screw worms

Discussion in 'Predators and Pests' started by chickengeorgeto, Nov 26, 2016.

  1. chickengeorgeto

    chickengeorgeto Overrun With Chickens

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    The New World Screw Worm has reemerged in South Florida. Keep a close watch on your birds because Screw Worms are dangerous as a switch blade knife. Hopefully the USDA will be able to banish them again but this pest is not something that you want to help survive for the sake of diversity.

    From the pages of the New York Times, America's News Paper of Record:

    "BIG PINE KEY, Fla. — The first signs seemed baffling: deer stumbling around in confusion, howling in pain, found with their heads hideously disfigured — as if eaten alive.
    What biologists discovered turned out to be even more frightening: the reappearance of a parasite known as the New World screwworm fly that had not been seen in the United States since the 1970s and had been considered eradicated.
    State and federal officials are hopeful that the infestation, which so far is restricted to Florida’s southernmost Monroe County, is being controlled. Symptoms were first reported in wild deer in July, and laboratory tests in late September confirmed the presence of the screwworm, which is the larva of the screwworm fly.
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    The infestation has the potential to cause catastrophic damage to livestock and is being seen by some experts as a reminder of the challenges of controlling the spread of diseases and infestations in a world of limitless global travel and trade.
    “In the very big picture, this is just the latest example of our failure to adequately protect people, agriculture and the environment from consequences of a shrinking world, an interconnected word,” said Adam Putnam, Florida’s commissioner of agriculture. “Millions of cargo containers and millions of passengers arrive every year, entering and exiting Florida and bringing unwelcome pests and disease with them.”
    In July, Florida Key deer, the smallest subspecies of the white-tailed deer, started turning up with grotesque wounds. The tiny deer are the last of their kind — only about 875 remain — and live in the wild at a federal refuge in the Florida Keys that was established to protect them in 1957.
    Eight deer died in July and August, and 11 more died during the September mating season. Refuge managers at first thought the injuries were abscesses caused by males puncturing one another with their antlers during the rut, when they fight for dominance. Employees at the refuge, many of whom were not even born the last time the screwworm was found in the United States, had never seen anything like it.
    In all, about 15 percent of the existing endangered Key deer herd — 132 animals — have died since July. Infections were also found in two stray cats, a dog and a pet pig. Officials worry that if the screwworm spreads to ranches and farms, it could cause up to $1 billion in livestock losses.
    “We had no idea what this thing was,” said Kristie Killam, a ranger at the National Key Deer Refuge, the 9,200-acre center run by the United States Fish and Wildlife Service. “There was a few here and there in July and August, but it was September, when the rut started, that we started scratching our heads and saying, ‘This is a little bit out of the ordinary,’” she said, adding, “It looks like a horribly infected wound, an infected wound that never got treated, infected with mushy maggots.”
    Lab test results in late September confirmed the presence of the screwworm. Native to South America, it first appeared in the United States in the 1800s. Screwworms are larvae laid by flies in the open wounds of an animal, where the larvae feed on flesh. The fly is a little bigger than a common housefly, with orange eyes and a metallic dark blue or gray body with three dark stripes down its back.
    An animal quarantine was imposed by officials in Florida in early October, and an agricultural emergency was declared to avoid the spread of the parasite.
    An infestation in the southeastern United States from the 1930s to the 1950s caused $20 million a year in livestock losses and took 20 years to eradicate, according to the United States Department of Agriculture.
    Since that infestation, the federal government has spent millions of dollars in the last century to keep the screwworm out of Mexico and Central America, lauding it as “one of the greatest success stories in the history of agriculture in the Americas” — only to see it reappear in South Florida.
    Some critics said the authorities should have reacted faster to the threat. They said the delay could cause the infestation to spread, imperiling the one million head of cattle in Florida.
    “If private veterinarians or government agencies were aware there was something going on in the pet and deer population and didn’t report it, that’s the example of the breakdown I’ve just been venting about,” Mr. Putnam, the state agriculture commissioner, said.
    Officials involved with the eradication program disagreed.
    “This had not been around since the ’50s and ’60s,” said Dan Clark, the manager of the refuge. “My staff wouldn’t have worked professionally with anything like that. Even a lot of veterinarians just had never seen it,” he said, adding, “Any reasonable person would have done what we did.’’
    To eradicate the screwworm, seven million fly pupae sterilized by radiation are being released each week in the Florida Keys. The female mates only once in her lifetime, so the idea is that if the female mates with a sterilized fly, the screwworm infestation should be eradicated in about six months.
    For the first time since the outbreak began, no deer died in the last week, showing that those measures and antiparasitic medications fed to the deer are beginning to show signs of success, the Fish and Wildlife Service said in a statement on Thursday.
    The authorities have also set up a mandatory inspection station along the two-lane highway leading to the Florida Keys, where anyone transporting an animal out of the county must stop to have it checked. Nearly 5,000 animals — from chickens to cats, horses and even an ape — were inspected without any parasite findings.
    Brian McCluskey, the associate deputy administrator for veterinary services for the federal Agriculture Department, said it was unclear how the screwworm returned to the United States, but it could have come from someone traveling by boat from Cuba, where the screwworm is present. It is also present in Haiti and other countries, so lab tests will have to be used to determine the origin. The refuge is in a part of Florida that has been a common landing spot for smugglers dropping off Cuban migrants, who sometimes bring their pets.
    Dr. John H. Wyss, a retired veterinarian who ran the Agriculture Department’s eradication program in Central America for 12 years, said it took 50 years to eliminate the screwworm from the southern United States to Panama. A serious infestation could take two to three years to eliminate, he said.
    “The real economic threat would be to the livestock in Florida,” Dr. Wyss said. “It would be a tremendous cost.”


