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Pathogenicity of the Border Disease Agent for the Bovine Foetus
Br. vet.
J. (1974),
130 ,
357
PATHOGENICITY OF THE BORDER DISEASE AGENT FOR THE BOVINE FOETUS By
D.
F.
GIBBONS *, C.
E.
V\TI NKLER*,
1.
S. TERLECKI, CAROL RI C HARDSON, AND
G. SHAW*,
J.
T. DONE
• Veterinary Investigation Centre, Worcester, and Central Veterinary Laboratory, Weybridge
SUMMARY
Ten pregnant heifers were inoculated intramuscularly at 50-5I days gestation with an emulsion of tissues from lambs affected with ovine Border Disease (BD ); the same inoculum was used to inject 24 pregnant ewes at 25-40 days gestation. Six of the cows aborted between I I7 and 264 days gestation and three more showed evidence of foetal death between I I7 and I76 days; only one produced a live healthy calf at term. All the bovine foetuses showed severe growth retardation, and in three there was gross bilaterally symmetrical cavitation of the cerebrum. All the cows developed antibodies to bovine virus diarrhoea virus. It is concluded that the BD agent could be a potentially serious cause of reproductive failure in cattle which merits further investigation. INTROD UCT IO N
Border Disease (BD) is a congenital condition of lambs which, in its typical form, is characterized clinically by tremor ("shaking"), hairy birthcoat and abnormal body conformation, a nd pathologically by defective m yelination of the central nervous system. Foetal death with or without observed abortion is also an essential part of the syndrome. Experimentally the disease can be transmitted with tissue suspensions from affected lambs. The causal agent is believed to be a virus which recent studies (H amilton & Timoney, 1972; Plant et al., 1973) suggest is antigenically related to the virus of bovine virus diarrhoeal mucosal disease (BVD /MD ). BD as such has been reported only in lambs but, as cattle commonly graze with sheep and epidemics of congenital nervous diseases of calves have been observed in circumstances suggestive of transplacental infection, it was considered that the BD agent might also be a potential pathogen for the bovine foetus. This hypothesis has been tested and the results are briefly reported in this p aper.
MATERIALS AND METHODS
T en I4- I6-month-oldJersey heifers, purchased from an Accredited Brucellosisfree herd, were mated by A.I. to the same bull and, when 50 days pregnant,
BRITISH VETERINARY JOURNAL, 130, 4
inoculated intramuscularly with 20 ml of a 20 per cent suspension of tissues (brain, spinal cord, kidney, spleen and liver) from two BD lambs. Concurrently, 24 Dorset H orn ewes from a BD-free flock were also inoculated with aliquots of the same suspension (1 0 ml intramuscularly) at 25-40 d ays gestation to serve as positive controls. RESULTS
The inoculum proved highly pathogenic in sheep; 23 of 24 ewes aborted dead foetuses or were found empty at term; the remaining one produced healthy twins . Of the cows, six aborted between I 17 and 264 days of gestation and three more showed signs indicative of foetal loss between I 17 and 176 days; the remaining one produced a live, healthy calf at term (Table I ). None of the adult animals showed any clinical signs of disease. TABLE I RESUL TS OF INOC UL ATIO N OF
Cow No. I
2 3 4 5 6 7 8 9 10
10
HEIFERS
WITH MATERIA L FROM BD
LAM BS
Inoculation Gest. age in days
Abortion/birth Gest. age in days
Est. developmental age of* foetus in days
Est. conceptual age at foetal t death in days
50 50 50 50 50 50 51 50 50 51
117 166 26 4 ..;; 176 279 23 1 12 9 ..;; 121 249 < 11 7
102 118 20 3
0 0 262
279 189 68
279 225 0
202
23 6
