Interaction Between Blood-Sucking Arthropods and Their Hosts, and Its Influence on Vector Potential

Arthropod vectors play a major role in the spread of transmissible infections. Their epidemiological significance is detennined both by internal characteris­ tics of the vector itself, which provide for the development of the pathogens to the infective stage, and by the type of relationship that exists between the vector and the vertebrate host. Until recently, various aspects of transmission of pathogens by insects and acarines had considerably overshadowed the study of these animals as ecto­ parasites. Most work in this field was concerned with arthropods that are harmful to their hosts (1, 7, 18, 31, 71, 73, 96). These studies primarily concerned relationships of arthropods with domesticated animals, ex­ perimental animals, and man. However, data on pathogenicity of ectoparasites and bloodsuckers for wild animals are extremely limited and largely consist of casual observations. Data are much more limited on defense reactions of vertebrates against arthropods; they include various fonns of defensive host behavior against mosquitoes (46), as well as a wide range of immune reactions studied mainly in ticks (116, 117) but also in lice (72) and biting flies (74, 89). Beklemishev (10, 12-14) was the first to analyze in detail the host-parasite relationships between insects, ticks, and mites and the terrestrial vertebrates