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virology > Multisystemic viral diseases of ruminants > Flashcards

Multisystemic viral diseases of ruminants Flashcards

1
Q

Bovine Herpesvirus-1 also known as?

A

Infectious bovine rhinotracheitis (IBR), redness, necrotic rhinitis, pustular vulvovaginitis (IPV), Infectious pustular balanoposthitis

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2
Q

Family and genus of bovine herpesvirus-1

A

Family Herpesviridae

Alphaherpesvirus

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3
Q

Primary host of IBR/bovine herpesvirus-1

A

BEEF cattle (feedlots, range)

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4
Q

Primary host of infectious pustular vulvovaginitis (IPV)

A

Still an infection with bovine herpesvirus-1… just like IBR
Disease of DAIRY cattle

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5
Q

Age range of affected cattle for IBR or IPV

A

No age range preference

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6
Q

What has caused an increase in incidence of BHV-1?

A

Intensive farming (both beef and dairy)

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7
Q

IBR/IPV/BHV-1 has a ______ mortality and _____ morbidity

A

High morbidity, low mortality

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8
Q

Do IBR and IPV have the same serotype of BHV-1?

A

Yes, same serotype but can be differentiated genetically

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9
Q

Transmission of IBR

A

Transmitted aerosol mostly, but also direct and indirect mucosal contact with infected secretions or abortions

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10
Q

Transmission of IPV

A

Sexually… close proximity of animals enhance transmission

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11
Q

Clinical signs/lesions of BHV-1

A

Respiratory form (sudden onset of fever accompanied with profuse nasal and ocular discharge) for IBR

Genital form for IPV

Abortion (weeks after infection, last trimester)

Ocular form (conjunctivitis)

Systemic form (seen in calves less than 2 weeks old)

CNS form

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12
Q

Respiratory form of BHV-1 (IBR only)

A

Characterized by sudden onset of fever accompanied by profuse nasal and ocular D/C

Nasal discharge starts serious but becomes mucopurulent with crusting around bares… accompanied by coughing, increased RR, increased lung sounds, and open mouth breathing

Severely inflamed nasal terminate and nasal mucosa (red nose) with NECROSIS, ulceration, and plaques (necrotizing rhinitis)

Very high morbidity, low mortality

Predisposes cattle to infection with bacteria(mannheimia) and the resultant viral/bacterial infection is known as SHIPPING FEVER

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13
Q

Genital form of BHV-1 (IPV only)

A

Lesions seen on reproductive tract of cows and bulls develop 2-3 days following coitus

In cow, frequent urination, tail switching, slight vaginal discharge… small postures, small white necrotic areas and ulcers seen on Velva and pens

Lesions heal easily.. NO INFERTILITY problems

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14
Q

Abortion in BHV-1

A

Occurs weeks after infection… usually in last trimester of pregnancy

It is a SEQUELA of respiratory infection

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15
Q

Ocular form (winter pinkeye) of BHV-1

A

conjunctivitis and profuse lacrimation, often in absence of respiratory disease

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16
Q

Systemic form of BHV-1

A

Seen in newborn calves less than 2 weeks old

Calves infected in-utero or soon after birth- OCCURS IN CALVES THAT HAVE NO ANTIBODIES TO BHV-1

Acute disease characterized by high fever, anorexia, respiratory distress… MORTALITY IS VERY HIGH

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17
Q

CNS form of BHV-1

A

Seen sporadically in cattle

incoordination, rumor, convulsion, HIGH CASE FATALITY

Bovine herpes encephalitis is usually caused by bovine herpesvirus-5, but can be observed with BHV-1

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18
Q

What usually causes bovine herpes encephalitis?

A

Bovine herpesvirus-5, but can be seen with bovine herpesvirus-1 as well

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19
Q

Which forms of BHV-1 have high case fatality?

A

CNS form and Systemic form

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20
Q

Pathogenesis of BHV-1

A

Incubation period is 1 week, causes a LATENT INFECTION

BHV-1 infest moist mucus membranes… mucosal lesions are usually ULCERATIVE, INFLAMMATORY, and NECROTIC!!!

