1 / 165

Veterinary Medicine: Viral Diseases Overview by Dr. Sherein Saeid

Learn about DNA and RNA viruses, tissue reactions, virus classifications, infections, and viral diseases in cloven-footed animals like FMD and Aphthous Fever. Detailed pathology and preparations explained.

leals
Download Presentation

Veterinary Medicine: Viral Diseases Overview by Dr. Sherein Saeid

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Department of Pathology Faculty of veterinary medicine

  2. ViraldiseasesBYDr. SHEREIN SAEID

  3. VIRAL DISEASES

  4. Introduction

  5. * Viruses can be classified into two classes DNAand RNA viruses.* Most viruses stimulatelymphocytes, however, equine encephalomyelitis stimulateneutrophilsfirstly andthen lymphocytes.* Most viruses result incoagulative necrosis, however, equine encephalomyelitis result inliquifactive necrosis.

  6. Virus and tissue reaction

  7. * Some viruses resulting in lysis and necrosis of cells---- -----------------------------Herpes v.*Some viruses resulting in Proliferation of cells---------- -----------------------------Pox,Leukosis.*Some viruses resulting in Fusion of cells and syncytial formation-------------Paramyxovirus.*Some viruses resulting in Apoptosis of cells-------------- ----------------------------Rift valley fever.*Some viruses resulting in Transformation of cells--------- --------------------------Lung adenomatosis.*Some viruses resulting in Inclusion bodies which either – ----------------intranuclear ( I/N )-----------Herpes. ------------------intracytoplasmic ( I/C )------Pox. ------------------I/N and I/C---------------Paramyxovirus.

  8. Virus and infection

  9. * Acute infection: Virus is eliminated by host immune response. * Chronic or persist infection: Virus is not eliminated and can be isolated for long time.* Latent infection: Virus is apparently eliminated and reappears under stress factors as herpes.

  10. Immunotolerant animal:*Animal get infected by virus and considered it as self antigen(no antibodies)*Animal appeared normal but sheds virus to other animalsAs in BVD infection.

  11. Viral diseases characterized by vesicle formation

  12. Foot and mouth diseaseF.M.DAphthus feverAphthusruminitisDEF.* Viral disease of cloven footed animals; cattle, sheep, camel, and may pig.* Not affect horse.* Ch’ch’ : Vesicle formation on the buccal cavity, interdigital space, rumen, reticulum, omasum, and udder.CausePicornaviridae(epitheliotropic)R.N.AR.O.IIngestion – InhalationPathogenesisVirus ( via R.O.I )………………………………….. Buccal cavity ( str. Spinosum ) …………………………………………Ballooning degeneration(hydropic)…………………………Vesicle( aphthus )or bullae ……………………………………………….Erosion ……………………….. Ulcer…………………………………………..Virus to circulation ………………………………………………………………..Viremia …………………………….G.I.T, Interdigital space & udder.

  13. Lesions (i) MACRO* Buccal lesions : -Vesicle or bullae on anterior 2/3 of the dorsum of tongue. -Dental pad and buccal cavity are also affected.* Foot lesions: -Affect interdigital space ………………………………..Lamness.-In complicated cases the claws may slaughed.* G.I.T lesions: -Vesicles, Necrosis & Erosions in oesophagus, rumenAPHTHUS RUMINITIS., reticulum, omasum,and intestine. -Peticheal H. on abomasums, intestine, and subendocardium.* Udder lesions : Vesicle on Teat extend to Mamaryts …………………………………….Mastitis.(ii) MICRO*Epidermis -Ballooning (hydropic Degenerations) -Vesicle(serous fluid,epithelialcells,inflame.cells(mostly lymphocytes & fewneutrophil………………………………………..Erosion …………………………………………………Ulcer * Dermis Dermatitis i) Congestion ii) Inflammatory cells ( lymphocytes + neutrophils) iii) Perivascular cuffing

  14. Lesions in bucal cavity

  15. Malignant F.M.DDEF.: *Per acute F.M.D of young calves end with rapid death due to(ACUTE GENERAL VENOUS CONGESTION ).*Ch’ch’ non suppurativemyocarditis. Cause :R.N.A virus.R.O.I :Ingestion & Inhalation. Pathogenesis :Virus via R.O.I……Viremia ….Heart muscles & Skeletal muscles.Lesions :(i) MACRO :Greyish necrotic foci on the wall of left ventricle take TIGER appearance SO known as TIGER HEART.(The same lesions are seen in skeletal Ms.)ii)MICRO :Zenker’s necrosis + Inflammatory cells ( Lymphocytes + Macrophages ).(The same lesions are seen in skeletal Ms.)***F.M.D In SHEEP :Vesicle on teat, vulva, & dental pad////// Milder than in cattle//////// F.M.D In Lambs & Pigllets Usually DIE.

