Rabies in urban foxes (Vulpes vulpes) in Britain: the use of a spatial stochastic simulation model to examine the pattern of spread and evaluate the efficacy of different control régimes.

The threat of rabies being reintroduced into Britain is probably greater now than at any time over the last 60 years. This threat is reviewed with particular regard to the problems that would be posed should rabies be introduced to the high-density fox populations found in many cities in southern England. Computer models can provide a valuable means of understanding the pattern of rabies spread in fox populations and the likely problems of control, so the construction of previous rabies models was reviewed. None were found to be suitable for analysing the particular problems posed by high-density, spatially heterogeneous, urban fox populations. Therefore, a new spatial stochastic simulation model was produced, based on demographic and other data collected during a long-term study on the urban fox population in Bristol, and fox density data collected from a number of cities in southern England. The simulation model was used to analyse the effects of spatial heterogeneity in the fox population on the pattern of rabies spread. Simulations were then used to evaluate the effects of: (i) varying levels of fox control; (ii) changing the size of the control zone; (iii) the onset of the rabies epizooty at different times of the year: and (iv) delay before the commencement of control on the chances of containing the disease. These simulations were run for four cities (Bournemouth and Poole, Bristol, Leicester and the West Midlands conurbation) with different mean fox population densities. It was found that the variance in the monthly velocity of the rabies front was greater for heterogeneous fox populations. In cities with high fox densities, low or moderate levels of control were unsuccessful in containing the disease, but these urban areas had the highest rates of success with the highest levels of control. A three-month delay in the commencement of a rabies control campaign on average reduced the chance of successfully controlling the disease by 10-20%, although this was higher in lower-density fox populations. Rabies outbreaks in the dispersal period were on average 10% less likely to be contained. Increasing the size of the control zone increased the chances of successfully containing the disease, although this effect was density dependent, so the effect was less in low-density fox populations. These results are discussed in relation to the current rabies contingency plans for British urban areas.     

一种新的人兽共患传染病——狐狸阴道加德纳氏菌病的研究 Ⅲ.流行病学调查

对国内主要狐场狐狸阴道加德纳氏菌病的流行病学调查表明,银黑狐、北极狐、赤狐及彩狐均对本病易感染,主要通过交配传染,病狐在本病流行中起主要作用.各狐场感染率为0.9—21.9%,导致流产率1.5—14.7%,空怀率3.2—47.5%,揭示了本病的严重危害性.通过血清学和病原分离证实,本病可感染饲养管理人员,为人兽共患病.除狐狸外,貉、水貂及犬也可感染.实验动物中小白鼠、大白鼠、地鼠、豚鼠和家兔对本病不感染.     

Hereditary hypophosphatemic rickets with hypercalciuria is caused by mutations in the sodium-phosphate cotransporter gene SLC34A3

Hypophosphatemia due to isolated renal phosphate wasting results from a heterogeneous group of disorders. Hereditary hypophosphatemic rickets with hypercalciuria (HHRH) is an autosomal recessive form that is characterized by reduced renal phosphate reabsorption, hypophosphatemia, and rickets. It can be distinguished from other forms of hypophosphatemia by increased serum levels of 1,25-dihydroxyvitamin D resulting in hypercalciuria. Using SNP array genotyping, we mapped the disease locus in two consanguineous families to the end of the long arm of chromosome 9. The candidate region contained a sodium-phosphate cotransporter gene, SLC34A3, which has been shown to be expressed in proximal tubulus cells. Sequencing of this gene revealed disease-associated mutations in five families, including two frameshift and one splice-site mutation. Loss of function of the SLC34A3 protein presumably results in a primary renal tubular defect and is compatible with the HHRH phenotype. We also show that the phosphaturic factor FGF23 (fibroblast growth factor 23), which is increased in X-linked hypophosphatemic rickets and carries activating mutations in autosomal dominant hypophosphatemic rickets, is at normal or low-normal serum levels in the patients with HHRH, further supporting a primary renal defect. Identification of the gene mutated in a further form of hypophosphatemia adds to the understanding of phosphate homeostasis and may help to elucidate the interaction of the proteins involved in this pathway.     

