Sucking Lice and Bed Bugs Quiz

Sucking Lice

• Wingless insects, ectoparasites on mammals
• Mouthparts adapted for sucking tissue fluids and blood
• Two antennae with five segments
• No sexual dimorphism
• Thorax small, three segments fused
• Abdomen relatively large, seven segments visible
• Paratergal plates: dark brown or black thickened chitin at the sides of the abdomen
• Eyes reduced or absent
• First pair of legs usually smaller with weaker claws
• Third pair of legs usually the largest
• Each tarsus has only one claw
• Tibial pad: A spiny pad that helps to hold the louse in the hair

Common Examples of Sucking Lice

• Haematopinus asini: Sucking louse of equines
• H. bufali: Sucking louse of buffalo in Africa
• H. suis: Large louse of pigs
• H. eurysternus: 'Short-nosed' cattle louse

Bed Bugs

• Cimex lectularius
• Attacks humans and animals to suck blood
• 4-5 mm long, flat-bodied, elongate oval shape
• Yellowish brown to dark brown in color
• Head bears long antennae with four joints
• Eyes project at the side of the head
• Wings are vestigial
• Abdomen has eight visible segments
• Whole body is covered with spinose bristles and some hairs
• Tibiae are long and tarsi have three joints
• Adults have a pair of ventral thoracic stink glands
• Mouthparts are modified for piercing and sucking
• Labrum is small and immovable

Bed Bug Life Cycle

• Females lay about 150-200 eggs in dark crevices
• Larvae hatch after 3-14 days at 23 degrees C or longer
• There are five nymphal stages
• Adult stage is reached in 8-13 weeks after hatching
• Bugs can live long and survive starvation
• They are nocturnal insects but will bite in the daytime
• After a blood meal, bugs defecate and turn around near the wound

Bed Bug Control

• Chlordane
• Dieldrin
• DDT
• Organophosphates
• Oil-based sprays with pyrethrins

Fleas

• Wingless insects with laterally compressed bodies, 1.5-4 mm long
• Chitinous covering is thick and brown
• Compound eyes are absent, some species have large or small simple eyes
• Abdomen has ten segments
• Ninth abdominal segment bears a dorsal plate called sensilium or pygidium
• Penis (aedeagus) is chitinous and coiled
• Legs are long, strong and adapted for leaping
• Combs or ctenidia: Large spines on the head and thorax

Common Flea Species

• Ctenocephalides felis: Cat, dog, man, mouse, rat and primates (cosmopolitan)
• Ctenocephalides canis: Restricted to dogs and related species (cosmopolitan)
• Archaeopsylla erinacei: Hedgehogs in Europe and North America. Found also in dogs and cats
• Spilopsyllus cuniculi: Restricted to rabbit and hare
• Leptopsylla segnis: Occurs on the house mouse, rat, field mouse, wild rodents
• Ceratophyllus fascialtus: Common rat flea
• Xenopsylla cheopis: Oriental or black rat flea
• Pulex irritans: Human flea may occur on pig, dog, cat, and rat
• Tunga penetrans: Man, pig, and baboon
• Ceratophyllus gallinae: Common flea of chicken
• Ceratophyllus columbae: Domestic pigeon
• Echidnophaga gallinacea: Common chicken flea in tropical and subtropical areas

Flea Life Cycle

• Female flea lays up to 20 eggs at a time and some 400-500 during her lifetime
• Oval eggs are deposited in dust or dirt, laid on the host, soon drop off
• 0.5 mm long, rounded at the poles and pearly white in color
• Larvae may hatch in 2-16 days
• Larvae are elongate, slender, maggot-like, consisting of 3-10 abdominal segments with long hairs
• Last segment bears hooked processes called anal struts for holding and locomotion

Flea Larval Stage

• Larvae are creamy yellow in color, very active, and hide from light
• With masticatory mouthparts, they feed on dry blood, feces, and other organic matter
• They are found in crevices in floors, carpets, nest litter, sleeping places
• Larval development takes 7-10 days or longer
• Pupal stage lasts 10-17 days under average condition, may last several months

Flea Health Effects

• Mostly found in animals with poor condition, debilitating disease, and old animals.
• Animals are restless, lose weight, and spoil coats by biting and scratching.
• At the site of infection, elevated levels of immunoglobulin E and eosinophilia.
• Severe pruritic reactions at the lumbar-sacral area, abdomen, inside hind legs, and neck.
• Hyperpigmentation and hyperkeratinization.
• 'Miliary dermatitis', flea hypersensitivity in cats associated with small papules and pruritus.
• Important in transmitting diseases.
• Bubonic plague (Yersinia pestis) carried by Xenopsylla cheopis.
• Tularemia (Francisella tularensis) transmitted by rat flea.

Flea Control

• Flea collar with dichlorvos
• Coumaphos (Asuntol)
• Corticosteroids to reduce pruritus
• Premises should be clean with insecticides.
• Chlorinated Hydrocarbons
• Diazinon or malathion