The prevalence of 'Culicoides', the parasitic vectors of Blue tongue, in Malta

Abstract

Following the first year, at the Institute of Agriculture, University of Malta, we had credits on Enthemology and Agricultural Zoology with Dr. Antoine Vella. This made me very interested in such subjects. Having been in contact with some form of entomological practice at work, I became interested in carrying out this study, using the knowledge I acquired from such lectures on this current theme, as well as applying the practical work, I've learnt at the Istituto Zooprofilatico di Teramo, Italy. In 2002 local livestock were monitored for the virus causing bluetongue disease, through a serological survey and two bovines from the total of animals tested gave a positive result. This may have shown that our local herd was in the range of BT transmitting insects. This study was carried out to catch & identify any popular vectors of BT ( Culicoides spp) and to notify which particular Culicoides spp which might have been the actual transmitters in our islands. In this enthemological survey, a number of special light traps were used. The trap sites were positioned at some localities in Malta & Gozo. These served as the sources of insect catch, from which such samples would then be examined in the lab. On special sample forms, details of farmers and location were taken respectively. Such samples were cleaned from debris and examined with special equipment in the lab, observing the wing patterns and other morphological features. The four main species of Culicoides, I was to look for were most importantly, C.imicola & C.pulicaris. Culicoides imicola is a major known transmitter of BT disease, and it was the main target, apart from other novel vectors. (Gioffredo, M) quoted that: "C.Paulae bormann is a commonly found species, in Malta but no evidence shows that it is a vector of Blue Tongue. "This strongly indicated that there should be the prevalence of some vector species, which might have our animals at risk, if they come in contact. So sampling was carried out to look for potential vectors.