Canidae Flashcards
Describe the general natural history and geographic distribution of canids.
Give the scientific name for the following species:
Bat-Eared Fox
Channel Island Fox
Grey Fox
Arctic Fox
Red Fox
Fennec Fox
Dhole
Coyote
Gray Wolf
Red Wolf
African Wild Dog
Maned Wolf
GENERAL BIOLOGY (Fowler 8)
- 35 species of dogs, wolves, coyotes, jackals, and foxes
- Domestic dog derived from the gray wolf through close association
- At least one wild species present on each continent, except Antarctica
- Red fox and gray wolf have some of the largest geographic ranges
- 1 kg to 60 kg
- Sexual dimorphism occurs in many species, with males being larger
- Range from solitary to pack animals
Describe the unique anatomy of canids.
What is teh dental formula of canids? What are teh carnassial teeth?
What is the primary heat loss mechanism for canids?
What is teh function of the supracaudal gland?
What type of placentation do canids have?
UNIQUE ANATOMIC FEATURES (Fowler 8)
- Medial position of the internal carotid artery btw entotympanic and petrosal arteries, loss of stapedial artery, and inflated entotympanic bulla divided by a partial septum
- Insertion point of the digastric muscle is widened in several taxa, forming a subangular lobe on the horizontal ramus of the mandible
- Rapid jaw movement
- Prominent in foxes with complex molars and raccoon dogs
- Dental formula: (I) 3/3, (C) 1/1, (P) 4/4, (M) 2/2
- Maxillary fourth premolar and mandibular first molar are modified to oppose each other (carnassial or sectorial teeth)
- Lateral nasal glands provide moisture for evaporative cooling during panting
- primary heat loss mechanism
- Sweat glands only present in footpads
- Seasonal molt of pelage helps to cope with temperature extremes
- Four digits in hindlimbs, 5 in each of the forelimbs
- Refined senses of hearing, smell, and vision
- Olfactory cues from urine, feces, and anal glands important in social interaction
- Supracaudal gland (tail gland): specialized scent gland located on the dorsal surface of the tail
- Located at 7-9 caudal vertebrae; most developed in solitary fox species
- Raccoon dog may undergo period of seasonal torpor
- Decreased BMR, lower levels of cortisol, insulin, and thyroid hormones
- African wild dog lacks variation at the major histocompatibility complex (MHC)
Unique features (Terio Zoo Path)
- Canids
- Most have dental formula I 3/3 C 1/1 P 4/4 M2/3
- All males have os penis
- Placenta is zonary and circumferential; circumferential marginal hematomas are a normal feature. Histologically labyrinthine and endotheliochorial
Describe the ideal housing of canids.
How do social dynamics need to be considered?
What escape precautions need to be considered?
What about breeding?
SPECIAL HOUSING REQUIREMENTS (Fowler 8)
- Allow for social species housed in groups to separate themselves in cases of aggression
- Should not have sharp corners; may result in traumatic injuries, inescapability from aggressors
- Keep in mind they are proficient diggers and skilled jumpers
- Dig barriers
- Height of 8 ft is recommended for most large canids
- Periparturient dam should have multiple choices of warm and dry whelping boxes
Describe your preventative medicine protocol for canids.
What preventatives should be considered?
What vaccines should be considered?
Describe your choice of vaccine products.
PREVENTATIVE MEASURES (Fowler 8)
- Consider heartworm preventative
- Vaccines (Table 46-6) based on geographic location
- Rabies, distemper, and parvo are considered core
- Many prefer monovalent products over multivalent
- Used modified live vaccines with caution
- Genetically modified canary-pox vectored vaccines are a safe alternative and are commonly used (cannot induce disease)
Describe the physical restriant of canids.
What techniques are used for small canids? What about larger ones?
What is a common complication in canid restraint? How is it managed?
RESTRAINT AND HANDLING (Fowler 8)
- Manual restraint in small canids
- Watch muzzles for normal breathing and avoidance of hyperthermia
- Hyperthermia commonly seen in restrained canids
- Body temps reaching 104
- Treat with IV cool fluids, cool slowly, sedatives
- Larger canids (maned wolves, gray and red wolves) may be restrained using catch poles or Y shaped padded poles
- Animals often cower when approached
- Limited exams, U/S, blood collection, vaccination, or administration of IV injection
- Box traps vs. foot traps vs. tranquilizer traps
- Table 46-2: anesthetic protocols
- Telazol: wide safety margin, however dose-dependent, prolonged, and rough recoveries are common
- Ketamine + alpha 2 agonist: reversibility, but have concerns of spontaneous arousal and hypertension
Describe anesthesia of nondomestic canids.
What sites are used for vascular access?
What are some common complications with anesthesia in canids? How are they managed?
What considerations need to be made for field anesthesia?
What considerations are made for pack reintroductions?