* Based on four parameters viz: ( I) Weight, (2 ) Crown-anal length, (3 ) Length of long bones, (4 ) O ssification centres. t Based on extent of autolytic change of foetus . o = Unknown-mummified foetus. - = No foetus found. The ovine and bovine foetuses showed evidence of severe growth retardation. Figures for bodyweight, crown-anus length, long bone length a nd ossification centres obtained in the three bovine foetuses which died latest in gestation (Nos. 3, 6, and 9) were examined in detail and were comparable with those reported by various authors for foetuses 30- 60 days younger. Radiographically most of the long bones showed "growth arrest lines" indicative of abnormal osteogenesis; there were also abnormalities of the cranial bones and the skull as a whole. All the visceral organs appeared grossly and histologically normal. One of the brains (No. 3) was abnormally shaped overall and one (No.9) had a deep depression on the dorsal aspect of the frontal lobe of the cerebrum; all three showed gross bilaterally symmetrical cavitation of the cerebral white matter at the occipital level (Fig. I ). The cerebella appeared well formed; in each case the cerebellum : brain ratio was approximat ely I : ro. Histological examination of brain tissues of foetuses Nos. 3 and 9 showed that
PATHOGENICITY OF BORDER DISEASE FOR CATTLE
359
with the exception of the d epressed area in brain NO. 9 in which there was extensive neuronal necrosis in the cortex, cerebral lesions in both brains were generally restricted to the white matter. These consisted essentially of oedema, which was particularly severe in the occipital lobe, giving the area a spongy appearance and leading in places to microcavitation. The area surrounding the large cavities showed thin nerve fibres, most of them devoid of myelin, many of them fragmented with scattered among them a few round or elongated bodies which stained as for axons cylinders. There was no macrophage reaction and no osmiophilic material could be demonstrated. In brain NO.3 there were also significant cerebellar lesions. These consisted of necrosis of single Purkinje cells with encrustation of their d endritic tree, rarefaction of the internal granular layer and oedema of the central core of white matter with local axonal swelling. There were no significant changes in the spinal cord. In Nos. 3 and 9 very large areas of the placenta were covered by compensatory intercotyledonary placentation; there were very few cotyledons well d eveloped and shaped. Both placentae showed foci of necrosis. Tests of pre- and post-inoculation sera showed that all cows developed antibodies to BVD virus. DI SCUSS IO N
The inoculum used in this experiment was highly pathogenic for both bovine and ovine foetuses. Though no hairy-shaker lambs were produced, the foetopathic effects in sheep were consistent with Border Disease. As in sh eep the syndrome in cattle was one of foetal dysmorphogenesis and death, with abortion resulting from failure of the conceptus. Workers in America have reported transplacental infection and foetal damage following exposure of pregnant cows to BVD /MD viruses. In some cases nervous damage, for example cerebellar hypoplasia, resulted (K ahrs, Scott & de Lahunta, 1970); in others the foetal lesions were mainly mucosal, visceral or cutaneous (Casaro, K endrick & K ennedy, 1971). The somewhat different picture produced in our experiment may refl ect differences in the size and timing of the infective dose and/or a variation in the infective agent. Though BD has been shown to be immunologically rela ted to BVD there is at present no reason to believe tha t the relationship is closer than that between BVD and swine fever viruses. This preliminary work indicates that experimentally BD is highly pathogenic for the bovine foetus in its own right and hence constitutes a potentially serious cause of reproductive failure in cattle which merits further investigation. ACKNOWLEDGEMENTS
We are grateful to Messrs P. Stuart and R. A. Huck, of the D epartment of Virology, M .A.F.F. Central Veterinary Laboratory for examining the cattle and sh .ep sera for antibodies to BVD virus, and to Mr. R. Sayer for the photograph.
