Gastrointestinal parasite infestation in the alpine mountain hare (Lepus timidus varronis): Are abiotic environmental factors such as elevation, temperature and precipitation affecting prevalence of parasite species?

Morphological and molecular analysis of Aggregata aspera n. sp. (Apicomplexa: Aggregatidae) in Amphioctopus ovulum and Amphioctopus marginatus (Mollusca: Cephalopoda) from the Western Pacific Ocean

Aggregata Frenzel, 1885 (Apicomplexa) are dangerous protozoan parasites that cause malabsorption syndrome in wild and reared cephalopod species, resulting in significant economic loss to fishery and aquaculture industries. The new parasitic species, Aggregata aspera n. sp., in the digestive tract of Amphioctopus ovulum and Amphioctopus marginatus from an area in the Western Pacific Ocean was identified, it is the second two-host parasite species of Aggregata. Mature oocysts and sporocysts were spherical to ovoid in shape. Sporulated oocysts were 380.6-1,158.4 μm in length and 284.0-1,090.6 μm in width. The mature sporocysts were 16.2-18.3 μm in length and 15.7-17.6 μm in width, with irregular protuberances on the lateral wall of the sporocysts. Sporozoites within mature sporocysts were curled in shape and measured 13.0-17.0 μm in length and 1.6-2.4 μm in width. Each sporocyst contained 12-16 sporozoites. Phylogenetic tree analysis, based on 18S rRNA gene partial sequences, indicated that Ag. aspera forms a monophyletic cluster within the genus Aggregata and has a sister relationship with Ag. sinensis. These findings will provide the theoretical basis for the histopathology and diagnosis of coccidiosis in cephalopods.

A tale of two nematodes: Climate mediates mustelid infection by nematodes across the geographical range

Parasites have the potential to negatively affect host populations, if infection intensity is high. For parasites in which part of life cycle takes place outside the host, host infection intensity is likely affected by climate condition. Therefore, the parasite's impact on the host populations could be related to climatic conditions and may be altered with climate change. The aim of our study was to analyse the prevalence and infection intensity of two nematodes (Aonchotheca putorii and Molineus patens) from the Northern Hemisphere in relation to variations in climatic conditions. We reviewed 54 published studies on the occurrence of these two nematode species in 7 mustelid hosts. For A. putorii, infection parameters were higher when the stomach was included in the analyses compared to M. patens. The seasonality of precipitation influenced the prevalence the most, and the mean temperature of the warmest quarter had the strongest influence on infection intensity. The predicted prevalence of M. patens increased with increasing seasonal variation in precipitation, while the prevalence of A. putorii decreased. The predicted infection intensity of M. patens decreased with increasing precipitation seasonality, whereas the intensity of A. putorii infection did not change much. A. putorii infection intensity significantly decreased with increasing mean temperature of the warmest quarter, while the infection intensity of M. patens was not significantly related to this variable. Prevalence and infection intensity varied over the geographic range for both parasites, broadly with higher levels in northern latitudes for A. putorii and in southern latitudes for M. patens. Our study highlights the differences between these two nematode species and shows that the severity of host infection by these parasites is complex and mediated by climatic conditions. The results suggest that current climate change may potentially modify susceptibility and exposure to parasitic infections in mustelids.

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Analyses of the infection intensity of two nematodes on seven mustelid species on a large geographical scale.

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Climate modulates the infection parameters of the studied nematodes.

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Climatic conditions have contrasting effects on the two nematode species.

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The different effect of climate on parasite infection intensity is related to differences in their life cycles.

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Climate change may modify parasite infections and parasite impacts on wild carnivores.

Plant-eating carnivores: Multispecies analysis on factors influencing the frequency of plant occurrence in obligate carnivores

Plant-eating behavior is one of the greatest mysteries in obligate carnivores. Despite unsuitable morphological and physiological traits for plant consumption, the presence of plants in scat or stomach contents has been reported in various carnivorous species. However, researchers' interpretations of this subject are varied, and knowledge about it is scarce, without any multispecies studies. This study assessed the extent of variation in the frequency of plant occurrence in scat and stomach contents, as well as its relationship with various factors in 24 felid species using data from 213 published articles. Since the frequency of plant occurrence has not always been reported, we created two-part models and estimated parameters in a Bayesian framework. We found a significant negative relationship between the frequency of plant occurrence and body mass. This may be because plant-eating behavior reduces the energy loss caused by parasites and increases the efficiency of energy intake, which has a greater importance in smaller animals that have relatively high metabolic rates. This exploratory study highlights the importance of considering plant consumption in dietary studies on carnivorous species to understand the adaptive significance of this behavior and the relationship between obligate carnivores and plants.