Analysis of large new South African dataset using two host-specificity indices shows generalism in both adult and larval ticks of mammals

SUMMARYTicks and tick-borne pathogens can have considerable impacts on the health of livestock, wildlife and people. Knowledge of tick–host preferences is necessary for both tick and pathogen control. Ticks were historically considered as specialist parasites, but the range of sampled host species has been limited, infestation intensity has not been included in prior analyses, and phylogenetic distances between hosts have not been previously considered. We used a large dataset of 35 604 individual collections and two host-specificity indices to assess the specificity of 61 South African tick species, as well as distinctions between adult and juvenile ticks, for 95 mammalian hosts. When accounting for host phylogeny, most adult and juvenile ticks behaved as generalists, with juveniles being significantly more generalist than adults. When we included the intensity of tick infestation, ticks exhibited a wider diversity of specificity in all life stages. Our results show that ticks of mammals in South Africa tend to behave largely as generalists and that adult ticks are more host-specific. More generally, our analysis shows that the incorporation of life-stage differences, infestation intensity and phylogenetic distances between hosts, as well as the use of more than one specificity index, can all contribute to a deeper understanding of host–parasite interactions.

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The ghost of hosts past: impacts of host extinction on parasite specificity

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2020.0351 ◽

2021 ◽

Vol 376 (1837) ◽

pp. 20200351 ◽

Cited By ~ 4

Author(s):

Maxwell J. Farrell ◽

Andrew W. Park ◽

Clayton E. Cressler ◽

Tad Dallas ◽

Shan Huang ◽

...

Keyword(s):

Host Specificity ◽

Disease Ecology ◽

Parasite Species ◽

Biodiversity Loss ◽

Virulence Evolution ◽

Host Phylogeny ◽

Parasite Biodiversity ◽

Host Parasite ◽

The Impact ◽

Host Extinction

A growing body of research is focused on the extinction of parasite species in response to host endangerment and declines. Beyond the loss of parasite species richness, host extinction can impact apparent parasite host specificity, as measured by host richness or the phylogenetic distances among hosts. Such impacts on the distribution of parasites across the host phylogeny can have knock-on effects that may reshape the adaptation of both hosts and parasites, ultimately shifting the evolutionary landscape underlying the potential for emergence and the evolution of virulence across hosts. Here, we examine how the reshaping of host phylogenies through extinction may impact the host specificity of parasites, and offer examples from historical extinctions, present-day endangerment, and future projections of biodiversity loss. We suggest that an improved understanding of the impact of host extinction on contemporary host–parasite interactions may shed light on core aspects of disease ecology, including comparative studies of host specificity, virulence evolution in multi-host parasite systems, and future trajectories for host and parasite biodiversity. This article is part of the theme issue ‘Infectious disease macroecology: parasite diversity and dynamics across the globe’.

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The ghost of hosts past: impacts of host extinction on parasite specificity

10.32942/osf.io/euza8 ◽

2021 ◽

Author(s):

Maxwell Jenner Farrell ◽

Andrew Park ◽

Clay Cressler ◽

Tad Dallas ◽

Shan Huang ◽

...

Keyword(s):

Host Specificity ◽

Disease Ecology ◽

Parasite Species ◽

Biodiversity Loss ◽

Virulence Evolution ◽

Host Phylogeny ◽

Parasite Biodiversity ◽

Host Parasite ◽

The Impact ◽

Host Extinction

A growing body of research is focused on the extinction of parasite species in response to host endangerment and declines. Beyond the loss of parasite species richness, host extinction can impact apparent parasite host specificity, as measured by host richness or the phylogenetic distances among hosts. Such impacts on the distribution of parasites across the host phylogeny can have knock-on effects that may reshape the adaptation of both hosts and parasites, ultimately shifting the evolutionary landscape underlying the potential for emergence and the evolution of virulence across hosts. Here we examine how the reshaping of host phylogenies through extinction may impact the host specificity of parasites, and offer examples from historical extinctions, present-day endangerment, and future projections of biodiversity loss. We suggest that an improved understanding of the impact of host extinction on contemporary host-parasite interactions may shed light on core aspects of disease ecology, including comparative studies of host specificity, virulence evolution in multi-host parasite systems, and future trajectories for host and parasite biodiversity.

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Host community heterogeneity and the expression of host specificity in avian haemosporidia in the Western Cape, South Africa

Parasitology ◽

10.1017/s0031182018000665 ◽

2018 ◽

Vol 145 (14) ◽

pp. 1876-1883 ◽

Cited By ~ 3

Author(s):

Sharon M. Jones ◽

Graeme S. Cumming ◽

Jeffrey L. Peters

Keyword(s):

South Africa ◽

Host Specificity ◽

Parasite Prevalence ◽

Host Community ◽

Western Cape ◽

Community Heterogeneity ◽

Host Parasite Interactions ◽

Abundance And Diversity ◽

Animal Communities ◽

Host Parasite

AbstractSimilar patterns of parasite prevalence in animal communities may be driven by a range of different mechanisms. The influences of host heterogeneity and host–parasite interactions in host community assemblages are poorly understood. We sampled birds at 27 wetlands in South Africa to compare four hypotheses explaining how host community heterogeneity influences host specificity in avian haemosporidia communities: the host-neutral hypothesis, the super-spreader hypothesis, the host specialist hypothesis and the heterogeneity hypothesis. A total of 289 birds (29%) were infected with Plasmodium, Haemoproteus and/or Leucocytozoon lineages. Leucocytozoon was the most diverse and generalist parasite genus, and Plasmodium the most conservative. The host-neutral and host specialist hypotheses received the most support in explaining prevalence by lineage (Leucocytozoon) and genus (Plasmodium and Haemoproteus), respectively. We observed that haemosporidian prevalence was potentially amplified or reduced with variation in host and/or parasitic taxonomic levels of analysis. Our results show that Leucocytozoon host abundance and diversity was influential to parasite prevalence at varying taxonomic levels, particularly within heterogeneous host communities. Furthermore, we note that prevalent mechanisms of infection can potentially act as distinct roots for shaping communities of avian haemosporidia.

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Ecological Specificity of Parasites of Some Embiotocid Fishes

Journal of the Fisheries Research Board of Canada ◽

10.1139/f67-176 ◽

1967 ◽

Vol 24 (10) ◽

pp. 2161-2168 ◽

Cited By ~ 3

Author(s):

Hisao P. Arai

Keyword(s):

Host Specificity ◽

Ecological Factors ◽

The Family ◽

Host Phylogeny ◽

Parasite Evolution ◽

Ecological Specificity ◽

Host Parasite

An investigation of the relative roles of phylogenetic and ecological factors in determining host specificity at the intrafamilial level in fishes of the family Embiotocidae has been made. The results do not show indications that specificity is related to host phylogeny, i.e. parallel host–parasite evolution is not apparent. However, data are presented which strongly support the contention that specificity of parasites in Cymatogaster aggregata is determined by factors which are of an ecological nature.

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