection ◽  
Native People ◽  
Sand Fly ◽  
Animal Reservoir ◽  
Rural Districts ◽  
Tatera Indica

Following the epidemic of cutaneous leishmaniasis in Khatam County, Yazd Province, this study was carried out to determine vector, and animal reservoir host(s) and investigate the human infection during 2005-2006. Four rural districts where the disease had higher prevalence were selected. Sticky paper traps were used to collect sand flies during April to November, biweekly. Meanwhile rodents were captured using Sherman traps from August to November. Households and primary schools were visited and examined for human infection in February 2006. The parasite was detected by RAPD-PCR method. The rate of ulcers and scars among the inhabitants was 4.8% and 9.8%, respectively. Three rodent species were captured during the study:Meriones libycus, Rhombomys opimus, andTatera indica. Six sand fly species were also collected and identified; among themPhlebotomus papatasihad the highest frequency.Leishmania majorwas detected as the agent of the disease in the area. It was detected fromR. opimusand native people.

scholarly journals Evolution of Nipah Virus Infection: Past, Present, and Future Considerations

2021 ◽  
Vol 6 (1) ◽  
pp. 24
Author(s):  
Naomi Hauser ◽  
Alexis C. Gushiken ◽  
Shivakumar Narayanan ◽  
Shyam Kottilil ◽  
Joel V. Chua
Keyword(s):  
Case Fatality Rate ◽  
Nipah Virus ◽  
Case Fatality ◽  
Therapeutic Agents ◽  
Reservoir Host ◽  
Fruit Bats ◽  
Intermediate Hosts ◽  
Mode Of Transmission ◽  
Human Infections ◽  
Reservoir Hosts

Nipah virus (NiV) is a zoonotic paramyxovirus of the Henipavirus genus first identified in Malaysia in 1998. Henipaviruses have bat reservoir hosts and have been isolated from fruit bats found across Oceania, Asia, and Africa. Bat-to-human transmission is thought to be the primary mode of human NiV infection, although multiple intermediate hosts are described. Human infections with NiV were originally described as a syndrome of fever and rapid neurological decline following contact with swine. More recent outbreaks describe a syndrome with prominent respiratory symptoms and human-to-human transmission. Nearly annual outbreaks have been described since 1998 with case fatality rates reaching greater than 90%. The ubiquitous nature of the reservoir host, increasing deforestation, multiple mode of transmission, high case fatality rate, and lack of effective therapy or vaccines make NiV’s pandemic potential increasingly significant. Here we review the epidemiology and microbiology of NiV as well as the therapeutic agents and vaccines in development.

scholarly journals Evidence that Human Chlamydia pneumoniae Was Zoonotically Acquired

2009 ◽  
Vol 191 (23) ◽  
pp. 7225-7233 ◽  
Author(s):  
G. S. A. Myers ◽  
S. A. Mathews ◽  
M. Eppinger ◽  
C. Mitchell ◽  
K. K. O'Brien ◽  
...  
Keyword(s):  
Chlamydia Pneumoniae ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
Human Populations ◽  
Animal Reservoir ◽  
Single Nucleotide ◽  
Phascolarctos Cinereus ◽  
Zoonotic Infections ◽  
Conserved Genes ◽  
Animal Isolate

ABSTRACT Zoonotic infections are a growing threat to global health. Chlamydia pneumoniae is a major human pathogen that is widespread in human populations, causing acute respiratory disease, and has been associated with chronic disease. C. pneumoniae was first identified solely in human populations; however, its host range now includes other mammals, marsupials, amphibians, and reptiles. Australian koalas (Phascolarctos cinereus) are widely infected with two species of Chlamydia, C. pecorum and C. pneumoniae. Transmission of C. pneumoniae between animals and humans has not been reported; however, two other chlamydial species, C. psittaci and C. abortus, are known zoonotic pathogens. We have sequenced the 1,241,024-bp chromosome and a 7.5-kb cryptic chlamydial plasmid of the koala strain of C. pneumoniae (LPCoLN) using the whole-genome shotgun method. Comparative genomic analysis, including pseudogene and single-nucleotide polymorphism (SNP) distribution, and phylogenetic analysis of conserved genes and SNPs against the human isolates of C. pneumoniae show that the LPCoLN isolate is basal to human isolates. Thus, we propose based on compelling genomic and phylogenetic evidence that humans were originally infected zoonotically by an animal isolate(s) of C. pneumoniae which adapted to humans primarily through the processes of gene decay and plasmid loss, to the point where the animal reservoir is no longer required for transmission.

scholarly journals Hantavirus infections in The Netherlands: epidemiology and disease

1995 ◽  
Vol 114 (2) ◽  
pp. 373-383 ◽  
Author(s):  
J. Groen ◽  
M. N. Gerding ◽  
J. G. M. Jordans ◽  
J. P. Clement ◽  
J. H. M. Nieuwenhuijs ◽  
...  
Keyword(s):  
The Netherlands ◽  
Animal Species ◽  
Domestic Animal ◽  
Clethrionomys Glareolus ◽  
Human Populations ◽  
Animal Reservoir ◽  
Laboratory Findings ◽  
Transplant Patients ◽  
Forested Areas ◽  
Laboratory Workers

SummaryA serological survey for the prevalence of hantavirus infections in The Netherlands was carried out on > 10000 sera, from selected human populations, and different feral and domestic animal species. Hantavirus-specific antibodies were found in about 1% of patients suspected of acute leptospirosis, 10% of patients with acute nephropathia, and in less than 0·1% haemodialysis and renal transplant patients. Among individuals with a suspected occupational risk, 6% of animal trappers, 4% of forestry workers, 2% of laboratory workers and 0·4% of farmers were seropositive. The majority of the seropositive individuals lived in rural and forested areas. The main animal reservoir of the infection was shown to be the red bank vole (Clethrionomys glareolus). Epidemiological, clinical and laboratory findings seen in serologically confirmed human cases were similar to those associated with nephropathia epidemica.

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