Vascular access
- Comparable with domestic dogs
- Jugular, cephalic, lateral saphenous
Intubation
- Not always essential, bt should be performed during prolonged procedures
Pre-anesthetic considerations
- Respiratory depression is common, supplemental oxygen and/or intubation should be available
- Prolonged exertion can result in hyperthermia–cooling measures should be available
- Hypothermia occasionally occurs under cold conditions and/or prolonged immobilizations
- Hypertension can occur with ketamine/alpha2 combos
- Anticholinergics should be used sparingly to avoid exacerbating hypertension
- Vomiting can occur–fast prior to anesthesia when possible
- Seizures can occur with dissociatives but less commonly when given with benzos
- Gastric dilation (and rarely GDV) can occur
Drug choice
- Drug choice varies by species and situation
- Mask induction or chamber induction also sometimes possible
- Can become overheated in induction chambers
- Isoflurane can be used for maintenance
- For routine procedures on young healthy animals in a controlled environment, they recommend medetomidine/butorphanol
- Should not be used for more invasive procedures
- May need to add ketamine or midazolam depending on depth and working time
- In emergency or uncontrolled situations, telazol or ketamine/medetomidine are recommended
- If animal is ill or old, probably not advisable to use an alpha 2
Field immobilization considerations
- Many species are nocturnal
- Often trapped and then injected, but darting also occurs
- Darting from helicopter or car can be done but has a higher risk of inaccuracy and trauma
Post-anesthetic challenges
- Most canids are pack animals, reintroduction after prolonged separation can result in fighting
- Animals should be kept with the pack as much as possible
Describe the most common surgeries of canids.
What types of closures should be used?
What has been associated with GDV in nondomestic canids?
SURGERY (Fowler 8)
- Repair of lacerations or traumatic wounds
- Dehiscence of body wall has been frequently seen after abdominal surgeries, may cannibalize their own surgical organs
- Simple interrupted is preferred to close abdominal wall
- Subcuticular skin closure
- Social species like bushdogs and wild dogs may experience increased anxiety isolated postop
- May not be allowed back into a social group
- Reintegration too soon may lead to excessive grooming, licking, or biting at the incision site
- Cystotomy for cystinuria in maned wolves
- GDV and GD has been documented: often found on necropsy
- Feeding an animal shortly after anesthesia anecdotally linked to GDV
- OVH and castration often performed
- Vasectomy has been documented in bushdogs
What is the etiologic agent of canine infectious hepatitis?
What species are susceptible?
What are the typical gross lesions associated with this disease?
What histologic lesions? What are the inclusion bodies?
- Canine adenovirus type 1 (Canine infectious hepatitis virus)
- Causes disease in a wide variety of canids and bears
- Gross lesions include petechial and ecchymotic hemorrhages of serosal surfaces, lymph node and gall bladder edema, and mottled fragile liver
- Intranuclear viral inclusion bodies which are acidophilic or basophilic are present in endothelial cells, hepatocytes, biliary epithelium and adrenal epithelium
What viral disease is a common cause of mortality in juvenile canids?
What are the typical clinical signs?
Describe vaccination strategies for this disease.
- Canine parvovirus
- Well documented in coyotes and wolves
- Clinical disease similar to domestic dogs, mortality rates variable
- GI signs, leukopenia, etc
-
Canine parvovirus
- Likely factor in juvenile mortality
- Significant morbidity and mortality in captive animals
- Modified live vaccine has caused concerns, not recommended until protective titers are present after using a killed vaccine
What is the etiologic agent of pseudorabies?
How does it affect canids?
Does is affect other carnivores?
- Pseudorabies/aujesky’s disease – caused by suid herpesvirus 1
- “mad itch”
- Canids can be incidentally infected
- Non-suppurative encephalitis with intranuclear eosinophilic inclusions
- Can also infect a variety of bear species, but clinical disease is rare
Describe the clinical signs associated with papillomaviruses in canids.
What are the inclusion bodies like?
- Papillomaviruses
- Oral papilomatosis of coyotes is the most common
- Usually self limiting
- Papilliform to cauliflower like lesions with hyperplastic basal cell layer
- If inclusions are present they are intranuclear and basophilic
What is the tropism of Canine Distemper Virus?
What type of virus is this?
What are the clinical signs in affected canids?
What inclusion bodies are typically seen?
What are the classic histologic lesions of this disease?
How does this disease affect wild canids?
Describe vaccine selection in preventing this disease.
- Canine distemper (CDV)
- Epitheliotropic and neurotropic
- Respiratory, neuro, and cutaneous signs most common, but signs variable
- Acute lesions in non-domestic canids similar to those in domestic dogs – rhinitis with purulent nasal or occulonasal discharge and pneumonia are common
- Eosinophilic cytoplasmic viral inclusions are most commonly found in syncytia, macrophages and bronchiolar epithelium
- White matter demyelination is the hallmark (but not pathognomonic) nervous system lesion in CDV infections and may be multifocal or patchy; it tends to affect cerebellum most severely
- Grey matter lesions may occur throughout the CNS
- Nuclear or cytoplasmic eosinophilic inclusions will be present in astrocytes and neurons
- Hyperkeratosis of the footpads is the classic cutaneous lesion, but can also been seen on the nasal planum or hair skin
- May see diarrhea (+/- secondary cryptosporidium or E coli infections)
- Ursids have shown serologic evidence of CDV, with few clinical cases reported
- Vaccine induced CDV infections have been described in red pandas when modified live vaccine is used
-
Canine distemper virus (CDV)
- Natural epizootics occur in wild populations
- Periodic introduction and maintenance of virus in domestic dogs poses a threat to endangered species
- CDV infection has occurred in African wild dogs despite vaccination
- Vaccine induced CDV infection has occurred after use of modified live vaccine
What type of virus is the rabies virus?
How is this disease transmitted?
What are the two forms?
What are the classic lesions?
What type of inclusion bodies are present? Where are they most commonly present?
How is this disease confirmed?
This disease is a continued threat to what species of wild canids?
