Prelim 2 Viruses- Herpesviruses II - Herpesviruses in Cattle

CS: Respiratory dz (IBR), Genital dz (IPV/IPB), Abortion, High fever, Milk drop, Diarrhea
Acronym: BoHV-1
Natural Host: Cow
Subfamily: alpha

Clinical Signs, Acronym, Natural Host, Subfamily of Bovine Herpesvirus 1

CS: Mammilitis
Acronym: BoHV-2
Natural Host: Cow
Subfamily: alpha

Clinical Signs, Acronym, Natural Host, Subfamily of Bovine Herpesvirus 2

CS: Malignant Catarrhal Fever (MCF)
Acronym: AlHV-1
Natural Host: Wildebeest
Disease in: Cow
Subfamily: gamma

Clinical Signs, Acronym, Natural Host, Subfamily of Alcelaphine Herpesvirus 1

CS: Malignant Catarrhal Fever (MCF)
Acronym: OvHV-2
Natural Host: Sheep
Dz in: Cow
Subfamily: gamma

Clinical Signs, Acronym, Natural Host, Subfamily of Ovine Herpesvirus 2

CS: Aujeszky’s Disease
Acronym: PRV
Natural Host: Pig
Disease in: Cow
Subfamily": alpha

Clinical Signs, Acronym, Natural Host, Subfamily of Pseudorabies Virus

General Features:
Cattle
Alphaherpesvirus
Most common viral infection in cattle, more common in dairy/feedlot than free range
Resp. entry → Infectious Bovine Rhinotracheitis (IBR) and Abortion
Genital entry → Infectious Pustular Vulvovaginitis (IPV) or Infectious Balanoposthitis (IPV)
Naiive herd morbidity: up to 100%
Immune herd morbidity: up to 20%
Mortality low (0-10%)
Monitored disease

General Features of BoHV-1

Pathogenesis:

Cattle
1. Primary Replication in mucosal surfaces (IBR/IPV)
2. Bloodstream (viremia)
3. Pregnant uterus (abortion)
4. Trigeminal & sacral ganglia (latency)

Pathogenesis of BoHV-1

Infectious Bovine Rhinotracheitis
CS:
Cattle
Coughing, sneezing, depression, inappetence, excessive lacrimation, marked conjunctivitis, fetid odor to breath (Oronasal ulcers), oronasal secretions (clear to mucopurulent), Abortion (4-7mo gestation), “red nose”

Clinical Signs of IBR (BoHV-1)

Infectious Pustular Vulvovaginitis
CS:
Cattle
Fever, depression, inappetence, Vesicles/pustules on vulvar skin/vaginal mucosa, potential ulcerations of vaginal mucosa w/ overlaying pseudomembrane, frequent micturition, tail held away from vulva

Clinical Signs of IPV (BoHV-1)

Infectious Balanoposthitis
CS:
Cattle
Balanatis (Inflam. of glans penis), Posthitis (inflam. of prepuce (foreskin)), Vesicles to ulcers, bulls refuse to breed

Clinical Signs of IBP (BoHV-1)

Diagnosis:
cattle
CS (hard to differentiate from other causes of bovine resp. dz complex ‘shipping fever’)
Virus isolaion from nasal/genital swabs
ELISA to detect BHV-1 antibodies in bulk milk, milk from individual vows, or ID latent carriers (bulls)

Diagnosis of BoHV-1

Prevention:
cattle
Sterilize AI equipment of fomites, ensure semen is virus-free
Steroids can cause reactivation, used to ID carrier bulls
Steroid admin can cause herd outbreaks if herdmates are naiive/unvaxxed
Dangerous to ship infected cattle, esp. w/ contact w/ pregnant cattle → Stress causes reactivation

Prevention of BoHV-1

Control:

cattle
Vaccination with Modified Live virus (Parenteral or intranasal), or inactivated vaccine (Parenteral)
Marker vaccines (gE)

Control of BoHV-1

General Features:
Cattle
Alphaherpesvirus
USA → Bovine Herpes Mammilitis (BHM)
Africa → BHM, Pseudo-Lumpy Skin Disease (PLSD)
Pathogenesis & Epidemiology not fully elucidated

General Features of BoHV-2

Epidemiology & Pathogenesis:

cattle
US → Transmission via insects (mechanical vectors), fomites (milking machines), resp route?
Africa → Transmission via insects, wild bovids serve as reservoir?

