Inf. diseases II - Ruminant diarrhea & repro. 1/2 Flashcards
Winter dysentery is a highly contagious disease of adult cattle, caused by Coronavirus, and characterized by
an acute onset of a short course of severe diarrhea and sometimes dysentery.
Causative agent of Winter dysentery.
family
genus
dna type
Agent: Bovine coronavirus (BCoV)
Family Coronaviridae
Genus Coronavirus
RNA virus, single-stranded
Survival of BCV in environment.
Bovine coronavirus
Survives best at low temperatures and at low UV light intensities
Host range and age demographic of BCV
Bovine coronavirus
Affects mainly adults – most severely adult lactating cows that have recently calved
In humans: not
Seasonality of Bovine coronavirus
More common during winter months and in Northern climates
Typical outbreak lasts for 1-2 weeks
Morbidity of BCV.
Morbidity – high in affected herds
20-50% within few days, close to 100% within a week
Mortality of BCV.
Mortality – low: 1-2%
Transmission of BCV
Excretion: feces, respiratory excretions
Ingestion
Indirect contact
Fomites
Route: fecal-oral
IP: of BCV
IP: 3-7 days
Clinical signs of Winter dysentery
Acute onset of fluid diarrhea (Liquid and homogenous feces with little odor, green to black; May contain blood or mucus)
Profound decrease in milk production (25-95% production loss).
Mild colic
Dehydration
Depression
Brief period of anorexia
Some decrease in body condition
Post mortem signs of Winter dysentery
Lesions in large intestines:
Cecal and colonic mucosal hyperemia
Linear streaks or pinpoint-sized hemorrhages mostly along the colonic mucosal ridges
Blood in the lumen
Small intestine may be dilated and flaccid
MAterial for diagnosis of BCV. (3)
Feces
Blood
Colon, cecum
LAb analyses for BCV. (3)
Serology (ELISA)
RT-PCR
Histology
Tx of BCV
control of it?
Tx: no specific Tx since the course of dz is short
Fluids, electrolytes
Control dz with Biosecurity, good hygiene
Calf diarrhea caused by bovine corona virus
1 day to 3 month-olds
(most often 1-2 week-olds)
Virus is widespread
More common during winter months
Transmission route: alimentary or respiratory
Excretion: feces, respiratory secretions and tears
Source of transmission can be adult cows!
Diarrhea and dehydration
Sometimes respiratory illness (mostly mild)
Prevention: colostrum (antibodies)!
Calves not fed with colostrum right after birth have more severe illness.
Rotavirus causes
viral diarrhea in calves, lambs and other animals.
Rotavirus family and dna type.
Family Reoviridae
RNA virus
Rotavirus Groups
A and B
A is most prevalent and clinically important
Host range of rotavirus
Age demographic?
Host range in animals: cattle, buffalo calves, lambs, foals, kids, pet animals
Espesh: Calves 1-3 weeks of age
Groups A to both humans and animals.
Zoonosis!
Morbidity of rotavirus.
Morbidity – variable:
5-10% then up to 50-80% (3rd year)
Mortality of rotavirus.
Mortality: 5-60%
Depends on colostral immunity etc.
Transmission of rotavirus.
Excretion: feces
Direct contact
Route: fecal-oral
Clinical signs of rotavirus.
Moderate depression
Dehydration
Often continue to suckle or drink milk
Diarrhea
Feces are voluminous, soft to liquid, often contain large amounts of mucus
Commonly persist 3 or more days
Post mortem signs of rotavirus.
No characteristic lesions!
Material for diagnosis of rotavirus.
Feces
Tissue samples from intestines
LAb analyses for diagnosis of rotavirus.
Direct immunofluorescence
ELISA
Tx of rotavirus.
no specific Tx
Prevention & control of rotavirus.
Biosecurity
Hygiene
Good animal husbandry
Adenoviral pneumoenteritis of calves is a contagious disease of calves, caused by Adenovirus, and is characterized by
catarrhal hemorrhagic enteritis.
Causative agent of BAV.
genus
family
dna type
bovine adenovirus or adenoviral pneumoenteritis of calves
Genus Mastadenovirus,
family Adenoviridae
double-stranded DNA
serotypes of bovine adenovirus
10 serotypes
Adenoviruses have oncogenic properties
Adenovirus survival in environment
Survival at room temperature for 1-4 months
Host range and age demo. of adenoviral pneumoenteritis of calves.
cattle
4 week to 4 month-olds calves are susceptible and Older calves get subacute or chronic dz.
