Salivary Secretions of Blood-sucking Insects in Relation to Blood Coagulation

Abstract

MOST blood-sucking insects at the time of biting inject into their host an irritant which causes a skin reaction, generally a wheal, more or less conspicuous and itching in relation to the habituation of the host to the particular parasite. Although these injections are of such great importance in the transmission of disease, their purpose has in no ease been properly elucidated hitherto. Macloskie forty years ago suggested that the salivary secretion of mosquitoes prevents the blood from clotting on the way to the stomach, but the work of Nuttall and Shipley (1903), and of Schaudinn (1904), threw doubt on this theory. Cornwall and Patton (1914) proved the presence of an anticoagulin in the salivary glands of several bloodsucking insects and ticks, and also showed that a neutralising coagulant enzyme sometimes existed in the stomach.