Different therapeutic regimes using flubendazole for the treatment of Trichostrongylus tenuis infection in experimentally infected grey partridges Perdix perdix were examined. Flubendazole dosages of 4, 8 and 20 mg/kg were administered orally as a single dose or split into 3 or 9 parts given over 9 days. The efficacy against adult worms in the caeca improved with dose rate. Split doses were at least as effective as single doses, which removed up to 83% of adult T. tenuis. A dose of 20 mg/kg administered on a daily basis over 3 or 9 days gave the best clearance of T. tenuis, resulting in a reduction of at least 95% in worm burden.

Many vector-borne pathogens whose primary vectors are generalists, such as Ixodid ticks, can infect a wide range of host species and are often zoonotic. Understanding their transmission dynamics is important for the development of disease management programmes. Models exist to describe the transmission dynamics of such diseases, but are necessarily simplistic and generally limited by knowledge of vector population dynamics. They are typically deterministic SIR-type models, which predict disease dynamics in a single, non-spatial, closed patch. Here we explore the limitations of such a model of louping-ill virus dynamics by challenging it with novel field data. The model was only partially successful in predicting Ixodes ricinus density and louping-ill virus prevalence at 6 Scottish sites. We extend the existing multi-host model by forming a two-patch model, incorporating the impact of roaming hosts. This demonstrates that host movement may account for some of the discrepancies between the original model and empirical data. We conclude that insights into the dynamics of multi-host vector-borne pathogens can be gained by using a simple two-patch model. Potential improvements to the model, incorporating aspects of spatial and temporal heterogeneity, are outlined.

The statistical aggregation of parasites among hosts is often described empirically by the negative binomial (Poisson-gamma) distribution. Alternatively, the Poisson-lognormal model can be used. This has the advantage that it can be fitted as a generalized linear mixed model, thereby quantifying the sources of aggregation in terms of both fixed and random effects. We give a worked example, assigning aggregation in the distribution of sheep ticks Ixodes ricinus on red grouse Lagopus lagopus scoticus chicks to temporal (year), spatial (altitude and location), brood and individual effects. Apparent aggregation among random individuals in random broods fell 8-fold when spatial and temporal effects had been accounted for.

The role of diet on the growth, survival and movement of red grouse Lagopus lagopus scoticus chicks was examined. We compared two areas of moorland in Scotland: a dry heath with a low density of red grouse and poor chick survival; and a wetter heath/bog with relatively higher red grouse numbers and higher rates of chick survival. There were no differences in clutch size or the proportion of eggs hatching between the two moors but brood survival was significantly lower on the dry heath. Radio-tagged hens with broods were monitored during the first 12 days following hatching; the chicks were captured, weighed and faecal samples collected. Invertebrate samples were collected within brood feeding ranges. Analysis of chick faeces was used to identify dietary components. Heather comprised the major dietary component on both moors. Invertebrates formed a higher component of diet on the wet moor, and this was positively correlated with growth rates, which in turn were positively correlated with chick survival. We present data from an experiment carried out in 1982, in which chicks showed higher growth rates with increasing insect availability. We also show that broods in which all the chicks survived (4–10 days) had smaller home-range areas than broods in which some of the chicks died during this period. We suggest that the differences in chick survival between the two populations were the result of variations in the abundance of invertebrates, particularly tipulids. The protein provided by a high invertebrate component in the diet is, therefore, an important determinant of the growth and survival of young red grouse chicks in some areas.