scholarly journals Loss of migratory behaviour increases infection risk for a butterfly host

2015 ◽  
Vol 282 (1801) ◽  
pp. 20141734 ◽  
Author(s):  
Dara A. Satterfield ◽  
John C. Maerz ◽  
Sonia Altizer
Keyword(s):  
Human Activities ◽  
Wildlife Conservation ◽  
Protozoan Parasite ◽  
Infection Risk ◽  
Pathogen Transmission ◽  
Infection Prevalence ◽  
Evolutionary Divergence ◽  
Science Data ◽  
Long Distance ◽  
Southern Us

Long-distance animal migrations have important consequences for infectious disease dynamics. In some cases, migration lowers pathogen transmission by removing infected individuals during strenuous journeys and allowing animals to periodically escape contaminated habitats. Human activities are now causing some migratory animals to travel shorter distances or form sedentary (non-migratory) populations. We focused on North American monarch butterflies and a specialist protozoan parasite to investigate how the loss of migratory behaviours affects pathogen spread and evolution. Each autumn, monarchs migrate from breeding grounds in the eastern US and Canada to wintering sites in central Mexico. However, some monarchs have become non-migratory and breed year-round on exotic milkweed in the southern US. We used field sampling, citizen science data and experimental inoculations to quantify infection prevalence and parasite virulence among migratory and sedentary populations. Infection prevalence was markedly higher among sedentary monarchs compared with migratory monarchs, indicating that diminished migration increases infection risk. Virulence differed among parasite strains but was similar between migratory and sedentary populations, potentially owing to high gene flow or insufficient time for evolutionary divergence. More broadly, our findings suggest that human activities that alter animal migrations can influence pathogen dynamics, with implications for wildlife conservation and future disease risks.

Effect of host populations on the intensity of ticks and the prevalence of tick-borne pathogens: how to interpret the results of deer exclosure experiments

Parasitology ◽  
2008 ◽  
Vol 135 (13) ◽  
pp. 1531-1544 ◽  
Author(s):  
A. PUGLIESE ◽  
R. ROSÀ
Keyword(s):  
Ixodes Ricinus ◽  
Dynamic Models ◽  
Infection Risk ◽  
Northern Italy ◽  
Pathogen Transmission ◽  
Infection Prevalence ◽  
Tick Density ◽  
Dead End ◽  
Tick Borne Encephalitis ◽  
Experimental Plots

SUMMARYDeer are important blood hosts for feeding Ixodes ricinus ticks but they do not support transmission of many tick-borne pathogens, so acting as dead-end transmission hosts. Mathematical models show their role as tick amplifiers, but also suggest that they dilute pathogen transmission, thus reducing infection prevalence. Empirical evidence for this is conflicting: experimental plots with deer removal (i.e. deer exclosures) show that the effect depends on the size of the exclosure. Here we present simulations of dynamic models that take into account different tick stages, and several host species (e.g. rodents) that may move to and from deer exclosures; models were calibrated with respect to Ixodes ricinus ticks and tick-borne encephalitis (TBE) in Trentino (northern Italy). Results show that in small exclosures, the density of rodent-feeding ticks may be higher inside than outside, whereas in large exclosures, a reduction of such tick density may be reached. Similarly, TBE prevalence in rodents decreases in large exclosures and may be slightly higher in small exclosures than outside them. The density of infected questing nymphs inside small exclosures can be much higher, in our numerical example almost twice as large as that outside, leading to potential TBE infection risk hotspots.

scholarly journals Defining the risk landscape in the context of pathogen pollution: Toxoplasma gondii in sea otters along the Pacific Rim

2018 ◽  
Vol 5 (7) ◽  
pp. 171178 ◽  
Author(s):  
Tristan L. Burgess ◽  
M. Tim Tinker ◽  
Melissa A. Miller ◽  
James L. Bodkin ◽  
Michael J. Murray ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Population Density ◽  
Spatial Scale ◽  
Infection Risk ◽  
Pathogen Transmission ◽  
Small Scale ◽  
Infection Prevalence ◽  
Marine Animal ◽  
Sea Otter ◽  
Individual Level

