A retroviral survey of endangered Eurasian lynx (Lynx lynx) from Croatia

Abstract

The feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) may cause persistent, lifelong and lethal infections in domestic and wild felids worldwide. FIV has been confirmed in most Felidae species, while FeLV infection is rare among non-domestic cats. The view that retroviruses are pathogenic in domestic cats but not in other free-ranging felid species was disproved by recent findings of retroviral pathology in several wild felids. The epidemiology of retroviral infections in felids in Croatia was only investigated in urban domestic cats, while there are no data for wild cat species. As the reintroduced Dinaric lynx (Lynx lynx) population suffers from low genetic diversity, which reduces their ability to adapt to new viral outbreaks, the health status of this lynx population is of particular concern. Two different commercial immunochromatographic assays were used for qualitative detection of FIV antibodies and FeLV antigens, while PCR was used for amplification of proviral gag and env genes in Eurasian lynx blood samples. All the 17 Eurasian lynx samples collected between 2001 and 2019 tested negative in both immunochromatographic and molecular tests. Even though our sample size was rather small, considering the fact that the population size of lynx in Croatia is estimated at 40 - 60 animals, our results can be considered representative for the population’s health status. Also, data about retroviral prevalence in Eurasian lynxes are scarce, so any new findings are very valuable.

Insights into subspecies classification and conservation priorities of Central Asian lynx populations revealed by morphometric and genetic analyses

“…The coronal suture was open in juveniles, partially closed in subadults, and fully closed in older adults. The sagittal crest in males of the subadult group was also comparably not developed, which was a characteristic of female adult specimens used for analysis 50 , 56 . Sexual dimorphism in the cranial structure became apparent through the progressive formation of ridges over time (see Supplementary Fig.…”

“…These age-related alterations aligned with patterns observed in other species within the same genus, where there was a relative augmentation in the facial region of the skull alongside the emergence of postorbital compression 5 . In adult males, sagittal and occipital crests develop 50 , and the coronal suture is closed in both males and females. Based on these age criteria, we assigned 9 specimens to the juvenile group, 13 to the subadult group (up to 2 years for females and 3 years for males 5 ), and 32 to the adult group.…”

Mandible Size and Shape of the Red Fox (Vulpes vulpes) and Golden Jackal (Canis aureus)

“…Our study revealed a significant difference between the total length of the fox (102.1 ± 4.8 mm) and jackal (117.7 ± 2.4 mm) mandibles, but this was similar to previous studies. Also, the total height of the vertical ramus was reported in two fox species as 3.7 ± 0.1 cm and 3.2 ± 0.2 cm (Munkhzull et al, 2018) in the golden jackal as 6.0 ± 0.58 cm (Monfared, 2013), in the lynx as 38.92 ± 1.63 mm, 44.1 ± 3.2 mm, (Gomerčić et al, 2010;Dayan et al, 2017) and in the wolf as 76.3 ± 3.8 mm (Okarma and Buchalczyk, 1993). The present study revealed similar values as in foxes from Mongolia (35.6 ± 2.2 mm), while the total height for the jackal was 42.6 ± 1.4 mm, which was significantly smaller compared with the study of jackals from Iran.…”

“…2019), in golden jackals 11.2 ± 3.46 cm according to Monfared (2013). In other carnivores such as the lynx, the total length of the mandible was 102.6±5.2 mm according to Gomerčić (2010), 93.45 ± 2.98 mm according to Dayan et al (2017) and in the wolf 190.4 ± 7.7 mm according to Okarma and Buchalczyk (1993). Our study revealed a significant difference between the total length of the fox (102.1 ± 4.8 mm) and jackal (117.7 ± 2.4 mm) mandibles, but this was similar to previous studies.…”

“…Cranial morphometry is crucial for taxonomy and has a major impact on the management and maintenance of the species. Several studies have been conducted regarding the craniometrics of carnivores, including dog (Onar, 1999;Ilgun et al, 2021), wolf (Okarma and Buchalczyk, 1993;Milenković et al, 2010;Khosravi et al, 2012;Gürbüz et al, 2020), fox (Gomes and Valente, 2016;Munkhzull et al, 2018;Magalhães et al, 2019), golden jackal (Monfared, 2013;Rezić et al, 2017) and lynx (Gomerčić et al, 2010;Dayan et al, 2017). Most of these studies include the mandible as the lower part of the facial skeleton.…”