Brotes de babesiosis y anaplasmosis bovina diagnosticados en el INTA Salta, Argentina: período 2006-2016

Se realizó un estudio retrospectivo de brotes de babesiosis y anaplasmosis (tristeza parasitaria bovina, TPB) ocurridos entre 2006 y 2016 en el Noroeste argentino (NOA) para evaluar algunos aspectos epidemiológicos y clínicos de estas enfermedades. De 4.398 muestras para diagnóstico, 238 (5,4%) tuvieron sospechas de TPB, las cuales se confirmaron en 106 (44,3%) casos por observación microscópica de los agentes causales. Cuarenta y siete (44,3%) brotes se debieron a Anaplasma marginale, 40 (37,7%) a Babesia bovis y 14 (13,2%) a Babesia bigemina. En cinco (4,7%) focos de babesiosis no se determinó la especie causal de Babesia. Los brotes se diagnosticaron en 62 establecimientos ganaderos de cuatro provincias (Salta, Jujuy, Santiago del Estero y Chaco). La mayoría ocurrieron en verano y otoño, con máxima incidencia en abril y nula en setiembre para ambas noxas. Las vacas adultas fueron la categoría de ganado más afectada. En 58% (61/106) de los brotes murió al menos un bovino, con un número promedio de cuatro muertes por brote. Se concluye que la TPB continúa incidiendo negativamente en la producción bovina del NOA. SUMMARY. Bovine babesiosis and anaplasmosis outbreaks diagnosed at INTA Salta, Argentina: 2006-2016. A retrospective study of babesiosis and anaplasmosis outbreaks (tick fever, TF) was made, which occurred from 2006 to 2016 in Northwest Argentina (NWA), to evaluate clinical and epidemiological aspects of these diseases. From 4,398 specimens, 238 (5.4%) were associated with suspicions of TF and 106 of these cases (44.3%) were confirmed as TF outbreaks by microscopic observation of causal agents. Forty seven (44.3%) were due to Anaplasma marginale, 40 (37.7%) to Babesia bovis and 14 (13.2%) to Babesia bigemina. In five (4.7%) outbreaks of babesiosis, Babesia species were not determined. Outbreaks were diagnosed at 62 different cattle ranches in four provinces (Salta, Jujuy, Santiago del Estero and Chaco). The outbreaks occurred mostly during summer and autumn with a peak of incidence in April and null incidence in September for both diseases. Adult cows were the most affected cattle category. At least one death was recorded in 58% (61/106) of the outbreaks and the average number of deaths was determined as four by outbreak. We conclude that TF maintain its negative historical impact on cattle production of NWA.