Replication starts locally in mucosal cells, spreads to submucosa, infects sensory nerves and taken up by Macs

Virus migrates up the sensory nerve and becomes LATENT in nuclei of the neurons (ganglia)

Necrosis of mucosa

Infected Macs carry virus to LN–> infect and go latent in T-Lymphocytes… infected lymphocytes can cause placental and fetal infection, resulting in abortions

Viral recrudescence in latent infected neurons and t cells allow virus to re-infect mucosa, replicate, and spread to other animals… or the placenta (if T-cells)

BHV-1 infected lung Macs cannot function properly, so bacteria replicate and cause secondary infections (SHIPPING FEVER)

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21
Q

Diagnosis of BHV-1

A

BHV-1 is on DDx in all upper respiratory tract infections, abortions, and vaginitis

Major clin signs- mucosa NECROSIS, inflammation, and ulceration in nasal passages and trachea

Aborted fetuses show focal disseminated necrotizing hepatitis with IN inclusions

If suspected, submit mucosal swabs in transport media (shipped frozen) to confirm by PCR!!!!

Submit fresh fetus or fetal liver if abortion (FA or IHC can be done on fetus liver)

Serology (paired samples, look for seroconversion)

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22
Q

Immunity to BHV-1

A

Mucosal immunity is very important to prevent infection

seropositive animals can still be infected… but probably not clinically ill

BHV-1 can recrudesce even in the presence of circulating antibodies

Vaccines given IN more effective at preventing infection than those given IM

Both CMI and humoral immunity are important (CMI for recovery from infection, humoral immunity to prevent re-infection)

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23
Q

Control/treatment of BHV-1

A

Symptomatic treatment

Maternal Ab can persist for up to 6 months, so interference with vaccination

VACCINES AVAILABLE (both MLV and inactivated)

    - MLV given either IN or parenterally
    - vaccinate beef calves 2-3 weeks before weaning, heifers and bulls 2 weeks before breeding, feeder cattle 2 weeks before entering feedlot (annual revaccination)
    - MLV contain "temperature sensitive IBR"- these replicate in upper respiratory tract... SAFE for pregnant cows
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24
Q

Bovine leukemia virus also known as

A

Bovine lymphosarcoma or Enzootic Bovine Leukosis

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25
Q

Family and genus of bovine leukemia virus

A

Family retroviridae and is a deltaretrovirus

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26
Q

Susceptible species to BLV

A

ONLY CATTLE ARE NATURALLY INFECTED WITH BLV

Sheep are also susceptible to lymphoma when experimentally infected

There is a MARKED gene3tic predisposition to BLV in cattle

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27
Q

Source of bovine leukemia virus

A

Infected cattle- seropositive persistently infected cattle

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28
Q

How is BLV often introduced to a herd?

A

Newly acquired persistently infected cattle

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29
Q

Highest incidence of BLV age range

A

4-8 years old

Few animals under 2 years develop Enzootic bovine leukosis

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30
Q

Transmission of BLV

A

Primarily via blood inoculation

*BLV is in the leukocytes of seropositive cattle

insect vectors may play a role in transmission

  • blood transfusion, dirty needles, vaccination… can transmit disease
  • -transmission of leukocytes in blood!!
  • dethroning is considered very important in transmission
  • **gloves used for rectal exams can transmit virus
  • PROLONGED CLOSE PHYSICAL CONTACT BETWEEN ANIMALS is essential for successful transmission- mingling of heifers with adult herd is important because that is when replacement heifers become infected

-nursing can spread virus but not important source of infection

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31
Q

Clinical signs of Bovine Leukemia Virus

A

2 major forms of disease:

  • Lymphosarcoma
  • Persistent lymphocytosis

Also see sporadic bovine leukosis (LSA seen in cattle under 3 years old… Juvenile LSA in calves 1-6 months, Thymic LSA, and cutaneous LSA in 1-2 year old animals… animals with sporadic bovine leukosis are BLV seronegative)

