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Abstract Backgroud Anaplasma phagocytophilum (formerly Ehrlichia phagocytophila) causes the disease tick-borne fever (TBF) in domestic ruminants and has for decades been one of the main scourges for the sheep industry in the coastal areas of Norway. Current control strategies are based on reduction of tick infestation by chemical acaricides. Methods In the present study, we investigated if frequent pour-on applications of pyrethroids would reduce tick infestion rate and seroprevalence of A. phagocytophilum infection in sheep. Forty lambs, one month old, of the Norwegian White Sheep breed were used. The lambs belonged to the experimental sheep flock at the Department of Production Animal Clinical Sciences. None of the lambs had been on I. ricinus infested pasture before turnout (day 0). All lambs were twins and twenty lambs were treated with a pour-on pyrethroid (Bayticol®, Bayer A/S, DK-2300) with a dose of 5 ml on days 0, 14, 28, 42, 56, 70, 84, 98, 112 and 128. Twenty lambs were untreated controls. The lambs were collected every fourteen days on pasture for treatment. In addition, the lambs were examined for ticks, blood sampled, weighed, and rectal temperature was recorded. Results and conclusion A significant reduction in tick infestion rate was detected on treated lambs. However, the present results indicate that frequent acaricide treatment does not reduce the seroprevalence to A. phagocytophilum on tick-infested pasture.

Abstract Background Dairy cattle were used as sentinels for the presence of Leptospira infection in Swedish livestock in four regions contrasting in precipitation and temperature during the summer time. The aim of the study was to estimate the prevalence of five serovars of Leptospira of low pathogenicity in dairy cattle in these four regions. Findings Around 150 blood samples were collected from five dairy farms from each region, making 610 samples in total, during December 2009. The samples were screened for L. kirschneri sv Grippotyphosa, L. interrogans sv Icterohaemorrhagiae, L. interrogans sv Canicola, L. borgpetersenii sv Sejroe and one domestic strain similar to sv Sejroe, called strain Mouse 2A using the Microscopic Agglutination Test. Six animals (1%) were seropositive for the strain Mouse 2A. Four of the positive samples were from the south-west region which also was the region with highest precipitation. There were no positive samples to any of the other serovars studied. Conclusions The present data indicate that there is a low seroprevalence of Leptospira in Swedish dairy cows. These findings can be used as baseline data to investigate the effects of, for instance, climatic change or alterations in wildlife reservoir populations on the seroprevalence of Leptospira in the future.