Modeling control of rabies outbreaks in red fox populations to evaluate culling,vaccination, and vaccination combined with fertility control

A predictive model of spread and control of rabies in red fox (Vulpes vulpes) populations was used to evaluate efficacy of culling, oral vaccination, and oral vaccination and fertility control (V + FC) as rabies control strategies. In addition, effects of season, fox population density, and a delay in starting control were modeled. At fox densities of 0.5 fox families/km2 or greater, a single oral vaccination campaign with bait uptake rates of less than 50% resulted in ineffective rabies control. An uptake rate of at least 80% was required to give a better than 80% chance of eliminating rabies. Vaccination was least effective at controlling rabies if applied 1 or 2 mo before the foxes gave birth. Seasonal timing of poison or V + FC had little effect on efficacy, which was always more successful than the oral vaccination alone. The longer the delay between the simulated start of the rabies infection and the application of a single vaccination campaign, the less successful was the control, particularly at the higher fox densities tested. At a fox density of 0.25 families/km2, all the strategies were equally successful at eliminating rabies. At higher fox densities V + FC was slightly less successful than culling, whereas vaccination-only was considerably less successful. The sole use of vaccination is not considered a viable control method for areas with high fox densities. The model suggests that an area of culling centered on the disease focus, plus an outer ring of vaccine or V + FC, could be the best strategy to control a point-source wildlife rabies outbreak.     

Vitamin-D-deficient rickets in Manitoba, 1972-84.

Vitamin-D-deficient rickets still exists in children in Manitoba and adjacent areas. Between 1972 and 1984, 48 cases were documented at Winnipeg Children''s Hospital. The patients ranged in age from 1 to 49 months; 40 were Canadian natives (38 Indians and 2 Inuit), most of whom lived in the Island Lake area of northern Manitoba. Of the 48, 16 had clinical signs of rickets, 12 had tetany due to hypocalcemia and 38 had radiologic evidence of rickets. Hypocalcemia was found in 27, and hypophosphatemia in 19; hyperaminoaciduria was found in 7 of 20. All 48 had elevated serum alkaline phosphatase levels. In addition to rickets, 16 patients aged 12 months or more had evidence of malnutrition. Climate and lifestyle in northern areas of the Canadian midwest result in little or no biosynthesis of vitamin D by solar radiation; therefore, adequate dietary vitamin D intake is essential to prevent deficiency. The diets of pregnant women and infants in these areas are deficient in vitamin D. The authors recommend vitamin D supplements for all pregnant women and infants in areas of risk to eradicate this preventable disease.     

Bone mineral density of the spine and radius shaft in children with X-linked hypophosphatemic rickets (XLH)

X-linked hypophosphatemic rickets (XLH) is characterized by inadequate skeletal mineralization. The bone mineral density (BMD) of the radius shaft and the lumbar spine was determined in 13 children with XLH. Ten patients were on treatment, whereas three patients had discontinued treatment 20–32 months prior to this study. Two of them had radiological evidence of rickets.The radius shaft BMD was significantly diminished: Z score was −1.33 ± 0.89 (P < 0.001), while the BMD of lumbar spine was significantly augmented (Z score + 1.95 ± 1.17, P < 0.001). A positive correlation was found between the Z scores for the BMD of the radius shaft and spine. The two patients with overt rickets had lower radius shaft BMD values and a lesser increment of BMD of the spine. The BMD deficit of cortical bone may be related to the lack of efficacy of the treatment and/or to an intrinsic defect of the bone on this disease. On the other hand, the augmented BMD of the lumbar spine might reflect the overabundance of partially mineralized osteoid.The determination of the BMD of the radius shaft by SPA was a sensitive method for detecting abnormalities of the bone mass in XLH patients under treatment without radiological signs of rickets.     

