scholarly journals Limited overlap in RNA virome composition among rabbits and their ectoparasites reveals barriers to virus transmission

2019 ◽  
Author(s):  
Jackie E. Mahar ◽  
Mang Shi ◽  
Robyn N. Hall ◽  
Tanja Strive ◽  
Edward C. Holmes
Keyword(s):  
Rna Virus ◽  
Virus Transmission ◽  
Myxoma Virus ◽  
Gut Contents ◽  
Mechanical Transmission ◽  
The Novel ◽  
Caecal Content ◽  
Rabbit Haemorrhagic Disease ◽  
Haemorrhagic Disease

AbstractEctoparasites play an important role in virus transmission among vertebrates. However, little is known about the extent and composition of viruses that pass between invertebrates and vertebrates. In Australia, flies and fleas support the mechanical transmission of viral biological controls against wild rabbits - rabbit haemorrhagic disease virus (RHDV) and myxoma virus. We compared virome structure and composition in rabbits and these associated ectoparasites, sequencing total RNA from multiple tissues and gut contents of wild rabbits, fleas collected from these rabbits, and flies trapped sympatrically. Meta-transcriptomic analyses identified 50 novel viruses from multiple RNA virus families. Rabbits and their ectoparasites were characterised by markedly different viromes: although viral contigs from six virus families/groups were found in both rabbits and ectoparasites, none were vertebrate-associated. A novel calicivirus and picornavirus detected in rabbit caecal content were vertebrate-specific: the newly detected calicivirus was distinct from known rabbit caliciviruses, while the novel picornavirus clustered with the Sapeloviruses. Several Picobirnaviridae were also identified, falling in diverse phylogenetic positions suggestive of an association with co-infecting bacteria. The remaining viruses found in rabbits, and all those from ectoparasites, were likely associated with invertebrates, plants and co-infecting endosymbionts. While no full genomes of vertebrate-associated viruses were detected in ectoparasites, suggestive of major barriers to biological transmission with active replication, small numbers of reads from rabbit astrovirus, RHDV and other lagoviruses were present in flies. This supports the role of flies in the mechanical transmission of RHDV and implies that they may assist the spread of astroviruses.

scholarly journals Simple mathematical models for controlling COVID-19 transmission through social distancing and community awareness

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ahmed S. Elgazzar
Keyword(s):  
Mathematical Models ◽  
Virus Transmission ◽  
Small World ◽  
Vaccination Rate ◽  
The Novel ◽  
Social Distancing ◽  
Community Awareness ◽  
Sufficient Degree ◽  
And Control

Abstract The novel COVID-19 pandemic is a current, major global health threat. Up till now, there is no fully approved pharmacological treatment or a vaccine. Also, its origin is still mysterious. In this study, simple mathematical models were employed to examine the dynamics of transmission and control of COVID-19 taking into consideration social distancing and community awareness. Both situations of homogeneous and nonhomogeneous population were considered. Based on the calculations, a sufficient degree of social distancing based on its reproductive ratio is found to be effective in controlling COVID-19, even in the absence of a vaccine. With a vaccine, social distancing minimizes the sufficient vaccination rate to control the disease. Community awareness also has a great impact in eradicating the virus transmission. The model is simulated on small-world networks and the role of social distancing in controlling the infection is explained.

scholarly journals Novel Trivalent Vectored Vaccine for Control of Myxomatosis and Disease Caused by Classical and a New Genotype of Rabbit Haemorrhagic Disease Virus

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 441 ◽  
Author(s):  
Sylvia Reemers ◽  
Leon Peeters ◽  
Joyce van Schijndel ◽  
Beth Bruton ◽  
David Sutton ◽  
...  
Keyword(s):  
Disease Virus ◽  
Myxoma Virus ◽  
European Rabbit ◽  
Viral Diseases ◽  
Serological Response ◽  
Rabbit Haemorrhagic Disease Virus ◽  
Rabbit Haemorrhagic Disease ◽  
New Genotype ◽  
Vectored Vaccine ◽  
Haemorrhagic Disease

Myxoma virus (MV) and rabbit haemorrhagic disease virus (RHDV) are the major causes of lethal viral diseases in the European rabbit. In 2010, a new RHDV genotype (RHDV2) emerged in the field that had limited cross-protection with the classical RHDV (RHDV1). For optimal protection of rabbits and preventing spread of disease, a vaccine providing protection against all three key viruses would be ideal. Therefore, a novel trivalent myxoma vectored RHDV vaccine (Nobivac Myxo-RHD PLUS) was developed similar to the existing bivalent myxoma vectored RHDV vaccine Nobivac Myxo-RHD. The new vaccine contains the Myxo-RHDV1 strain already included in Nobivac Myxo-RHD and a similarly produced Myxo-RHDV2 strain. This paper describes several key safety and efficacy studies conducted for European licensing purposes. Nobivac Myxo-RHD PLUS showed to be safe for use in rabbits from five weeks of age onwards, including pregnant rabbits, and did not spread from vaccinated rabbits to in-contact controls. Furthermore, protection to RHDV1 and RHDV2 was demonstrated by challenge, while the serological response to MV was similar to that after vaccination with Nobivac Myxo-RHD. Therefore, routine vaccination with Nobivac Myxo-RHD PLUS can prevent the kept rabbit population from these major viral diseases.

