Behavioural Changes in Free-ranging Red Foxes (Vulpes vulpes) due to Sarcoptic Mange

Sarcoptic mange (Sarcoptes scabiei var. vulpes) reached Scandinavia in the mid-1970’s and is mainly prevalent among red foxes (Vulpes vulpes) (Borg 1987). In the laboratory, foxes succumb 2–4 months after being infested, and it is commonly thought that carriers in the wild exhibit an abnormal behaviour and quickly die (Mörner & Christensson 1984, Holt & Berg 1990). However, there is a lack of comparative data from free-ranging animals to contribute to the ecology of the species in general and ta supplement the content of the above selected references in particular (e.g. Plowright 1988). Using telemetry studies, I have compared the behaviour in winter of 2 mange infested and 2 healthy red foxes. The work took place in 1987 and 1990 in a boreal area adjacent to farmland in central Norway (63° 20′N 10° 45′E).     

Notoedric and sarcoptic mange in free-ranging lynx from Switzerland

Between March and December 1999, five free-ranging lynx (Lynx lynx) affected by mange were found dead or shot by game wardens in the Swiss Alps. In the first two cases, Notoedres cati was isolated from the skin; in the third and fourth case, Sarcoptes scabiei was the cause of the infection; and in the fifth case, a mixed infection was diagnosed. Red foxes (Vulpes vulpes) affected with sarcoptic mange and domestic cats infested with N. cati are likely to be the sources of infection. It seems improbable that mange will occur as an epidemic in lynx in Switzerland, but losses due to infections with N. cati and/or S. scabiei may have an impact on this small, geographically limited lynx population. This is the first report of notoedric mange in a free-ranging lynx and the first report of mange in lynx from Switzerland.     

Morbidity and mortality of red foxes (Vulpes vulpes) and gray foxes (Urocyon cinereoargenteus) admitted to the Wildlife Center of Virginia, 1993-2001

The medical records of 48 red foxes (Vulpes vulpes) and 35 gray foxes (Urocyon cinereoargenteus) examined at the Wildlife Center of Virginia (Waynesboro, Virginia, USA) from 1993 to 2001 were reviewed. The most common diagnosis in red foxes was orphaned (33%), followed by trauma (27%), undetermined diagnosis (23%), and sarcoptic mange (17%). Trauma (46%) was the most frequent cause of morbidity and mortality in gray foxes followed by orphaned (23%), undetermined (20%), toxoplasmosis (6%), presumptive canine distemper (3%), and rabies (3%). One gray fox had concurrent toxoplasmosis and presumptive canine distemper (3%). Similar diseases were detected in previous studies at a diagnostic laboratory; however in this study, trauma and orphaned animals were more common than infectious diseases. The lack of diagnostic information on some cases limited the usefulness of this study, and more emphasis should be placed on performing postmortem examinations of wildlife presented to wildlife rehabilitation centers.     

Studies of disease in the Red fox (Vulpes vulpes) in Northern Ireland

Some 720 foxes were examined for signs of disease and parasites, incidental to an intensive ecological study. The epifauna, skin infections, intestinal helminths and lesions of internal organs are described and rates of infection given. Important diseases included sarcoptic mange, which is a major debilitating factor and probably a fatal infection. Leptospirosis was common, antibodies were recorded in the blood, and chronic interstitial nephritis was a frequent condition of the kidneys. The nematodes Uncinaria stenocephala and Toxocara spp. were often present as parasites of the alimentary canal and may be a mortality factor in cubs. The cestodes and ectoparasites alone would appear to be of little importance and largely reflect the diet of the fox.     

Sarcoptic mange in raccoons in Michigan

Sarcoptic mange is a cause of pruritic skin disease in domestic dogs and a wide range of wildlife species. We describe sarcoptic mange in free-ranging raccoons (Procyon lotor). Three adult raccoons from upper Wayne County, Michigan (USA), were captured, killed, and submitted for diagnostic evaluation. The animals were intensely pruritic, and two had advanced alopecic and crusting lesions over their dorsum and hind limbs. Skin scrapings and skin biopsies revealed crusting and hyperkeratotic dermatitis with high numbers of Sarcoptes scabiei adults, larvae, nymphs, and eggs. These raccoons were not otherwise debilitated, with minimal internal parasites, good body condition, and no evidence of infectious bacterial or viral diseases. Because sarcoptic mange is highly contagious and affects many species, including humans, transiently, it is important that wildlife biologists and rehabilitators include sarcoptic mange in their differential list for raccoons exhibiting pruritus and alopecia.     