Pathogens entering the marine environment as pollutants exhibit a spatial signature driven by their transport mechanisms. The sea otter ( Enhydra lutris ), a marine animal which lives much of its life within sight of land, presents a unique opportunity to understand land–sea pathogen transmission. Using a dataset on Toxoplasma gondii prevalence across sea otter range from Alaska to California, we found that the dominant drivers of infection risk vary depending upon the spatial scale of analysis. At the population level, regions with high T. gondii prevalence had higher human population density and a greater proportion of human-dominated land uses, suggesting a strong role for population density of the felid definitive host of this parasite. This relationship persisted when a subset of data were analysed at the individual level: large-scale patterns in sea otter T. gondii infection prevalence were largely explained by individual exposure to areas of high human housing unit density, and other landscape features associated with anthropogenic land use, such as impervious surfaces and cropping land. These results contrast with the small-scale, within-region analysis, in which age, sex and prey choice accounted for most of the variation in infection risk, and terrestrial environmental features provided little variation to help in explaining observed patterns. These results underscore the importance of spatial scale in study design when quantifying both individual-level risk factors and landscape-scale variation in infection risk.

scholarly journals Reactivation of latent infections with migration shapes population-level disease dynamics

2020 ◽  
Vol 287 (1935) ◽  
pp. 20201829 ◽  
Author(s):  
Daniel J. Becker ◽  
Ellen D. Ketterson ◽  
Richard J. Hall
Keyword(s):  
Mechanistic Model ◽  
Temporal Patterns ◽  
Population Level ◽  
Pathogen Transmission ◽  
Infection Prevalence ◽  
Disease Dynamics ◽  
Latent Infections ◽  
Spatial And Temporal Patterns ◽  
Long Distance ◽  
Spatio Temporal

Annual migration is common across animal taxa and can dramatically shape the spatial and temporal patterns of infectious disease. Although migration can decrease infection prevalence in some contexts, these energetically costly long-distance movements can also have immunosuppressive effects that may interact with transmission processes in complex ways. Here, we develop a mechanistic model for the reactivation of latent infections driven by physiological changes or energetic costs associated with migration (i.e. ‘migratory relapse’) and its effects on disease dynamics. We determine conditions under which migratory relapse can amplify or reduce infection prevalence across pathogen and host traits (e.g. infectious periods, virulence, overwinter survival, timing of relapse) and transmission phenologies. We show that relapse at either the start or end of migration can dramatically increase prevalence across the annual cycle and may be crucial for maintaining pathogens with low transmissibility and short infectious periods in migratory populations. Conversely, relapse at the start of migration can reduce the prevalence of highly virulent pathogens by amplifying culling of infected hosts during costly migration, especially for highly transmissible pathogens and those transmitted during migration or the breeding season. Our study provides a mechanistic foundation for understanding the spatio-temporal patterns of relapsing infections in migratory hosts, with implications for zoonotic surveillance and understanding how infection patterns will respond to shifts in migratory propensity associated with environmental change. Further, our work suggests incorporating within-host processes into population-level models of pathogen transmission may be crucial for reconciling the range of migration–infection relationships observed across migratory species.

scholarly journals Reactivation of latent infections with migration shapes population-level disease dynamics

2020 ◽  
Author(s):  
Daniel J. Becker ◽  
Ellen D. Ketterson ◽  
Richard J. Hall
Keyword(s):  
Mechanistic Model ◽  
Population Level ◽  
Pathogen Transmission ◽  
Infection Prevalence ◽  
Disease Dynamics ◽  
Latent Infections ◽  
Migratory Species ◽  
Spatial And Temporal Patterns ◽  
Long Distance ◽  
Highly Virulent

