W7 Herpesvirales + Parvovirdae PDF - Lecture Notes

W6 Lecture series 1- Order: Herpesvirales 2- Family: Parvoviridae Herpes: Greek word: herpein : (“To Creep") 1  Learning objectives To be familiar with the general criteria of the Order Herpesvirales and t...

W6 Lecture series 1- Order: Herpesvirales 2- Family: Parvoviridae Herpes: Greek word: herpein : (“To Creep") 1  Learning objectives To be familiar with the general criteria of the Order Herpesvirales and the family and Parvoviridae To study the replication cycles of the Herpesviruses and Parvoviruses To study the pathogenesis of Herpesviruses and Parvoviruses infection To know the most common viral diseases caused by Herpesviruses and Parvoviruses Laboratory diagnosis of various diseases caused by the members of Herpesviruses and Parvoviruses To be familiar with the various Prevention/Control/Vaccine strategies 2  Herpesvirales -new classification Order: Herpesvirales accommodates 3 Families 3 Subfamilies 17 Genera 90 Species Morphology and structure of Herpesviruses 4  General properties of of Herpesvirus ◼ Structure and Composition ❑ Enveloped, Spherical icosahedron, 150-200 nm ❑ Double-stranded DNA, linear ❑ More than 35 proteins ❑ Replication from nucleus (budding) ❑ Important features ◼ Encode many enzymes ◼ Establish latent infections ◼ Lifelong persistence ◼ A significant cause of death in immunocompromised hosts ◼ Some can cause cancers 5  Morphology and structure of Herpesvirus 6  Herpesvirus genome structure and organization ◼ Genome: monopartite, linear, dsDNA genome of 120-240 kb ◼ The genome contains terminal and internal repeated sequences ◼ Genome contains unique long (UL) and unique short (US) regions bounded by inverted repeats (ITR) allow rearrangement of unique regions 7  Replicative cycle of Herpesviruses Herpesvirus transcription, translation, and DNA replication. Transcription and posttranscriptional processing occur in the nucleus Translation in the cytoplasm Some of the  and  proteins are involved in further transcription Some  proteins in DNA replication.  Replicative cycle of Herpesviruses vhs gC viral DNA gD IE genes tif E genes gB DNA replication L genes cell-cell Inclusion bodies spread  Biological properties of Herpesviruses ◼ DNA synthesis and viral assembly occur in the nucleus (IN) ◼ Production of progeny virus resulted in host cell distortion ◼ Persistent infection with periodic or continuous shedding ◼ Herpesvirus can remain latent in the host cell -Alpha: Neurons -Beta: Monocytes -Gamma: Lymphocytes ◼ Beta & Gammaherpesvirinae infections often clinically silent in mammals ◼ Most Herpesviruses establish a systemic infection, a cell-associated viremia being detectable during primary infection 10  Herpesvirus-Replication cycle cont… Formation of capsid Infected cells with “Owl eye” Herpesvirus Budding through a intranuclear inclusion intranuclear inclusion nuclear envelope bodies ◼ Latent replication : replication of circular viral episome in tandem with the host cell DNA using the host cell replication machinery 11  Why Herpesviruses are difficult to be controlled? 1- Infect crucial target tissues: brain and maternal placenta 2- Latent (as circular DNA in the nuclei of ganglia of lymphocytes) of recovered animals, subsequent reactivation during stress causes disease or tumours 3- All are cell-associated and can spread between cells by cell fusion Fate/outcomes of Herpesvirus infected cells ◼ Lytic Herpesviruses: destruction of the infected cells due to alteration in the biochemical and biological process in the cell ◼ Non-lytic Herpesviruses: integrated in the host cell genome resulted in changes in the cells -Distortion or change in the cell nucleus -Change in the appearance of cell membrane - Appearance of viral protein (gD) in the cell membrane 12  Some Selected Herpesvirus diseases Human Equine Bovine Caprine Avian Feline Canine Swine -EHV-1 -IBRV -MDV -EHV-2 -BHV-2 -ILTV -EHV-3 -DVE -EHV-4 -EHV-5 -EHV-9 Fish Salmonid Herpesvirus 1, 2, 3 13  Herpes simplex virus (HSV) Clinical Manifestations ◼ HSV is involved in a variety of clinical manifestations which includes 1. Acute gingivostomatitis 2. Herpes Labialis (cold sore) 3. Ocular Herpes 4. Herpes Genitalis 5. Other forms of cutaneous herpes 7. Meningitis 8. Encephalitis 9. Neonatal herpes 10. Keratoconjunctivitis (corneal ulcers)  Diagnosis of HSV Stained smear of materials from Herpesvirus simple lesion Positive IFAT for HSV Multinucleated giant cell and CPE of HSV in cell antigen in epithelial cell. intramuscular inclusion bodies culture Note ballooning of cells. Pink areas within the epithelial cell nuclei are intranuclear IB.  EHVs revised classification- ICTV most-up-to-date Alphaherpesvirinae -EHV-1 -EHV-4 Gammaherpesvirinae -EHV-2 -EHV-5 16  Equine Herpesviruses EHV- Clinical EHV-1 Equine Abortion Virus Respiratory, abortions, encephalomyelitis Can cause four manifestations of disease in horses, including neurological form, respiratory disease, abortion and neonatal death. EHV-2 Granulomatous dermatitis EHV-3 Genital lesions (Equine Coital Exanthema Virus) Causes a venereal disease called coital exanthema that affects the external genitalia but has not been shown to affect fertility. EHV-4 Equine Rhino pneumonitis syndrome Causes a nonfatal upper respiratory tract disease in foals and is uncommonly associated with abortion and rarely with neurological disease EHV-5 Equine multinodular pulmonary fibrosis (EMNPF) EHV-8 Rhinitis EHV-9 Asymptomatic in equids, severe disease in other species  Clinical sings of the EHV ◼ Fever commonly precedes the other clinical signs ◼ Respiratory disease: fever, coughing, and nasal discharge ◼ Abortions typically occur