Showing papers by "An Martel published in 2016"
TL;DR: This article focuses on discussing options for mitigating the threats once disease emergence has occurred in wild amphibian populations, and assesses disease mitigation options critically and embeds them within more comprehensive strategies for the conservation of amphibians, communities and ecosystems.
Abstract: Amphibians across the planet face the threat of population decline and extirpation caused by the disease chytridiomycosis. Despite consensus that the fungal pathogens responsible for the disease are conservation issues, strategies to mitigate their impacts in the natural world are, at best, nascent. Reducing risk associated with the movement of amphibians, non-amphibian vectors and other sources of infection remains the first line of defence and a primary objective when mitigating the threat of disease in wildlife. Amphibian-associated chytridiomycete fungi and chytridiomycosis are already widespread, though, and we therefore focus on discussing options for mitigating the threats once disease emergence has occurred in wild amphibian populations. All strategies have shortcomings that need to be overcome before implementation, including stronger efforts towards understanding and addressing ethical and legal considerations. Even if these issues can be dealt with, all currently available approaches, or those under discussion, are unlikely to yield the desired conservation outcome of disease mitigation. The decision process for establishing mitigation strategies requires integrated thinking that assesses disease mitigation options critically and embeds them within more comprehensive strategies for the conservation of amphibian populations, communities and ecosystems. This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.
121 citations
TL;DR: In this paper, the chytrid fungus Batrachochytrium salamandrivorans at new locations and in urodeles of different species expands the known geographic and host range of the fungus and underpins its imminent threat to biodiversity.
Abstract: Emerging fungal diseases can drive amphibian species to local extinction. During 2010-2016, we examined 1,921 urodeles in 3 European countries. Presence of the chytrid fungus Batrachochytrium salamandrivorans at new locations and in urodeles of different species expands the known geographic and host range of the fungus and underpins its imminent threat to biodiversity.
114 citations
TL;DR: The prevalence of M. gallisepticum in commercial poultry, broilers and wild birds and the nature of the sample, different diagnostic tests were used including the rapid plate agglutination test, enzyme-linked immunosorbent assay (ELISA), polymerase chain reaction and real-time polymerase reaction.
Abstract: Mycoplasma gallisepticum is the most important pathogenic avian Mycoplasma species and causes chronic respiratory disease in poultry. In addition, the prevalence of Mycoplasma synoviae is of increasing concern in several EU member states. We investigated the prevalence of M. gallisepticum in commercial poultry (5220 layers, 1224 broilers and 1020 meat turkeys), 56 racing pigeons and 890 wild birds (Order Anseriformes, Galliformes, Pelecaniformes, Accipitriformes, Gruiformes, Charadriiformes, Columbiformes, Strigiformes, Falconiformes and Passeriformes). Broilers and wild birds were also evaluated for Mycoplasma synoviae. Dependent on the bird lifespan and the nature of the sample, different diagnostic tests were used including the rapid plate agglutination test, enzyme-linked immunosorbent assay (ELISA), polymerase chain reaction and real-time polymerase chain reaction. A low prevalence of M. gallisepticum was found in both layers (0.9%; 95% CI: 0.7-1.2%) and broilers (2.7%; 95% CI: 1.9-3.8%) possibly due to reduced vertical transmission by breeder farms, which are under official surveillance. None of the samples from turkeys or racing pigeons tested positive. In wild birds, we found five birds were positive (1.7%; 95% CI: 0.7-3.9%): one wood pigeon, two grey herons, one mallard and one Eurasian magpie. For M. synoviae a high prevalence was found in broilers (12.9%: 95% CI: 11.1-14.9%). Four samples collected by hunters gave a positive result for M. synoviae (4%: 95% CI: 1.6-9.8%): one carrion crow and three wood pigeons. In addition, 12 house sparrows were found to be positive (3%; 95% CI: 1.7-5.2%). Wild birds probably play a limited role as a reservoir but we cannot exclude a possible impact on transmission of Mycoplasmas.
52 citations
TL;DR: Clustered massive outbreaks involving dead adult specimens and ranavirus genomic identity indicated that one common midwife toad virus (CMTV)-like ranav virus strain is emerging in provinces in the north of the Netherlands, and modelling based on the spatiotemporal pattern of spread showed a high probability that this emerging virus will be detected at new sites.