AbstractAnnual migration is common across animal taxa and can dramatically shape the spatial and temporal patterns of infectious disease. Although migration can decrease infection prevalence in some contexts, these energetically costly long-distance movements can also have immunosuppressive effects that may interact with transmission processes in complex ways. Here we develop a mechanistic model for the reactivation of latent infections driven by physiological changes or energetic costs associated with migration (i.e., “migratory relapse”) and its effects on disease dynamics. We determine conditions under which migratory relapse can amplify or reduce infection prevalence across pathogen and host traits (e.g., infectious periods, virulence, overwinter survival, timing of relapse) and transmission phenologies. We show that relapse at either the start or end of migration can dramatically increase prevalence across the annual cycle and may be crucial for maintaining pathogens with low transmissibility and short infectious periods in migratory populations. Conversely, relapse at the start of migration can reduce the prevalence of highly virulent pathogens by amplifying culling of infected hosts during costly migration, especially for highly transmissible pathogens and those transmitted during migration or the breeding season. Our study provides a mechanistic foundation for understanding the spatiotemporal patterns of relapsing infections in migratory hosts, with implications for zoonotic surveillance and understanding how infection patterns will respond to shifts in migratory propensity associated with environmental change. Further, our work suggests incorporating within-host processes into population-level models of pathogen transmission may be crucial for reconciling the range of migration–infection relationships observed across migratory species.

scholarly journals Assessment of the American Flamingo distribution, trends, and important breeding areas

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244117
Author(s):  
Leopoldo Torres-Cristiani ◽  
Salima Machkour-M’Rabet ◽  
Sophie Calmé ◽  
Holger Weissenberger ◽  
Griselda Escalona-Segura
Keyword(s):  
The United States ◽  
Wide Distribution ◽  
Global Perspective ◽  
Range Extension ◽  
Technological Advancement ◽  
Science Data ◽  
Long Distance ◽  
The 1960S ◽  
American Flamingo ◽  
Phoenicopterus Ruber

The American Flamingo, Phoenicopterus ruber, is a charismatic bird distributed throughout the Caribbean, North and South America. Its wide distribution, the complexity of international monitoring due to its capacity for long-distance flying, and a focus mostly on local populations, make it difficult to understand the dynamics between sites. Here, we took advantage of the citizen eBird science project to present a global perspective on the distribution of the American Flamingo, and identify the potentially most important countries for breeding. We obtained 16,930 records for the Americas from the 1960s until October 2018, of which 9,283 could be used for our objectives. The eBird database indicated a considerable increase in the total number of records over the last decade (2010s), probably reflecting an increase in tourism facilities, research investment, technological advancement, interest in conservation, and the worldwide availability of eBird. We also observed a range extension in the Gulf of Mexico in the United States and a significant recolonization in the Florida Peninsula. The apparent range extension to the South is more likely to be linked to biases in the data; for example, in any given country the number of records might reflect either reporting efforts or actual numbers. eBird data confirmed that six countries host the main breeding colonies (Bahamas, Bonaire, Cuba, Ecuador, Mexico, and Venezuela). We suggest three additional countries as potential breeding areas for the species (Colombia, Curaçao, Turks and Caicos Islands) for which more field observations are necessary to support this possibility. This global appraisal of the distribution of the American Flamingo using citizen science data provides valuable information for national and international management and conservation programs such as the need to verify the species breeding status in areas where it appears to be expanding its distribution.

scholarly journals Priorities for the conservation of mammals in the Peruvian Amazon

Oryx ◽  
1995 ◽  
Vol 29 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Richard E. Bodmer
Keyword(s):  
International Trade ◽  
Human Activities ◽  
Wildlife Conservation ◽  
Peruvian Amazon ◽  
Animal Populations ◽  
Peruvian Amazonia ◽  
The Impact ◽  
Commercial Hunting

