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A Brief Review of Ticks and Tick-Borne Diseases...with a little radiology Billy MacDonald.

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Presentation on theme: "A Brief Review of Ticks and Tick-Borne Diseases...with a little radiology Billy MacDonald."— Presentation transcript:

1 A Brief Review of Ticks and Tick-Borne Diseases...with a little radiology Billy MacDonald

2 Ticks Class Arachnida – closely related to mites

3 Ticks Class Arachnida – closely related to mites obligate blood-feeding ectoparasites – vectors

4 Ticks of Veterinary Importance Ixodidae sclerotized dorsal shield – “hard ticks” Argasidae unsclerotized – “soft ticks”

5 Ticks of Veterinary Importance Ixodidae sclerotized dorsal shield – “hard ticks” sexually dimorphic – females larger – male scutum covers dorsum Argasidae unsclerotized – “soft ticks” little sexual dimorphism

6 Ticks of Veterinary Importance Ixodidae primarily off host – “sit-and-wait” mate on host require days to complete engorgement live outdoors Argasidae live in close proximity to host mate off host require mins - hrs to feed and feed repeatedly live in dwelling/sleeping places of hosts

7 Tick Pathogenesis anemia – heavy infestations

8 Tick Pathogenesis anemia dermatosis – inflammation, swelling, itching, ulceration from tick’s saliva and mouthparts

9 Tick Pathogenesis anemia dermatosis paralysis – neurotoxin present in saliva of some species Dermacentor sp.

10 Tick Pathogenesis anemia dermatosis paralysis vector-borne diseases – viral, bacterial, and protozoal

11 Tick-borne Viral Diseases Colorado tick fever rodents Dermacentor human

12 Tick-borne Viral Diseases Colorado tick fever rodents Dermacentor human tick-borne encephalitis humans, cattle, horses, dogs

13 Tick-borne Viral Diseases Colorado tick fever rodents Dermacentor human tick-borne encephalitis humans, cattle, horses, dogs African swine fever wild suids Ornithodorus pig

14 Tick-borne Rickettsial Diseases Rickettsia rickettsii RMSF rabbits, rodents Dermacentor dogs, humans

15 Tick-borne Rickettsial Diseases Rickettsia rickettsii Anaplasma sp. bovine anaplasmosis: cattle Dermacentor canine anaplasmosis: rodents, ruminants, dogs Ixodes

16 Tick-borne Rickettsial Diseases Rickettsia rickettsii Anaplasma sp. Ehrlichia sp. canine ehrlichiosis dogs, white-tail deer Rhipicephalus

17 Tick-borne Rickettsial Diseases Rickettsia rickettsii Anaplasma sp. Ehrlichia sp. obligate intracellular parasites

18 Tick-borne Rickettsial Diseases Rickettsia rickettsii Anaplasma sp. Ehrlichia sp. Coxiella burnetti...no longer grouped with Rickettsia – Q fever obligate intracellular parasites

19 Borrelia sp. Lyme disease bovine borreliosis avian spirochetosis Tick-borne Bacterial Diseases

20 Borrelia sp. Mycoplasma haemocanis canine hemoplasmosis dogs Rhipicephalus Tick-borne Bacterial Diseases

21 Borrelia sp. Mycoplasma haemocanis Francisella tularensis tularemia rabbits various ticks humans, dogs Tick-borne Bacterial Diseases

22 Hepatozoon canis Rhipicephalus dog Tick-borne Protozoal Diseases

23 Hepatozoon canis Babesia sp. bovine, canine, feline babesiosis, equine piroplasmosis Rhipicephalus Tick-borne Protozoal Diseases

24 Hepatozoon canis Babesia sp. Cytauxzoon felis wild felids Dermacentor cats Tick-borne Protozoal Diseases

25 Lyme Disease...a closer look Ixodes pacificusIxodes scapularis

26 Lyme Disease...a closer look Ixodes sp. white-footed deer mouse etiologic agent: Borrelia burgdorferi humans, dogs, cattle, horses

27 clinical signs...in dogs fever, anorexia, malaise lymphadenomegaly shifting leg lameness – sudden onset painful articular swelling *nonerosive polyarthritis – pathologic changes in the joints are progressive rarely: renal disease (glomerulonephritis), neurological disease

28 diagnosis clinical lab findings – inflammatory changes in synovial fluid serology – ELISA detects antibodies to B. burgdorferi Isolation – culture is most definitive...but also most difficult due to limited number of organisms present – PCR

29 antibiotic therapy – for arthritis: doxycycline, amoxicillin, azithromycin – for neurological manifestations: cefotaxime, chloramphenicol vaccines treatment

30 Hepatozoonosis...a closer look etiologic agent: – Hepatozoon canis...an intracellular parasite in various tissues – transmitted via ingestion of infected tick (Rhipicephalus sanguineous)

31 dog ingests tick

32 sporozoites in GI tractcirculationstriated muscle

33 “onion skin” cyst in skeletal muscle dog ingests tick sporozoites in GI tractcirculationstriated muscle

34 “onion skin” cyst in skeletal muscle ~ 4 weeks...parasite infected neutrophils (gamonts) present in peripheral blood dog ingests tick sporozoites in GI tractcirculationstriated muscle asexual reprod. (merogony) merozoites released into surrounding tissues severe inflamm. reaction neutrophilic granuloma formation

35 Hepatozoonosis...a closer look etiologic agent: – Hepatozoon canis...an intracellular parasite in various tissues – transmitted via ingestion of infected tick (Rhipicephalus sanguineous) clinical signs: – fever, anorexia, weight loss, diarrhea...wax and wane diagnosis: – CBC, Biochem.: non-specific inflammation – UA: +/- proteinuria – muscle biopsy for definitive diagnosis treatment: – symptomatic: NSAIDs

36 Hepatozoonosis via radiology? Periosteal proliferation on the femur, tibia, pelvis and lumbar vertebrae of a dog infected with H. canis

37 Hepatozoonosis via radiology? Periosteal proliferation on the femur, tibia, pelvis and lumbar vertebrae of a dog infected with H. canis...lesions resemble HO

38 Periosteal proliferation on the femur of a dog infected with H. canis Hepatozoonosis via radiology?

39 Hepatozoonosis via Bone Scan Skeletal lesions in a dog infected with H. canis (americanum)

40 References Craig, T.M Hepatozoonosis, pp , In: Infectious Diseases of the Dog and Cat, 2 nd Edition; Craig E. Greene (Ed), W.B. Saunders, Pennsylvania. Greiner, E.C Diagnosis of arthropod parasites, pp , In: Veterinary Clinical Parasitology, 7 th Edition; Anne M. Zajak and Gary A. Conboy (Eds), Blackwell Publishing, Iowa. Holman, P.J., and K.F. Snowden Canine hepatozoonosis and babesiosis, and feline cytauxzoonosis. Vet Clin Small Anim 39: Little, S.E Vector-borne diseases, pp , In: Georgis’ Parasitology for Veterinarians, 9 th Edition; Dwight D. Bowman (Ed), Saunders Publishing, Missouri. Panciera, R.J., Mathew, J.S., Ewing, S.A., Cummings, C.A., Drost, W.T., and A.A. Kocan Skeletal lesions of canine hepatozoonosis caused by Hepatozoon americanum. Vet Pathol 37: Shaw, D. and S. Ihle Joint diseases, pp , In: Small Animal Internal Medicine; Shaw, D. and S. Ihle (Eds), Blackwell Publishing, Iowa.

41 Questions??

42


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