Zusammenfassung der Ressource
Leptospirosis
- Aetiology
- aquatic spirochetes
- hardjo serovar in UK
- Leptospira borgpetersenii - Hardjo
- Leptospira interrogans - Hardjo
- serologically indistinguishable
- L. pomona or L. icterohermorrhagica
- severe disease
- considerably less common
- Public health risk
- flu like symptoms
- Pathogenesis
- penetration of MM
Anmerkungen:
- penetration of skin barrier
Anmerkungen:
- bacteremia for 6-9 days
- humoral antibodies
- hematogenous spread
- renal shedding in 14 days
- persistent for months
- transmission
- contact with contaminated urine
- pasture can remain infectious
for 2 months
- abortive products
- venerial from bulls
- hardjo NOT carried by wildlife
- sheep carriers, not clinical
- Risk Factors
- open herd
- shared bulls
- mixed grazing with sheep
- shared grazing/water courses
- between herds or with sheep
- Clinical Signs
- Milk drop
- sudden drop or stop
- ''flabby bag''
- thick colostrums or blood tinge
- lethargy and pyrexia
- generally none in endemic herds
- Abortion
- 3-12 weeks post infection
- last trimester
- significant economic loss
- weak or premature calves
- Infertillity
- circumstantially indicated
- improved by vaccine vs endemic immunity
- Diagnosis
- Milk Drop
- paired serology @3-4 weeks
- seroconversion
- antibiotics interfere
- leptospires in urine
- microscopy
- PCR
- Abortion
- maternal serology USELESS
- aborted fetus
- antibodies in fetal fluid
- fluorescent antibody test
Anmerkungen:
- must be performed ASAP because Bacteria decompose quickly
- Herd screening
- test 25%
- some +ve = probably outbreak in past
- many +ve = outbreak recently
- high titres = active invection
- Enter text here
- Treatment
- Streptomycin
- single i/m dose works for most cases
- prevents carriers
- oxytetracycline/amoxycillin
- may allow some to remain carriers
- Prevention
- managment
- closed herd
- avoid mixing with sheep
- avoid shared water courses
- during acute infeciton
- whole herd antibiotics
- vaccine program
- vaccinate heifers
before entering herd
- endemic infection
- complete heifer vaccination
before breeding
- vaccines economical?
- annual boosters to
protect herdsmen
- adjuvanted vaccines
- 2 @ 4 weeks
- ELISA to check titres
- prevents urine shedding
- protects against milk drop and abortion
- key points
- blood tests cannot
determine state of infection
- serology can diagnose
acute infection
- most common source is bought
on or borrowed animals
- shared grazing/water source with
sheep may cause infection
- may be carried by sheep but NOT wildlife
- clinical disease may only be apparent
as acute infection enters the herd
- vaccines prevent clinical signs and
reduce shedding, do not eradicate
- herdsmen must be protected from infection
- control of substances hazardous
to health (COSHH) regulations