136 www.roavs.com EISSN: 2223-0343 RESEA RCH OPINIONS IN A NIMA L & VETERINA RY SCIENCES Comparative study on the haematology and persistence of velogenic Newcastle disease virus in chickens and guinea fowls A. O. Igwe 1 , W.S. Ezema 2*, J. I. Ibu 3 , J. I. Eze 4 and J.O.A. Okoye 2 1 Department of Veterinary Pathology, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria, 2 Department of Veterinary Pathology and Microbiology, University of Nigeria, Nsukka; 3 Virology Division, National Veterinary Research Institute, Vom, Plateau State, Nigeria; 4 Department of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria Abstract Six weeks old cockerels and guinea fowls were inoculated intramuscularly with a local Nigerian strain of velogenic Newcastle disease virus (VNDV). Thereafter a comparative study of virus isolation in the tissues, detection in cloacal swabs and haematological changes were studied. The virus was isolated more frequently in the lung/trachea of the cockerels than guinea fowls. But the frequency of isolation from the bursa, thymus, spleen and brain in the two species was virtually the same. The highest concentration of the virus occurred in the bursa of the infected cockerels on days 3 and 6 post infection (PI). No virus was isolated from the two species after day 15 PI. Suspensions of the cloacal swabs showed heamagglutination (HA) activity from days 3 to 15 PI. The highest concentration of the virus was obtained on day 10 PI in both species.The infection produced no significant changes in the packed cell volume (PCV), haemoglobin concentration (HbC) and red blood cell (RBC) count in both species (p>0.05). But the infection in both species produced leucocytosis, heterophilia and lymphopenia (P<0.05). The above observations show that despite the fact that the infection is more severe in the cockerels; the pathogenesis of the infection in both species is very similar. Keywords: velogenic Newcastle disease virus; haematology; guinea fowl; cockerel To cite this article: Igwe AO, WS Ezema, JI Ibu, JI Eze and JOA Okoye, 2013. Comparative study on the haematology and persistence of velogenic newcastle disease virus in chickens and guinea fowls. Res. Opin. Anim. Vet. Sci., 3(5), 136-142. Introduction Velogenic Newcastle disease (VND) is a major problem of poultry in many parts of the world (Alexander and Senne, 2008). The causative agent of the disease is velogenic Newcastle disease (ND) virus (VNDV) which is the prototype virus of the avian paramyxovirus type 1 in the family Paramyxoviridae (Lamb et al., 2005; Alexander and Senne, 2008). While the disease is enzootic in Africa and Asia (Bell, 1988; Echeonwu et al., 1993; Mathivanan et al., 2004), it is exotic in Europe and North America. Despite the advances made so far in the control of the disease by vaccination and biosecurity, devastating outbreaks of VND still occur in many parts of the world (Capua et al., 2002). This is because there are many factors that make the control of VND very difficult. VNDV has a very wide host range, affecting at least 241 avian species (Alexander and Senne, 2008). The disease is clinical in some species but sub and none clinical in others. The later hosts carry the highly pathogenic virus and serve as reservoirs of infection to susceptible birds. Our recent studies have also shown that La Sota vaccine protects against the clinical manifestations of VND but does not prevent the occurrence of severe atrophy of the lymphoid organs which is one of the major lesions of the clinical disease (Ezema et al., 2008). Furthermore, no pathognomonic lesion has been described for VND. The disease manifests in different forms in various avian species where they resemble Corresponding author: WS Ezema, Department of Veterinary Pathology and Microbiology, University of Nigeria, Nsukka, Nigeria