148. Diseases of cattle and sheep caused by Histophilus somni. Flashcards
1
Q
Occurence, ethiology and epidemiology?
A
OCCURRENCE, ETIOLOGY AND EPIDEMIOLOGY
- Worldwide, sporadic occurrence
- Caused by H. somni (H. somnus, H. agni, H. ovis)
- 11 serotypes, present on mucous membranes
- Low resistance, Epiphyte, facultative pathogen
- Predisposing factors
- Non infectious:
- shipping,
- cold,
- overcrowding,
- nutrition,
- quality of air
- Infectious:
- adenovirus,
- IBR,
- PI-3,
- RS,
- mycoplasma
2
Q
Pathogenesis?
A
PATHOGENESIS
- Cattle: infection aerogenic or P.O. (sometimes via urine or semen)
- Predisposing factors
- replication in the respiratory tract
- septicemia
- Inflammation,
- thrombi, necrosis, vasculitis in CNS, respiratory airways, joints and fetus
- Sheep (cattle):
- infected semen,
- colonization of the mucous membranes
- ascending infection
3
Q
Clinical signs?
A
CLINICAL SIGNS
- Cattle
- Respiratory signs
- fever,
- nasal discharge,
- labored breathing
- Arthritis
- TEME: thromboembolic meningoencephalitis
- somnolence, spasms, ataxia, forced movements
- Abortion, endometritis, infertility, mastitis
- Sheep: young rams: orchitis and TRE epididymitis, rarely generalized signs
4
Q
Diagnosis and differentials ?
A
DIAGNOSIS
- Epidemiology, clinical signs and pathology
- Detection of the agent ʹ isolation and PCR
- Detection of antibodies ʹ ELISA
- Differentials
- Pneumonia
- pasteurellosis,
- mycoplasmosis,
- chlamydiosis,
- adenovirus, IBR,
- PI-3, RS
- CNS diseases
- listeriosis,
- chlamydiosis,
- rabies,
- IBR,
- leptospirosis
5
Q
Treatment and prevention?
A
TREATMENT AND PREVENTION
- Antibiotics for the pneumonic form, in USA
- feed lot prevention
- Prevention of predisposing factors
- Vaccines ʹ cattle: inactivated
- USA ʹ at arrival to the feed lot 2 times
- Pregnant cows 2 times, calves 2 times
