Emerging and Miscellaneous Viral Infections

• The infectious diseases described in this chapter are either: (1) diseases of humans or other animals generally transmitted through contact with the secretions or excretions of rodents (hantaviruses, arenaviruses, and encephalomyocarditis virus), swine (hepatitis E virus), monkeys (Ebola virus), or bats (systemic coronaviruses);(2) common diseases of humans where the role of companion animals in transmission has been investigated (enteroviruses, SARS-CoV-2);(3) diseases of significant importance to the agricultural industry (foot-and-mouth disease virus, vesicular exanthema, encephalomyocarditis virus);or (4) significant diseases of potential prey of dogs and cats (rabbit hemorrhagic disease virus). • Clinical illness has not always been confirmed in dogs and cats with these infections, but evidence of seroconversion to these viruses exists. • In some cases, concern has been raised in the possible role of dogs and cats in zoonotic transmission;this has been heightened by the COVID-19 pandemic. • In general, research suggests that dogs and cats do not play a major role in transmission of these viruses, but the potential exists should new viral variants emerge. © 2021 Elsevier Inc. All rights reserved.

Prospects of lassa fever candidate vaccines

Background: Lassa fever is an acute viral haemorrhagic disease caused by the Lassa virus (LASV). It is endemic in West Africa and infects about 300,000 people each year, leading to approximately 5000 deaths annually. The development of the LASV vaccine has been listed as a priority by the World Health Organization since 2018. Considering the accelerated development and availability of vaccines against COVID-19, we set out to assess the prospects of LASV vaccines and the progress made so far. Materials and Methods: We reviewed the progress made on twenty-six vaccine candidates listed by Salami et al. (2019) and searched for new vaccine candidates through Google Scholar, PubMed, and DOAJ from June to July 2021. We searched the articles published in English using keywords that included "vaccine" AND "Lassa fever" OR "Lassa virus" in the title/. Results: Thirty-four candidate vaccines were identified - 26 already listed in the review by Salami et al. and an additional 8, which were developed over the last seven years. 30 vaccines are still in the pre-clinical stage while 4 of them are currently undergoing clinical trials. The most promising candidates in 2019 were vesicular stomatitis virus-vectored vaccine and live-attenuated MV/LASV vaccine;both had progressed to clinical trials. Conclusions: Despite the focus on COVID-19 vaccines since 2020, LASV vaccine is under development and continues to make impressive progress, hence more emphasis should be put into exploring further clinical studies related to the most promising types of vaccines identified.

Summary of global surveillance data of infectious diseases in January 2023

In January 2023, a total of 64 infectious diseases were reported globally, affecting 235 countries and regions. Except for influenza, the top five infectious diseases affecting greatest number of countries and regions were COVID-19 (235), monkeypox (110), dengue fever (31), measles (27) and cholera (15). The top five infectious diseases with highest case fatality rates were Nipah virus disease (62.5%), Ebola virus disease (47.0%), Crimean-Congo haemorrhagic fever (37.5%), Lassa fever (15.1%) and West Nile fever (7.6%). The top five infectious diseases with greatest number of deaths were COVID-19, malaria, cholera, measles and dengue fever. The prevalent infectious diseases in Asia were COVID-19, cholera and dengue fever, the prevalent infectious diseases in Africa were COVID-19, cholera, yellow fever, Lassa fever, malaria and monkeypox, the prevalent infectious diseases in America were COVID-19, cholera, monkeypox, dengue fever and chikungunya fever, the prevalent infectious disease in Europe were COVID-19, monkeypox and invasive group A streptococcus infection.

Summary of global surveillance data of infectious diseases in December 2022

In December 2022, a total of 68 infectious diseases were reported globally, affecting 235 countries and regions. Except for influenza, the top five infectious diseases affecting greatest number of countries and regions were COVID-19 (235), monkeypox (110), dengue fever (28), measles (27) and cholera (14). The top five infectious diseases with highest case fatality rates were Ebola virus disease (47.0%), Rift Valley fever (44.2%), Crimean-Congo haemorrhagic fever (40.0%), Lassa fever (17.6%) and West Nile fever (7.6%). The top five infectious diseases with greatest number of deaths were COVID-19, malaria, cholera, dengue fever and measles. The prevalent infectious diseases in Asia were COVID-19, cholera and dengue fever, the prevalent infectious diseases in Africa were COVID-19, cholera, yellow fever, Lassa fever, monkeypox, malaria and measles, the prevalent infectious diseases in America were COVID-19, cholera, monkeypox, dengue fever and chikungunya fever, the prevalent infectious disease in Europe were COVID-19, monkeypox and invasive group A streptococcus infection.