Should the 40-year-old practice of releasing virulent myxoma virus to control rabbits (Oryctolagus cuniculus) be continued?

2006 ◽  
Vol 33 (7) ◽  
pp. 549 ◽  
Author(s):  
D. Berman ◽  
P. J. Kerr ◽  
R. Stagg ◽  
B. H. van Leeuwen ◽  
T. Gonzalez
Keyword(s):  
Virulent Strain ◽  
Clinical Signs ◽  
Laboratory Strain ◽  
Myxoma Virus ◽  
South West ◽  
Rabbit Haemorrhagic Disease ◽  
Virulent Virus ◽  
Original Laboratory ◽  
The 1960S ◽  
Haemorrhagic Disease

Release of virulent myxoma virus has been a key component of rabbit-control operations in Queensland, Australia, since the 1960s but its use rests on anecdotal reports. During a routine operation to release virulent myxoma virus we found no evidence to support the continued regular use of the technique in south-west Queensland. Radio-tagged rabbits inoculated with virulent myxoma virus contracted the disease but failed to pass enough virus to other rabbits to spread the disease. Rabbits with clinical signs of myxomatosis that were shot were infected with field strain derived from the original laboratory strain released in 1950 rather than the virulent strain that has been released annually. There was no change in rabbit survival or abundance caused by the release. Nevertheless, the release of virulent virus may be useful against isolated pockets of rabbits mainly because field strains are less likely to be present. Such pockets are more common now that rabbit haemorrhagic disease virus is established in Queensland.

Potential use of myxoma virus and rabbit haemorrhagic disease virus to control feral rabbits in the Kerguelen Archipelago

2004 ◽  
Vol 31 (4) ◽  
pp. 415 ◽  
Author(s):  
B. D. Cooke ◽  
J.-L. Chapuis ◽  
V. Magnet ◽  
A. Lucas ◽  
J. Kovaliski
Keyword(s):  
Disease Virus ◽  
Disease Transmission ◽  
Biological Control Agent ◽  
Myxoma Virus ◽  
European Rabbit ◽  
Rabbit Haemorrhagic Disease Virus ◽  
Rabbit Haemorrhagic Disease ◽  
Haemorrhagic Disease ◽  
Low Prevalence ◽  
Kerguelen Archipelago

Rabbits have caused enormous damage to the vegetation on seven islands in the sub-Antarctic Kerguelen archipelago, including the main island, Grande Terre. Rabbit sera collected during 2001–02 were tested for antibodies against myxoma virus and rabbit haemorrhagic disease virus with a view to considering the wider use of these viruses to control rabbits. The results confirmed work done 15–20 years earlier that suggested that myxoma virus has not spread across all parts of Grande Terre and occurs at low prevalence among rabbits. By contrast, on Ile du Cimetière, where European rabbit fleas were introduced in 1987–88, the prevalence of myxoma antibodies is high and the rabbit population is relatively low, supporting the idea that the fleas are effective vectors of myxoma virus. Consequently, there should be benefits in releasing fleas on Grand Terre to enhance disease transmission. Reactivity of some rabbit sera in RHD-specific ELISAs suggested that a virus similar to RHDV may be present at low prevalence on Grande Terre but most rabbits are likely to be susceptible and this virus could be considered for use as a future biological control agent.

Monitoring of the novel rabbit haemorrhagic disease virus type 2 (GI.2) epidemic in European wild rabbits (Oryctolagus cuniculus) in southern Spain, 2013–2017

2019 ◽  
Vol 237 ◽  
pp. 108361
Author(s):  
L. Camacho-Sillero ◽  
J. Caballero-Gómez ◽  
F. Gómez-Guillamón ◽  
A. Martínez-Padilla ◽  
M. Agüero ◽  
...  
Keyword(s):  
Disease Virus ◽  
Virus Type ◽  
Oryctolagus Cuniculus ◽  
Southern Spain ◽  
The Novel ◽  
Rabbit Haemorrhagic Disease Virus ◽  
Rabbit Haemorrhagic Disease ◽  
Disease Virus Type ◽  
Haemorrhagic Disease

Diet of mammalian predators in braided river beds in the central South Island, New Zealand

