224 F
. Madec et al. Livestock Production Science 63 2000 223 –233
´ ´
` ´
´ atteints ne sont pas retires du groupe. Les medicaments s’averent inefficaces. Les lesions affectent differents organes: les
` ´ `
´ ´ ¨
poumons, la rate, les reins et surtout les ganglions lymphatiques ou on observe une severe depletion lymphoıde. La maladie `
` ´
´ ´
´ ne possede pas d’expression collective. Les premieres donnees epidemiologiques mettent en relief une susceptibilite accrue
´ ´ ´
de certaines portees. Le virus du SDRP est exclu comme agent causal au benefice d’un circovirus porcin PCV2. Les ´
´ ´ ´
´ conditions d’environnement offertes aux animaux sont suspectees decisives dans la severite de l’impact de la maladie dans
´ les elevages.
2000 Elsevier Science B.V. All rights reserved.
Keywords : Wasting syndrome; Pig; Postweaning; Epidemiology; PMWS
1. Introduction 2. Material and methods
Late in Spring 1996, two farmers complained 2.1. The farms
about unexpected mortality occurring in growing pigs in Brittany France. The pigs were two to three
Farms were selected by field veterinarians. The months old and no obvious other health disturbance
latter, in turn, had been called to these farms because could be detected in the farms. In a preliminary
of high and persistent mortality in weaned pigs study, piglets showing the first clinical signs of
despite medication. The authors visited the farms and wasting
were transferred
to our
experimental their selection was based on the willingness of the
facilities and SPF pigs of the same age were placed farmer to co-operate and also on the availability of
in contact. Surprisingly, the wasting piglets pro- information. Twelve farms in the western part of
gressively recovered without any medication, whilst France working with six different farm organisations
the contact SPF pigs became severely ill. They co-operatives were included in the survey. They
developed typical Glasser’s disease. At that time the were all farrow-to-finish operations like the majority
situation was rather confusing. Porcine Respiratory of farms in the area. On 11 farms the replacement
and Reproductive Syndrome PRRS was detected gilts came from a multiplier. On the other the
on those farms affected by the piglet wasting prob- replacement stock was home-produced. Artificial
lem as well as several other enzootic agents includ- insemination from bought-in specialised AI centres
ing M . hyopneumoniae, P. multocida, H. parasuis, S.
was widely used. The average herd size was 343 suis and enterotoxigenic E
. coli. During the second sows range 105–600. Eleven farms had intensive
half of 1996 we tried to determine the presence or confined production slatted floor, fan ventilated
absence of the specific new syndrome. Field case rooms and on one Farm 2, Table 1 the sows were
observations, often associated with experimental kept outdoors. The productivity of the herds was
trials, were designed. By the end of 1996 we came to good 24.4 piglets weaned sow year. Age at wean-
the conclusion that since the condition could be ing was either 26–28 days n
5 7 herds or 21 days transmitted to naive pigs in our facilities Le Cann et
on average n 5 5 herds. They were free of Pseu-
al., 1998, it was infectious and transmissible. Final- dorabies but 9 of them were PRRS positive. Herds
ly, the syndrome clinical signs, macroscopic lesions, No. 2, 8 and 10 were PRRS free.
