BACKGROUND:  Among infectious diseases, Newcastle disease, due to being highly contagious and its rapid spread among poultry and other bird species, is a deadly viral disease and is considered a global threat to the poultry industry. Objectives: To determine the occurrence of Newcastle disease in poultry broiler farms reported to the Iranian veterinary organization during the study period. Methods: This is a cross-sectional study from September 2013 to March 2015. During this study, from 185 farms and a total of 3700 bird sera, cloacal and tracheal swabs were sampled and tested using a haemagglutination inhibition test and reverse transcriptase polymerase chain reaction respectively. Results: In this study, of a total of 185 farms reported to the Iranian Veterinary Organization, 115 farms (62.16%, 95%CI: 55.17-69.14) were positive for Newcastle disease viruses and then using specific primers, 69 farms (37.3%, 95%CI: 30.33-44.26) had vaccinal pathotype (non-acute) and 46 farms (25%, 95%CI: 18.76-31.23) had acute pathotype (field virus). The mean±SD age of infected poultry was 24.63±5.38 days and antibodies titer against Newcastle disease virus was 5.97±1.21. The highest mortality rates were observed in the spring (32.34%) and winter (26.9%), respectively. Mazandaran (37%) and Isfahan (22%) province had the highest percentage of farms with Newcastle disease. Conclusions: The findings of this study suggested virulent Newcastle virus strains are circulating in the Iranian commercial broiler farms in the mentioned time and with high occurrence. Therefore, the relevant authorities need to make correct decisions to reduce the risk of Newcastle disease in the Iranian poultry industry and its control.

BACKGROUND: Serological survey of NDV infection from LBMs would give a good picture of Newcastle disease ecology in a country.OBJECTIVES: This cross-sectional study was carried out to evaluate the seroprevalence of Newcastle disease in live bird markets, bird parks, and zoos in Iran.METHODS: From July to December 2016, blood samples were collected from different bird species in each unit. The serum samples were evaluated via Hemagglutination inhibition test. The seropositive sample was considered a serum with antibody titer 4 or more (1.16) in HI, and units with at least one seropositive bird were considered as the contaminated unit. In this study, the serum samples were taken from various bird species (N=2292) selected from 127 bird markets, bird parks, and zoos distributed in 22 Iranian provinces.RESULTS: Among the 127 sampled units, 70 (55.12 %) were found to be seropositive. In addition, among the 2292 sampled birds, the number of seropositive birds were found to be 495. Among different bird species, the highest sero-positive prevalence belonged to chickens and turkeys with 38.7 % and 32.89 %, respectively.CONCLUSIONS: The results of this study suggested a high prevalence of Newcastle disease in the live bird markets, bird parks, and consequently, across our country. Given the importance of this infectious disease, it is essential to apply appropriate controlling measures, including continuous surveillances of circulating viruses and vaccination programs with conventional vaccines, such as heat-resistant vaccines. On account of the important role of rural poultry and wild birds in Newcastle disease distribution, controlling the disease in rural poultry and continuous surveillance in both can prevent the spread of NDV, particularly to the commercial poultry.

A cross-sectional study was conducted in five provinces and 11 districts of Zambia to determine the seroprevalence of Newcastle disease in Zambian backyard chicken flocks. Of the chickens sampled, 73.9% tested positive for avian paramyxovirus type 1 antibodies by means of an enzyme-linked immunosorbent assay. Seroprevalence varied amongst the five provinces sampled, ranging from 82.6% in the Eastern Province to 48.3% in Luapula Province. Seroprevalence also varied amongst the 11 districts sampled, ranging from 91.3% in Monze district of Southern Province to 22.8% in Mufulira district of the Copperbelt province. Overall, the seroprevalence of Newcastle disease in Zambian backyard chicken flocks has increased since the previous study conducted in 1994.