Abstract: In the four years following the first detection of ranavirus (genus Ranavirus, family Iridoviridae) infection in Dutch wildlife in 2010, amphibian mortality events were investigated nationwide to detect, characterize and map ranaviruses in amphibians over time, and to establish the affected host species and the clinico-pathological presentation of the disease in these hosts. The ultimate goal was to obtain more insight into ranavirus disease emergence and ecological risk. In total 155 dead amphibians from 52 sites were submitted between 2011 and 2014, and examined using histopathology, immunohistochemistry, virus isolation and molecular genetic characterization. Ranavirus-associated amphibian mortality events occurred at 18 sites (35%), initially only in proximity of the 2010 index site. Specimens belonging to approximately half of the native amphibian species were infected, including the threatened Pelobates fuscus (spadefoot toad). Clustered massive outbreaks involving dead adult specimens and ranavirus genomic identity indicated that one common midwife toad virus (CMTV)-like ranavirus strain is emerging in provinces in the north of the Netherlands. Modelling based on the spatiotemporal pattern of spread showed a high probability that this emerging virus will continue to be detected at new sites (the discrete reproductive power of this outbreak is 0.35). Phylogenetically distinct CMTV-like ranaviruses were found in the south of the Netherlands more recently. In addition to showing that CMTV-like ranaviruses threaten wild amphibian populations not only in Spain but also in the Netherlands, the current spread and risk of establishment reiterate that understanding the underlying causes of CMTV-like ranavirus emergence requires international attention.
42 citations
TL;DR: Patterns and complexity underlying global amphibian trade are outlined, highlighting some loopholes that need to be addressed and steps to improve the policy and enforcement framework are suggested.
Abstract: The global amphibian trade is suspected to have brought several species to the brink of extinction, and has led to the spread of amphibian pathogens. Moreover, international trade is not regulated for ~98 % of species. Here we outline patterns and complexity underlying global amphibian trade, highlighting some loopholes that need to be addressed, focusing on the European Union. In spite of being one of the leading amphibian importers, the EU’s current legislation is insufficient to prevent overharvesting of those species in demand or the introduction and/or spread of amphibian pathogens into captive and wild populations. We suggest steps to improve the policy (implementation and enforcement) framework, including (i) an identifier specifically for amphibians in the World Customs Organisation’s harmonised system, (ii) Parties to CITES should strive to include more species in the CITES appendices, and (iii) restriction or suspension of trade of threatened species, restricted-range species, and species protected in their country of origin. Commercial trade should not put survival of amphibian species further at risk.
39 citations
TL;DR: The alpine die-off is the first CMTV outbreak associated with mass mortality in wild amphibians in France and the lesions observed are described and amphibian populations affected by Ranaviruses in Europe are summarized.
Abstract: Pathogenic fungi and viruses cause mortality outbreaks in wild amphibians worldwide. In the summer of 2012, dead tadpoles and adults of the European common frog Rana temporaria were reported in alpine lakes in the southwestern Alps (Mercantour National Park, France). A preliminary investigation using molecular diagnostic techniques identified a Ranavirus as the potential pathogenic agent. Three mortality events were recorded in the park, and samples were collected. The amphibian chytrid fungus Batrachochytrium dendrobatidis was not detected in any of the dead adult and juvenile frogs sampled (n=16) whereas all specimens were positive for a Ranavirus. The genome sequence of this Ranavirus was identical to previously published sequences of the common midwife toad virus (CMTV), a Ranavirus that has been associated with amphibian mortalities throughout Europe. We cultured virus from the organs of the dead common frogs and infecting adult male common frogs collected in another alpine region where no frog mortality had been observed. The experimentally infected frogs suffered 100% mortality (n=10). The alpine die-off is the first CMTV outbreak associated with mass mortality in wild amphibians in France. We describe the lesions observed and summarize amphibian populations affected by Ranaviruses in Europe. In addition, we discuss the ecologic specificities of mountain amphibians that may contribute to increasing their risk of exposure to and transmission of Ranaviruses.
27 citations
TL;DR: The occurrence of weakly hemolytic strains identifiable as B. hyodysenteriae should be taken into account in swine dysentery diagnostics, and the presence of these strains may affect herd Dysentery status, with great impact on a farms trading opportunities.
Abstract: Brachyspira hyodysenteriae is the primary cause of swine dysentery, which is responsible for major economic losses to the pig industry worldwide. The hemolytic activity of 10 B. hyodysenteriae strains isolated from stools of pigs with mild to mucohemorrhagic diarrhea was compared and seven hemolysis associated genes were sequenced. Hemolysis induced by these strains varied from strong to near absent. One weakly hemolytic B. hyodysenteriae strain showed sequence changes in five hemolysis associated genes (tlyA, tlyB, hemolysin III, hemolysin activation protein and hemolysin III channel protein) resulting in amino acid substitutions. The occurrence of weakly hemolytic strains identifiable as B. hyodysenteriae should be taken into account in swine dysentery diagnostics. The presence of these strains may affect herd dysentery status, with great impact on a farms trading opportunities.