late in pregnancy (greater than eight months, although earlier cases are reported) ◼ Neurological disease associated with EHV-1 can range from mild incoordination to severe posterior paralysis Severely affected horses may become recumbent and unable to rise-Incoordination -Lower leg swelling -Weakness in hind limbs ◼ Inability to pass urine or manure Neurological problems (not by direct neuronal infection but indirectly via endothelial infection) – ◼ Vasculitis→ thrombosis → resulting in an ischemic condition in the spinal cord → neuronal anoxia → neuronal necrosis 18  Pathogenesis of -(EHV1/4) ◼ Transmission: direct or indirect contact with infectious nasal secretions, aborted fetuses, placentas, or placental fluids ◼ Horses may become latent carriers of EHV; virus may be reactivated after stress ◼ The usual mode of transmission is venereal ◼ The pathogenic mechanisms of EHV-1 and EHV-4 differ significantly ◼ EHV-1: have a predilection for vascular endothelium, especially the nasal mucosa, lungs, adrenal, thyroid, and CNS ◼ EHV-1: gains access to peripheral tissues via cell-associated viremia, which may manifest as abortion or neurologic disease ◼ EHV-4 infection is restricted to respiratory tract epithelium and associated lymph nodes ◼ 19  General pathogenesis of EHV1&4 Peripheral blood mononuclear cell (PBMC) 20  Pathogenesis: Mechanism of EHV-1 induced abortion abortions Bronchioles Cell- associated T lymphocytes viremia CD4+ *CD8+ Endometrial vessel EHV infects Thrombotic endothelial occlusion cells and leukocytes vasculitis IL2 induces Virus infects fetus Adhesion molecules Inflammation Vasculitis  Mechanism of EHV-1 induced abortion cont….. Viraemia Endometrial endothelial cell infection Endometrial vasculitis and thrombosis Extensive infarction: virus negative fetus  Complications of EHV-1 infections l PREGNANT MARES l -Asymptomatic l -Abortion 4-5 months later l -Last trimester (7-11 months) l -Fresh looking aborted fetus l FULL TERM FOALS l -General weakness l -Pneumonia l -Death Infected fetuses aborted in late pregnancy are often fresh- death due to suffocation following rapid placental separation. Interstitial pneumonia in aborted foal ** EHV-4 may rarely cause isolated abortions but not abortion storms  Equine Rhinopneumonitis A disease of young horses (up to 2 years), and Infection in Older animals – mild clinical signs Mixed syndrome caused by 4 Herpesviruses (EHV-1 (subtype-1, subtype-2), EHV-2, EHV-3, EHV-4) EHV-4 replication is mainly restricted to URT EHV-1 infection extends beyond the respiratory tract (Cell associated viremia). Equine Herpesvirus 2-associated Granulomatous dermatitis Multifocal to coalescing areas of necrosis marked by histiocytic cell infiltration and the presence of giant cells. Intranuclear and intracytoplasmic viral particles consistent with Herpesvirus 25  Equine Herpesvirus-3 (EHV-3)(Equine Coital Exanthema) ◼ Acute STD (papules, vesicles, pustules, and ulcers) penis and prepuce of stallions -external genitalia and peripheral skin of mares - lips, external nares, nasal mucosa, and conjunctiva: ◼ Lesions heal after 14 days l, leaving depigmented patches on the vulva -erosions and ulcers on prepuce and penis of the male - White depigmented spots on vulva, penis, prepuce develop and stay for life – helps in identifying previously infected animals or carriers EHV3 exhibits no cross-reactivity with other Herpesviruses High antibody incidence >50% Experimental inoculation in the uterus – abortion occurs Subclinical respiratory infection in yearling horses 26  Diagnosis and Control-(EHVs) ◼ Case history ◼ Clinical signs ◼ Virus isolation from aborted fetus using cell culture ◼ PCR ◼ Serology: -Serum Neutralization test (SNT) -Complement fixation test (CFT) ◼ Haematology: Leukopenia ◼ Vaccination -Early age - periodically depending on management factors - recommended to reduce the incidence and severity of disease ◼ 27  EHV-1 Vaccines No vaccine provides complete, permanent protection 28 Herpes viruses of pigs 29  Pseudorabies Virus (PRV)-(Aujeszky’s Disease, Mad Itch) Alphaherpesvirus (Porcine herpesvirus-1) ◼ Genus: Varicellovirus, Single serotype ◼ Disease of pigs (natural host) that is fatal for most other animals ◼ Dead end hosts (dogs, cats, and cattle) ◼ Morbidity ❑ Up to 100% in piglets, mild or no signs in adults -Aujeszky first identifies ❑ Up to 20% of abortions ADV in cattle and dogs -Determines swine are ◼ Mortality natural hosts ❑ Highest in younger animals ❑ Decreases with age ❑ Always fatal in other species  Modes of transmission of Pseudorabies Virus (PRV) ◼ Most common Pigs ❑ Respiratory ❑ Oral ❑ Nose-to-nose contact ◼ Aerosol ◼ Fomites ❑ Contaminated bedding and water ❑ Meat products or carcasses ◼ Latent carriers possible ◼ Contact with infected pigs ◼ Ingestion of contaminated raw meat ◼ Rarely lateral transmission ◼ Pig bite—uncommon  Clinical Signs: Pigs ◼ Incubation period: 2 to 6 days ◼ < 1 week old piglets ❑ Fever, listlessness, anorexia ❑ Neurological signs ◼ Tremors, paddling, seizures, dog-sitting ❑ High mortality within 24 to 36 hours ◼ Older piglets/weaned pigs ❑ Similar signs ◼ Respiratory, neurological, vomiting ◼ Lower mortality Adult pigs − Mild or subclinical infection − Respiratory and neurological signs − Pregnant sows: reproductive signs Pathogenesis of Pseudorabies (PRV)  Clinical Signs of PRV: Other Species ◼ Cattle and sheep ❑ Intense pruritus: Mad Itch ◼ Licking, rubbing, gnawing, self-mutilation ❑ Neurological signs ◼ Dogs and cats ❑ Similar to cattle and sheep ❑ Resembles rabies ❑ Sudden death ◼ Death in 1 to 2 days  Some Necropsy and histology findings of Pseudorabies Virus (PRV) Liver necrosis Neutrophils infiltration