Biodegradable Polyester Nanoparticle Vaccines Deliver Self-Amplifying mRNA in Mice at Low Doses

Delivery of self-amplifying mRNA (SAM) has high potential for infectious disease vaccination due to its self-adjuvanting and dose-sparing properties. Yet a challenge is the susceptibility of SAM to degradation and the need for SAM to reach the cytosol fully intact to enable self-amplification. Lipid nanoparticles are successfully deployed at incredible speed for mRNA vaccination, but aspects such as cold storage, manufacturing, efficiency of delivery, and the therapeutic window can benefit from further improvement. To investigate alternatives to lipid nanoparticles, a class of >200 biodegradable end-capped lipophilic poly(beta-amino ester)s (PBAEs) that enable efficient delivery of SAM in vitro and in vivo as assessed by measuring expression of SAM encoding reporter proteins is developed. The ability of these polymers to deliver SAM intramuscularly in mice is evaluated, and a polymer-based formulation that yields up to 37-fold higher intramuscular (IM) expression of SAM compared to injected naked SAM is identified. Using the same nanoparticle formulation to deliver a SAM encoding rabies virus glycoprotein, the vaccine elicits superior immunogenicity compared to naked SAM delivery, leading to seroconversion in mice at low RNA injection doses. These biodegradable nanomaterials may be useful in the development of next-generation RNA vaccines for infectious diseases.Copyright © 2023 The Authors. Advanced Therapeutics published by Wiley-VCH GmbH.

NIH restarts halted bat virus grant

In January, a federal audit found that EcoHealth had misreported nearly $90,000 in expenses for several grants dating to 2014 and that NIH had erred by not justifying its termination (later changed to a suspension) of the 2019 grant. Three years after then-President Donald Trump pressured the U.S. National Institutes of Health (NIH) to shut down a research grant to a group studying how bat coronaviruses jump to people, the agency has restarted the award. [Extracted from the article] Copyright of Science is the property of American Association for the Advancement of Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Infectious disease Roundup 2022

This paper describes the epidemiology, prevalence, transmission, prevention and control of some infectious diseases in companion animals, livestock, wild animals and humans in Ontario, Canada, in 2022, including SARS-CoV-2;Echinococcus multilocularis, Leishmania spp. and SARS-CoV-2;antimicrobial stewardship resources;2 cases of rabid dogs imported from Iran (July 2021 and January 2022);prevalence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriacea, Dirofilaria immitis, Brucella canis, canine parainfluenza and adeno- and herpes viruses in dogs recently imported from Asia;Paragonimus kellicotti lung flukes and Streptococcus equi subsp. zooepidemicus in dogs;African swine fever in pet pigs, backyard pigs and wild pigs and blastomycosis in dogs and humans.

Prospect of Vaccinia virus vector vaccine for wildlife

Against a pandemic of emerged infectious disease, COVID-19, new generation vaccines based on nucleic acids or recombinant viruses, which had not been used as vaccines in humans, have been inoculated and shown to be successful. They are, however, heat-labile and need a cold-chain including deep-freezers for storage and transportation. Vaccinia virus (VAC) vector vaccine (VACV) is a pioneer of new generation of vaccines constructed by using molecular biological technology. VACV, which has contributed to eradication of smallpox, has excellent characteristics of vaccinia virus such as a high heat-stability and long-lasting immunological effects. It is possible to distinguish the immunological responses of vaccination from those of natural infections. We started our developmental researches 35 years ago, using attenuated VAC strains established in Japan. In this article, we first describe the early researches of VACVs;development of two VACVs for Bovine leukemia virus and Rinderpest morbillivirus antigens and their protective immunity in large mammals, sheep and cows. Second, application of VACV is described;Rabies-VACV, which has already been licensed, used in the field in Europe and USA, and resulted in a prominent decrease of rabies. Then, current status of VACV research is described;non-replicating VACVs in mammalian cells have been developed as new-generation and ultimately-safe vaccines. We discuss the possibility of future application of VACV for wildlife.

Transferrin Receptor Protein 1 Cooperates with mGluR2 To Mediate the Internalization of Rabies Virus and SARS-CoV-2.