Seasonal and age changes in the thymus gland of the Red fox, Vulpes vulpes,

Seasonal and age changes in thymus weight and histological structure were examined in the Red fox ( Vulpes vulpes ). Growth in the fox thymus slowed down after birth compared with the last third of foetal existence, but the gland still grew rapidly to reach a peak first year weight when the cubs were 20 weeks of age. From this point the thymus in both sexes decreased markedly in weight to reach a low point by the beginning of the first breeding season. During this involution lobule structure broke down and adipose tissue and connective tissue was laid down in the gland. Recovery of the thymus towards the second year weight maximum was accompanied by the regaining of lobule structure and the gland resembled that of the juvenile again. The male thymus increased in weight from the middle of the mating season, but recovery in the female thymus was delayed until the end of lactation. Involution occurred prior to the second breeding season. Thereafter, the gland never attained the high weights seen in the first two years of life, but histological changes still occurred even in old animals. The thymus gland of animals infected with sarcoptic mange is described.     

Invading parasites cause a structural shift in red fox dynamics

The influence of parasites on host life histories and populations is pronounced. Among several diseases affecting animal populations throughout the world, sarcoptic mange has influenced many carnivore populations dramatically and during the latest epizootic in Fennoscandia reduced the abundance of red fox by over 70%. While the numerical responses of red fox populations, their prey and their competitors as well as clinical implications are well known, knowledge of how sarcoptic mange affects the structure of the dynamics of red fox populations is lacking. Integrating ecological theory and statistical modelling, we analysed the long-term dynamics (1955-1996) of 14 Danish red fox populations. As suggested by the model, invading sarcoptic mange significantly affected direct and delayed density dependence in red fox dynamics and concomitant shifts in fluctuation patterns were observed. Our statistical analyses also revealed that the spatial progressive spread of mange mites was mirrored in the autocovariate structures of red fox populations progressively exposed to sarcoptic mange.     

Fecundity and egg output by Toxocara canis in the red fox, Vulpes vulpes

The role of the red fox Vulpes vulpes in the dissemination of eggs of Toxocara canis into the environment is considered with reference to female worm fecundity and egg output in the faeces of infected foxes collected from four localities in southern England. A significant positive correlation was found between female worm size and the number of eggs in the uterus but there was no significant relationship between T. canis worm numbers and egg output in fox faeces. Reliable estimates of worm burdens in foxes could not, therefore, be determined from faecal egg counts alone. The highest mean egg output of 2145.0 epg recorded from adult foxes indicated that fox cubs are not necessarily the main sources of environmental contamination with T. canis eggs. Saturated magnesium sulphate was found to be a more effective flotation solution than zinc sulphate and sodium chloride for recovering eggs from fox faecal samples.     

Susceptibility of red and gray foxes to infection by Ehrlichia chaffeensis

Red foxes (Vulpes vulpes) and gray foxes (Urocyon cinereoargenteus) were evaluated for their susceptibility to experimental infection with Ehrlichia chaffeensis, the causative agent of human monocytotropic ehrlichiosis. Two red foxes and three gray foxes were inoculated intravenously with E. chaffeensis (15B-WTD-GA strain) and were monitored at 7, 14, 21, and 28 days post inoculation (DPI) for evidence of infection using an indirect fluorescent antibody (IFA) assay, light microscopy, polymerase chain reaction (PCR), and cell culture methods. One red fox and one gray fox served as negative controls. Red foxes were susceptible to infection based on reisolation of E. chaffeensis from blood at 7 and 14 DPI, seroconversion by 7 DPI, and positive PCR assays on spleen and lymph nodes at 28 DPI. Morulae were not found in circulating leukocytes and clinical signs or lesions of ehrlichiosis were not observed. In contrast, gray foxes were refractory to infection based on negative results on all culture, PCR, serologic, and microscopic examinations. These findings imply that red foxes, but not gray foxes, are potential vertebrate reservoirs for E. chaffeensis. These findings also illustrate the need to verify serologic evidence of E. chaffeensis infection among wild animals.     

