Comparative study of agar gel immunodiffusion (AGID) protocols for the diagnosis of equine infectious anemia in Brazil Estudo comparativo de protocolos de imunodifusão em gel de ágar para o diagnóstico da anemia infecciosa equina no Brasil

To evaluate the Equine Infectious Anemia (EIA) agar gel immunodiffusion (AGID) protocols, two different kits commercially available in Brazil were used: an imported kit (kit A) and a domestically produced kit (kit B). Kit A was submitted to the protocols recommended by the World Organization for Animal Health (OIE) and the protocol recommended by the Ministério da Agricultura Pecuária e Abastecimento (MAPA). Kit B, the Brazilian kit, was submitted only to the MAPA-recommended protocol and was used as a reference in this study. A total of 345 equid serum samples, including eld samples, serum sets from of cial laboratories and a weak positive serum control from National Veterinary Services Laboratories (NVSL, USA), were used. Parameters such as the sensitivity of kit A in the two protocols, the detection limit of kits and the occurrence of nonspeci c reactions or nonidentity were evaluated. When Kit A was used for an AGID procedure performed according to the OIErecommended protocol, the kit demonstrated good agreement with kit B and 99 % relative sensitivity. However, when kit A was processed according to the MAPA-recommended protocol, it failed to detect 1.16 % of weak positive samples and its relative sensitivity decreased to 96 %. The detection limit of kit A was lower than the detection limit of kit B for weak positive samples in both protocols. The occurrence of non-identity reactions was higher with kit B than with kit A. The training of veterinarians to ensure the correct execution of the AGID test protocol should be intensi ed in Brazil.