Antigenetically Unusual Newcastle Disease Virus from Racing Pigeons in India

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1 Tropical Animal Health and Production, 32 (2000) 183^188 # 2000 Kluwer Academic Publishers. Printed in the Netherlands Antigenetically Unusual Newcastle Disease Virus from Racing Pigeons in India P. Roy *, A.T. Venugopalan and A. Koteeswaran Centre for Animal Health Studies, Tamilnadu Veterinary and Animal Sciences University, Madhavaram Milk Colony, Chennai , India *Correspondence: 917B South 17 Street (Hubbard Apt), Birmingham, AL 35205, USA Roy, P., Venugopalan, A.T. and Koteeswaran, A., Antigenetically unusual Newcastle disease virus from racing pigeons in India. Tropical Animal Health and Production, 32(3), 183^188 ABSTRACT Newcastle disease virus isolated from an outbreak in racing pigeons in India was found to be velogenic, based on the mean time to death in 10-day-old embryonated hen's eggs, the intravenous pathogenicity index in 6-week-old chickens and the pathogenesis in chickens and pigeons. The virus induced disease in chickens without prior adaptation in chickens. The virus was antigenically unusual since it could not be grouped with the available panel of monoclonal antibodies at the World Reference Laboratory for Newcastle disease, UK. However, commercially available lentogenic and mesogenic vaccines provided 100% protection to chickens against this antigenically unusual NDV. Keywords: chickens, Newcastle disease, pathogenicity, pigeons, protection, strain, vaccination, velogenic virus Abbreviations: AAF, amnioallantoic uid; EID 50, dose infective for 50% of chick embryos; HA, haemagglutination; HI, haemagglutination inhibition; ICPI, intracerebral pathogenicity index; IVPI, intravenous pathogenicity index; MAb, monoclonal antibody; MDT, mean time to death; NDV, Newcastle disease virus; SAN, speci c antibody-negative INTRODUCTION The natural occurrence of Newcastle disease in pigeons was rst reported in From 1971 to 1973 cases of natural infection in racing pigeons were observed in the Netherlands, Great Britain, Belgium and Germany (Vindevogel and Duchatel, 1988). The disease was panzootic by 1984 and, since 1985, it may be considered to occur worldwide (Alexander et al., 1985). This paper describes the isolation and characterization of an antigenetically unusual strain of Newcastle disease virus (NDV) from a natural outbreak in racing pigeons in India, in which the pigeons su ered from diarrhoea and nervous signs characterized by tremors of the head, torticollis and tottering steps. 183

2 184 MATERIALS AND METHODS Virus isolation Cloacal swabs collected from a ected racing pigeons were pooled and used for virus isolation in 10-day-old embryonated hen's eggs as described by Alexander (1988). Antiserum Antiserum against NDV was raised in speci c antigen-negative (SAN) chickens as described by Allan and colleagues (1978). Haemagglutination (HA) and haemagglutination inhibition (HI) tests HA and HI tests were carried out as described by Alexander (1988). Amnioallantoic uid (AAF) was harvested from inoculated embryos that died more than 24 h after inoculation. AAF was tested for HA with 1% chicken erythrocytes. HA-positive materials were con rmed as NDV by inhibition of HA activity with NDV-speci c antiserum in HI tests. The HI test was also used to assess the antibody level against NDV in serum samples. Pathogenicity tests Fresh AAF was used for pathogenicity tests. The mean time to death (MDT) in 10-dayold embryonated hen's eggs, the intracerebral pathogenicity index (ICPI) in day-old chicks and the intravenous pathogenicity index (IVPI) in 6-week-old chickens were assessed as described by Alexander (1988). Pathogenesis in chickens and pigeons Five 6-week-old SAN chickens and ve adult pigeons were infected intramuscularly with 10 5 EID 50 of the pigeon-ndv isolate. The development of clinical disease and any gross pathological lesions were recorded. Virus isolation from dead birds was done in 10-day-old embryonated hen's eggs. Monoclonal antibody (MAb) typing The isolate was subject to MAb typing at the World Reference Laboratory for Newcastle disease at the Central Veterinary Laboratory (CVL) Weybridge, UK, by courtesy of Dr R. Manvell.

