In nature, infected and uninfected arthropod vectors often feed together on an animal. In mimicking this scenario in the laboratory, uninfected vectors were found to acquire virus while cofeeding on the same host as infected vectors. However, the vertebrate host on which they fed did not develop detectable levels of virus in its blood. These observations were made with Thogoto virus, an influenza-like virus of medical and veterinary significance. Rhipicephalus appendiculatus ticks were used as the vector and guinea pigs as the vertebrate host. The results demonstrate that a vertebrate that is apparently refractory to infection by an arthropod-borne virus can still play an important role in the epidemiology of the virus, and they suggest a novel mode of arthropod-borne virus transmission.

Objective: To assess whether consumption of 100 ml of whisky or red wine by healthy male subjects increased plasma total phenol content and antioxidant capacity. Design: A Latin square arrangement to eliminate ordering effects whereby, after an overnight fast, nine volunteers consumed 100 ml of red wine, malt whisky or unmatured`new make' spirit. Each volunteer participated on three occasions one week apart, consuming one of the beverages each time. Blood samples were obtained from the anticubital vein at intervals up to 4h after consumption of the beverages when a urine sample was also obtained. Results: Within 30 min of consumption of the wine and whisky, there was a similar and signi®cant increase in plasma total phenol content and antioxidant capacity as determined by the ferric reducing capacity of plasma (FRAP). No changes were observed following consumption of`new make' spirit. Conclusions: Consumption of phenolic-containing alcoholic beverages transiently raises total phenol concentration and enhances the antioxidant capacity of plasma. This is compatible with suggestions that moderate alcohol usage and increased antioxidant intake decrease the risk of coronary heart disease. Sponsorship: Funded by the Scottish Of®ce Agriculture, Environment and Fisheries Department (SOAEFD), the ERASMUS exchange program, the EC-Fair program and the Scotch Whisky Research Institute.

The life-span and fecundity of females of Spodoptera littoralis (Boisd.) of strains that originated from Crete and Egypt were studied in relation to delays in mating. Virgin females and those that were not mated until eight days from emergence lived longest (means of 17 and 18 days, respectively). Earlier matings progressively reduced life-span; those mated at 0 or 1 day lived for averages of only 7·5 to 10·5 days. Preoviposition periods were extended when mating was delayed, from averages of 2 and 3 days, to averages of 9 and 10 days. Both the number of eggs laid and the percentage hatching were reduced by delays in mating beyond a critical period. In the Cretan stock this critical period was two days, but in the Egyptian stock it was less than a day. Cretan females mated early in life laid, on average, 726 eggs each and produced 541 caterpillars. When mating was delayed for four and six days, only 303 eggs were laid per female and only 93 caterpillars hatched. In the Egyptian stock females mated within one day of emergence laid 1208 eggs each and produced 948 caterpillars, compared with 499 eggs and 199 caterpillars for those not mated until six or eight days after emergence. Since a two-day delay in mating reduced the number of caterpillars to between one-fifth and one-tenth of those that resulted from early matings, it would appear that a smaller caterpillar population would result from control methods that reduced the availability of males, either by mass-trapping or blanket-spraying crops with pheromone.

Questing individuals of Ixodes ricinus (L.

The experimental manipulation of separate, but originally identical, populations of Ixodes ricinus (L.) by applying three conventional tick control measures in different enclosures on naturally infested moorland in Wales allowed the elements of the tick-host interaction to be analysed quantitatively and the effectiveness of the control methods to be compared. From the relationship between the sheep stocking density and the numbers of questing ticks picked up by fortnightly blanket-dragging in each enclosure, the death rate of ticks during their activity season and the rate of contact between sheep and ticks were calculated. From this, it was possible to investigate the effect of different stocking densities on the feeding success of ticks. A major factor determining the much lower contact rate for larvae than for nymphs was the different spatial distribution of questing ticks, clumped for larvae and random for nymphs. The non-random use by sheep of the three different vegetation zones in the paddock resulted in the highest contact rate between sheep and ticks in the pasture area, but tick survival was apparently highest in the bog area. Combining these factors resulted in the prediction that the bracken area was the least favourable habitat for ticks. In the two enclosures where the sheep were not treated with acaricide the mean tick loads on the sheep were similar, but the lower overall use of the pasture by the sheep in the low stocking density enclosure (2/ha) resulted in slightly lower tick loads there compared with those in the high stocking density enclosure (4/ha). The numbers of ticks counted in the second year showed that pasture spelling was the most effective control method, acaricide treatment was less effective, and the benefits of halving the stocking density were marginal. The implications of these results for control strategies are discussed.