- Rabies
- Progressive encephalomyelitis that is typically lethal was signs are apparent
- Transmission via saliva or open wounds
- Dumb form and furious form
- Non-suppurative encephalomyelitis, ganglioneuritis, adrenalitis, sialoadenitis
- Lesions most severe from pons to hypothalamus and cervical spinal cord
- Intracytoplasmic eosinophilic viral inclusions in neurons (negri bodies)—most common in hippocampus
- Diagnosed off of fluorescent antibody test in unfixed samples of fresh brain including the medulla and cerebellum is most common, though PCR and DNA sequencing can provide confirmation
-
Rabies: lyssavirus in the rhabdovirus family
- Zoonotic
- Geographic reservoirs
- Continued epizootic threat to survival of Ethiopian wolf and African wild dog
- Oral vaccination of wildlife using recombinant vaccines is effective control strategy, or immunization with injectable killed rabies vaccine
What mycobacterium species affect canids?
How is this disease transmitted to them?
What lesions are usually present in affected canids?
- Mycobacterium
- M bovis/bovine tuberculosis – OIE reportable
- Granulomas and granulomatous inflammation of the LN, lungs, and other organs
- Typically a disease of ruminants but disease has been described in red foxes, gray foxes, coyotes, wolves, and fennec foxes as well as black bears
- Transmission through infected prey or carcases
- Granulomas with low numbers of acid fast positive bacilli, though disseminated infection with no gross or microscopic lesions has been reported in red foxes
- Other mycobacterial species have been reported in wild carnivores including M avium paratuberculosis in red foxes and coyotes, M avium avium in a jackal, M intracellulare and M kansasii in coyotes
- Gold standard for diagnosis is bacterial culture, though other methods are often needed
- M bovis/bovine tuberculosis – OIE reportable
What is the etiologic agent that causes anthrax?
How is this disease transmitted to canids?
What canid has a high seroprevalence?
What are the two main toxins of antrhax?
- Anthrax/Bacallus anthracis
- OIE reportable, large spore forming gram positive rod with clear capsule
- Disease most common in ruminants but can be seen in carnivores, likely through inhalation of spores from an infected carcass
- Proteins produced by the bacteria combine to produce edema toxin and lethal toxin which cause edema and death
- Serology of while black backed jackals shows high serum prevalence (95%), indicating high exposure and survival
What is the etiologic agent of lyme disease?
Clinical cases have been seen in what wild canid species?
- Borrelia/lyme
- Reported in a wild red fox – cutaneous erythema
What is the etiologic agent that causes Salmon poisoning?
How is it transmitted?
How are canids exposed?
Are other species also affected?
What are teh typical clinical signs and lesions?
-
Neorickettsia helminthoeca
- rickettsial organism that causes salmon poisoning
- Transmitted by Nanophyetus salmincola, an intestinal fluke of canids in NW US
- Infected via ingestion of fish or amphibians with encysted metacercariae
- Salmon poisoning/neorickettsia helminthoeca
- Reported in sun bears
- Rickettsial bacteria that infects the trematode nanophyetus salmincola – infected by eating a fish containing these trematodes
- Clinical signs include vomiting, diarrhea, lethargy
- Diagnosis of nanophyetus ova in feces allows a presumptive dagnosis
- Infected bears may develop eosinophilic gastritis and enteritis
What are the signs typically associated with dermatophytosis in nondomestic canids?
What histologic lesions are usually present?
What are the two main species of dermatophytes that affect canids?
- Dermatophytoses
- Alopecia and scaly skin with or without crusts
- Histo—accanthosis with orthokeratotic hyperkeratosis
- M canis and T mentagrophytes have been described in foxes
- M gypseum is an important cause of skin disease in red pandas
- Lesions on the tail, extremities, muzzle, and ears
- Typically during the warm season
What microsporidia have been documented to affect canids?
What species have been affected?
What lesions were found on necropsy?
- Microsporidia
- Encephalitozoon
- Rarely described in African wild dogs and a litter of arctic foxes
- Histo lesions seen in brain and kidney similar to that in E. cuniculi in rabbits
- Dissemination to other organs also seen in foxes
- Encephalitozoon
What are the four lungworms that affect nondomestic canids?
What are the typical lifecycles?
What species are affected by each of these worms?
Metazoa
- Oslerus osleri
- Dog lungworm, nematode, infests the trachea mainstem bronchi of canids
- Direct life cycle—larvae are hatched in resp tract, coughed up, swallowed, and shed via feces
- Ingestion of infected vomit is the primary mode of transmission
- Causes nodules within the tracheal mucosa
- Crenosoma vulpis
- Fox lungworm
- Foxes, wolves, raccoons and dogs are the definitive hosts
- Infection also reported in badgers, wolverines and black bears
- Adults reside in the trachea, bronchi, and bronchioles
- Larvae coughed up, swallowed, shed in feces – intermediate host is snails or slugs which are then eaten
- Gross lesions—parenchymal consolidation with intralesional adult nematodes
- Eucoleus aerophilus
- Another lungworm of wild carnivores including foxes
- Tends to infect higher in the resp tract than C vulpis
- Angiostrongylus
- Intravascular nematode with a wide host range including canids
- Indirect life cycle—ingestion of larvae from environment or infected gastropods
- A. vasorum aka French lungworm in canids and red pandas
- Adult worms reside in the right atrium and ventricle of the heart and pulmonary arteries
- A. gubernaculatus in island fox
- A. raillieti in crab eating fox
- Clinical signs include mild respiratory signs and thrombus formation
What two filaroid nematodes affect canids?
