Helminths of red foxes (Vulpes vulpes) in Denmark

An epidemiological study of helminths in 1040 red foxes collected from various localities in Denmark during 1997-2002, revealed 21 helminth species at autopsy, including nine nematode species: Capillaria plica (prevalence 80.5%), Capillaria aerophila (74.1%), Crenosoma vulpis (17.4%), Angiostrongylus vasorum (48.6% from Northern Zealand (endemic area)), Toxocara canis (59.4%), Toxascaris leonina (0.6%), Uncinaria stenocephala (68.6%), Ancylostoma caninum (0.6%), and Trichuris vulpis (0.5%); seven cestodes: Mesocestoides sp. (35.6%), a number of Taeniid species (Taenia pisiformis, T. hydatigena, T. taeniaeformis, T. crassiceps, and unidentified Taenia spp.) (22.8%), and Echinococcus multilocularis (0.3%); four trematodes: Alaria alata (15.4%), Cryptocotyle lingua (23.8%), Pseudamphystomum truncatum (3.6% from Northern Zealand), and Echinochasmus perfoliatus (2.4% from Northern Zealand); one acanthocephalan: Polymorphus sp. (1.2%). Significant difference in prevalence was found for T. canis and A. vasorum according to host sex, and for T. canis, U. stenocephala, Mesocestoides sp., Taenia spp., A. alata, A. vasorum, and Capillaria spp. according to age groups (adult, young or cub). Prevalence and average worm intensity for each helminth species varied considerably according to geographical locality, season, and year. Aggregated distribution was found for several helminth species. The two species E. multilocularis and E. perfoliatus are first records for Denmark.     

Echinococcus multilocularis and Toxocara canis in urban red foxes (Vulpes vulpes) in Brussels, Belgium

During the last decades, European red foxes (Vulpes vulpes) have been implicated in the transmission of several viral or parasitic pathogenic agents to domestic animals and humans. In urban areas, risks of zoonoses transmission are likely to increase as a result of a higher rate of intra- and inter-species contacts. Foxes occur on 35% of the Brussels-Capital Region area and local densities reach up to 4 family groups per square kilometre. According to the directive 2003/99/ECC, a first survey for the presence in foxes of Echinococcus multilocularis and Toxocara canis was conducted in Brussels from 2001 to 2004. None of 160 foxes were found to be infected with E. multilocularis and 24 of 134 foxes were found to be infected with T. canis. Considering numbers of examined foxes, the sensitivity and the specificity of tests used for diagnosis, the 95% credibility intervals for the true prevalence of E. multilocularis and T. canis were estimated in a Bayesian framework to be 0 to 1.87% (median value of 0%) and 12.7 to 26% (median value of 18.7%), respectively. For T. canis, a significantly higher risk to be a carrier occurs in cubs and a significantly lower risk in adults.     

A parasitological survey of wild red foxes (Vulpes vulpes) from the province of Guadalajara, Spain

An epizootiological survey of leishmaniosis, coccidiosis and parasitic helminths in 67 foxes (Vulpes vulpes) was conducted in Guadalajara (central Spain). Examination for parasitic protozoa revealed prevalences of 74% Leishmania (determined by molecular methods) and 2.9% coccidia oocysts (fecal flotation). Survey of parasitic helminths (fecal flotation/necropsy) demonstrated the presence of nine species, including six nematodes, two cestodes and one trematode. Nematodes were the most common parasites of foxes, followed by cestodes and trematodes. Greater levels of nematodes like Uncinaria, with a free-living stage in its life-cycle, were found in foxes in areas where moist soils were likely to exist, in contrast to areas of semiarid characteristics, where Toxascaris leonina or Trichuris vulpis were predominant. With regard to helminths of importance as human pathogens, trichinoscopy revealed the presence of a relatively high number of foxes (8.9%) infected with Trichinella spiralis. Finally, Toxocara canis infection was less frequent (4.4%) than trichinellosis.     

Ectoparasite infestations of red foxes (Vulpes vulpes) in Hungary

A survey was carried out to investigate the ectoparasite infestations of 100 red foxes (Vulpes vulpes) in Hungary. The overall prevalence of flea and tick infestation was high (62 and 86% with the dominance of the anthropophil Pulex irritans and Ixodes ricinus), but the number of parasites was low to moderate. Felicola vulpis was not found in the present study, and the prevalence of Otodectes cynotis was only 2%. Based on prevalence (21%), mange lesion scores, and the negative correlation between lesion scores and condition of foxes, Sarcoptes infestation should be considered as the most important parasitosis of foxes in Hungary. Besides the ecological significance of these parasites, the high overall prevalence of mange and anthropophil flea and tick infestations of foxes and the appearance of these animals in the synanthropic environment as a result of the increasing population size, may result in the increasing incidence of flea, tick and accidental mite infestation of man and domestic animals, and may enhance the transmission rate of some vector-borne diseases.     