X-Linked hypophosphatemic rickets: a disease often unknown to affected patients

X-Linked hypophosphatemic rickets (XLH) is an X-linked dominant disorder that is secondary to renal phosphate wasting. Affected individuals frequently present the following characteristics: short stature, lower-extremity deformity, bone pain, dental abscesses, en-thesopathy, rickets, and osteomalacia. Since the disorder is characterized by evident phenotypic abnormalities, we hypothesized that there would be a high degree of knowledge about the disease in affected kindreds. Thus, we constructed a six-page, self-administered questionnaire to determine whether family members are, in fact, aware of their disease and properly diagnosed and treated. We also designed the survey to determine rates of symptoms thought to be associated with rickets/osteomalacia in a population with a lower referral bias than is usually seen in tertiary care centers. We administered the questionnaire to 234 study subjects (57 affected) who were members of one of three large kindreds. Although 62% of affected individuals knew they had some problem with their bones, only 22.6% were told by a physician that they had rickets or osteomalacia. This apparent lack of awareness occurred in spite of 61.1% of affected subjects complaining of bone or joint problems to their personal physician. Indeed, of those patients who had persistent complaints, only 34.5% were told they had rickets or osteomalacia. Only one patient was taking phosphate and vitamin D. The spectrum of symptoms evident in affected subjects compared with normals included: dental abscesses (54.5% vs. 13.0%, P < 0.001), bone pain (45.5% vs. 28.2%, P = 0.027), back pain (51.8% vs. 35.1%, P = 0.036), joint stiffness (48.2% vs. 16.8%, P < 0.001), joint pain (55.4% vs. 31.1%, P = 0.003), weakness (25.0% vs. 10.7%, P = 0.023), and hearing loss (28.6% vs. 9.8%, P = 0.002). Surprisingly, although affected individuals complained of many symptoms due to XLH, they fractured bones less frequently than controls (20% vs. 38.1%., P = 0.018). Our data demonstrate that, despite the presence of disease in family members, few affected subjects knew that they had XLH. Although the presence of symptoms did increase knowledge of disease status, only one-third of symptomatic individuals knew of their diagnosis.     

Lack of evidence of paratuberculosis in wild canids from Southwestern Europe

Wild carnivores are at the top of the trophic chain. They are predators and carrion consumers, and thus, prone to come in contact with disease agents contaminating the environment or infecting live or dead animals. We hypothesized that wild canids could be used as sentinels for the detection of regions with higher Mycobacterium avium paratuberculosis (MAP) prevalence in wild and domestic animals. To test this hypothesis, we set up an ELISA to test 262 wolf (Canis lupus) and fox (Vulpes vulpes) sera for MAP-specific antibodies and processed a subset of samples for culture (n = 61), MAP-specific PCR (15) and histopathology (14). In wolves, the optical density (OD) values in the ELISA were continuously distributed. Ten fox sera (4%) had OD readings of over twice the mean, suggesting contact with mycobacteria. However, all samples tested by PCR were negative for both IS900 and ISMAP02 sequences, and samples cultured for MAP yielded no growth. No visible paratuberculosis or tuberculosis-compatible lesions were recorded. On histopathological examination, no lesions compatible with mycobacterial diseases were observed. These results suggest that wild canids show little or no evidence of paratuberculosis and are unlikely to be useful sentinels for the detection of MAP in Southwestern Europe.

     

Dynamics of spatial relationships among members of a fox group (Vulpes vulpes: Mammalia: Carnivora)

The 'Resources Dispersion Hypothesis' (RDH, Macdonald, 1983) suggests that, for solitary foragers such as the red fox Vulpes vulpes , group formation is dependent on resource distribution heterogeneity. Our data are compatible with this hypothesis. Rodents, which constituted the main fox prey, were heterogeneously distributed in time and space. Six foxes (three males and three females) were radiotracked continuously from February 1989 to October 1990 (20 months) and we observed spatial sharing between one male and two or three females, considered as members of a 'spatial group'. Even though their home ranges overlapped between 30 and 100%, members of the group foraged alone and had very few contacts with conspecifics during the night. Furthermore, they partitioned the common home range so that each fox made exclusive use of foraging patches. In contrast, during the daytime, two to four members of the group were frequently in association in a communal resting place. Such associations were observed all year round; they were durable and dynamic. Their advantages were examined. We suggest that they play a role in the maintenance of social cohesion within the group in providing the opportunity for direct contact between foxes. They might also permit increased security through mutual vigilance during resting.     

