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European Journal of Clinical... Jul 2019Clostridium difficile (C. difficile) is a Gram-positive, spore-forming, anaerobic bacillus, which is widely distributed in the intestinal tract of humans and animals and... (Review)
Review
Clostridium difficile (C. difficile) is a Gram-positive, spore-forming, anaerobic bacillus, which is widely distributed in the intestinal tract of humans and animals and in the environment. In the last decade, the frequency and severity of C. difficile infection has been increasing worldwide to become one of the most common hospital-acquired infections. Transmission of this pathogen occurs by the fecal-oral route and the most important risk factors include antibiotic therapy, old age, and hospital or nursing home stay. The clinical picture is diverse and ranges from asymptomatic carrier status, through various degrees of diarrhea, to the most severe, life threatening colitis resulting with death. Diagnosis is based on direct detection of C. difficile toxins in feces, most commonly with the use of EIA assay, but no single test is suitable as a stand-alone test confirming CDI. Antibiotics of choice are vancomycin, fidaxomicin, and metronidazole, though metronidazole is considered as inferior. The goal of this review is to update physicians on current scientific knowledge of C. difficile infection, focusing also on fecal microbiota transplantation which is a promising therapy.
Topics: Anti-Bacterial Agents; Clostridioides difficile; Clostridium Infections; Colitis; Cross Infection; Diarrhea; Disease Reservoirs; Fecal Microbiota Transplantation; Feces; Humans; Risk Factors; Virulence
PubMed: 30945014
DOI: 10.1007/s10096-019-03539-6 -
Rhode Island Medical Journal (2013) Aug 2020Rabies is an acute encephalitis that is caused by rabies virus (RABV) infection, which belongs to the Rhabdoviridae family of viruses. It causes about 59,000 human... (Review)
Review
Rabies is an acute encephalitis that is caused by rabies virus (RABV) infection, which belongs to the Rhabdoviridae family of viruses. It causes about 59,000 human deaths per year (although this number may be under-reported) and is generally fatal, once signs and symptoms begin to appear. Rabies is still very prevalent and under- reported, particularly in low to middle-income countries such as Asia and Africa, where there is lack of access to healthcare and domestic dogs are not widely vaccinated. Although not commonplace in the USA, rabies is mostly transmitted by wild animals such as bats, raccoons, skunks and foxes. Domesticated cats and dogs are also at risk of acquiring rabies, if they have not been vaccinated. Larger carnivores, such as coyotes, bobcats, mountain lions, wolves, bears, woodchucks, and beavers, should also be considered rabid (unless proven otherwise) if they are involved in an unprovoked attack on a person. The rabies vaccine can prevent 99% of deaths if administered promptly after exposure. There are two main vaccination strategies for rabies prevention: pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP). This article reviews background and epidemiology of rabies and current guidelines for rabies PrEP and PEP regimens for the United States.
Topics: Animals; Animals, Domestic; Animals, Wild; Centers for Disease Control and Prevention, U.S.; Disease Reservoirs; Humans; Population Surveillance; Rabies; Rabies Vaccines; United States; Vaccination; Zoonoses
PubMed: 32752569
DOI: No ID Found -
Emerging Infectious Diseases Dec 2019Dogs are the main reservoir of Leishmania infantum and in some countries have been regularly culled as part of government policy to control visceral leishmaniasis. At...
Dogs are the main reservoir of Leishmania infantum and in some countries have been regularly culled as part of government policy to control visceral leishmaniasis. At the 13th Symposium of the Companion Vector-Borne Diseases World Forum in Windsor, UK, March 19-22, 2018, we consolidated a consensus statement regarding the usefulness of dog culling as a means of controlling visceral leishmaniasis. The statement highlighted the futility of culling infected dogs, whether healthy or sick, as a measure to control the domestic reservoir of L. infantum and reduce the risk for visceral leishmaniasis.
Topics: Animals; Disease Reservoirs; Dog Diseases; Dogs; Leishmaniasis; Leishmaniasis, Visceral
PubMed: 31742505
DOI: 10.3201/eid2512.190164 -
Current Opinion in Virology Oct 2020Influenza D is the only type of influenza virus that mainly affects cattle with frequent spillover to other species. Since the initial description of influenza D virus... (Review)
Review
Influenza D is the only type of influenza virus that mainly affects cattle with frequent spillover to other species. Since the initial description of influenza D virus (IDV) in 2011, the virus has been found to circulate among cattle and swine populations worldwide. Research conducted during the past several years has led to an increased understanding of this novel influenza virus with bovines as a reservoir. In this review, we describe the current knowledge of epidemiology and host range of IDV followed by discussion of infection biology and animal model development for IDV. Finally, we review progress towards understanding of the pathogenesis and host response of IDV as well as developing preventive vaccines for IDV.
