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Veterinary Parasitology Feb 2018Leishmania infantum is a vector-borne zoonotic disease transmitted by phlebotomine sand flies and dogs are considered the main reservoir of the parasite. Feline... (Review)
Review
Leishmania infantum is a vector-borne zoonotic disease transmitted by phlebotomine sand flies and dogs are considered the main reservoir of the parasite. Feline leishmaniosis (FeL) caused by L. infantum is an emergent feline disease more and more frequently reported in endemic areas. This review summarizes current knowledge focusing similarities and differences with canine leishmaniosis (CanL). Cats are infected by the same Leishmania species than dogs but prevalence of the infection is lower and cases of disease are less frequently reported. Scarce information is available on adaptive immune response of cats naturally exposed to L. infantum infection and mechanisms responsible for susceptibility or resistance of feline hosts. However, about half of clinical cases of FeL are reported in cats with possible impaired immunocompetence. Coinfections or comorbidities are frequently detected in sick cats and they can contribute to a misrepresentation of clinical FeL albeit lesions associated with the presence of the parasite have been detected in skin, lymph nodes, spleen, bone marrow, liver, oral mucosa, stomach, large bowel, kidney, nasal exudate, lung, eye. As for dogs, skin or mucocutaneous lesions are the most common reason for veterinary consultation and finding on physical examination in cats with leishmaniosis. Molecular investigations of Leishmania DNA and anti- Leishmania antibody detection are largely used with the same methodologies for both CanL and FeL, however few information is available about their diagnostic performance in feline hosts. Treatment of cats with clinical FeL is still empirically based and off label by using the most common drugs prescribed to dogs. Life expectancy of cats with clinical FeL is usually good unless concurrent conditions or complications occur and prognosis does not seem significantly influenced by therapy or retroviral coinfection. According to current knowledge, cats can play a role as additional reservoir host of L. infantum and, in a « One Health » perspective, preventative measures should be taken. In conclusion, albeit feline infection and the associated cat disease caused by L. infantum is increasingly reported in endemic areas and have many similarities with CanL, consolidated evidence-based knowledge is not available and we cannot exclude that important differences between dogs and cats exist about transmission, immunopathogenesis and best practice for management and prevention.
Topics: Animals; Antibodies, Protozoan; Cat Diseases; Cats; Disease Reservoirs; Dog Diseases; Dogs; Leishmania infantum; Leishmaniasis, Visceral
PubMed: 29426470
DOI: 10.1016/j.vetpar.2018.01.012 -
Philosophical Transactions of the Royal... Sep 2019Dose is the nexus between exposure and all upstream processes that determine pathogen pressure, and is thereby an important element underlying disease dynamics.... (Review)
Review
Dose is the nexus between exposure and all upstream processes that determine pathogen pressure, and is thereby an important element underlying disease dynamics. Understanding the relationship between dose and disease is particularly important in the context of spillover, where nonlinearities in the dose-response could determine the likelihood of transmission. There is a need to explore dose-response models for directly transmitted and zoonotic pathogens, and how these interactions integrate within-host factors to consider, for example, heterogeneity in host susceptibility and dose-dependent antagonism. Here, we review the dose-response literature and discuss the unique role dose-response models have to play in understanding and predicting spillover events. We present a re-analysis of dose-response experiments for two important zoonotic pathogens (Middle East respiratory syndrome coronavirus and Nipah virus), to exemplify potential difficulties in differentiating between appropriate models with small exposure experiment datasets. We also discuss the data requirements needed for robust selection between dose-response models. We then suggest how these processes could be modelled to gain more realistic predictions of zoonotic transmission outcomes and highlight the exciting opportunities that could arise with increased collaboration between the virology and epidemiology disciplines. This article is part of the theme issue 'Dynamic and integrative approaches to understanding pathogen spillover'.
Topics: Animals; Animals, Wild; Coronavirus Infections; Disease Reservoirs; Environment; Henipavirus Infections; Host-Pathogen Interactions; Humans; Middle East Respiratory Syndrome Coronavirus; Nipah Virus
PubMed: 31401955
DOI: 10.1098/rstb.2019.0016 -
Foodborne Pathogens and Disease Mar 2019Wild boar populations around the world have increased dramatically over past decades. Climate change, generating milder winters with less snow, may affect their spread... (Review)
Review
Wild boar populations around the world have increased dramatically over past decades. Climate change, generating milder winters with less snow, may affect their spread into northern regions. Wild boars can serve as reservoirs for a number of bacteria, viruses, and parasites, which are transmissible to humans and domestic animals through direct interaction with wild boars, through contaminated food or indirectly through contaminated environment. Disease transmission between wild boars, domestic animals, and humans is an increasing threat to human and animal health, especially in areas with high wild boar densities. This article reviews important foodborne zoonoses, including bacterial diseases (brucellosis, salmonellosis, tuberculosis, and yersiniosis), parasitic diseases (toxoplasmosis and trichinellosis), and the viral hepatitis E. The focus is on the prevalence of these diseases and the causative microbes in wild boars. The role of wild boars in transmitting these pathogens to humans and livestock is also briefly discussed.