Systemic AA amyloidosis in the red fox (Vulpes vulpes)

Amyloid A (AA) amyloidosis occurs spontaneously in many mammals and birds, but the prevalence varies considerably among different species, and even among subgroups of the same species. The Blue fox and the Gray fox seem to be resistant to the development of AA amyloidosis, while Island foxes have a high prevalence of the disease. Herein, we report on the identification of AA amyloidosis in the Red fox (Vulpes vulpes). Edman degradation and tandem MS analysis of proteolyzed amyloid protein revealed that the amyloid partly was composed of full‐length SAA. Its amino acid sequence was determined and found to consist of 111 amino acid residues. Based on inter‐species sequence comparisons we found four residue exchanges (Ser31, Lys63, Leu71, Lys72) between the Red and Blue fox SAAs. Lys63 seems unique to the Red fox SAA. We found no obvious explanation to how these exchanges might correlate with the reported differences in SAA amyloidogenicity. Furthermore, in contrast to fibrils from many other mammalian species, the isolated amyloid fibrils from Red fox did not seed AA amyloidosis in a mouse model.     

On the spatial spread of rabies among foxes

We present a simple model for the spatial spread of rabies among foxes and use it to quantify its progress in England if rabies were introduced. The model is based on the known ecology of fox behaviour and on the assumption that the main vector for the spread of the disease is the rabid fox. Known data and facts are used to determine real parameter values involved in the model. We calculate the speed of propagation of the epizootic front, the threshold for the existence of an epidemic, the period and distance apart of the subsequent cyclical epidemics which follow the main front, and finally we quantify a means for control of the spatial spread of the disease. By way of illustration we use the model to determine the progress of rabies up through the southern part of England if it were introduced near Southampton. Estimates for the current fox density in England were used in the simulations. These suggest that the disease would reach Manchester within about 3.5 years, moving at speeds as high as 100 km per year in the central region. The model further indicates that although it might seem that the disease had disappeared after the wave had passed it would reappear in the south of England after just over 6 years and at periodic times after that. We consider the possibility of stopping the spread of the disease by creating a rabies 'break' ahead of the front through vaccination to reduce the population to a level below the threshold for an epidemic to exist. Based on parameter values relevant to England, we estimate its minimum width to be about 15 km. The model suggests that vaccination has considerable advantages over severe culling.     

Case studies of the history and politics of wild canid restoration in Korea

Wild canids were historically abundant in Korea; however, the gray wolf, dhole, and red fox were extirpated during the twentieth century. The causes varied. “Pest control” during the Japanese occupation, ecological destruction during wars, disease epizootics, and “vermin control” after the Korean War contributed to the complete demise of wolves. The fox had succumbed to unregulated hunting, rodenticides, habitat loss, and disease epizootics. The dhole was naturally rare; its extirpation from northeastern Asia including Korea is not established. Although the wolf and fox are extirpated, the Korean government still lists both as endangered species to facilitate the recently implemented restoration programs. Restoration will face the challenges of importing genetically diverse populations and the critical loss, fragmentation, and alteration of peri‐urban habitats. The overall social support for these efforts is not clear: it may be low because of changes in social mores or simply an unintended consequence of land and water use choices and policies that people may not perceive in everyday life. In this critical analysis, we postulate that the current restoration programs are misdirected toward inappropriate species and likely employ outdated techniques. We propose that a reallocation of restoration efforts and resources to populations of existing rare or threatened species would be more ecologically beneficial with higher probabilities of success. We recognize that there can be good reason to restore the upper trophic levels, especially keystone species, but are concerned that the impetus is more about focusing on charismatic megafauna rather than pragmatic choices more likely to be effective.     

Screening Rastafarian children for nutritional rickets.

We examined 42 Rastafarian children under 5 years of age who were registered with a single inner city general practice to determine the prevalence of nutritional rickets. Twenty children were receiving a strict vegan(I-tal) diet and were considered to be at high risk of developing rickets and were referred for biochemical and radiological investigation. Seven of 20 children investigated had rickets, giving an overall prevalence of 7/42. Treatment with oral cholecalciferol was successful in all seven children. Fourteen out of 18 children had evidence of iron deficiency, with low haemoglobin concentrations and hypochromic-microcytic blood films. Before this study Rastafarian children rarely attended the well baby clinic, received no vitamin supplements, and few had been immunised. They now regularly attend the clinic, receive vitamin and iron supplements, and all have completed primary immunisation.     