Topics: Animals; Antibodies, Viral; Cattle; Disease Models, Animal; Disease Reservoirs; Genome, Viral; Host Specificity; Host-Pathogen Interactions; Mice; Orthomyxoviridae Infections; Respiratory Tract Infections; Swine; Thogotovirus; Virus Replication
PubMed: 32932215
DOI: 10.1016/j.coviro.2020.08.004 -
Retrovirology Aug 2021HIV-1 persists in infected individuals despite years of antiretroviral therapy (ART), due to the formation of a stable and long-lived latent viral reservoir. Early ART... (Review)
Review
HIV-1 persists in infected individuals despite years of antiretroviral therapy (ART), due to the formation of a stable and long-lived latent viral reservoir. Early ART can reduce the latent reservoir and is associated with post-treatment control in people living with HIV (PLWH). However, even in post-treatment controllers, ART cessation after a period of time inevitably results in rebound of plasma viraemia, thus lifelong treatment for viral suppression is indicated. Due to the difficulties of sustained life-long treatment in the millions of PLWH worldwide, a cure is undeniably necessary. This requires an in-depth understanding of reservoir formation and dynamics. Differences exist in treatment guidelines and accessibility to treatment as well as social stigma between low- and-middle income countries (LMICs) and high-income countries. In addition, demographic differences exist in PLWH from different geographical regions such as infecting viral subtype and host genetics, which can contribute to differences in the viral reservoir between different populations. Here, we review topics relevant to HIV-1 cure research in LMICs, with a focus on sub-Saharan Africa, the region of the world bearing the greatest burden of HIV-1. We present a summary of ART in LMICs, highlighting challenges that may be experienced in implementing a HIV-1 cure therapeutic. Furthermore, we discuss current research on the HIV-1 latent reservoir in different populations, highlighting research in LMIC and gaps in the research that may facilitate a global cure. Finally, we discuss current experimental cure strategies in the context of their potential application in LMICs.
Topics: Africa South of the Sahara; Antiretroviral Therapy, Highly Active; Cost of Illness; Developing Countries; Disease Reservoirs; HIV Infections; HIV-1; Humans; Virus Latency
PubMed: 34344423
DOI: 10.1186/s12977-021-00565-1 -
Current Opinion in Virology Feb 2022The emergence of zoonotic viral diseases in humans commonly reflects exposure to mammalian wildlife. Bats (order Chiroptera) are arguably the most important mammalian... (Review)
Review
The emergence of zoonotic viral diseases in humans commonly reflects exposure to mammalian wildlife. Bats (order Chiroptera) are arguably the most important mammalian reservoir for zoonotic viruses, with notable examples including Severe Acute Respiratory Syndrome coronaviruses 1 and 2, Middle East Respiratory Syndrome coronavirus, henipaviruses and lyssaviruses. Herein, we outline our current knowledge on the diversity of bat viromes, particularly through the lens of metagenomic next-generation sequencing and in the context of disease emergence. A key conclusion is that although bats harbour abundant virus diversity, the vast majority of bat viruses have not emerged to cause disease in new hosts such that bats are better regarded as critical but endangered components of global ecosystems.
Topics: Animals; Chiroptera; Disease Reservoirs; Ecosystem; Humans; Middle East Respiratory Syndrome Coronavirus; Phylogeny; Virome; Zoonoses
PubMed: 34954661
DOI: 10.1016/j.coviro.2021.12.008 -
Vaccine Feb 2020The environmental reservoir of Vibrio cholerae, the causative agent of cholera, has been a topic of scientific investigation ever since the discovery of the bacterium... (Review)
Review
The environmental reservoir of Vibrio cholerae, the causative agent of cholera, has been a topic of scientific investigation ever since the discovery of the bacterium itself. While the bacteria can be isolated from both clinical and environmental sources during epidemics, it evades isolation by conventional culture techniques during the period between successive epidemics. The problem is identifying the location and mode of survival and multiplication of V. cholerae during this inter-epidemic period. This information is crucial not only for epidemiological reasons, but also because the seasonality of cholera epidemics is plausibly mediated by the climate-regulated activity of the reservoir. This article focuses on the epidemiological importance of the environmental reservoir of V. cholerae, considering several investigations made on different types of aquatic fauna (zooplanktons, crustaceans, etc.) and flora (macrophytes and microphytes). After evaluating different lines of evidence, we make the case that certain species of cyanobacteria (Anabaena variabilis, Microcystis aeruginosa) can act as inter-epidemic reservoirs of V. cholerae. Physiological and functional aspects of this association are also discussed. We then present a hypothesis, expanding upon a previously published conceptual model, of how the climate-regulated seasonality of cholera epidemics is mediated by the effect of climatic factors on algal bloom and other local abiotic variables in the water, using Bangladesh as a model. Finally, another aspect of the climate-dependence of disease patterns is briefly explored: large-scale environmental signatures associated with cholera, and recent modelling efforts to predict cholera outbreaks based on coastal phytoplankton. The review, therefore, serves not only as a study of the identity of the inter-epidemic reservoir of V. cholerae, but also explores different ways in which the reservoir and the pathogen behaviour is affected by the climate, and the possible consequences it may have on disease pattern.
