Serological evidence of Newcastle disease virus antibodies in wild birds in Zaria, Kaduna State, Nigeria.

Wild birds have been reported to be reservoirs of viral diseases of poultry, and play an epidemiological role in their maintenance and spread. A serological survey was undertaken to determine the evidence of Newcastle disease virus (NDV) antibodies in wild birds in Zaria Kaduna State, Nigeria. A total of 150 apparently healthy wild birds comprising 30 each laughing dove, speckled pigeons, cattle egrets, village weavers and African silver bills were sampled. Sera collected were analysed for the presence of antibodies against NDV and avian paramyxovirus­2 (APMV­2) using the haemagglutination inhibition test. The results showed an overall seroprevalence of 4% (95% CI: 2.05­10.1) to NDV. African silver bill showed a seroprevalence of 10.0% (95% CI: 2.61­24.9) NDV antibodies while seroprevalence of 3.3% (95% CI: 0.16­15.4) was recorded for cattle egrets, village weavers and laughing doves respectively. No statistically significant difference existed for NDV seroprevalence (P>0.05) among the different species of wild birds. All the 150 sera tested negative for APMV­2 antibodies. The result of this study confirmed the exposure of wild birds to NDV in the study area. Continuous surveillance with isolation and characterization of NDV in the wild birds is therefore recommended for strategic planning for control.

Evaluation of a Lateral Flow Assay for Rapid Detection of African Swine Fever Virus in Multiple Sample Types.

Antibody-based lateral flow assay (LFA) is a quick and inexpensive tool used to detect pathogens in field samples, especially in hard-to-reach remote areas that may have limited access to central laboratories during an outbreak or surveillance. In this study, we investigated the ability of a commercially available LFA, PenCheck®, to detect African swine fever virus (ASFV) in clinical samples derived from pigs infected with highly virulent ASFV strains. The assay was specific and positively identified the majority of pigs showing high fever during the early stages (between 3 and 5 days) of infection. PenCheck® LFA also detected ASFV in serum and tissue samples collected from pigs that succumbed to experimental ASFV infection and whole blood, plasma, and tissue samples from the field. The limit of detection of the assay was ASFV titer 107.80 TCID50/mL, corresponding to ASFV real-time PCR values below 23 Ct. Although the sensitivity of the assay is less than that of the laboratory-based real-time PCR assays, the results obtained with the PenCheck® LFA in this study suggest that it can be used as a herd-level, field-deployable, and easy-to-use diagnostic tool to identify ASF-affected farms when access to portable molecular assays or central laboratories is not possible.