Serum based screening and molecular detection of brucellosis in ruminants

22-25Brucellosis is a highly infectious bacterial disease that mainly affects cattle, sheep, pigs, goats, dogs, horses and wild animals primarily caused by Brucella abortus, B. ovis, B. suis, B. melitensis, and B. canis. It has a significant threat to the livestock and human community mainly in developing countries and requires accurate diagnosis, characterization and management. This study was undertaken in 238 samples (112 serum samples from the sheep, 82 serum samples from the goat and 44 serum samples from the cattle) suspected of brucellosis collected from the southern districts of Tamil Nadu. All the 238 samples were screened for the brucellosis by carrying out rose bengal plate agglutination test (RBPT). The seropositive serum samples were further subjected to Brucella cell surface salt extractable protein 31 (BCSP 31) gene-based PCR for Brucella genus confirmation. The BCSP 31-PCR positive samples were further subjected to Brucella-AMOS (avis-melitensis-ovis-suis) multiplex PCR for identification of B. abortus, B. ovis, B. melitensis and B. suis species. The study revealed that 8.92% (n = 10) serum samples from sheep, 9.75% (n = 8) serum samples from goat and 6.81% (n = 3) serum samples from cattle were seropositive for brucellosis by RBPT. All the twenty one seropositive samples produced specific amplicon of 223 bp by BCSP 31-PCR confirms brucellosis. Further molecular typing of BCSP 31-PCR positive samples by Brucella –AMOS  PCR revealed specific amplicon of 498 bp indicating the involvement of B. abortus in 19 serum (10 from sheep, 6 from goat and 3 from cattle) samples. One serum sample from goat revealed specific amplicons of 498 bp and 731 bp indicating the involvement of both B. abortus and B. meletensis. Another serum sample from goat yielded specific amplicons of 498 bp, 731 bp and 285 bp suggesting the mixed infection of B. abortus, B. meletensis and B. suis, respectively. The B. abortus is the common species involved in cattle, sheep and goat infections. Two caprine samples showed mixed infection which involves B. abortus, B. meletensis and B. suis species. The study concludes that the serum can be used as an alternate specimen for the fast and reliable molecular diagnosis of brucellosis

Incidence of egg drop syndrome – 1976 in Namakkal district, Tamil Nadu, India

Aim: To know the magnitude of influence by Egg Drop Syndrome – 1976 (EDS –'76) virus infection in causing drop in egg production in and around Namakkal. Materials and Methods: A total of 150 cloacal swabs and 15 pouch shell glands (uteri) homogenates from 15 poultry farms in and around Namakkal area were used for virus isolation. Three numbers of 10 –day- old embryonated duck eggs were used for the inoculation of each suspected material for virus isolation. The isolate was identified by HA property, by specific inhibition of HA and by AGPT using hyperimmune serum raised against reference EDS –'76 virus strain 127. Results: Out of samples from 15 farms only one isolate (6.6%) was obtained from poultry farm No.5. Conclusion: The results of the present study revealed that the EDS –'76 virus influence in causing drop in egg production in this area to be minimal. [Vet World 2013; 6(6.000): 350-353

Evaluation of an inactivated vaccine for nephropathogenic infectious bronchitis virus