BRITI SH VETERINARY J OURNAL, 130, 4 REFERENCES CASARO, A. P. E., KENDRICK, J. W. & KENNEDY, P. C. (1971 ) . Am. J. vet. Res. 3 2 , 1543. HAMILTON, A . & TIMONEY, P. J. (1972 ). Vet. Rec. 91, 468. KAHRS, R. F., SCOTT, F. W. & DE LAHUNTA, A. (1970). J. Am. vet. med. Ass. 156, 851, 1443. PLANT, J . W., LITTLE]OHNS, I. R., GARDINER, A. C., VANTSIS, J. T . & HUCK, R. A. (1973) . Vet. Rec. 92, 455 . (Acceptedfor publication 21 February 1974)
Pathogenie de l'agent de la Maladie de Border chez Ie foetus bovin (Gibbons et 01.) Resunte. On inocula par voie intramusculaire dix genisses en gestation aux 50-51 jours de cette derniere, avec une emulsion obtenue a partir de tissus d'agneaux atteints par la Maladie ovine de Border (MB); on injecta cette meme emulsion a 24 brebis en gestation aux25-40 jours de cette derniere. Six des genisses avorterent entre Ie 117 et 264 jours de gestation et trois de plus montrerent des signes evidents de mort foetale entre Ie 117 et 176 jours; une seule mit bas a terme une vache vivante en bonne sante. Tous les foe tus bovins montrerent un retard de croissance severe, et chez trois d'entre eux il existait une cavitation importante bilaterale et symetrique du cerveau. Toutes les vaches developperent des anti-corps anti-virus bovin, anti-virus diarrheique. II en est conclu que I'agent de la MB pourrait etre une cause serieuse de chute de la reproduction chez Ie betail, cause qui merite une investigation plus poussee.
Die Pathogenitiit des Grenzerkrankungs-Erregers bei· Rinderfoeten (Gibbons et 01.) Zuss antntenfass ung. Zehn trachtige Farsen wurden intramuskular am 50.- 51. Tag der Trachtigkeit mie einer Aufschwemmung von Gewebe von Lammern geimpft, die von der Grenzerkrankung (Border-Disease) der Rinder befallen waren; der gleiche I mpfstoff wurde 24 trachtigen Mutterschaften am 25.-40. Tage der Trachtigkeit injiziert. Sechs von den Ktihen abortierten zwischem dem I 17. und 176. Tage; nur eine warf ein voll ausgetragenes gesundes Kalb. AIle Rinderfoeten zeigten starke Verlangsamung der Entwicklung und bei dreien zeigten sich bilateral symmetrische gross Hohlenbildungen im Gehirn. Samtliche Ktihe entwickelten Antikorper gegen das Virus der Virusdiarrhoe der Rinder. Es wird angenommen, dass der BD-Erreger eine potentiell ernste Ursache der versagenden Vermehrung der Rinder sein konnte und dass weitere Untersuchungen notig sind.
Patogenicidad del agente de la enferntedad fronteriza en el feto bovino (Gibbons et 01.) Resunten. Se inocularon por via intramuscular diez novillas prefiadas a los 50-51 dias de gestaci6n con una emulsi6n de tejidos procedentes de corderos afectados por la enfermedad fronteriza (Border Disease: BD) ovina; se emple6 el mismo inoculo para inyectar a 24 ovejas prefiados a los 25- 40 dias de gestaci6n. Seis vacas abortaron entre los 117 y 264 dias de gestaci6n, y tres mas mostraron sefias de muerte fetal entre los 117 y 176 dias; solamente una di6 a luz un ternero vivo y sa no al final normal de la gestaci6n. Todos los fetos bovinos mostraron una grave retardaci6n del crecimiento, yen tres de ell os se observ6 una seria cavitaci6n del cerebro bilateralmente simetrica. Todas las vacas desarrollaron anticuerpos contra el virus bovino de diarrea. Se concluye que el agente BD pudiera ser una causa potencialmente grave de perdida reproductiva en el ganado que rn erece mayor investigaci6n.
PLATE I
Fig.
I .
Foetus
o. 3. Cerebr um. Bila tera lly symme trical gross cavitation of the white matter. X
It .
Gibbons et al., Br. vet.