Topics: Animals; Communicable Diseases; Disease Reservoirs; Humans; Incidence; Prevalence; Sus scrofa; Swine; Swine Diseases; Zoonoses
PubMed: 30481068
DOI: 10.1089/fpd.2018.2512 -
Trends in Parasitology Feb 2021Because most emerging human pathogens originate in mammals, many studies aim to identify host traits that determine the risk of sourcing zoonotic outbreaks. Studies... (Review)
Review
Because most emerging human pathogens originate in mammals, many studies aim to identify host traits that determine the risk of sourcing zoonotic outbreaks. Studies regularly assert that 'fast-lived' mammal species exhibiting greater fecundity and shorter lifespans tend to host more zoonoses; however, the causes of this association remain poorly understood and they cover a range of immune and nonimmune mechanisms. We discuss these drivers in the context of evolutionary ecology and wildlife-human interactions. Ultimately, differentiating these mechanisms will require linking interspecific variation in life history with immunity, pathogen diversity, transmissibility, and zoonotic risk, and critical data gaps currently limit our ability to do so. We highlight sampling and analytical frameworks to address this gap and to better inform zoonotic reservoir prediction.
Topics: Animals; Biodiversity; Biological Evolution; Disease Reservoirs; Host-Parasite Interactions; Human-Animal Interaction; Humans; Longevity; Parasitic Diseases; Risk; Time Factors; Zoonoses
PubMed: 33214097
DOI: 10.1016/j.pt.2020.10.012 -
Journal of Feline Medicine and Surgery Nov 2015Cytauxzoonosis is a life-threatening hematoprotozoal disease with a rapidly progressive clinical course. Once considered a rare disease only relevant to a small... (Review)
Review
PRACTICAL RELEVANCE
Cytauxzoonosis is a life-threatening hematoprotozoal disease with a rapidly progressive clinical course. Once considered a rare disease only relevant to a small geographic area, it is now recognized in more than about a third of the United States. The geographic range seems likely to increase with expansion of the range of the vector tick.
CLINICAL CHALLENGES
Both disease diagnosis and treatment offer challenges. The acute illness is often recognized by characteristic parasitic cellular inclusions, but illness may occur before parasites can be identified, and parasitic inclusions may persist long after illness has resolved. Also, while infection was once considered nearly uniformly fatal, subclinical infections are now recognized. Disease prognosis has improved for many cats through implementation of new therapies, but some pathogens are resistant to these therapies and death from disease is still common. Currently, prevention strategies are limited to ectoparasite control.
GLOBAL IMPORTANCE
Cytauxzoonosis caused by Cytauxzoon felis is limited to the Americas, and is especially problematic in southeastern and south central USA. However, other Cytauxzoon species have been recognized in Europe and Asia.
AUDIENCE
This review is aimed at veterinary practitioners and focuses on the diagnosis and treatment of cytauxzoonosis. Disease management is of crucial importance in endemic regions. Furthermore, the expanding geographic range of infection, and the possibility of parasite identification in chronically infected cats with a travel history, make understanding cytauxzoonosis relevant in non-endemic regions as well.
EVIDENCE BASE
The authors draw on evidence from prospective clinical trials, experimental infections, retrospective clinical studies and case reports, as well as their own personal experience with the diagnosis and treatment of cytauxzoonosis.
Topics: Animal Welfare; Animals; Animals, Domestic; Asia; Cat Diseases; Cats; Disease Reservoirs; Europe; Prospective Studies; Protozoan Infections, Animal; Retrospective Studies; United States; Veterinary Medicine
PubMed: 26486980
DOI: 10.1177/1098612X15610681 -
Proceedings of the National Academy of... Apr 2022SignificanceThe clear need to mitigate zoonotic risk has fueled increased viral discovery in specific reservoir host taxa. We show that a combination of viral and...
SignificanceThe clear need to mitigate zoonotic risk has fueled increased viral discovery in specific reservoir host taxa. We show that a combination of viral and reservoir traits can predict zoonotic virus virulence and transmissibility in humans, supporting the hypothesis that bats harbor exceptionally virulent zoonoses. However, pandemic prevention requires thinking beyond zoonotic capacity, virulence, and transmissibility to consider collective "burden" on human health. For this, viral discovery targeting specific reservoirs may be inefficient as death burden correlates with viral, not reservoir, traits, and depends on context-specific epidemiological dynamics across and beyond the human-animal interface. These findings suggest that longitudinal studies of viral dynamics in reservoir and spillover host populations may offer the most effective strategy for mitigating zoonotic risk.
Topics: Animals; Chiroptera; Disease Reservoirs; Virulence; Viruses; Zoonoses
PubMed: 35349342
DOI: 10.1073/pnas.2113628119 -
Philosophical Transactions of the Royal... Sep 2019The risk of zoonotic spillover from reservoir hosts, such as wildlife or domestic livestock, to people is shaped by the spatial and temporal distribution of infection in... (Review)
Review
The risk of zoonotic spillover from reservoir hosts, such as wildlife or domestic livestock, to people is shaped by the spatial and temporal distribution of infection in reservoir populations. Quantifying these distributions is a key challenge in epidemiology and disease ecology that requires researchers to make trade-offs between the extent and intensity of spatial versus temporal sampling. We discuss sampling methods that strengthen the reliability and validity of inferences about the dynamics of zoonotic pathogens in wildlife hosts. This article is part of the theme issue 'Dynamic and integrative approaches to understanding pathogen spillover'.