Necrosis in tonsils Pigs -Neurological Nonsuppurative meningoencephalitis -Respiratory Necrotic tonsillitis, bronchitis, bronchiolitis, alveolitis -Focal necrosis Center for Food Security and Other species Public Health, Iowa State -Spinal cord lesions University 35 Laboratory diagnosis of PRV 36  Vaccines against PRV in swine species Inactivated vaccines Modified live virus vaccine Deletion mutant vaccines Sub-unit vaccine plus some immune stimulating complex called (ISCOMs) Vaccination prevents/minimize diseases but not the infection 37  Control of the PRV ◼ IMMEDIATELY Notify authorities ◼ Federal ❑ Area Veterinarian in Charge (AVIC) www.aphis.usda.gov/animal_health/area_offices/ ◼ State ❑ State Animal Health Officials www.usaha.org/Portals/6/StateAnimalHealthOfficials.pdf ◼ Quarantine Isolation and testing of new animals ◼ Test and slaughter approach: UK eradication ◼ Biosecurity measures ❑ Prevent entry ❑ Double fencing ◼ Disinfection ❑ Phenols, quaternary ammonium compounds ❑ Inactivated by heat, sunlight  Porcine Herpesvirus-2 Inclusion body Rhinitis-Atrophic rhinitis in pigs Cytomegalic inclusion disease Caused by Suid betaherpesvirus 2 (SuHV-2) Normally only seen in either piglets less than 3 Normal weeks old or pregnant sows AR 39  Bovine Herpesviruses Bovine Herpesviruses Clinical pictures BHV-1.1 Implicated in respiratory diseases; may cause abortion BHV-1.2a Implicated in infectious Balanoposthitis /infectious pustular Vulvovaginitis syndrome and may cause abortion BHV-1.2b Implicated in infectious Balanoposthitis/infectious pustular Vulvovaginitis syndrome and has not been associated with abortion BHV-2 Bovine Ulcerative Mammillitis (Bovine Herpesvirus II) (Allerton virus) ◼ Has only one antigenic type but three genotypes based on enzyme digestion pattern ◼ Subtype 1 = respiratory ◼ Subtype 2 = genital: 1.2a and 1.2b isolates ◼ Subtype 5 (former 1.3) =encephalitic form  Bovine Herpesvirus-1-IBRV ◼ It may present as ocular, genital , respiratory and neurologic diseases ◼ Respiratory disease :(Infectious Bovine Rhinotracheitis, IBRV) lead to sever fatal bronchopneumonia ◼ Genitalia resulting in - Abortion and Vulvovaginitis (infectious pustular Vulvovaginitis, (IPVV)) -Infectious Balanoposthitis (infection of the penis, (IBPV)) ◼ Meningoencephalitis in young calves infrequently occurs with BHV-1 ◼ Pathogenesis: -Virus replicates in the upper respiratory tract -Spread via lacrimal ducts -Virus can be recovered from nasal secretion for almost 2 weeks PI - Genital infections are most likely venereal transmission 41  IBRV-Infection in the animal replication in Infection of Reactivation epithelial cells susceptible animal from latency replication in establishment of epithelial cells latency (rhinotracheitis) (infection for the first time) systemic cell-associated spread encephalitis infection of the fetus -> abortion  BHV-1 Pathogenesis - primary lesions Vesicle/Pustule Eroded lesion virus, infected cells debris epidermis dermis Fever, dyspnea, cough T lymphocytes Cell associated viremia Neutrophils Monocytes BHV-1 Induces pro-inflammatory cytokines BHV-1 Down regulates MHC-I BHV-1 Causes apoptosis of CD4 lymphocytes BHV-1 Causes transient immunosuppression  Clinical signs and lesion of IBRV infection in cattle Mucopurulent to fibrino-purulent rhinitis and fibrinous tracheitis Red tinged serous fluids Vesicle (raised pale area) BHV-1.1 induced from eroded vesicles – and/or eroded vesicles within conjunctivitis (IBR) Red Nose the nostril of a cow with IBR Characteristic IBRV IBRV trachea mucosal lesions are typified by adherent, whitish, necrotic material Infectious pustular Vesicles on the raised above the mucosal vulvovaginitis penis surface (IPV) 44  Clinical signs and lesion of IBRV infection in cattle cont…. Vesicles in the High mortality Focal necrosis in liver, lung, esophagus of neonatal calf with generalized kidney, heart etc. IBRV infection most abortions that recognized occur in the last 4months of gestation, earlier abortions generally not detected Neurological signs – Neurological signs, incoordination Opisthotonus 45  Clinical signs and lesion of IBRV infection in cattle Neuronal necrosis, shrinking and Mononuclear Softening (malacia) eosinophilia of perivascular cuffing of the cortex Perikaria and nuclear Piknosis (red neuron) 46  IBRV-Diagnosis and Control ◼ Case history, clinical signs, PM lesions ◼ Proper sampling (Feces, fecal swabs, nasal swabs) ◼ Detection of the viral particles by EM ◼ Viral isolation from conjunctival swabs and placenta ◼ IFA, IP Nasal discharges ◼ PCR : for the conformation of diagnosis ◼ Serology: virus neutralization: ELISA ◼ Vaccine is available in the form of injection and intranasal ◼ Modified-live (attenuated) ❑ IN= intranasal ❑ IM= Intramuscular ◼ Inactivated ❑ IM= Intramuscular 47  IBRV- Vaccines ◼ I-Modified Live Vaccine ◼ One is intended for parental use and is of bovine fetal kidney tissue culture ◼ One is an IN vaccine and of rabbit tissue culture origin ◼ The 3rd one contains ts mutant of BHV-1 and is also intranasal and is of bovine tissue culture ◼ MLV strains are differentiated from the field strains by digestion with restriction endonucleases. ◼ They induce a rapid immune response, long lasting immunity, and result in local and mucosal immunity ◼ II-Inactivated Vaccine Do not cause immunosuppression, abortion, or latency But also, do not prevent the development latency following exposure to field strains Are safe in pregnant cows, stable in storage, and do not cause shedding of virus  III-Subunit Vaccines: Vaccines for eradication of IBRV/DIVA gB ELISA for antibodies gB gD gD infected gB vaccinated gB gene for gE gE gB deleted infected gD subunits vaccinated gE gD IBRV vaccines do not contain gE viral protein TK negative gC deletion mutant and therefore allow serological Induces both humoral and CM immune responses differentiation. Cattle-type BHV1 gE Ab Safe in pregnant cows specifically detects antibodies to gE and does Efficacious in the presence of maternal antibody not react with antibodies from gE-deleted vaccines.  