Eradication of Porcine Sarcoptic Mange within a Health Declared Production Model

The success of a large-scale eradication programme against sarcoptic mange was evaluated in piglet producing herds belonging to the health class LSO 2000. These farms are monitored to be free from sarcoptic mange, swine enzootic pneumoniae, swine dysentery and progressive atrophic rhinitis. The local veterinarians were instructed to eradicate sarcoptic mange from the herds by 2 ivermectin injections 14 days apart or 3 treatments with phoxim pour-on 6 days apart before the farms were able to join the health class. The study consisted of a questionnaire administered to the farmers, farm visits and follow-ups associated with the regular control of the health class. A questionnaire was sent to all of the 379 accepted farrowing farms. Altogether 323 farmers had initiated an eradication programme at least 7 months before the questionnaire was distributed and 96% of them believed that the mange eradication programme had been successful. In most of the successful herds (90%), the local veterinarian had treated the animals by the recommended methods, and the majority of the farmers (88%) had cleaned and sprayed the pens with insecticides on the days of treatment. Three out of the 7 unsuccessful farms had employed methods other than those recommended. Twenty-five herds were randomly selected for an intensified control. The rubbing index was ≤0.1 in all herds visited, indicating freedom from mange. Sows or gilts, 15–20 animals per farm, were skin scraped and no Sarcoptes scabiei was found. The same animals were blood sampled and serum antibodies to S. scabiei were measured by an indirect ELISA. All except 1 farm had low optical density (OD) values in most of the samples. The owner of that farm had become uncertain about the mange status of the herd and had recently retreated all animals with acaricides. The number of complaints about mange in the finishing units buying health class feeder pigs was low. The study demonstrates that it is possible to run an eradication programme against sarcoptic mange, in which a large number of farmers together with their veterinarians participate. It is possible to eradicate mange not only at the herd but also at the population level. The ELISA test employed proved to be a possible tool to monitor the efficacy of mange-eradication programmes.     

Flexible spatial organization of urban foxes, Vulpes vulpes, before and during an outbreak of sarcoptic mange

The social and spatial organization of urban fox groups prior to and during an outbreak of sarcoptic mange was compared with predictions derived from the resource dispersion hypothesis (RDH). We investigated the availability of three key resources. Neither daytime rest sites nor breeding sites appeared to be limited in availability. The availability of food deliberately supplied by local householders was examined by questionnaire surveys. The daily and weekly amount of food supplied was greatly in excess of the minimum requirements of a pair of foxes, but was consistent between territories. The availability of this food source increased markedly as a result of more people feeding the foxes. In agreement with the RDH, group size prior to the outbreak of mange increased from 2.25 animals (N=4) to 6.57 animals (N=7). Before the outbreak of mange, two territories were divided. Increased scavenge availability on smaller territories may have promoted these changes. Excluding these spatial changes, territories were very stable between years. After the outbreak of mange, group size declined as a direct result of mange-induced mortality. Surviving animals increased their ranges only after neighbouring groups had died out. Ranges did not increase in size in response to a decline in food availability. Nor were the increases in range size associated with the relinquishment of parts of the existing territory. These postmange changes are contrary to the RDH. Three factors may have promoted these changes: the elimination of interstitial space, the forced dispersal of young or future division of the territory. Copyright 2000 The Association for the Study of Animal Behaviour.     

Sarcoptic mange in free-ranging pampas foxes in the Gran Chaco,Bolivia

Sarcoptes scabiei infestation was diagnosed in two freshly dead free-ranging pampas foxes (Pseudalopex gymnocercus) in the Gran Chaco, Bolivia. Diagnosis was made based on histologic evaluation of skin biopsies and identification of the parasite from skin scrapings. Characteristic gross lesions consistent with mange were noted in 19 of 94 observations of free-ranging pampas foxes in the region from December 1998 to January 2000. None of 16 crab-eating foxes (Cerdocyon thous) observed during the same time period had visible lesions consistent with scabies. These are the first case reports of S. scabiei in pampas foxes.     

Reproductive management of silver foxes (Vulpes vulpes) in captivity

Specific protocols need to be developed that take into consideration the requirements of silver foxes. This study was designed to investigate the reproduction of 26 pairs of silver foxes (Vulpes vulpes). Reproduction parameters (breeding season, age at puberty, fecundity and fertility) of the foxes were examined under experimental conditions, and new techniques to optimize fox breeding were assessed. Staining of the vaginal smears with the double Harris-Schorr stain allowed for the precise detection of estrus and proved to be more reliable than simply measuring vaginal resistance. Ultrasonography was demonstrated to be useful for pregnancy diagnosis and prediction of parturition. Results demonstrate that the methods reported in this paper are easily applicable to similar studies carried out on small groups of animals within the framework of fox animal experimentation.     