Identification of bona fide functional receptors and elucidation of the mechanism of receptor-mediated virus entry are important to reveal targets for developing therapeutics against rabies virus (RABV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Our previous studies suggest that metabotropic glutamate receptor subtype 2 (mGluR2) functions as an entry receptor for RABV in vitro, and is an important internalization factor for SARS-CoV-2 in vitro and in vivo. Here, we demonstrate that mGluR2 facilitates RABV internalization in vitro and infection in vivo. We found that transferrin receptor 1 (TfR1) interacts with mGluR2 and internalizes with mGluR2 and RABV in the same clathrin-coated pit. Knockdown of TfR1 blocks agonist-triggered internalization of mGluR2. Importantly, TfR1 also interacts with the SARS-CoV-2 spike protein and is important for SARS-CoV-2 internalization. Our findings identify a novel axis (mGluR2-TfR1 axis) used by RABV and SARS-CoV-2 for entry, and reveal TfR1 as a potential target for therapeutics against RABV and SARS-CoV-2. IMPORTANCE We previously found that metabotropic glutamate receptor subtype 2 (mGluR2) is an entry receptor for RABV in vitro, and an important internalization factor for SARS-CoV-2 in vitro and in vivo. However, whether mGluR2 is required for RABV infection in vivo was unknown. In addition, how mGluR2 mediates the internalization of RABV and SARS-CoV-2 needed to be resolved. Here, we found that mGluR2 gene knockout mice survived a lethal challenge with RABV. To our knowledge, mGluR2 is the first host factor to be definitively shown to play an important role in RABV street virus infection in vivo. We further found that transferrin receptor protein 1 (TfR1) directly interacts and cooperates with mGluR2 to regulate the endocytosis of RABV and SARS-CoV-2. Our study identifies a novel axis (mGluR2-TfR1 axis) used by RABV and SARS-CoV-2 for entry and opens a new door for the development of therapeutics against RABV and SARS-CoV-2.

Treat the "Untreatable" by a Photothermal Agent: Triggering Heat and Immunological Responses for Rabies Virus Inactivation.

Rabies is a fatal neurological zoonotic disease caused by the rabies virus (RABV), and the approved post-exposure prophylaxis (PEP) procedure remains unavailable in areas with inadequate medical systems. Although strategies have been proposed for PEP and postinfection treatment (PIT), because of the complexity of the treatment procedures and the limited curative outcome, developing an effective treatment strategy remains a holy grail in rabies research. Herein, a facile approach is proposed involving photothermal therapy (PTT) and photothermally triggered immunological effects to realize effective PEP and PIT simultaneously. The designed photothermal agent (N+ TT-mCB nanoparticles) featured positively charged functional groups and high photo-to-heat efficiency, which are favorable for virus targeting and inactivation. The level of the virus at the site of infection in mice is significantly decreased upon treatment with orthotopic PTT, and the transfer of the virus to the brain is significantly inhibited. Furthermore, the survival ratio of the mice three days postinfection is increased by intracranial injection of N+ TT-mCB and laser irradiation. Overall, this work provides a platform for the effective treatment of RABV and opens a new avenue for future antiviral studies.

The Prevalence of Viral Pathogens among Bats in Kazakhstan.

Bats carry thousands of viruses from 28 different families. To determine the presence of various pathogens in bat populations in Kazakhstan, 1149 samples (393 oropharyngeal swabs, 349 brain samples, 407 guano) were collected. The samples were collected from four species of bats (Vespertilio murinus, Nyctalus noctula, Myotis blythii, Eptesicus serotinus) in nine regions. The Coronavirus RNA was found in 38 (4.75%) samples, and the rabies virus in 27 (7.74%) samples from bats. Coronaviruses and the rabies virus were found in bats in six out of nine studied areas. The RNAs of SARS-CoV-2, MERS, TBE, CCHF, WNF, influenza A viruses were not detected in the bat samples. The phylogeny of the RdRp gene of 12 samples made it possible to classify them as alphacoronaviruses and divide them into two groups. The main group (n = 11) was closely related to bat coronaviruses from Ghana, Zimbabwe and Kenya. The second group (n = 1) was closely related to viruses previously isolated in the south of Kazakhstan. The phylogeny of the N gene sequence from a bat from west Kazakhstan revealed its close relationship with isolates from the Cosmopolitan group of rabies viruses (Central Asia). These results highlight the need for a continuous monitoring of volatile populations to improve the surveillance and detection of infectious diseases.

Plant-Derived Recombinant Vaccines against Zoonotic Viruses.

