Development of improved enzyme-based and lateral flow immunoassays for rapid and accurate serodiagnosis of canine brucellosis

ANALÍA NOVAK; MARÍA E. CORTINA; LUCIANO J. MELLI; SEBASTIÁN ELENA; NATALIA CORBERA; JUAN E. ROMERO; ANA M. NICOLA; JUAN E. UGALDE, ; DIEGO J. COMERCI ; ANDRÉS E. CIOCCHINI.

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias. LIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2017

Brucellosis is a major zoonotic disease caused by Brucella spp. that affects animals and humans. Brucella canis is the etiological agent of canine brucellosis, a disease that can lead to sterility in bitches and dogs causing important economic losses in breeding kennels. The underestimation of the clinical relevance of B. canis coupled with the results of several reports of human brucellosis cases confirmed by isolation of B. canis urge the need to develop new high-performance diagnostic tests that allow an early and accurate diagnosis of canine brucellosis. Here, we aimed to develop and validate enzyme-based (B. canis-iELISA) and lateral flow (B. canis-LFIA) immunoassays for improved serodiagnosis of canine brucellosis using as antigen the B. canis rough lipopolysaccharide (rLPS), obtained by a hot-saline modified method. To validate the assays, 284 serum samples obtained from naturally infected dogs and healthy animals were analyzed. This panel included 71 positive reference samples obtained from dogs in which the infection was confirmed by bacteriological culture and serology (RSAT and AGID positive) and 213 samples obtained from healthy animals with negative serology results. For the B. canis-iELISA (cut-off = 45 8%) and B. canis-LFIA the diagnostic sensitivity was of 98.6%, and the specificity 99.5% and 100%, respectively. These findings demonstrate that both assays have an excellent diagnostic performance. In order to improve the detection and control of the disease and lower the risk of transmission of brucellosis to humans, we propose the implementation of the B. canis-LFIA as a rapid, easy to use screening test in combination with the B. canis-iELISA as a confirmation test. Finally, a blind study including 1,040 serum samples obtained from urban dogs showed a prevalence higher than 5% highlighting the need of performing a more comprehensive serological survey to determine the magnitude of B. canis circulation among the urban dog population in Argentina.