Recombinant Limosilactobacillus (Lactobacillus) delivering nanobodies against Clostridium perfringens NetB and alpha toxin confers potential protection from necrotic enteritis.

Necrotic enteritis (NE), caused by Clostridium perfringens, is an intestinal disease with devastating economic losses to the poultry industry. NE is a complex disease and predisposing factors that compromise gut integrity are required to facilitate C. perfringens proliferation and toxin production.

Optimal specimen collection and transport methods for the detection of avian influenza virus and Newcastle disease virus.

Background: Active and passive surveillance for avian influenza virus (AIV) and Newcastle disease virus (NDV) is widespread in commercial poultry worldwide, therefore optimization of sample collection and transport would be valuable to achieve the best sensitivity and specificity possible, and to develop the most accurate and efficient testing programs. A H7N2 low pathogenicity (LP) AIV strain was selected and used as an indicator virus because it is present in lower concentrations in swabbings and thus requires greater sensitivity for detection compared to highly pathogenic (HP) AIV. For similar reasons a mesogenic strain of NDV was selected.

H7 avian influenza virus vaccines protect chickens against challenge with antigenically diverse isolates.

Vaccination has been a critical tool in the control of some avian influenza viruses (AIV) and has been used routinely in Pakistan to help control sporadic outbreaks of highly pathogenic (HP) H7 AIV since 1995. During that time, several AIV isolates were utilized as inactivated vaccines with varying degrees of success. In order to evaluate which H7 AIV strains may serve as optimal vaccines for diverse H7 AIVs from Pakistan we conducted vaccination-challenge studies with five H7 vaccines against challenge with two HPAIVs: A/chicken/Murree/NARC-1/1995 H7N3 and A/chicken/Karachi/SPVC-4/2004 H7N3.

Attenuated live vaccine usage affects accurate measures of virus diversity and mutation rates in avian coronavirus infectious bronchitis virus.

The full-length genomes of 11 infectious bronchitis virus (IBV) field isolates from three different types of the virus; Massachusetts (Mass), Connecticut (Conn) and California (CAL) isolated over a 41, 25 and 8 year period respectively, were sequenced and analyzed to determine the mutation rates and level of polymorphisms across the genome. Positive selection was not detected and mutation rates ranged from 10(-4) to 10(-6)substitutions/site/year for Mass and Conn IBV types where attenuated live vaccines are routinely used to control the disease. In contrast, for CAL type viruses, for which no vaccine exists, positive selection was detected and mutation rates were 10 fold higher ranging from 10(-2) to 10(-3)substitutions/site/year.

The pathogenesis of low pathogenicity H7 avian influenza viruses in chickens, ducks and turkeys.

Background: Avian influenza (AI) viruses infect numerous avian species, and low pathogenicity (LP) AI viruses of the H7 subtype are typically reported to produce mild or subclinical infections in both wild aquatic birds and domestic poultry. However relatively little work has been done to compare LPAI viruses from different avian species for their ability to cause disease in domestic poultry under the same conditions. In this study twelve H7 LPAI virus isolates from North America were each evaluated for their comparative pathogenesis in chickens, ducks, and turkeys.

The pathogenesis of H3N8 canine influenza virus in chickens, turkeys and ducks.

Background: Canine influenza virus (CIV) of the H3N8 subtype has emerged in dog populations throughout the United States where it has become endemic in kennels and animal shelters in some regions. It has not previously been determined whether the canine-adapted H3N8 influenza virus can be transmitted to chickens, turkeys or ducks which are economically important animals that are susceptible to type A influenza virus from numerous species.

Methods: Four-week-old specific pathogen-free (SPF) chickens, 3-week-old SPF turkeys and 2-week-old commercial Pekin ducks were inoculated with 10(5·2) 50% tissue culture infectious doses of CIV per bird by the intra-choanal route.

Emergence of a group 3 coronavirus through recombination.

Analyses of turkey coronavirus (TCoV), an enteric disease virus that is highly similar to infectious bronchitis virus (IBV) an upper-respiratory tract disease virus in chickens, were conducted to determine the adaptive potential, and genetic changes associated with emergence of this group 3 coronavirus. Strains of TCoV that were pathogenic in poults and nonpathogenic in chickens did not adapt to cause disease in chickens. Comparative genomics revealed two recombination sites that replaced the spike gene in IBV with an unidentified sequence likely from another coronavirus, resulting in cross-species transmission and a pathogenicity shift.

Infectious bronchitis virus field vaccination coverage and persistence of Arkansas-type viruses in commercial broilers.

To determine the coverage of infectious bronchitis virus (IBV) vaccine field boost in commercial broilers, estimate the relative amount of vaccine virus in the trachea, and follow the clearance of the vaccine, we collected approximately 100 tracheal swabs at various times postvaccination from 10 different flocks and used real-time reverse transcriptase-PCR (RT-PCR) to detect the virus. This allowed us to detect vaccine virus in as few as 3% of the birds in a flock of 20,000 birds with a 95% confidence level. We found that the number of birds positive for IBV vaccine following vaccination in the field resembled a parabolic-shaped curve that peaked around 14 days postvaccination, or it resembled a sinusoidal-type wave with a frequency of about 2 wk.

Avian coronavirus infectious bronchitis attenuated live vaccines undergo selection of subpopulations and mutations following vaccination.

In this study, we were interested in determining if high titered egg adapted modified live infectious bronchitis virus (IBV) vaccines contain spike gene related quasispecies that undergo selection in chickens, following vaccination. We sequenced the spike glycoprotein of 12 IBV vaccines (5 different serotypes from 3 different manufacturers) directly from the vaccine vial, then compared that sequence with reisolated viruses from vaccinated and contact-exposed birds over time. We found differences in the S1 sequence within the same vaccine serotype from different manufacturers, differences in S1 sequence between different vaccine serials from the same manufacturer, and intra-vaccine differences or quasispecies.

Neuroprotection of MPTP-induced toxicity in zebrafish dopaminergic neurons.

Parkinson's disease is characterized by a severe loss of dopaminergic neurons resulting in a range of motor deficits. The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is known to cause a similar loss of dopaminergic neurons in the human midbrain with corresponding Parkinsonian symptoms. Several animal species have also shown sensitivity to MPTP, including primates, mice, goldfish, and, most recently, zebrafish.