Leishmaniosis due to Leishmania infantum in a FIV and FelV positive cat with a squamous cell carcinoma diagnosed with histological, serological and isoenzymatic methods

Leishmaniosis caused by Leishmania infantum is an endemic zoonosis present in the Mediterranean area. Canidae (dog and fox) constitute the main reservoir hosts for the parasite, whilst wild rodents or the cat can be carriers of the protozoan and are considered as secondary potential reservoirs. This paper describes a case of disseminated feline leishmaniosis with cutaneous (ulcerative), visceral (spleen and lymph nodes) and blood involvement in a FIV-FelV positive cat. The microscopic identification of the Leishmania infection was initially made on a skin biopsy of the temporal area, where a squamous cell carcinoma was diagnosed. The diagnosis of the disease was achieved by several serological techniques (ELISA, IFAT and Western-blot). The strain was obtained by blood culture, characterized by electrophoresis of isoenzymes and identified as Leishmania infantum zymodeme MON-1. Since the infection due to L. infantum is a zoonosis, the potential feline reservoir should be more investigated. Serological analysis by Western blot on domestic cats provides a useful tool. In veterinary practice, feline leishmaniosis should be systematically included in the differential diagnosis when compatible cutaneous lesions are present, especially in the endemic areas of canine leishmaniosis.     

The history of resistant rickets: A model for understanding the growth of biomedical knowledge

Two essential periods may be identified in the early stages of the history of vitamin D-resistant rickets. The first was the period during which a very well known deficiency disease, rickets, acquired a scientific status: this required the development of unifying principles to confer upon the newly developing science of pathology a doctrine without which it would have been condemned to remain a collection of unrelated facts with very little practical application. One first such unifying principle was provided by the notion of hygiene; while the blanket explanations provided by this notion alone were much too general to enable rickets to achieve scientific status, it did point out the need to look for specific external causes for the disease and to examine the life-style and dietary habits of the patients. The second phase of the conceptualization of the disease was the assumption of a specific cause — that is, using concepts developed in the area of infectious diseases. This was made possible by fundamental similarities between deficiency and infectious diseases, in spite of their apparent differences. Both types of illness have some of the characteristics of what Georges Canguilhem calls the ontological representation of disease⁷⁷ as opposed to dysharmonic representations, which primarily concern the endocrine diseases. It is precisely this shift from one to the other manner of perceiving ill health that enabled the identification of the vitamin D-resistant rickets. Conceptualization of the notion of vitamin D resistancy required that the conditions causing the disease be looked for within the organism rather than outside it; this was thus the first time that endocrine concepts were applied to studying the physiology of vitamin D.The history of resistant rickets therefore represents an interesting model for understanding the growth of biomedical knowledge. It allows the development of a number of more general ideas on the question of the relationship between biology and medicine and on the thorny problem of specificity in medical thinking. As far as this topic is concerned it can be seen that there was an ongoing exchange between medical and biological thinking during the initial period up until 1937, and that one could deny any such specificity in medical thinking during this same period. Albright, for example, used human diseases as spontaneously produced models for experimental biology. It was also more feasible for an experimental biologist to administer toxic doses than for a clinician to do so.     

赤狐线粒体全基因组及系统发育分析

测定了赤狐的线粒体基因组全序列,总长度为16 723 bp,碱基组成为：31.3% A、26.1% C、14.8% G、27.8% T。和大多数哺乳动物一样,赤狐的线粒体全基因组包含13个蛋白质编码基因、2个核糖体RNA基因、22个转运RNA基因和1个控制区。除ND3基因起始密码子为不常见的ATT外,赤狐与北极狐、狼、家犬、郊狼的线粒体蛋白质编码遵循相同模式。在控制区的保守序列区段1和2之间发现一段较长的富含AC的随机重复序列。为了验证赤狐与其他犬科动物的系统发育关系,利用12个重链蛋白质编码基因,分别通过邻接法和最大简约法构建了系统发育树。结果表明：赤狐与北极狐是姐妹群,它们在犬科中都属于赤狐型分支,而灰狼、家犬和郊狼则属于狼型分支,与现有的系统进化研究结果一致。     

