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Squirrel Zoonoses

Squirrel Zoonoses. J. Jill Heatley DVM MS DABVP (Avian), DACZM Associate Professor, Zoological Medicine College of Veterinary Medicine & Biomedical Sciences Texas A&M University, College Station. Tree SquirrelS. Gray... Western - Sciurus griseus Eastern – Sciuris carolinensis

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Squirrel Zoonoses

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  1. Squirrel Zoonoses J. Jill Heatley DVM MS DABVP (Avian), DACZM Associate Professor, Zoological Medicine College of Veterinary Medicine & Biomedical Sciences Texas A&M University, College Station

  2. Tree SquirrelS Gray... Western - Sciurus griseus Eastern – Sciuris carolinensis Arizona ...Sciurus arizonensis Tassel-eared...Sciurus aberti Fox Eastern Fox....Sciurus niger Apache Fox.....Sciurus apache Tamiascirus American Red.....Tamiasciurus hudsonicus Chickaree......Tamiasciurus douglasi Flying Squirrels – Northern Southern and Glaucomys volans

  3. What is a Squirrel ? • Order Rodentia • Family Sciuridae • All continents • Except Antarctica, Australia • 50 genera, 273 species • Subfamily • Cyonomys – Prairie Dogs • Spermophilus – Ground squirrels • Marmota – Marmots • Ammospermophilus – Antelope Squirrels • Tamias – Chipmunks • Tamiasciurus – Chickarees • Sciurus – Tree Squirrels • Glaucomys – New World flying squirrels

  4. Interface • Expanding urban communities • Parks, neighborhoods • Bird feeders • Nature Vacation • Exotic Pets • Research • Rehabilitation • Hunting

  5. Zoonotic Disease • Bacterial • Fungal • Parasitic • Viral • Prion • Literature review

  6. Parasitic zoonoses • Toxoplasmagondii • Intermediate not definitive host • Cryptosporidium parvum • Eastern gray squirrel • Chipmunk • Red squirrel • California Gray squirrel • Hymenolepis nana • Dwarf tapeworm of hamsters • Human enteric disease • Praziquantel • Mange in squirrels is generally notoedric or demodectic and not transmissable to humans

  7. Bacterial Zoonoses • Lyme Disease • Epidemic Typhus • Tularemia • Plague • Leptospirosis • Rat Bite fever • Squirrel Bite fever • Streptobaccillus moniliformis • Spirillum minus • Red legged ground squirrel • Xerus erythropus • Nigeria • Campylobacter spp. • Salmonellosis • Pasteurella multocida • Red squirrel • Yersinia pseudotuberculosis • White tailed antelope squirrel • Citellus lecurus • Yersinia enterocolitica • Grey squirrel Zoonoses Squirrel Disease

  8. Tularemia • Isolated in 1912 • Plague like disease of rodents • Plague foci search • Bacterium tularense • Francisella tularensis • Tulare county of origin, CA • Ground squirrels Spermophilus beecheyii • Zoonoses • Sciurus carolinensis • Infant Bite Arkansas • Prairie Dog (BT Cyonomys ludovicianus) • Titer positive • 3 y with bite • Fox Squirrel • Skinned/dressed Magee JS et al. Tularemia trans by Squirrel Bite. Pediatric Infect Dis J.1989Feb8(2):123-5. Avashia SB at al Emerging Infec Dis 10(3) March 2004 Kirkwood T. Tularemia from the Fox Squirrel JAMA 1931; 96(12);941-942

  9. Leptospirosis • Multiple species • Isolations - serovars • Gray squirrel - ballum • Fox squirrel - grippotyphosa • Zoonosis • Leptospira kirschneri • Southern Flying squirrel • Glaucomys volans • Exported to Japan • 28 29 yo males

  10. Lyme disease • Borrelia burgdorferi sensu latu • Spirochetal bacteria • Most common tick borne disease • Debilitating chronic infection • Tick intermediate • Reservoirs • Western Gray squirrel • Eastern chipmunk • Tamias straitus – eastern & upper midwestern US • Persistent infection, no clinical signs • Ixodes scapularis • European reservoir potential • Gray squirrel Sciurus carolinensis • European tree squirrel – S. vulgaris

  11. Epidemic or Louse Borne Typhus • Bacterium • Rickettsiaprowazekii • Clinical Signs • Fever, Headache, Muscle pain • Rash – trunk spreads to extremities • Doesn’t involve the palms or soles (cf RMSF) • Mort ~ 40% if untreated • Primary Vector • Human Body Louse

