Alternate Grazing of Cattle and Horses reduces infections with Strongyle Parasites – a case study

Gastro-Intestinal Nematodes (GIN) impact on the health and the production of horses and cattle, especially regarding young animals.7,10 Mixed and alternate grazing of production animals (herbivores) for the prevention of GIN is an important element of pasture management with the potential benefit arising from the host-selectivity of numerous GIN species.6,9,12 Small ruminants, for example, harbour a number of strongyle parasite species, which will not lead to stable populations in cattle, and in turn, cattle strongyles such as Ostertagia ostertagi or Cooperia oncophora will not reach patency when ingested by sheep. A substantial number of studies have been performed on mixed and alternate grazing between sheep and cattle or goats and cattle and have overall proven its benefit for different climates and environments.1,3,8 Information on the effect of alternate or mixed grazing of cattle with equids is, however, scarce. This is surprising, as with the exception of liver flukes and the strongyle species Trichostrongylus axei and compared to the cattle/small ruminant grazing combination, horses share no GIN species with cattle. Only recently a French study by Forteau et. al. 5 has shown for the first time that mixed grazing of horses and cattle was beneficial for horses in terms of lower strongyle faecal egg counts. No information is, however, available as to whether the horse/cattle grazing combination is also advantageous in terms of reduced GIN infection in cattle

Function of human alveolar macrophages after a 3-day course of azithromycin in healthy volunteers.

Azithromycin (AZM) is a new macrolide antibiotic with a high intracellular/extracellular concentration ratio. Immunomodulatory and antiinflammatory properties have been reported with other macrolides, especially erythromycin. The aim of the present study was to evaluate the effect of AZM on the production of proinflammatory mediators by alveolar macrophages (AM) up to 4 weeks after a 3-day course of AZM (500 mg, once a day). Nineteen non-smoking healthy male subjects were investigated with bronchoscopy and bronchoalveolar lavage. Group 1 received no treatment. Groups 2, 3, and 4 were bronchoscoped 1, 7 and 30 days, respectively, after AZM administration. AZM concentrations were simultaneously measured in plasma and in AM extracts. In serum, AZM levels were higher in group 2 (32.8 +/- 14.2 micrograms/l), at the lower limit of detection in group 3 (2.8 +/- 1.7 micrograms/l), and no longer detectable in group 4. In AM extracts, the highest concentrations were measured in group 2 (51.6 +/- 28.3 ng/microliter) and in group 3 (31.8 +/- 17.2 ng/microliter), and were detected up to 30 days after treatment in group 4 (2.9 +/- 2.3 ng/microliter). There was no significant differences between groups for blood or BAL proinflammatory cytokines levels (TNF-alpha, IL-1 beta, IL-6), and for superoxide generation by AM. We conclude that a 3-day course of AZM 500 mg/day in healthy subjects does not alter the proinflammatory cytokine profile in blood and in AM despite the prolonged tissue impregnation by this drug