Signalment:  

Adult male coyote (Canis latrans).This animal was found in a storeroom at a racetrack. Police were called because the animal was acting aggressively. The animal was shot twice with a shotgun, and presented for necropsy of suspected “chupacabra.”

Gross Description:  

Over a dozen punctures in the right thoracic wall were associated with five fractured ribs and hemothorax with over seven pleural punctures (euthanasia procedure). An emaciated canid with severe alopecia and thickening of the skin sparing only sparse tan hairs on the dorsal midline and distal extremities was necropsied. Bilaterally, the pinnae had up to 3mm thick tan crusts (hyperkeratosis) with thick, white to tan exudate extending into the ear canals. Milder white to tan flaking and crusts extended along the dorsal midline.

Histopathologic Description:

Ear pinna: Diffusely the epidermis has parakeratotic hyperkeratosis and thick serocellular crusting composed of keratin, eosinophilic karyorrhectic debris, erythrocytes, degenerate and nondegenerate neutrophils, large colonies of bacterial cocci and numerous embedded mites and their eggs. Mites have ~200 x 400um, characterized by jointed appendages, 3um chitinous exoskeleton, dorsal spines, striated muscle, intestinal and reproductive structures and a body cavity. Eggs are oval and thin-shelled, measuring ~30-60um. Diffusely, the epidermis is hyperplastic with prominent rete pegs, festooning, spongiosis, and multifocal areas of ulceration. Within the dermis is an inflammatory infiltrate composed of eosinophils, neutrophils, and plasma cells with fewer macrophages and lymphocytes. Multifocally, superficial and deep dermal vessels are congested and there is lymphangiectasia. Follicles are atrophic.

Morphologic Diagnosis:  

Severe, seroexudative, hyperkeratotic, hyperplastic, and eosinophilic dermatitis with mites and bacteria.

Lab Results:  

Rabies negative; Genetic testing: Coyote (Canis latrans)

Condition:  

Sarcoptes scabiei

Contributor Comment:  

A story from the “south of the border down Mexico way.” The media and locals really wanted this animal not to be a recognized species (see chupacabra website1 ). However, genetic testing identified it as a “plain, oldfashioned” coyote. Sarcoptes scabiei has been reported to have occurred in 10 orders, 27 families, and 104 species.^2,8,9 Mites are highly contagious, but varieties may show high host specificity. Gross findings range from mild scaling and alopecia on the limbs and ventrum to near complete alopecia with hyperpigmentation, lichenification and severe crusting. Histologic changes include pronounced hyperkeratosis with extensive serocellular crusting, pronounced acanthosis, hyperplasia of the stratum spinosum, infiltration of neutrophils, lymphocytes, and plasma cells, and varying degrees of superficial dermatitis, vasodilation, and dermal edema.9 It is surprising how thick macroscopic lesions may be characterized as epidermitis. The inflammatory reaction varies between species and individuals, and in the absence of mite detection, no one change is pathognomonic of sarcoptic mange.

Epizootics of sarcoptic mange caused by Sarcoptes scabiei in coyotes have been reported in Montana, Alberta, Wisconsin, Pennsylvania, New York, Kansas, Texas, Louisiana and South Dakota. Reports of mangy coyotes in south Texas go back to the 1920’s. Adult males and particularly transient coyotes are significantly more likely to be infected. Severely affected animals have significantly less body fat. Infected individuals may be listless, show less fear of humans and are significantly more likely to seek shelter or food near human settlements. Mortality rates are higher in infected individuals; however, in southern climates, mange has not been shown to directly cause death.^2,8,9

The myth of “El Chupacabra” appears to have arisen in Puerto Rico in the early 1990’s and spread from there to South America, Mexico and the southern United States. Originally described as being ~3 feet tall with dorsal spines, leathery skin, a kangaroo-like posture, fangs and a forked tongue, the legend has morphed to include creatures resembling leathery dogs with pronounced spinal ridges and eye sockets. Be it the work of vampires, sadists, Santaría cultists or drug lords, chupacabra has provided a mythical explanation for unusual deaths of animals and humans.

The altered appearance and increased human contact of affected coyotes (the only animals identified as chupacabras and examined thus far in a scientific fashion) with sarcoptic mange provides a diagnosis, albeit banal, for the “chupacabra” phenomenon. Deflating the myth, it is hard to tell your kids that, “a mangy coyote will come after you if you don’t do your homework or eat your supper.”

JPC Diagnosis:  

1. Haired skin, pinna: Epidermal hyperplasia and hyperkeratosis, diffuse, severe, with mild eosinophilic dermatitis and numerous intracorneal mites, coyote, Canis latrans.