27 citations
TL;DR: This report is the first to present broiler hatching eggs as carriers and a potential source of ESBL/AmpC-producing Enterobacteriaceae for broiler chicks.
Abstract: Antimicrobial resistance is recognized as one of the most important global health challenges. Broilers are an important reservoir of antimicrobial resistant bacteria in general and, more particularly, extended-spectrum β-lactamases (ESBL)/AmpC-producing Enterobacteriaceae. Since contamination of 1-day-old chicks is a potential risk factor for the introduction of antimicrobial resistant Enterobacteriaceae in the broiler production chain, the presence of antimicrobial resistant coliform bacteria in broiler hatching eggs was explored in the present study. Samples from 186 hatching eggs, collected from 11 broiler breeder farms, were inoculated on MacConkey agar with or without ceftiofur and investigated for the presence of antimicrobial resistant lactose-positive Enterobacteriaceae, particularly, ESBL/AmpC-producers. Escherichia coli and Enterobacter cloacae were obtained from the eggshells in 10 out of 11 (10/11) sampled farms. The majority of the isolates were recovered from crushed eggshells after external decontamination suggesting that these bacteria are concealed from the disinfectants in the egg shell pores. Antimicrobial resistance testing revealed that approximately 30% of the isolates showed resistance to ampicillin, tetracycline, trimethoprim and sulphonamides, while the majority of isolates were susceptible to amoxicillin-clavulanic acid, nitrofurantoin, aminoglycosides, florfenicol, neomycin and apramycin. Resistance to extended-spectrum cephalosporins was detected in eight Enterobacteriaceae isolates from five different broiler breeder farms. The ESBL phenotype was confirmed by the double disk synergy test and blaSHV-12, blaTEM-52 and blaACT-39 resistance genes were detected by PCR. This report is the first to present broiler hatching eggs as carriers and a potential source of ESBL/AmpC-producing Enterobacteriaceae for broiler chicks.
24 citations
TL;DR: In this paper, the antibacterial potential of organic acids and essential oil components against Brachyspira hyodysenteriae, the causative pathogen of swine dysentery, was evaluated.
Abstract: The antibacterial potential of organic acids and essential oil components against Brachyspira hyodysenteriae, the causative pathogen of swine dysentery, was evaluated. Minimum inhibitory concentrations (MIC) of 15 compounds were determined at pH 7.2 and pH 6.0, using a broth microdilution assay. In addition, possible synergism was determined. MIC values for the three tested strains were similar. For organic acids, MIC values at pH 6.0 were lower than at pH 7.2. B. hyodysenteriae was most sensitive to cinnamaldehyde and lauric acid, with MIC values <1.5 mM. Most antibacterial effects of binary combinations were additive, however, for thymol and carvacrol, synergism could be observed. In vitro results demonstrate the antibacterial action of certain essential oil components and organic acids against B. hyodysenteriae.
17 citations
TL;DR: A high prevalence of 33% of Salmonella Enteritidis in Brussels combined with dense pigeon populations suggest that feral pigeons may constitute a significant, but unrevealed reservoir for contracting salmonellosis in the urban environment.
15 citations
TL;DR: Page 4173, “Primer probe and design” paragraph, lines 9 and 10: “5.8S Chytr (5′-TCGGTTCTCTCTAGGCAACAGTTT-3-3)′” should read “7.2S ChYtr ( 5′-AGCCAAGAGATCCGTTGTCAAA-3′).”
Abstract: Volume 51, no. 12, p. [4173–4177][1], 2013. Page 4173, “Primer probe and design” paragraph, lines 9 and 10: “5.8S Chytr (5′-TCGGTTCTCTAGGCAACAGTTT-3)′” should read “5.8S Chytr (5′-AGCCAAGAGATCCGTTGTCAAA-3′).”
Page 4173, “Primer probe and design” paragraph, line 11: “
TL;DR: The apparent absence (prevalence: <1.3%) of a reservoir in healthy house sparrows and the association of infection with clinical disease suggests that the impact of Salmonella Typhimurium on house sp Sparrows is largely driven by the risk of exogenous exposure to pathogenic Salmoneella TyphimURium strains.