Recovered calves stay weak, have persistent cough.
In adults: enteritis
Morbidity and mortality of adenoviral pneumoenteritis of calves.
On primary introduction spreads quickly within herd. Morbidity not given.
Mortality <60%
Transmission of adenoviral pneumoenteritis of calves.
Excretion: nasal discharge, feces
Fomites (contaminated feed, water, bedding)
Route: respiratory or alimentary
IP: of adenoviral pneumoenteritis of calves
IP: 4-7 days
Clinical signs of adenoviral pneumoenteritis of calves
High fever, Inappetence, lethargy
Conjunctivitis – mucopurulent
Rhinitis
Cough and lacrimation
Some calves have also:
Diarrhea
Tympanites
Colic
Post mortem signs of adenoviral pneumoenteritis of calves.
Catarrhal or hemorrhagic inflammation in respiratory tract
Ulcerations and haemorrhage in the intestinal tract
In chronic form: pneumonia
MAterial for diagnosis of adenoviral pneumoenteritis of calves.
Nasal discharge
Ocular discharge
LNs
Lungs
Lab analyses for diagnosis of adenoviral pneumoenteritis of calves.
Virus isolation
Serology (ELISA)
PCR
Prevention & control of adenoviral pneumoenteritis of calves.
No Tx
No vaccine
Good biosecurity and animal husbandry.
Brucellosis is a contagious disease of cattle, caused mostly by Brucella abortus, and is characterized by
abortions and stillbirths.
Causative agent of Brucellosis in cattle.
gram?
Brucella abortus,
but Sometimes also B. melitensis or B. suis.
Gram neg.
brucellosis biovars
Nine biovars: 1-9
Survival of brucellosis.
Can remain viable for months in water, aborted fetuses, manure, wool, hay, equipment and clothes.
Need high humidity, low temperatures, no sunlight.
Can withstand drying especially when organic material is present.
Survives very short periods in meat
Exception: in frozen meat survives years
Killed by most commonly available disinfectants.
Host range of brucellosis.
Host range: ruminants – especially cattle, dogs, horses
Some genetic resistance has been reported
Zoonosis!
Morbidity of brucellosis.
Abortion rate 30-80% (unexposed & unvaccinated) – abortion storms are common.
Endemic herds: sporadic dz, cows may abort their first pregnancies.
Mortality of brucellosis
Mortality – deaths are rare amongst adults
Transmission of brucellosis
Excretion: placenta, fetus, fetal fluids, vaginal discharges, milk, urine, semen, feces and fetal fluids.
Many infected cattle become chronic carriers
Direct contact
In utero transmission
Fomites
Route: by ingestion, mucous membranes, broken skin
IP: of brucellosis
IP: 2 weeks to five months
Longer when infected early in gestation.
Clinical signs of brucellosis in cattle.
Abortions (usually during second half of gestation) and stillbirths.
Weak neonates that may die soon
Bulls: epididymitis, seminal vesiculitis, orchitis, testicular abscesses
Infertility
Hygromas
Infections in non-pregnant females usually asymptomatic!
Clinical signs of brucellosis in dogs.
DOGS:
abortions, epididymitis,
polyarthritis and other symptoms
May also be asymptomatic
Clinical signs of brucellosis in horses.
HORSES:
Inflammation of bursae:
Supraspinous (fistulous withers)
Supra-atlantal bursa (poll evil)
Abortions rare in horses
Post mortem signs of brucellosis.
Granulomatous inflammatory lesions in:
Reproductive tract
Udder
LNs
Joints
Abnormal placenta
Enlarged liver
Bulls: swollen scrotum
MAterial for diagnosis of brucellosis.
Milk sample
Vaginal swabs
Aborted fetuses or placenta
Spleen, LNs, udder, uterus
Semen
Testis, epididymis
Lab analyses for diagnosis of brucellosis.
Brucellin allergic skin test – unvaccinated animals.
Culture – to confirm diagnosis
Serology (ELISA)
PCR
Tx of brucellosis
no tx
Prvention and control of brucellosis
New animals from seronegative herds
Isolation of new animals for a month then retested.
Selective breeding for disease-resistant genotypes.
Eradication of brucellosis
Quarantine of infected herds.
Vaccination – not in Estonia!
Test-and-slaughter techniques
In herd: test-and-slaughter or depopulation
