前庭刺激对兔听诱发电位和脑电功率谱的影响

本实验观察了正弦旋转方式的前庭刺激对兔听诱发电位和脑电功率谱的影响。结果表明该旋转刺激可导致中枢神经系统抑制.这与运动病时的一些表现十分吻合,提示运动病的发生可能与前庭刺激导致中枢神经系统抑制有关。     

Entry of bluetongue vector Culicoides imicola into livestock premises in Spain

Culicoides imicola Kieffer is considered to be the main vector of bluetongue disease (BT) and African horse sickness (AHS) in the Mediterranean basin. It has been assumed that this midge species is exophilic and, consequently, that stabling of livestock should provide effective protection against these diseases. This study presents the results of sampling surveys for C. imicola carried out both inside and outside stables on three farms in mainland Spain. The number of C. imicola captured varied as a function of the populations sampled and trap location (inside vs. outside). The daily mean number captured inside during the sampling of each farm population was directly correlated with the daily mean number captured outside, but daily correlation of captures was not observed. By contrast with previous studies, the mean catch of C. imicola inside was consistently higher than that outside. No clear effect of stable characteristics on the degree of entry was detected. In addition, proportions of males and age-graded female groups varied among populations and with trap location. Proportionately more males and fewer engorged females were captured outside than inside, although the proportions varied among stables. These results contrast with those of previous studies, and with the assumed pronounced exophilic behaviour of C. imicola , and raise important questions about the vector activity of this species in the study area and its implications for the epidemiology of BT and/or AHS.     

Mycological studies on the equine intestinal tract with particular reference to equine dysautonomia (grass sickness)

A wide variety of non-endophytic fungi was isolated from the stomach, colon and rectum of healthy horses, horses suffering from equine dysautonomia and horses suffering from other disorders clinically resembling dysautonomia. Of the isolates with toxin-producing potential, species of Aspergillus and Penicillium predominated. Absidia spp. occurred in virtually all horses and Rhizopus was very common, but neither is known to produce toxins. The survey did not associate any particular fungal species with equine dysautonomia.     

Spatial and seasonal distribution of Culicoides imicola in Iberia in relation to the transmission of African horse sickness virus

Abstract. Collections of biting midges were made over 24 months from sixty sites spread across Iberia. Information on the distribution of the vector of African horse sickness virus, Culicoides imicola , from these 3119 samples showed that this species was annually present across south-western Spain as far as 3^o53'W and throughout most of Portugal, up to 41^o5'N. C.imicola was found in all areas where African horse sickness epizootics had occurred in 1987-90 and also in areas outside the epizootic zones.
Seasonal patterns of capture success of C.imicola , from seventeen frequently sampled sites where the vector was present, usually showed a late summer-early autumn peak. At the sites furthest south there was a discrete peak, mostly in September or October, before and after which the numbers captured increased or decreased steadily. At higher latitudes peak abundances occurred as early as May or as late as November, population build up was less uniform and numbers often declined rapidly after the peak was reached. Both the distribution and seasonal abundance patterns closely matched transmission patterns of African horse sickness virus, which rose during late summer and caused most cases during the autumn months.