Sarcoptic mange vulnerability in carnivores of the Białowieża Primeval Forest,Poland: underlying determinant factors

Sarcoptic mange caused by Sarcoptes scabiei, is a highly contagious worldwide mite infection responsible for epizootic skin disease in populations of wild and domestic mammals. It causes skin disorders that may lead to severe generalized skin disease (mange). We investigated the spread and dynamics of sarcoptic mange in one of the best preserved carnivore communities in the Bia?owie?a Primeval Forest over the last 20 years. Sarcoptic mange was found in 6 of 10 investigated species. The highest percentage of infected individuals was recorded in red foxes (19 %), European badgers (9 %), grey wolves (7 %), raccoon dogs (6 %), and stone martens (5 %). Other species were not infected (least weasel, American mink, European polecat, pine marten) or infected sporadically (Eurasian lynx––1 case). Rate of infection was correlated with the sum of ecological and behavioral features, which may increase the spread of infection. Outbreaks of sarcoptic mange occurred simultaneously in several species of carnivores, which indicates the occurrence of between species transmission. We found that the source of investigated individuals (trapped, culled and found dead) may influence the results of the analysis. Our study shows that in carnivore communities such as in Bia?owie?a Forest, numerous species may serve as a reservoir of the pathogen and favor its persistence in the environment. This study indicates that sociality and use of den sites are important factors affecting sarcoptic mange spread and prevalence in wild populations of carnivores.     

Presence of Leishmania infantum in red foxes (Vulpes vulpes) in southern Italy

Skin, lymph node (popliteal), and bone marrow samples were collected from 50 red foxes (Vulpes vulpes) from May 2004 to May 2005 in southern Italy. Samples were tested for Leishmania infantum by polymerase chain reaction (PCR). The parasite was detected by PCR from 20 of 50 (40%) fox carcasses. All 20 positive cases were PCR-positive from lymph node and bone marrow samples, whereas 17 of 20 positive cases were PCR-positive from skin samples. Infection status was not related to age or sex. This is the first report of leishmaniasis in red foxes in Italy based on PCR results, and these results reinforce the assumption that this wild canid can serve as a reservoir for Leishmania.     

Experimental ivermectin treatment of sarcoptic mange and establishment of a mange-free population of Spanish ibex.

Ivermectin was used to treat sarcoptic mange in Spanish ibex (Capra pyrenaica hispanica). Its therapeutic effectiveness was analyzed when it was administered through subcutaneous injection, to sick animals in the consolidation stage of mange (third phase) and, with double injections to chronically affected animals (fourth phase) at a dosage of 0.2 or 0.4 mg/kg body weight (bw). Three wk after treatment, the animals in the third phase of mange treated with a high dose (0.4 mg/kg bw) of ivermectin were completely cured. The same result was achieved after 4 wk of treatment in those animals in phase 3 of mange when 0.2 mg/kg body weight was used. Double injection with ivermectin, even at high doses, did not guarantee the complete cure of all cases of sarcoptic mange in the chronic stage (phase 4); only three of six animals were free of Sarcoptes scabiei. The second experiment consisted on the application of a sanitation program in order to obtain a population of Spanish ibex free from S. scabiei, starting with free-ranging animals, some of them healthy and others sick. After capture the animals were classified as chronically ill, in which case they were excluded from the program, mite carriers and healthy specimens. All the animals were treated first topically with foxim (500 mg/l) and subcutaneously with ivermectin (0.4 mg/kg bw). The infected animals were housed in the treatment pen, and received two doses of ivermectin (0.2 mg/kg bw) at an interval of 15 days, then spent 15 days in the quarantine pen, where they received a further dose before they were included in the pool of healthy animals, and immediately were placed in the quarantine phase. The sanitation we implemented was fully effective in curing the affliction of Spanish ibex affected by S. scabiei.     

The impact of sarcoptic mange Sarcoptes scabiei on the British fox Vulpes vulpes population