Emerging and re-emerging zoonotic diseases cause serious illness with billions of cases, and millions of deaths. The most effective way to restrict the spread of zoonotic viruses among humans and animals and prevent disease is vaccination. Recombinant proteins produced in plants offer an alternative approach for the development of safe, effective, inexpensive candidate vaccines. Current strategies are focused on the production of highly immunogenic structural proteins, which mimic the organizations of the native virion but lack the viral genetic material. These include chimeric viral peptides, subunit virus proteins, and virus-like particles (VLPs). The latter, with their ability to self-assemble and thus resemble the form of virus particles, are gaining traction among plant-based candidate vaccines against many infectious diseases. In this review, we summarized the main zoonotic diseases and followed the progress in using plant expression systems for the production of recombinant proteins and VLPs used in the development of plant-based vaccines against zoonotic viruses.

Characterization of the Immune Response of MERS-CoV Vaccine Candidates Derived from Two Different Vectors in Mice.

Middle East respiratory syndrome (MERS) is an acute, high-mortality-rate, severe infectious disease caused by an emerging MERS coronavirus (MERS-CoV) that causes severe respiratory diseases. The continuous spread and great pandemic potential of MERS-CoV make it necessarily important to develop effective vaccines. We previously demonstrated that the application of Gram-positive enhancer matrix (GEM) particles as a bacterial vector displaying the MERS-CoV receptor-binding domain (RBD) is a very promising MERS vaccine candidate that is capable of producing potential neutralization antibodies. We have also used the rabies virus (RV) as a viral vector to design a recombinant vaccine by expressing the MERS-CoV S1 (spike) protein on the surface of the RV. In this study, we compared the immunological efficacy of the vaccine candidates in BALB/c mice in terms of the levels of humoral and cellular immune responses. The results show that the rabies virus vector-based vaccine can induce remarkably earlier antibody response and higher levels of cellular immunity than the GEM particles vector. However, the GEM particles vector-based vaccine candidate can induce remarkably higher antibody response, even at a very low dose of 1 µg. These results indicate that vaccines constructed using different vaccine vector platforms for the same pathogen have different rates and trends in humoral and cellular immune responses in the same animal model. This discovery not only provides more alternative vaccine development platforms for MERS-CoV vaccine development, but also provides a theoretical basis for our future selection of vaccine vector platforms for other specific pathogens.

Infectious disease management in animal shelters

This second edition contains 24 new and updated chapters on aetiology, epidemiology, prevalence, pathogenesis, clinical signs, treatment, prevention and control of infectious diseases in cats, dogs and exotic small companion mammals in animal shelters. These include an introduction to infectious disease management in animal shelters, wellness, data surveillance, diagnostic testing, necropsy techniques, outbreak management, pharmacology, sanitation, canine and feline vaccinations and immunology, canine infectious respiratory disease, canine distemper virus, canine influenza, feline infectious respiratory disease, canine parvovirus and other canine enteropathogens, feline panleukopenia, feline coronavirus and feline infectious peritonitis, internal parasites, heartworm disease, external parasites, dermatophytoses, zoonoses, rabies, feline leukaemia and feline immunodeficiency viruses and conditions in exotic companion mammals (ferrets, rabbits, guineapigs and rodents). It is intended for shelter veterinarians, managers and workers.

Bacterial, fungal and viral zoonoses of pets

Today, pets are the source of numerous infectious diseases that can be transmitted to humans, as a result of their increasingly frequent contact. The most important viruses with zoonotic potential include rabies and influenza viruses as well as rotaviruses and noroviruses. However, the importance of individual viruses varies depending on the climate and infectious disease control systems in certain countries. Dogs, cats, and other increasingly popular types of pets can transmit bacterial zoonotic agents to humans in various ways. In addition to known pathogens such as the bacteria causing leptospirosis, salmonellosis, campylobacteriosis, or brucellosis, the bacteria Pasteurella multocida and Bartonella henselae transmitted by bites or scratches are also significant in human pathology. There has been a significant increase in the prevalence of methicillin-resistant strains of Staphylococcus aureus in isolates originating from pets and the transmission of these strains between humans and animals requires special attention. Furthermore, fungi causing diseases such as sporotrichosis or dermatophytosis are linked to long-term and persistent infections in humans. The epidemiological situation caused by SARS-CoV-2, and the assumption of an interspecies jump of this virus from animals to humans, including its documented presence in domestic cats, dogs, tigers, and martens, have raised the question of the possibility of virus transmission from pets to humans. However, the current pandemic is caused exclusively by SARS-CoV-2 transmission in the human population, and these animals are not a source of infection for humans. A significant number of zoonoses originating from pets is a threat to public health, thus requiring the "One Health" approach through close cooperation between human and veterinary medicine to develop and implement effective health measures for both humans and animals. As part of responsible ownership, pet owners must be informed by veterinarians about measures to prevent infectious diseases and certain risks that are related to keeping certain species of animals.

