Leptospirosis - created from Mind Map

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Aetiology

aquatic spirochetes

hardjo serovar in UK

L. pomona or L. icterohermorrhagica

Public health risk

Pathogenesis

Leptospira borgpetersenii - Hardjo

Leptospira interrogans - Hardjo

serologically indistinguishable

severe disease

considerably less common

flu like symptoms

penetration of MM

transmission

penetration of skin barrier

bacteremia for 6-9 days

humoral antibodies

hematogenous spread

renal shedding in 14 days

persistent for months

contact with contaminated urine

abortive products

venerial from bulls

hardjo NOT carried by wildlife

sheep carriers, not clinical

pasture can remain infectious for 2 months

Risk Factors

open herd

shared bulls

mixed grazing with sheep

shared grazing/water courses

between herds or with sheep

Clinical Signs

Milk drop

generally none in endemic herds

Abortion

Infertillity

sudden drop or stop

thick colostrums or blood tinge

lethargy and pyrexia

''flabby bag''

3-12 weeks post infection

last trimester

weak or premature calves

significant economic loss

circumstantially indicated

improved by vaccine vs endemic immunity

Diagnosis

Milk Drop

Abortion

Herd screening

paired serology @3-4 weeks

antibiotics interfere

leptospires in urine

seroconversion

microscopy

PCR

maternal serology USELESS

aborted fetus

antibodies in fetal fluid

fluorescent antibody test

test 25%

some +ve = probably outbreak in past

many +ve = outbreak recently

high titres = active invection

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Treatment

Streptomycin

oxytetracycline/amoxycillin

single i/m dose works for most cases

prevents carriers

may allow some to remain carriers

Prevention

managment

adjuvanted vaccines

closed herd

during acute infeciton

endemic infection

avoid mixing with sheep

avoid shared water courses

whole herd antibiotics

vaccine program

vaccinate heifers before entering herd

complete heifer vaccination before breeding

vaccines economical?

annual boosters to protect herdsmen

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

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

shared grazing/water source with sheep may cause infection

may be carried by sheep but NOT wildlife

control of substances hazardous to health (COSHH) regulations

oral, GIT, repro

water damage

must be performed ASAP because Bacteria decompose quickly

Leptospirosis

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