An exploratory investigation of Newcastle disease virus serum antibodies in backyard chickens of Trinidad with geographical considerations

Backyard chickens in rural communities of developing countries provide a potential means for the production of resilient, integrated small poultry farming systems. Despite this, they are often affiliated with the transmission of the economically important Newcastle disease virus (NDV). Presently, in Trinidad, information gaps exist regarding the backyard chicken population. To promote a better understanding of the serological status to NDV in this farming system, 303 unvaccinated backyard chickens from 11 farms across five counties in Trinidad were assessed for the presence of serum NDV antibodies using two commercial enzyme–linked immunosorbent assays (ELISAs). The study also explored the potential application of egg yolk samples for serological testing using a chloroform–free technique. In addition, data on farm locations, demographics, vaccination status, general management and biosecurity practices were obtained using a cross–sectional survey. An association was identified between the ID Screen® Newcastle Disease Conventional Vaccines (NDVS–CV) ELISA and the ID Screen® Newcastle Disease Nucleoprotein Indirect (NDVNP) ELISA (X 2 1 df , P = 0.001). The results indicate the presence of two different NDV antibody types in the serum of unvaccinated backyard chickens across farms in Trinidad. Differences in test seropositivity are suggestive of the influence of geospatial, general management, biosecurity and husbandry factors. These results can provide a useful background in the design of prospective NDV studies that aim at bridging the knowledge gap to promote situational awareness.