2004 ◽  
Vol 31 (6) ◽  
pp. 631 ◽  
Author(s):  
Elaine C. Murphy ◽  
Rachel J. Keedwell ◽  
Kerry P. Brown ◽  
Ian Westbrooke
Keyword(s):  
New Zealand ◽  
Bird Species ◽  
Gut Contents ◽  
Frequency Of Occurrence ◽  
Braided River ◽  
Braided Rivers ◽  
Rabbit Haemorrhagic Disease ◽  
Mammalian Predators ◽  
Mustela Furo ◽  
Haemorrhagic Disease

In New Zealand, five of the six endemic bird species that breed primarily in South Island braided river beds are classed as threatened. A major cause of decline for these species is predation by introduced mammals, and predator-trapping programs are undertaken in the braided rivers of the Mackenzie Basin to protect them. Trapping programs carried out between September 1997 and April 2001 provided the opportunity to investigate predator diet from the gut contents of 375 cats (Felis catus), 371 ferrets (Mustela furo) and 86 stoats (Mustela erminea). As a percentage frequency of occurrence of the main prey items, cat diet consisted of lagomorphs (present in 70% of guts), birds (in 47%), lizards (30%) and invertebrates (36%). Ferret diet consisted of lagomorphs (69%) and birds (28%). Stoat diet consisted of lagomorphs (50%), birds (51%), lizards (21%) and invertebrates (23%). The frequency of occurrence of birds in all three predators was higher in the spring/summer of 1997 – immediately after rabbit haemorrhagic disease (RHD) was introduced – than in any other previous diet study on these braided rivers. This suggests that RHD did lead to increased predation pressure on birds, at least in the short term.

scholarly journals African swine fever virus – the possible role of flies and other insects in virus transmission

2020 ◽  
Vol 64 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Mateusz Fila ◽  
Grzegorz Woźniakowski
Keyword(s):  
African Swine Fever Virus ◽  
Animal Health ◽  
Virus Transmission ◽  
Disease Outbreaks ◽  
African Swine Fever ◽  
Disease Spread ◽  
The Baltic ◽  
Haemorrhagic Disease ◽  
And Control

AbstractAfrican swine fever (ASF) is an acute viral haemorrhagic disease of pigs and wild boars. It presents a serious threat to pig production worldwide, and since 2007, ASF outbreaks have been recorded in the Caucasus, Eastern Europe, and the Baltic States. In 2014, the disease was detected in Poland. ASF is on the list of notifiable diseases of the World Organisation for Animal Health (OIE). Due to the lack of an available vaccine and treatment, the countermeasures against the disease consist in early detection of the virus in the pig population and control of its spread through the elimination of herds affected by disease outbreaks. Knowledge of the potential vectors of the virus and its persistence in the environment is crucial to prevent further disease spread and to understand the new epidemiology for how it compares to the previous experience in Spain gathered in the 1970s and 1980s.

scholarly journals COVID-19 Disease: ORF8 and Surface Glycoprotein Inhibit Heme Metabolism by Binding to Porphyrin

2020 ◽  
Author(s):  
liu wenzhong ◽  
Li hualan
Keyword(s):  
Rna Virus ◽  
Surface Glycoprotein ◽  
The Novel ◽  
Scientific Significance ◽  
Positive Strand Rna Virus ◽  
Novel Coronavirus ◽  
Positive Strand Rna ◽  
Bat Coronavirus ◽  
Anabolic Pathway

<p>The novel coronavirus pneumonia (COVID-19) is an infectious acute respiratory infection caused by the novel coronavirus. The virus is a positive-strand RNA virus with high homology to bat coronavirus. Due to the limits of the existing experimental tools, many protein roles of novel coronavirus including ORF8 are still unclear. Therefore, in the current scene of an emergency epidemic, it is of high scientific significance to predict the biological role of viral proteins through bioinformatics methods. In this study, conserved domain analysis, homology modeling, and molecular docking were used to compare the biological roles of certain proteins of the novel coronavirus. The results showed the ORF8 and surface glycoprotein could bind to the porphyrin, respectively, while orf1ab, ORF10 and ORF3a proteins could coordinately attack heme to dissociate the iron to form the porphyrin. The mechanism seriously interfered with the normal heme anabolic pathway of the human body, being expected to result in human disease. According to the validation analysis of these finds, Chloroquine could prevent orf1ab, ORF3a and ORF10 to attack the heme to form the porphyrin, and inhibit the binding of ORF8 and surface glycoproteins to porphyrins to a certain extent. Therefore, this research is of high value to contemporary biological experiments, disease prevention and clinical treatment.</p>

