Inf. diseases II - Ruminant diarrhea & repro. 1/2 Flashcards by Laura Westman

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.

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Causative agent of Winter dysentery.
family
genus
dna type

Agent: Bovine coronavirus (BCoV)
Family Coronaviridae
Genus Coronavirus

RNA virus, single-stranded

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Survival of BCV in environment.

Bovine coronavirus

Survives best at low temperatures and at low UV light intensities

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Host range and age demographic of BCV

Bovine coronavirus

Affects mainly adults – most severely adult lactating cows that have recently calved

In humans: not

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Seasonality of Bovine coronavirus

More common during winter months and in Northern climates

Typical outbreak lasts for 1-2 weeks

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Morbidity of BCV.

Morbidity – high in affected herds

20-50% within few days, close to 100% within a week

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Mortality of BCV.

Mortality – low: 1-2%

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Transmission of BCV

Excretion: feces, respiratory excretions

Ingestion
Indirect contact
Fomites

Route: fecal-oral

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IP: of BCV

IP: 3-7 days

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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

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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

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MAterial for diagnosis of BCV. (3)

Feces
Blood
Colon, cecum

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LAb analyses for BCV. (3)

Serology (ELISA)
RT-PCR
Histology

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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

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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.

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Rotavirus causes

viral diarrhea in calves, lambs and other animals.

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Rotavirus family and dna type.

Family Reoviridae
RNA virus

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Rotavirus Groups

A and B

A is most prevalent and clinically important

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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!

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Morbidity of rotavirus.

Morbidity – variable:
5-10% then up to 50-80% (3rd year)

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Mortality of rotavirus.

Mortality: 5-60%

Depends on colostral immunity etc.

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Transmission of rotavirus.

Excretion: feces
Direct contact
Route: fecal-oral

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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

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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