J. (1974),13°,
4
J. (1974),
130 ,
357
PATHOGENICITY OF THE BORDER DISEASE AGENT FOR THE BOVINE FOETUS By
D.
F.
GIBBONS *, C.
E.
V\TI NKLER*,
1.
S. TERLECKI, CAROL RI C HARDSON, AND
G. SHAW*,
J.
T. DONE
• Veterinary Investigation Centre, Worcester, and Central Veterinary Laboratory, Weybridge
SUMMARY
Ten pregnant heifers were inoculated intramuscularly at 50-5I days gestation with an emulsion of tissues from lambs affected with ovine Border Disease (BD ); the same inoculum was used to inject 24 pregnant ewes at 25-40 days gestation. Six of the cows aborted between I I7 and 264 days gestation and three more showed evidence of foetal death between I I7 and I76 days; only one produced a live healthy calf at term. All the bovine foetuses showed severe growth retardation, and in three there was gross bilaterally symmetrical cavitation of the cerebrum. All the cows developed antibodies to bovine virus diarrhoea virus. It is concluded that the BD agent could be a potentially serious cause of reproductive failure in cattle which merits further investigation. INTROD UCT IO N
Border Disease (BD) is a congenital condition of lambs which, in its typical form, is characterized clinically by tremor ("shaking"), hairy birthcoat and abnormal body conformation, a nd pathologically by defective m yelination of the central nervous system. Foetal death with or without observed abortion is also an essential part of the syndrome. Experimentally the disease can be transmitted with tissue suspensions from affected lambs. The causal agent is believed to be a virus which recent studies (H amilton & Timoney, 1972; Plant et al., 1973) suggest is antigenically related to the virus of bovine virus diarrhoeal mucosal disease (BVD /MD ). BD as such has been reported only in lambs but, as cattle commonly graze with sheep and epidemics of congenital nervous diseases of calves have been observed in circumstances suggestive of transplacental infection, it was considered that the BD agent might also be a potential pathogen for the bovine foetus. This hypothesis has been tested and the results are briefly reported in this p aper.
MATERIALS AND METHODS
T en I4- I6-month-oldJersey heifers, purchased from an Accredited Brucellosisfree herd, were mated by A.I. to the same bull and, when 50 days pregnant,
BRITISH VETERINARY JOURNAL, 130, 4
inoculated intramuscularly with 20 ml of a 20 per cent suspension of tissues (brain, spinal cord, kidney, spleen and liver) from two BD lambs. Concurrently, 24 Dorset H orn ewes from a BD-free flock were also inoculated with aliquots of the same suspension (1 0 ml intramuscularly) at 25-40 d ays gestation to serve as positive controls. RESULTS
The inoculum proved highly pathogenic in sheep; 23 of 24 ewes aborted dead foetuses or were found empty at term; the remaining one produced healthy twins . Of the cows, six aborted between I 17 and 264 days of gestation and three more showed signs indicative of foetal loss between I 17 and 176 days; the remaining one produced a live, healthy calf at term (Table I ). None of the adult animals showed any clinical signs of disease. TABLE I RESUL TS OF INOC UL ATIO N OF
Cow No. I
2 3 4 5 6 7 8 9 10
10
HEIFERS
WITH MATERIA L FROM BD
LAM BS
Inoculation Gest. age in days
Abortion/birth Gest. age in days
Est. developmental age of* foetus in days
Est. conceptual age at foetal t death in days
50 50 50 50 50 50 51 50 50 51
117 166 26 4 ..;; 176 279 23 1 12 9 ..;; 121 249 < 11 7
102 118 20 3
0 0 262
279 189 68
279 225 0
202
23 6