Topics: Bangladesh; Cholera; Climate; Disease Reservoirs; Epidemics; Eutrophication; Humans; Phytoplankton; Seasons; Vibrio cholerae
PubMed: 31285087
DOI: 10.1016/j.vaccine.2019.06.033 -
Translational Research : the Journal of... Sep 2020Despite the success of anti-retroviral therapy (ART) in transforming HIV into a manageable disease, it has become evident that long-term ART will not eliminate the HIV... (Review)
Review
Despite the success of anti-retroviral therapy (ART) in transforming HIV into a manageable disease, it has become evident that long-term ART will not eliminate the HIV reservoir and cure the infection. Alternative strategies to eradicate HIV infection, or at least induce a state of viral control and drug-free remission are therefore needed. Therapeutic vaccination aims to induce or enhance immunity to alter the course of a disease. In this review we provide an overview of the current state of therapeutic HIV vaccine research and summarize the obstacles that the field faces while highlighting potential ways forward for a strategy to cure HIV infection.
Topics: AIDS Vaccines; Cytotoxicity, Immunologic; Disease Reservoirs; HIV Infections; Humans; T-Lymphocytes, Cytotoxic
PubMed: 32438074
DOI: 10.1016/j.trsl.2020.04.008 -
International Journal of Biological... 2020Mutation and adaptation have driven the co-evolution of coronaviruses (CoVs) and their hosts, including human beings, for thousands of years. Before 2003, two human CoVs... (Review)
Review
Mutation and adaptation have driven the co-evolution of coronaviruses (CoVs) and their hosts, including human beings, for thousands of years. Before 2003, two human CoVs (HCoVs) were known to cause mild illness, such as common cold. The outbreaks of severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS) have flipped the coin to reveal how devastating and life-threatening an HCoV infection could be. The emergence of SARS-CoV-2 in central China at the end of 2019 has thrusted CoVs into the spotlight again and surprised us with its high transmissibility but reduced pathogenicity compared to its sister SARS-CoV. HCoV infection is a zoonosis and understanding the zoonotic origins of HCoVs would serve us well. Most HCoVs originated from bats where they are non-pathogenic. The intermediate reservoir hosts of some HCoVs are also known. Identifying the animal hosts has direct implications in the prevention of human diseases. Investigating CoV-host interactions in animals might also derive important insight on CoV pathogenesis in humans. In this review, we present an overview of the existing knowledge about the seven HCoVs, with a focus on the history of their discovery as well as their zoonotic origins and interspecies transmission. Importantly, we compare and contrast the different HCoVs from a perspective of virus evolution and genome recombination. The current CoV disease 2019 (COVID-19) epidemic is discussed in this context. In addition, the requirements for successful host switches and the implications of virus evolution on disease severity are also highlighted.
Topics: Animals; Betacoronavirus; COVID-19; China; Chiroptera; Coronavirus; Coronavirus Infections; Disease Reservoirs; Evolution, Molecular; Host-Pathogen Interactions; Humans; Pandemics; Pneumonia, Viral; Rodentia; Severe acute respiratory syndrome-related coronavirus; SARS-CoV-2; Severe Acute Respiratory Syndrome; Zoonoses
PubMed: 32226286
DOI: 10.7150/ijbs.45472 -
Frontiers in Immunology 2020In recent years, viruses similar to those that cause serious disease in humans and other mammals have been detected in apparently healthy bats. These include... (Review)
Review
In recent years, viruses similar to those that cause serious disease in humans and other mammals have been detected in apparently healthy bats. These include filoviruses, paramyxoviruses, and coronaviruses that cause severe diseases such as Ebola virus disease, Marburg haemorrhagic fever and severe acute respiratory syndrome (SARS) in humans. The evolution of flight in bats seem to have selected for a unique set of antiviral immune responses that control virus propagation, while limiting self-damaging inflammatory responses. Here, we summarize our current understanding of antiviral immune responses in bats and discuss their ability to co-exist with emerging viruses that cause serious disease in other mammals. We highlight how this knowledge may help us to predict viral spillovers into new hosts and discuss future directions for the field.
Topics: Adaptive Immunity; Animals; Chiroptera; DNA Viruses; Disease Reservoirs; Evolution, Molecular; Host Adaptation; Immune System; Immunity, Innate; Interferons; RNA Viruses; Viral Zoonoses
PubMed: 32117225
DOI: 10.3389/fimmu.2020.00026