scholarly journals Predicting missing links in global host-parasite networks

2020 ◽  
Author(s):  
Maxwell J. Farrell ◽  
Mohamad Elmasri ◽  
David Stephens ◽  
T. Jonathan Davies

Parasites that infect multiple species cause major health burdens globally, but for many, the full suite of susceptible hosts is unknown. Proactive disease surveillance involves gathering host-parasite association data, predicting missing links, and targeting efforts towards the most likely undocumented interactions. Using the largest global network of mammal host-parasite interactions amalgamated to date (>29,000 interactions), we predict undocumented links and conduct targeted literature searches. We find evidence for many of the top “missing” links, including parasites of humans, domesticated animals, and endangered wildlife, and identify regions such as tropical and central America as likely hotspots of undocumented associations. This approach of iterated prediction and targeted surveillance can efficiently guide the collection of host-parasite interaction data critical for developing broad-scale theories in disease ecology and evolution, help to identify previously undocumented hosts, and inform predictions of future host-parasite interactions.

2021 ◽  
Vol 376 (1837) ◽  
pp. 20200360 ◽  
Author(s):  
Ignacio Morales-Castilla ◽  
Paula Pappalardo ◽  
Maxwell J. Farrell ◽  
A. Alonso Aguirre ◽  
Shan Huang ◽  
...  

Species are shifting their distributions in response to climate change. This geographic reshuffling may result in novel co-occurrences among species, which could lead to unseen biotic interactions, including the exchange of parasites between previously isolated hosts. Identifying potential new host–parasite interactions would improve forecasting of disease emergence and inform proactive disease surveillance. However, accurate predictions of future cross-species disease transmission have been hampered by the lack of a generalized approach and data availability. Here, we propose a framework to predict novel host–parasite interactions based on a combination of niche modelling of future host distributions and parasite sharing models. Using the North American ungulates as a proof of concept, we show this approach has high cross-validation accuracy in over 85% of modelled parasites and find that more than 34% of the host–parasite associations forecasted by our models have already been recorded in the literature. We discuss potential sources of uncertainty and bias that may affect our results and similar forecasting approaches, and propose pathways to generate increasingly accurate predictions. Our results indicate that forecasting parasite sharing in response to shifts in host geographic distributions allow for the identification of regions and taxa most susceptible to emergent pathogens under climate change. This article is part of the theme issue ‘Infectious disease macroecology: parasite diversity and dynamics across the globe’.


2010 ◽  
Vol 56 (3-4) ◽  
pp. 313-324 ◽  
Author(s):  
Brian F. Allan ◽  
Theodore S. Varns ◽  
Jonathan M. Chase

Nonconsumptive effects of predators on their prey are extensive and diverse, with significant consequences for community structure and ecosystem function. However, despite many theoretical similarities between predator-prey and host-parasite interactions, nonconsumptive effects of parasites on their hosts remain poorly understood. Further, such effects may be of consequence to human and wildlife health, when host-parasite interactions involve hematophagous arthropods that vector infectious diseases. We used giving-up density estimation techniques to measure the response of white-tailed deer(Odocoileus virginianus)to the risk of parasitism by lone star ticks(Amblyomma americanum), an important vector of several infectious diseases in the southeastern United States. We also deployed carnivore scent stations to estimate activity levels of potential deer predators, conducted deer dung count surveys to control for effects of deer abundance, and controlled for topographic aspect, a primary determinant of vegetative biomass and community composition. We found a significant, positive correlation between giving-up densities in deer and the densities ofA. americanum, but no effect of canid predators, deer abundance, or topographic aspect. Our results are consistent with the few other empirical examples that demonstrate nonconsumptive effects of parasites on their hosts. Considering that host-parasite interactions have enormous potential to influence the prevalence of vector-borne diseases that affect human health, incorporating indirect effects of parasites on their hosts into infectious disease ecology may be necessary to effectively mitigate disease risk.