Enhancing vaccination of key populations: lessons and actions

Vaccination is effective in preventing the increase of disease, especially emerging infectious diseases (EIDs), and it is particularly important for people in close contact with infected sources and susceptible populations who are at increased risk of getting infectious diseases due to behavior, occupation or health. Despite targeted vaccination guidelines, inadequate vaccination of the key populations fails to receive widespread attention, resulting in a high-risk transition of disease from key populations to general populations. Strengthening the vaccination of the susceptible groups can effectively block the spread of pathogens to general populations, and reduce the consumption of medical resources in universal vaccination, which has significant economic value. In this review, we describe the prevalence of EIDs, analyze the experience and lessons of infectious disease vaccination in key populations through several cases, and further explore the causes for the decline in vaccination rates of key populations. According to the trends of EIDs, a plan to strengthen the vaccination of key populations is proposed to effectively prevent the transition of EIDs from key populations to general populations.

Summary of global surveillance data of infectious diseases in may 2022

In May 2022, a total of 66 infectious diseases were reported globally, affecting 233 countries and regions. Except for influenza, the top five infectious diseases affecting greatest number of countries and regions were COVID-19 (233), monkeypox (36), dengue fever (31), measles (24) and cholera (11). The top five infectious diseases with highest case fatality rates were Ebola virus disease (100.0%), Middle East Respiratory Syndrome (34.4%), Crimean-Congo hemorrhagic fever (22.2%), Lassa fever (19.8%) and monkeypox (4.0%). The top five infectious diseases with greatest number of deaths were COVID-19, malaria, cholera, dengue fever and measles. The prevalent infectious diseases in Asia were COVID-19, dengue fever and cholera, the prevalent infectious diseases in Africa were COVID-19, Ebola virus disease, cholera, yellow fever, Lassa fever, malaria and monkeypox, the prevalent infectious diseases in America were COVID-19, dengue fever, chikungunya fever and Zika virus disease, the prevalent infectious disease in Europe were COVID-19, monkeypox and acute hepatitis of unknown aetiology.

Understanding Host-Virus Interactions: Assessment of Innate Immune Responses in Mastomys natalensis Cells after Arenavirus Infection.

Mastomys natalensis is the natural host of various arenaviruses, including the human-pathogenic Lassa virus. Homologous arenaviruses, defined here as those having M. natalensis as a natural host, can establish long-lasting infection in M. natalensis, while these animals rapidly clear arenaviruses having another rodent species as a natural host (heterologous viruses). Little is known about the mechanisms behind the underlying arenavirus-host barriers. The innate immune system, particularly the type I interferon (IFN) response, might play a role. In this study, we developed and validated RT-PCR assays to analyse the expression of M. natalensis interferon-stimulated genes (ISGs). We then used these assays to study if homologous and heterologous viruses induce different IFN responses in M. natalensis cells. Infection experiments were performed with the homologous Lassa and Morogoro viruses and the related but heterologous Mobala virus. Compared to the direct induction with IFN or Poly(I:C), arenaviruses generally induced a weak IFN response. However, the ISG-expression profiles of homologous and heterologous viruses were similar. Our data indicate that, at least in M. natalensis cells, the IFN system is not a major factor in the virus-host barrier for arenaviruses. Our system provides a valuable tool for future in vivo investigation of arenavirus host restrictions at the level of the innate immune response.

Summary of global surveillance data of infectious diseases in March 2022

In March 2022, a total of 63 infectious diseases were reported globally, affecting 230 countries and regions. Except for influenza, the top five infectious diseases affecting greatest number of countries and regions were COVID-19 (230), dengue fever (32), measles (29), chikungunya fever (10) and cholera (9). The top five infectious diseases with highest case fatality rates were Crimean-Congo haemorrhagic fever (33.3%), Rift Valley fever (20.0%), Lassa fever (18.6%), yellow fever (11.3%) and monkeypox (5.5%). The top five infectious diseases with greatest number of deaths were COVID-19, malaria, measles, cholera and Lassa fever. The prevalent infectious diseases in Asia were COVID-19 and dengue fever, the prevalent infectious diseases in Africa were COVID-19, cholera, yellow fever, Lassa fever, malaria, measles and poliomyelitis, the prevalent infectious diseases in America were COVID-19, dengue fever and chikungunya fever, the prevalent infectious disease in Europe was COVID-19.

