@article{fdi:010082676,
  title = {{A} field test of the dilution effect hypothesis in four avian multi-host pathogens},
  author = {{F}erraguti, {M}. and {M}artinez-de la {P}uente, {J}. {M}. and {J}imenez-{C}lavero, {M}. {A}. and {L}lorente, {F}. and {R}oiz, {D}avid and {R}uiz, {S}. and {S}origuer, {R}. and {F}iguerola, {J}.},
  editor = {},
  language = {{ENG}},
  abstract = {{A}uthor's summary {T}he {D}ilution {E}ffect {H}ypothesis ({DEH}) postulates that biodiversity can reduce disease epidemics because more diverse communities harbour a lower fraction of competent hosts, which thus reduces pathogen prevalence. {H}ere, we tested {DEH} by using field information from 45 populations in {SW} {S}pain on the prevalence of four vector-borne pathogens and considered both the potential role of the vertebrate community and mosquito vectors. {W}e determined the prevalence of {P}lasmodium, {H}aemoproteus, {L}eucocytozoon and antibodies for the zoonotic {W}est {N}ile virus in wild house sparrows. {C}ontrary to the predictions of {DEH}, our results do not support the general protective ability of biodiversity to reduce the prevalence of these four pathogens. {T}he {D}ilution {E}ffect {H}ypothesis ({DEH}) argues that greater biodiversity lowers the risk of disease and reduces the rates of pathogen transmission since more diverse communities harbour fewer competent hosts for any given pathogen, thereby reducing host exposure to the pathogen. {DEH} is expected to operate most intensely in vector-borne pathogens and when species-rich communities are not associated with increased host density. {O}verall, dilution will occur if greater species diversity leads to a lower contact rate between infected vectors and susceptible hosts, and between infected hosts and susceptible vectors. {F}ield-based tests simultaneously analysing the prevalence of several multi-host pathogens in relation to host and vector diversity are required to validate {DEH}. {W}e tested the relationship between the prevalence in house sparrows ({P}asser domesticus) of four vector-borne pathogens-three avian haemosporidians (including the avian malaria parasite {P}lasmodium and the malaria-like parasites {H}aemoproteus and {L}eucocytozoon) and {W}est {N}ile virus ({WNV})-and vertebrate diversity. {B}irds were sampled at 45 localities in {SW} {S}pain for which extensive data on vector (mosquitoes) and vertebrate communities exist. {V}ertebrate censuses were conducted to quantify avian and mammal density, species richness and evenness. {C}ontrary to the predictions of {DEH}, {WNV} seroprevalence and haemosporidian prevalence were not negatively associated with either vertebrate species richness or evenness. {I}ndeed, the opposite pattern was found, with positive relationships between avian species richness and {WNV} seroprevalence, and {L}eucocytozoon prevalence being detected. {W}hen vector (mosquito) richness and evenness were incorporated into the models, all the previous associations between {WNV} prevalence and the vertebrate community variables remained unchanged. {N}o significant association was found for {P}lasmodium prevalence and vertebrate community variables in any of the models tested. {D}espite the studied system having several characteristics that should favour the dilution effect (i.e., vector-borne pathogens, an area where vector and host densities are unrelated, and where host richness is not associated with an increase in host density), none of the relationships between host species diversity and species richness, and pathogen prevalence supported {DEH} and, in fact, amplification was found for three of the four pathogens tested. {C}onsequently, the range of pathogens and communities studied needs to be broadened if we are to understand the ecological factors that favour dilution and how often these conditions occur in nature.},
  keywords = {{ESPAGNE} ; {ZONE} {MEDITERRANEENNE}},
  booktitle = {},
  journal = {{PL}o{S} {P}athogens},
  volume = {17},
  numero = {6},
  pages = {e1009637 [21 p.]},
  ISSN = {1553-7366},
  year = {2021},
  DOI = {10.1371/journal.ppat.1009637},
  URL = {https://www.documentation.ird.fr/hor/fdi:010082676},
}