2015 ◽  
Vol 282 (1817) ◽  
pp. 20151993 ◽  
Author(s):  
Leiling Tao ◽  
Camden D. Gowler ◽  
Aamina Ahmad ◽  
Mark D. Hunter ◽  
Jacobus C. de Roode

Host–parasite interactions are subject to strong trait-mediated indirect effects from other species. However, it remains unexplored whether such indirect effects may occur across soil boundaries and connect spatially isolated organisms. Here, we demonstrate that, by changing plant (milkweed Asclepias sp.) traits, arbuscular mycorrhizal fungi (AMF) significantly affect interactions between a herbivore (the monarch butterfly Danaus plexippus ) and its protozoan parasite ( Ophryocystis elektroscirrha ), which represents an interaction across four biological kingdoms. In our experiment, AMF affected parasite virulence, host resistance and host tolerance to the parasite. These effects were dependent on both the density of AMF and the identity of milkweed species: AMF indirectly increased disease in monarchs reared on some species, while alleviating disease in monarchs reared on other species. The species-specificity was driven largely by the effects of AMF on both plant primary (phosphorus) and secondary (cardenolides; toxins in milkweeds) traits. Our study demonstrates that trait-mediated indirect effects in disease ecology are extensive, such that below-ground interactions between AMF and plant roots can alter host–parasite interactions above ground. In general, soil biota may play an underappreciated role in the ecology of many terrestrial host–parasite systems.


2011 ◽  
Vol 41 (9) ◽  
pp. 925-933 ◽  
Author(s):  
James A. Cotton ◽  
Jennifer K. Beatty ◽  
Andre G. Buret

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Lenka Ulrychová ◽  
Pavel Ostašov ◽  
Marta Chanová ◽  
Michael Mareš ◽  
Martin Horn ◽  
...  

Abstract Background The blood flukes of genus Schistosoma are the causative agent of schistosomiasis, a parasitic disease that infects more than 200 million people worldwide. Proteases of schistosomes are involved in critical steps of host–parasite interactions and are promising therapeutic targets. We recently identified and characterized a group of S1 family Schistosoma mansoni serine proteases, including SmSP1 to SmSP5. Expression levels of some SmSPs in S. mansoni are low, and by standard genome sequencing technologies they are marginally detectable at the method threshold levels. Here, we report their spatial gene expression patterns in adult S. mansoni by the high-sensitivity localization assay. Methodology Highly sensitive fluorescence in situ RNA hybridization (FISH) was modified and used for the localization of mRNAs encoding individual SmSP proteases (including low-expressed SmSPs) in tissues of adult worms. High sensitivity was obtained due to specifically prepared tissue and probes in combination with the employment of a signal amplification approach. The assay method was validated by detecting the expression patterns of a set of relevant reference genes including SmCB1, SmPOP, SmTSP-2, and Sm29 with localization formerly determined by other techniques. Results FISH analysis revealed interesting expression patterns of SmSPs distributed in multiple tissues of S. mansoni adults. The expression patterns of individual SmSPs were distinct but in part overlapping and were consistent with existing transcriptome sequencing data. The exception were genes with significantly low expression, which were also localized in tissues where they had not previously been detected by RNA sequencing methods. In general, SmSPs were found in various tissues including reproductive organs, parenchymal cells, esophagus, and the tegumental surface. Conclusions The FISH-based assay provided spatial information about the expression of five SmSPs in adult S. mansoni females and males. This highly sensitive method allowed visualization of low-abundantly expressed genes that are below the detection limits of standard in situ hybridization or by RNA sequencing. Thus, this technical approach turned out to be suitable for sensitive localization studies and may also be applicable for other trematodes. The results suggest that SmSPs may play roles in diverse processes of the parasite. Certain SmSPs expressed at the surface may be involved in host–parasite interactions. Graphic abstract


2021 ◽  
Vol 10 (2) ◽  
pp. 205
Author(s):  
Lúcio Lara Santos ◽  
Júlio Santos ◽  
Maria João Gouveia ◽  
Carina Bernardo ◽  
Carlos Lopes ◽  
...  

Schistosomiasis is the most important helminthiasis worldwide in terms of morbidity and mortality. Most of the infections occurs in Africa, which about two thirds are caused by Schistosoma haematobium. The infection with S. haematobium is considered carcinogenic leading to squamous cell carcinoma (SCC) and urothelial carcinoma of the urinary bladder. Additionally, it is responsible for female genital schistosomiasis leading to infertility and higher risk of human immunodeficiency virus (HIV) transmission. Remarkably, a recent outbreak in Corsica (France) drew attention to its potential re-mergence in Southern Europe. Thus far, little is known related to host-parasite interactions that trigger carcinogenesis. However, recent studies have opened new avenues to understand mechanisms on how the parasite infection can lead cancer and other associated pathologies. Here, we present a historical perspective of schistosomiasis, and review the infection-associated pathologies and studies on host–parasite interactions that unveil tentative mechanisms underlying schistosomiasis-associated carcinogenesis.


2021 ◽  
Vol 37 (5) ◽  
pp. 445-455
Author(s):  
Rogini Runghen ◽  
Robert Poulin ◽  
Clara Monlleó-Borrull ◽  
Cristina Llopis-Belenguer

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