• 1 Disease epizootics can significantly influence host population dynamics and the structure and functioning of ecological communities. Sarcoptic mange Sarcoptes scabiei has dramatically reduced red fox populations Vulpes vulpes in several countries, including Britain, although impacts on demographic processes are poorly understood. We review the literature on the impact of mange on red fox populations, assess its current distribution in Britain through a questionnaire survey and present new data on resultant demographic changes in foxes in Bristol, UK.
• 2 A mange epizootic in Sweden spread across the entire country in < 10 years resulting in a decline in fox density of up to 95%; density remained lowered for 15–20 years. In Spain, mange has been enzootic for > 75 years and is widely distributed; mange presence was negatively correlated with habitat quality.
• 3 Localized outbreaks have occurred sporadically in Britain during the last 100 years. The most recent large‐scale outbreak arose in the 1990s, although mange has been present in south London and surrounding environs since the 1940s. The questionnaire survey indicated that mange was broadly distributed across Britain, but areas of perceived high prevalence (> 50% affected) were mainly in central and southern England. Habitat type did not significantly affect the presence/absence of mange or perceived prevalence rates. Subjective assessments suggested that populations take 15–20 years to recover.
• 4 Mange appeared in Bristol's foxes in 1994. During the epizootic phase (1994–95), mange spread through the city at a rate of 0.6–0.9 km/month, with a rise in infection in domestic dogs Canis familiaris c. 1–2 months later. Juvenile and adult fox mortality increased and the proportion of females that reproduced declined but litter size was unaffected. Population density declined by > 95%.
• 5 In the enzootic phase (1996–present), mange was the most significant mortality factor. Juvenile mortality was significantly higher than in the pre‐mange period, and the number of juveniles classified as dispersers declined. Mange infection reduced the reproductive potential of males and females: females with advanced mange did not breed; severely infected males failed to undergo spermatogenesis. In 2004, Bristol fox population density was only 15% of that in 1994.

     

The effects of red fox Vulpes vulpes faecal odours on the feeding behaviour of Orkney voles Microtus arvalis

Orkney voles Microtus arvalis show avoidance of red fox Vulpes vulpes faecal odours, both in the laboratory and in the wild. Since these voles have been isolated from foxes since Neolithic times it is likely that these responses are innate rather than learned.
When applied to young Scots pine saplings, the fox odour inhibited feeding by voles when alternative foods were available.     

Comparative pathological and immunohistochemical features of sarcoptic mange in five sympatric wildlife species in Northern Spain

This study collects pathological information concerning sarcoptic mange in sympatric red deer, roe deer, chamois, wolf and red fox from Northern Spain, and discusses reported variations in the response from the different species against Sarcoptes scabiei. Wolf is the only studied species which shows prevalence of the hypersensitivity (alopecic) response to the detriment of the hyperkeratotic form, usually observed in ungulates and fox. The present work shows the use of immunohistochemistry as a valuable tool for the study and diagnosis of sarcoptic mange in those species whose immune response or stage of infestation limits the number of detectable mites, not an unusual difficulty faced when working with sarcoptic mange in wildlife species.     

Survival and Cause-Specific Mortality of Red Foxes in Agricultural and Urban Areas of Illinois

Abstract: Range expansion and population increase by coyotes (Canis latrans), reduced hunting and trapping, and intensified agricultural practices in the Midwest have altered red fox (Vulpes vulpes) mortality, although relative impacts of these factors are unknown. We examined mortality causes and survival of red foxes in urban and rural agricultural areas of Illinois, using radio telemetry data from 335 foxes (Nov 1996 to May 2002). We used Akaike's Information Criterion to evaluate six survival models for foxes reflecting 1) environmental effects, 2) intrinsic effects, 3) temporal effects, 4) behavioral effects, 5) social effects, and 6) a global model. Environmental and intrinsic models of survival were optimal for adult foxes. Adult foxes with low (0-20%) and high (80-100%) percentages of row crops in their home ranges had higher survival than adults with moderate percentages (40-70%). Heavier adults at capture also survived better. A global model (all covariates) was optimal for juvenile foxes. Higher juvenile survival associated with larger litters, lower body fat, and reduced dispersal time. Yearly survival ranged from 0.18 for rural male juveniles to 0.44 for rural female adults. Adult survival rates (0.35) were 11% higher than juvenile survival rates (0.24). Yearly survival varied for urban foxes due to cyclic outbreaks of sarcoptic mange (Sarcoptes scabei). Thus, summer survival (May-Sep) of urban juveniles ranged from 0.10 (mange present) to 0.83 (no mange recorded). Mange was the most common (45% of all fatalities) source of mortality for urban foxes, followed by road kill (31%). We recorded only 4 mange fatalities (2%) for rural foxes. Rural foxes experienced low hunting mortality (7%) and equivalent road kill and coyote predation fatalities (40% each). Sources of mortality for midwestern foxes have dramatically changed since the 1970s when hunting was the major cause of mortality. Coyote predation has effectively replaced hunting mortality, and cyclic patterns of mange outbreaks in urban fox populations might indicate a dynamic source or sink relationship to surrounding rural fox populations. Absent mange, urban areas might provide refugia for red foxes where coyote populations persist at high densities in rural areas. Managers of sympatric urban and rural wildlife populations must understand survival dynamics influencing the population at the landscape level.