  16. Non-suppurative myocarditis

  17. Vesicular stomatitis Vesicular exanthema • DEF.:* • Viral disease affect mainly horses. • * May affect cattle and pig. • * Ch’ch’ vesicle on the buccal cavity, • Interdigital space and udder • * Seasonal disease as it occurs in • summer coz of mosquito. • * Enzootic disease as it occurs in • U.S.A • Cause: • Rhabdoviridae genus (aphthous) e’ 7 Ag types(A,O,C,sat1,sat2,sat3,AsIA1) • e’out cross protection between them • R.O.I • Mosquito bite • wound contamination • Def.: • * Viral disease affect • mainly pigs. • * Ch’ch’ vesicle on the • buccal cavity, • Interdigital space • And udder • Cause: • Calciviridae • R.O.I: • Ingestion

  18. Vesicular stomatitis Vesicular exanthema • Pathogenesis • Virus ( via R.O.I ) ………Buccal cavity ( str. Spinosum)……….. spongiosis………………. Vesicle ( aphthus ) or bullae… Erosion…………Ulcer. • Virus to circulation ……… Viremia …… ……………………………G.I.T, Interdigital space & udder. • Lesions: • As F.M.D  ( Buccal, Foot, and Udder Lesions ONLY) • N.B • (HYDROPIC DEGENERATION REPLACED BY SPONGIOSIS IN HORSE VESICULAR STOMATITIS)

  19. DIAGNOSIS OF FMD,Vesicularstomatitis&Vesicular exanthema:(1) Clinical Signs (Fever(aphthus fever), Off food, Salivation,Smaking of mouth,vesicles on its sites.(2) Post mortem lesions(Macro and Micro).(3) Isolation And IdenificationOf Virus.(4) Diffrential diagnosis from other vesicular diseases.Control measures :(1)Complete eradication of infected animal. (2) Attenuated vaccine for only 1 virus to avoid cross immunity.

  20. PoxViridae virus

  21. GENERAL Characters : • (i) Type : D.N.A virus with 6 genera; Orthopox, Capripox, Lapripox, Suipox, Avipox, and Parapox. • (ii) Tropism : Epitheliotropic. • (iii) R.O.I : Insect bite, Wound contamination (contact ), Inhalation, Ingestion, and • Coitus. • (iv) Animal susceptiple : • * Affect most animals except dogs. • * Horse pox----------- 3 forms; Leg, Buccal, and Genital . Ch’Ch’ Pock lesions . • * Cow & Buffalo …….mild affection. …. Affect teat & udder causing pock lesions. • Microscopic lesions as those of sheep. • * Camel …………Fatal in Young ………… Local in adult. Ch’Ch’ Pock lesions . • * Human … • (i) Pseudo cow pox ( MILKER’S NODULES ) • Transmitted to milkers from teat cow pox through milking. • (ii) Small pox ( VARIOLA ) • Fatal as it has systemic reaction + skin affections. • Human vaccinized against small pox.

  22. (v) Lesions : Cutanous & Systemic lesions. • (vi) Inclusions : I/C inclusion bodies ( GUARNIERI BODIES )  • (viii) Pathogenesis of sheep pox lesions In order : • (i) ROSEOLA St. …….. Red line of dilated vessel. • (ii) MACULA St. …….Edema & Inflammatoty exudates. • (iii) PAPULE St. ………Proliferations of cells. • (iv) VESICULAR St. ……Vesicle formation. • (v) Pastule St. • (vi) UMBLICATED St. ( POCK LESION )…………….. • vesicles ruptured giving ulcer with elevated borders. • (vii) ENCRUSTATION St……..Crust with scab formation. • (viii) HEALING St. …………..Healing of deep pitted ulcer.

  23. Sheep pox - under tail (elevated papule) previous quit

  24. Sheep pox (scab formation) previous quit

More Related