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Background and Aim: Newcastle disease virus (NDV) remains a major viral disease of poultry. The morbidity and mortality rates of chickens vaccinated with NDV in broiler farms in Diyala Province were 100% and 80%, respectively, rates due to suspected infection with the highly virulent NDV. The present study aimed to isolate and identify the NDV virus and evaluate its pathogenicity in infected broiler chickens at poultry farms. Materials and Methods: Broiler chickens at two commercial poultry farms were suspected of being infected with virulent NDV due to high mortality rates. Virus isolated from samples of intestinal tissues, lungs, trachea, spleen, kidneys, and air sacs was adapted in the allantoic cavity of embryonated specific-pathogen-free (SPF) chicken eggs. The NDV pathotype was determined based on the mean death time (MDT) in eggs as well as the intracerebral pathogenicity index (ICPI) and intravenous pathogenicity index pathogenicity indexes of the isolated samples. Broilers were experimentally infected by inoculation with fluids collected from the allantoic cavities of 60 broilers aged 35 days. Serological and molecular tests were followed by enzyme-linked immunosorbent assay to determine levels of anti-NDV immunoglobulin G, and isolates were identified using a hyperimmune (HI) test and real-time polymerase chain reaction (RT-PCR). Results: Suspected and isolated NDV field samples propagated in the allantoic cavity of 10-day-old fertile SPF chickens were NDV positive in the rapid hemagglutination test within a few seconds. Pathogenicity indices and MDT showed that the isolated NDV was viscerotropic and velogenic. The virus was identified as NDV by the HI test using specific anti-LaSota HI serum and RT-PCR with specific primers and probes. Propagation of the virus in the allantoic cavity of embryonated hen eggs produced a viral titer of 109.5 EID50/0.1 mL. Conclusion: The virus isolated from broiler chicken farms in Diyala Province, Iraq, was viscerotropic and velogenic according to the pathogenicity indices and RT-PCR. The isolated NDV caused 100% morbidity and 90% mortality in NDV-vaccinated and experimentally infected broiler chickens.

A broiler poultry farm of six weeks old, vaccinated with LaSota Newcastle disease virus vaccine. The flock was infected with a virulent Newcastle disease virus with mortality rate up to 90%. Newcastle disease virus was isolated from infected birds in embryonated chicken eggs and identified by haemagglutination inhibition test using hyperimmune serum prepared against LaSota viral vaccine. Median Death Time, Intracerebral Pathogenicity Index and Intravenous Pathogenicity Index proved that the virus was a virulent viscerotropic isolate. In experimental infection, broilers were vaccinated twice with LaSota strain, the level of anti-Newcastle disease virus IgG was checked by Enzyme-linked immunosorbent assay test pre and post vaccination and the birds were challenged with the same isolated virulent isolate at 35 days old, the virus was inoculated by oral and nostril routs. The challenge virus produced the same sever clinical signs and the mortality rate reached up to 70%. Tissue samples were collected from intestine, kidneys, lung, trachea, spleen, liver, and the brain of the experimentally infected broilers, they showed sever pathological changes. It seems that vaccination with commercial available vaccine could not produce enough protection against virulent circulating Newcastle disease virus strains, accordingly preparation of viral vaccine from local virulent isolate is recommended after attenuation or inactivation.

The susceptibility of the primary chick embryo chorioallontoic membrane cells to infectious bronchitis virus was evaluated after twenty consecutive passages in chick embryo chorioallontoic membrane cells. Virus replication was monitored by cytopathic observation, indirect immunoperoxidase, and reverse transcription polymerase chain reaction (RT-PCR). At 72 hours post-infection (p.i.) in third passage, the cytopathic effect was characterized by rounding up of cells, monolayer detachment, intracytoplasmic brownish colouration was readily observed by immunoperoxidase from 24 hours p.i in third passage , and at all times the extracted viral RNA from IBV-infected monolayers was demonstrated by RT-PCR. Tissue culture ineffective dose 50 (TCID 50 ) was used to measure virus titration performed on primary chick embryo chorioallontoic membrane cells and the titre in twenty passage was 10 8.6 TCID 50 /ml. The results obtained in this study suggested that the primary chick embryo chorioallontoic membrane cells can be used for adaptation infectious bronchitis virus (IBV) and may be considered a step forward for the use of these cells in the future for IBV vaccine production