Two hundred, five-week old chickens were divided into six equal groups (30 chicks/group) and vaccinated with different live NDV vaccines in Nigella sativa oil. The vaccinated birds were bled at one-week interval post-vaccination over six weeks and the collected sera were tested by the HI test. Half of each group was challenged 21-days post-vaccination by intramuscular route of inoculation with 2X105EID50 of the velogenic viscerotropic Newcastle disease virus (VVNDV). Birds were observed for 15 days post-challenge for any clinical signs of Newcastle disease. Deaths within this period were subjected to post mortem examination. The remaining birds in each group were observed after challenge till 42-days post-vaccination.

Ochratoxin A (OTA) is a mycotoxin notably produced by Aspergillus and Penicillium spp. Bacillus subtilis fermentation extract (BSFE) contains specific enzymes which hydrolyse OTA. This study evaluated the efficiency of BSFE in ameliorating the immunotoxic and nephrotoxic effects of OTA in broiler chickens. Day-old broiler chicks were divided equally into four groups of ten: control, OTA (0.5 mg/kg feed), BSFE product (1 mL/L water) and OTA + BSFE at the same concentrations. The chicks were vaccinated against avian influenza, Newcastle disease, and infectious bronchitis, and lymphoproliferation was induced in all birds by phytohaemagglutinin-P (PHA-P). Serum samples were taken before sacrifice and organ tissue samples were taken after, in which renal function biomarkers were assayed and the presence of OTA residue was evaluated by high-performance thin-layer chromatography. Protein markers of apoptosis were determined by qPCR, and tissue lesions were examined histopathologically. Exposure to OTA significantly decreased the antibody response to the vaccines and the lymphoproliferative response to PHA-P, and significantly elevated the renal function indicators: serum urea, uric acid and creatinine. It also induced oxidative stress (reduced catalase activity and glutathione concentration), lipid peroxidation (increased malondialdehyde content), apoptosis (increased Bax and Caspase-3 and decreased Bcl-2 gene levels) and pathological lesions in kidney, bursa of Fabricius, spleen and thymus tissue. Residues of OTA were detected in the serum and tissue. BSFE mitigated most of these toxic effects. BSFE counters OTA-induced immunotoxicity and nephrotoxicity because of its content of carboxypeptidase and protease enzymes.

A field study was conducted to determine the prevalence of various poultry diseases in broilers and layers at Khushab district in Pakistan. The prevalence study was conducted in 360 poultry farms. Diagnosis of diseases in poultry was done based on history, clinical signs, post-mortem examination, cultural, and biochemical characterization. Overall, incidence of Newcastle disease (ND) was found as the highest (avg. 7.85%) in broiler, followed by Fowl typhoid (avg. 6.58%), Mycoplasma (avg. 5.68%), Escherichia coli infection (avg. 5.52%), Coccidiosis (avg. 4.59%), Mycotoxicosis (avg. 4.56%), Infectious Bursal Disease (IBD; avg. 2.84%), Infectious coryza (avg. 2.50%), Hydropericardium syndrome (HPS; avg. 1.67%), and Infectious bronchitis (IB; avg. 1.59%). The period during April to June appeared to be comparatively safer for the broilers as low incidence of disease was recorded at this period. In case of layers, incidence of ND was the highest (avg. 7.92%), followed by Fowl typhoid (avg. 6.97%), Mycotoxicosis (avg. 5.52%), Coccidiosis (avg. 4.75%), IBD (avg. 3.17%), Mycoplasmosis (avg. 3.0%), Infectious coryza (avg. 2.52%), Fowl cholera (avg. 1.52%), IB (avg. 0.90k%), E. coli infection (avg. 0.73%), and HPS (avg. 0.46%). For layers, the period during January to March appeared to be safer. In conclusion, diversified diseases are prevalent in both layers and broilers. Thus, proper vaccination practices, brooding arrangements, preventive measures, and biosecurity practices are recommended.