How are they transmitted?
What are teh typical clinical signs?
What species are affected?
- Dirofilaria immitis/heartworm disease
- Spirurid, filarial nematode
- Canids and felids are definitive hosts
- Other species including bears and red pandas can be infected
- Transmission by mosquito vector
- Pulmonary arteries and lungs
- Severe infections cause right sided CHF and PHT or caval syndrome
- Dirofilaria repens
- Subcutaneous and occasionally intrabdominal, LN or intestinal infections
- Foxes and wolves
- Can be zoonotic
Describe the lesions associated with Spirocerca infestation in canids.
What is the life cycle?
What clinical signs are seen in affected animals?
What can result from chronic infestation?
- Spirocerca lupi or S. artica
- Aortic aneurysm and/or fibrotic aortic and esophageal nodules
- reported in canids
- indirect life cycle – intermediate host is a beetle, paratenic hosts such as poultry, lizards, nad rodents
- infected animals may be asymptomatic or have coughing, weakness, lethargy, dysphagia or sudden death secondary to aneurysm rupture
- Chronic infection can also cause mural hyperplasia or neoplastic transformation (fibrosarcomaa or osteosarcoma)
What is the giant kidney worm?
What taxa are typically affected?
Are there any canids that are commonly affected?
How is it transmitted?
What are the associated clinical signs?
- Dioctophyma renale/giant kidney worm
- Primarily in mink and dogs but reported in wild canids
- Wolves, coyotes, jackals, foxes
- High prevalence in free-ranging maned wolves
- Ingestion of encysted larvae in infected raw fish, frogs, or annelid worms
- Largest known nematode to infect mammals
- Hematuria, ureteral obstruction and hydronephrosis
- Unilateral infections most common, right kidney usually affected
- Intraperitoneal parasites can be seen with aberrant migration
- Primarily in mink and dogs but reported in wild canids
What are the most common Trichinella species?
What animals are most commonly affected?
How is this disease transmitted? Can it be transmitted to people?
What are the typical lesions?
- Trichinella spp
- OIE reportable
- T spiralis most common, with T britovi, T pseudospiralis and T. nativa also reported
- Foxes, bears, and wolves most commonly infected
- Ovoviviparous nematodes
- Zoonotic transmission through consumption of undercooked meat (pork, bear)
- Myofiber necrosis with neutrophilic and eosinophilic inflammation
What is the etiologic agent of hepatozoonosis?
What canid species are commonly affected?
Describe the life cycle of this diease.
How is it transmitted?
What are the typical clinical signs?
What are the typical lesions?
- Hepatozoon
- Reported in jackalds, AWD, crab eating foxes, Pampas gray foxes, coyotes
- Life cycle: sexual development in definitive hosts (hematophagus arthropods) and asexual development in a vertebrate host
- Infection by ingestion of the arthropod or vertical transmission
- Clinical signs often absent, but lesions can include anemia or leukcytosis, pneumonia, myocarditis
- H canis has a characteristic “whell spoke” appearance with a central eosinophilic nucleus and peripheral, basophilic merozoites
- H americanum can cause severe segmental periosteal woven-bone production in canids
What it the most common mite to affect canids?
What are teh clinical signs?
What are the two forms of the disease?
- Sarcoptes scabiei
- Widespread, contagious, pruritic disease of numerous species of canids and ursids
- Hyperkeratotic and alopecic are the two most recognized form of the disease
- The first form generally occurs in naïve or immunocompromised individuals
- The second form is a hypersentivity reaction that develops in immunocompetent animals who mount a type I and type IV hypersensitivity reaction
- In addition to alopecia they develop intense dermal eosinophilic and mast cell infiltrates with few intralesional mites
What pentastomid has canids as their definitve host?
Where does infection usually occur?
What clinical signs may occur as a result?
- Pentastomids
- Called “tongue worms” due to appearance
- arthropods that infect the upper respiratory tract
- Nasal pentastomiasis due to Linguatula serrata occurs in canids as the definitive hosts
- Infection typically asymptomatic and found incidentally at necropsy, though URI signs can occur
Cystinuria is common in what canid species?
What are suspected causes of this disease?
What clinical signs may occur as a result?
- Cystinuria
- common in maned wolves
- autosomal recessive condition in humans and domestic dogs– defective transport of cystine across renal tubular epithelium
- dibasic aminoaciduria with excretion of cysteine and lysine
- meat based diet in captivity may predispose, but genetic component suspected
- Cystinuria: Maned wolves, likely genetic
- Often subclinical unless causing obstruction
- Monitor closely for stranguria
- Medical therapy aimed at affecting solubility of cysteine to prevent crystal precipitation
- Urine alkalinization
- Diet manipulation: reduce sodium intake and reducing protein from animal sources
Describe the reproduction of canids.
What type of reproductive cycle do most have?
How long is gestation typically?
What is average litter size for most canids? What species have unusually large litters?
What is pseudopregnancy? What pack members does this occur in?
REPRODUCTION (Fowler 8)
- Exceptionally long proestrous and diestrous phases
- Copulatory lock
- May be prolonged in species like the fennec fox
- Behavioral suppression of mating in subordinate young in a social group
- Obligate pseudopregnancy in subordinate females
- Pseudopregnancy: prolonged luteal phase following ovulation, may be as long as pregnancy
- Prepare subordinate females for rearing in a pack
- Most are seasonal breeders
A recent study evaluated the ocular anatomy and characteristics of crab-eating foxes.
