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14
Forage & Nutrition
Guide 2018
Leptospirosis: a risk to your herd
and your health
Leptospirosis is one of the most common causes of abortion in cattle in
Ireland. It is an endemic disease, meaning that the majority of herds test
positive for it
Leptospirosis is also a zoonosis, which means it can cause
disease in humans. All those working with stock are potentially
at risk. Clinical signs of the disease in humans are flu-like, with
headaches and fever, occasionally progressing to meningitis.
Leptospirosis As a zoonotic disease, leptospirosis can be
acquired from contact with urine, afterbirth or aborted foetus
of an infected animal. There are two serovars of leptospirosis
commonly found in cattle in Ireland:
Leptospira interrogans Hardjo; and
Leptospira borgpetersenii Hardjo.
Leptospirosis circulates in a herd by direct transmission
from infected animals (new infections or carrier animals)
or by indirect transmission through urine, birth fluids, milk,
contaminated water or other species, eg. sheep. Leptospirosis
is very difficult to eradicate as some cows can become carriers.
Leptospires can also survive for up to six weeks in wet soil and
stagnant water or slow-moving streams.
CLINICAL SIGNS OF LEPTOSPIROSIS
Early signs are usually mild and transient and, therefore, may
go unnoticed. The most common clinical signs include:
Milk drop a sudden decrease in milk yield;
Abortions usually occur six to 12 weeks after the initial
infection;
Abortion rates may be up to 30 per cent in a herd infected
for the first time;
Infertility low pregnancy rates and increased culling due
to low fertility; and
Weak calves infection in late pregnancy can result in the
birth of weak calves that die within a few hours of birth.
DIAGNOSIS OF LEPTOSPIROSIS
Based on:
Blood sampling and looking for high antibody levels in
affected animals (which can prove difficult as often the
infection is present six to 12 weeks before clinical signs
become apparent, eg. low pregnancy rates picked up at
scanning;
Culture of urine samples; and
Leptospiral abortion diagnosis is best based on finding
bacteria in the foetus.
Speak to your vet about investigating leptospirosis in your
herd.
CONTROL OF LEPTOSPIROSIS
Based on:
Isolation of the sick cow and aborting cow;
Biosecurity avoid the introduction of infected animals;
Quarantine until tests return negative;
Double fencing at perimeters; and
Vaccination the only practical way of controlling
leptospirosis.
TIMING OF VACCINATION
It is essential to vaccinate heifers before their first pregnancy.
The primary vaccination course consists of two injections
of Leptavoid-H four to six weeks apart and, thereafter, an
annual booster before turnout and at least two weeks before
breeding. It is a 2ml dose, given under the skin to all cattle
greater than one month of age. The correct use and timing
of vaccination are vital to their success, always read the
manufacturers recommendations.
WHY VACCINATE WITH LEPTAVOID-H?
Leptavoid-H is the only vaccine licensed to protect
against both strains of Leptospira Hardjo;
Leptavoid-H is the only vaccine that is licensed to
improve conception rates where leptospirosis has been
diagnosed as a cause of infertility; and
Leptavoid-H can be used on the same day as Bovilis BVD
(to cattle greater than eight months of age).
Author: Cara Sheridan
Ruminant vet adviser, MSD Animal Health
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