The Tetraspanin CD81 Is a Host Factor for Chikungunya Virus Replication.

Chikungunya virus (CHIKV) is an arthritogenic reemerging virus replicating in plasma membrane-derived compartments termed "spherules." Here, we identify the human transmembrane protein CD81 as host factor required for CHIKV replication. Ablation of CD81 results in decreased CHIKV permissiveness, while overexpression enhances infection. CD81 is dispensable for virus uptake but critically required for viral genome replication. Likewise, murine CD81 is crucial for CHIKV permissiveness and is expressed in target cells such as dermal fibroblasts, muscle and liver cells. Whereas related alphaviruses, including Ross River virus (RRV), Semliki Forest virus (SFV), Sindbis virus (SINV) and Venezuelan equine encephalitis virus (VEEV), also depend on CD81 for infection, RNA viruses from other families, such as coronaviruses, replicate independently of CD81. Strikingly, the replication-enhancing function of CD81 is linked to cholesterol binding. These results define a mechanism exploited by alphaviruses to hijack the membrane microdomain-modeling protein CD81 for virus replication through interaction with cholesterol. IMPORTANCE In this study, we discover the tetraspanin CD81 as a host factor for the globally emerging chikungunya virus and related alphaviruses. We show that CD81 promotes replication of viral genomes in human and mouse cells, while virus entry into cells is independent of CD81. This provides novel insights into how alphaviruses hijack host proteins to complete their life cycle. Alphaviruses replicate at distinct sites of the plasma membrane, which are enriched in cholesterol. We found that the cholesterol-binding ability of CD81 is important for its function as an alphavirus host factor. This discovery thus broadens our understanding of the alphavirus replication process and the use of host factors to reprogram cells into virus replication factories.

Summary of global surveillance data of infectious diseases in January 2022

In January 2022, a total of 68 infectious diseases were reported globally, affecting 228 countries and regions. Except for influenza, the top five infectious diseases affecting greatest number of countries and regions were corona virus disease 2019 (COVID-19, 228), dengue fever (26), measles (19), cholera (12) and leptospirosis (10). The top five infectious diseases with highest case fatality rates were Rift Valley fever (100.0%), Lassa fever (19.0%), yellow fever (15.5%), plague (7.5%) and West Nile fever (7.1%). The top five infectious diseases with greatest number of deaths were COVID-19, malaria, measles, Lassa fever and cholera. The prevalent infectious diseases in Asia were COVID-19 and dengue fever, the prevalent infectious diseases in Africa were COVID-19, cholera, yellow fever, Lassa fever, malaria and measles, the prevalent infectious diseases in America were COVID-19, dengue fever and chikungunya fever, the prevalent infectious disease in Europe was COVID-19.

Summary of global surveillance data of infectious diseases in December 2021

In December 2021, a total of 64 infectious diseases were reported globally, affecting 228 countries and regions. Except for influenza, the top five infectious diseases affecting greatest number of countries and regions were corona virus disease 2019 (COVID-19, 228), measles (29), dengue fever (28), cholera (12) and chikungunya fever (9). The top five infectious diseases with highest case fatality rates were Ebola virus disease (81.8%), Middle East respiratory syndrome (34.4%), yellow fever (22.0%), Lassa fever (20.0%) and plague (10.8%). The top five infectious diseases with greatest number of deaths were COVID-19, malaria, measles, dengue fever and cholera. The prevalent infectious diseases in Asia were COVID-19 and dengue fever, the prevalent infectious diseases in Africa were COVID-19, cholera, yellow fever, plague, Lassa fever, poliomyelitis, malaria and measles, the prevalent infectious diseases in America were COVID-19, dengue fever, chikungunya fever and Zika virus disease, the prevalent infectious disease in Europe was COVID-19.

Summary of global surveillance data of infectious diseases in November 2021

In November 2021, a total of 65 infectious diseases were reported globally, affecting 226 countries and regions. Except for influenza, the top five infectious diseases affecting greatest number of countries and regions were Corona virus disease 2019 (COVID-19, 226), dengue fever (31), measles (21), poliomyelitis (11) and cholera (10). The top five infectious diseases with highest case fatality rates were Ebola virus disease (81.8%), Lassa fever (18.6%), yellow fever (15.3%), meningitis (7.9%) and plague (7.6%). The top five infectious diseases with greatest number of deaths were COVID-19, malaria, cholera, dengue fever and yellow fever. The prevalent infectious diseases in Asia were COVID-19 and dengue fever, the prevalent infectious diseases in Africa were COVID-19, Ebola virus disease, cholera, yellow fever, Lassa fever, poliomyelitis, malaria and measles, the prevalent infectious diseases in America were COVID-19, dengue fever, chikungunya fever and Zika virus disease, the prevalent infectious disease in Europe were COVID-19 and West Nile fever.