Rickettsiae in arthropods collected from red foxes (Vulpes vulpes) in France

The aim of our study was to detect the presence of Rickettsia spp. and Bartonella spp. in ticks and fleas collected from red foxes (Vulpes vulpes) in southeastern France during 2008. Using a genus-specific quantitative PCR (qPCR) assay, which was followed by a species-specific qPCR assay for the positive samples, 45.2% (33/73) of ticks (Rhipicephalus turanicus) were found to be infected with Rickettsia massiliae. 10.5% (2/19) of the fleas (Archaeopsylla erinacei) collected in the study tested positive for Rickettsia felis. A genus-specific qPCR assay did not reveal any Bartonella species in any of the ticks or fleas collected. The role of red foxes in the epidemiology of spotted fever caused by Rickettsiae species requires further investigation.     

Extraintestinal nematode infections of red foxes (Vulpes vulpes) in Hungary

A survey was carried out to investigate the prevalence and worm burden of extraintestinal nematodes in 100 red foxes (Vulpes vulpes) of Hungary. The overall prevalence of nematode infections of the respiratory tract was 76%. Eucoleus aerophilus (Capillaria aerophila) was the predominant species (66%), followed by Crenosoma vulpis (24%), Eucoleus (Capillaria) b?hmi (8%) and Angiostrongylus vasorum (5%). Pearsonema (Capillaria) plica was found in 52% of the urinary bladders. In 3% of the foxes, Trichinella britovi was present in muscle samples. The high prevalence of lungworms and P. plica and the fox colonisation in urban areas may enhance the prevalence of these nematode infections in domestic dogs and cats, and the flow of T. britovi from the sylvatic cycle to the domestic cycle, enhancing the risk of infections in humans.     

Prevalence of antibodies against Toxoplasma gondii and Neospora caninum in Hungarian red foxes (Vulpes vulpes)

In the present study we have investigated the seroprevalence to the protozoan parasites Toxoplasma gondii and Neospora caninum in 337 red foxes (Vulpes vulpes) from 16 out of 19 counties in Hungary. The foxes were originally collected within a National vaccination program against rabies. Antibodies to T. gondii were detected in as many as 228 (68%) of the foxes using a commercial direct agglutination test (DAT). In an indirect iscom ELISA, five foxes (1.5%) were positive for antibodies against N. caninum. The high prevalence of foxes positive for T. gondii might be explained by the widespread occurrence of the parasite in the diet of foxes. As a contrast, latent infections of N. caninum among red foxes in Hungary are much less common.     

Occurrence of Giardia and Cryptosporidium in Norwegian red foxes (Vulpes vulpes)

Faecal samples from 269 Norwegian wild red foxes (Vulpes vulpes) shot during the hunting season (October-April) in 2002-2004 were examined for the presence of Giardia and Cryptosporidium. Cryptosporidium oocysts were detected in samples from 6 (2.2%) of the foxes, and Giardia cysts in 13 (4.8%) of the foxes. The prevalence of Giardia infection was significantly higher in juvenile male foxes than in adult male foxes, but no other significant differences between age and sex were found. No significant differences in prevalence related to geographical origin of animals were found. Insufficient nucleated Cryptosporidium oocysts were isolated for successful PCR, but genotyping of Giardia duodenalis isolates from seven foxes demonstrated a high degree of heterogeneity amongst them, with all isolates belonging to the zoonotic Assemblages A and B.     

Experimental infection of red foxes (Vulpes vulpes) with Sarcoptes scabiei var. vulpes

Two of 3 red foxes became experimentally infected with Sarcoptes scabiei v. vulpes isolated from a naturally infected wild fox. The first clinical sign was seen after 10 days. After 30 days hairless patches were observed on the back of one of the foxes while general hair loss continued slowly. On the other fox the only macroscopical changes was tangling of the hair. The foxes died after 67 and 94 days, respectively. Both foxes were anaemic and in very poor condition. Scratching was seen in only 1 of the foxes.     

Origin of maternally transferred antibodies against rabies in foxes (Vulpes vulpes)

During previous experiments, maternal antibodies against rabies were detected in the sera of fox cubs whelped by orally immunised vixens. These antibodies appear to be transferred exclusively via the colostrum. No evidence of maternally transferred immunity in the form of immunoglobulin G was found in 80 fox embryos collected from 19 rabies-immune vixens originating from areas where oral rabies vaccine baits had been distributed.     

Infectivity of Trichinella papuae for experimentally infected red foxes (Vulpes vulpes)

To evaluate infectivity for carnivores as well as other biological characteristics of the newly described Trichinella papuae, eight red foxes were experimentally infected with the parasite. Five weeks after inoculation, T. papuae larvae were recovered from nine different muscle types. The larvae recovered from muscle tissue were shown to be infective to mice, to have a very low tolerance to freezing, and to survive longer than the other Trichinella genotypes in decaying tissue up to 5 weeks after infection.     

