subject: Biological features and Clinical features of Fleas and Bugs [print this page] Fleas Fleas
Fleas are wingless insects. They are bilaterally compressed and covered with stiff hairs directed backwardly. Strong legs help fleas to jump. They are of the Order siphonaptera which all display complete metamorphosis.Morphology
An Adult flea is 2-3mm in size. Body is divided into head, thorax and abdomen. Head is round or angular and carries 2 simple eyes (may be absent). Ocular hairs are located in front or below the eyes. Post cephalic hairs may be present. Two short 3-segmented antennae lie in the grooves behind the eyes. proboscis is used for piercing and sucking. Thorax consists of 3 segments and carries 3 pairs of strong legs. 10 segmented abdomen carries a sensory plate (pygidium or sensilium) on the dorsal side of the 9th segment. The male has a spring- like aedeagus. The dorsal surface of abdomen is flat or concave. The female has a comma-shaped spermatheca. The dorsal surface of abdomen is convex. Eggs are pearly white, oval, 0.5mm in size and have blunt ends. Worm-like larva consists of head, thorax (3 segments) and abdomen (10 segments). All segments carry hairs directed backward. The last abdominal segment has a pair of conical processes (anal struts). Pupa is enclosed in a cocoon.Life cycle
Eggs are laid on the ground (chaps, floor cracks, burrows of rodents). Eggs hatch after a few days. Larvae come out and pass through 3 instairs. The mature larva (about 2 weeks) spins a cocoon of viscid substance. The adult is developed in about one week and comes out. The whole cycle takes from 1 to 3 months. Fleas are either temporary ecto-parasites (human flea) or permanent ectoparasites (rat flea). They feed on blood more than once daily, but can withstand starvation for a long time.Medical importance
Vector of plague which is caused by Yesina Pestis. The bacilli multiply and block the gut. Infection occurs by the bite of the blocked flea. Vector of murine typhus caused by Rickettsia typhi. Rickettsia invade the gut wall of the flea and multiply. After rupture of epithelial cells they are liberated into flea's lumen and come out with the feces. Mode of transmission of murine typhus is contamination of bite wound or mucous membranes by feces. Flea may be a vector of tularemia. Occasionally flea serves as intermediate host for Hymenolepis nana. Bites of fleas cause itching and scratching with possible development of secondary (bacterial) infection.Control of fleas
Human flea is controlled by cleanliness and sweeping of dust from floor and carpets; application of insecticides and repellents (naphthaline). Dog and cat fleas can be controlled by dusting the resting places of animals with insecticides. Rat flies are controlled by applying rodent control measures (use of rodenticides and dusting of rodent burrows with insecticides).Order Hemiptera (bugs)
Body is flattened dorso-ventrally. Wings are present or may be in rudimentarily state. Bugs display incomplete matamorphosis. Order Hemiptera includes 2 families of medical importance (cimicidae and Reduvidae).Family Cimicidae, CImex lectularius (bedbug)
Adult bug is about 5mm in size, male is smaller than female. Body is dark brown and divided into head, thorax, and abdomen. Bugs are temporary ectoparasites. They feed by night and hide during the daytime. They can withstand starvation for a long time. Bedbugs emit a characteristic odor. naturally bedbugs are not known to transmit any disease. Very rare mechanical transmission can occur. Experimentally, it can transmit relapsing fever (Borrelia recurrentis) and Chagas' disease (Trypanosoma cruzi). The bites of bedbug are irritating and may lead to insomnia. It is controlled by cleanliness. repair of cracks, manual collection of bugs and their destruction and also by application of insecticides to hiding places.Family Reducidae (Triatoma, reduvid bug, cone-nose or kissing bug)
Triatoma bug is the vector of Chagas' disease (American trypanosomiasis). Chagas' disease occurs primarily in rural central and south america. The reduvid bug lives in the walls of rural huts and feed at night. It bites preferentially around the mouth or eyes, hence the name is "kissing bug". Infection occurs by contamination of bite wound with feces. Prevention of chagas' disease involves protection from reduvid bite, improved housing and insect control.I am Funom Theophilus Makama. I advertise through writing. As a platinum expert Author, I write lots of articles and hence promote interested websites, companies, groups, organizations, and communities through publishing and distributing my articles. For more information on this interesting venture, click on the link belowhttp://funom-makama.blogspot.com/2010/07/advertising-contracts.html
Biological features and Clinical features of Fleas and Bugs
