Human-parasite
Guides
Cimex lectularius
common bed bug, bed bug
Cimex lectularius is a hematophagous ectoparasite in the family Cimicidae, primarily associated with human dwellings. The species has undergone a global resurgence since the late 1990s following decades of suppression by DDT and other insecticides. Populations show documented resistance to multiple insecticide classes including pyrethroids and pyrroles. The species comprises at least two host-associated lineages: one feeding on humans and another on bats.
Pediculus humanus humanus
Human Body Louse, Body Louse
Pediculus humanus humanus is a wingless, dorsoventrally flattened insect that parasitizes humans exclusively. Unlike its sibling subspecies P. h. capitis (head louse), it inhabits clothing and bedding, moving to skin only for blood meals. It serves as the primary vector for epidemic typhus, trench fever, and louse-borne relapsing fever—diseases that have shaped human history, particularly during wars and famines. Genetic studies confirm head and body lice are conspecific, with body lice representing a more recently derived form adapted to clothing.
Pthirus pubis
Crab Louse, Pubic Louse, Crabs
Pthirus pubis is an obligate ectoparasite of humans, the sole species in its genus to infest humans. It is dorsoventrally flattened, wingless, and 1-2 mm in length, with a crab-like appearance due to its broad, short body and specialized clawed legs adapted for grasping coarse human hair. The species has infested humans for approximately 10,000 years, with archaeological evidence from Roman and Medieval Britain, pre-Columbian South America, and southern Peru. Unlike the closely related head and body lice (Pediculus humanus), P. pubis is extremely sedentary, rarely leaving direct contact with the host body, and is transmitted primarily through sexual contact.