Bovine Herpesvirus-2 (BHV-2) (Pseudolumpy skin disease) Bovine Viral Mammillitis, Allerton virus ◼ Isolated from cattle with generalized skin disease Mammilitis and stomatitis ◼ Virus may be transmitted by biting flies ◼ Diagnosis: based on Facial skin lesions -Clinical sings A: Mild alopecia with crust above the left eye and one of he left ear B: Severe alopecia of the dorsum -Viral isolation in tissue culture of ear bilaterally -Serology in paired samples will demonstrate an increase in Abs 50  Malignant Catarrhal Fever Virus (MCFV) MCF : clinically dramatic and often lethal infection of many species of Bovidae and Cervidae caused by a member of the MCF virus (MCFV) group Genus Macavirus /subfamily Gammaherpesvirinae MCF: Fatal lymphoproliferative disease of cattle and sheep characterized by lymphadenopathy Snotsiekte Widespread tissue accumulation of lymphocytes Very high mortality rate (>95%) Button Acute, high fever, catarrhal inflammation, corneal ulcers edema, enlarged nodes, skin lesions, +/- diarrhea Exist in nature as in apparent infections in well adapted hosts Severe inflammatory lesions of the muzzle, eye, respiratory and digestive tract with swollen lymph nodes and terminal encephalitis Peripheral (centripetal) corneal opacity is an 51 important clinical sign suggestive of MCF in cattle. Urinary tract Tongue bladder Notifiable diseases to the OIE MCF Virus Transmission between Carrier and Clinically Susceptible Hosts 99 CpHV-2 67 Ibex-MCFV OvHV-2 68 Aoudad-MCFV 78 Muskox-MCFV 54 MCFV-WTD OvHV-2 100 Oryx-MCFV Clinically Susceptible Hosts 89 HiHV-1 87 OvHV-2 AlHV-1 AlHV-2 Subclinical MCF Death Infection Recovery Carriers OvHV-2 X  Herd #3 234Hd 0.4% A sheep-associated MCF N 1 outbreak in a Colorado ranch Herd #2 2933Hd (2002) 2 6.1% 4 MO: Oct Nov Dec Jan Feb Mar Apr May 5 # MCF 0 0 2 4 9 8 12 6 6 # MCF 0 0 0 12 6 -- # MCF 0 0 0 0 1 -- Totals 2 4 9 20 19 54 out of 761 died (7.1%) Herd #1 234 Hd Sheep Feedlot 18.4% ~Nov 1 1 mile Li, et al., 2008, CVJ  Caprine Herpesvirus-1 and 2 (CpHV) CpHV-1 in goats ◼ Isolated from young goats (1 week) dying in North America with enteric sings and necrosis and ulceration in the rumen, cecum, and colon ◼ It may cause abortion, Vulvovaginitis, Balanoposthitis ◼ It may cross react with BVH-1 serologically: they may have common ancestors ◼ Infection in adults, usually in-apparent, and genital disease may occur as Vulvitis CpHV-2 in captive Sika deer a- nasal discharges b- oral vesicles on the muzzle and tongue c- growth lesions on the kidney d- growth lesions on the lung 54 Herpes viruses of Carnivores 55  Canine Herpesvirus-1 Canid Herpesvirus-1 ◼ Neonatal deaths, abortion and mummification as well as fatal systemic infection in newborn pups ◼ Induce genital lesions in male and female dogs ◼ Affected animals appear healthy but often present a history of infertility ◼ Could be a part of the canine respiratory disease complex (Kennel cough syndrome) ◼ No vaccine is available ◼ Removal or separation of infected animals should be considered Hemorrhagic infarcts of the kidneys 56  Feline Herpesvirus-1 (Feline Viral Rhinotracheitis) ◼ Cause feline viral rhinotracheitis (FVR) along with the upper respiratory disease ◼ The hunched-up appearance of a cat with its head on the floor. The third eyelid is prominent. ◼ Associated with conjunctivitis, ulcerative keratitis, ulcerative stomatitis, abortions, and pneumonia ◼ Spreads by direct Cat-to-Cat contact through infectious discharges and aerosolized microdroplets ◼ Protective immunity is relatively short ◼ Vaccination every 6-12 months is recommended 57  FeHV-1:Transmission, Pathogenesis and Clinical Signs Virus is shed in discharges from the nose, eyes, throat Transmitted through direct/indirect contact ◼ Conjunctivitis and conjunctival edema ◼ Possible dyspnea (open mouth breathing) as a Dendritic ulcers result of blockage of nasal passages ◼ Keratitis ◼ Dendritic ulcers in the cornea with possible perforation Stromal keratitis Vascularization and hazy infiltrate at the leading edge of the vascularization Intestinal loop flaccid and hemorrhage  Anti-herpesvirus chemotherapy in cats Systemic antiviral therapy: This uses a human anti-herpes antiviral drug, also known as Famciclovir, that has been proven to be safe in cats. It is given by mouth and helps manage severe infections. Topical ocular antiviral therapy: These anti-herpes drugs, known as Idoxuridine, Trifluridine, and cidofovir, can be used as eye drops in treating cat herpes. Eye drops are usually given daily and sometimes combined with other treatment options. Points to consider for the anti-Herpes chemotherapy in cats Due to its high bioavailability after oral administration, acyclovir is more recommended for oral use than in ophthalmic ointments. Idoxuridine and Trifluoridine are recommended only for topical use in cats due to their high toxicity when used systemically. Penciclovir, used in ophthalmic ointment, has proved to be the most potent antiviral drug against ocular Herpesvirus disease in cats. 59 Herpesviruses of Birds 60  Infectious laryngotracheitis Virus –ILTV Gallid alphaherpesvirus-1 (GaHV-1) Dyspnea in pullets ◼ ILT is acute, highly contagious disease of chicken ◼ Severe dyspnea, coughing and rales ◼ Worldwide, USA – 1926 ◼ Hosts – chickens and pheasants ◼ Etiologic