Setting priorities for wildlife conservation in the Peruvian Amazon must deal with a variety of issues, including subsistence and commercial hunting, loss of habitat from deforestation, and the international trade in wildlife and wildlife products. However, what is the rank of these priorities for wildlife conservation in Peruvian Amazonia? One way to evaluate priorities for wildlife conservation is by determining how different human activities affect the number of animals removed from the populations. This yields a measure of the impact of these activities on animal populations and enables wildlife managers to rank priorities for wildlife conservation efforts.

scholarly journals Citizen science monitoring reveals a significant, ongoing decline of the Endangered Carnaby's black-cockatoo Calyptorhynchus latirostris

Oryx ◽  
2015 ◽  
Vol 50 (4) ◽  
pp. 626-635 ◽  
Author(s):  
Matthew R. Williams ◽  
Colin J. Yates ◽  
William D. Stock ◽  
Geoff W. Barrett ◽  
Hugh C. Finn
Keyword(s):  
Citizen Science ◽  
Wildlife Conservation ◽  
Sampling Site ◽  
Significant Decline ◽  
Science Data ◽  
Spatial And Temporal Scales ◽  
Site Characteristics ◽  
Declining Species ◽  
Scientific Value ◽  
Survey Effort

AbstractCitizen science monitoring programmes are making increasingly important contributions to wildlife conservation, often at spatial and temporal scales unachievable by individual or teams of researchers. They are particularly valuable in estimating population trends and management impacts, and thus informing effective conservation decisions for declining species. The quality and potential biases of citizen science data are of concern, however, and appropriate experimental design and analysis are needed to ensure that the maximum scientific value is extracted. We investigated these issues in a citizen science survey of the Endangered Carnaby's black-cockatoo Calyptorhynchus latirostris. Since 2010, citizen scientists have conducted synchronized annual counts of Carnaby's black-cockatoo at roost sites to estimate the population trend. Survey effort was substantial, with c. 150 sites surveyed by > 260 volunteers each year. Relatively few sites were occupied, however, and only 42 (16%) of the 265 sites surveyed in total accounted for 95% of all observations. Many sites were empty and survey effort was often inconsistent. Taking these issues into account, analysis showed a statistically significant decline in roost occupancy rate and a non-significant decline in the mean size of roosting flocks, with an estimated overall trend of 14% decline per annum in the number of roosting birds. We highlight three important issues for citizen science monitoring programmes: the need to maintain regular surveys of sample sites to avoid patchy data, use an appropriate model that accounts for variable survey effort, high frequency of zero counts, and sampling site turnover, and incorporate information on site characteristics to help explain variation.

Regional seroprevalence of Toxoplasma gondii antibodies in feral and stray cats (Felis catus) from Tasmania

2014 ◽  
Vol 62 (4) ◽  
pp. 272 ◽  
Author(s):  
Bronwyn A. Fancourt ◽  
Robert B. Jackson
Keyword(s):  
Toxoplasma Gondii ◽  
Wildlife Conservation ◽  
Protozoan Parasite ◽  
Felis Catus ◽  
Rapid Decline ◽  
Tasmanian Devil ◽  
Igg Antibodies ◽  
Feral Cat ◽  
Modified Agglutination Test ◽  
Stray Cats

Toxoplasma gondii is a cosmopolitan protozoan parasite of felids that also has significant implications for the health of wildlife, livestock and humans worldwide. In Australia, feral, stray and domestic cats (Felis catus) are the most important definitive host of T. gondii as they are the only species that can excrete the environmentally resistant oocysts that provide a major source of infection for mammals and birds. In Tasmania, the rapid decline of the Tasmanian devil (Sarcophilus harrisii) may allow an increase in feral cat abundance, thereby increasing the risk of T. gondii infection to a range of susceptible wildlife species. At present, there is scant information on the prevalence of T. gondii infection in feral cat populations across Tasmania. We tested feral cats from 13 regions across Tasmania for the presence of T. gondii–specific IgG antibodies using a modified agglutination test. Results were combined with serosurveys from three previous studies to enable a comparison of seroprevalence among 14 regions across Tasmania. We found that 84.2% (224 of 266) of cats tested positive for T. gondii IgG antibodies. This is among the highest rates of prevalence recorded from Australia, and significantly higher than for most other countries. Adult cats had higher seroprevalence than kittens but there was no difference between sexes. In Tasmania, seroprevalence was high in 12 of 14 regions (range: 79.3–100.0%), with only two regions (Tasman Island and Southern Tasmania) recording significantly lower seroprevalence (≤50%). This suggests a high risk of infection across Tasmania, and has significant implications for wildlife conservation should feral cat abundance increase with the ongoing declines in Tasmanian devils.

