Under the skin: Ixodes ticks in the subcutaneous tissue of red foxes (Vulpes vulpes) from Germany

Abstract

Background: Ixodes spp. are vectors of zoonotic pathogens. All three active life stages (larvae, nymphs, adults) need to feed on a host in order to develop. Usually ticks parasitize attached to the external surface of their hosts' skin. Interestingly, in some cases ticks can also be found in the subcutaneous tissue in a variety of hosts, such as red foxes (Vulpes vulpes), raccoon dogs (Nyctereutes procyonoides) and dogs. Methods:The visceral side of 126 red fox-furs from Germany was examined visually searching for ticks. The localization of ticks was recorded and assigned to ten specific body parts. Morphological identification of ticks was performed according to standardized taxonomic protocols. Ticks which could not be further identified were examined genetically via conventional PCR targeting the 16S rRNA and cox1 gene. Hematoxylin and eosin (H&E) staining was used for histopathological examination.Results: In 111 out of 126 (88.1%) examined coats, at least one tick was found in the subcutaneous tissue. A total of 1203 ticks were removed from the subcutaneous tissue. Well-preserved ticks could be identified based on morphological criteria, but most ticks were in a progressed state of decomposition. Here, morphological species identification was not successful. Also, PCR methods did not lead to a successful species identification. The following species and development stages were found by morphological identification: Ixodes ricinus (female, n = 289; male, n = 8; nymph, n = 1), I. hexagonus (female, n = 2), I. canisuga (female, n = 1). Male I. ricinus were found individually or copulating in pairs with females. Subcutaneous ticks were localized at three predominant affected body parts: ears, axillar and inguinal region. Histological examination of subcutaneous ticks revealed a granulomatous panniculitis. Conclusions:To the authors' knowledge, this is the first finding of highly prevalent subcutaneous ticks in red foxes from Germany. Subcutaneous location of ticks seems to be very common in red foxes and the rule rather than the exception. Deep embedment of longirostra and long feeding times of females seem to put the subcutaneous location in favor. Most foxes were infested in the inguinal area, where the skin is thin and less hairy.

Subcutaneous ticks: a first report in a golden jackal, and their absence in non-canid carnivores

“…Ixodes spp.) or that feed for longer periods (adults in general and females in particular), which seem to be predisposing factors [ 7 , 8 ]. Although the vast majority of reports of subcutaneous ticks concern red foxes (Table 1 ), it is not clear if host-related factors are involved.…”

Subcutaneous ticks: first report in a golden jackal and further proof for the negativity of non-canid carnivores

“…What is clear at the moment is that so far, with the exception of one human case, all other reports originate from canids, with high local prevalence in red foxes [7,8]. The vast majority of these reports refer to ticks of genus Ixodes (Table 1) but this may also be related to the more common occurrence of these ticks in red foxes [10,11].…”

“…Ixodes spp.) or ticks feeding for longer periods (adults in general and females in particular), which seem to be predisposing factors [7,8]. Although it is evident that the vast majority of reports of subcutaneous ticks are from red foxes (Table 1), it is not clear if also host-related factors are involved.…”

Subcutaneous ticks: first report in a golden jackal and their absence in non-canid carnivores

“…Ixodes spp.) or ticks feeding for longer periods (adults in general and females in particular), which seem to be predisposing factors [7,8]. Although it is evident that the vast majority of reports of subcutaneous ticks are from red foxes (Table 1), it is not clear if host-related factors are involved.…”

“…So far, with the exception of one human case, all other reports originate from canids, with high local prevalence in red foxes [7,8]. The vast majority of these reports refer to ticks of the genus Ixodes (Table 1) but this may also be related to the more common occurrence of these ticks in red foxes [10,11].…”