What is the scientific name of the crab-eating fox?
What is unique about its pupil shape?
How does pupil shape correspond with natural history?
Renzo, R., Aldrovani, M., Crivelaro, R. M., Thiesen, R., de Barros Sobrinho, A. A., da Silveira, C. P. B., … & Laus, J. L. (2020). THE EYE OF CRAB-EATING FOX (CERDOCYON THOUS): ANATOMICAL CHARACTERISTICS AND NORMATIVE VALUES OF SELECTED DIAGNOSTIC TESTS, MORPHOMETRY OF CORNEAL TISSUE, AND ARRANGEMENTS OF CORNEAL STROMAL COLLAGEN FIBERS. Journal of Zoo and Wildlife Medicine, 51(2), 280-289.
Abstract: This study aimed to evaluate the ophthalmic parameters, morphometric features of corneal tissue, and arrangements of corneal stromal collagen fibers in crab-eating fox (Cerdocyon thous), a species of neotropical wild canid. We conducted the study on six juvenile crab-eating foxes (12 eyes), whilst 16 eyes were obtained post mortem from eight adult crab-eating foxes. The research was divided into two stages. In the first stage, eye anatomical characteristics, tear production (Schirmer 1 tear test, STT1), intraocular pressure (IOP), ocular echobiometry, and specular microscopy parameters related to morphology of corneal endothelium were studied in juvenile animals. In the second stage, morphometric features of corneal tissue (central corneal thickness [CCT] and corneal epithelium thickness) and arrangements of stromal collagen fibers were studied using eyes from adult animals. The main findings were that crab-eating fox eyes have vertical-slit pupils, holangiotic retina, and reference values (mean ± SD) of 13.37 ± 3.79 mm/min for STT1 and of 10.43 ± 3.84 mmHg for IOP. The ocular echobiometric features observed in crab-eating foxes are different from those reported for domestic dogs (Canis familiaris). Conversely, the corneal endothelial parameters are similar to those of domestic dogs. The CCT measured by tissue morphometry was 0.54 ± 0.06 mm, and the corneal epithelium thickness was 60.13 ± 8.71 µm. Mean coherency related to alignment of collagen fibers was 0.66 ± 0.12. The crab-eating fox cornea had predominantly thick collagen fibers. Crab-eating fox eyes have morphofunctional peculiarities. They resemble the eyes of domestic dogs in some aspects, but diverge in others.
- Key Points:
- Crab-eating fox (Cerdocyon thous) – Medium-sized carnivore, canidae.
- Widespread neotropical distribution.
- Corneal layers of the eye.
- Corneal epithelium protective interface with environment.
- Endothelium fundamental to corneal homeostasis, selective barrier vs fluid entrance into the stroma.
- Stroma determinant to transparency, shape, biomechanical properties of cornea, predominantly made of collagen fibers.
- Eye anatomical characteristics:
- Well-defined eyelashes on upper lid, superior and inferior lacrimal puncta, brown iris, vertical-slit pupil, nictitating membrane. Tapetum. Round optic disc.
- Vertical slit shaped pupil similar to European red foxes, different from domestic dogs and grey wolves.
- Facilitates stereopsis for estimating distances of object perched on the ground while enebling depth from blue to estimate distances along the ground.
- Vertical pupils usually characteristic of nocturnal or iurnal-nocturnal predators. Herbivores tend to have horizontal pupils and most diuranal predators have round pupils.
- Vertical slit shaped pupil similar to European red foxes, different from domestic dogs and grey wolves.
- Holangiotic retina with 3-4 spoke-like venules emerging from optic disc, numerous arterioles.
- Well-defined eyelashes on upper lid, superior and inferior lacrimal puncta, brown iris, vertical-slit pupil, nictitating membrane. Tapetum. Round optic disc.
- Diagnostic parameters:
- Mean STT, IOP for juvenile crab eating foxes lower vs domestic dogs and cats.
- Morphometry of corneal tissue:
- All had epithelium, stroma, endothelium. Similar to dogs.
- Epithelium had three layers – Stratum superficiale, stratum intermedium, stratum basale.
- Crab eating foxes had lower values of axial globe length, lens thickness, vitreous chamber depth. Anterior chamber depth similar to dogs and cats.
- CCT values of crab eating foxes determined by both noncontact specular microscopy and corneal tissue morphometry were lower than those reported for adult or juvenile domestic dogs studied with US pachymetry, confocal microscopy, or contact microscopy specular.
- Mean value of corneal thickness lower in foxes vs dogs and cats. Also had four to five cell rows vs six to nine in dogs and cats.
- Crab-eating fox (Cerdocyon thous) – Medium-sized carnivore, canidae.
- Takeaway: Crab eating fox differs from dogs in terms of pupil shape, STT, IOP, and ocular echobiometric and corneal morphometric features. Otherwise similar.
A recent study investigated the genetic characteristics of canine distemper viruses circulating in wildlife in the United States.
What type of virus is canine distemper?
What species are affected? What are the typical clinical signs?
How is it transmitted? What receptor does it bind to? How does it affect so many taxa?
What are the lineages that have been observed in the US traditionally?
Were new strains observed?
Are vaccines sufficient to contain these strains to reservoir populations?
