Small ruminants 2/2 Flashcards
Contagious agalactia is a contagious disease of sheep and goats, caused mainly by Mycoplasma agalactiae, and is characterized by (3)
mastitis, polyarthritis and keratoconjunctivitis.
Causative agent of contagious agalactia.
gram status
Mycoplasma agalactiae
But also other mycoplasma spp.:
M. capricolum subsp. capricolum
M. putrefaciens
M. mycoides subsp. capri
M. mycoides subsp. mycoides large colony (LC)
Gram neg. of course
Survival of mycoplasma.
Relatively fragile in the environment.
Can produce biofilm – protects from heat and drying, enhance the survival.
Host range of contagious agalactia.
sheep and goats
M. agalactiae - both species
M. capricolum subsp. capricolum &
M. mycoides subsp. capri &
M. mycoides subsp. mycoides large colony (LC): Mainly goats, rarely sheep
M. putrefaciens – only goats
Transmission of contagious agalactia.
Excretion: all bodily fluids basically.
Direct contact
Indirect contact (feed, water)
Fomites
Aerosols
Route: alimentary, respiratory, through teat openings.
IP of contagious agalactia.
1-8 weeks
Clinical signs of contagious agalactia with M.agalactiae.
Clinical signs more severe in goats than in sheep.
Acute:
Transient fever, malaise, inappetence and mastitis & Agalactia.
Udder can atrophy and fibrose too.
Polyarthritis, keratoconjunctivitis poss. too.
Abortions in chronic cases
Contagious agalactia can be what forms/courses?
Asymptomatic, acute, chronic.
And what 3 main conditions can the acute form of disease caused by M.agalactiae produce?
mastitis
polyarthritis
keratoconjunctivitis
Clinical signs of Mycoplasma spp. other than M.agalactiae - in GOATS.
M. mycoides mycoides LC, M. mycoides capri, M. capricolum capricolum, M. putrefaciens:
Mainly in goats
Acute or hyperacute
Pneumonia and/or septicemia with fever, prostration, anorexia, generalized malaise.
Mortality is high, Sudden deaths
Mastitis, arthritis, keratoconjunctivitis (tho No ocular signs with M. putrefaciens).
Abortion
Genital lesions
Clinical signs of Mycoplasma spp. other than M.agalactiae - in SHEEP.
M. mycoides mycoides LC: vulvovaginitis, balanoposthitis (glans & prepuce inflamm.)
M. capricolum capricolum: genital lesions
Post mortem signs of contagious agalactia.
Signs of septicemia, pneumonia, mastitis, arthritis and/or keratoconjunctivitis.
Some cases: genital lesions such as vulvovaginitis, cystic catarrhal metritis and/or salpingitis; balanoposthitis or testicular degeneration.
Suspect contagious agalactia when
keratoconjunctivitis and arthritis presents in a herd with mastitis and decreased milk production, particularly when these signs develop near the time of parturition.
Material for diagnosis of contagious agalactia.
Nasal, conjunctival swabs
Joint fluid aspiration
Milk
Blood
Tissue samples – udder (and associated LNs), lung
Lab analyses for diagnosis of contagious agalactia.
Isolation of the organism – culture
Identifying the agent – PCR
Serology (complement fixation, ELISA) – for herd testing
Tx of contagious agalactia.
Tx: ABs
Results in symptomatic improvement; not so effective in chronic joint infections or keratoconjunctivitis.
May not eliminate the carriers!
Prevention & control of contagious agalactia.
good management and hygiene
Isolation of the sick
Milking animals should be separated from the young
Regular testing + culling/isolation of the sick
Vaccination (prevents symptoms but not infection)
Ovine pulmonary adenocarcinoma is a contagious disease of sheep, caused by retrovirus, and is characterized by
pulmonary neoplasia.
Causative agent for Ovine pulmonary adenocarcinoma.
genus
family
DNA type
Jaagsiekte sheep retrovirus (JSRV)
Also known as: pulmonary adenomatosis virus.
Genus Betaretrovirus,
family Retroviridae
RNA virus
What is Jaagsiekte sheep retrovirus (JSRV) also known as:
pulmonary adenomatosis virus
Survival of JSRV.
Jaagsiekte sheep retrovirus (JSRV)
Does not survive for long in the environment.
Susceptible to most common disinfectants.
Host range of Ovine pulmonary adenocarcinoma.
domesticated sheep
Most cases in sheep >2 years of age
(peaks: 3-4 years)
Morbidity & mortality of Ovine pulmonary adenocarcinoma.
Recently infected herds: high, <80% mortality
Longer presence: 2-5% (<20%) mortality
Incidence rate much higher than morbidity – most sheep do not develop tumors during their commercial lifespan.
Transmission of Ovine pulmonary adenocarcinoma.
Excretion: respiratory exudates. Also maybe milk.
Direct contact – aerosols, droplets
Route: respiratory
Virus can be found in tumors, lung fluids, peripheral blood leukocytes and lymphoid organs.
Before tumor development: virus is detected in lymphoreticular cells.
IP of Ovine pulmonary adenocarcinoma.
IP: 6 months to 3 years
Age-dependent – longer in older sheep.
Clinical signs of Ovine pulmonary adenocarcinoma.
Clinical signs occur ONLY in animals that have developed tumors.
Progressive emaciation, weight loss, respiratory compromise.
Thick mucus discharge from nostrils; copious frothy exudate if head is lowered.
Moist audible rales on auscultation.
Signs are slowly progressive toward severe dyspnea.
Death in days to few months, often due secondary bacterial pneumonia.
Post mortem signs of Ovine pulmonary adenocarcinoma.
Lungs are enlarged.
In advanced cases: they do not collapse upon opening the chest cavity.
Frothy fluid in trachea and bronchi
Tumors in lungs
Apical, cardiac and ventral portions of the diaphragmatic notches.
Vary from small nodules to solid masses.
Clearly demarcated, firm, gray or pinkish-gray.
On cut surfaces: glistening and granular, frothy fluid expressed.
Often secondary pneumonia and fibrinous pleuritis.
Tumor metastasis only to nearby LNs.
Suspect Ovine pulmonary adenocarcinoma when
chronic respiratory signs, particularly in 2-4-year-old animals with frothy mucoid discharge from the nostrils.
What positional test can you do on live sheep to diagnose ovine pulmonary adenocarcinoma?
“Wheelbarrow test” – to check for excess fluid in the lungs
Material for diagnosis of ovine pulmonary adenocarcinoma
Tumor (lung and regional LNs)
Lung fluid
Blood (peripheral)
Colostrum, milk
Lab analyses for diagnosis of ovine pulmonary adenocarcinoma
Histopathology
Detecting viral antigens
Detecting viral RNA – PCR
No culture and no serology!
Absence of an immunological response.
Tx of ovine pulmonary adenocarcinoma.
No Tx
No vaccine
Prevention & control of ovine pulmonary adenocarcinoma.
Replacement from flocks with no dz history.
To reduce losses: remove affected sheep and the offspring of infected ewes.
Does not eradicate the dz from flock!
Good disinfection and general hygiene.