Feline coronavirus (FCoV) consists of two biotypes based on their growth in cell culture and their antigenicity. Infections with FCoV are highly prevalent in the cat population worldwide. In this study, Felis catus whole fetus (Fcwf-4)cell culture was infected with FCoV UPM11C/08. Virus multiplication in cell culture was monitored and examined under the transmission electron microscope. The virus particles revealed the characteristic morphology of feline FCoV represented by envelope viruses surrounded by peplomers. Virus attachment and entry into the cell occurred 15 h post-infection (pi), and the myriad of virus particles were observed both extracellularly and intracellularly after 48 h pi. Thereafter, intracellular virus particles were observed to be present in vacuoles or present freely in the cytoplasm.

Feline Coronavirus (FCoV) comprises virulent and avirulent biotypes. While both biotypes can enter the bloodstream of a cat, only the virulent biotypes would replicate in monocytes and macrophages and develop a fatal disease known as Feline Infectious Peritonitis (FIP). In the present study, FCoV viraemia was evaluated in 50 cats consisting of 40 overtly healthy and 10 ill cats suspected of FIP. The blood samples were screened for FCoV genomic RNA by a RT-PCR assay and then followed by a duplex RT-PCR for detection of replicating viral mRNA. In the healthy cats, the virus and its replicating mRNA were detected in 67.5 and 15%, respectively. The later finding suggested that the virus was replicating in a few cats with no clinical sign shown and indicated that FCoV viraemia do not necessarily lead to FIP. Probably the avirulent virus does multiply at low level in the blood or cat can harbor the virulent virus in an early stage of FIP without clinical signs yet. In FIP-suspected cases, all of the ill cats were positive for both FCoV and the replicating viral mRNA suggesting that FCoV could have replicated in blood and produced high amount of the virus and its components which were detectable by the both assays. The duplex RT-PCR assay which has been used to detect the replicating viral mRNA in blood was more specific than the general screening RT-PCR test for the diagnosis of FIP. The RT-PCR results however, should be interpreted in conjunction with other clinical symptoms.

Background Feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) are major causes of morbidity and mortality in domestic and wild felids. Despite the clinical importance of feline retroviruses and the growing interest in cats as pets, information about FeLV and FIV in Malaysia is presently insufficient to properly advise veterinarians and pet owners. A cross-sectional study was carried out from January 2010 to December 2010 to determine the prevalence and risk factors associated with FeLV and FIV among domestic cats in peninsular Malaysia. Plasma samples were harvested from the blood of 368 domestic cats and screened for evidence of FeLV p27 antigen and FIV antibodies, using an immunochromatographic kit. Additionally, data on cat demographics and health were collected using a structured questionnaire, and were evaluated as potential risk factors for FeLV or FIV status. Results Of the 368 cats that were evaluated in this study, 12.2% (45/368; 95% CI = 8.88 - 15.58) were positive for FeLV p27 antigen, 31.3%, (115/368; 95% CI = 26.51 - 35.99) were seropositive to FIV antibodies, and 4.3% (16/368; 95% CI = 2.27 - 6.43) had evidence of both viruses. Factors found to significantly increase the risk for FeLV seropositivity include sex, age, behaviour, sickness, and living in a multi-cat household. Seropositive response to FIV was significantly associated with sex, neuter status, age, behaviour, and health status. Conclusions The present study indicates that FeLV and FIV are common among domestic cats in peninsular Malaysia, and that factors related to cat demographics and health such as age, sex, behaviour, health status and type of household are important predictors for seropositive status to FeLV or FIV in peninsular Malaysia. High prevalence of FeLV or FIV observed in our study is of concern, in view of the immunosuppressive potentials of the two pathogens. Specific measures for control and prevention such as screening and routine vaccination are needed to ensure that FeLV and FIV are controlled in the cat population of peninsular Malaysia.