Molecular epidemiological insights into Trypanosoma vivax in Argentina: From the endemic Gran Chaco to outbreaks in the Pampas.

Argentina is a home to millions of beef and dairy cattle and is one of the world's major exporters of meat. In the present study, Trypanosoma vivax was prevalent (2016-2018) in two major livestock farming regions, the Gran Chaco and the Pampas. In the Gran Chaco, 29% and 51% of animals (n = 72, taurine x zebuine crossbreed) were, respectively, positive by TviCATL-PCR and the more sensitive fluorescent fragment length barcoding (FFLB) method. While 18.4/38.8% of breeding cows (n = 49) tested positive by PCR/FFLB, infection increased to 52.2/78.3% in an outbreak of acute infection in steers (n = 23, taurine breed) brought from a non-endemic area. In the Pampas, overall infection rates in dairy cows (n = 54, taurine breed) were comparable (p > .01) between PCR (66.7%) and FFLB (62.9%) and showed a remarkable increase (PCR / FFLB) from 48.3/44.8% in 2017 to 88/84% in 2018. Infected dairy cattle exhibited anaemia, fever, anorexia, enlarged lymph nodes, emaciation and neurological signs. In contrast, beef cows (taurine x zebuine crossbreed) from the Pampas (n = 30) were asymptomatic despite exhibiting 16.7% (PCR) and 53.3% (FFLB) infection rates. Microsatellite genotyping revealed a remarkable microheterogeneity, seven genotypes in the Gran Chaco, nine in the Pampas and five shared between both regions, consistent with regular movement of T. vivax infected livestock. Data gathered in our study support the Gran Chaco being an endemic area for T. vivax, whereas the Pampas emerged as an outbreak area of acute infection in dairy cattle with critical negative impact in milk production. To the best of our knowledge, this is the first molecular study of T. vivax in Argentina, and results indicated the need for preventive measures to control T. vivax spread from the Gran Chaco to vast livestock farming areas across Argentina.

Epidemiología de la brucelosis caprina y ovina en la provincia de Formosa, Argentina / Epidemiology of caprine and ovine brucellosis in Formosa province, Argentina

Se realizó un estudio epidemiológico de brucelosis en 516 majadas caprinas o mixtas (caprinos/ovinos) de las 3 regiones agroecológicas de la provincia de Formosa, Argentina. Mediante las pruebas de aglutinación en placa con antígeno tamponado y de fijación del complemento en suero se estudiaron un total de 25.401 caprinos y 2.453 ovinos. Además, se realizaron cultivos bacteriológicos y PCR en muestras de leche de cabras de 3 majadas con brucelosis y abortos recientes. Se detectó brucelosis en 4 de los 9 departamentos de la provincia, la prevalencia global fue del 2 % y la intrapredial varió entre el 1 y el 40%. La proporción de majadas positivas fue del 3,6, el 12 y el 36 % para las regiones este, centro y oeste, respectivamente. Se aisló Brucella melitensis bv. 1 de cabras por primera vez en la provincia. La PCR amplificó fragmentos esperados de 827 pb correspondiente al gen omp2ab (Brucella spp.) y de 731 pb correspondiente al inserto IS711 (B. melitensis). La detección de anticuerpos en ovinos que cohabitan con caprinos sugiere que las infecciones habrían sido causadas por B. melitensis, lo que constituye un riesgo adicional para la salud pública. Los programas de control y erradicación de la brucelosis deberían considerar las majadas mixtas como una sola unidad epidemiológica. Los resultados indican que la brucelosis por B. melitensis bv. 1 es altamente endémica en las regiones centro y oeste de la provincia de Formosa.

An epidemiological study of brucellosis was carried out in 516 goats and mixed flocks (goat/sheep) from the three agro-ecological regions of Formosa province, Argentina. Serum samples from a total of 25401 goats and 2453 sheeps were analyzed using buffered plate agglutination test (BPAT) and complement fixation test (CFT). Bacteriological and PCR analyses on milk samples from goats in three flocks with a history of brucellosis and recent abortions were also performed. Brucellosis was detected in four of the nine departments of the province with an overall prevalence of 2 % and an intra-flock prevalence ranging between 1 % and 40 %. The proportion of infected flocks was 3.6 %, 12 % and 36 % for the eastern, central and western regions, respectively. Brucella melitensis bv. 1 was isolated efrom goats for the first time in the province. The expected fragments of 827 bp from the omp2ab gene (Brucella spp.) and 731 bp from the insert IS711 (B. melitensis) were amplified by PCR. Detection of antibodies by BPAT and FCT in sheep cohabiting with goats suggests that infections could have been caused by B. melitensis, posing an additional risk to public health. Control and eradication programs for brucellosis should consider mixed flocks as a single epidemiological unit. The results indicate that brucellosis by B. melitensis bv1 is highly endemic in the central and western regions of Formosa province.