内蒙古达赉湖地区赤狐生境选择及生境景观特征分析

近年来,干旱、鼠害及人为对草原的过度开发利用等对达赉湖地区赤狐的数量及分布范围造成了很大影响。借助于主成分分析、Bailey’s判别分析、遥感和地理信息系统对达赉湖自然保护区赤狐的生境选择及生境的景观特征进行了研究。在赤狐家域内采用样线法和样方法,共设置10 m×10 m样方245个(实验样方101个,对照样方144个),并测定样方内的7个生境因子:植被类型、隐蔽级、食物丰富度、雪深、距水源距离、距围栏距离、距居民点距离。对样方内数据进行主成分分析得出,食物和隐蔽性是赤狐生境选择的主要因子,距居民点距离和距围栏距离是赤狐生境选择的次要因子,雪深和距水源距离是赤狐在生境选择中未表现出选择和利用的因子。利用Bailey’s方法和基于赤狐的生境分布图的景观统计得出:赤狐偏好选择柳灌丛和芦苇塘两种生境,这两种生境的总面积约为1093.47 km2,占研究区总面积的14.05%;赤狐随机利用河道、典型草原和草甸草原3种生境类型,这3种生境的总面积约为4721.79 km2,占研究区总面积的60.67%。;回避的生境为冰面和沙化草地,总面积约为1968.09 km2,占研究区总面积的25.29%。基于地理信息系统和Fragstats的景观特征分析得出,赤狐最适宜生境的面积最少,斑块数量最多,平均斑块面积最小,平均形状指数最小,平均斑块距离最大;其次是较适宜生境和不适宜生境;一般适宜生境的面积最多,斑块数量最少,平均斑块面积和平均形状指数最大,平均斑块距离最小。赤狐多分布于斑块较大的适宜其生存的生境或分布于由这些斑块形成的生境斑块镶嵌体中。     

Skeletal manifestations of rickets in infants and young children in a historic population from England

Gross and radiographic changes characteristic of inadequate bone mineralization due to rickets are described in 21 immature skeletons from a 19th century urban population from Birmingham, England. The aims of the study are as follows: to evaluate and if possible augment existing dry-bone criteria for the recognition of rickets in immature skeletal remains; to investigate the value of radiography for the paleopathological diagnosis of rickets; and to compare and contrast the expression of rickets in this group with that previously documented for a rural agrarian population from Wharram Percy, England. Some gross skeletal signs of rickets which were not previously well-documented in paleopathological studies are noted. The worth of radiography for evaluating structural changes to both cortical and trabecular bone in the disease is demonstrated, and features useful for the interpretation of vitamin D deficiency are discussed. The pattern of skeletal elements affected and the severity of changes differs in the Birmingham group from that seen in the comparative rural population. It is emphasized that a variety of factors may influence the expression of rickets in paleopathological material, including rate of skeletal growth, age cohort affected, and intensity of vitamin D deficiency. Nevertheless, careful analysis, not only of the frequency of rickets but also of the degree of severity of lesions and the patterning with respect to skeletal elements affected, may enable more nuanced understanding of the biocultural context of the disease in earlier populations.     

Adiaspiromycosis in large free living carnivores

Adiaspiromycosis was identified in 6 animals in the examination of the lungs of 90 large carnivores. Emmonsia crescens (Chrysosporium parvum var. crescens) was demonstrated as the causative agent in 5 cases of disease — in the badger (Meles meles), the otter (Lutra lutra) and the fox (Vulpes vulpes). E. parva was demonstrated in the remaining case of disease in a fox. The badger is a new, up to the present unknown host of E. crescens. The sporadic occurrence of adiaspiromycosis in the fox and the otter classifies this disease among rare diseases of these animals.     

Infectious canine hepatitis in a gray fox (Urocyon cinereoargenteus)

A free-ranging adult male gray fox (Urocyon cinereoargenteus) with moderate diarrhea and thick ocular mucus discharge was examined postmortem. Microscopically, the fox had intranuclear inclusion bodies within hepatocytes. Canine adenovirus-1 was identified by polymerase chain reaction (PCR) and nucleotide sequencing. To our knowledge, this is the first report of clinical infectious canine hepatitis in a gray fox.