3 185 Vaccination and challenge trial Trial 1: Thirty day-old White Leghorn chicks with residual maternal antibody were divided into two equal groups, which were respectively vaccinated and unvaccinated. The vaccinated groups received LaSota vaccine, obtained from the Institute of Veterinary Preventive Medicine (IVPM), Tamilnadu, India, oculonasally at 17 days of age, following the manufacturer's recommendation. The unvaccinated, age-matched birds were kept separately and served as a control group. Five chickens from each group were challenged with 10 5 EID 50 of the NDV isolate from the pigeons at 38 days of age. Ten serum samples were collected at random from both groups at 17 and 38 days of age and from the ve surviving birds at 52 days of age. The serum samples were subjected to the HI test to assess the antibody activity against NDV. Trial 2: Thirty day-old White Leghorn chicks with residual maternal antibody were divided into two groups, each comprising 15 chicks. The vaccinated group received RDVF (lentogenic vaccine) at 7 days of age and RDVK (mesogenic vaccine) at 56 days of age, following the recommendation of the manufacturers. Both the RDVF and RDVK vaccines were obtained from the IVPM, Tamilnadu, India. The other, unvaccinated, group, served as a control. Five birds from each group were challenged with 10 5 EID 50 of pigeon NDV isolate at 77 days of age and all the birds were observed for another 21 days. Ten serum samples were collected from each group at random at 7, 28, 56 and 77 days of age and ve samples from ve surviving birds in the vaccinated group at 98 days of age. The serum samples were subjected to the HI test. RESULTS Isolation and identi cation of the virus Inoculated embryos all died by 60 h after inoculation. Congestion of the extremities and in the occipital region of the embryos was prominent. Fresh AAF harvested from the inoculated embryos agglutinated chicken erythrocytes. This HA activity was inhibited by NDV-speci c antiserum in the HI test. Pathogenesis in chickens and pigeons All the infected chickens and pigeons developed clinical signs by 3^4 days after infection and died by 4^5 days after infection. On necropsy, the predominant lesions included petechial haemorrhages on the proventriculus and caecal tonsils in chickens and mild congestion of the intestine in pigeons. NDV could be isolated from the carcases of both chickens and pigeons by embryo inoculation.

4 186 Pathogenicity tests The MDT, ICPI and IVPI values of the NDV of pigeon origin were 60 h, 1.4 and 2.43, respectively. Monoclonal antibody typing The isolate was con rmed as a paramyxovirus-1 (PMV-1) with a polyclonal serum. The isolate was inhibited by MAb U85 (speci c for most classical strains of NDV) but not by MAb 617/161 (speci c for the virus responsible for the epizootic in pigeons) or MAb 7D4 (speci c for the F and LaSota strain of NDV). The isolate showed a di erent binding pattern in the indirect immunoperoxidase test with all these MAbs and could not be grouped by the methods described by Russell and Alexander (1983) and Russell and colleagues (1990). TABLE I Protection by commercial LaSota vaccine against the pigeon NDV isolate Age of birds Vaccinated GM-HI titre Unvaccinated GM-HI titre (days) (log 2 ) (log 2 ) Nil a a Unvaccinated control birds died 4 days after challenge at 38 days of age TABLE II Protection by commercial RDVK mesogenic vaccine against the pigeon NDV isolate Age of birds Vaccinated GM-HI titre Unvaccinated GM-HI titre (days) (log 2 ) (log 2 ) Nil Nil Nil a a Unvaccinated birds died 5 days after challenge at 77 days of age

5 187 Protection by vaccination The serological results are presented in Tables I and II, respectively. All the vaccinated birds (both lentogenic and mesogenic) withstood challenge, but all the unvaccinated birds succumbed to the challenge. DISCUSSION The NDV isolate obtained from the a ected racing pigeons would be regarded as velogenic since the MDT was 60 h and the IVPI more than 2.0 (Hanson and Brandly, 1955; Alexander, 1989). However, the ICPI values of 1.4 would indicate that the isolate was mesogenic. Alexander and colleagues (1985) have shown that the ICPI of 51 `pigeon' PMV-1 strains from 15 countries present a fairly compact distribution around the mean of 1.44, whereas the IVPI varies from 0.00 to Our ndings are in agreement with these earlier reports. The `pigeon' PMV-1 isolate strains isolated from Italian pigeons in 1981, and most of the Belgian, French and German strains isolated in 1983 and 1984, were characterized as mesogenic for chickens (Vindevogel and Duchatel, 1988). Earlier it was reported that the `pigeon' NDV did not induce disease in intramuscularly inoculated chickens without adaptation to chickens (Alexander et al., 1985; Buonavoglia et al., 1991). The present pigeon NDV isolate induced disease in chickens without prior adaptation. The binding pattern with the panel of MAbs of the NDV (PMV-1) isolates from pigeons gave a unique pattern (Russell and Alexander, 1983) and they were designated group-p. Group-P viruses have been found a ecting pigeons in Great Britain, Belgium, Germany, Denmark, Sweden, Norway, Italy, Portugal, Spain, Switzerland, Austria, Hungary, France, Holland, Czechoslovakia, Israel, Egypt, Sudan, Uganda, South Africa, Hong Kong, Japan, Canada and the United States (Alexander et al., 1984, 1985, 1987). The present pigeon isolate was con rmed as NDV (PMV-1) at the World Reference Laboratory (CVL), but it showed a di erent binding pattern from other NDVs with the available panel of MAbs at the CVL, Weybridge, UK and it could not be grouped. This antigenically unusual NDV (PMV-1) isolate was responsible for the outbreak in pigeons and was infective for chickens. However, currently available commercial vaccines gave full protection to chickens. ACKNOWLEDGEMENT The authors are grateful to Ruth Manvell, Avian Virology, CVL, UK for characterizing the NDV isolate.