Clofazimine derivatives as potent broad-spectrum antiviral agents with dual-target mechanism.

Thirty-two clofazimine derivatives, of which twenty-two were new, were synthesized and evaluated for their antiviral effects against both rabies virus and pseudo-typed SARS-CoV-2, taking clofazimine (1) as the lead. Among them, compound 15f bearing 4-methoxy-2-pyridyl at the N5-position showed superior or comparable antiviral activities to lead 1, with the EC50 values of 1.45 µM and 14.6 µM and the SI values of 223 and 6.1, respectively. Compound 15f inhibited rabies and SARS-CoV-2 by targeting G or S protein to block membrane fusion, as well as binding to L protein or nsp13 to inhibit intracellular biosynthesis respectively, and thus synergistically exerted a broad-spectrum antiviral effect. The results provided useful scientific data for the development of clofazimine derivatives into a new class of broad-spectrum antiviral candidates.

Bats as Reservoirs of Viral Zoonoses

In the last few decades, a special interest in viruses hosted by bats arose after links with zoonoses of public health importance emerged. A dramatic increase in documented viral diversity in bats has occurred with an increasing difficulty in interpretation of results and risk assessments. In addition, the risk of spillover directly from bats or through other intermediate hosts is on the rise as human exposure results from habitat encroachment, human population expansion, deforestation and changes in climate and human behavior, such as increased bushmeat consumption, live animal markets, and cave exploration. The link between rabies and bats has been known for decades;however, there are many other viruses that also pose a threat with no prophylactic treatment or prevention measures existing yet. In addition, viruses have different routes of transmission and shedding may be seasonal. Our aim is to summarize what is known about important virus families implicated in zoonotic events with a bat origin. We include a discussion on potential immunological characteristics that allow bats to harbor many of these viruses without showing signs of disease and raise awareness on how to avoid exposure by considering different routes of exposure to infectious agents.

Interferon Inhibition Enhances the Pilot-Scale Production of Rabies Virus in Human Diploid MRC-5 Cells.

Inactivated vaccines based on cell culture are very useful in the prevention and control of many diseases. The most popular strategy for the production of inactivated vaccines is based on monkey-derived Vero cells, which results in high productivity of the virus but has a certain carcinogenic risk due to non-human DNA contamination. Since human diploid cells, such as MRC-5 cells, can produce a safer vaccine, efforts to develop a strategy for inactivated vaccine production using these cells have been investigated using MRC-5 cells. However, most viruses do not replicate efficiently in MRC-5 cells. In this study, we found that rabies virus (RABV) infection activated a robust interferon (IFN)-ß response in MRC-5 cells but almost none in Vero cells, suggesting that the IFN response could be a key limiting factor for virus production. Treatment of the MRC-5 cells with IFN inhibitors increased RABV titers by 10-fold. Additionally, the RABV titer yield was improved five-fold when using IFN receptor 1 (IFNAR1) antibodies. As such, we established a stable IFNAR1-deficient MRC-5 cell line (MRC-5IFNAR1-), which increased RABV production by 6.5-fold compared to normal MRC-5 cells. Furthermore, in a pilot-scale production in 1500 square centimeter spinner flasks, utilization of the MRC-5IFNAR1- cell line or the addition of IFN inhibitors to MRC cells increased RABV production by 10-fold or four-fold, respectively. Thus, we successfully established a human diploid cell-based pilot scale virus production platform via inhibition of IFN response for rabies vaccines, which could also be used for other inactivated virus vaccine production.