* Based on four parameters viz: ( I) Weight, (2 ) Crown-anal length, (3 ) Length of long bones, (4 ) O ssification centres. t Based on extent of autolytic change of foetus . o = Unknown-mummified foetus. - = No foetus found. The ovine and bovine foetuses showed evidence of severe growth retardation. Figures for bodyweight, crown-anus length, long bone length a nd ossification centres obtained in the three bovine foetuses which died latest in gestation (Nos. 3, 6, and 9) were examined in detail and were comparable with those reported by various authors for foetuses 30- 60 days younger. Radiographically most of the long bones showed "growth arrest lines" indicative of abnormal osteogenesis; there were also abnormalities of the cranial bones and the skull as a whole. All the visceral organs appeared grossly and histologically normal. One of the brains (No. 3) was abnormally shaped overall and one (No.9) had a deep depression on the dorsal aspect of the frontal lobe of the cerebrum; all three showed gross bilaterally symmetrical cavitation of the cerebral white matter at the occipital level (Fig. I ). The cerebella appeared well formed; in each case the cerebellum : brain ratio was approximat ely I : ro. Histological examination of brain tissues of foetuses Nos. 3 and 9 showed that
PATHOGENICITY OF BORDER DISEASE FOR CATTLE
359
with the exception of the d epressed area in brain NO. 9 in which there was extensive neuronal necrosis in the cortex, cerebral lesions in both brains were generally restricted to the white matter. These consisted essentially of oedema, which was particularly severe in the occipital lobe, giving the area a spongy appearance and leading in places to microcavitation. The area surrounding the large cavities showed thin nerve fibres, most of them devoid of myelin, many of them fragmented with scattered among them a few round or elongated bodies which stained as for axons cylinders. There was no macrophage reaction and no osmiophilic material could be demonstrated. In brain NO.3 there were also significant cerebellar lesions. These consisted of necrosis of single Purkinje cells with encrustation of their d endritic tree, rarefaction of the internal granular layer and oedema of the central core of white matter with local axonal swelling. There were no significant changes in the spinal cord. In Nos. 3 and 9 very large areas of the placenta were covered by compensatory intercotyledonary placentation; there were very few cotyledons well d eveloped and shaped. Both placentae showed foci of necrosis. Tests of pre- and post-inoculation sera showed that all cows developed antibodies to BVD virus. DI SCUSS IO N
The inoculum used in this experiment was highly pathogenic for both bovine and ovine foetuses. Though no hairy-shaker lambs were produced, the foetopathic effects in sheep were consistent with Border Disease. As in sh eep the syndrome in cattle was one of foetal dysmorphogenesis and death, with abortion resulting from failure of the conceptus. Workers in America have reported transplacental infection and foetal damage following exposure of pregnant cows to BVD /MD viruses. In some cases nervous damage, for example cerebellar hypoplasia, resulted (K ahrs, Scott & de Lahunta, 1970); in others the foetal lesions were mainly mucosal, visceral or cutaneous (Casaro, K endrick & K ennedy, 1971). The somewhat different picture produced in our experiment may refl ect differences in the size and timing of the infective dose and/or a variation in the infective agent. Though BD has been shown to be immunologically rela ted to BVD there is at present no reason to believe tha t the relationship is closer than that between BVD and swine fever viruses. This preliminary work indicates that experimentally BD is highly pathogenic for the bovine foetus in its own right and hence constitutes a potentially serious cause of reproductive failure in cattle which merits further investigation. ACKNOWLEDGEMENTS
We are grateful to Messrs P. Stuart and R. A. Huck, of the D epartment of Virology, M .A.F.F. Central Veterinary Laboratory for examining the cattle and sh .ep sera for antibodies to BVD virus, and to Mr. R. Sayer for the photograph.
