scholarly journals Understanding potential implications for non-trophic parasite transmission based on vertebrate behavior at mesocarnivore carcass sites

Author(s):  
Moisés Gonzálvez ◽  
Carlos Martínez-Carrasco ◽  
Marcos Moleón

AbstractHigh infection risk is often associated with aggregations of animals around attractive resources. Here, we explore the behavior of potential hosts of non-trophically transmitted parasites at mesocarnivore carcass sites. We used videos recorded by camera traps at 56 red fox (Vulpes vulpes) carcasses and 10 carcasses of other wild carnivore species in three areas of southeastern Spain. Scavenging species, especially wild canids, mustelids and viverrids, showed more frequent rubbing behavior at carcass sites than non-scavenging and domestic species, suggesting that they could be exposed to a higher potential infection risk. The red fox was the species that most frequently contacted carcasses and marked and rubbed carcass sites. Foxes contacted heterospecific carcasses more frequently and earlier than conspecific ones and, when close contact occurred, it was more likely to be observed at heterospecific carcasses. This suggests that foxes avoid contact with the type of carcass and time period that have the greatest risk as a source of parasites. Overall, non-trophic behaviors of higher infection risk were mainly associated with visitor-carcass contact and visitor contact with feces and urine, rather than direct contact between visitors. Moreover, contact events between scavengers and carnivore carcasses were far more frequent than consumption events, which suggests that scavenger behavior is more constrained by the risk of acquiring meat-borne parasites than non-trophically transmitted parasites. This study contributes to filling key gaps in understanding the role of carrion in the landscape of disgust, which may be especially relevant in the current global context of emerging and re-emerging pathogens. Graphical abstract

2021 ◽  
Author(s):  
Gonzálvez Moisés ◽  
Carlos Martínez-Carrasco ◽  
Moleón Marcos

Abstract The spatiotemporal distribution of parasites in ecosystems is heterogeneous. High infection risk is often associated with aggregations of animals around attractive resources. Here, we explore the behavior of potential hosts of non-trophically transmitted parasites at mesocarnivore carcass sites. We used videos recorded by camera traps at 56 red fox (Vulpes vulpes) carcasses and 10 carcasses of other wild carnivore species in three areas of southeastern Spain. In general, scavenging species, especially wild canids, mustelids and viverrids that display rubbing behavior, were more exposed to infection risk at carnivore carcass sites than non-scavenging and domestic species. The red fox was the species that most frequently contacted carcasses and marked and rubbed carcass sites. Foxes contacted heterospecific carcasses more frequently and earlier than conspecific ones, and close contact was more frequently observed at heterospecific carcasses. Thus, foxes seemed to avoid contacting carcasses in those periods and at carcass types of maximum risk of acquiring parasites. Overall, our results suggest that infection risk at carnivore carcass sites may take place mainly for visitor-carcass contact or contact with feces and urine rather than direct contact between visitors. Moreover, contact events between scavengers and carnivore carcasses are far more frequent than consumption events, which indicates that scavenger behavior is more constrained by the risk of acquiring meat-borne parasites than non-trophically transmitted parasites. This study contributes to filling key gaps in understanding the role of carrion in the landscape of disgust, which may be especially relevant in the current global context of emerging and re-emerging pathogens.


2020 ◽  
Author(s):  
Sarah J Campbell ◽  
Wilbur Ashley ◽  
Margarita Gil-Fernandez ◽  
Thomas M. Newsome ◽  
Francesca Di Giallonardo ◽  
...  

