Economic importance:
Myiasis:
Blowflies have caught the interest of researchers in a variety of fields, although the large body of literature on calliphorids has been concentrated on solving the problem of myiasis in livestock.
It is estimated that the sheep blowfly Lucilia cuprina causes the Australian sheep industry over $170 million a year in losses.
The most common causes of myiasis in humans and animals are the three dipteran families Oestridea, Calliphoridae, and Sarcophagidae.
Myiasis in humans is clinically categorized in six ways: dermal and subdermal, facial cavity, wound or traumatic, gastrointestinal, vaginal, and generalized myiasis.
If found in humans, the diptera larvae are usually in their first instar. The only treatment necessary is just to remove the maggots, and the patient heals naturally.Whilst not strictly a myiasis species the congo floor maggot feeds on mammal blood, occasionally human.
Screwworms:
The New World Primary Screwworm (Cochliomyia hominivorax) once a major pest in southern United States, has been eradicated from the United States, Mexico and Central America through an extensive release program by the USDA of sterilized males. See Sterile insect technique.
The USDA maintains a sterile screwworm fly production plant and release program in the eastern half of the Republic of Panama to keep fertile screwworms from migrating north. Currently this species is limited to lowland tropical countries in South America and some Caribbean islands.
The Old World primary screwworm (Chrysomya bezziana) is an obligate parasite of mammals. This fly is distributed throughout the Old World, including: Southeast Asia; tropical and subtropical Africa; some countries in the Middle East; India; the Malay Peninsula; the Indonesian and Philippine Islands; and Papua New Guinea.
The fly is an agent of myiasis, which is the infestation of tissue on a living mammal. The secondary screwworm (Cochliomyia macellaria) has become one of the principal species on which to base postmortem interval estimations because its succession and occurrence on decomposing remains has been well defined.
The secondary screwworm is found throughout the United States, the American tropics, and in southern Canada during summer months. This species is one of the most common species found on decomposing remains in the southern United States.
Maggot therapy:
MDT or Maggot Debridement Therapy is the medical use of selected, tested and disinfected fly larvae, including blow-fly maggots, for cleaning non-healing wounds. Lucilia sericata (Phaenicia sericata), or the common green bottle fly, is the preferred species used in maggot therapy.
Medicinal maggots do three things: clean out wounds by eating away the dead, infected tissue, kill off the bacteria, and stimulate wound healing. One problem with this type of therapy is that some species of flies eat healthy tissue as well, including screwworms. This type of therapy can be used to treat pressure ulcers, diabetic foot wounds, venous stasis ulcers and post surgical wounds.
Disease:
Adults may vector pathogens of diseases such as dysentery. Flies, most commonly Calliphoridae, have frequently been associated with disease transmission in humans and animals as well as myiasis. Studies and research have linked Calliphora and Lucilia to vectors of causal agents of bacterial infections.
These larvae, commonly seen on decaying bodies, feed on carrion while the adults can be necrophagous or vegetative. During the process of decay, microorganisms (e.g. mycobacterium) may be released through the body. Flies arrive at the scene and lay their eggs. The larvae begin eating and breaking down the corpse simultaneously ingesting these organisms which is the first step of one transmission route.
Paratuberculosis in cattle, pigs and birds (M. a. avium) have been isolated and recovered from these flies through several different experiments. Other potential vectors and threatening diseases include Rabbit Hemorrhagic Disease Virus in New Zealand and flystrike.
Although strike is not limited to blow flies; these maggots are a major source of this skin invasion causing lesions, and if severe enough, may be lethal. Strike starts when blow-flies lay eggs in a wound or fecal material present on the sheep. When the maggots hatch, they begin feeding on the sheep and thus irritating it.
As soon as the first wave of maggots hatch, they attract more blow-flies causing the Strike. Currently, there is no insecticides for blowfly prevention, but precautionary measures may be taken, such as docking tails, shearing, and keeping the sheep healthy overall.
Salmonellosis has also been proven to be transmitted by the blow fly through saliva, feces and tarsi. Adult flies may be able to spread pathogens via their sponging mouthparts, vomit, intestinal tract, sticky pads of their feet or even their body or leg hairs.
As vectors of many diseases, the importance of identifying the transmissible agents, the route of transmission, and prevention, treatments in the event of contact are becoming increasingly important. With the ability to lay hundreds of eggs in a lifetime and the presence of thousands of larvae at a time in such close proximity, the potential for transmission is high especially at ideal temperatures.
Forensic importance:
Blow-flies are usually the first insects to come in contact with carrion because they have the ability to smell dead animal matter from up to ten miles (16 km) away. Upon reaching the carrion, females deposit eggs onto the body. Since development is highly predictable if the ambient temperature is known, blow-flies are considered a valuable tool in forensic science.
Traditional estimations of time since death are generally unreliable after 72 hours and often entomologists are the only officials capable of generating an accurate approximate time interval. The specialized discipline related to this practice is known as forensic entomology.
Calliphora vicina and Cynomya mortuorum are important flies of forensic entomology. Other forensically important Calliphoridae are Phormia regina, Calliphora vomitoria, Calliphora livida,
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