scholarly journals Predictions of Disease Risk in Space and Time Based on the Thermal Physiology of an Amphibian Host-Pathogen Interaction

2020 ◽  
Vol 8 ◽  
Author(s):  
Julia M. Sonn ◽  
Warren P. Porter ◽  
Paul D. Mathewson ◽  
Corinne L. Richards-Zawacki
Keyword(s):  
Disease Risk ◽  
Mechanistic Modeling ◽  
Biophysical Model ◽  
Infection Prevalence ◽  
Body Temperatures ◽  
Space And Time ◽  
Host Body ◽  
Management Actions ◽  
Recruitment Failure ◽  
Host Pathogen

Emerging infectious diseases have been responsible for declines and extinctions in a growing number of species. Predicting disease variables like infection prevalence and mortality and how they vary in space and time will be critical to understanding how host-pathogen dynamics play out in natural environments and will help to inform management actions. The pandemic disease chytridiomycosis, caused by the fungal pathogen, Batrachochytrium dendrobatidis (Bd), has been implicated in declines in hundreds of amphibian species worldwide. We used field-collected measurements of host body temperatures and other physiological parameters to develop a mechanistic model of disease risk in a declining amphibian, the Northern cricket frog (Acris crepitans). We first used a biophysical model to predict host body temperatures across the species range in the eastern United States. We then used empirically derived relationships between host body temperature, infection prevalence and survival to predict where and when the risk of Bd-related declines is greatest. Our model predicts that pathogen prevalence is greatest, and survival of infected A. crepitans frogs is lowest, just prior to breeding when host body temperatures are low. Taken together, these results suggest that Bd poses the greatest threat to short-lived A. crepitans populations in the northern part of this host’s range and that disease-related recruitment failure may be common. Furthermore, our study demonstrates the utility of mechanistic modeling approaches for predicting disease outbreaks and dynamics in animal hosts.

scholarly journals Impact of the experimental removal of lizards on Lyme disease risk

2011 ◽  
Vol 278 (1720) ◽  
pp. 2970-2978 ◽  
Author(s):  
Andrea Swei ◽  
Richard S. Ostfeld ◽  
Robert S. Lane ◽  
Cheryl J. Briggs
Keyword(s):  
Lyme Disease ◽  
Disease Ecology ◽  
Disease Risk ◽  
Large Fraction ◽  
Host Community ◽  
Deer Mice ◽  
Infection Prevalence ◽  
Alternate Host ◽  
Experimental Removal ◽  
Tick Infection

The distribution of vector meals in the host community is an important element of understanding and predicting vector-borne disease risk. Lizards (such as the western fence lizard; Sceloporus occidentalis ) play a unique role in Lyme disease ecology in the far-western United States. Lizards rather than mammals serve as the blood meal hosts for a large fraction of larval and nymphal western black-legged ticks ( Ixodes pacificus —the vector for Lyme disease in that region) but are not competent reservoirs for the pathogen, Borrelia burgdorferi . Prior studies have suggested that the net effect of lizards is to reduce risk of human exposure to Lyme disease, a hypothesis that we tested experimentally. Following experimental removal of lizards, we documented incomplete host switching by larval ticks (5.19%) from lizards to other hosts. Larval tick burdens increased on woodrats, a competent reservoir, but not on deer mice, a less competent pathogen reservoir. However, most larvae failed to find an alternate host. This resulted in significantly lower densities of nymphal ticks the following year. Unexpectedly, the removal of reservoir-incompetent lizards did not cause an increase in nymphal tick infection prevalence. The net result of lizard removal was a decrease in the density of infected nymphal ticks, and therefore a decreased risk to humans of Lyme disease. Our results indicate that an incompetent reservoir for a pathogen may, in fact, increase disease risk through the maintenance of higher vector density and therefore, higher density of infected vectors.