AbstractThe Red fox (Vulpes vulpes) has established large populations in Australia’s urban and rural areas since its introduction following European settlement. Foxes’ cryptic and highly adaptable nature allows them to invade cities and live among humans while remaining largely unnoticed. Urban living and access to anthropogenic food resources also influences fox ecology. Urban foxes grow larger, live at higher densities and are more social than their rural counterparts. These ecological changes in urban red foxes are likely to impact the pathogens that they harbour, and foxes could pose a disease risk to humans and other species that share these urban spaces. To assess this possibility, we used a meta-transcriptomic approach to characterise the viromes of urban and rural foxes across the Greater Sydney region in Australia. Urban and rural foxes differed significantly in virome composition, with rural foxes harbouring a greater abundance of viruses compared to their urban counterparts. In contrast, urban fox viromes comprised a greater diversity of viruses compared to rural foxes. We identified nine potentially novel vertebrate-associated viruses in both urban and rural foxes, some of which are related to viruses associated with disease in domestic species and humans. These included members of the Astroviridae, Picobirnaviridae, Hepeviridae and Picornaviridae as well as rabbit haemorrhagic disease virus-2 (RHDV2). This study sheds light on the viruses carried by urban and rural foxes and emphasises the need for greater genomic surveillance of foxes and other invasive species at the human-wildlife interface.ImportanceUrbanisation of wild environments is increasing as human populations continue to expand. Remnant pockets of natural environments and other green spaces in urban landscapes provide invasive wildlife such as red foxes with refuges within urban areas, where they thrive on the food resources provisioned by humans. Close contact between humans, domestic species and foxes likely increases the risk of novel pathogen emergence. Indeed, the vast majority of emerging infectious diseases in humans originate in wild animals. Here, we explored potential differences in viromes between urban fox invaders and their rural counterparts. Viromes of foxes and their ectoparasites comprise a diversity of viruses including those from the Astroviridae, Picobirnaviridae, Hepeviridae, Caliciviridae and Picornaviridae. Microbial surveillance in foxes and other urban wildlife is vital for monitoring viral emergence and for the prevention of infectious diseases.


PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243026
Author(s):  
Rajiv Bhatia ◽  
Jeffrey Klausner

We describe a method to estimate individual risks of hospitalization and death attributable to non-household and household transmission of SARS-CoV-2 using available public data on confirmed-case incidence data along with estimates of the clinical fraction, timing of transmission, isolation adherence, secondary infection risks, contact rates, and case-hospitalization and case-fatality ratios. Using the method, we estimate that risks for a 90-day period at the median daily summertime U.S. county confirmed COVID-19 case incidence of 10.8 per 100,000 and pre-pandemic contact rates range from 0.4 to 8.9 per 100,000 for the four deciles of age between 20 and 60 years. The corresponding 90-day period risk of hospitalization ranges from 13.7 to 69.2 per 100,000. Assuming a non-household secondary infection risk of 4% and pre-pandemic contact rates, the share of transmissions attributable to household settings ranges from 73% to 78%. These estimates are sensitive to the parameter assumptions; nevertheless, they are comparable to the COVID-19 hospitalization and fatality rates observed over the time period. We conclude that individual risk of hospitalization and death from SARS-CoV-2 infection is calculable from publicly available data sources. Access to publicly reported infection incidence data by setting and other exposure characteristics along with setting specific estimates of secondary infection risk would allow for more precise individual risk estimation.


2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Sarah J Campbell ◽  
Wilbur Ashley ◽  
Margarita Gil-Fernandez ◽  
Thomas M Newsome ◽  
Francesca Di Giallonardo ◽  
...  

Abstract The Red fox (Vulpes vulpes) has established large populations in Australia’s urban and rural areas since its introduction following European settlement. The cryptic and highly adaptable nature of foxes allows them to invade cities and live among humans whilst remaining largely unnoticed. Urban living and access to anthropogenic food resources also influence fox ecology. Urban foxes grow larger, live at higher densities, and are more social than their rural counterparts. These ecological changes in urban red foxes are likely to impact the pathogens that they harbour, and foxes could pose a disease risk to humans and other species that share these urban spaces. To investigate this possibility, we used a meta-transcriptomic approach to characterise the virome of urban and rural foxes across the Greater Sydney region in Australia. Urban and rural foxes differed significantly in virome composition, with rural foxes harbouring a greater abundance of viruses compared to their urban counterparts. We identified ten potentially novel vertebrate-associated viruses in both urban and rural foxes, some of which are related to viruses associated with disease in domestic species and humans. These included members of the Astroviridae, Picobirnaviridae, Hepeviridae, and Picornaviridae as well as rabbit haemorrhagic disease virus-2. This study sheds light on the viruses carried by urban and rural foxes and emphasises the need for greater genomic surveillance of foxes and other invasive species at the human–wildlife interface.