Summary of global surveillance data of infectious diseases in September 2021

In September 2021, a total of 63 infectious diseases were reported globally, affecting 226 countries and regions. Except for influenza, the top five infectious diseases affecting greatest number of countries and regions were Corona virus disease 2019(COVID-19, 226), dengue fever (28), measles (26), West Nile fever (10) and cholera (9). The top five infectious diseases with highest case fatality rates were Nipah virus disease (100.0%), Middle East respiratory syndrome (34.4%), Lassa fever (20.3%), plague (20.0%) and meningitis (15.8%). The top five infectious diseases with greatest number of deaths were COVID-19, malaria, cholera, meningitis and dengue fever. The prevalent infectious diseases in Asia were COVID-19 and dengue fever, the prevalent infectious diseases in Africa were COVID-19, cholera, plague, yellow fever, Lassa fever, poliomyelitis, malaria and measles, the prevalent infectious diseases in America were COVID-19, dengue fever and chikungunya fever, the prevalent infectious disease in Europe were COVID-19 and West Nile fever.

Special Issue: New coronavirus (2019 n-CoV or SARS-CoV-2) and the outbreak of the respiratory illness (COVID-19): part xv. (Special Issue: New coronavirus (2019 n-CoV or SARS-CoV-2) and the outbreak of the respiratory illness (COVID-19): part xv.)

This special issue contains 58 articles that discuss COVID-19 in relation to other diseases. Topics include dengue fever, tuberculosis, Guillain-Barre syndrome, antiretroviral shortage amidst the pandemic, measles, reinfection by 2 genetically distinct SARS-CoV-2 viruses, Lassa fever, molecular biology of SARS-CoV-2 proteins, dermatological manifestation of COVID-19, immunosuppressive therapy in COVID-19-positive patients, rapid antigen tests for detection of COVID-19, among others.

Lassa virus glycoprotein complex review: insights into its unique fusion machinery.

Lassa virus (LASV), an arenavirus endemic to West Africa, causes Lassa fever-a lethal hemorrhagic fever. Entry of LASV into the host cell is mediated by the glycoprotein complex (GPC), which is the only protein located on the viral surface and comprises three subunits: glycoprotein 1 (GP1), glycoprotein 2 (GP2), and a stable signal peptide (SSP). The LASV GPC is a class one viral fusion protein, akin to those found in viruses such as human immunodeficiency virus (HIV), influenza, Ebola virus (EBOV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). These viruses are enveloped and utilize membrane fusion to deliver their genetic material to the host cell. Like other class one fusion proteins, LASV-mediated membrane fusion occurs through an orchestrated sequence of conformational changes in its GPC. The receptor-binding subunit, GP1, first engages with a host cell receptor then undergoes a unique receptor switch upon delivery to the late endosome. The acidic pH and change in receptor result in the dissociation of GP1, exposing the fusion subunit, GP2, such that fusion can occur. These events ultimately lead to the formation of a fusion pore so that the LASV genetic material is released into the host cell. Interestingly, the mature GPC retains its SSP as a third subunit-a feature that is unique to arenaviruses. Additionally, the fusion domain contains two separate fusion peptides, instead of a standard singular fusion peptide. Here, we give a comprehensive review of the LASV GPC components and their unusual features.

High-Throughput Screening of an FDA-Approved Drug Library Identifies Inhibitors against Arenaviruses and SARS-CoV-2.

Arenaviruses are a large family of enveloped negative-strand RNA viruses that include several causative agents of severe hemorrhagic fevers. Currently, there are no FDA-licensed drugs to treat arenavirus infection except for the off-labeled use of ribavirin. Here, we performed antiviral drug screening against the Old World arenavirus lymphocytic choriomeningitis virus (LCMV) using an FDA-approved drug library. Five drug candidates were identified, including mycophenolic acid, benidipine hydrochloride, clofazimine, dabrafenib, and apatinib, for having strong anti-LCMV effects. Further analysis indicated that benidipine hydrochloride inhibited LCMV membrane fusion, and an adaptive mutation on the LCMV glycoprotein D414 site was found to antagonize the anti-LCMV activity of benidipine hydrochloride. Mycophenolic acid inhibited LCMV replication by depleting GTP production. We also found mycophenolic acid, clofazimine, dabrafenib, and apatinib can inhibit the newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Owing to their FDA-approved status, these drug candidates can potentially be used rapidly in the clinical treatment of arenavirus and SARS-CoV-2 infection.