Anis, E., Needle, D. B., Stevens, B., Yan, L., & Wilkes, R. P. (2020). Genetic characteristics of canine distemper viruses circulating in wildlife in the united states. Journal of Zoo and Wildlife Medicine, 50(4), 790-797.
Abstract: Canine distemper virus (CDV) is a highly contagious disease of wild and domestic mammals. Maintenance of CDV among wildlife plays an important role in the disease epidemiology. Wild animals, including raccoons (Procyon lotor) and gray foxes (Urocyon cinereoargenteus), serve as reservoirs of CDV and hamper the control of the disease. Recently, we discovered that at least three different CDV lineages (America-3 [Edomex], America-4, and America-5] that are genetically different from the available vaccine strains are circulating in domestic dogs in the United States. Because wildlife serve as a reservoir for the virus, it is important to determine if wildlife play a role in the maintenance and spread of these lineages. To determine the genetic characteristics of circulating strains of CDV in wildlife in various geographic regions in the United States, we studied the nucleotide sequences of the hemagglutinin (H) gene of 25 CDV strains detected in nondomestic species. The species included were free-ranging wildlife: three fishers (Martes pennanti), six foxes, one skunk (Mephitis mephitis), 10 raccoons, two wolves (Canis lupus), and one mink (Neovison vison). Strains from two species in managed care, one sloth (Choloepus didactylus) and one red panda (Ailurus fulgens), were also evaluated. Phylogenetic analysis of the H genes indicated that in addition to America-3, America-4, and America-5 lineages, there are at least two other lineages circulating in US wildlife. One of these includes CDV nucleotide sequences that grouped with that of a single CDV isolate previously detected in a raccoon from Rhode Island in 2012. The other lineage is independent and genetically distinct from other CDV strains included in the analysis. Additional genetically variable strains were detected, mainly in raccoons, suggesting that this species may be the host responsible for the genetic variability of newly detected strains in the domestic dog population.
- CDV – Morbillivirus, Paramyxoviriae, ssRNA virus.
- Detected in all families of terrestrial carnivores – Canidae, Felidae, Mustelidae, Ursidae, Vivveridae, Hyaenidae, Procyonidae. Multihost nature, unlike some other morbilliviruses i.e. measles.
- Respiratory, CNS, GI signs.
- High mortality in juveniles.
- Transmission via direct contact, air, bodily secretions, +/- fomites.
- Mutations affecting the viral signaling lymphocytic activation molecule SLAM receptor binding region affects the ability of the virus to infect new species.
- Maintenance within wildlife reservoirs between outbreaks hampers disease eradication and plays important role in epidemiology in domestic dogs.
- Six CDV sequences that were detected in fox, raccoon, red panda in SE grouped with America-5 lineage. Reported in domestic dogs.
- The red panda was a zoo animal, three other RPs died of distemper 1 month prior.
- Was vaccinated once with RECMBITEK vaccine, need multiple boosters for protection.
- Captive sloth from TN where another outbreak took place with American 4 lineage.
- Three nucleotide sequences grouped with American-3 (Edomex) lineage.
- Multiple CDV strains simultaneously circulating in domestic dogs and multiple wildlife species, adds to complexity of understanding epidemiology of CDV.
- Likely that raccoons are the source of ‘new’ genetic lineages.
- The red panda was a zoo animal, three other RPs died of distemper 1 month prior.
Takeaway: Recent rise in CDV cases in wildlife and detection of the same lineages circulating in domestic dogs suggests currently available vaccines are insufficient to keep these strains confined to reservoir populations. CDV distribution and epidemiology is complex.
A recent study investigated the effects of sarcoptic mange on endangered San Joaquin kit foxes.
What is the scientific name of the kit fox?
What wre the gross and histologic lesions associated with mange in these foxes?
What other comorbidities were seen? Are these seen in other species?
How does this differ from mange in red foxes?
What are some potential sources of exposure for these kit foxes?
Cypher, B. L., Rudd, J. L., Westall, T. L., Woods, L. W., Stephenson, N., Foley, J. E., … & Clifford, D. L. (2017). Sarcoptic mange in endangered kit foxes (Vulpes macrotis mutica): case histories, diagnoses, and implications for conservation. Journal of wildlife diseases, 53(1), 46-53.
Abstract: The San Joaquin kit fox (Vulpes macrotis mutica) is a federally endangered small carnivore whose distribution is limited to the San Joaquin Valley in central California. Population decline is due to profound habitat loss, and conservation of all remaining populations is critical. A robust urban population occurs in the city of Bakersfield. In spring of 2013, putative cases of mange were reported in this population. Mites from affected animals were confirmed to be Sarcoptes scabiei morphologically and by DNA sequencing. By the end of 2014, 15 cases of kit foxes with mange had been confirmed. As with other species, sarcoptic mange in kit foxes is characterized by intense pruritus and dermatitis, caused by mites burrowing into the epidermal layers, as well as alopecia, hyperkeratosis, and encrustations, secondary bacterial infections, and finally extreme morbidity and death.Of the 15 cases, six foxes were found dead, six were captured but died during attempted rehabilitation, and three were successfully treated. We have no evidence that untreated kit foxes can recover from mange. Sarcoptic mange constitutes a significant threat to the Bakersfield kit fox population and could pose an even greater threat to this imperiled species if it spreads to populations in nearby natural lands.
- San Joaquin kit fox federally endangered, threatened in CA. 3,000-5,000 left.
- Regional declines historically attributed to rabies and CDV.
- This study – describes outbreak of sarcoptic mange in spring 2013, Bakersfield CA.