  12. Epidemic Typhus • Sporadic cases in Eastern US since 1970s • Most cases in winter when squirrels nest in attics • All non fatal, humans faster recovery with antibiotics • Flying squirrels • Glaucomys volans • Handled, squirrels nests, pets in home • Capable reservoirs • Transient inapparent infection • Squirrel human transmission unknown • Sucking lice (Neohematopinus sciuropteri) • Fleas transmit to squirrels in lab • Direct contact, inhalation of dried squirrel excretions • bites of squirrel ectoparasites • Sucking lice • Flea

  13. Plague • Bacterium - Yersiniapestis • Complex flea rodent cycle • Sylvatic reservoir • Human clinical signs • Severe disease • Fatality rate > 50% if untreated • Rare - Dozen cases / year • Semiarid West • New Mexico • Arizona • Colorado • California

  14. Plague • Periodic plague outbreaks • Flea vector (Flea control!!!) • CS: nonspecific: lethargy, depression, respiratory distress, lymphadenopathy, anorexia • Serologic testing • More susceptible rodent hosts • Prairie dogs • Known reservoir • Ground squirrels • Fox squirrels • Human exposure occurs during outbreaks • Flea bites • Direct contact w nonrodent hosts • Trend of eastward expansion • Epizootic fox squirrels central Texas

  15. Fungal Zoonoses • Dermatophytosis • Sporotrichosis • Sporothrix schenckii • Unknown Sciurid, not captured • Bite 1.5 months earlier in the park • Severe arm lesion responded to 3 months of antibiotic and antifungal therapy Lymphocutaneous Sporotrichosis Associated with a Squirrel Bite: Case Report and Review PS Saravanakumar, P Eslami FA Zar Clinical Infectious Diseases, 23(3)3 Sep 1996) 647-648.

  16. Lesions Etiologies DermatophytosisGray Squirrels • Dermatomycoses, Tinea, “Ringworm” • May accompany parapox fibromas • Systemic Phycomycosis • Circular shape, scaly raised border • Patchy hair loss • Neck , head ,armpits, abdomen • Skin reddening, thin layer serous exudate, crusts, skin nodules • Hair broken off at skin surface, • Fine stubble broken hair Lewis et al. JWD Oct 1975 Urban Gray squirrel mycology

  17. DermatophytosisGray Squirrels • Trichophyton mentagrophytes • Mucor • Candida albicans • Microsporum gypseum, • Scopulaiopsis brevicaulis • Microsporum cookei • Systemic Phycomycosis • Dermatiaceous Fungi – pigmented Phaeoannellomyces wernecklii • Damp weather conditions • Prevalence > 50%

  18. Rule out Alopecia • Sciuruscarolinensis • Glaucomysvolans • Dietary, heritable? • Congenital Alopecia • Dermatophytosis • Louse Bite Lesions • Notoedric Mange • Larval Harvest Mite Lesions • Histology • Fungal organisms in superficial skin, in and around hairs • History, Lesions • Direct examination • Culture • Identify specific fungus • Zoonotic • Young animals more commonly affected • One researcher developed lesions after handling squirrels • Use gloves, wash with soap after handling

  19. Viral Zoonoses • Lymphocytic Choriomeningitis Virus • Gray squirrels serologically positive UK 4/19 • Snowshoe hare virus (SSHV) • Arboviruses • West Nile Virus • Western Equine Encephalitis • Lacross Virus • Eastern Equine Encephalitis • Rabies • Gray squirrel • No human cases associated with squirrel bite • Monkeypox Virus • Encephalomyocarditis virus White et al. Micro Study of Urban Gray squirrel 1975 JAVMA 167

  20. WEE EEE VEE • Alphaviruses, Togaviridae • WEE rare disease in people • Lacrosse Virus, EEE (mort 50%), VEE rare serious disease • Mosquito vector • Hosts (Black tailed jack rabbit, White footed mouse?, ?) • Lacrosse Encephalitis – • Tree squirrels and chipmunks primary amplifying hosts • WEE Viremia – • Gray squirrels (Sciurus carolinensis), California ground squirrels, San Joachin antelope ground squirrels, • Aggressive, bite people, Usu fatal, may survive overwinter • Richardson’s ground squirrels (Spermophilus richardsonii) • contaminated urine, cannibalism • Experimental Infection • Weak, depressed, ataxic, limb paralysis prior to death • Some became hyperexcitable • Brain, brainstem Necrosis & edema • EEE - Gray squirrels • Peripheral inoculation: Encephalitis & death • VEE – Significant viremia, > 50% mort • Mexican ground squirrel - Spermophilus mexicanus • Gray squirrel

  21. SnowShoe Hare Virus • Bunyaviridae • Variant of the La Crosse virus • Encephalitis occasional - NY, Eastern Canada • Antibodies • Experimental infection ground squirrels • Symptomless viremia • Artic ground squirrels • Spermophilus parryii • Golden mantled ground squirrels • Spermophilus lateralis • Yellow-pine chipmunks • Eutamias amoenus • Red squirrels