scholarly journals Estimating the annual distribution of monarch butterflies in Canada over 16 years using citizen science data

FACETS ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 238-253
Author(s):  
D. T. Tyler Flockhart ◽  
Maxim Larrivée ◽  
Kathleen L. Prudic ◽  
D. Ryan Norris
Keyword(s):  
North America ◽  
Citizen Science ◽  
Habitat Restoration ◽  
Danaus Plexippus ◽  
The United States ◽  
Science Data ◽  
Eastern Canada ◽  
Long Distance ◽  
Monarch Butterflies ◽  
Breeding Distribution

Monarch butterflies ( Danaus plexippus, Linnaeus, 1758) are comprised of two migratory populations separated by the Rocky Mountains and are renowned for their long-distance movements among the United States, Canada, and Mexico. Both populations have declined over several decades across North America prompting all three countries to evaluate conservation efforts. Monitoring monarch distribution and abundance is a necessary aspect of ongoing management in Canada where they are a species at risk. We used presence-only data from two citizen science data sets to estimate the annual breeding distribution of monarch butterflies in Canada between 2000 and 2015. Monarch breeding distribution in Canada varied widely among years owing to natural variation, and when considering the upper 95% of the probability of occurrence, the annual mean breeding distribution in Canada was 484 943 km2 (min: 173 449 km2; max: 1 425 835 km2). The area of occurrence was approximately an order of magnitude larger in eastern Canada than in western Canada. Habitat restoration for monarch butterflies in Canada should prioritize productive habitats in southern Ontario where monarchs occur annually and, therefore, likely contribute most to the long-term viability of monarchs in eastern North America. Overall, our assessment sets the geographic context to develop successful management strategies for monarchs in Canada.

scholarly journals Modelling the direct virus exposure risk associated with respiratory events

2022 ◽  
Vol 19 (186) ◽  
Author(s):  
Jietuo Wang ◽  
Federico Dalla Barba ◽  
Alessio Roccon ◽  
Gaetano Sardina ◽  
Alfredo Soldati ◽  
...  
Keyword(s):  
Infection Risk ◽  
Pathogen Transmission ◽  
Mathematical Framework ◽  
Ambient Conditions ◽  
Systematic Assessment ◽  
Respiratory Events ◽  
Multi Phase Flow ◽  
Virus Exposure ◽  
Contagion Risk ◽  
Multi Phase

The outbreak of the COVID-19 pandemic highlighted the importance of accurately modelling the pathogen transmission via droplets and aerosols emitted while speaking, coughing and sneezing. In this work, we present an effective model for assessing the direct contagion risk associated with these pathogen-laden droplets. In particular, using the most recent studies on multi-phase flow physics, we develop an effective yet simple framework capable of predicting the infection risk associated with different respiratory activities in different ambient conditions. We start by describing the mathematical framework and benchmarking the model predictions against well-assessed literature results. Then, we provide a systematic assessment of the effects of physical distancing and face coverings on the direct infection risk. The present results indicate that the risk of infection is vastly impacted by the ambient conditions and the type of respiratory activity, suggesting the non-existence of a universal safe distance. Meanwhile, wearing face masks provides excellent protection, effectively limiting the transmission of pathogens even at short physical distances, i.e. 1 m.

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