EFSA and ECDC publishes EU One Health 2020 zoonoses report

The European Food Safety Authority (EFSA) and the European Centre for Disease Prevention and Control (ECDC) have published the EU One Health 2020 Zoonoses Report. Campylobacteriosis was the most reported zoonosis in the EU in 2020, with 120,946 cases compared to more than 220,000 the previous year. This was followed by salmonellosis, which affected 52,702 people, compared to 88,000 in 2019. The number of reported foodborne outbreaks fell by 47%, with the report acknowledging the impact of the COVID-19 pandemic in the drop in reported zoonotic diseases in humans. The next most commonly reported diseases were yersiniosis, with 5,668 cases, and infections caused by Shiga toxin-producing Escherichia coli, with 4,446 cases. Listeriosis was the fifth most reported zoonosis, mainly affecting people over the age of 64. Listeriosis and West Nile virus (WNV) infections were the diseases with the highest case fatality and hospitalisation rates, with most locally acquired human infections of WNV reported in Greece, Spain and Italy. The report also monitors foodborne outbreaks in the EU, events during which at least two people contract the same illness from the same contaminated food. A total of 3,086 foodborne outbreaks were reported in 2020, with Salmonella remaining the most frequently detected agent, causing around 23% of outbreaks. The most common sources of salmonellosis outbreaks were eggs, egg products and pig meat. The report also includes data on Mycobacterium bovis, Mycobacterium caprae, Brucella, Trichinella, Echinococcus, Toxoplasma gondii, rabies, Q fever and tularaemia.

Anno 2021: Which antivirals for the coming decade?

Despite considerable progress in the development of antiviral drugs, among which anti-immunodeficiency virus (HIV) and anti-hepatitis C virus (HCV) medications can be considered real success stories, many viral infections remain without an effective treatment. This not only applies to infectious outbreaks caused by zoonotic viruses that have recently spilled over into humans such as severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), but also ancient viral diseases that have been brought under control by vaccination such as variola (smallpox), poliomyelitis, measles, and rabies. A largely unsolved problem are endemic respiratory infections due to influenza, respiratory syncytial virus (RSV), and rhinoviruses, whose associated morbidity will likely worsen with increasing air pollution. Furthermore, climate changes will expose industrialized countries to a dangerous resurgence of viral hemorrhagic fevers, which might also become global infections. Herein, we summarize the recent progress that has been made in the search for new antivirals against these different threats that the world population will need to confront with increasing frequency in the next decade.

Bats and viruses: a death-defying friendship.

Bats have a primeval evolutionary origin and have adopted various survival methods. They have played a central role in the emergence of various viral diseases. The sustenance of a plethora of virus species inside them has been an earnest area of study. This review explains how the evolution of viruses in bats has been linked to their metabolic pathways, flight abilities, reproductive abilities and colonization behaviors. The utilization of host immune response by DNA and RNA viruses is a commencement of the understanding of differences in the impact of viral infection in bats from other mammals. Rabies virus and other lyssa viruses have had long documented history as bat viruses. While many others like Ebola virus, Nipah virus, Hantavirus, SARS-CoV, MERS-CoV and other new emerging viruses like Sosuga virus, Menangle and Tioman virus are now being studied extensively for their transmission in new hosts. The ongoing pandemic SARS-CoV-2 virus has also been implicated to be originated from bats. Certain factors have been linked to spillover events while the scope of entitlement of other conditions in the spread of diseases from bats still exists. However, certain physiological and ecological parameters have been linked to specific transmission patterns, and more definite proofs are awaited for establishing these connections.

Emerging and Neglected Viruses of Zoonotic Importance in Croatia.

Several arboviruses have emerged in Croatia in recent years. Tick-borne encephalitis is endemic in continental counties; however, new natural micro-foci have been detected. Two autochthonous dengue cases were reported in 2010. West Nile virus emerged in 2012, followed by emergence of Usutu virus in 2013. Although high seroprevalence rates of Toscana virus have been detected among residents of Croatian littoral, the virus remains neglected, with only a few clinical cases of neuroinvasive infections reported. Lymphocytic choriomeningitis virus is a neglected neuroinvasive rodent-borne virus. So far, there are no reports on human clinical cases; however, the seroprevalence studies indicate the virus presence in the Croatian mainland. Puumala and Dobrava hantaviruses are widely distributing rodent-borne viruses with sporadic and epidemic occurrence. Hepatitis E virus is an emerging food-borne virus in Croatia. After the emergence in 2012, cases were regularly recorded. Seropositivity varies greatly by region and population group. Rotaviruses represent a significant healthcare burden since rotavirus vaccination is not included in the Croatian national immunization program. Additionally, rotaviruses are widely distributed in the Croatian ecosystem. A novel coronavirus, SARS-CoV-2, emerged in February 2020 and spread rapidly throughout the country. This review focuses on emerging and neglected viruses of zoonotic importance detected in Croatia.