 INGELVAC® PRRS KV An inactivated, oil adjuvanted Porcine Reproductive and Respiratory
Syndrome (PRRS) virus vaccine containing at least 2.5 log10
Immuno Fluorescence units PRRS virus P120 strain per 2 ml dose.n
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In the 1980s a previously unrecognised disease syndrome
caused heavy production losses in pig herds in North
America.
Normal non infected porcine alveolar macrophage
(Electronic Microscope) In the following years this syndrome appeared
in many other major pig producing areas of North America and Europe.
In Europe a devastating epidemic, with estimates of
1 million or more pigs lost, occurred in the winter
of 1990/91. It has since spread worldwide, becoming
endemic in the major swine producing areas of the world.
The disease was formerly described by different names, such as
Pig plague 1989, Mystery Swine Disease (MSD), Abortus Blauw,
Blue Ear Pig Disease, or Porcine Epidemic and Abortion and
Respiratory Syndrome (PEARS). In April 1991 a meeting of European
Community veterinarians agreed on the name, Porcine Reproductive
and Respiratory Syndrom (PRRS), which was subsequently
adopted internationally.
The PRRSyndrome is caused by a virus which was identified in
Europe (the Netherlands) in 1991 by Wensvoort et al.The group
called it Lelystad virus after the town that contained their research
institute. In the USA Boehringer Ingelheim Animal Health Inc. isolated
the American
strain of the virus, recognised as ATCC VR-2332,
in a proprietary cell line from the lung of a gnotobiotic pig, infected
with field virus provided by the University of Minnesota. 
PRRS infected porcine
alveolar macrophage
Control of PRRS in UK pig herds has until now
consisted mainly of strict hygiene management
and class segregation. These measures have
provided only partial control and the recent
introduction of a live vaccine against PRRS
for baby pigs has done nothing to help the
reproductive performance of infected herds.
Ingelvac PRRS KV is the first vaccine licensed
to enhance reproductive performance
impaired by infection with the virus.
Boehringer Ingelheim is an internationally respected name in pig
health. This product launch heralds the arrival of Boehringer Ingelheim
Vetmedica as a fully committed partner to pig producers in the UK. |
Reproductive loss through PRRS
Acute PRRS in the breeding herd can cause death and
resorption of the foetuses when the virus infects them at an
early stage of gestation. It is then associated with an early
return to oestrus of the sows and reduced farrowing rates.
The virus is especially pathogenic during the second half
of gestation: late infection (around day 90) can cause
haemorrhagic lesions of the umbilical cord and so lead
to abortions, early farrowing (by 3-5 days), an increase
in stillbirths, mummies and pre-weaning mortality.
It therefore results in a decrease in total births, live births
and weaned litter sizes. Furthermore, piglets born to
infected animals often show increased susceptibility to
secondary infections.
Respiratory
Suckling and fattening pigs suffer respiratory symptoms
and death due to PRRS infection contracted from virus
circulating in the herd. Respiratory symptoms are often
aggravated by secondary infections, possibly due to
impairment of macrophages in the lung. |
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‘The Blue Eared Pig Disease’
The names given to the disease often have some
reference to blue ears. One of the early clinical
signs included a blue discoloration of the ears.
 ‘Reproductive PRRS’
Reproductive PRRS is associated with abortions,
weak and stillborn piglets, early farrowing and
a reduction of other reproductive parameters.
 ‘Secondary Infections’
Piglets from infected sows are prone to secondary
infections such as Streptococcus suis, APP,
Enzootic Pneumonia, Haemophilus parasuis, etc.
‘Respiratory PRRS’
Respiratory PRRS is characterised by difficulty
in breathing, eyelid oedema, sneezing, pyrexia,
stunted growth and poor food conversion.
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Clinical Symptoms in the Breeding Herd
(Note: the number and the severity of these symptoms can vary greatly, depending on the PRRS status of the farm)
Not only is PRRS a problem in its own right but there is increasing
evidence that it is an important co-factor in the development of
Post Weaning Multi-Systemic Wasting Syndrome (PMWS).
Co-infections with PRRS Virus and Porcine Circo Virus 2 (PCV2)
are now thought to be the main causative agents of the syndrome.
This has been observed by several different authors and in various
countries. Experimental dual infection with both viruses has been
shown to potentiate the replication of PCV2 which could explain the
fact that PMWS seems to be clinically more severe in cases of
co-infections with PCV2 and PRRSV compared to infections with
PCV2 alone. PMWS is an increasingly important issue in UK pig
herds, quickly spreading and causing significant economic loss.
How to diagnose PRRS?
Different diagnostic tools are available to differentiate PRRS
infection from other diseases. A tentative diagnosis is made on the
basis of clinical signs such as maternal reproductive failure and
respiratory disease in growing pigs. Definitive diagnosis however,
requires further diagnostic tests carried out on materials from
infected animals.
Why is it important to test for PRRS?
Many infected herds show clinical signs that are easily confused
with other swine diseases. Knowing the herd status is an important
aid in determining the most appropriate course of action.
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