Correction: <i>Toxoplasma gondii</i> Infection in Alpine Red Deer (<i>Cervus elaphus</i>): Its Spread and Effects on Fertility

<p>Correction: <i>Toxoplasma gondii</i> Infection in Alpine Red Deer (<i>Cervus elaphus</i>): Its Spread and Effects on Fertility</p

Effect of Kidney Fat Index (KFI) on foetal development (in days).

<p>Dots represent observed values (rhombus: 2–3 year-old females, circles: 4–6 year-old females; triangles: >7 year-old females) while lines represent the values predicted by the selected model (light grey line: area 1; black line: area 2).</p

Effect of serological titres on foetal development (in days).

<p>Dots represent observed values (rhombus: 2–3 year-old females, circles: 4–6 year-old females; triangles: >7 year-old females); lines represent the values predicted by the selected model (light grey line: area 1; black line: area 2).</p

Representation of the two sampling areas (black continuous line), 1 and 2; dotted line: limits of Stelvio National Park.

<p>Reprinted from the Stelvio National Park Information System under a CC BY license, with permission from Stelvio National Park, original copyright 2015 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138472#pone.0138472.s005" target="_blank">S1 Text</a>).</p

Arthropod species infesting grey squirrels in Piedmont and Lombardy populations.

<p>N: number of host examined; n: number of infested hosts; p: prevalence; mI: mean intensity (no. parasites infested/hosts; when number of infested hosts <5, worm counts in italic).</p

Variation of <i>C. sciurorum</i> abundance by season (A) and host density (B).

<p>Mean abundance of <i>C. sciurorum</i> (sample size above standard error bars) varied during different seasons (p<0.0001) and at different host densities (p<0.0001). Squirrels trapped in spring were more infested than in autumn and winter (both sequential Bonferroni adjusted p<0.0001) and animals living in high-density sites were more infested then those living in medium- and low-density populations (both adjusted p<0.008).</p

Minimum selected model of the effects of host characteristics and environmental variables on parasite abundance (no. of parasites/host).

<p>Minimum selected model of the effects of host characteristics and environmental variables on parasite abundance (no. of parasites/host).</p

Most prevalent gastro-intestinal helminths and arthropods (excluding mites) parasitizing grey squirrels in North America.

<p>Only parasites that were recorded by more than one author and with maximum prevalence >5% are reported. Studies with sample size <50 hosts were excluded.</p

Supplementary information.

West Nile disease is a vector-borne disease caused by West Nile virus (WNV), involving mosquitoes as vectors and birds as maintenance hosts. Humans and other mammals can be infected via mosquito bites, developing symptoms ranging from mild fever to severe neurological infection. Due to the worldwide spread of WNV, human infection risk is high in several countries. Nevertheless, there are still several knowledge gaps regarding WNV dynamics. Several aspects of transmission taking place between birds and mosquitoes, such as the length of the infectious period in birds or mosquito biting rates, are still not fully understood, and precise quantitative estimates are still lacking for the European species involved. This lack of knowledge affects the precision of parameter values when modelling the infection, consequently resulting in a potential impairment of the reliability of model simulations and predictions and in a lack of the overall understanding of WNV spread. Further investigations are thus needed to better understand these aspects, but field studies, especially those involving several wild species, such as in the case of WNV, can be challenging. Thus, it becomes crucial to identify which transmission processes most influence the dynamics of WNV. In the present work, we propose a sensitivity analysis to investigate which of the selected epidemiological parameters of WNV have the largest impact on the spread of the infection. Based on a mathematical model simulating WNV spread into the Lombardy region (northern Italy), the basic reproduction number of the infection was estimated and used to quantify infection spread into mosquitoes and birds. Then, we quantified how variations in four epidemiological parameters representing the duration of the infectious period in birds, the mosquito biting rate on birds, and the competence and susceptibility to infection of different bird species might affect WNV transmission. Our study highlights that knowledge gaps in WNV epidemiology affect the precision in several parameters. Although all investigated parameters affected the spread of WNV and the modelling precision, the duration of the infectious period in birds and mosquito biting rate are the most impactful, pointing out the need of focusing future studies on a better estimate of these parameters at first. In addition, our study suggests that a WNV outbreak is very likely to occur in all areas with suitable temperatures, highlighting the wide area where WNV represents a serious risk for public health.</div

Variation of <i>S. robustus</i> abundance by host density.

<p>Mean abundance of <i>S. robustus</i> (sample size above standard error bars) varied with density of hosts in the site (p<0.0001). Squirrels living in high-density sites were more infested than individuals living in medium- and low-density sites (both sequential Bonferroni adjusted p<0.0001) and squirrels living in medium-density sites were more infested than in low-density sites (adjusted p = 0.0008).</p