Eimeria species

Jarquín-Díaz, Víctor Hugo, Balard, Alice, Jost, Jenny, Kraft, Julia, Dikmen, Mert Naci, Kvičerová, Jana & Heitlinger, Emanuel, 2019, Detection and quantification of house mouse Eimeria at the species level - Challenges and solutions for the assessment of coccidia in wildlife, International Journal for Parasitology: Parasites and Wildlife 10, pp. 29-40 : 33-35

3.6. Prevalence of the different Eimeria species

Genotyping amplification and sequencing with either 18S or COI primers (or both) was possible for samples in which infections had been detected (n = 82) ( Fig. 1B ). Both COI and 18S genotyping PCRs hence support detection by flotation and diagnostic PCRs in this subset of samples. Furthermore amplification of both or either one maker was fully sufficient to assign the isolate to an Eimeria species ( Fig. 2 ), allowing us to resolve prevalence on the species level.

These corrections and controls allow us to determine prevalence at the species level: E. ferrisi was identified at a higher prevalence of 16.7% (63/378, 95%CI = 13.2–20.7) in comparison to E. falciformis (16/378, 4.2% [95%CI = 2.6–6.8]) and E. vermiformis (7/378, 1.9%

[0.9–3.8]).

Considering prevalence at the level of farms, E. ferrisi was detected in 29.2% (28/96, 95%CI = 20.7–39.0), E. falciformis in 12.5% (12/96, 95%CI = 7.1–20.7) and E. vermiformis in 7.3% (7/96, 95%CI = 3.5–14.4) of sampled localities. 25 (of in total 96) farms, had mice with single Eimeria species detected, and 10 had more than one species detected. In all cases E. ferrisi was detected (5 farms with E. ferrisi – E. falciformis , 3 farms with E. ferrisi – E. vermiformis combination, and 2 farms with the three species). Mice presenting double

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Eimeria pitted body parenthesis in from characteristics Wall Smooth Smooth Smooth Smooth Smooth Lightly Refractile Present Present Present Present Present Present with micrometers ranges oocysts.

morphometrical Oocysts Shape Ellipsoidal / Spherical Spherical / Ovoid /Ellipsoidal Spherical Subspherical / Ellipsoidal Ellipsoidal / Spherical / Spherical Ellipsoidal Sporocysts Residuum Present Present Present Present Absent / Present Present are means in of the than % 80 evident. and more 1 Table Morphological Species E falciformis . falciformis E. E. ferrisi . ferrisi E vermiformis . E. E vermiformis Species. E falciformis falciformis E.. ferrisi E. E ferrisi . vermiformis E vermiformis . E a Measurements b in Observed c Present but not infections were caught at farms at which infections with the both Eimeria species was found in other mice independently.

We used the number of mice caught per farm as a proxy for population density, assuming roughly equal trapping effort at all localities. We then question whether population density affects prevalence by testing differences in the likelihood of a mouse individual to be infected dependent on that population density. We detect that the likelihood of infection is significantly increased for both E. ferrisi and for E. falciformis (logistic regression, p <0.05; Table 3). Infection with E. falciformis got more likely by 19%, infection with E. ferrisi by 14% with each mouse caught at the same locality. We also included the detection of other Eimeria species in the model for each species and did not find a significant influence (p> 0.05) on likelihood of infection.

Figures

Fig. 1. Geographical localization of house mice (Mus musculus) collected for this study and comparison of diagnostic methods for Eimeria. A) Localization from the 378 mice included in the present study, colors indicate the Eimeria species identified for each. B) Venn diagram showing the overlap between detection methods and successful genotyping identification of the isolates. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 2. Phylogenetic trees based on 18S rRNA and COI sequences. Sequences of 18S A) and COI B) were used to infer the molecular identification of wild-derived isolates of Eimeria. In both phylogenies, our isolates clustered in three groups one close to E. falciformis (red), other close to E. ferrisi (green) and finally one to E. vermiformis (yellow). Numbers in the branches represent the Bayesian posterior probability and the non-parametric bootstrap value. In bold are indicate the reference sequences for each species. CE and IL make reference to sequence derived from cecum or ileum tissue DNA, respectively. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)