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32
Q

BLV induced Lymphosarcoma or Enzootic Bovine Leukosis signs

A
  • BLV induced LSA is HIGHLY FATAL, systemic malignant neoplasia characterized by development of AGGREGATIONS OF BLV INFECTED NEOPLASTIC LYMPHOCYTES in almost any organ
  • **Affected cattle are BOTH SEROPOSITIVE AND PCR POSITIVE

-decreased appetite, decreased milk production, weight loss, and anemia, and enlarged superficial LN

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33
Q

Persistent Lymphocytosis caused by BLV

A
  • benign lymphoproliferative condition seen in HEALTHY BLV infected cattle
  • these animals show NO OVERT SIGNS, but have a marked increase in circulating lymphocytes
  • these animals rarely develop LSA
  • ALL BLV infected cattle (whether healthy, LSA or persistent lymphocytosis) will be seropositive and PCR positive for BLV
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34
Q

BLV-induced sporadic bovine leukosis

A

lymphosarcoma in cattle under 3 years
Juvenile LSA in calves 1-6 months
thymic LSA or cutaneous LSA in calves 1-2 years

Animals with sporadic bovine leukosis are BLV SERONEGATIVE

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35
Q

Pathogenesis of Bovine Leukemia Virus

A

Incubation period is 2-4 years (for either LSA or PL)!!!

  • BLV infects and transforms B-lymphocytes and integrates in DNA, forming a PROVIRUS
  • there is NO VIREMIA and NO BLV IN SECRETIONS
  • transmission is via infected lymphocytes
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36
Q

Infectivity of BLV

A

If 100 cattle are infected experimentally, only 30% will become PCR positive and seropositive… of these 30,

-66% will remain asymptomatic healthy carriers (no PL or LSA)
-30% will develop PL (with or without LSA)
3% will develop LSA

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37
Q

Diagnosis of BLV

A

PCR- very sensitive and used for blood or bulk milk

Serology (ELISA)

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38
Q

Control of BLV

A

Testing and slaughter

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39
Q

Bovine Immunodeficiency virus

A

lentivirus, associated with lymphocytosis

Many animals are seropositive for BIV but no specific condition has been associated with BIV… except suspect immunosuppression

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40
Q

Bovine Viral Diarrhea synonyms

A

Mucosal disease

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41
Q

BVDV family and genus

A

Family Flaviviridae

Genus Pestivirus

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42
Q

Variations of BVDV

A

2 genotype

  • BVDV type 1
  • BVDV type 2

2 biotypes of BVDV

  • Non cytopathic (NCP)
  • Cytopathic (CP) biotypes

Many different strains of BVDV exist within both the genotype and biotypes of BVDV- these strains differ in pathogenicity

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43
Q

Do BVDV strains cross-react?

A

All strains of BVDV are antigenically similar and cross-react serologically

44
Q

Transmission of BVDV

A

Affects cattle worldwide
-prevalence of BVDEV is high in cattle, buffalos
Several disease forms of BVDV

Transmission is by DIRECT CONTACT (mucosal contact with infected urine, feces, excretion) or TRANSPLACENTALLY

45
Q

Major source of infection for BVDV

A

Persistently infected cattle that secrete virus constantly

  • prevalence of PI animals in herds is low (1-2%)
  • prevalence of seropositive cattle in a herd with one or more PI animals is 87%
  • in a seropositive beef herd with PI animals, about 10% of calves will be PI calves (poor doers, survive only 1 year)
46
Q

What animals are most susceptible to BVDV

A

Young and unvaccinated cattle are most susceptible… they become fully susceptible to disease after losing maternal Ab by 3-8 months of age

**Wild rums, sheep, and goats and pigs can also be subclinically infected with BVDV

47
Q

Clinical signs of BVDV/forms of disease

A

Disease forms depend on environment, age of animals, and infection with specific serotype