Australia's War Against Rabbits

2014 ◽  
Author(s):  
Brian Douglas Cooke
Keyword(s):  
Biological Control ◽  
Rna Virus ◽  
Mediterranean Ecosystems ◽  
Emerging Diseases ◽  
Common Interest ◽  
Biological Control Agents ◽  
Virus Structure ◽  
Animal Populations ◽  
Rabbit Haemorrhagic Disease ◽  
Haemorrhagic Disease

The management of wild rabbits is a vexing problem worldwide. In countries such as Australia and New Zealand, wild rabbits are regarded as serious pests to agriculture and the environment, while in many European countries they are considered an important hunting resource, and are a cornerstone species in Mediterranean ecosystems, modifying habitats and supporting important predator populations such as the Iberian lynx. The introduction of two viral diseases, myxomatosis and rabbit haemorrhagic disease, as biological control agents in Australia has been met favourably, yet their spread in southern Europe threatens natural rabbit populations. Despite this, scientists with very different goals still work together with a common interest in understanding rabbit biology and epidemiology. Australia's War Against Rabbits uses rabbit haemorrhagic disease as an important case study in understanding how animal populations adapt to diseases, caused in this case by an RNA virus. Looking at rabbit haemorrhagic disease (RHD) in an ecological framework enables insights into both virus and rabbit biology that are relevant for understanding other emerging diseases of importance to humans. This book provides up-to-date information on recent advances in areas ranging from virus structure and disease mechanics through to the sociological implications of using biological control agents and the benefits to the economy and biodiversity. It is a compelling read for wildlife disease researchers, wildlife managers, rabbit biologists, people working in the public health and education sectors, and landholders and farmers with experience or interest in RHD.

scholarly journals Comparative Analysis of RNA Virome Composition in Rabbits and Associated Ectoparasites

2020 ◽  
Vol 94 (11) ◽  
Author(s):  
Jackie E. Mahar ◽  
Mang Shi ◽  
Robyn N. Hall ◽  
Tanja Strive ◽  
Edward C. Holmes
Keyword(s):  
Comparative Analysis ◽  
Myxoma Virus ◽  
European Rabbit ◽  
Rabbit Hemorrhagic Disease Virus ◽  
Gut Contents ◽  
Mechanical Transmission ◽  
Hemorrhagic Disease ◽  
Vertebrate Species ◽  
Invertebrate Species ◽  
Virus Diversity

ABSTRACT Ectoparasites play an important role in virus transmission among vertebrates. Little, however, is known about the nature of those viruses that pass between invertebrates and vertebrates. In Australia, flies and fleas support the mechanical transmission of two viral biological controls against wild rabbits—rabbit hemorrhagic disease virus (RHDV) and myxoma virus. We compared virome compositions in rabbits and these ectoparasites, sequencing total RNA from multiple tissues and gut contents of wild rabbits, fleas collected from these rabbits, and flies trapped sympatrically. Meta-transcriptomic analyses identified 50 novel viruses from multiple RNA virus families. Rabbits and their ectoparasites were characterized by markedly different viromes, with virus abundance greatest in flies. Although viral contigs from six virus families/groups were found in both rabbits and ectoparasites, they clustered in distinct host-dependent lineages. A novel calicivirus and a picornavirus detected in rabbit cecal content were vertebrate specific; the newly detected calicivirus was distinct from known rabbit caliciviruses, while the picornavirus clustered with sapeloviruses. Several picobirnaviruses were also identified that fell in diverse phylogenetic positions, compatible with the idea that they are associated with bacteria. Further comparative analysis revealed that the remaining viruses found in rabbits, and all those from ectoparasites, were likely associated with invertebrates, plants, and coinfecting endosymbionts. While no full genomes of vertebrate-associated viruses were detected in ectoparasites, small numbers of reads from rabbit astrovirus, RHDV, and other lagoviruses were present in flies. This supports a role for flies in the mechanical transmission of RHDV, while their involvement in astrovirus transmission merits additional exploration. IMPORTANCE Ectoparasites play an important role in the transmission of many vertebrate-infecting viruses, including Zika and dengue viruses. Although it is becoming increasingly clear that invertebrate species harbor substantial virus diversity, it is unclear how many of the viruses carried by invertebrates have the potential to infect vertebrate species. We used the European rabbit (Oryctolagus cuniculus) as a model species to compare virome compositions in a vertebrate host and known associated ectoparasite mechanical vectors, in this case, fleas and blowflies. In particular, we aimed to infer the extent of viral transfer between these distinct types of host. Our analysis revealed that despite extensive viral diversity in both rabbits and associated ectoparasites, and the close interaction of these vertebrate and invertebrate species, biological viral transmission from ectoparasites to vertebrate species is rare. We did, however, find evidence to support the idea of a role of blowflies in transmitting viruses without active replication in the insect.

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