Populations of the ticks Ixodes (Pholeoixodes) hexagonus and Ixodes (Pholeoixodes) canisuga infesting suburban foxes, Vulpes vulpes

Forensic findings in urban red fox mortality in the metropolitan area of Madrid, 2014-2022

The expanding presence of red foxes (Vulpes vulpes) in urban and suburban regions could potentially lead to increased instances of human aggression towards this species. We studied 10 deceased red foxes that were submitted by law enforcement agencies in the metropolitan area of Madrid in 2014-2022 because of suspected abuse. Forensic autopsies were performed to establish the cause and manner of death. In 4 of the 10 cases, the cause of death was deemed unnatural, involving blunt-force trauma (n = 2), asphyxia resulting from hanging (n = 1), and firearm injury (n = 1). Among the remaining cases, most had succumbed to natural causes (n = 4), often marked by severe emaciation and a high burden of parasites, primarily Sarcoptes scabiei. In 2 cases, death was undetermined given the poor preservation of the carcass. The growing prevalence of wildlife species in urban areas, particularly red foxes, may require forensic veterinary investigation of deaths potentially related to abuse.

Tick findings from subterranean environments in the Central German Uplands and Luxembourg reveal a predominance of male Ixodes hexagonus

Questing ticks are usually collected by flagging or dragging. Mostly exophilic tick species are caught, such as Ixodes ricinus, the most common tick in Central Europe. In the present study, ticks collected from underground environments in the Grand Duchy of Luxembourg and in the Central German Uplands (Federal States of Hesse, Bavaria, Thuringia, Baden-Wuerttemberg, Rhineland-Palatinate, Saarland and Northrhine-Westphalia) were investigated. Six tick species were revealed among the 396 analyzed specimens: Ixodes ariadnae, Ixodes canisuga, Ixodes hexagonus, I. ricinus, Ixodes trianguliceps, and Dermacentor marginatus. Adults and immatures of I. hexagonus dominated the findings (57% of all specimens), especially in shelters acting as potential resting places of main hosts. Ixodes canisuga and I. trianguliceps were for the first time recorded in Luxembourg, and one nymph of the bat tick I. ariadnae represents only the second report for Germany. Collecting ticks in subterranean environments turned out to be a useful approach to increase knowledge about the occurrence of relatively rare tick species, including those that spend most of their lifetime on their hosts, but detach in such environmental settings.

Ectoparasites of red foxes (Vulpes vulpes) with a particular focus on ticks in subcutaneous tissues

In the present study, we identified the ectoparasite communities of red foxes in three regions of Poland that encompassed two endemic regions for the occurrence of Dermacentor reticulatus, as well as a region that is free of this tick species ('gap' area). Our study sites were selected to enable the role of foxes as hosts for juvenile (nest dwelling) and adult (exophilic) D. reticulatus ticks to be determined, and to assess their contribution to the spread of this important vector of Babesia canis. We compared also ectoparasite communities between adult foxes with those of fox cubs. Finally, we carried out a systematic search for subcutaneous ticks determining their prevalence and abundance. In 2016-2018, 366 adult foxes and 25 live-trapped cubs were examined for ectoparasites. Ectoparasites were identified based on morphological features, PCR amplification and sequencing. The total prevalence of ectoparasites was higher in cubs (68%) than in adults (62.8%). In adults, 15 parasite species were recorded, including four tick species, seven flea species, scabies, and one Anopluran species each in the genera Felicola and Lipoptena. In cubs, six ectoparasite species were found, including Ixodes kaiseri, a species not found in adults. Although Ixodes ricinus and D. reticulatus were the dominant tick species on adult foxes, no D. reticulatus ticks were found on cubs. Subcutaneous ticks were common (38%) and abundant in all areas. Molecular analysis of subcutaneous nodules allowed the identification of 17 I. ricinus and five D. reticulatus. In conclusion, red foxes play a minor role as hosts of D. reticulatus.