1) Benign Infection (Bovine virus diarrhea)
2) Parachute highly fatal diarrhea
3) Fatal Mucosal Disease
4) Thrombocytopenia and Hemorrhagic Disease
5) Reproductive Failure
6) Congenital abnormalities
7) Chronic BCD infection and unthrifty PI calves
8) Immunosuppression resulting in respiratory disease with secondary bacterial infection

48
Q

BVDV disease- Benign Infection

A

Called “bovine virus diarrhea”

  • occurs in immunocompetent seronegative calves and young adults
  • inapparent infections… if seen, mild fever, leukopenia, diarrhea
  • rapid recovery within a few days and development of Neutralizing Ab
  • high morbidity and low mortality
49
Q

BVDV disease- Peracute highly fatal diarrhea

A

Severe form of disease characterized by RESPIRATORY and ENTERIC signs

  • usually caused by BVD type II
  • respiratory infection, profuse diarrhea, and high fever, oral erosions and mucosal lesions seen
  • all ages of animal affected, mortality highest in younger calves
  • infection can last several weeks and outbreak progresses slowly
50
Q

BVDV disease -Fatal Mucosal Disease

A
  • SEEN ONLY IN PI ANIMALS*
  • disease of younger animals <2 years
  • signs include profuse watery diarrhea, mucopurulent nasal discharge, erosive/ulcerative stomatitis, dehydration, and death
  • 100% case fatality rate**
51
Q

BVDV disease- Thrombocytopenia and Hemorrhagic disease

A

-associated with NCP BVDV type II virus
-bloody diarrhea, petechial/ecchymosis on mucosa, epistaxis, prolonged bleeding
-severe thrombocytopenia <25k platelets
Case fatality 25%

52
Q

BVDV disease- Reproductive failure

A

Conception failure, fetal mummification, abortion, premature birth and stillbirths

53
Q

BVDV disease- congenital abnormalities

A

Occurs when gvirus infects fetus during period of organogenesis
-cerebella hypoplasia and hydranencephaly is common
-calves unable to stand and walk normally after birth
Can also lead to calf blindness

54
Q

BVDV disease- chronic BVD infection and Unthrifty PI calves

A

Animals that don’t completely recover from infection can develop diarrhea, evacuation, bloat, hoof deformities, erosive stomatitis, and shabby lesions in perineum, scrotum, and interdigital cleft

-calves born PI may be smaller and fail to grow normally… Usually develop fatal pneumonia or fatal mucosal disease (these calves ARE SERONEGATIVE FOR BVDV)

55
Q

BVDV disease- Immunosuppression resulting in respiratory disease with secondary bacterial infection

A

Seen mostly in feedlots when calves are grouped together and stressed

56
Q

Pathological signs of BVDV

A

Abnormalities mostly seen in alimentary tract

  • shallow erosions in mouth, esophagus, forestomach, abomasum, and cecum
  • in mouth, mucosa has cooked appearance with grayish colored epithelium

-histopath- peyer’s patches depleted of lymphocytes with little inflammation in ulcer vicinity

57
Q

Pathogenesis of BVDV

A
  • replicates on mucosal surface and tonsils, spreads to LN, infects lymphocytes, and spreads to all lymphoid tissues and organs… necrosis of lymphocyte-associated gut wall tissues and of mucosal epithelium is basis for lesions observed
  • pathogenesis depends upon a multitude of interactive factors (age, immune status, stress, secondary infections)
58
Q

BVDV infection of pregnant cattle and fetal infection

A

Exposure of cattle to virus at estrus may lead to failure of conception… insemination with BVD infected semen can lead to poor conception… However, after the animal has seroconverted, conception is normal and calf is born healthy
-infection during embryonic period leads to decreased conception rate and return to estrus

  • infection of fetus during early fetal life leads to death of fetus (mummification/abortion), congenital abnormalities, or persistent infections
  • persistent infection of fetuses occurs when the fetus is infected during early fetal life with a NCP strain… fetus recognizes virus as self… born normally but secretes virus constantly
59
Q

