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Disease spillover can have dramatic consequences in multispecies systems, potentially leading to the emergence of zoonoses. To better understand disease emergence patterns, an approach encompassing species relatedness metrics is needed. We show that integrating phylogenetic information in disease ecology is still lagging, and we highlight potential solutions to solve this problem. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sympatric hairworms follow different transmission routes through host communities. • Some dead-end hosts represent important population sinks for hairworms. • Some host species can simultaneously contribute and hinder the hairworm life cycle. • Certain key host species can alter the flow of parasites in a community. • Relative host community composition can effectively impact parasite transmission. Community composition, including the relative density of each host species, plays a vital role in the transmission of parasites or disease in freshwater ecosystems. Whereas some host species can effectively transmit parasites, others can act as dead ends (non-viable transmission routes), accumulating large numbers of parasites throughout their life, thus becoming important sinks for parasite populations. Although population sinks have been identified in certain host-parasite systems, robust field estimates of the proportions of parasites that are lost to these hosts are lacking. Here, we quantified the distribution of encysted larval hairworms (phylum Nematomorpha), common parasites in lotic ecosystems, in two subalpine stream communities of New Zealand. With parasite and host population densities calculated per m2, we identified which host species most likely contributed to the transmission of three sympatric hairworm morphotypes identified in both streams, and which species acted as population sinks. We also tested for seasonal patterns and peaks in the abundance of each morphotype in the two communities over the sampling season. Finally, we tested whether hosts emerging from the streams had comparable abundances of hairworm morphotypes throughout the sampling period. For each morphotype, different key sets of host species harboured more hairworms on average (abundance) than others, depending on the stream. For one morphotype in particular, two species of hosts were found to be important population sinks that inhibited over a third of these parasites from completing their life cycle. We also observed a clear peak in abundance for another hairworm morphotype during summer. Our data suggest that hosts emerging from the streams matched their aquatic counterparts with respect to hairworm abundance, indicating no infection-dependent reduction in emergence success. Our findings suggest that, depending on relative community composition, sympatric parasites follow different host transmission pathways, some of which lead to dead ends that potentially impact overall infection dynamics. In turn, this information can help us understand the spread or emergence of disease in both freshwater and terrestrial environments, since hairworms infect terrestrial arthropods to complete their life cycle. [ABSTRACT FROM AUTHOR]

Big data have become readily available to explore patterns in large-scale disease ecology. However, the rate at which these public databases are exploited remains unknown. We highlight trends in big data usage in disease ecology during the past decade and encourage researchers to integrate big data into their study framework. [ABSTRACT FROM AUTHOR]

Host organisms show altered phenotypic reactions when parasitised, some of which result from adaptive host manipulation, a phenomenon that has long been debated. Here, we provide an overview and discuss the rationale in distinguishing adaptive versus nonadaptive host behavioural manipulation. We discuss Poulin's criteria of adaptive host behavioural manipulation within the context of Tinbergen's four questions of ethology, while highlighting the importance of both the proximate and evolutionary explanations of such traits. We also provide guidelines for future studies exploring the adaptiveness of host behavioural manipulation. Through this article, we seek to encourage researchers to consider both the proximate and ultimate causes of host behavioural manipulation to infer on the adaptiveness of such traits. Host manipulation has evolved as a primary life history strategy in all major parasitic lineages, and its adaptive significance is well established. Although adaptiveness is an evolutionary concept, the complexity of analysing the evolutionary parameters of a manipulative trait has given rise to an ongoing debate on the criteria of adaptive host manipulation. The importance of both proximate and ultimate mechanisms for inferring the adaptiveness of host manipulation is discussed by reviewing Poulin's criteria considering Tinbergen's four questions of ethology. There are important parallels between Tinbergen's four questions and Poulin's criteria of adaptive host behavioural manipulation, from an ethological perspective. Their one-to-one analysis provides deeper insights into the importance of both proximate and ultimate mechanisms of adaptive host behavioural manipulation. [ABSTRACT FROM AUTHOR]

Digital data (internet queries, page views, social media posts, images) are accumulating online at increasing rates. Tools for compiling these data and extracting their metadata are now readily available. We highlight the possibilities and limitations of internet data to reveal patterns in host–parasite interactions and encourage parasitologists to embrace iParasitology. [ABSTRACT FROM AUTHOR]

Parasites are important drivers of ecosystem functions and play a key role in the maintenance of ecosystem health. However, parasites may be threatened by host conservation, as well as by host extinction. Captive management is of increasing importance for conserving threatened host species, but captivity represents a drastic environmental change that may in turn threaten parasites. To address this concern, we examined how host captivity affects the odds of parasite infection and identified which parasite life-history traits (particularly modes of transmission) are the strongest predictors of parasite decline. Data were collated from 45 studies examining parasite prevalence in both captive and free-range host populations across a total of 55 host and 158 parasite species. We performed meta-analyses of these studies and found that overall, the odds of infection by parasites were not different between host populations in captive and free-range environments. However, the odds of infection by helminths were lower in captivity. Parasites with indirect life cycles, especially helminths with complex life cycles and vector-borne protozoa, also had lower odds of infecting hosts in captivity. Finally, parasites transmitted through the environment with direct life cycles, particularly environmentally-transmitted helminths, had lower odds of infecting hosts in captivity. Parasite losses in captivity are likely caused by the use of antiparasitic drugs, and the biotic and abiotic differences between captive and free-range environments. If the goals of activities such as captive breeding are to re-establish self-sustaining ecosystems, then conservation efforts need to include both hosts and their parasites in captive management programs. • No overall difference in odds of infection in captive vs free range populations. • Helminths were less common in captive hosts, but no difference for protozoa or bacteria. • Environmentally transmitted parasites were less common in captive environments. • Odds of infection by helminths with complex lifecycles were lower in captivity. • Infection by vector-born protozoa was less likely in captive environments. [ABSTRACT FROM AUTHOR]