Experimental infection of European red foxes (Vulpes vulpes) with canine herpesvirus

We report on the pathogenicity of canine herpesvirus (CHV) for European red foxes. In the first experiment, we inoculated 10 adult foxes intravenously with a canine isolate of CHV. All foxes became infected and shed CHV in saliva and genital secretions for up to 14 days post-inoculation (p.i.) as evaluated by PCR and/or by virus isolation. All foxes developed clinical signs such as fever, lethargy and evidence of respiratory tract disease. Two foxes died on day 6 p.i., one on day 7 p.i., and one fox was euthanased on day 6 p.i. Tissues taken from the four dead foxes were positive for CHV by PCR. The remaining six foxes recovered after approximately 14 days p.i. Virus particles with morphology typical of herpesviruses were found by electron microscopy in the liver of an infected animal. All surviving foxes developed serum anti-CHV antibodies. In a second experiment, six foxes were dosed perorally with CHV and paired with six untreated controls. Neither the perorally dosed nor the in-contact control foxes developed clinical signs of disease. Infectious CHV was not isolated from any of the dosed or the in-contact foxes but all perorally-infected foxes and one of the in-contact foxes tested PCR-positive for CHV on several occasions p.i. All perorally-infected foxes, but none of the in-contact foxes, seroconverted. In summary, intravenous CHV inoculation caused a clinical disease in adult foxes much more severe than observed in experimentally-infected adult dogs. No clinical disease or virus spread was observed after peroral dosing although viral infection occurred as evidenced by seroconversion.     

Prevalence of Trichinella larvae and extra-intestinal nematodes in Norwegian red foxes (Vulpes vulpes)

A survey of the parasitic fauna of the Norwegian red fox (Vulpes vulpes) population was carried out in 1994/1995 and 2002-2005. All foxes were killed during the licensed hunting season from October to April and, in total, 393 animals from all regions of the country were examined. The present study details the results of extra-intestinal nematode and Trichinella larvae examinations. All individuals were examined for Trichinella, using routine digestion methods. Parasitological examination of the internal organs of some of the foxes also identified a number of different extra-intestinal nematodes. The following prevalences were identified (number positive/number foxes examined): Trichinella larvae 19/393 (4.8%); Capillaria b?hmi (C. b?hmi) 88/174 (51%); Capillaria aerophila (C. aerophila) 160/181 (88%); Crenosoma vulpis (Cr. vulpis) 105/181 (58%) and Capillaria plica (C. plica) 81/154 (53%). No evidence of Angiostrongylus vasorum infection was found. The 19 different Trichinella isolates were species typed by PCR and sequence analysis; 18 isolates were identified as Trichinella nativa and one as Trichinella britovi. A wide geographical distribution of the parasites was seen. The following exceptions were recorded: C. b?hmi, the prevalence of which was significantly lower in northern Norway (6%) compared to other regions (central Norway, eastern Norway and southern and western Norway; 52-57%). There was a significantly higher prevalence of Trichinella infection in eastern Norway (8.1%), when compared with the rest of the country (0.6%). Cr. vulpis prevalence was significantly higher in central Norway (83%) than in other regions (41-56%). There were no significant differences in age and sex distribution of the parasites with the exception of Cr. vulpis where juvenile foxes had a greater likelihood of infection. The data also indicated that adult foxes were more commonly infected with Trichinella larvae (5.8%) than juveniles (3.3%) (no statistical significance).     

Distribution of opisthorchiid liver flukes in red foxes (Vulpes vulpes) in western Brandenburg

226 (= 43.9%) out of 515 red foxes originating from the western districts of the Federal State Brandenburg were positive for opisthorchiid flukes. Metorchis bilis, Opisthorchis felineus and Pseudamphistomum truncatum occurred in prevalences of 36.9, 8.9 and 0.2% respectively. Although low fluke burden were predominant the maximum number of each fluke species isolated was 419, 46, and 78 respectively. No clear relations were found between the liver fluke prevalence and the proportion of surface waters of the different administrative districts. However, most positive foxes originated from municipalities closely situated to rivers, canals, and lakes.     

Survey for Trichinella spp. in red foxes (Vulpes vulpes) in Belgium.

Concurrently with a survey for Echinococcus multilocularis in the red fox (Vulpes vulpes) in Flanders, northern Belgium, serological and parasitological analyses for Trichinella spp. were carried out from 1996 to 1999. Muscle samples from foxes in Wallonia, southern Belgium, were obtained during a survey for rabies and alveolar echinococcosis from 1998 to 2000.In muscle samples from tongue, diaphragm, hindlegs and tail of 179 Flemish foxes no larvae were found by trichinoscopy. Serum and muscle juice of, respectively 176 and 26 animals were examined using an ELISA for the detection of antibodies against excretory-secretory (ES) antigen. There were eight (4.5%) positive sera, but no positive muscle juice samples.All muscle samples from 639 foxes in Wallonia proved to be negative for larvae in artificial digestion. Serum and muscle juice of 130 and 478 foxes, respectively were examined in ES-ELISA. There were 61 (46.9%) positive sera and 90 (18.8%) positive muscle juice samples. A comparison between 88 serum and muscle juice samples of the same foxes showed that only half of the serum-positive animals were detected using muscle juice. However, for establishing the true meaning of these results, a more profound epidemiological study on the vulpine population in Belgium is necessary.