Skeletal trauma reflects hunting behaviour in extinct sabre-tooth cats and dire wolves

Skeletal-injury frequency and distribution are likely to reflect hunting behaviour in predatory vertebrates and might therefore differ between species with distinct hunting modes. Two Pleistocene predators from the Rancho La Brea asphalt seeps, the sabre-tooth cat, Smilodon fatalis, and dire wolf, Canis dirus, represent ambush and pursuit predators, respectively. On the basis of a collection of over 1,900 pathological elements, the frequency of traumatic injury across skeletal elements in these two species was calculated. Here we show that the frequency of trauma in the sabre-tooth cat exceeds that of the dire wolf (4.3% compared to 2.8%), implying that the killing behaviour of S. fatalis entailed greater risk of injury. The distribution of traumatic injuries also differed between the two species. S. fatalis, an ambush predator, was injured more often than expected across the lumbar vertebrae and shoulders whereas C. dirus, a pursuit predator, had higher than expected levels of injury in the limbs and cervical vertebrae. Spatial analysis was used to quantify differences in the distribution of putative hunting injuries. Analysis of injury locations discriminated true hotspots from injury-dense areas and facilitated interpretation of predatory behaviour, demonstrating the use of spatial analyses in the study of vertebrate behaviour and evolution. These results suggest that differences in trauma distribution reflect distinct hazards of each species' hunting mode.

Mesocarnivores and macroparasites: altitude and land use predict the ticks occurring on red foxes (Vulpes vulpes)

Background

The red fox Vulpes vulpes is the most common mesocarnivore in Europe and with a wide geographical distribution and a high density in most terrestrial habitats of the continent. It is fast urbanising species, which can harbor high numbers of different tick species, depending on the region. Here we present the results of a large-scale study, trying to disentangle the intricate relationship between environmental factors and the species composition of ectoparasites in red foxes. The samples were collected in Transylvania (Romania), a region with a diverse geography and high biodiversity. The dead foxes (collected primarily through the National Surveillance Rabies Program) were examined carefully for the presence of ticks.

Results

Ticks (n = 4578) were found on 158 foxes (out of 293 examined; 53.9%). Four species were identified: Dermacentor marginatus, Ixodes canisuga, I. hexagonus and I. ricinus. The most common tick species was I. hexagonus (mean prevalence 37.5%, mean intensity 32.2), followed by I. ricinus (15.0%; 4.86), I. canisuga (4.8%; 7.71) and D. marginatus (3.7%; 3.45). Co-occurrence of two or more tick species on the same host was relatively common (12.6%), the most common co-occurrence being I. hexagonus - I. ricinus. For D. marginatus and I. canisuga the highest prevalence was recorded in lowlands, for I. hexagonus in hilly areas, while for I. ricinus in mountains.

Conclusions

Altitude influenced the intensity of parasitism, with highest intensity observed for all Ixodes species in hilly areas. Dermacentor marginatus occurred only in lowlands, I. canisuga in lowlands and hilly areas while the other two species occurred in all of the regions studied. Foxes from lower altitudes had the most tick species associated, with most incidences of co-parasitism also recorded here. Land use affected tick-species composition, with the presence of D. marginatus strongly associated with the extension of arable areas and lack of forests. The presence of I. hexagonus was determined only by the extent of arable lands. As foxes are frontrunners of wildlife urbanization process, with a continuous increase of their numbers in urban areas, the knowledge of their ticks’ ecology (and the pathogens vectored by these) is of utmost importance.

A review of canine babesiosis: the European perspective

Canine babesiosis is a significant tick-borne disease caused by various species of the protozoan genus Babesia. Although it occurs worldwide, data relating to European infections have now been collected for many years. These data have boosted the publication record and increased our working knowledge of these protozoan parasites. Both the large and small forms of Babesia species (B. canis, B. vogeli, B. gibsoni, and B. microti-like isolates also referred to as "B. vulpes" and "Theileria annae") infect dogs in Europe, and their geographical distribution, transmission, clinical signs, treatment, and prognosis vary widely for each species. The goal of this review is to provide veterinary practitioners with practical guidelines for the diagnosis, treatment and prevention of babesiosis in European dogs. Our hope is that these guidelines will answer the most frequently asked questions posed by veterinary practitioners.

