Anoplura

Anoplura, commonly known as sucking lice, is a suborder of lice within the order Phthiraptera. They are obligate ectoparasites of mammals that feed exclusively on blood, using piercing-sucking mouthparts. They are small, dorsoventrally flattened, wingless insects with strong claws adapted for clinging to hair and skin.

Taxonomy and biology: Anoplura includes species that parasitize a wide range of mammals, including humans. In humans, the best known representatives are Pediculus humanus capitis (head louse), Pediculus humanus humanus (body louse), and Pthirus pubis (pubic louse). Compared with chewing lice, anoplurans have mouthparts suited for blood feeding and generally show a more robust association with their host’s skin and hair.

Life cycle: Eggs, or nits, are cemented to hair shafts. The nits hatch into nymphs, which undergo three molts before reaching the adult stage. All life stages feed on the host’s blood. Adults typically live for several weeks to a couple of months, depending on environmental conditions and access to a host.

Hosts, transmission, and health impact: Anopluran lice are adapted to specific mammalian hosts and are transmitted mainly through close contact, shared bedding or clothing, and, in some settings, fomites such as combs. Infestations cause itching and dermatitis; heavy infestations can contribute to anemia. Some body lice are vectors of pathogens, notably Rickettsia prowazekii (epidemic typhus), Borrelia recurrentis (relapsing fever), and Bartonella quintana (trench fever). Pubic and head lice are generally not major disease vectors, but they are a common public health concern due to irritation and social stigma.

Diagnosis and control: Diagnosis is by visual inspection for lice or nit eggs on hair or clothing. Treatment relies on topical pediculicides (such as permethrin or pyrethroids), manual removal with a fine comb, and thorough cleaning of clothing, bedding, and environment. Close contacts are often advised to be treated concurrently.