  22. West Nile Virus • Encephalitis virus • Fox squirrel (Sciurus niger) • Seroconversion late summer early fall • None in urine, fleas • Exp: feces and oral cavity • Experimental infection suggests amplifying host • High seroprevalence • Western gray squirrel (S. griseus) • Eastern gray squirrel (S. carolinensis) • 3/36 live neurologic tree squirrels viremia • similar to WNV-infected birds. • Most squirrels no virus in serum • S. carolinensis • not amplifying hosts • low viremias, lack of mortality • Low seroprevalence 2% • Useful as sentinels • High seroprevalence

  23. Kyansur Forest Disease • Tick borne encephalitis flavivirus complex • 1956 epidemic of people and monkeys • Fever, • hypotension hepatomegaly, hemorrhage/neuro/bronchopneumonia • recovery/late fever • Southern india - 2500 m radius • Striped palm squirrels • Funambulus tristriatus • Antibodies • Viremic infective for Ticks

  24. MonkeyPox Virus • Orthopox virus • Broad primate host range includes humans • Fever rash resembles small pox • Low mortality high morbidity • Infection via direct contact • Main host African tree squirrels • Tree squirrels • Heliosciurus rufobrachium • H. gambianus • Rope Squirrels • Funisciuris anerythrus • F. lemniscatus • Prairie dogs • Poorly competent host • Effective transmitters for veterinary staff

  25. Diseases Infectious • Monkey Pox • Humans 1-10% mortality • Contact, respiratory droplets • CS: fever, cough, conjunctivitis, lymphadenopathy, nodular rash • No treatment • Strict biosecurity, humane euthanasia • CDC website • www.cdc.gov/ncidod/monkeypox • Final rule prohibits • capture, offers to capture, transport, sale, barter, exchange, distribution, or release of a listed animal into the environment. • Prairie dogs (Cynomys sp.) • African Tree squirrels (Heliosciurus sp.), • Rope squirrels (Funisciurus sp.), • Gambian giant pouched rats Cricetomys sp.

  26. EMCV Encephalomyocarditis Virus Genus cardiovirus AKA: Mengovirus Worldwide/Ubiquitous disease of rodents Human: suspected neurologic disease Now thought to be asymptomatic Isolated from feces/intestinal contents Sciurus spp. Red squirrels Wild squirrels (Vizoso et al 1964) Where/ how viral persistence between epidemics unclear Acute death due to cardiac necrosis Important for zoo collection, elephants Chimpanzee, Orangutan Poorly infectious for people

  27. Squirrel brains • Creutzfeldt-Jakob disease (CJD) • “burgoo” • Squirrel brain stew • 5 patients 56-78y • Unrelated, Different towns • Rural Kentucky • Don’t eat brain unless you want be a zombie

  28. Summary • Squirrels are harbor a plethora of zoonoses • Sentinel • Is it the cute factor? • Thanks for your attention

  29. Recommended Readings • Field Manual of Wildlife Diseases in the Southeastern United States, 3rded • Davidson, WR • Zoo & Wild Animal Medicine 5thed • Sainsbury, Rodent Chapter • Infectious Diseases of Wild Mammals • ES Wiliams, IK Barker • Smithsonian Museum of Natural History • North American Mammals • http://www.mnh.si.edu/mna/main.cfm

  30. Clostridium botulinum • Saravanakuma PS Eslami P Zar FA • Lymphocutaneous sporotrichosis associated with a squirrel bite: case report and review. • Clin Infect Dise 1996 sep 23(3) 647-8

  31. Squirrel Fibroma AKA Squirrel Pox Squirrel Pox Virus 1953 Leporipoxvirus Related to Shope’s Fibroma of rabbits Range Range: Maryland, New York, Virginia, Michigan, North Carolina, Ontario Host Gray squirrel Fox Squirrel Red squirrel Significant cause of decline Experimental infections Woodchucks, rabbits

  32. Squirrel Fibroma Lesions Limited to skin Metastasis to the lungs, liver, kidney, and lymph nodes has been reported. Secondary infection Vision obstruction Raised flattened nodules Light colored, little fur 1/16- 1 inch diameter Single or wide dissemination Epizootic Lesions on the eyelid Swelling, discoloration, necrosis of leg or foot Clinical Signs Most infections self limiting, spontaneously regress Debilitation, emaciation, death Rare epizootics Morbidity, mortality many squirrels Florida www.michigan.gov/dnr

  33. Parasite-mediated competition Parapoxvirus: Grey & Red Squirrels Mosquito spread

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