Fire blight of pears in Israel: infection, prevalence, intensity and efficacy of management actions

2000 ◽  
Vol 28 (4) ◽  
pp. 361-374 ◽  
Author(s):  
D. Shtienberg ◽  
D. Oppenheim ◽  
Z. Herzog ◽  
Miriam Zilberstaine ◽  
G. Kritzman
Keyword(s):  
Fire Blight ◽  
Infection Prevalence ◽  
Management Actions

Diversifying forest communities may change Lyme disease risk: extra dimension to the dilution effect in Europe

Parasitology ◽  
2016 ◽  
Vol 143 (10) ◽  
pp. 1310-1319 ◽  
Author(s):  
SANNE C. RUYTS ◽  
EVY AMPOORTER ◽  
ELENA C. COIPAN ◽  
LANDER BAETEN ◽  
DIETER HEYLEN ◽  
...  
Keyword(s):  
North America ◽  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Disease Risk ◽  
Severe Disease ◽  
Dilution Effect ◽  
Ixodid Ticks ◽  
Infection Prevalence ◽  
Host Diversity ◽  
Pine Stands

SUMMARYLyme disease is caused by bacteria of theBorrelia burgdorferigenospecies complex and transmitted by Ixodid ticks. In North America only one pathogenic genospecies occurs, in Europe there are several. According to the dilution effect hypothesis (DEH), formulated in North America, nymphal infection prevalence (NIP) decreases with increasing host diversity since host species differ in transmission potential. We analysedBorreliainfection in nymphs from 94 forest stands in Belgium, which are part of a diversification gradient with a supposedly related increasing host diversity: from pine stands without to oak stands with a shrub layer. We expected changing tree species and forest structure to increase host diversity and decrease NIP. In contrast with the DEH, NIP did not differ between different forest types. Genospecies diversity however, and presumably also host diversity, was higher in oak than in pine stands. Infected nymphs tended to harbourBorrelia afzeliiinfection more often in pine stands whileBorrelia gariniiandBorrelia burgdorferiss. infection appeared to be more prevalent in oak stands. This has important health consequences, since the latter two cause more severe disease manifestations. We show that the DEH must be nuanced for Europe and should consider the response of multiple pathogenic genospecies.

scholarly journals Bird Lice (Mallophaga, Philopteridae, Menoponidae) of Domestic Pigeons on Specialized Pigeon Breeding Farms in Poltava

2017 ◽  
Vol 51 (6) ◽  
pp. 487-492 ◽  
Author(s):  
I. O. Kolomak ◽  
O. V. Kruchynenko
Keyword(s):  
Species Composition ◽  
Clinical Signs ◽  
Considerable Effect ◽  
Infection Prevalence ◽  
Host Body ◽  
Closed Type ◽  
High Prevalence ◽  
Breeding Farms ◽  
Domestic Pigeons ◽  
Pigeon Breeding

Abstract The species composition of pigeon lice parasitic on pigeons of ornamental breeds on the specialized closed-type farm (Poltava) was studied. Five species of these ectoparasites were registered: Columbicola columbae Linnaeus, 1758, Campanulotes compar Burmeister, 1838, (Philopteridae, Ischnocera), Bonomiella columbae Emerson, 1957, Hohorstiella lata Piaget, 1880 and Neocolpocephalus turbinatum (Denny, 1842) (Menoponidae, Amblycera). For each species, the data on infection prevalence, intensity and abundance were obtained. High prevalence of infection was registered for all pigeon lice species, while the intensity and, especially, the abundance were considerably different. C. columbae turned out to be the most abundant. B. columbae was rather common. The peculiarities of pigeon lice species localization on the host body were investigated. During the intensive infection of pigeons with lice, the complex of clinical signs is manifested, which testifies about considerable effect of these parasites on the host. The highest pathogenicity is characteristic for H. lata, which usually feeds on blood and lymph.

scholarly journals Seasonal migrations, body temperature fluctuations, and infection dynamics in adult amphibians

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4698 ◽  
Author(s):  
David R. Daversa ◽  
Camino Monsalve-Carcaño ◽  
Luis M. Carrascal ◽  
Jaime Bosch
Keyword(s):  
Seasonal Variation ◽  
Body Temperature ◽  
Annual Cycle ◽  
Batrachochytrium Dendrobatidis ◽  
Effective Means ◽  
The Body ◽  
Infection Prevalence ◽  
Body Temperatures ◽  
Annual Cycles ◽  
Prediction And Prevention