- 15 cases of sarcoptic mange confirmed. 5 foxes found deceased, one humanely euthanized, 6 died within 3d of capture despite tx, 3 recovered with tx (selamectin).
- Gross lesions – moderate to severe sarcoptic mange with dermatitis, generalized alopecia with adherent crusts, excoriations, and lichenification on the head, neck, dorsum, extremities, and tail.
- Histo lesions – marked parakeratosis, acanthosis, intraepidermal pustules, serocellular crusts with intralesional mites and bacterial cocci.
- Comorbidities – dermal yeast infections, peritonitis, left testicular abscess, myocarditis, esophagitis, adrenal cortical hyperplasia, encephalitis negative for CDV and WNV, pneumonia, renal mineralization, glomerulonephritis, interstitial nephritis IHC negative for lepto, lymphadenopathy. Negative for rabies.
- 12 foxes positive for anticoagulant rodenticide exposure – brodifacoum, bromadiolone, chlorophacionone, difethialone, diphacinone.
- Sarcoptic mange confirmed in 15 cases with skin scrapes/PCR.
- S. scabiei commonly infects wild canids.
- In bobcats, can cause multi-organ changes consistent with dehydration, electrolyte dysregulation, severe protein loss across skin.
- Renal mineralization in kit foxes likely due to dehydration.
- In Italy, mange assoc with helminth Fasciola hepatica in red foxes, not observed in this study.
- Sarcoptic mange has a high mortality rate in San Joaquin kit foxes.
- Without early human intervention, fatality may be as high as 100%.
- In contrast, red foxes appear to have some capacity to recover.
- Transmission to the kit foxes may have been from coyotes in the area or red foxes, dogs, skunks, raccoons, opossums, gray foxes.
A recent study investigated the prevalence of ear mites in wild foxes in Chile.
What is the scientific name of the ear mite?
What fox species did they evaluate?
Why are ear mites a concern in wild populations?
How prevalent were ear mites?
Was one species more affected than another?
Briceño, C., González-Acuña, D., Jiménez, J. E., Bornscheuer, M. L., Funk, S. M., & Knapp, L. A. (2020). Ear mites, otodectes cynotis, on wild foxes (pseudalopex spp.) in chile. Journal of Wildlife Diseases, 56(1), 105-112.
ABSTRACT: We found the ear mite parasite (Otodectes cynotis; Acari: Psoroptidae) in two distant insular endangered fox populations in Chile. We identified O. cynotis in both the Darwin’s fox (Pseudalopex fulvipes) from Chiloe´ and the Fuegian culpeo (Pseudalopex culpaeus lycoides) in Tierra del Fuego. These populations are approximately 2,000 km apart. Infestation rates were high for both endemic foxes: 76% (19/25) of Darwin’s foxes were affected, and 73% (11/15) of Fuegian culpeos had ear mites. Two Darwin’s foxes had abundant ear discharge, and one of these also exhibited secondary infections of Morganella morganii and Geotrichum sp. fungi. Mites were characterized molecularly as Otodectes spp. for the Fuegian culpeo samples. Genetic analyses of two mites found the O. cynotis genotype I, as well as what appeared to be a new allele sequence for O. cynotis. These results confirmed the hypothesis of aworldwide distribution species of ear mite. Introduced chilla foxes (Pseudalopex griseus; n¼11) on Tierra del Fuego Island and domestic dogs (Canis lupus familiaris; n¼379) from both islands were also sampled, but they showed no signs of infection. Our findings provided insight into the genetic diversity, the origins, and the possible impact of this globally distributed mite on endemic free-rangingpopulations of foxes.
- Genus Pseudalopex - endemic to Chile, synonymous with Lycalopex
- Culpeo fox (Pseudalopex culpaeus) - Andean fox, Zorro culpeo
- Fuegian culpeo fox - distinct subspecies on Isla Grande of Tierra del Fuego, vulnerable
- Chilla fox (Pseudalopex griseus) - South American Grey fox, grey Zorro
- Darwin’s fox (Pseudalopex fulviceps) - Zorro Chilote *endangered
- Culpeo fox (Pseudalopex culpaeus) - Andean fox, Zorro culpeo
- Mite infestation resulted in 96% mortality rate for endangered arctic fox cubs in population on Mednyi Island (Vulpes lagopus)
- Goal: survey for Otodectes cynotis in wild foxes, domestic dogs on Chiloe and Tierra del Fuego
- Trapped, squeeze cage for IM ketamine 20 mgkg/xylazine 1 mg/kg or ketamine 2.5 mg/kg/medetomidine 0.05 mg/kg, reversed with yohimbine 0.2 mg/kg or atipamezole 0.25 mg/kg
- Otoscope, cotton swabs in formalin or ethanol for electron microscopy of mites and PCR to speciate mites
- 83% Darwin’s foxes, 79% culpeos, no chilla foxes (TdF) or dogs from Chiloe had ear mites
- Otitis appeared more severe in Darwin’s foxes than culpeos
- Mites from two Fuegian culpeos were O. cynotis genotype 1 on PCR (100% and some 99%) as well as possible new genotypes
- Swab of one Darwin’s fox ear duct had fungus (Geotrichum sp.) and bacilli (Morganella morganii) that was resistant to beta-lactams, doxycycline, and metronidazole
Takeaways:
- One species of ear mite (Otodectes cynotis) with worldwide distribution
- Ear mites and otitis found in Darwin’s foxes and culpeos but not chilla foxes in Chile (Chiloe Island and Tierra del Fuego Island)
- Otitis more severe in Darwin’s than culpeos.