Screening of Eurasian Tundra Reindeer for Viral Sequences by Next-Generation Sequencing.

Reindeer husbandry is essential for the livelihood and culture of indigenous people in the Arctic. Parts of the herding areas are also used as pastures for farm animals, facilitating potential transmission of viruses between species. Following the Covid-19 pandemic, viruses circulating in the wild are receiving increased attention, since they might pose a potential threat to human health. Climate change will influence the prevalence of infectious diseases of both humans and animals. The aim of this study was to detect known and previously unknown viruses in Eurasian tundra reindeer. In total, 623 nasal and 477 rectal swab samples were collected from reindeer herds in Fennoscandia, Iceland, and Eastern Russia during 2016-2019. Next-generation sequencing analysis and BLAST-homology searches indicated the presence of viruses of domesticated and wild animals, such as bovine viral diarrhea virus, bovine papillomavirus, alcephaline herpesvirus 1 and 2, deer mastadenovirus B, bovine rotavirus, and roe deer picobirnavirus. Several viral species previously found in reindeer and some novel species were detected, although the clinical relevance of these viruses in reindeer is largely unknown. These results indicate that it should be possible to find emerging viruses of relevance for both human and animal health using reindeer as a sentinel species.

New viral vectors for infectious diseases and cancer.

Since the discovery in 1796 by Edward Jenner of vaccinia virus as a way to prevent and finally eradicate smallpox, the concept of using a virus to fight another virus has evolved into the current approaches of viral vectored genetic vaccines. In recent years, key improvements to the vaccinia virus leading to a safer version (Modified Vaccinia Ankara, MVA) and the discovery that some viruses can be used as carriers of heterologous genes encoding for pathological antigens of other infectious agents (the concept of 'viral vectors') has spurred a new wave of clinical research potentially providing for a solution for the long sought after vaccines against major diseases such as HIV, TB, RSV and Malaria, or emerging infectious diseases including those caused by filoviruses and coronaviruses. The unique ability of some of these viral vectors to stimulate the cellular arm of the immune response and, most importantly, T lymphocytes with cell killing activity, has also reawakened the interest toward developing therapeutic vaccines against chronic infectious diseases and cancer. To this end, existing vectors such as those based on Adenoviruses have been improved in immunogenicity and efficacy. Along the same line, new vectors that exploit viruses such as Vesicular Stomatitis Virus (VSV), Measles Virus (MV), Lymphocytic choriomeningitis virus (LCMV), cytomegalovirus (CMV), and Herpes Simplex Virus (HSV), have emerged. Furthermore, technological progress toward modifying their genome to render some of these vectors incompetent for replication has increased confidence toward their use in infant and elderly populations. Lastly, their production process being the same for every product has made viral vectored vaccines the technology of choice for rapid development of vaccines against emerging diseases and for 'personalised' cancer vaccines where there is an absolute need to reduce time to the patient from months to weeks or days. Here we review the recent developments in viral vector technologies, focusing on novel vectors based on primate derived Adenoviruses and Poxviruses, Rhabdoviruses, Paramixoviruses, Arenaviruses and Herpesviruses. We describe the rationale for, immunologic mechanisms involved in, and design of viral vectored gene vaccines under development and discuss the potential utility of these novel genetic vaccine approaches in eliciting protection against infectious diseases and cancer.

Lassa Fever: Viral Replication, Disease Pathogenesis, and Host Immune Modulations.

Despite major discoveries made in the last few decades about Lassa fever, there are still many unresolved key issues that hamper the development of effective vaccines and therapies against this deadly disease that is endemic in several West African countries. Some of these issues include the lack of a detailed understanding of the viral and participating host factors in completing the virus life cycle, in mediating disease pathogenesis or protection from disease, and in activating or suppressing host innate and cellular immunity against virus infection, as well as of the animal models required for testing vaccines and therapeutics. This Special Issue is devoted to understanding some of these important issues and to exploring the current status of the research and development in combating Lassa fever.