Risks of parasitism vary over time, with infection prevalence often fluctuating with seasonal changes in the annual cycle. Identifying the biological mechanisms underlying seasonality in infection can enable better prediction and prevention of future infection peaks. Obtaining longitudinal data on individual infections and traits across seasons throughout the annual cycle is perhaps the most effective means of achieving this aim, yet few studies have obtained such information for wildlife. Here, we tracked spiny common toads (Bufo spinosus) within and across annual cycles to assess seasonal variation in movement, body temperatures and infection from the fungal parasite, Batrachochytrium dendrobatidis (Bd). Across annual cycles, toads did not consistently sustain infections but instead gained and lost infections from year to year. Radio-tracking showed that infected toads lose infections during post-breeding migrations, and no toads contracted infection following migration, which may be one explanation for the inter-annual variability in Bd infections. We also found pronounced seasonal variation in toad body temperatures. Body temperatures approached 0 °C during winter hibernation but remained largely within the thermal tolerance range of Bd. These findings provide direct documentation of migratory recovery (i.e., loss of infection during migration) and escape in a wild population. The body temperature reductions that we observed during hibernation warrant further consideration into the role that this period plays in seasonal Bd dynamics.

Predicting walleye recruitment as a tool for prioritizing management actions

2015 ◽  
Vol 72 (5) ◽  
pp. 661-672 ◽  
Author(s):  
Gretchen J.A. Hansen ◽  
Stephen R. Carpenter ◽  
Jereme W. Gaeta ◽  
Joseph M. Hennessy ◽  
M. Jake Vander Zanden
Keyword(s):  
Data Availability ◽  
Degree Days ◽  
Shoreline Development ◽  
Thermal Habitat ◽  
Recruitment Success ◽  
Management Actions ◽  
Recruitment Failure ◽  
Successful Recruitment ◽  
Development Factor ◽  
Natural Reproduction

We classified walleye (Sander vitreus) recruitment with 81% accuracy (recruitment success and failure predicted correctly in 84% and 78% of lake-years, respectively) using a random forest model. Models were constructed using 2779 surveys collected from 541 Wisconsin lakes between 1989 and 2013 and predictor variables related to lake morphometry, thermal habitat, land use, and fishing pressure. We selected predictors to minimize collinearity while maximizing classification accuracy and data availability. The final model classified recruitment success based on lake surface area, water temperature degree-days, shoreline development factor, and conductivity. On average, recruitment was most likely in lakes larger than 225 ha. Low degree-days also increased the probability of successful recruitment, but primarily in lakes smaller than 150 ha. We forecasted the probability of walleye recruitment in 343 lakes considered for walleye stocking; lakes with high probability of natural reproduction but recent history of recruitment failure were prioritized for restoration stocking. Our results highlight the utility of models designed to predict recruitment for guiding management decisions, provided models are validated appropriately.

scholarly journals Multi-locus sequence analyses reveal a clonal L. borgpetersenii genotype in a heterogeneous invasive Rattus spp. community across the City of Johannesburg, South Africa

2020 ◽  
Author(s):  
Mark Hamish Moseley ◽  
Kovashnee Naidoo ◽  
Armanda Bastos ◽  
Liezl Retief ◽  
John Frean ◽  
...  
Keyword(s):  
Public Health ◽  
South Africa ◽  
Disease Risk ◽  
Cape Town ◽  
Infection Prevalence ◽  
Invasion History ◽  
Sequence Analyses ◽  
African Countries ◽  
Significant Public Health ◽  
The City