2. Lymph node, paracortex: Plasmacytosis, marked.

Conference Comment:  

The contributor provides a concise and insightful summary of the epidemiology, gross, and histologic lesions associated with Sarcoptes scabiei in a coyote. In this section of pinna, the mites are numerous and have a thin cuticle which is thickened by striated muscular attachments. The most striking and diagnostic features are the numerous cuticular spines present on the chitinous exoskeleton of the adult female mites in this section. Male mites are approximately twothirds the size of the females and do not have prominent cuticular spines.^2,4,6 S. scabiei mites are relatively host specific and different varieties are morphologically indistinguishable^.2,6 The mite is common in humans, pigs, dogs, and goats and uncommon to rare in cattle, sheep, horses, and cats. It is the most important ectoparasite in swine causing maculopapular eruptions on the rump, flank, and abdomen of young growing pigs (hypersensitivity form) and thick crusts on the pinnae, head, neck, and legs of older multiparous sows (hyperkeratotic chronic form).⁶

Recently, there has been a suspected increase in host range of this ectoparasite with subsequent global diversification.^3,7 As a result, S. scabiei has been introduced to novel species, likely due to increased human interaction.⁷ Most severely affected are the wild canids such as coyotes, red foxes, and grey wolves in North America; the southern hairy-nosed wombat in Australia; and the chamois, red deer, roe deer, and ibex in Europe. The introduction of this pathogen into new locations and hosts has been shown to produce high morbidity and mortality in these species.^3,6,7

The pathogenesis involves direct damage due to the burrowing mite, irritation from mite excretions, and hypersensitivity to mite antigens in the cuticle, saliva, and feces. This leads to both an immediate (type I) and delayed (type IV) hypersensitivity reaction causing an intense pruritus and alopecia.2,4,5,6 Pruritus causes decreased food intake (or ability to catch prey), dehydration, and severe weight loss along with secondary bacterial or fungal dermatitis. Eventually, animals succumb to the emaciation and dehydration if not properly treated. Poorly nourished or immunosuppressed animals develop massive mite burdens known as “Norwegian type scabies.”^4,5,6

Conference participants noted several examples of female mites burrowing into and under the stratum corneum forming “molting pockets” in the skin where the female will mate and lay eggs.⁴ Interestingly, many had difficulty finding eggs within their sections despite the presence of numerous molting pockets. Conference participants also discussed other types of burrowing mites that affect veterinary species such as Notoedres sp. and Knemidocoptes sp.⁶ Additionally, participants noted mild reactive lymphoid hyperplasia with paracortical plasmacytosis in the adjacent lymph node. This reaction is relatively mild and likely related to chronic inflammation.

References:

1. http://www.monstropedia.org/index. php?title=Chupacabra.

2. Bornstein S, Morner T, Samuel WM. Sarcoptes scabiei and sarcoptic mange. In: Samuel WM, Pybus MJ, Kocan AA eds. Parasitic Disease of Wild Mammals. 2nd ed, Ames, IA: Iowa State University Press; 2001:107-119.

3. Fraser T, Charleston M, Martin A, et al. The emergence of sarcoptic mange in Australian wildlife: An unresolved debate. Parasit Vectors. 2016; 9:316.

4. Gross TL, Ihrke PJ, Walder EJ, Affolter VK. Skin Diseases of the Dog and Cat Clinical and Histopathologic Diagnosis. 2nd ed. Ames, IA: Blackwell Publishing Professional; 2005:216-219.

5. Hargis AM, Ginn PE. Integument. In: McGavin MD, ed. Pathologic Basis of Veterinary Disease. 5th ed. St. Louis, MO:Elsevier; 2012:1042- 1045.

6. Mauldin E, Peters-Kennedy J. Integumentary system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. Philadelphia, PA:Elsevier; 2016:673-680.

7. Murray M, Edwards M, Abercrombie B, St. Clair C. Poor health is associated with use of anthropogenic resources in an urban carnivore. Proc Biol Sci. 2015; 282(1806):20150009.

8. Pence DB, Ueckerman E. Sarcoptic mange in wildlife. Rev Sci Tech. 2002; 21:385-398.

9. Pence DB, Windberg LA, Pence BC, Sprowls R. The epizootiology and pathology of sarcoptic mange in coyotes, Canis latran, from South Texas. J Parasitol. 1983; 69:1100- 15.

10. Pence DB, Windberg LA: Impact of a sarcoptic mange epizootic on a coyote population. J Wildlife Mgmt. 1994; 58:624-633.