Inf. diseases II - Ruminant diarrhea & repro. 2/2

Question 1

Bovine genital campylobacteriosis is an infectious disease of cattle, caused by Campylobacter fetus, and characterized by

Answer 1

infertility, early embryonic death and prolonged calving season.

Question 2

Causative agent of Bovine genital campylobacteriosis.
gram?

Answer 2

gram neg. bacterium Campylobacter fetus

Two subspecies that cause BGC:
Campylobacter fetus subsp. venerealis
Campylobacter fetus subsp. fetus

Question 3

Survival of Campylobacter spp.

Answer 3

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

Question 4

Host range of Bovine genital campylobacteriosis

Answer 4

Host range: cattle and other ruminants

Campylobacter fetus subsp. venerealis – cattle
Campylobacter fetus subsp. fetus – cattle, sheep and goats.

Opportunistic in humans

Question 5

Transmission of bovine genital campylobacteriosis.

Answer 5

Excretion: feces, vaginal discharges, aborted fetuses, fetal membranes, semen

Venereal transmission
Direct contact
Ingestion
Fomites

Route: oral or genital

Question 6

Clinical signs of campylobacter reproductive disease.

Answer 6

Infertility
Early embryonic death
Abortions uncommon
May develop mucopurulent endometritis, no other systemic signs

Bulls are asymptomatic

Question 7

Clinical signs of C. fetus subsp. fetus In sheep:

Answer 7

Late term abortions, stillbirths and weak lambs

Sometimes metritis, occasionally death

Question 8

Clinical signs of C.fetus in humans.

Answer 8

C. fetus – opportunistic human pathogen

Causes mainly systemic infections:
Mild intestinal symptoms
Fever – may be the only consistent signs

Question 9

IP of campylobacteriosis

Answer 9

IP: 3-5 days

Question 10

Post mortem signs of Campylobacter fetus

Answer 10

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

Question 11

Material for diagnosis of Campylobacter fetus: (3)

Answer 11

Cervical mucus (swab)
Semen
Aborted fetuses and placenta

Question 12

Lab analyses for diagnosis of Campylobacter fetus: (3)

Answer 12

Culture
Serology – specific IgA
RT-PCR

Question 13

Tx of Campylobacter fetus

Answer 13

ABs for bulls

Cows are usually not treated
Streptomycin (locally)

Question 14

Prevention & control of Campylobacter fetus

Answer 14

Good hygiene to reduce transmission

Avoidance of stress to decrease shedding in carriers

Vaccination – not in Estonia!

Using artificial insemination instead of natural mating

Question 15

Bovine tuberculosis is a chronic bacterial disease of cattle, caused by Mycobacterium bovis, and characterized by

Answer 15

respiratory illness and formation of tubercles.

Question 16

Causative agent of bovine tuberculosis.
gram?

Answer 16

Mycobacterium bovis
Gram+, acid-fast

Belongs to the Mycobacterium tuberculosis complex

Question 17

Mycobacterium tuberculosis complex includes: (7)

Answer 17

M. tuberculosis
M. africanum

M. canettii
M. caprae

M. bovis
M. pinnipedii
M. microti

Question 18

Survival on Mycobacterium bovis in environment:

Answer 18

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

Question 19

Host range of M. bovis

Answer 19

mammals
Primary host: cattle

Maintenance hosts: brush-tailed opossums, badgers, bison and elk, kudu and African buffalo.

Zoonotic!

Question 20

Morbidity and mortality of M.bovis

Answer 20

Morbidity:
In developed countries: rare

In studies:
0-40% infected and 0-10% developed gross lesions

Question 21

Transmission of M.bovis in cattle.

Answer 21

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

Question 22

IP: of M.bovis

Answer 22

IP: months

Can remain dormant for years and reactivate during periods of stress or in old age.

Question 23

Clinical signs of early bovine tuberculosis.

Answer 23

Early stages can be asymptomatic.

Question 24

Clinical signs of late stage bovine tuberculosis.

Answer 24

Late stage:
Progressive emaciation
Fever, weakness, inappetence
Moist cough
Enlarged, draining lymph nodes

Question 25

Clinical signs of terminal stage bovine tuberculosis.

Answer 25

Terminal stage:
Extreme emaciation
Acute respiratory distress

Question 26

Post mortem signs of bovine tuberculosis.

Answer 26

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

Question 27

Diagnosis of M.bovis in live cattle:

Answer 27

tuberculin skin test

Intradermal injection, positive: delayed hypersensitivity reaction (swelling).

Sometimes false negatives are seen.

Question 28

Material for diagnosis of M.bovis. (3)

Answer 28

Blood
Abnormal LNs
Affected organs – lungs, liver and spleen

Question 29

Lab analyses for diagnosis of M.bovis.

Answer 29

Histopathology/microscopic exam
Culture, biochemical tests
PCR

Additionally to the tuberculin test:
Lymphocyte proliferation test
Gamma-interferon test
ELISA

Question 30

Tx of M.bovis

Answer 30

No tx!

Question 31

Prevention & control of M.bovis:

Answer 31

Test-and-slaughter or test-and-segregation methods: Test-and-slaughter to eradicate!!!

Slaughter surveillance

Sanitation and disinfection in herds

Rodent control

Question 32

M.bovis in people

Answer 32

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!