Topics: Animals; Animals, Wild; Disease Reservoirs; Epidemiological Monitoring; Population Surveillance; Reproducibility of Results; Zoonoses
PubMed: 31401966
DOI: 10.1098/rstb.2018.0336 -
Advances in Parasitology 2018Although any fish-eating mammals could be potential definitive hosts of Opisthorchis viverrini, only a few, especially cats and dogs, are actually known reservoir hosts... (Review)
Review
Although any fish-eating mammals could be potential definitive hosts of Opisthorchis viverrini, only a few, especially cats and dogs, are actually known reservoir hosts for this parasite. Both animals usually get infected via consuming raw or undercooked contaminated fish, fish dishes or food remains from households. The infected animals sustain parasite egg spread via open environment defecation. Cats are the most important reservoir with higher prevalence rates of O. viverrini infection than dogs in endemic areas. Usually Opisthorchis-infected animals do not exhibit apparent clinical symptoms or specific abnormalities in laboratory examinations. Pathological findings in these animal reservoirs are basically similar to those seen in humans and experimental animals, namely periductal inflammation, biliary hyperplasia and periductal fibrosis. However, O. viverrini-associated cholangiocarcinoma has not yet been reported in the reservoir animals at present. Praziquantel is a treatment of choice not only for humans but also for animal reservoirs. Integrated control of opisthorchiasis in animal reservoirs is based on holistic approaches such as EcoHealth/One Health concepts. In fact integrated control of opisthorchiasis in humans in ecosystem has also proved successful, for example, the Lawa model for opisthorchiasis control in the endemic area of Khon Kaen, Thailand. Other feral and wild animals in endemic areas might also be potential reservoirs, and this requires more investigation. In addition, genetic diversity and evolution of the flukes might also influence zoonotic capability.
Topics: Animals; Disease Reservoirs; Ecosystem; Humans; Opisthorchiasis; Opisthorchis; Praziquantel; Thailand
PubMed: 29907256
DOI: 10.1016/bs.apar.2018.05.003 -
Parasitology Apr 2018Leptospirosis is a zoonotic bacterial disease of global importance. A large spectrum of asymptomatic animal hosts can carry the infection and contribute to the burden of... (Review)
Review
Leptospirosis is a zoonotic bacterial disease of global importance. A large spectrum of asymptomatic animal hosts can carry the infection and contribute to the burden of human disease. Environmental sources of human contamination also point to the importance of a hydrotelluric reservoir. Leptospirosis can be caused by as many as 15 different pathogenic or intermediate Leptospira species. However, classification of these bacteria remains complicated through the use of both serological and genetic classification systems that show poor correlation. With the advent of molecular techniques, DNA-based barcoding offers a conceptual framework that can be used for leptospirosis surveillance as well as source tracking. In this review, we summarize some of the current techniques, highlight significant successes and weaknesses and point to the future opportunities and challenges to successfully establish a widely applicable barcoding scheme for Leptospira.
Topics: Animals; DNA Barcoding, Taxonomic; Disease Reservoirs; Environmental Microbiology; Genotyping Techniques; Humans; Leptospira; Leptospirosis; Phylogeny; Zoonoses
PubMed: 28716157
DOI: 10.1017/S0031182017001147 -
Medical Anthropology May 2023The introduction of the special issue "Disease Reservoirs: Anthropological and Historical Approaches" sets out the origins and trajectories of disease reservoir...
The introduction of the special issue "Disease Reservoirs: Anthropological and Historical Approaches" sets out the origins and trajectories of disease reservoir frameworks. First, it charts the emergence and elaborations of the reservoirs concept within and across early 20th-century colonial contexts, emphasising its configuration within imperial projects that sought to identify, map and control spaces of contagion among humans, animals, and pathogens. Following this, it traces the position the reservoir framework assumed within post-colonial practices and imaginaries of global health, with particular reference to the emerging infectious disease paradigm. The introduction shows that, in contemporary usages, while the concept continues to frame animals, humans and their bodies as containers of previously identified pathogens, it also emphasises the imperative of anticipating as-of-yet unknown diseases, harboured in the bodies of certain animals, through networks and techniques of surveillance. Consequently, the introduction argues that the notion of disease reservoirs remains intimately intertwined with concerns over the classification, organization, and management of peoples, pathogens, animals, and space. Finally, the introduction outlines the seven papers that form this special issue, stressing how they dialogue, complement, and challenge previous historical and anthropological approaches to disease reservoirs, with an eye to opening up new avenues for cross-disciplinary exploration.
Topics: Animals; Humans; One Health; Anthropology, Medical; Disease Reservoirs; Medicine; Communicable Diseases, Emerging
PubMed: 37522963
DOI: 10.1080/01459740.2023.2214950