agent – Gallid herpesvirus 1, one serotype although strains of virus differ significantly in virulence ◼ Transmission – introduced into a flock by carrier birds ◼ Mostly via inhalation – occasionally via ingestion ◼ Pathogenesis – severe laryngotracheitis characterized by necrosis, hemorrhage, ulceration and the formation of diphtheritic membranes ◼ Diphtheritic membrane – may form a tube the length of trachea – occluding air flow ◼ “Pump handle respiration” ◼ Death occurs from asphyxiation 61  Clinical features of the ILTV L- normal) (C- hyperemic) (R - fibrin) ◼ Clinical features – 2-8 days ◼ Most common – chickens 4-18 months ◼ Marked respiratory disease – extension and slinging of the neck during inspiration ◼ Head pressing, resting on breast during exhalation, coughing, rattling ◼ Birds may cough up bloody mucus that stains walls and posts (expectoration of mucous-tinged blood) ◼ Morbidity – 100%, mortality 20-70% - depending on virulence of the strain 62  Diagnosis and control of ILTV History, Clinical Signs, PM lesions Proper sampling FAT staining of smears and tissues Virus isolation – nasal mucosa -CAM of ECE stunted embryos which die 2-12 days PI -GHV-1 grows well in various cultures Intranuclear inclusion bodies Serology – detection of neutralizing antibody using pock or plaque reduction assays PCR Vaccines -Live attenuated ILTV vaccines (cell culture or ECE origin) -Viral vector recombinant vaccines Administration of vaccines; eye drops, spray, or through drinking water 63 Gallid Herpesvirus-2 (GaHV-2): Marek`s Disease Virus-MDV ◼ Lymphoproliferative & neuropathic diseases of chickens ◼ A highly contagious viral infection mainly affects chickens ◼ It can also affect Pheasants, Quails, and Turkeys ◼ Three serotypes of the virus ◼ Serotype 1: pathogenic and oncogenic strains Strains of serotype 1 divided into -Mildly virulent -Virulent -Very virulent ◼ Serotype 2: avirulent and non-oncogenic strains ◼ Serotype 3 (HVT): avirulent, in turkey only (vaccine strains) ◼ Clinical signs from 6 – 16 weeks ◼ Majority of neoplastic changes in broilers ◼ Mononuclear (lymphoblasts) infiltration in peripheral nerves and other organs 64  Pathogenesis of Marek´s disease virus ◼ Classical MD: Neurolymphomatosis: loss of coordination, asymmetric paresis and paralysis ◼ Acute MD – expansive burst in the flock, depression, ataxy, paralysis in some animals. Significant mortality without neurologicchanges ◼ Lymphomatosis of the eye – lymphoblastoid infiltration of pupil, blindness ◼ Skin form – round, nodular lesions in feather follicles  Transmission of MDV ◼ Transmission: highly contagious, concentrates in Feather Follicles and spreads by bird-to-bird contact, by contact with infected dust and dander ◼ MDV particles can survive for months in chicken-house dust and litter ◼ MDV not transmitted through the egg, chicks are born free of the disease ◼ The infectious virus matures in the epithelium of feather follicles and infects other birds by inhalation of infected dust or dander 66  MDV-Clinical sings and PM lesions ◼ MDV: usually occur in the form of I-Neural form: (Classical form): Sciatic nerves mainly affected II-Visceral form: is also observed ◼ Enlargement of peripheral nerves up to three times the normal size ◼ Birds are unable to stand, become paralysed (a typical leg-paralysis victim will have one leg extended forward and one leg extended back) ◼ Starvation and death due to an inability to reach feed and water ◼ Wings or neck may be involved 67  Clinical Sings and PM ◼ Visceral form: tumours in various internal organs usually occurs between 16-35 weeks ◼ Infection occur at very young age, but birds can die of MDV near the onset of egg production ◼ Visceral form: signs are less specific and include: -Depression Loss of appetite Loss of weight Anaemia (pale combs) -Dehydration (shrunken combs) Diarrhoea -Tumours internal organs including bursa of Fabricius, ovary, liver & lungs -Death without any clinical signs being noticed Multiple lymphomas in the lung and heart 68  MDV-Clinical sings and PM lesions cont… Cutaneous form: Proliferating lymphocytes deposited in skin producing nodular type lesion Ulcers in the feather follicles recognized readily after plucking as round, nodular 1cm lesions at feather follicles Non feathered leg area gets red – “Redleg Syndrome” Ocular form Iris may be involved and associated with blindness -Left: normal eye (sharply defined pupil and well pigmented iris) -Right: MDV infected: discoloured iris and very irregular pupil due to mononuclear infiltration Perivascular cuffing in the brain 69  Diagnosis of MDV ◼ Proper sampling (Feather follicle) ◼ Detection of viral antigens ◼ FAT of tissues or smears ◼ Electron microscopic examination of species ◼ Detection of viral : PCR ◼ Detection of viral antibodies using ELISA, virus neutralization etc. ◼ Four-fold increase in antibody titer – seroconversion ◼ Virus isolation – Herpesviruses can be grown in embryonated eggs or in cell cultures derived form their natural host ◼ Gross and histopathology -Intra-nuclear inclusion bodies -Syncytia (giant cell formation) 70  Vaccination and Control of MDV ◼ Vaccinate all chicks at one day old; keep chicks from exposure until immunity has developed, about seven days ◼ An avirulent turkey herpesvirus – Heterologous vaccine: HVT may be used as a vaccine: antigenic relationship ◼ An attenuated serotype-1 vaccine is also available ◼ The preferred vaccine is the avirulent TURKEY HERPESVIRUS VACCINE because the virus infects birds productively, yielding a high antigenic dose ◼ 1. Herpesvirus of turkeys- heterotypic lyophilized cell-free preparation ◼ 2. Cell-associated vaccine using Gallid Herpesvirus-3 (does not interfere with maternal antibodies) ◼ 3. Live-attenuated Marek’s disease virus - Gallid Herpesvirus 2 – interferes with Mab ◼ Production of chicken on (all-in-all-out) principle is highly recommended ◼ General sanitation and hygiene measures 71 Comparison between MDV and ALV 72  Duck viral Enteritis (DVE) (Anatid Herpesvirus-1) Severe disease of both wild and domestic waterfowl Anorexia, listlessness, nasal discharge, ruffled dull feathers, adherent eyelids, Photophobia, extreme thirst, ataxia leading to recumbence with outstretched wings and with head extended forward, tremors, watery diarrhea, and soiled vents Multifocal ulceration in the intestinal mucosa Enlarged mottles spleen Mottled thymus with petechial hemorrhage Inflammation and hemorrhage of the proventriculus and gizzards Hemorrhagic intestine: annular band Diffuse petechial hemorrhage in liver Isolation: 1-day-old Muscovy or white Peking ducks, inoculation of CAM of 9-14 day-old embryonated duck eggs Confirmation: inclusion bodies in tissues Contact between susceptible captive waterfowl with wild, free-flying waterfowl should be avoided 73  Psittacid Herpesvirus-1 (Pacheco’s Disease Virus) Acute, contagious and lethal in Psittacinae birds macaws, amazon parrots, monks, and parakeets Old world parrots (Africa/Asia/Europe) - resistant to disease and carrier state Associated with stress, new environment, pet shops The main sources of contraction through the feces, oral and pharyngeal secretions of carrier birds where the virus has shed Healthy carriers can excrete viruses in feces and infect susceptible birds. Acute death, vomiting, bright yellow diarrhea, and neurological signs Hepatomegaly, splenomegaly, and petechial hemorrhages in the pericardium Splenic and liver necrosis with typical intranuclear herpesvirus inclusions No effective vaccine that completely cures Pacheco's disease in infected birds 74  Inclusion body disease of falcons (IBDF) (Falconid HV-1) Pathogenic for American kestrels (Falco sparverius) and great horned owls (Bubo virginianus) in which typical lesions of IBDF are reproduced. The clinical course is short, 24 to 72 hours in duration, and is characterized by mild to severe depression and weakness often accompanied by anorexia. The disease is invariably fatal. The virus has a marked affinity for the Reticuloendothelial system and Hepatocytes, producing focal to diffuse necrosis of infected tissues accompanied by the formation of intranuclear inclusion bodies 75  Elephant Endotheliotropic Herpesviruses (EEHVs) 1A and 1B - cause ~20% mortality in newborn Asian elephants: vague signs like lethargy and inappetence – death in 24h Massive and generalized hemorrhages (hemorrhagic diathesis) due to replication in vascular endothelium Intermittent shedding observed in elephant trunk washes 76  Channel Catfish Virus Disease (CCVD) CCVD infection resulted in the presence of intranuclear inclusions and extensive syncytium formation. -Reduced feeding activity is most likely the first sign and in high mortality for fry and juveniles with severe infection. -The exophthalmos (popeye) is accompanied by hemorrhaging of the fins and ventral abdomen. -Swelling of the abdominal cavity contains fluid contaminants. -Dark and enlarged spleen, Pale and enlarged kidney. -Large numbers of fish aggregate around the edges of hatching troughs or pools, remaining motionless in a head-up, tail-down position. 77  Family Alloherpesviridae Morphologically similar to other Herpesviruses, distinct genome sequences. High level of host specificity, modulates host defenses, long-term latency, epitheliotropic. Cyprinid herpesvirus 3 or Koi herpesvirus Salmonid Herpesviruses 1, 2, and 3 Cyprinid fish, worldwide distribution HV 1: not highly virulent, low mortality. Seasonal disease: spring, autumn HV 2: oncogenic (epithelial tumors), more pathogenic in young salmonids HV 3: mortality in hatchery-reared lake trout in NA Clinical: lethargy, patchy opaque skin lesions. Pale and swollen Clinical gills. Swelling of kidney and spleen. HV2: lethargy, darkening in color, tumors, exophthalmia. Renal Rapid onset of disease following exposure to persistently infected tubular epithelial and liver necrosis fish. HV3:epidermis and fins most affected, cutaneous infections result in high mortality. Pale patches, lethargy. Dx: clinical signs, PCR. Diagnosis isolation of 1 and 2 in salmonid cell lines, confirmed by VNA, and PCR Control: avoidance of seropositive fish Control: avoidance of seropositive fish, screening of adults, disinfection of eggs with iodine solutions, virus-free water supplies. Herpesviruses vaccines 79  2- Family: Parvoviridae-General properties  Parvoviridae includes some of the smallest known DNA viruses  Parvoviruses: small (18-28nm), non-enveloped, icosahedral viruses that contain a linear single-stranded DNA genome Common genera (Parvovirus, Dependovirus, Amdovirus, and Bocavirus) Virons: icosahedral, 25 nm in diameter composed of 60 protein subunits Genome: ss-DNA virus (4-6kb) in size Virus replication: nucleus causing Intranuclear inclusion bodies Stable at pH (3-9) and resist 60C for 60 min Virus hemagglutinates some RBCs 80  Parvovirus genome structure and organization Terminal palindromic sequence -enable ends to make hairpin -facilitate packaging of virions 5’ capped and 3’ polyadenylated VP-1 and VP-2 produced in large amounts NSP1 facilitates -Binding to DNA -Serve as helicase -Serve as endonuclease -Interfere with cellular DNA replication 81  Replication of Parvoviruses ◼ Replication: Rolling hairpin replication ❑ Attachment and entry ❑ Translocation of viral DNA into nucleus ❑ Transcription and translation of viral nonstructural