PI calves with BVDV

A

-persistent infection of fetuses occur when fetus is infected during early fetal life with NCP strain
-PI calves will develop mucosal disease when 1)NCP virus mutates to CP virus… or 2)infected with CP virus that is antigenically similar to NCP virus
~mucosal disease can occur within the first 2 years of life

  • PI calves will develop normal immune response to other BVDV strains that are antigenically different to the one they ware persistently infected with (even respond to vaccines)
60
Q

Infection of the fetus

A

Infection of a fetus early (45-125 days) results in death to fetus- mummification or abortion

  • infection of a fetus during period 125-175 days of gestation will result in congenital defects
  • infection of a fetus after 180 days of gestation results in fully competent immune response by fetus and elimination of the virus–> calf born with Ab to virus and is virus free
61
Q

Diagnosis of BVDV

A

Leukopenia in acute mucosal disease

EROSIVE LESIONS (not vesicular)

Virus isolations (FA or IPX)

- NCP BVDV does not cause CPE/Inclusions
- whole blood sample is best sample for virus isolation****
- Feces is not a good sample to submit****

Direct virus identification in tissues- FA, IHV, PCR

Serology on paired samples

62
Q

Treatment and control of BVDV

A

Detection and elimination of PI animals from herd

Vaccinate breeding animals to prevent fetal infection, vaccinate calves at weaning

Prevent introduction of PI animals into a non-infected herd

63
Q

Alcephaline Herpesvirus-1 and Ovine Herpesvirus-2 synonyms

A

Malignant catarrhal fever

-2 forms : African form and US/European form

64
Q

Species affected by malignant catarrhal fever

A

Considered one of the most important diseases of farmed deer

Also affects cattle

65
Q

Malignant catarrhal fever characteristics

A

Erosive stomatitis, gastroenteritis, erosions of the upper respiratory tract, conjunctivitis, encephalitis, and lymphadenopathy

Occurs sporadically (1-2 cases per farm)

***low morbidity, HIGH MORTALITY

66
Q

Malignant catarrhal fever family and genus

A

Family herpesviridae, gens gamma-herpesvirus

alcelaphine herpesvirus-1 infects wildebeest naturally
Ovine herpesvirus-2 infects sheep naturally

67
Q

2 forms of Malignant catarrhal fever

A

1) African form
- associated with AHV-1 in wildebeest
- disease is endemic in Africa, but also occurs in US (zoos, exotic animal farms)

2) Sheep associated aka US-European form
- caused by OHv-2 of sheep, endemic in US
- OHV-2 is transmitted from sheep to cattle, bison, and deer in the US
- wildebeest and sheep are inapparent carriers of the virus

68
Q

Transmission of MCF (Malignant catarrhal fever)

A

Transmission from carrier animals to cattle is by DIRECT contact

  • wildebeest transmit AHV-1 to cattle and other rums at calving season though direct contact with wildebeest placenta and new-born wildebeest calves
  • OHV-2 is transmitted from sheep all year round in the US… not associated with lambing, and young lambs do not transmit OHV-2
  • cattle to cattle transmission cannot be accomplished except by blood transfusion

Cattle and deer sometimes survive for a few weeks are thought capable of transmitting the virus during that time period before they die

MCF occurs SPORADICALLY in cattle, deer, and bison in the US… associated with VERY HIGH CASE FATALITY

69
Q

Can cattle transmit MCF to other cattle?

A

NO

Only way to transmit disease between cattle is via blood, and cattle are not considered contagious between cattle

70
Q

Clinical disease caused by Malignant Catarrhal fever

A

1) head and eye form (most common)
2) Parachute and alimentary form
3) Mild Form

71
Q

Malignant Catarrhal fever- head and eye form of disease

A

Most commonly seen

  • sudden onset of HIGH fever
  • extreme depression, anorexia, photophobia, nasal and ocular discharges, corneal opacity, diarrhea
  • lameness is also noted along with enlarged LN
  • CORNEAL OPACITY (chronic bilateral stromal keratitis) begins at limbs and progresses centrally, accompanied by blepharospasm and congestion of scleral vessels