histopathology was recognised as being similar to the descriptions made in North America and called
2.2. The protocol on the farms ‘‘Postweaning Multisystemic Wasting Syndrome’’
Harding, 1996, Clark, 1996. Since then, an exten- The protocol applied across the 12 farms was
sive research programme has been performed. The designed to achieve two objectives. Firstly to char-
present paper reports a series of field surveys and acterise PMWS which was new to France. No
laboratory investigations. serological test was available so we focused on other
F . Madec et al. Livestock Production Science 63 2000 223 –233
225 Table 1
Postweaning Multisystemic Wasting Syndrome: impact in 12 farms in France
a b
b
Farm Size
Productivity Age at
mortality before mortality over the
Predominant overall clinical signs
c
Nb sows piglets weaned
weaning wasting disease
3 month period after associated with wasting
sow year days
one year period wasting disease occurred
1 500
24 27.3
6.5 14.6
Diarrhoea 1 respiratory disorders
2 120
26.5 27.2
4 20.5
Diarrhoea 1 respiratory disorders
3 250
23.8 26.8
4.3 18.7
Respiratory 4
600 26.2
20.3 4.8
11.3 Not clear
5 250
24.3 21
5.1 19.6
Diarrhoea 1 respiratory
6 360
23.5 26.9
4.7 12.1
Diarrhoea 1 respiratory
7 300
24.3 28
3.8 10.2
Respiratory 8
105 24.8
26.9 3.7
12.8 Diarrhoea
1 respiratory 8
500 23.5
21 5.5
19.3 Diarrhoea
1 respiratory 11
220 24.5
27 3.2
12 Respiratory
11 600
25.2 21.1
5.6 13
Diarrhoea 1 respiratory
12 320
24.2 27
3.9 11
Not clear TOTAL
343 24.4
24.5 4.6
14.6
a
Farrow-to-finish farms.
b
Mortality for any reason from weaning to slaughter.
c
Individual signs: unthriftiness, pallor, etc . . . were present but not indicated here
laboratory examinations and clinical observations. On most of the farms, there were numerous
Retrospectively, the 12 farms were diagnosed as differences in husbandry. On four farms 3, 4, 7 and
having PMWS on histopathology and by in situ 9 the hygiene policy, space per pig, ventilation,
hybridisation using a specific circovirus type II segregation of subsequent batches and mixing of pigs
probe. The second objective was to investigate the varied and changes occurred at the different stages
epidemiology of PMWS and to try to build up suckling, weaning, fattening. The objective was not
hygiene proposals for the affected farms cohort to test the relevance of each of these changes but to
studies were carried out on these farms. The piglets look at the overall consequences of a global come-
were identified at birth. They were weighed at back to standard recommendations ITP, 1993;
weaning and then, at different times depending on Madec et al., 1999.
the farms. On farm 9, early weaning was carried out. Within the whole group of 12 farms, the prod-
The cohorts one or two per farm were visited by us uctivity and mortality data were recorded. All the
every 14 days. The farmer was asked to take special herds were managed according to a batch system
care with recording signs of illness, medications, groups of sows weaned the same day every 3
death etc. If illness occurred numerous ‘‘extra weeks; each week for the largest units, ITP, 1993
visits’’ were scheduled. A proportion of the pigs and therefore we were able to know retrospectively
dying were necropsied at the laboratory. At the end the evolution of mortality in the subsequent groups
of the critical period the pigs were weighed and bled. of contemporary pigs.
On three farms 5, 6 and 7 a more detailed protocol was applied since the pigs were visited every 2 days
2.3. The protocol at the laboratory on average during the critical phase. Rectal tempera-
ture was recorded in a group of 40 pigs randomly At the laboratory, the pigs were euthanased and
selected. The pigs were weighed at weaning, at 8 subjected to a standard necropsy. Bacteriological
weeks of age and at 12 weeks. On each occasion examination was performed on the tonsils and on
they were blood sampled. An additional blood certain viscera showing gross lesions: particularly the
sampling took place later at about 16–18 weeks. lungs and the lymph nodes.
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. Madec et al. Livestock Production Science 63 2000 223 –233
Histopathology was undertaken with special em- 3.2. The overall results of the cohort studies
phasis on lymphoid tissues associated with lung and intestine. Viral inclusions were looked for following
The total number of pigs considered was 3078. the protocol of Ellis et al. 1998.
Three hundred and thirty eight 11 died or were Lastly, an in situ hybridisation specific for cir-
sacrificed principally for animal welfare reasons. Fig. covirus Type II, was performed in cases where there
1 shows the mortality according to their age. The was microscopic damage.
twelfth week was the most critical and 68 of the losses occurred during weeks 11–13. Signs of illness
were noticed in all the piglets before death. When
3. Results recorded, rectal temperature was found to be 40.5
