Mosquito diversity and dog heartworm prevalence in suburban areas

Abstract

Background: Urbanization is occurring rapidly on a global scale and is altering mosquito communities, creating assemblages that are characteristically less diverse. Despite high rates of urbanization and ample examples of vector-borne diseases transmitted by multiple species, the effects of urbanization-driven mosquito diversity losses on disease transmission has not been well explored. We investigated this question using the dog heartworm, a filarial parasite vectored by numerous mosquito species. Methods: We trapped host-seeking mosquitoes in undeveloped areas and neighborhoods of different ages in Wake County, North Carolina, USA, analyzing captured mosquitoes for heartworm DNA. We compared within-mosquito heartworm infection across land-use types by Kruskal-Wallis and likelihood ratio tests. Using zip code level data acquired from dogs in a local shelter, we performed linear regressions of within-host heartworm prevalence by within-mosquito heartworm prevalence as well as by three mosquito diversity measures. We also determined the best predictor of host-level prevalence among models including within-mosquito infection, mosquito diversity and abundance, and socioeconomic status as variables. Results: Suburban areas had lower within-mosquito heartworm prevalence and lower likelihood of heartwormpositive mosquitoes than did undeveloped field sites, although no differences were seen between suburban and undeveloped wooded sites. No relationships were noted between within-mosquito and within-host heartworm prevalence. However, mosquito diversity metrics were positively correlated with host heartworm prevalence. Model selection revealed within-host prevalence was best predicted by a positive relationship with mosquito Shannon-Wiener diversity and a negative relationship with household income. Conclusions: Our results demonstrate that decreases in mosquito diversity due to urbanization alter vector-borne disease risk. With regard to dog heartworm disease, this loss of mosquito diversity is associated with decreased heartworm prevalence within both the vector and the host. Although the response is likely different for diseases transmitted by one or few species, mosquito diversity losses leading to decreased transmission could be generalizable to other pathogens with multiple vectors. This study contributes to better understanding of the effects of urbanization and the role of vector diversity in multi-vectored pathosystems.

Increased mosquito abundance and species richness in Connecticut, United States 2001–2019

“…Our correlations of mosquito collections and land cover support previous short-term research on mosquito communities [13][14][15][16][17][18] : after accounting for surveillance effort, richness and evenness were highest in sites with a greater prevalence of forested land cover and lowest in sites with a greater prevalence of land cover associated with human developments. This trend in richness was further evident in our GLMMs of collections by latitudinal www.nature.com/scientificreports/ coordinate (which also reflect the dominant land cover gradient of urban to forested in CT).…”

“…This could be an effect of the dominant gradient between urban-forested habitats in CT and the associated patterns detected between land cover and community composition metrics, with forested environments more prevalent in the eastern and northern portion of CT. Importantly, each metric measures a different aspect of community assembly, yet in the context of mosquito-borne pathogens, species richness is most often examined in relation to patterns of pathogen prevalence/incidence 17,18,29,36 . Further research is needed to determine the utility of measuring species evenness in relation to pathogen transmission.…”

“…There is some research that explores how mosquito communities are changing due to landscape-level dynamics. Previous studies on mosquito community structure have shown reductions in mosquito species richness and increases in the dominance of vectors of public health importance along forested to urban gradients 13 , simplification of mosquito community structure in homogenized landscapes 14 , changes in human risk of mosquito-borne pathogens linked to habitat disturbances 15,16 , and in some instances, increased mosquito species richness was associated with increased pathogen prevalence 17,18 . Globalization has also led to the introduction and establishment of mosquito species (and mosquito-borne pathogens) outside their evolutionary origins 19,20 .…”

Optimizing the feeding frequency to maximize the production of sterile males in tsetse mass-rearing colonies

“…gambiensis is reared but not massively as that of IBD, 3 days feeding per week is used with acceptable production [ 12 ]. However, the using of the same 3 days feeding per week for the same tsetse species at the IBD and at the CIRDES facilities in Bobo-Dioulasso, Burkina Faso [ 35 ] and for G . pallidipes at the Ethiopian Tsetse Eradication Project (STEP) facility [ 36 ], doesn’t allow to reach the objective of production.…”

“…p . gambiensis [ 35 ] and an increasing from 3 to 5 meals per pregnancy cycle of the STEP mass rearing colony of G . pallidipes [ 36 ] had been demonstrated.…”