BRITI SH VETERINARY J OURNAL, 130, 4 REFERENCES CASARO, A. P. E., KENDRICK, J. W. & KENNEDY, P. C. (1971 ) . Am. J. vet. Res. 3 2 , 1543. HAMILTON, A . & TIMONEY, P. J. (1972 ). Vet. Rec. 91, 468. KAHRS, R. F., SCOTT, F. W. & DE LAHUNTA, A. (1970). J. Am. vet. med. Ass. 156, 851, 1443. PLANT, J . W., LITTLE]OHNS, I. R., GARDINER, A. C., VANTSIS, J. T . & HUCK, R. A. (1973) . Vet. Rec. 92, 455 . (Acceptedfor publication 21 February 1974)
Pathogenie de l'agent de la Maladie de Border chez Ie foetus bovin (Gibbons et 01.) Resunte. On inocula par voie intramusculaire dix genisses en gestation aux 50-51 jours de cette derniere, avec une emulsion obtenue a partir de tissus d'agneaux atteints par la Maladie ovine de Border (MB); on injecta cette meme emulsion a 24 brebis en gestation aux25-40 jours de cette derniere. Six des genisses avorterent entre Ie 117 et 264 jours de gestation et trois de plus montrerent des signes evidents de mort foetale entre Ie 117 et 176 jours; une seule mit bas a terme une vache vivante en bonne sante. Tous les foe tus bovins montrerent un retard de croissance severe, et chez trois d'entre eux il existait une cavitation importante bilaterale et symetrique du cerveau. Toutes les vaches developperent des anti-corps anti-virus bovin, anti-virus diarrheique. II en est conclu que I'agent de la MB pourrait etre une cause serieuse de chute de la reproduction chez Ie betail, cause qui merite une investigation plus poussee.
Die Pathogenitiit des Grenzerkrankungs-Erregers bei· Rinderfoeten (Gibbons et 01.) Zuss antntenfass ung. Zehn trachtige Farsen wurden intramuskular am 50.- 51. Tag der Trachtigkeit mie einer Aufschwemmung von Gewebe von Lammern geimpft, die von der Grenzerkrankung (Border-Disease) der Rinder befallen waren; der gleiche I mpfstoff wurde 24 trachtigen Mutterschaften am 25.-40. Tage der Trachtigkeit injiziert. Sechs von den Ktihen abortierten zwischem dem I 17. und 176. Tage; nur eine warf ein voll ausgetragenes gesundes Kalb. AIle Rinderfoeten zeigten starke Verlangsamung der Entwicklung und bei dreien zeigten sich bilateral symmetrische gross Hohlenbildungen im Gehirn. Samtliche Ktihe entwickelten Antikorper gegen das Virus der Virusdiarrhoe der Rinder. Es wird angenommen, dass der BD-Erreger eine potentiell ernste Ursache der versagenden Vermehrung der Rinder sein konnte und dass weitere Untersuchungen notig sind.
Patogenicidad del agente de la enferntedad fronteriza en el feto bovino (Gibbons et 01.) Resunten. Se inocularon por via intramuscular diez novillas prefiadas a los 50-51 dias de gestaci6n con una emulsi6n de tejidos procedentes de corderos afectados por la enfermedad fronteriza (Border Disease: BD) ovina; se emple6 el mismo inoculo para inyectar a 24 ovejas prefiados a los 25- 40 dias de gestaci6n. Seis vacas abortaron entre los 117 y 264 dias de gestaci6n, y tres mas mostraron sefias de muerte fetal entre los 117 y 176 dias; solamente una di6 a luz un ternero vivo y sa no al final normal de la gestaci6n. Todos los fetos bovinos mostraron una grave retardaci6n del crecimiento, yen tres de ell os se observ6 una seria cavitaci6n del cerebro bilateralmente simetrica. Todas las vacas desarrollaron anticuerpos contra el virus bovino de diarrea. Se concluye que el agente BD pudiera ser una causa potencialmente grave de perdida reproductiva en el ganado que rn erece mayor investigaci6n.
PLATE I
Fig.
I .
Foetus
o. 3. Cerebr um. Bila tera lly symme trical gross cavitation of the white matter. X
It .
Gibbons et al., Br. vet.
J. (1974),13°,
4