Abstract: In recent decades major declines in urban house sparrow (Passer domesticus) populations have been observed in north-western European cities, whereas suburban and rural house sparrow populations have remained relatively stable or are recovering from previous declines. Differential exposure to avian pathogens known to cause epidemics in house sparrows may in part explain this spatial pattern of declines. Here we investigate the potential effect of urbanization on the development of a bacterial pathogen reservoir in free-ranging house sparrows. This was achieved by comparing the prevalence of Salmonella enterica subspecies enterica serotype Typhimurium in 364 apparently healthy house sparrows captured in urban, suburban and rural regions across Flanders, Belgium between September 2013 and March 2014. In addition 12 dead birds, received from bird rescue centers, were necropsied. The apparent absence of Salmonella Typhimurium in fecal samples of healthy birds, and the identification of only one house sparrow seropositive for Salmonella spp., suggests that during the winter of 2013–2014 these birds did not represent any considerable Salmonella Typhimurium reservoir in Belgium and thus may be considered naive hosts, susceptible to clinical infection. This susceptibility is demonstrated by the isolation of two different Salmonella Typhimurium strains from two of the deceased house sparrows: one DT99, typically associated with disease in pigeons, and one DT195, previously associated with a passerine decline. The apparent absence (prevalence: <1.3%) of a reservoir in healthy house sparrows and the association of infection with clinical disease suggests that the impact of Salmonella Typhimurium on house sparrows is largely driven by the risk of exogenous exposure to pathogenic Salmonella Typhimurium strains. However, no inference could be made on a causal relationship between Salmonella infection and the observed house sparrow population declines.
TL;DR: It is demonstrated that pigeons are frequently exposed to mycotoxins such as DON, which can affect the outcome of a Salmonella infection, which suggests that DON can promote the spread of the bacterium within pigeon populations.
Abstract: Seed-based pigeon diets could be expected to result in exposure of pigeons to mycotoxins such as deoxynivalenol (DON). Ingestion of low to moderate contamination levels of DON may impair intestinal health, immune function and/or pathogen fitness, resulting in altered host-pathogen interactions and thus different outcome of infections. Here we demonstrate that DON was one of the most frequently detected mycotoxins in seed-based racing pigeons feed, contaminating 5 out of 10 samples (range 177–1,466 μg/kg). Subsequently, a toxicokinetic analysis revealed a low absolute oral bioavailability (F) of DON in pigeons (30.4%), which is comparable to other avian species. Furthermore, semi-quantitative analysis using high-resolution mass spectrometry revealed that DON-3α-sulphate is the major metabolite of DON in pigeons after intravenous as well as oral administration. Following ingestion of DON contaminated feed, the intestinal epithelial cells are exposed to significant DON concentrations which eventually may affect intestinal translocation and colonization of bacteria. Feeding pigeons a DON contaminated diet resulted in an increased percentage of pigeons shedding Salmonella compared to birds fed control diet, 87 ± 17% versus 74 ± 13%, respectively. However, no impact of DON was observed on the Salmonella induced disease signs, organ lesions, faecal and organ Salmonella counts. The presented risk assessment indicates that pigeons are frequently exposed to mycotoxins such as DON, which can affect the outcome of a Salmonella infection. The increasing number of pigeons shedding Salmonella suggests that DON can promote the spread of the bacterium within pigeon populations.
Journal Article•
TL;DR: Although squamous cell carcinomas in tortoises show similar predilection sites and gross pathologic features, the BCCs described in this report were characterized by a remarkably fast and highly infiltrative growth in comparison to SCCs.
Abstract: Neoplastic disorders are frequently encountered in the practice of reptile medicine. Herein we report the clinical behavior, antemortem diagnosis, and histopathologic characteristics of a recurrent intraoral keratinizing basal cell carcinoma (BCC) and a metastatic BCC of the carapace in 2 Hermann's tortoises (Testudo hermanni). Although squamous cell carcinomas (SCCs) in tortoises show similar predilection sites and gross pathologic features, the BCCs described in our report were characterized by a remarkably fast and highly infiltrative growth in comparison to SCCs. Accordingly, early diagnosis including reliable discrimination from SCC is essential toward the management of this neoplastic entity in tortoises.
TL;DR: The efficacy of GAM against O. rhinotracheale was demonstrated, especially in the lung tissue, however, the PO bolus administration of the commercially available product was not as efficacious as the SC bolus.
