Rapid and specific detection of avian influenza virus (AIV) is urgently needed due to the concerns over the potential outbreaks of highly pathogenic H5N1 influenza in animals and humans. Aptamers are artificial oligonucleic acids that can bind specific target molecules, and show comparable affinity for target viruses and better thermal stability than monoclonal antibodies. The objective of this research was to use a DNA-aptamer as the specific recognition element in a portable Surface Plasmon Resonance (SPR) biosensor for rapid detection of AIV H5N1 in poultry swab samples. A SPR biosensor was fabricated using selected aptamers that were biotinylated and then immobilized on the sensor gold surface coated with streptavidin via streptavidin-biotin binding. The immobilized aptamers captured AIV H5N1 in a sample solution, which caused an increase in the refraction index (RI). After optimizing the streptavidin and aptamer parameters, the results showed that the RI value was linearly related (R² = 0.99) to the concentration of AIV in the range of 0.128 to 1.28 HAU. Negligible signal ( < 4% of H5N1) was observed from six non-target AIV subtypes. The AIV H5N1 in poultry swab samples with concentrations of 0.128 to 12.8 HAU could be detected using this aptasensor in 1.5 h.

Bacteriophages represent a group of viruses that specifically infect and replicate in bacteria and could potentially be used to reduce recovery of Salmonella from poultry carcasses. Bacteriophages were isolated from municipal wastewater in the presence of Salmonella enteritidis phage type 13A (SE). In the first 2 experiments, commercially processed broiler carcass rinse water was pooled and divided. The addition of 10¹⁰ pfu/mL of a single bacteriophage (PHL 4) with selected concentrations of SE reduced (P < 0.05) frequency of SE recovered as compared with the control rinse water sample. In experiments 3 and 4, broiler carcasses were intentionally inoculated with SE, sprayed with selected concentrations of PHL 4, and rinsed for SE enrichment and isolation. Application of 5.5 mL of 10⁸ or 10¹⁰ pfu/mL of PHL 4 reduced (P < 0.05) the frequency of SE recovery as compared with controls. In experiments 5 and 6, commercially processed turkeys were rinsed with water containing 72 wild-type bacteriophages isolated against SE, which were amplified in SE, or the Salmonella isolated antemortem from drag swabs from the flock selected for in-plant treatment, or a combination of bacteriophages amplified by each bacterial host. All bacteriophage treatments reduced (P < 0.05) frequency of Salmonella recovery as compared with controls. Sufficient concentrations of an appropriate bacteriophage, or a bacteriophage mixture, can significantly reduce recoverable Salmonella from carcass rinses.

Salmonella enterica serovar Enteritidis-lysing bacteriophages isolated from poultry or human sewage sources were used to reduce Salmonella Enteritidis in vitro and in experimentally infected chicks. Cocktails of 4 different bacteriophages obtained from commercial broiler houses (CB4Ø) and 45 bacteriophages from a municipal wastewater treatment plant (WT45Ø) were evaluated. In experiment 1, an in vitro crop assay was conducted with selected bacteriophage concentrations (10⁵ to 10⁹ pfu/mL) to determine ability to reduce Salmonella Enteritidis in the simulated crop environment. Following 2 h at 37°C, CB4Ø or WT45Ø reduced Salmonella Enteritidis recovery by 1.5 or 5 log, respectively, as compared with control. However, CB4Ø did not affect total SE recovery after 6 h, whereas WT45Ø resulted in up to a 6-log reduction of Salmonella Enteritidis. In experiment 2, day-of-hatch chicks were challenged orally with 3 × 10³ cfu/chick Salmonella Enteritidis and treated cloacally with 1 × 10⁹ WT45Ø pfu/chick 1 h postchallenge. One hour later, chicks were treated or not with a commercially available probiotic (Floramax-B11). Both treatments significantly reduced Salmonella Enteritidis recovery from cecal tonsils at 24 h following vent lip application as compared with controls, but no additive effect was observed with the combination of bacteriophages and probiotic. In experiment 3, day-of-hatch chicks were challenged orally with 9 × 10³ cfu/chick Salmonella Enteritidis and treated via oral gavage with 1 × 10⁸ CB4Ø pfu/chick, 1.2 × 10⁸ WT45Ø pfu/chick, or a combination of both, 1 h postchallenge. All treatments significantly reduced Salmonella Enteritidis recovered from cecal tonsils at 24 h as compared with untreated controls, but no significant differences were observed at 48 h following treatment. These data suggest that some bacteriophages can be efficacious in reducing SE colonization in poultry during a short period, but with the bacteriophages and methods presently tested, persistent reductions were not observed.

We evaluated the ability of a commercially available lactic acid bacteria-based probiotic culture (LAB) to reduce Salmonella Enteritidis or Salmonella Typhimurium in day-of-hatch broiler chicks. In these experiments, chicks were challenged with Salmonella Enteritidis or Salmonella Typhimurium and treated with LAB 1-h postchallenge. Following treatment, cecal tonsils and ceca were aseptically collected for Salmonella Enteritidis or Salmonella Typhimurium enrichment or Salmonella Enteritidis enumeration, respectively. In experiments 1 to 3, LAB significantly reduced the incidence of Salmonella Enteritidis (60 to 70% reduction) or Salmonella Typhimurium (89 to 95% reduction) recovered from the cecal tonsils of day-old broiler chicks 24 h following treatment as compared with controls (P < 0.05). Additionally, administration of LAB caused a >2.9 log₁₀ reduction of total cecal Salmonella Enteritidis recovered 24 h following treatment as compared with controls (P < 0.05). In experiments 4 to 7, upon sample enrichment LAB significantly reduced the recovery of Salmonella Enteritidis from the cecal tonsils at 24 h, but not 6 or 12 h posttreatment (P < 0.05). However, in experiments 6 and 7, when total cecal Salmonella Enteritidis recovery was enumerated, a significant treatment-associated reduction was observed 12 h posttreatment, although in cecal tonsil samples there was no difference in Salmonella Enteritidis incidence at 12 h (P < 0.05). In these studies, LAB treatment significantly reduced recovery of Salmonella in day-of-hatch broilers.

Conventionally, bacteriophages are considered viruses capable of amplification only in a narrow range of closely related bacteria. Presently, we sele

Coccidiosis, caused by parasites of the genus Eimeria, is probably the most expensive parasitic disease of poultry. Species of Eimeria are ubiquitous where poultry are raised and are known to cause drastic reductions in performance and induce mortality, thereby affecting the overall health status of poultry. Chemotherapy has been the predominant form of disease control for many years, even though vaccination is steadily gaining importance as a feasible control method. The objective of this review is to highlight recent advancements in understanding the role of host immunity against coccidiosis. In addition, pros and cons associated with chemotherapy and the role of vaccination as an increasingly popular disease control method are discussed. Finally, the role played by recombinant vaccines as a potential vaccination tool is highlighted. With interest growing rapidly in understanding host–parasite biology, recent developments in designing recombinant vaccines and potential epitopes that have shown promise are mentioned.