A recent study described gastric dilatation volvulus in maned wolves.
What is the scientific name of the maned wolf?
What are som risk factors for GDV in domestic dogs?
How did these cases present?
What dietary factors may predispose animals to GDV?
Hinton, J. D., Padilla, L. R., Joyner, P. H., Schnellbacher, R., Walsh, T. F., & Aitken-Palmer, C. (2017). Gastric dilatation volvulus in adult maned wolves (chrysocyon brachyurus). Journal of Zoo and Wildlife Medicine, 48(2), 476-483.
Abstract: Gastric dilatation volvulus (GDV) was identified in six adult maned wolves (Chrysocyon brachyurus) housed at the Smithsonian Conservation Biology Institute in Front Royal, Virginia, and the Dickerson Park Zoo in Springfield, Missouri. Four individuals were found dead in their enclosures, and GDV was diagnosed postmortem based on radiographic and necropsy findings. Two individuals were diagnosed with GDV antemortem, with one wolf surviving following surgical intervention and supportive management. A concurrent splenic torsion was identified in three of six cases. Although GDV has been well documented in domestic dogs and is known to occur in maned wolves, objective, detailed case descriptions have been limited in this species. This report represents the first description of a surviving case of GDV in the maned wolf. Thorough species-specific documentation of any acutely fatal condition, such as GDV, is imperative for proper case recognition and medical management, with profound implications for species recovery efforts.
- Risk factors for GDV in domestic dogs – rapid ingestion of food, amount of food ingested, abrupt diet change or dietary indiscretion, exercise behaviors, aerophagia, thoracoabdominal conformation, age, breed, genetics.
- Reported in maned wolves, red wolves, grey wolves.
- Cases 1-3, 6 found dead in enclosure, GDV confirmed post-mortem.
- Case 4 – Decreased energy and appetite, next day vomited foamy fluid, rads showed GDV, OG tube was unsuccessful, ex-lap performed. 180 deg counterclockwise long-axis rotation identified and correctly.
- Case 5 – Found laterally recumbent, GDV diagnosed on rads, went into V tach and died during ex-lap.
- GD +/- V should be considered in any maned wolf presenting with acute abdominal signs.
- Potential role of diet in predisposing animals to GDV.
- Case 2 and 3 were undergoing a diet change.
- Prompted a manufacturer adjustment to increase kibble size to try and reduce risk of GDV in captive NA maned wolves.
- Case 5 and 6 occurred after this change.
- Domestic dogs, it has been suggested that there is an increased risk for GDV with fat or oil as first four ingredients in the diet.
- May result in delayed gastric emptying.
- Domestic dog diets with soy or cereals also considered anecdotally linked to GDV.
A recent study established the vertebral heart scores of the raccoon dog.
What is its scientific name?
How are vertebral heart scores measured?
How did they compare to domestic dogs?
RADIOGRAPHIC MEASUREMENT OF VERTEBRAL HEART SCALE IN KOREAN WILD RACCOON DOGS (NYCTEREUTES PROCYONOIDES KOREENSIS).
Ahn S, Lee M, Shin W, Han Y, Bae S, Choi SY, Kim JT.
Journal of Zoo and Wildlife Medicine. 2022;53(4):817-822.
Raccoon dogs (Nyctereutes procyonoides koreensis), which belong to the Canidae family, are the second most injured wildlife animals rescued by the Gangwon Wildlife Medical Rescue Center. Various imaging evaluation methods including echocardiography have been developed, but thoracic radiography remains essential for the diagnosis and management of heart disease in dogs. In particular, vertebral heart scale (VHS) measurement is usually used to evaluate the dimensions of the heart silhouette on thoracic radiographs and can measure cardiomegaly more objectively. The VHS of 50 raccoon dogs without cardiac diseases were measured using thoracic radiography in right lateral (RL) and ventrodorsal (VD) recumbent positions. The VHS in the RL view of 50 raccoon dogs was 9.03 ± 0.52 vertebrae (v), which was slightly smaller than the VHS measured in the VD view of 46 raccoon dogs (9.79 ± 0.84 v). In addition, the thoracic morphology of raccoon dogs was determined to be intermediate (thoracic depth-to-width ratio, 0.75–1.25), and thoracic morphology, gender, and weight were not significantly correlated with VHS. The VHS of raccoon dogs in this study will help veterinarians diagnose potential cardiac diseases in raccoon dogs.
Background
- Raccoon dog - family Canidae, East Asia, common rehab animal in Korea
- Radiographic vertebral heart score awake under manual restraint
– Long axis and short axis length overlaid on spine starting at T4 vertebral body - sum of number of vertebrae
– Lateral: long axis - carina of mainstem bronchus to apex of heart; short axis - perpendicular at level of caudal vena cava
– VD: long axis - line from base of heart to cardiac apex; short axis - perpendicular line
Key points
- R lat vertebral heart score lower than dogs
- Lateral slightly smaller than VD measurement but significant correlation between views
- Thoracic morphology (deep vs broad): judged as intermediate compared with dogs - likely no correlation between VHS and thoracic morphology
- No correlation of VHS with gender or body weight
- During echos found 4 cases of atrial septal defect and 1 DCM (excluded from VHS study)
Conclusions
- Raccoon dog vertebral heart score reference interval