Experimental intraocular (conjunctival) infection of exotic cockerels with a new field strain of viscerotropic velogenic Newcastle Disease Virus (NDV) was conducted to explore the concurrence of some pathological changes with humoral immune responses. After the NDV infection of 4-week-old cockerels, pathologic changes and antibody responses were observed. The clinical signs observed after the artificial inoculation included inappetence, depression, diarrhea, dyspnea, wing and leg paralysis, torticollis and weight loss. Morbidity due to the NDV was 100%, but mortality was 80% by day 18-21 post-infection. Early hyperthermia followed by terminal hypothermia, decreased packed cell volume (PCV), and 231.4 folds peak-antibody response were observed. Necrotic and/or inflammatory lesions were present in the proventriculus, intestine, liver, spleen, kidney and brain. Neurologic and digestive tract perturbations occurred in 10% and 85% of cases, respectively. The disease consistently caused stunted growth, decreased PCV, and necro-inflammatroy lesions concurrent with antibody response, suggesting probable involvement of immune-mediated mechanisms and cell membrane desialylation by viral neuraminidase in the pathogenesis.

This study was planned to evaluate the extracts of Aloe vera (AV) at three different pH as a growth promoter, immunostimulant and coccidiostat agent in broiler production. This experiment was undertaken for a period of 35 days in the Institute of Animal Sciences, Faculty of Animal Husbandry, University of Agriculture Faisalabad, Pakistan. A total of 150 dayold broiler birds (Cobb) were randomly assigned to 5 treatments with 3 replicates of 10 chicks each. Birds were offered commercial broiler starter and finisher diets supplemented with 100 mg/kg enramycin (ANT), 50 ml/liter AV of pH 3 (AV1), 50 ml/liter AV of pH 7 (AV2), 50 ml/liter AV of pH 12 (AV3) and only fresh clean water (CON).

As animal welfare issue becomes important, the European Union bans conventional cages for laying hens from 2012. So the alternative housing systems like floor pens, aviaries or free range systems have been suggested. From 2011 to 2014, we monitored 20 welfare-oriented laying hen farms in South Korea to figure out serological status of major viral diseases. During this period, total 3,219 blood samples were collected from the randomly selected chickens to test and evaluate the hemagglutination inhibition titers for low pathogenic avian influenza, Newcastle disease and egg drop syndrome' 76. A total of 2,926 blood samples were tested through enzyme linked immunosorbent assay (ELISA) to assess the serological status of infectious bronchitis (IB). The distribution of ELISA titers for IB was various from almost 0 to 20,000 through the all weeks of age. Also, the antibody coefficient of variation for most of the diseases in this study was higher than those of typical cage layers. As this study was the first surveillance for major avian viral diseases of the animal welfare-oriented farms in South Korea, the results obtained from this study will help to determine what information and resources are needed to maintain better biosecurity and to improve the health and welfare of laying hen flocks.

A total of 18 Newcastle disease virus (NDV) isolates that were recovered from 1949 through 1997 were characterized and pathotyped. All viruses were highly virulent as determined by intracerebral pathogenicity indices greater-than or equal to 1.81 in day-old. These pathotypes are typical for viscerotropic velogenic NDV (VVNDV) pathotype viruses. Some differences were observed for the chicken red blood cell elution rate and thermostability of the hemagglutinin at 56℃. Three antigenic groups were identified by a hemagglutination-inhibition assay using NDV monoclonal antibodies. And the predominant gross lesions were as follows: discharge from the nasal cavity, tracheal mucus, petechial hemorrhage in the heart fat, kidney urates and hemorrhage with or without necrosis in the gastrointestinal tract. Severe hemorrhagic or necrotic lesions were also noted in the lymphoid organs and were localized primarily in the spleen and cecal tonsil. However, differences in the occurrence and frequency of the gross lesions were observed between the virus strains. Among them, NDV strains that induced neurological symptoms belonged only to genotype Ⅵ. This strain had spread throughout Korea during the late 1980s to the 1990s, which suggests that specific VVNDVs genotypes might result in neurological symptoms.