Abstract Background Rattus spp. are frequently implicated as key reservoir hosts for leptospirosis, one of the most common, but neglected, bacterial zoonoses in the world. Although leptospirosis is predicted to be a significant public health threat in Africa, studies from the continent are limited. Methods Rattus spp. (n=171) were sampled (January-May 2016) across the City of Johannesburg, South Africa’s largest inland metropole. Rattus spp. genetic diversity was evaluated by full length (1140 bp) cyt b sequencing of 42 samples. For comparison, a further 12 R. norvegicus samples collected in Cape Town, South Africa’s largest coastal metropole, were also genotyped. Leptospira infections were identified and genotyped using real-time PCR and multi-locus (lfb1, secY, lipL41) DNA sequencing. Results Five R. norvegicus haplotypes were identified across Johannesburg, four of which have not previously been detected in South Africa, and one in Cape Town. Across Johannesburg we identified a Leptospira spp. infection prevalence of 44% (75/171) and noted significant differences in the prevalence between administrative regions within the metropole. Multi-locus sequence analyses identified a clonal genotype consistent with L. borgpetersenii serogroup Javanica (serovar Ceylonica).Discussion The prevalence of infection identified in this study is amongst the highest detected in Rattus spp. in similar contexts across Africa. Despite the complex invasion history suggested by the heterogeneity in R. norvegicus haplotypes identified in Johannesburg, a single L. borgpetersenii genotype was identified in all infected rodents. The lack of L. interrogans in a rodent community dominated by R. norvegicus is notable given the widely recognised host-pathogen association between these species and evidence for L. interrogans infection in R. norvegicus in Cape Town. It is likely that environmental conditions (cold, dry winters) in Johannesburg may limit the transmission of L. interrogans. Spatial heterogeneity in prevalence suggest that local factors, such as land use, influence disease risk in the metropole. Conclusion In South Africa, as in other African countries, leptospirosis is likely underdiagnosed. The high prevalence of infection in urban rodents in Johannesburg suggest that further work is urgently needed to understand the potential public health risk posed by this neglected zoonotic pathogen.

scholarly journals Multi-locus sequence analyses reveal a clonal L. borgpetersenii genotype in a heterogeneous invasive Rattus spp. community across the City of Johannesburg, South Africa

2020 ◽  
Author(s):  
Mark Hamish Moseley ◽  
Kovashnee Naidoo ◽  
Armanda Bastos ◽  
Liezl Retief ◽  
John Frean ◽  
...  
Keyword(s):  
Public Health ◽  
South Africa ◽  
Disease Risk ◽  
Cape Town ◽  
Infection Prevalence ◽  
Invasion History ◽  
Sequence Analyses ◽  
African Countries ◽  
Significant Public Health ◽  
The City

Abstract BackgroundRattus spp. are frequently implicated as key reservoir hosts for leptospirosis, one of the most common, but neglected, bacterial zoonoses in the world. Although leptospirosis is predicted to be a significant public health threat in Africa, studies from the continent are limited. Methods Rattus spp. (n=171) were sampled (January-May 2016) across the City of Johannesburg, South Africa’s largest inland metropole. Rattus spp. genetic diversity was evaluated by full length (1140 bp) cyt b sequencing of 42 samples. For comparison, a further 12 R. norvegicus samples collected in Cape Town, South Africa’s largest coastal metropole, were also genotyped. Leptospira infections were identified and genotyped using real-time PCR and multi-locus (lfb1, secY, lipL41) DNA sequencing. Results Five R. norvegicus haplotypes were identified across Johannesburg, four of which have not previously been detected in South Africa, and one in Cape Town. Across Johannesburg we identified a Leptospira spp. infection prevalence of 44% (75/171) and noted significant differences in the prevalence between administrative regions within the metropole. Multi-locus sequence analyses identified a clonal genotype consistent with L. borgpetersenii serogroup Javanica (serovar Ceylonica).DiscussionThe prevalence of infection identified in this study is amongst the highest detected in Rattus spp. in similar contexts across Africa. Despite the complex invasion history suggested by the heterogeneity in R. norvegicus haplotypes identified in Johannesburg, a single L. borgpetersenii genotype was identified in all infected rodents. The lack of L. interrogans in a rodent community dominated by R. norvegicus is notable, given the widely recognised host-pathogen association between these species and evidence for L. interrogans infection in R. norvegicus in Cape Town. It is likely that environmental conditions (cold, dry winters) in Johannesburg may limit the transmission of L. interrogans. Spatial heterogeneity in prevalence suggest that local factors, such as land use, influence disease risk in the metropole. ConclusionIn South Africa, as in other African countries, leptospirosis is likely underdiagnosed. The high prevalence of infection in urban rodents in Johannesburg suggest that further work is urgently needed to understand the potential public health risk posed by this neglected zoonotic pathogen.