[Epidemiology of caprine and ovine brucellosis in Formosa province, Argentina]. / Epidemiología de la brucelosis caprina y ovina en la provincia de Formosa, Argentina.

An epidemiological study of brucellosis was carried out in 516 goats and mixed flocks (goat/sheep) from the three agro-ecological regions of Formosa province, Argentina. Serum samples from a total of 25401 goats and 2453 sheeps were analyzed using buffered plate agglutination test (BPAT) and complement fixation test (CFT). Bacteriological and PCR analyses on milk samples from goats in three flocks with a history of brucellosis and recent abortions were also performed. Brucellosis was detected in four of the nine departments of the province with an overall prevalence of 2% and an intra-flock prevalence ranging between 1% and 40%. The proportion of infected flocks was 3.6%, 12% and 36% for the eastern, central and western regions, respectively. Brucella melitensis bv. 1 was isolated efrom goats for the first time in the province. The expected fragments of 827bp from the omp2ab gene (Brucella spp.) and 731bp from the insert IS711 (B. melitensis) were amplified by PCR. Detection of antibodies by BPAT and FCT in sheep cohabiting with goats suggests that infections could have been caused by B. melitensis, posing an additional risk to public health. Control and eradication programs for brucellosis should consider mixed flocks as a single epidemiological unit. The results indicate that brucellosis by B. melitensis bv1 is highly endemic in the central and western regions of Formosa province.

Hidatidosis: estudio epidemiológico en un área de la región oéste de la provincia de Formosa / Hydatidosis: epidemiological study in the eastern region of the province of Formosa

Con el fin de realizar un estudio epidemiológico de la hidatidosis en un área de 1250 Km2 del oeste de la Provincia de Formosa (Argentina), fueron elelgidos al azar 19 establecimientos rurales con 78 poblaciones, 74 perros, 972 caprinos y 2353 vacunos. En el período marzo-septiembre de 1982, sobre 2171 bovinos faenados bajo supervisión veterinaria en el Matadero Municipal de las Lomitas, principal núcleo poblacional del área encuestada, se habían detectado 63(2,9%) bovino con quistes hidatídicos. En esta área la faena domiciliaria de caprinos y la particular convivencia de éstos con el grupo humano y los perros, otorgó especial importancia al estudio del ciclo parasitario del Echinococcus granulosus. Se halló al parásito adulto mediante el uso de bromhidrato de arecolina, en tres de los 74 perros (4,05%) de dos establecimientos (10,53%). La totalidad de los 78 pobladores del área estudiada fueron negativos a la prueba de Doble Difusión Arco 5 (D.D.5) para diagnóstico de hidatidosis

Hidatidosis: estudio epidemiológico en un área de la región oéste de la provincia de Formosa / Hydatidosis: epidemiological study in the eastern region of the province of Formosa

Con el fin de realizar un estudio epidemiológico de la hidatidosis en un área de 1250 Km2 del oeste de la Provincia de Formosa (Argentina), fueron elelgidos al azar 19 establecimientos rurales con 78 poblaciones, 74 perros, 972 caprinos y 2353 vacunos. En el período marzo-septiembre de 1982, sobre 2171 bovinos faenados bajo supervisión veterinaria en el Matadero Municipal de las Lomitas, principal núcleo poblacional del área encuestada, se habían detectado 63(2,9%) bovino con quistes hidatídicos. En esta área la faena domiciliaria de caprinos y la particular convivencia de éstos con el grupo humano y los perros, otorgó especial importancia al estudio del ciclo parasitario del Echinococcus granulosus. Se halló al parásito adulto mediante el uso de bromhidrato de arecolina, en tres de los 74 perros (4,05%) de dos establecimientos (10,53%). La totalidad de los 78 pobladores del área estudiada fueron negativos a la prueba de Doble Difusión Arco 5 (D.D.5) para diagnóstico de hidatidosis (AU)