2017 ◽  
Vol 23 (3) ◽  
pp. 302 ◽  
Author(s):  
Paul D. Meek ◽  
Jason Wishart

Camera traps provide a novel and quasicovert method of gathering information on animal behaviour that may otherwise remain undetected without sophisticated and expensive filming equipment. In a rangelands pest management project at Mt Hope in the central west of New South Wales, Australia, we recorded foxes seemingly hunting kangaroos on three occasions. While we did not record direct instances of predation, our observations provide camera trap photographic evidence suggesting that foxes will attempt to tackle mammals above the critical weight range, including large macropod species such as western grey kangaroos.


2020 ◽  
Vol 9 (3) ◽  
pp. 657 ◽  
Author(s):  
Hiroshi Nishiura

To understand the time-dependent risk of infection on a cruise ship, the Diamond Princess, I estimated the incidence of infection with novel coronavirus (COVID-19). The epidemic curve of a total of 199 confirmed cases was drawn, classifying individuals into passengers with and without close contact and crew members. A backcalculation method was employed to estimate the incidence of infection. The peak time of infection was seen for the time period from 2 to 4 February 2020, and the incidence has abruptly declined afterwards. The estimated number of new infections among passengers without close contact was very small from 5 February on which a movement restriction policy was imposed. Without the intervention from 5 February, it was predicted that the cumulative incidence with and without close contact would have been as large as 1373 (95% CI: 570, 2176) and 766 (95% CI: 587, 946) cases, respectively, while these were kept to be 102 and 47 cases, respectively. Based on an analysis of illness onset data on board, the risk of infection among passengers without close contact was considered to be very limited. Movement restriction greatly reduced the number of infections from 5 February onwards.


Author(s):  
Khalid Al-Ahmadi ◽  
Sabah Alahmadi ◽  
Ali Al-Zahrani

Middle East respiratory syndrome coronavirus (MERS-CoV) is a great public health concern globally. Although 83% of the globally confirmed cases have emerged in Saudi Arabia, the spatiotemporal clustering of MERS-CoV incidence has not been investigated. This study analysed the spatiotemporal patterns and clusters of laboratory-confirmed MERS-CoV cases reported in Saudi Arabia between June 2012 and March 2019. Temporal, seasonal, spatial and spatiotemporal cluster analyses were performed using Kulldorff’s spatial scan statistics to determine the time period and geographical areas with the highest MERS-CoV infection risk. A strongly significant temporal cluster for MERS-CoV infection risk was identified between April 5 and May 24, 2014. Most MERS-CoV infections occurred during the spring season (41.88%), with April and May showing significant seasonal clusters. Wadi Addawasir showed a high-risk spatial cluster for MERS-CoV infection. The most likely high-risk MERS-CoV annual spatiotemporal clusters were identified for a group of cities (n = 10) in Riyadh province between 2014 and 2016. A monthly spatiotemporal cluster included Jeddah, Makkah and Taif cities, with the most likely high-risk MERS-CoV infection cluster occurring between April and May 2014. Significant spatiotemporal clusters of MERS-CoV incidence were identified in Saudi Arabia. The findings are relevant to control the spread of the disease. This study provides preliminary risk assessments for the further investigation of the environmental risk factors associated with MERS-CoV clusters.


2018 ◽  
Author(s):  
Shao-jie Zhang ◽  
Guo-Dong Wang ◽  
Pengcheng Ma ◽  
Liang-liang Zhang ◽  
Ting-Ting Yin ◽  
...  

AbstractDingoes (Canis dingo) are wild canids living in Australia. They have lived isolated from both the wild and the domestic ancestor and are a unique model for studying feralization, the process in which a domestic species escapes human control, adapts to the wild, and diverges from the domestic ancestor into a genetically distinct population. Here, we sequenced the genomes of 10 dingoes and 2 New Guinea Singing Dogs, to study the origins and feralization process of the dingo. Phylogenetic and demographic analyses show that dingoes originate from domestic dogs in southern East Asia, which migrated via Island Southeast Asia to reach Australia 4300-5000 years ago, and subsequently diverged into a genetically distinct population. Selection analysis identified 99 positively selected genes enriched in starch and fat metabolism pathways, indicating a diet change during feralization of dingoes. Interestingly, we found that 14 genes have shifted allele frequencies compared to dogs but not compared to wolves. This suggests that the selection affecting these genes during domestication of the wolf was reversed in the feralization process. One of these genes, ARHGEF7, may promote the formation of neural spine and synapses in hippocampal neurons. Functional assays showed that an A to G mutation in ARHGEF7, located in a transcription factor-binding site, decreases the endogenous expression. This suggests that ARHGEF7 may have been under selection for behavioral adaptations related to the transitions in environment both from wild to domestic and from domestic back to wild. Our results indicate that adaptation to domestication and feralization primarily affected different genomic regions, but that some genes, related to neurodevelopment, metabolism and reproduction, may have been reversibly affected in the two processes.


