Inf. diseases II - Ruminant diarrhea & repro. 2/2 Flashcards
Bovine genital campylobacteriosis is an infectious disease of cattle, caused by Campylobacter fetus, and characterized by
infertility, early embryonic death and prolonged calving season.
Causative agent of Bovine genital campylobacteriosis.
gram?
gram neg. bacterium Campylobacter fetus
Two subspecies that cause BGC:
Campylobacter fetus subsp. venerealis
Campylobacter fetus subsp. fetus
Survival of Campylobacter spp.
Campylobacter spp. do not tolerate drying or heating.
Can survive for weeks in water at 4°C
But only few days in water >15°C
C. fetus can survive in liquid manure for 24 hours and soil for up to 20 days
Host range of Bovine genital campylobacteriosis
Host range: cattle and other ruminants
Campylobacter fetus subsp. venerealis – cattle
Campylobacter fetus subsp. fetus – cattle, sheep and goats.
Opportunistic in humans
Transmission of bovine genital campylobacteriosis.
Excretion: feces, vaginal discharges, aborted fetuses, fetal membranes, semen
Venereal transmission
Direct contact
Ingestion
Fomites
Route: oral or genital
Clinical signs of campylobacter reproductive disease.
Infertility
Early embryonic death
Abortions uncommon
May develop mucopurulent endometritis, no other systemic signs
Bulls are asymptomatic
Clinical signs of C. fetus subsp. fetus In sheep:
Late term abortions, stillbirths and weak lambs
Sometimes metritis, occasionally death
Clinical signs of C.fetus in humans.
C. fetus – opportunistic human pathogen
Causes mainly systemic infections:
Mild intestinal symptoms
Fever – may be the only consistent signs
IP of campylobacteriosis
IP: 3-5 days
Post mortem signs of Campylobacter fetus
In aborted cattle fetuses:
Bronchopneumonia
Mild fibrinous pericarditis
Peritonitis
Mild placentitis – cotyledons may be hemorrhagic and the intercotyledonary area edematous.
In sheep: fetus is usually autolyzed
Material for diagnosis of Campylobacter fetus: (3)
Cervical mucus (swab)
Semen
Aborted fetuses and placenta
Lab analyses for diagnosis of Campylobacter fetus: (3)
Culture
Serology – specific IgA
RT-PCR
Tx of Campylobacter fetus
ABs for bulls
Cows are usually not treated
Streptomycin (locally)
Prevention & control of Campylobacter fetus
Good hygiene to reduce transmission
Avoidance of stress to decrease shedding in carriers
Vaccination – not in Estonia!
Using artificial insemination instead of natural mating
Bovine tuberculosis is a chronic bacterial disease of cattle, caused by Mycobacterium bovis, and characterized by
respiratory illness and formation of tubercles.
Causative agent of bovine tuberculosis.
gram?
Mycobacterium bovis
Gram+, acid-fast
Belongs to the Mycobacterium tuberculosis complex
Mycobacterium tuberculosis complex includes: (7)
M. tuberculosis
M. africanum
M. canettii
M. caprae
M. bovis
M. pinnipedii
M. microti
Survival on Mycobacterium bovis in environment:
Persists in the environment for months in cold, dark and moist conditions.
Survives in natural pastures for a few weeks.
Relatively resistant to disinfectants, requires long contact times for inactivation.
E.g. formaldehyde
Host range of M. bovis
mammals
Primary host: cattle
Maintenance hosts: brush-tailed opossums, badgers, bison and elk, kudu and African buffalo.
Zoonotic!
Morbidity and mortality of M.bovis
Morbidity:
In developed countries: rare
In studies:
0-40% infected and 0-10% developed gross lesions
Transmission of M.bovis in cattle.
Excretion: respiratory secretions, feces and milk. Sometimes in the urine, vaginal secretions or semen.
Large numbers of organisms may be shed in the late stages of infection.
Direct contact
Aerosols
Route: respiratory, ingestion (calves)
Cutaneous, genital and congenital are rare
IP: of M.bovis
IP: months
Can remain dormant for years and reactivate during periods of stress or in old age.
Clinical signs of early bovine tuberculosis.
Early stages can be asymptomatic.
Clinical signs of late stage bovine tuberculosis.
Late stage:
Progressive emaciation
Fever, weakness, inappetence
Moist cough
Enlarged, draining lymph nodes
Clinical signs of terminal stage bovine tuberculosis.
Terminal stage:
Extreme emaciation
Acute respiratory distress
Post mortem signs of bovine tuberculosis.
Granulomas (tubercles):
Yellowish and caseous, caso-calcareous or calcified
Often encapsulated
In LNs – particularly in head and thorax
In other organs – lung, spleen, liver and the surfaces of body cavities
Diagnosis of M.bovis in live cattle:
tuberculin skin test
Intradermal injection, positive: delayed hypersensitivity reaction (swelling).
Sometimes false negatives are seen.
Material for diagnosis of M.bovis. (3)
Blood
Abnormal LNs
Affected organs – lungs, liver and spleen
Lab analyses for diagnosis of M.bovis.
Histopathology/microscopic exam
Culture, biochemical tests
PCR
Additionally to the tuberculin test:
Lymphocyte proliferation test
Gamma-interferon test
ELISA
Tx of M.bovis
No tx!
Prevention & control of M.bovis:
Test-and-slaughter or test-and-segregation methods: Test-and-slaughter to eradicate!!!
Slaughter surveillance
Sanitation and disinfection in herds
Rodent control
M.bovis in people
Occupational hazard for people working with cattle (e.g. farmers, abattoir workers).
Higher incidence rate in countries with uncontrolled bovine TB.
Transmission: ingestion of unpasteurized dairy products; aerosols, abraded skin, raw undercooked meat.
Clinical signs:
Asymptomatic
Localized lymphadenopathy
Skin dz (“butcher’s wart”)
Pulmonary dz
Tx: ABs – can be fatal if not treated!