Aim: To evaluate an inactivated vaccine for nephropathogenic infectious bronchitis in broiler with special reference to its ability for passing maternal antibodies to broiler chicks. Materials and Methods: An inactivated vaccine against nephropathogenic infectious bronchitis (NIB), prepared using an isolate obtained from natural outbreak of NIB was administered to broiler parents at the point of lay, leaving the control birds unvaccinated. Eggs laid below the desired weight (> 52 g) by vaccinated hens were utilized for yolk serology. Chicks obtained from hens of both group were subjected for serology and challenge with wild type of nephropathogenic IB isolates. Serology of the yolk and serum was carried out using haemagglutination (HI) test and ELISA. Results: Yolk serology revealed a geometric mean titre of 415.9 and 15188±768 in HI test and ELISA respectively on 28 days post vaccination (dpv) as against 16.0 and 1881±86 in yolk from unvaccinated hens. The HI test and ELISA indicated that the level of maternal antibody (MAb) in the chicks obtained from vaccinated hens was significantly (P< 0.01) higher on seven days of age than that of chicks from unvaccinated hens. However, the level of Mab of the chicks obtained from vaccinated hens decreased to below the level of protection at two weeks of age. Wild isolate and another isolate obtained from different geographical area were used for challenge dividing the chicks from vaccinated and unvaccinated hens equally. Mortality was observed in the challenged chicks from vaccinated (one in heterologus challenge) and unvaccinated (two) hens. Examination of kidney specimens collected from dead chicks revealed mottling and severe congestion grossly and inflammatory, degenerative and necrotic changes microscopically. Conclusion: The partial cross-protection against heterologous challenge and incomplete protection against homologous challenge with wild isolates were noticed. [Vet World 2013; 6(3.000): 134-138

Studies on the effectiveness of oral pellet vaccine in improving egg production and egg quality in desi chicken

Aim: To study the effect of Newcastle disease (ND) oral pellet vaccine in egg production and egg quality in desi chicken. Materials and Methods: The study was conducted at Veterinary University Training and Research Centre, Tiruchirapalli, Tamil Nadu. A total of 48-day-old desi chicks obtained from a private hatchery in Namakkal, Tamil Nadu, were maintained under cage system of rearing up to 52 weeks of age as per standard management practices. All the 48 chicks were divided into six groups having eight chicks in each group were subjected to different treatment regimes. All the birds were challenged at 52 weeks of age with 0.5 ml dose of 104.0 egg infectious dose 50 virulent ND field virus. 10 eggs from each group were randomly collected during the last 3 days of 8 weeks interval period from 28 to 52 weeks of age and were used to measure the egg quality parameters. The production performance of each group was assessed at 4 weeks interval period from 25 to 52 weeks of age. Results: In all the six treatment groups with respect to egg production, no significant difference (p≥0.05) was noticed from 25 to 52 weeks of age. Similarly, in egg weight, egg shape index and specific gravity, no significant difference (p≥0.05) was noticed from 28 to 52 weeks of age. Conclusion: From this study, it is concluded that the administration of ND oral pellet vaccine to desi chicken does not affect the egg production performance, egg weight, egg shape index, and specific gravity of egg

Complete nucleotide sequence analysis of the oncogene <i>“Meq”</i> from serotype 1 Marek’s disease virus isolates from India

<p>1. A study was undertaken to characterise the oncogene <i>Meq</i> at the molecular level for three serotype 1 Marek’s disease virus (MDV) field isolates from vaccinated poultry flocks which had encountered a Marek’s disease outbreak in the southern part of India. The isolates were named Ind/TN/11/01, Ind/KA/12/02 and Ind/TN/12/03. The oncogene <i>Meq</i> was amplified by PCR and sequenced.</p> <p>2. The isolates were shown to have a homology for the <i>Meq</i> gene of 99.1–99.8% with various isolates from China and 98.5–99.2% with isolates from Europe and the USA. Alignment analysis of the nucleotide sequences showed that nucleotide mutations at 5 different positions in the <i>Meq</i> gene displayed perfect regularity in MDVs circulating in the southern part of India, which could be considered as features of field MDVs recently prevalent in this area.</p> <p>3. In addition, the mutation in the <i>Meq</i> gene at positions 251, 260 and 437 was unique and coincides with very virulent strains from China GX0101, GXY2 and a Hungarian strain ATE. The mutation at positions 283 and 300 was unique and coincides with the very virulent strain ATE of Hungary. There were also single nucleotide mutations at positions 155 (A–T), 369 (A–C), 462 (C–A) and 548 (C–T) observed in the isolate Ind/TN/12/03.</p> <p>4. Phylogenetic analysis of <i>Meq</i> sequences revealed that field MDVs in this area evolved independently but have similarities with very virulent strains from China, and that <i>Meq</i> has more similarities with the very virulent Hungarian strain.</p