Dynamics of tick infestations in foxes in Thuringia, Germany

This study aimed to provide up-to-date information on the dynamics of tick infestations on foxes in Thuringia, as the most recent information available was published in 1997. Fox carcasses that had been sent to the Thuringian State Authority for Food Safety and Consumer Protection (Thüringer Landesamt für Lebensmittelsicherheit und Verbraucherschutz - TLLV), between January 1st and December 31st, 2009, were examined for the presence of ticks. All ticks collected were stored at -20 °C before being identified and classified according to their developmental stage and sex. Out of a total of 1286 foxes examined, 989 (76.9%) were infested with ticks. A total of 13,227 ticks were collected from the foxes. The stage most frequently found was the larva (48.1%), followed by the adult (34.1%), and the nymphal stage (17.8%). Regarding the adult stage, Ixodes ricinus was the most frequent tick species detected (82.2%), followed by I. canisuga (10.8%) and I. hexagonus (6.7%). Dermacentor reticulatus ticks were very rare (0.3%). With regard to nymphs, I. canisuga and I. hexagonus were the most frequent tick species found, and this was also assumed for the larval stage. The results indicate the occurrence of tick infestations in foxes throughout the year, mainly by I. ricinus, I. canisuga, and I. hexagonus, with seasonal variations. Foxes were infested by I. ricinus ticks significantly more frequently from April to September. This applied to all tick developmental stages, but especially to adults. In contrast to I. ricinus, the infestation of foxes with I. canisuga and I. hexagonus was significantly higher from January to March and from October to December, especially with the immature developmental stages.

The occurrence of ixodid ticks on wild mink Mustela vision in England and Wales

Four species of ticks found to infest 1391 American mink (Mustela vison) in Britain in five years were, in declining order of frequency, Ixodes hexagonus, Ixodes canisuga, Ixodes ricinus and Ixodes acuminatus. Ixodes hexagonus and I. canisuga occurred on 40% and 2.5% of mink respectively. Infestation rates (the proportion of infested mink) of adult females, nymphs and larvae were similar and tended to be lower in summer. The distribution of infestation size (the number of ticks per host) for adult females describes a negative binomial. The mean infestation size of nymphs varied with the sex of the host was 5.2 for males and 4.2 for females. Mink are competent hosts for I.hexagonus.

Biology of Ixodes (Pholeoixodes) hexagonus under laboratory conditions. Part II. Effect of mating on feeding and fecundity of females

The effect of mating on the feeding and fecundity of Ixodes (Pholeoixodes) hexagonus females was studied under controlled laboratory conditions of 22-23 degrees C and 98% relative humidity. The feeding period of mated females was 6-15 days and 11-13 days for unmated females. The mean weight of the engorged mated females was 114.84 +/- 45.89 mg, whereas, that of the engorged unmated females was significantly lower (80.61 +/- 28.84 mg). During the initial slow feeding period, the weight of mated females increased 6.6 times. At the end of the blood feeding, they had increased their initial weight 35.5 times. Unmated females never entered the rapid engorgement phase and up to 12 days of feeding period their mean weight did not increase more than 9.2 times. The pre-oviposition periods of mated and unmated females were 6-15 days and 4-12 days, respectively. The mean of the egg production efficiency was 40.26 +/- 12.47% for mated females and 35.68 +/- 12.2% for unmated females. The mean of the mass conversion efficiency was 73.6 +/- 13.7% for mated females and 66.48 +/- 16.55% for unmated females. Sixty per cent of the eggs deposited by mated females hatched whereas only 1% of the eggs deposited by unmated females hatched. These results indicate that I. hexagonus females possess some predisposition for parthenogenesis and only fertility and not fecundity depends on mating.

The dispersion of the Karoo paralysis tick, Ixodes rubicundus, within a naturally infested population of sheep in South Africa

The ratio of variance to mean (s2/means) of numbers of Ixodes rubicundus (males and females) per sheep was used as a measure of the dispersion pattern of this tick within a naturally infested population of sheep. Sheep were divided into two groups, one with previous contact with I. rubicundus and the other with no previous contact. Samples of 10 sheep from each group were searched for ticks on a weekly basis for 19 weeks during the winter of 1986. In each group, both male and female ticks had an s2/means ratio greater than 1 for the majority of observation periods indicating an aggregated dispersion pattern. The degree of aggregation was greater with increasing density of the ticks. The implications of these results are discussed both in relation to sampling procedures and potential control strategies.