6 188 REFERENCES Alexander, D.J., Newcastle disease diagnosis. In: D.J. Alexander (ed.), Newcastle Disease, (Kluwer Academic Publishers, Boston), 147^160 Alexander, D.J., Newcastle disease. In: H.G. Purchase, L.H. Arp, C.H. Domermuth and J.E. Pearson (eds), A Laboratory Manual for the Isolation and Identi cation of Avian Pathogens, 3rd edn, (AAAP, Kennett Square, CA, USA), 114^120 Alexander, D.J., Wilson, G.W.C., Thain, J.A. and Lister, S.A., Avian paramyxovirus type-1 isolated from pigeons ^ 3. Epizootiological considerations. Veterinary Record, 115, 213^216 Alexander, D.J. and 25 others, Antigenic and biological characterisation of avian paramyxovirus type-1 isolated from pigeons ^ an international collaborative study. Avian Pathology, 14, 365^376 Alexander, D.J., Manvell, R.J., Kemp, P.A., Parsons, G., Collins, M.S., Brackman, S., Russell, P.H. and Lister, S.A., Use of monoclonal antibodies in the characterisation of avian paramyxovirus type-1 (Newcastle disease virus) isolates submitted to an International Reference Laboratory. Avian Pathology, 16, 553^565 Allan, W.H., Lancaster, J.E. and Toth, B., Newcastle Disease Vaccines, Their Production and Use, (FAO Animal Production and Health Series, No. 10, Food and Agriculture Organisation of the United Nations, Rome) Buonavoglia, C.D.I., Trani, L., Buonavoglia, D., Tempesta, M. and Marsilio, F., Characterisation of Newcastle disease viruses isolated from pigeons in Italy. Microbiology, 14, 253^256 Hanson, R.P. and Brandly, C.A., Identi cation of vaccine strains of Newcastle disease virus. Science, 122, 156^157 Russell, P.H. and Alexander, D.J., Antigenic variation of Newcastle disease virus strains detected by monoclonal antibodies. Archives in Virology, 67, 243^253 Russell, P.H., Samson, A.C.R. and Alexander, D.J., Newcastle disease virus variations. Applied Virology Research, 2, 177^195 Vindevogel, H. and Duchatel, J.P., Panzootic Newcastle disease virus in pigeons. In: D.J. Alexander (ed.), Newcastle Disease, (Kluwer Academic Publishers, Boston), 184^196 (Accepted: 20 May 1999) Etude d'un variant antigënique du virus de la maladie de Newcastle chez des pigeons de course en Inde Re sumë ^ Un virus de la maladie de Newcastle (NDV), a pathologie rapide (base e sur la date de la mort d'oeufs embryonne s de 10 jours) fut isole chez des pigeons de course en Inde. L'index de pathogënicitë intraveineuse chez des poulets de six semaines et la pathologie chez des pigeons et des poulets adultes furent aussi e tudie s. Le virus induisit la maladie chez les poulets sans avoir e te adapte au pre alable sur cet animal. Le virus ëtait di ërent d'un point de vue antige nique car aucun des anticorps monoclonaux utilisables au centre mondial de rëfërence pour la maladie de Newcastle ne le reconnurent. Cependant des vaccins commerciaux donne rent une protection de 100% contre ce virus antige niquement inhabituel. Virus de la enfermedad de Newcastle inusual desde el punto de vista antige nico en palomas mensajeras en la India Resumen ^ El virus de la enfermedad de Newcastle (NDV) aislado de un brote en palomas mensajeras en la India se caracterizo como veloge nico, en funciön del tiempo medio hasta la muerte en huevos fecundados de diez d as, el ndice de patogenicidad intravenosa en pollos de seis semanas y la patogënesis en pollos y palomas. El virus provocö enfermedad en pollos sin previa adaptacio n. El virus fue antige nicamente inusual ya que no pudo ser incluido en el panel de anticuerpos monoclonales disponible en el laboratorio de referencia mundial para la enfermedad en Newcastle, UK. No obstante, las vacunas lentoge nicas y mesogënicas disponibles comercialmente proveyeron un 100% de proteccio n a pollos contra este ant geno inusual de NDV.

Studies on Thermostability of Newcastle Disease Viruses (Local Isolates) for Preparation of Vaccine

Studies on Thermostability of Newcastle Disease Viruses (Local Isolates) for Preparation of Vaccine International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 7 Number 01 (2018) Journal homepage: http://www.ijcmas.com Original Research Article https://doi.org/10.20546/ijcmas.2018.701.060