scholarly journals Multi-locus sequence analyses reveal a clonal L. borgpetersenii genotype in a heterogeneous invasive Rattus spp. community across the City of Johannesburg, South Africa

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Mark Moseley ◽  
Kovashnee Naidoo ◽  
Armanda Bastos ◽  
Liezl Retief ◽  
John Frean ◽  
...  
Keyword(s):  
Public Health ◽  
South Africa ◽  
Disease Risk ◽  
Cape Town ◽  
Infection Prevalence ◽  
Invasion History ◽  
Sequence Analyses ◽  
African Countries ◽  
Significant Public Health ◽  
The City

Abstract Background Rattus spp. are frequently implicated as key reservoir hosts for leptospirosis, one of the most common, but neglected, bacterial zoonoses in the world. Although leptospirosis is predicted to be a significant public health threat in Africa, studies from the continent are limited. Methods Rattus spp. (n = 171) were sampled (January–May 2016) across the City of Johannesburg, South Africa’s largest inland metropole. Rattus spp. genetic diversity was evaluated by full length (1140 bp) cyt b sequencing of 42 samples. For comparison, a further 12 Rattus norvegicus samples collected in Cape Town, South Africa’s largest coastal metropole, were also genotyped. Leptospira infections were identified and genotyped using real-time PCR and multi-locus (lfb1, secY and lipL41) DNA sequencing. Results Five R. norvegicus haplotypes were identified across Johannesburg, four of which have not previously been detected in South Africa, and one in Cape Town. Across Johannesburg we identified a Leptospira spp. infection prevalence of 44% (75/171) and noted significant differences in the prevalence between administrative regions within the metropole. Multi-locus sequence analyses identified a clonal genotype consistent with L. borgpetersenii serogroup Javanica (serovar Ceylonica). Discussion The prevalence of infection identified in this study is amongst the highest detected in Rattus spp. in similar contexts across Africa. Despite the complex invasion history suggested by the heterogeneity in R. norvegicus haplotypes identified in Johannesburg, a single L. borgpetersenii genotype was identified in all infected rodents. The lack of L. interrogans in a rodent community dominated by R. norvegicus is notable, given the widely recognised host-pathogen association between these species and evidence for L. interrogans infection in R. norvegicus in Cape Town. It is likely that environmental conditions (cold, dry winters) in Johannesburg may limit the transmission of L. interrogans. Spatial heterogeneity in prevalence suggest that local factors, such as land use, influence disease risk in the metropole. Conclusions In South Africa, as in other African countries, leptospirosis is likely underdiagnosed. The high prevalence of infection in urban rodents in Johannesburg suggest that further work is urgently needed to understand the potential public health risk posed by this neglected zoonotic pathogen.

Preventing bacterial diseases in dairy cattle

2021 ◽  
pp. 395-456
Author(s):  
Sharif S. Aly ◽  
◽  
Sarah M. Depenbrock ◽  
Keyword(s):  
Risk Factors ◽  
Environmental Factors ◽  
Disease Prevention ◽  
Dairy Cattle ◽  
Disease Risk ◽  
Risk Identification ◽  
Bacterial Disease ◽  
Host Environment ◽  
Bacterial Diseases ◽  
Host Pathogen

A paradigm shift in the management of bacterial diseases of food animals is needed; a shift from pharmacologic interventions to disease risk identification and mitigation. The interaction between disease and its risk factors follows the disease triangle, a conceptual model that incorporates host, pathogen, and environmental factors as a tool to understand different aspects that influence disease. A sustainable approach to bacterial disease mitigation in production settings includes a comprehensive assessment of host, pathogen, and environmental factors of disease to build a prevention platform for multiple syndromes of bacterial disease in cattle. Using bovine respiratory disease as a model, the current chapter will focus on the state of the art of disease prevention in dairy cattle, and investigations into interactions between the host, environment and pathogen which can provide robust information on which to build a prevention platform for multiple syndromes of bacterial disease in cattle.

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