protein and nucleocapsid ❑ DNA replication ❑ Virus assembly (nucleus) ❑ Release from the cell through lysis Classification of the family Parvoviridae 83  Some common Parvovirus diseases N Genus Virus 1 Protoparvovirus -Feline Panleukopenia virus -Mink enteritis virus -Canine parvovirus-2 -Porcine Parvovirus -Parvovris of rodents -Rabbit Lapine parvovirus 2 Amdoparvovirus -Aleutian mink disease virus 3 Aveparvovirus -Chicken and turkey parvovirus 4 Bocaparvovirus -Bovine parvovirus -Canine minute virus (Canine parvovirus-1) Canine Bocavirus-1 5 Dependovirus -Goose Parvovirus -Duck Parvovirus 6 Erythroparvovirus -Parvovirus of nonhuman primates 84  Feline Parvovirus (FPV) Feline infectious enteritis Feline Panleukopenia Virus (Feline Distemper virus) ◼ Highly contagious viral disease of cats: sudden onset, fever, in appetence (loss of appetite), dehydration, depression, vomiting, decreased numbers of circulating white blood cells (leukopenia), and often a high mortality rate ◼ Intrauterine (within the uterus) infection: abortions, stillbirths, early neonatal deaths, and cerebellar hypoplasia (underdevelopment of the cerebellum) ◼ All members of the cat family (Felidae) are susceptible Although cats of all ages are susceptible to feline panleukopenia virus infection, disease occurs predominantly in young recently- weaned kittens due to: Immunosenescence = The gradual deterioration of the immune system, is brought on by natural age advancement. 85  Feline Panleukopenia Virus ◼ Transmission: direct contact with infected cats or their excretions ◼ The early stages of the infection, virus is shed in feces, urine, saliva, and vomitus ◼ Flaccid small intestine with hemorrhage the primary target cells of feline panleukopenia virus and mucosal sloughing Cells of the intestinal crypts ◼ Villi are blunted and fused Lymphopoietic cells of the bone ◼ Cerebellar atrophy and hydrocephalus marrow, thymus, spleen, lymph nodes 86  Diagnosis and treatment of Feline Panleukopenia Virus Hematology: CBC: sharp decrease in the WBCs count Fecal ELISA test: for the detection of parvovirus Serology is not recommended due to the non-discrimination between the infected and vaccinated animals (None DIVA) Intensive care of the infected cats Both modified live and inactivated vaccines are commercially available. Modified live vaccines are used to immunize kittens and inactivated vaccines are safe for pregnant queens. 87  Canine Parvovirus (CPV) ▪It is infectious disease of dogs worldwide, caused by Parvo' is a highly contagious disease characterized by diarrhea that is often bloody ▪ CPV: can survive for long periods (over 1 year) in the environment ▪Prior to 1980, the most canine parvovirus-caused disease was Type 2 (CPV-2) After 1980, CPV-2 was replaced by CPV-2a became more common, and in 1986, another variation called CPV-2b appeared Today, CPV-2b has largely replaced the previous strains as the most common parvovirus-causing disease in the dog In the past few years, a new strain, CPV-2c, has been detected. 88 CPV- Clinical signs, host range and transmission Host range of CPV ▪ Dogs, especially less than 12 weeks of age. ▪ Can also occur in unvaccinated or improperly vaccinated adult dogs Mode of transmission of CPV ▪Fecal-oral route and virus that persists on fomites. ▪Virus is shed for a few days before the onset of clinical signs ▪Transmission of CPV is predominantly by: Iatrogenic due to medical interference, such as transmission by contaminated needles. 89 The life cycle of Canine parvovirus 90  Pathogenesis: Virus Starts replication in lymphoid tissues of oropharynx, mesenteric lymph nodes, bone marrow and thymus and viremia developed GI tract Bone Marrow Epithelium of the tongue, oral cavity, Lymphopenia &Neutropenia and esophagus, and intestinal tract, and also due to sequestration of especially the germinal epithelial cells neutrophils in damaged of the intestinal crypts gastrointestinal tissue. Malabsorption and increased Important points to Know intestinal permeability Dogs with canine parvoviral enteritis have Secondary evidence of disordered coagulation bacterial infection Infection of the dam by CPV-2 variants early in Results in clinical signs of fever, gestation can lead to infertility, resorption, or lethargy, inappetence, vomiting, abortion diarrhoea, rapid dehydration, and Puppies that are Infected in utero or up to 2 abdominal pain. Diarrhoea is often weeks of age may develop viral myocarditis liquid, foul-smelling, and may contain streaks of blood or frank blood  Canine Parvovirus (CPV) ◼ Highly contagious virus of dogs affects intestines and causes sloughing of the inner layers of the intestine ◼ “Intestinal form”: vomiting and diarrhea Severe hemorrhagic diarrhea in dogs ◼ “Cardiac form”: very young pups (less than 8 wks of age) affect the heart muscle, often resulting in sudden death. ◼ Prenatal time: CPV target cells are cardiomyocytes Pale streaking of the myocardium 92  Pathogenesis of the Canine Parvovirus (CPV) Tropism for intestinal epithelium leads to the collapse of intestinal villi, epithelial necrosis, and hemorrhagic diarrhea—clinical signs of gastroenteritis Depletion of lymphocytes and compromised gastrointestinal system may lead to bacteremia by normal gut flora: E.coli, which can be fatal. A: Normal intestinal villus showing cellular differentiation B: CPV infected villus showing collapse and necrosis of the intestinal villi 93  CPV infection risk associated factors The severity of clinical signs depends on: Virus strain Host immunity, is affected by stressors such as weaning and overcrowding, maternal antibody Presence of concurrent infections such as other enteric viral and parasitic infections