MODULE 9: Order Siphonaptera (Fleas) and Phthiraptera (Lice)

Order Siphonaptera

Fleas or pulgas, derived from Greek siphon meaning tube or pipe and aptera meaning wingless, secondarily wingless insects with piercing and blood-sucking mouthparts, about 2,500 species, external parasites of mammals and birds, survive through hematophagy

General Characteristics of Fleas

Wingless with laterally compressed bodies, thick dark-brown glossy chitinous covering, compound eyes absent but some have simple eyes, abdomen has 10 segments, 9th segment bears sensory plate called sensilium or pygidium covered by sensory setae, tergum of 9th abdominal segment forms claspers, chitinous coiled penis or aedeagus, third leg pair longer and adapted for leaping, head may bear dark spines called combs or ctenidia, antennae are 3-segmented and club-shaped in a groove behind the simple eye, mandibles are cutting structures, not markedly host-specific

Echidnophaga gallinacea

Stick-tight flea, affects chickens in the southeastern United States, angular head, no ctenidia, may also attack horses, cattle, dogs, rats, and other hosts

Tunga penetrans

Chigoe flea or jigger, primarily affects humans but may attack pigs, rats, skunks, and others, thorax reduced, frons sharply angled or angular

Pulex irritans

Human flea, affects humans and other mammals, genal and pronotal ctenidia absent, mesopleural rod absent, frons smoothly rounded

Xenopsylla cheopis

Oriental rat flea, occurs on brown and black rats but readily bites humans, frons smoothly rounded, mesopleural rod present, genal and pronotal ctenidia absent

Ctenocephalides felis felis

Cat flea, oral and pronotal ctenidia present, frons pointed, first spine of oral/genal ctenidia about as long as the second, head elongated, most common flea species in dogs and cats

Ctenocephalides canis

Dog flea, less common than C. felis, occurs in dogs and cats, first spine about half as long as the second, head rounded

Ceratophyllus fasciatus

Northern rat flea, present in the Philippines, occurs in rodents, oral and pronotal ctenidia present

Ceratophyllus gallinae

Occurs in chickens

Ceratophyllus niger

Occurs in chickens

Leptopsylla cuniculi

Rabbit flea

Leptopsylla segnis

Mouse flea, characterized by the presence of vertical genal ctenidia

Flea Life Cycle

Female lays up to 20 eggs at a time and about 400–500 eggs during her lifetime, eggs deposited in dust, dirt, or dried fecal matter, eggs hatch in 2–16 days with an average of 7–9 days, larvae are slender, 13-segmented, yellowish-white, with long bristles and chewing mouthparts, feed on dried blood, feces, and organic matter, last abdominal segment bears two hooked processes called anal struts used for locomotion and holding onto surfaces, pupation occurs after 7–10 days, adult emerges

Flea Life Span

Life cycle takes 3–6 weeks, lifespan without food is 1–4 months, lifespan with food is 3–34 months

Direct Pathogenic Effects of Fleas

Allergic flea-bite dermatitis or chronic nonspecific dermatitis, irritation and wounds from scratching, Tunga penetrans causes foot ulceration and subsequent bacterial infection, Echidnophaga gallinacea burrows deeply into chicken skin and may cause nodules and ulcers on the comb, wattles, and around the eyes

Fleas as Mechanical Transmitters

Xenopsylla cheopis transmits bubonic plague (Yersinia pestis) and typhus (Rickettsia typhi), Leptopsylla cuniculi transmits myxomatosis in rabbits

Fleas as Intermediate Hosts

Ctenocephalides felis, C. canis, and Pulex irritans – Dipylidium caninum of dogs, cats, and humans, C. canis and C. felis – Dipetalonema reconditum, Ceratophyllus fasciatus and Xenopsylla cheopis – Hymenolepis diminuta, C. canis, P. irritans, and X. cheopis – Hymenolepis nana, C. fasciatus – Trypanosoma lewisi

Flea Treatment and Control

Give corticosteroids as palliative treatment if flea-bite allergy causes severe distress, apply insecticides to hosts and surroundings, burn litter and debris, maintain cleanliness

Order Phthiraptera

Lice, dorsoventrally flattened and wingless, most are blind while a few have primitive photosensitive eyes, legs terminate in claws, mammalian lice have 1 claw and bird lice have 2 claws, permanent ectoparasites that usually cannot survive away from the host for more than a day or two, head, thorax, and abdomen distinct, incomplete metamorphosis, entire life cycle spent on the host

Two Suborders of Phthiraptera

Anoplura – sucking lice, Mallophaga – biting lice

Anoplura vs. Mallophaga: Head

Anoplura – usually pointed anteriorly, Mallophaga – broader than thorax

Anoplura vs. Mallophaga: Mouthparts

Anoplura – sucking, blood contained in the haustellum, Mallophaga – biting or chewing

Anoplura vs. Mallophaga: Food Source

Anoplura – blood and tissue fluids, Mallophaga – epithelial debris, dried blood, and serum

