The ubiquitous flea can host tapeworms, encephalitis, tularemia, and even plague ​ — generally associated with the Black Death, which in just six years wiped out a third or more of the European population during the Middle Ages.
उवा, माइट्‌स व गोचीड यांसारखे लहान कीटक इतर रोगांखेरीज वेगवेगळ्या प्रकारच्या प्रलापक ज्वरांची (टायफस) लागण करू शकतात.