Erosions seen on mouth soft palate, tongue, and gums. (Nasal mucosa is red, necrotic, and covered with fibrinopurulent exudates)

CNS signs may appear (head pressing, incoordination)

Death 7-10 days after onset of symptoms

72
Q

Malignant Catarrhal fever- peracute and alimentary tract form of disease

A

Common in deer
-characterized by high fever, dyspnea, and acute gastroenteritis

Death within 1-3 days

73
Q

Malignant Catarrhal fever- mild form of disease

A

Transient fever and mild erosions

74
Q

Pathogenesis of Malignant Catarrhal fever

A

Virus infects lymphocytes, causes a lymphoproliferative and vascular lesions > there is widespread proliferation of lymphocytes and multifocal areas of necrosis around small arteries that undergo fibrinoid necrosis of the muscle wall > the PATHOGNOMONIC LESIONS of MCF is a necrotizing vasculitis and perivascular cuffing (especially in the brain. Lesions may be immune mediated as a result of CTL attacking and killing the vascular endothelial cells

75
Q

What is the PATHOGNOMONIC lesions of Malignant Catarrhal fever?

A

Necrotizing vascuitis and perivascular cuffing

76
Q

Diagnosis of Malignant Catarrhal Fever

A

Clinical signs- sporadic disease with low morbidity and high mortality

At necropsy- erosions and hemorrhages throughout the intestine and oral cavity… generalized lymphadenopathy

Submit various organs (brain, LN, mucosa) in formation for histopath–> necrotizing vasculitis is PATHOGNOMONIC

Blood for PCR

Carrier animal detection through ELISA for AB detection

77
Q

Bluetongue virus synonyms

A

Range stiffness

sore muzzle
mycotic stomatitis

78
Q

Bluetongue Virus family and genus and morphology

A

Family Reoviridae

Genus orbivirus

Non- enveloped, double capsid, double stranded RNA virus with segmented genome

79
Q

Serotype of Bluetongue Virus

A

25 serotype, many seen in the US

Serotype share a common internal antigen (group specific Ag) that can be detected by immunodiffusion

External antigens differentiate the various serotypes (type-specific Ag)

reassortment of genes can occur between serotypes

80
Q

Bluetongue Virus distribution

A

Worldwide distribution in tropical and subtropical countries

BTV serotype 8 just established itself in Northern Europe, and new serotype have spread throughout the Mediterranean basin recently

81
Q

Susceptible species to Bluetongue Virus

A

Ruminants, both domestic and wild

Significant disease only occurs in sheep and white tail deer (mostly sheep). Cattle generally undergo subclinical infections but serve as a reservoir and amplifying host for BTV

82
Q

What species is of most significance in Bluetongue Virus?

A

SHEEP

Most economically relevant, and most significant disease

Cattle are subclinically infected with BTV and serve as amplifying host/reservoir hosts

83
Q

What does clinical disease with BTV depend on?

A

Environment (vector population)
animal species present
Serotype of BTV involved

84
Q

Where in the US is BTV?

A

High prevalence in south and west US, but low in Northern US

85
Q

When do outbreaks of BTV occur?

A

Summer and fall, when the insect vector (Culicoides) is active

86
Q

Transmission of BTV?

A

Natural transmission is via Vulivoides (in US, Vulivoides variipennis). This requires extrinsic incubation period of 8-10 days for viral transmission

Some virus serotypes will cross the placenta in viremic pregnant ewes and cattle

Virus can be transmitted via semen during AI/natural service. However, bulls will excrete the virus in their semen only when they are viremic

87
Q

Clinical signs of BTV in sheep

A

In sheep, high fever, then nasal discharge and excessive salivation

  • reddening of nasal and buccal mucosa followed by excoriation of buccal mucosa
  • tongue and gums are very swollen, tongue may turn purple/blue
  • diarrhea and lameness often seen
  • a wee or two after fever (first sign), may se torticollis (wryneck)
  • complete loss of fleece may occur weeks after infection in those animals that recover
  • VERY LONG CONVALESCENT PERIOD
88
Q