Abstract: Ornithobacterium rhinotracheale is an avian respiratory pathogen that affects turkeys. The objective of this study was to evaluate the clinical efficacy of gamithromycin (GAM) against O. rhinotracheale in turkeys. The birds were inoculated oculonasally with 108 colony-forming units (cfu) of O. rhinotracheale, preceded by infection with avian metapneumovirus. In addition to a negative (CONTR−) and a positive control group (CONTR+) there were two treated groups administered GAM (6 mg/kg) either subcutaneously (GAM SC) or orally (GAM PO) by administration as a single bolus at one-day post-bacterial infection (p.b.i.). From the start of the avian metapneumovirus infection until the end of the experiment, the turkeys were examined clinically and scored daily. In addition, tracheal swabs were collected at several days p.b.i. Necropsy was performed at 4, 8 and 12 days p.b.i. to evaluate the presence of gross lesions, and to collect trachea and lung tissue samples and air sac swabs for O. rhinotracheale q...
Journal Article•
TL;DR: An extensive field survey is organized to study the ecology of Psychrophrynella illimani, a critically endangered species endemic to a single valley in Bolivia that has not been reported on again since its discovery in 2002 and provides new information on its morphology, ecology, and reproductive behaviour.
Abstract: Amphibian populations have been declining worldwide for decades with a multitude of causes having been identified. Conservationists try to reverse the situation, but for many species, important information on distribution, habitat and ecology are missing, which makes the assessment of conservation priorities problematic. Although South America holds the largest number of extant amphibian species in the world, many of them are poorly studied. This is also the case for most species of Psychrophrynella, a genus of cold-adapted frogs occurring in the high Andes, the majority of which having only recently been described. We organized an extensive field survey to study the ecology of Psychrophrynella illimani, a critically endangered species endemic to a single valley in Bolivia that has not been reported on again since its discovery in 2002. We found P. illimani to be locally common and here report new localities, extending its known distribution. Furthermore, we provide new information on its morphology, ecology, and reproductive behaviour and describe for the first time its call. We also identify and discuss several threats that might affect this species' survival.
TL;DR: The recurrent course of an outbreak of common midwife toad virus in an isolated population (Staphorst) of common spadefoot toads (Pelobates fuscus) in The Netherlands from 2012 to 2015 is described.
Abstract: Viruses in the genus Ranavirus (family Iridoviridae) are known to have the potential to adversely affect fish, amphibians, and reptiles. Ranaviruses are associated with large-scale die-offs and rapid population declines in amphibians. The development and progression of an outbreak, however, vary greatly depending on the host species and geographic location. We describe the recurrent course of an outbreak of common midwife toad virus in an isolated population (Staphorst) of common spadefoot toads (Pelobates fuscus) in The Netherlands from 2012 to 2015. After initial mass mortality of toad larvae in 2012, no mass mortality was recorded in 2013 and 2014. In 2015, however, a recurrent outbreak of the virus is believed to have caused high mortality rates among this species in the Staphorst population.
TL;DR: It is shown that a CMTV-like ranavirus can persist long term in an ecosystem, affecting a diversity of amphibian species and life stages for a prolonged period, and the importance of monitoring the modes of spread for ranaviruses and their impact on amphibian populations is illustrated.
Abstract: The ranaviruses are an emerging group of viruses that infect amphibians, fish, and reptiles. Although ranaviruses have not been linked to extinctions, emergence in amphibian communities has resulted in population declines for some species. We present the results of ranavirus-associated mortality in a Dutch national park in the aftermath of an outbreak associated with a common midwife toad virus (CMTV)-like ranavirus. We monitored five bodies of water across Dwingelderveld National Park, the Netherlands, in 2011-13. Dead and live amphibians were counted weekly July-September and every 2 wk in June and October. Dead amphibians were collected and tested for ranavirus infection. In addition, we measured biologic, chemical, and physical site characteristics to test for a correlation with ranavirus-associated mortality. Ranavirus infection was widespread in our study area and we observed nearly continuous presence of dead, ranavirus-infected amphibians in the presence of asymptomatic, live amphibians throughout our study. Fatalities occurred in larval, subadult, and adult amphibians. Ranavirus infection prevalence (based on fatal cases) was significantly associated with increasing fractions of adults and subadults compared to juveniles and larvae in the population, but was unrelated to any other measured site characteristics. Our findings showed that a CMTV-like ranavirus can persist long term in an ecosystem, affecting a diversity of amphibian species and life stages for a prolonged period. This study illustrates the importance of monitoring the modes of spread for ranaviruses and their impact on amphibian populations.