Epidemiology of bovine brucellosis in Costa Rica: Lessons learned from failures in the control of the disease

Abstract

Brucellosis, caused by Brucella abortus is a major disease of cattle and a zoonosis. In order to estimate the bovine brucellosis prevalence in Costa Rica (CR), a total 765 herds (13078 bovines) from six regions of CR were randomly sampled during 2012–2013. A non-random sample of 7907 herds (532199 bovines) of the six regions, arriving for diagnoses during 2014–2016 to the Costa Rican Animal Health Service was also studied. The prevalence estimated by Rose Bengal test (RBT) ranged from 10.5%-11.4%; alternatively, the prevalence estimated by testing the RBT positives in iELISA, ranged from 4.1%-6.0%, respectively. However, cattle in CR are not vaccinated with B. abortus S19 but with RB51 (vaccination coverage close to 11%), and under these conditions the RBT displays 99% specificity and 99% sensitivity. Therefore, the RBT herd depicted in the random analysis stands as a feasible assessment and then, the recommended value in case of planning an eradication program in CR. Studies of three decades reveled that bovine brucellosis prevalence has increased in CR. B. abortus was identified by biochemical and molecular studies as the etiological agent of bovine brucellosis. Multiple locus variable-number tandem repeat analysis-16 revealed four B. abortus clusters. Cluster one and three are intertwined with isolates from other countries, while clusters two and four have only representatives from CR. Cluster one is widely distributed in all regions of the country and may be the primary B. abortus source. The other clusters seem to be restricted to specific areas in CR. The implications of our findings, in relation to the control of the disease in CR, are critically discussed.

Persistence of Brucella abortus lineages revealed by genomic characterization and phylodynamic analysis

“…Brucellosis became a notifiable disease in CR in 1915, after the first isolation of "Bang´s bacillus" from the blood of a human patient [15,16]. More recently, and thanks to improved surveillance and diagnosis of the disease by public health authorities [8], an increasing number of human cases have been reported, with positive hemocultures and description of the first human cases caused by Brucella neotomae [17,18].…”

“…In a previous study, focused on prevalence and molecular epidemiology of B. abortus in bovines from CR, we showed that the isolates clustered in four discrete groups using Multiple-Locus Variable Number Tandem Repeat Analysis of 16 loci (MLVA-16). This suggested at least four different introductions of the bacterium into CR [8]. To gain insights on the phylodynamics of B. abortus introductions, we characterized a total of 188 B. abortus isolates from CR recovered from bovines and humans from 2003 to 2018, by MLVA and 95 of them by whole genome sequencing (WGS).…”

“…Socioeconomically, the country is divided in six regions: Northern, Central, Brunca, Chorotega, Caribbean Huetar and Central Pacific [7]; the Northern and Central regions are the main livestock farming areas. The only prevalent Brucella species in domestic livestock of CR is Brucella abortus, with a seroprevalence in cattle close to 11% and to 21.7% in water buffalo farms [8,9]. No information of brucellosis in CR terrestrial wildlife is available.…”

Proyectos interuniversitarios y multidisciplinarios relacionados con el patógeno zoonótico Brucella abortus realizados en el CIB

“…El protocolo de identificación generado permitió identificar, como B. abortus, B. canis y B. ceti, aislamientos de Brucella existentes en las universidades públicas. Los aislamientos de B. ceti provenían del Pacífico costarricense y representaron un nuevo genotipo a nivel mundial que no se había reportado antes [11]. El protocolo de identificación fue transferido a SENASA.…”

Aspectos epidemiológicos de la brucelosis en humanos en las Áreas Rectoras Aguas Zarcas y Los Chiles, Costa Rica, 2015-2017

“…Este factor contribuye, fuertemente, al silencio epidemiológico que ha caracterizado a las zoonosis, aún en zonas endémicas. Sin embargo, en países como México, se han incrementado los casos por el aumento en el reporte y sistemas de notificación(Cárdenas 2000).Así, los hallazgos de este estudio, de una seroprevalencia que supera el 10%, a pesar de ser en población de un riesgo aumentado por su exposición a los bovinos y sus secreciones, debe alertar, al menos en estas Áreas Rectoras de Salud que, dado que la enfermedad se puede confundir con muchas otras enfermedades febriles y que, por estar en una zona ganadera endémica a brucelosis(Hernández-Mora et al 2017), esta enfermedad debe ser tomada en consideración, con mucho mayor frecuencia y diligencia,…”