Fetal infections with BTV

A

Occur in sheep and cattle, but only with some serotypes (serotype 8 is notable for ability to cross placenta)
-fetal malformation most often associated with BTV is HYDRANCEPHALY OF THE CEREbRAL HEMISPHERES and ARTHROGRYPOSIS

89
Q

Cattle infections with BTV

A

Most infections in cattle with BTV are inapparent***
-lesions similar to those seen in sheep can be seen (fever, lameness in all 4 limbs due to laminates, edema of lips, erosive lesions in mouth, nasal discharge, and excessive salivation)

  • skin of bares may peel
  • BTV DOES NOT CAUSE DIARRHEA IN CATTLE

-infection in early pregnancy can lead to calves being born with hydranencephaly and arthrogryposis

90
Q

Pathogenesis of BTV

A

Infects and replicates in macrophages, dendritic cells, and vascular endothelium

Virus mediated vascular injury leads to thrombosis of the small arteries resulting in infarct

Widespread petechial hemorrhage and necrosis in most organs with extensive edema

BTV released in blood binds to RBC that are long lived, resulting in viremia

91
Q

Pathological lesions of BTV

A

BTV CAUSES ARTERITIS**

Virus mediated vascular injury results in thrombosis and tissue infarction–> widespread hemorrhage and edema in most tissues

Mucosal lesions (erosions, ulceration, hemorrhages, and edema) are seen in the mouth, esophagus, and forestomach

The lungs in sheep are heavy with frothy fluid in the air passages

Hemorrhagic lesion at the base of the pulmonary artery*** almost pathognomonic

92
Q

Diagnosis of BTV

A

Virus isolation (virus labile to freezing temperatures, so store blood and samples at 4*C)

Virus ID via RT-PCR

Serology- Ab detected by immunodiffusion, serotype determined by VNT… paired samples (acute and convalescent)

93
Q

Prevention and Control of BTV

A

MLV vaccine (but notorious for its ability to cross placenta and infect developing fetus)

DO NOT vaccinate ewes during pregnancy… can result in stillbirths and fetal malformation

94
Q

Epizootic Hemorrhagic Disease (EHD) general characteristics

A

Very similar to Bluetongue virus but it does not affect sheep

Cattle and DEER are susceptible to infection

95
Q

Epizootic hemorrhagic disease susceptible species

A

Most importantly, deer
Also cattle

NOT SHEEP

96
Q

EHDV family

A

Family orbivirus

Shared internal antigens with BTV

97
Q

EHDV. Shares internal antigens with BTV?

A

yes

98
Q

Serotype of EHDV

A

10 serotypes of EHDV are known

EHDV-1 and EHDV-2 are the 2 most important types in the US

Geographic occurrence of EHD is similar to Bluetongue (south and west US)

99
Q

Transmission of EHDV

A

culicoides variipennis, seen seasonally in latesummer and fall

100
Q

EHDV is _____ morbidity and ____ mortality in ____ animal

A

HIGH morbidity, HIGH mortality in white tail deer only

One of the most important diseases of deer in the US

101
Q

EHDV in white tail deer

A

In WTD, characterized by acute hemorrhagic disease (high mortality)

causes an acute infection and most affected animals are found dead by hunters

102
Q

Clinical signs of EHDV

A

Acute hemorrhagic disease in WTD, with most affected animals found dead by hunters

Clinical signs resembles Bluetongue (lung edema, widespread hemorrhages

103
Q

EHDV in cattle

A

seroprevalence shows it is common in cattle but clinical disease is very rare

EHDV can cause lameness and mouth lesions that resemble vesicular diseases

104
Q

Pathogenesis of EHDV

A

Infects endothelial cells of blood vessels, causing an arteritis

105
Q

Diagnosis of EHDV

A

Similar as BTV- EHDV antibodies cross react with BTV

PCR

Serology to detect presence of AB (AGID, ELISA)

106
Q

Ibaraki disease

A

Virus related antigenically to EHDV. Disease similar to EHDV/BTV

virology (5 decks)

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