Control of Haematobia irritans and Stomoxys calcitrans with Metarhizium anisopliae in naturally infested cattle / Control de Haematobia irritans y Stomoxys calcitrans con Metarhizium anisopliae en ganado naturalmente infestado

ABSTRACT Objective. Assess the efficacy of Metarhizium anisopliae strain 135 (Ma135) applied by aspersion to reduce simultaneous infestation of Haematobia irritans and Stomoxys calcitrans in naturally infested cattle maintained in a production system which combine grazing and confinement in pens. Materials and methods. Was applied an aqueous formulation of Ma135 (1x108 conidia/ml) on a nine cows group in six occasions with seven days interval, while the control group received the same formulation without conidial content. The infestation index was estimated daily for each fly independently; the effectiveness of the formulation was calculated using the Abbott's formula. Results. The Ma135 formulation had a reduction in the fly population of 58% for H. irritans and 69% for S. calcitrans, taking into consideration the six study weeks, in addition to causing no negative effects on animal health. An Infestation index reduction was observed from the first week post-treatment (p<0.05) and maintained this trend throughout the study. Conclusions. The present study has demonstrated the potential of strain Ma135 to reduce the simultaneous infestation of both hematophagous flies in cattle under conditions of natural infestation.

RESUMEN Objetivo. Evaluar la eficacia de la cepa 135 de Metarhizium anisopliae (Ma135) aplicada por aspersión para reducir la infestación simultánea de Haematobia irritans y Stomoxys calcitrans en ganado naturalmente infestado mantenido en un sistema de producción de leche que combina el pastoreo y el confinamiento en corrales. Materiales y métodos. Se aplicó una formulación acuosa de Ma135 (1x108 conidios/ml) a un grupo de nueve vacas en seis ocasiones con un intervalo de siete días, mientras que el grupo control recibió una solución compuesta por agua, Monooleato de polioxietileno sorbitán en solución 0.01% y un adyuvante agrícola al 0.1%. Se estimó diariamente el índice de infestación para cada mosca de forma independiente; la efectividad de la formulación se calculó usando la fórmula de Abbott. Resultados. La formulación de Ma135 tuvo una eficacia en el control de la infestación de 58% para el caso de H. irritans y de 69% para S. calcitrans, tomando en cuenta las seis semanas de estudio, además de que no causó ningún efecto negativo en la salud de los animales. La reducción del índice de infestación se observó desde la primera semana post-tratamiento (p<0.05) y mantuvo esta tendencia durante todo el estudio. Conclusiones. El presente estudio ha demostrado el potencial de la cepa Ma135 para reducir la infestación simultánea de ambas moscas hematófagas en el ganado bajo condiciones de infestación natural.

Infección por Neospora caninum en ganado de carne mantenido en condiciones de pastoreo en el centro-norte de México / Neospora caninum infection in beef cattle reared under grazing conditions in north-central Mexico

Objetive. To determine the seroprevalence of N. caninum antibodies and prevalence of parasite DNA in blood, and estimate the association between seroprevalence and the potential risk of some factors in beef cattle under grazing conditions in north-central Mexico. Materials and methods. Blood samples from 139 cows and only 10 bulls belonging to 13 farms were collected and evaluated by ELISA test to detect antibodies against N. caninum. Furthermore, to determine the presence of parasite DNA, nested PCR probe was performed on blood samples. Association between potential risk factors and seroprevalence was estimated. Results. Overall seroprevalence was 23% (35/149 samples), while the prevalence of parasite DNA in blood was 28% (42/149 samples). Of the 149 animals examined 28 (19%) were positive to both tests (25 cows and 3 bulls). Concordance between tests was k = 0.63. All herds had seropositive animals with positive parasite DNA detection in blood. The only risk factor identified was the presence of dogs (OR= 2.65). Conclusions. This study showed that bovine neospososis should be considered as an important infectious disease in north-central Mexico herds. Therefore, an epidemiological control should be taken into consideration to avoid the negative effect of this disease on mexican beef industry.

Neospora caninum: Detección de ADN en sangre durante la primera gestación de vaquillas infectadas naturalmente / Neospora caninum: DNA detection in blood during first gestation of naturally infected heifers

The aim of the study was to detect the DNA presence of N. caninum in naturally infected animals, at two moments of their first gestation and at parturition, as well as to record the presentation of abortions. Twenty females between 12 to 14 months of age, seropositive to ELISA test, were selected from a dairy farm with presence of this parasitosis. The females were artificially inseminated and blood samples were taken in the first and second third of gestation and during parturition; DNA was isolated and it was analyzed by a single tube nested PCR with specific primers. In the sampling corresponding to the first third of gestation, 7/20 positive cases were observed (35%), in the second 15/20 (75%) and during parturition 10/20 positive cases (50%). From the total of the animals included in this study, three stayed negative to the test in the three samplings (15%), four were always positive (20%), eight were positive in the second sampling but negative in first (40%) and five were positive in the second and negative in first and the third sampling (25%). All animals remained seropositive during the study; four aborted in the last third of gestation. All the live born calves were seropositive to N. caninum.

El objetivo del trabajo fue detectar la presencia de ADN de N. caninum en animales infectados naturalmente, en dos tiempos de su primera gestación y al parto, así como registrar la presentación de abortos. Se seleccionó, en un establo, con presencia de parasitosis, un lote de 20 hembras de entre 12 y 14 meses de edad, seropositivas en ELISA, las hembras fueron inseminadas artificialmente y se tomaron muestras de sangre en el primero y segundo tercios de gestación y al parto; se aisló ADN y se sometió a PCR anidado en un solo tubo con iniciadores específicos. En el muestreo correspondiente al primer tercio de la gestación, se observaron 7/20 casos positivos (35%), en el segundo 15/20 (75%) y al parto 10/20 casos positivos (50%). De los animales incluidos en el estudio, tres se mantuvieron negativos a la prueba en los tres muestreos (15%), cuatro fueron siempre positivos (20%), ocho fueron positivos en el segundo muestreo pero negativos en el primero (40%) y cinco fueron positivos en el segundo y negativos en el primero y tercero muestreos (25%). No se presentó seroconversión en ningún animal durante el estudio; cuatro de ellos presentaron aborto en el último tercio de gestación. Todas las crías nacidas vivas resultaron seropositivas a N. caninum.