Search

Objectives Current recommendations for the control of psoroptic mange in cattle were revised in the face of emerging acaricide resistance. Material and methods The published results of interviews with farmers, multiple field efficacy studies and data simulation were used to revise control strategies for psoroptic mange in cattle. Results Treatment of psoroptic mange relies on the use of acaricides. Available chemical products in Europe are the macrocyclic lactones, flumethrin and in certain countries phoxim. Current recommendations for the control of psoroptic mange comprise of a double treatment, 7 – 10 day interval, with an acaricide at the recommended dose of all affected and in-contact animals after removal of the crusts and shearing of the hair. Multiple studies have reported treatment failure after the use of macrocyclic lactones. This can be caused by suboptimal application of the treatment, as underdosing, wrong interval or formulation or partial treatment of the affected group. In 2012, 54% of the farmers with problems with psoroptic mange in Flanders, Belgium, made at least one of the mistakes. Another underlying cause of treatment failure is acaricide resistance. Results from an efficacy study from 2016-2019 in the study region detected treatment failure on 12 out of 16 farms with macrocyclic lactone resistance as most likely cause. The possible presence or potential development of acaricide resistance increased the need to re-evaluate current control recommendations. It will be essential to identify per farm the acaricides with a normal efficacy, in order to achieve on-farm eradication of the disease. The mite count reduction test (MCRT) is the only available method to measure treatment efficacy in cattle and calculates the reduction in mite counts, based on pre- and post-treatment skin scrapings. A mean reduction in mite counts of ≥95% with a lower limit of the 95%-confidence interval of ≥90% is regarded by the author as normal drug efficacy. When the mean reduction and the lower limit are below their threshold after correct treatment execution, a mite population is classified as resistant. Data simulation has identified the total number of skin scrapings per farm as most important parameter for the diagnostic performance of the MCRT. For the detection of severe reduced drug efficacy (post-treatment mite count reduction

Additional file 1. Clinical appearance and close-up view of Belgian Blue (A, C) and Holstein–Friesian cattle (B, D) infested with Psoroptes ovis at 6 weeks post-infestation, respectively. The yellow circles indicate active lesions on the animals’ skin.

Additional file 3. The width of the epidermis at different time points in Belgian Blue (BB) and Holstein–Friesian (HF) cattle after artificial infestation with Psoroptes ovis (mean and individual values). *p

Additional file 2. Representative histology of skin lesions at 6 weeks post infestation with Psoroptes ovis in Belgian Blue cattle (A: ×100; B: ×400). A: Parakeratosis (filled arrow), dermal oedema and disruption of collagen bundles (dashed line arrows). B: Intercellular oedema, disruption of intercellular bridges and hydeopic degeneration of cells in the epidermis (filled arrows)

The aim of this study was to determine the prevalence and monthly parasitic load of gastrointestinal nematodes and Fasciola hepatica in dairy cattle of the districts Nueve de Julio and Matahuasi el Mantaro Valley (Junín, Peru), as well as the epidemiological factors associated with these parasitosis. Monthly faecal samples were collected from 11 dairy farms in each district for one year. The samples were analysed with the modified Dennis technique for the detection and counting of F. hepatica eggs and the modified McMaster technique for nematode eggs. The mixed logistic regression test was used to evaluate the variables district, time of year, feeding system, age, temperature, rainfall and humidity as possible risk factors. The average monthly prevalence in Matahuasi and Nine of July for gastrointestinal nematodes was 24.5 and 30.3%, with monthly loads of 118.3 and 87.4 hpg, and for F. hepatica of 69.8 and 46.6%, with monthly loads of 7.5 and 3 hpg, respectively. The results indicate that gastrointestinal nematodiasis and hepatic fasciolosis are endemic in the area. The presence of nematodes is significantly associated with the increase in temperature and age, with calves being the most susceptible population, while fascioliasis is related to the increase in temperature and precipitation, and the time of the year, being significantly greater in the dry season. Likewise, a significant relationship was found between the presence of F. hepatica and the district of origin, the risk of infection being significantly higher in Matahuasi., El objetivo del presente estudio fue determinar la prevalencia y carga parasitaria mensual de nematodos gastrointestinales y Fasciola hepatica en bovinos lecheros de los distritos Nueve de Julio y Matahuasi de el Valle del Mantaro (Junín, Perú), así como los factores epidemiológicos asociados a estas parasitosis. Se recolectaron muestras mensuales de heces de 11 establos lecheros de cada distrito durante un año. Las muestras fueron analizadas con la técnica de Dennis modificado para la detección y conteo de huevos de F. hepatica y la técnica McMaster modificada para los huevos de nematodos. Se utilizó la prueba de regresión logística mixta para evaluar las variables distrito, época del año, sistema de alimentación, edad, temperatura, precipitación y humedad como posibles factores de riesgo. La prevalencia promedio mensual en Matahuasi y Nueve de Julio para nematodos gastrointestinales fue de 24.5 y 30.3%, con cargas mensuales de 118.3 y 87.4 hpg, y para F. hepatica de 69.8 y 46.6%, con cargas mensuales de 7.5 y 3 hpg, respectivamente. Los resultados indican que la nematodiasis gastrointestinal y fasciolosis hepática son endémicos en la zona. La presencia de nematodos está significativamente asociado al incremento de temperatura y la edad, siendo las terneras la población más susceptible, mientras que la fasciolasis está relacionada con el incremento de temperatura y precipitación, y la época del año, siendo significativamente mayor en época seca. Así mismo, se encontró una relación significativa entre la presencia de F. hepatica y el distrito de procedencia, siendo el riesgo de infección significativamente mayor en Matahuasi.