Anoplura vs. Mallophaga: Eyes

Anoplura – eyes present in Pediculidae, Mallophaga – vestigial

Anoplura vs. Mallophaga: Number of Claws

Anoplura – 1 claw aided by a tibial spur or tibial pad, Mallophaga – 1 or 2 claws

Anoplura vs. Mallophaga: Hosts

Anoplura – mammals only, Mallophaga – mammals and birds

Anoplura vs. Mallophaga: Thorax

Anoplura – small, all segments fused, Mallophaga – indistinctly segmented, mesothorax and metathorax fused

Anoplura vs. Mallophaga: Paratergal Plate

Anoplura – present, Mallophaga – absent

Anoplura vs. Mallophaga: Antennae

Anoplura – readily visible at sides of head, Mallophaga – may or may not be visible at head sides

Anoplura vs. Mallophaga: Host and Site Specificity

Anoplura – not highly site-specific, Mallophaga – highly site-specific

Habits of Anoplura

Slow-moving but powerful legs, attach eggs individually to host hairs or, in human body lice, clothing fibers, have 3 nymphal stages that live and feed like adults, all stages feed on host blood, maintain host contact through relatively simple responses, Pediculus and Haematopinus respond to warmth and smell, thigmotactic and move less on rough surfaces, negatively phototactic and move toward dark objects, live at relatively high temperatures but leave hosts when temperature becomes too high, such as during fever, and transfer to another host

Important Families of Anoplura

Haematopinidae, Linognathidae, Pediculidae

Anoplura Family Differences: Paratergal Plates

Haematopinidae – marked, Linognathidae – absent, Pediculidae – present

Anoplura Family Differences: Leg Pairs

Haematopinidae – similar sizes, Linognathidae – first pair smallest, Pediculidae – similar sizes

Anoplura Family Differences: Temporal Angles

Haematopinidae – present, Linognathidae – absent, Pediculidae – absent

Anoplura Family Differences: Eyes

Haematopinidae – absent, Linognathidae – absent, Pediculidae – present

Anoplura Family Differences: Row of Hairs on Abdominal Segment 1

Haematopinidae – many, details for other families not specified in the source

Anoplura Family Differences: Size

Haematopinidae – large, Linognathidae – small, Pediculidae – medium

Family Haematopinidae

Short-nosed lice

Haematopinus tuberculatus

Affects carabaos and buffaloes in Asia and the Pacific

Haematopinus quadripertusus

Affects cattle and buffaloes in temperate and tropical regions

Haematopinus eurysternus

Affects cattle, absent in the Philippines

Haematopinus bufali

Affects buffaloes in South Africa

Haematopinus suis

Affects swine, largest anopluran found in domestic animals

Haematopinus asini

Affects horses

Haematopinidae Life Cycle

After a blood meal, adult lays eggs or nits attached to hair close to skin at the neck, shoulder, flank, and lower abdomen, eggs hatch into first-stage nymphs after 2–3 weeks, nymph molts 3 times within 15 days at approximately 5 days per molt, adults develop and become sexually mature after 3 days, entire life cycle takes 23–32 days

Family Linognathidae

Long-nosed lice

Linognathus vituli

Cattle, present in the Philippines, long-nosed cattle louse

Linognathus africanus

Goats and sheep, sucking louse of sheep and goats

Linognathus stenopsis

Affects goats

Linognathus pedalis

Sheep, foot louse of sheep

Linognathus ovillus

Sheep, body/blue/face louse of sheep

Linognathus setosus

Dogs, canine sucking louse

Solenopotes capillatus

Cattle, tubercled lice, reported from imported cattle

Microthoracius cameli

Camel and dromedary in Africa and Asia

Microthoracius praelongiceps

Llama in South America

Linognathidae Life Cycle

Eggs are dark blue when laid and attached to hairs of the dewlap, sides of neck and face, or anywhere during heavy infestation, eggs hatch into nymphs after 10–13 days, nymph molts 3 times within 15 days, entire life cycle takes 23–27 days

Family Pediculidae

Includes Pediculus humanus capitis – human head louse, P. humanus corporis – human body louse, P. eurygaster – occurs in macaques, P. obtusus – occurs in monkeys and baboons, Phthirus pubis – crab or pubic louse, occurs in pubic region and may also occur in armpits, eyelashes, eyebrows, beard, and mustache

Pediculidae Life Cycle

Eggs attached to hairs, hatch into nymphs after 5–10 days, nymph molts 3 times within 21 days, entire life cycle takes 3–4 weeks

Other Important Families of Anoplura

Hoplopleuridae, Echinophthiriidae

Polyplax serrata

Occurs in mice, transmits Eperythrozoon and Francisella spp.