2010 ◽  
Vol 62 (3) ◽  
pp. 676-683 ◽  
Author(s):  
P. Sahota ◽  
G. Pandove ◽  
V. Achal ◽  
Y. Vikal

A defined substrate method media in bacteriological water testing kit (BWTK) has been developed to recover and detect the presence/absence of total coliforms and emerging pathogens from drinking water without the need for the confirmatory or complete tests. This method is based on technology that uses a hydrolysable substrate as a specific indicator- nutrient for the target microbes. To perform the test, one only has to add water to the ingredients in the BWTK and incubate at room temperature for a time period of 48 hrs. The target microbes remain viable in the positive kit for at least 10 days and further bacterial isolates from BWTK were characterized phenotypically, molecular identified by sequencing of 16SrRNA gene and antibiotic sensitivity was determined. All of the emerging bacterial isolates were haemolytic and multiple resistant to antibiotics. The epidemiological surveillance of drinking water revealed the occurrence of emerging pathogens responsible for causing acute gastrointestinal illness, soft tissue infections, meningitis, enteritis to acute mesenteric lymphadenitis as Yersinia enterocolitica (94%) and Aeromonas hydrophila (79%). The conventional methods (IS-10500-1991 BIS New Delhi, India) cannot predict the presence of these potentially enteropathogenic microorganisms in drinking water. There are currently no suitable microbiological criteria for the detection of emerging pathogens. In response to these limitations a BWTK has been developed for regularly monitoring of drinking water quality for appraisal to public health officials and take corrective measures regarding health risk when desired.


2016 ◽  
Vol 43 (8) ◽  
pp. 615 ◽  
Author(s):  
Stuart J. Dawson ◽  
Heather M. Crawford ◽  
Robert M. Huston ◽  
Peter J. Adams ◽  
Patricia A. Fleming

Context Predation is one of the key contributors to mortality in freshwater turtles. Confirming the identity of predators is an important step towards conservation management action. Throughout Australia, the red fox (Vulpes vulpes) is suspected to apply significant and unsustainable predation pressure to turtle populations, killing adults and depredating nests; however methods for confirming this are limited. Aims The present study used a range of methods to confirm predation of oblong turtle (Chelodina colliei) nests and adults by the introduced red fox. Methods First, depredated adult carapaces, and turtle egg-shell fragments from excavated nests were swabbed and analysed for trace DNA. Second, we used artificial turtle nests, monitored by camera traps, to analyse seasonal changes in the behaviour of foxes around sites where turtle nests are present, including over the nesting season. Last, we used scat analysis to identify the prevalence of turtle remains in fox diet. Key results Predominantly fox DNA was recovered from both adult carapaces and depredated eggs. In addition, camera traps recorded only foxes depredating artificial nests. Despite this evidence that foxes kill adults and excavated nests, we found that turtle remains were only a small part of the diet of foxes at this study site (hatchling or turtle egg shell were present in only 4% of 230 scats sampled). The diet of these foxes was largely anthropogenic-sourced foods, such as fruit (e.g. figs, grapes, melons; 81% of scats), sheep carrion (41%) and rodents (36%). Conclusions We conclude that DNA analysis, camera trapping and scat analysis are effective methods of identifying foxes as predators of adult turtle, and their nests. Furthermore, we found that anthropogenic foods (orchard crops, livestock or synanthropic species) may subsidise greater fox population size than might occur in their absence, thereby increasing potential pressure on these freshwater turtles. Implications Our findings give credence to the argument that foxes are effective predators of turtle adults and nests. In addition, the high proportion of anthropogenic food sources in the diet of foxes, and potential subsidisation, is an important consideration for land managers.


Sign in / Sign up

Export Citation Format

Share Document