[Use of the immunoenzyme test ELISA-NS3 to distinguish horses infected by African horsesickness virus from vaccinated horses].

The research aimed to develop a test that could tell the difference between horses that were vaccinated against the African Horsesickness Virus (AHS) and those that are infected with it. Using the protein NS3 as a marker did not work as hoped because the vaccine used did not entirely eliminate this protein.

Background

• African Horsesickness Virus (AHS) is a deadly virus that affects horses, and there is an inactivated vaccine available for it.
• Vaccines are usually designed to simulate an infection, so the immune system generates antibodies that can fight off the actual virus.
• It can be challenging to distinguish between animals that have been vaccinated and those that have been naturally infected because both groups will have antibodies against the virus.
• Scientists were trying to use a protein called NS3, found in the AHS virus, as a marker to tell the difference between vaccinated and infected horses.

Methodology

• The researchers undertook a protocol involving three horses and five repeated injections of inactivated serotype 4 AHS virus.
• They aimed to determine the threshold for the onset of antibodies against NS3.
• An indirect enzyme-linked immunosorbent assay (ELISA), which is a test used to detect and measure antibodies in the blood, was used.
• The recombinant NS3 protein served as an antigen in this test, which is a substance that triggers the immune system to produce antibodies.

Findings

• After multiple injections, horses one and two generated a response to NS3, detected using the ELISA. The third horse did not produce a reaction to NS3.
• These results show that horses receiving the inactivated vaccine can still produce antibodies against NS3, implying the vaccine did not wholly remove this protein.

Implications

• Using NS3 as a marker was thus unhelpful in distinguishing between horses that have been vaccinated and those infected with the virus.
• This study suggests that the vaccine needs to be further purified or refined to entirely eliminate NS3, which could help in the differentiation between vaccinated and infected horses in the future.