~ 7 days after infection, vesicles appear → Slow-healing ulcers → Latency

Epidemiology & Pathogenesis of BoHV-2

CS:
Cattle
Skin lesions limited to teats/udder of lactating cows
Teat swelling & ulceration
Ulceration of skin of mammary gland
Pain & swelling prevents milking, dec. milk production
Milk retention → Bacterial Mastitis

DDx: Cowpox

Clinical Signs of Bovine Herpes Mammitis (BHM, BoHV-2)

CS:
cattle
Appearance of multiple edematous nodules in skin, esp. neck (also back, head, chest, and tail regions)
Nodules painful on palpation
Superficial skin layer over nodule becomes necrotic w/ serous exudation, followed by scab formation

DDx: Lumpy skin disease (pox)

Clinical Signs of Pseudo-Lumpy Skin Disease (PLSD, BoHV-2)

Diagnosis:
cattle
CS
Virus Isolation
Biopsy: intranuclear inclusion bodies (unlike pox), hydropic (water-filled) degeneration of skin cells

Diagnosis of BoHV-2

Control:
cattle
No vaxx
Good hygiene
Immunity lasts 2 yrs after natural infection

Control of BoHV-2

General Features:
Fatal disease in cattle, deer, antelope, and buffalo
Caused by several ruminant gammaherpesviruses
Viruses do not cause disease in natural host
(AlHV-1, Wildebeest and OvHV-2, sheep)
Reportable disease

General Features of Malignant Catarrhal Fever (MCF)

Epidemiology

Circulates in Africa, US zoos
No CS in natural host (wildebeest, topi, hartebeest)
Transmission to cattle upon close contact, especially around calving time of dam (ie, state fairs)
Morbidity in cattle is LOW, does not spread btwn cattle
Mortality in affected animals VERY HIGH

Epidemiology of AlHV-1

Epidemiology:
Circulates mostly in Western US
No CS in natural host (sheep)
Transmission to cattle upon close contact w/ sheep, esp. around lambing time

Epidemiology of OvHV-2

Pathogenesis:
Not fully understood
Primary infection → Resp. mucosa → Resp. signs

Lymphocyte-associated viremia → Massive increase in T-cells (helper & cytotoxic) → Lymphadenopathy

T-lymphocyte hyperplasia (in lymphoid organs & periphery) → Cytotoxic effects on cells

Lymphocytes deliver virus to endothelial cells → Secondary replication → Vasculitis 

Pathogenesis of MCF

CS:
cattle
High fever, depression, profuse nasal & ocular discharge
Generalized lymphadenopathy, extensive mucosal erosions
CNS signs (ataxia, nystagmus, head pressing)
Bilateral ophthalmia (PATHOGNOMONIC: Corneal opacity in the center, spreading to the periphery, leading to blindness
Death (~ 1 wk in cattle)

Clinical Signs of MCF

Lesions:
cattle
Vasculitis with necrosis, hemorrhage, and edema
LN may be edematous, hemorrhagic
Widespread erosions and hemorrhage (nasal turbinates, larynx, gut)

Histo: Lymphoid cell proliferation, esp. around small blood vessels, w/ multifocal necrosis and hemorrhage

Lesions of MCF

Diagnosis:
cattle
CS (bilateral ophthalmia), epidemiology/hx
PCR to detect vital DNA, not very specific 
ELISA to detect antibodies → Not usually helpful since animal is usually dead before mounting antibody response
Virus isolation difficult 

DDx: “Head and eye disease" in cattle
Blue Tongue Disease
Bovine Viral Diarrhea 
Vesicular stomatitis 
Foot and Mouth Disease

Diagnosis of MCF

Control:
cattle

No vaxx

Keep cattle away from sheep, african ungulate hosts, esp. at lambing/calving time

Control of MCF

Most common viral infection in cattle
High morbidity, low mortality
Two infection/transmission routes:
1. Respiratory → IBR, Part of ‘shipping fever,’ abortion
2. Genital → IPV, IBP

Take Homes for BHV-1

Cause of BHM (US, Africa) and PLSD (Africa)
Pathogenesis still debated

Take Homes for BHV-2

Two etiological gammaherpesviruses: AlHV-1 (Wildebeest) and OvHV-2 (sheep)
No disease in natural host, fatal in cattle
Transmission around calving/lambing time, keep them separated
Respiratory signs, lymphadenopathy, bilateral ophthalmia

Take Homes for MCF