CPV, replicate and destroy crypt epithelial cells Mechanism of Death 1. Diarrhea and vomiting, extreme dehydration: SHOCK 2. Loss of intestinal barrier: bacterial invasion: SEPTIC SHOCK 94  Some necropsy and histopathology findings -Canine Parvovirus (CPV) Small intestine of dog died suddenly of enteritis Note: discoloration of intestinal wall and fibrin on the serous surface Pathology of the small intestine of dog died due to CPV infection showing -Villi collapse -Crypt lamina are dilated and filled with necrotic debris 95  Diagnosis of CPV ▪Clinical signs and symptoms: the sudden onset of foul-smelling, bloody diarrhoea in a young dog (under 2 years of age) is often considered indicative of CPV infection ▪Laboratory tests ❑CBC (leukopenia, neutropenia, and Lymphopenia) ❑Abnormal coagulation test ❑Cardiac troponin-I is a plasma marker for myocardial damage. ❑Biochemical tests (often shows Hypoproteinemia, Hypoalbuminemia, and Hypoglycemia) ▪Virus detection ❑ Fecal ELISA antigen tests(specific but less sensitive) ❑ PCR methods. ▪ Antibody Detection ❑Serology is not the best method to diagnose CPV infection because most dogs are vaccinated against it or have been previously exposed to the virus Infection or vaccination with one subtype of canine parvovirus (CPV) confers immunity against the other subtypes. 96 97  Diagnosis & control of Parvoviruses ◼ Clinical Signs and PM ◼ Laboratory diagnosis -Fecal enzyme immunoassays -HA test (pig, cat, monkey) RBCs -Detection of virus by EM -PCR: amplification of viral DNA -Serology: ELISA Control: various types of vaccines are commercially available 98  Prevention of CPV-Vaccines ▪Both attenuated live and inactivated CPV vaccines are available ▪Attenuated live vaccines: should never be administered to pregnant bitches because they may cause disease in the developing fetus. ▪Monovalent CPV vaccines: administered by the intranasal route and commercially available ▪The age at which a pup should be vaccinated successfully can be predicted through the determination of the MDA titters by serologic tests. ▪Pups from a bitch with a low protective antibody titer to CPV can be successfully immunized by six weeks of age, but in pups with a very high titer to CPV, MDA may persist much longer. ▪Pups of unknown immune status can be vaccinated with a high-titer-attenuated live CPV vaccine at 6, 9, and 12 weeks of age 99 FPV/CPV 100  Porcine Parvovirus (PPV) The virus is lymphotropic and live/persists in B and T cells for a long time If the infection occurs in the first month of pregnancy, the fetal pigs will die and be absorbed From day 30-70 of the pregnancy- fetal pigs die and are mummified After 70 days, the growing pigs may be able to fight off the infection SMEDI SMEDI Stillbirth Mummification Embryonic death Infertility 101 Differential diagnosis of Porcine Parvovirus (PPV) infection Aujeszky’s disease Leptospirosis Foot-and-mouth disease Classical swine fever Japanese encephalitis Porcine brucellosis Porcine reproductive and respiratory syndrome (PRRSV) Porcine enterovirus infection Vesicular stomatitis 102 Aleutian mink disease virus (AMDV) Aleutian disease (AD) is known to produce clinical signs in mink and ferrets only In adult mink, AD is a persistent, slowly progressive AMDV infection in which a dysregulated immune system A post-infectious antibody response causes an immune complex-mediated vasculitis Perivascular and glomerular immune complexes causing membranoproliferative glomerulonephritis Mononuclear cells may surround the vessel, and connective tissue proliferation and necrosis in the tunica Elastica media narrow the lumen. Serum protein electrophoretic patterns The serum of infected animals shows a Polyclonal Gammopathy: the gamma globulin accounts for 62.4% of serum proteins. The normal level is 14.3% Vaccine increase severity of AMD Aleutian mink disease virus Immunosuppression decrease severity of AMDV and Goose parvovirus do not agglutinate RBCs 103 Equine parvovirus, named Equine parvovirus hepatitis (EqPV-H)- &Theiler’s Disease EqPV-H is hepatotropic and pathogenic, but the great majority of recently infected horses (within 4-12 weeks) have non-clinical hepatitis with 2 or more weeks of elevated serum liver enzymes Two modes of transmission are recognized in horses: Biologic transmission: through the administration of biologic products containing EqPV- H. To date, EqPV-H has been identified in tetanus antitoxin (TAT), botulinum antitoxin, Streptococcus equi antiserum, pregnant mare’s serum, allogenic stem cell preparations and equine plasma products. Cases generally present 4-13 weeks after receiving equine biologic products. Non-biologic transmission sporadically in horses with no history of receiving biologic products. Clinical forms: Asymptomatic infection: Most horses infected with EqPV-H remain asymptomatic. Clinical hepatitis: It is estimated that approximately 2% of infected horses will develop clinical liver disease, ranging from mild illness to acute fulminant liver failure 104  Goose parvovirus (GPV) Derzsy's disease Goose hepatitis, Goose plague Goose parvovirus infection is a highly contagious, fatal disease of 8–30-day old goslings (Derzsy’s disease), which causes Hepatitis and Myositis. Excreted in large amounts in the feces of infected birds Transmission of the virus via eggs laid by infected breeder geese. Mortality can reach 100% in birds infected in the hatchery ocular and nasal discharge, a profuse white diarrhea Birds may stand in a “penguin-like” posture due to the accumulation of ascitic fluid in the abdomen. The heart is characteristically rounded at the apex, with a pale myocardium Cowdry type-A Intranuclear inclusion bodies. 105