Polyplax spinulosa

Occurs in mice and rats, transmits Haemobartonella

Hoplopleura acanthopus

Occurs in mice

Hoplopleura captiosa

Occurs in mice

Hoplopleura pacifica

Occurs in rats

Haemodipsus ventricosus

Occurs in rabbits

General Characteristics of Hoplopleuridae

Paratergal plates project apically from the body, tergal and sternal plates usually distinct

Family Echinophthiriidae

Antarctophthirus microchir occurs on sea lions, Echinophthirius spp. occurs on various pinnipeds including sea lions, fur seals, and walruses, body densely covered with thick setae sometimes modified into scales

Effects of Sucking Lice on the Host

Causes irritation, pruritus, biting, and scratching, thickened pigmented darkened skin called Vagabond's disease, shaggy rough matted hair coat, hairballs in the stomach, restlessness and interrupted feeding causing weight loss and reduced milk/meat yield, considerable anemia, lameness caused by foot lice, reduced body resistance to viral and bacterial diseases, Haematopinus suis may transmit African swine fever virus and swine pox virus, attracts myiasis flies

Human Body Louse as a Vector

Rickettsia prowazekii – epidemic typhus, Rickettsia quintana – trench fever, Borrelia recurrentis – relapsing fever, Yersinia/Pasteurella pestis – plague, Pasteurella tularensis – tularemia, poliomyelitis virus

Suborder Mallophaga

Biting or chewing lice, obligatory ectoparasites mainly of birds and to a lesser extent mammals, about 3,800 species in 253 genera, most species exhibit strict stenoxeny, up to 20 lice species may occur on one bird species, size 0.5–14 mm, wingless and dorsoventrally compressed, body divided into caput, thorax, and abdomen

Two Divisions of Mallophaga

Amblycera – 30% of all avian species, Ischnocera – 70% of all avian species

Damalinia bovis/Trichodectes scalaris

Cattle, absent in the Philippines and present in the United States

Damalinia equi

Biting louse of horses

Damalinia ovis

Biting louse of sheep

Damalinia limbata

Biting louse of goats

Trichodectes canis

Biting louse of dogs, reported in the Philippines but not common

Heterodoxus spiniger

Biting louse of dogs, most common biting louse of dogs in the Philippines

Heterodoxus longitarsus

Occurs on kangaroos and wallabies

Felicola subrostratus

Biting louse of cats, common in the Philippines, especially stray cats

Gyropus ovalis

Occurs on guinea pigs and other rodents, present in the Philippines

Gliricola porcelli

Occurs on guinea pigs and other rodents

Trimenopon hispidum

Occurs on guinea pigs

Mammalian Biting Lice Life Cycle

Eggs or nits attached to hairs close to the host's skin, hatch into nymphs after 5–8 days, nymph molts 3 times within 3–4 weeks, entire life cycle takes 26–30 days

Effects of Mammalian Biting Lice

Severe irritation and restlessness, Trichodectes canis and Heterodoxus spiniger serve as intermediate hosts of Dipylidium caninum, pruritus and skin lesions from scratching, reduced production due to interrupted feeding

Control of Mammalian Lice

Spray or dip livestock with 0.06% Coumaphos, 0.5% Malathion, 0.5% Chlordane, 0.15% Neguvon, 0.5% Sevin, or 0.5% Coumaphos, dust with 5% malathion dust or 5% Sevin powder, apply ointment containing 5% rotenone in 10 parts petrolatum, use ivermectin, shave carabaos and buffaloes during summer

Biting Lice of Poultry

Common external parasites of poultry worldwide, spread by direct contact between birds and litter, adults survive 4–5 days away from birds, size 1–6 mm, life cycle takes 3 weeks, Menacanthus stramineus is the most pathogenic and may cause anemia in heavy infestations, check flocks for rapidly moving insects at feather bases on the abdomen or around the vent, crusty egg clusters or nits may be visible at feather bases

Chicken Lice

Menopon gallinae – shaft louse, Menacanthus stramineus – body louse, M. pallidulus – small body louse, M. cornutus – body louse, Lipeurus caponis – slender wing louse, Oxylipeurus dentalus – neck louse, Goniodes dissimilis – brown louse, Goniodes gigas – large body louse, Goniocotes gallinae – fluff louse, Cuclotogaster heterographus – head louse, absent in the Philippines

Turkey Lice

Menacanthus stramineus, Menopon gallinae, Chelopistes/Goniodes meleagridis, Oxylipeurus polytrapezius

Pigeon Lice

Menopon giganteum, Columbicola columbae – most common, Campanulotes bidentatus, Colpocephalum turbinatum

Duck and Goose Lice

Trinoton anseris, Menopon gallinae, Anaticola crassicornis, Anaticola anseris, Holomenopon leucoxanthum – causes wet feather in ducks

Quail Lice

Menopon gallinae, Goniocotes spp.

Poultry Lice Life Cycle

Eggs attached to feather bases singly or in clusters, a pair of lice may produce 120,000 adults in a few months, entire life cycle takes 2–3 weeks, lifespan is several months on the host and 5–6 days off the host

Effects of Poultry Lice

Unthriftiness and weight loss, anemia, reduced production, Menacanthus stramineus is the most injurious poultry louse and may carry equine encephalitis virus, Menopon gallinae transmits ornithosis

Control of Poultry Lice

Spray or dust large flocks with Malathion, Sevin, Neguvon, or Coumaphos, dip small numbers of birds in insecticides, repeat application after 2 weeks to prevent nymphs from reaching maturity, then repeat twice a year