    If you do find Screw Worms on your poultry contact me for ways to eliminate them.
     
    Last edited: Nov 26, 2016
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  2. Folly's place

    Folly's place Chicken Obsessed

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    x2!!! Screwworms are a nightmare parasite, gone for my adult life here, but now back. It's 'One World', all right, and we all need to watch out for them, on all our critters down south. UGH!!! Mary
     
  3. casportpony

    casportpony Team Tube Feeding Captain & Poop Inspector General Premium Member

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    How does one treat an animal with them?

    -Kathy
     
  4. Folly's place

    Folly's place Chicken Obsessed

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    It's fly strike on steroids. Nasty insecticide dips for large animals; basically, a trench with a tank filled with water/ insecticide, that livestock got to jump into and swim through, including immersing the head, with residual action, before coming into the USA from Mexico. Saw pictures long ago in school. I'm not sure what Florida is doing now, need to look it up. For an individual animal, it's insecticide, wound cleaning, and management, as with fly strike up here. Horrible! Mary
     
  5. Folly's place

    Folly's place Chicken Obsessed

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    There's a lot coming up if you google it right now. I didn't look; saw all I needed to see years ago. Mary
     
  6. casportpony

    casportpony Team Tube Feeding Captain & Poop Inspector General Premium Member

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    Nasty little bugs!

    http://parasitipedia.net/index.php?option=com_content&view=article&id=2555&Itemid=2833

    SCREWWORM FLIES of LIVESTOCK, HORSES, DOGS and CATS : biology, prevention and control. Cochliomyia, Chrysomya
    Screwworms are cutaneous myiases (i.e. infections with fly maggots) especially harmful for livestock. The affect mainly gazing cattle and sheep, but can attack whatever wild and domestic mammals, including horses and occasionally humans and birds as well. Dogs and cats can be affected, mainly in rural areas.
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    They are found worldwide in tropical and subtropical regions, with a species-specific distribution.
    The most relevant species are:
    • Chrysomya bezziana, the Old World screwworm; occurs mainly in tropical Africa and Asia.
    • Chrysomya megacephala. Occurs mainly in Africa and Asia, in the same regions as Chrysomya bezziana, but also in America where it was introduced early in the 20th century.
    • Cochliomyia hominivorax, The New World screwworm. After the large-scale eradication campaigns in North America (down to to Panama) it remains very common in South America.
    • Cochliomyia macellaria. Occurs in America.
    Chrysomya bezziana and Cochliomyia hominivorax are obligate parasites, i.e. they cannot complete their life cycle on alternative substrates such as carrion, dung or manure, but only on their living hosts. They are also called "primary" myiases, because they are the first flies colonizing the injuries. Although they cannot pierce or otherwise damage the skin of their hosts, they deposit their eggs on minuscule injuries such as those caused by other parasites (e.g. ticks, biting flies) or on any kind of wounds that livestock can get, both occasional (through fencing, vegetation, etc.) or operational ones (e.g. after castration, dehorning, parturition, tail docking, shearing, etc.).
    Chrysomya megacephala and Cochliomyia macellaria are "secondary" myiases, i.e. they deposit their eggs on injuries already infested with larvae of primary screwworms. They extend and worsen the wounds already infested with maggots.
    Other species of both genus Cochliomyia and Chrysomya are facultative parasites, i.e. they can survive on carrion and/or other organic substrates. Some species are of forensic interest because they colonize cadavers and enable a quite accurate determination of the time of death.


    Biology and life cycle of screwworm flies

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    Adults of Cochliomyia hominivorax, the New World screwworm, are medium-sized flies, about 10 mm long. Their body shows metallic greenish-bluish colors, and the eyes are red-orange. The life cycle can be completed in about 3 weeks. Adult femalesdeposit 200 to 400 eggs on injuries of the host, even on minute ones such as insect bites. And they also are capable of laying eggs on uninjured, soft body parts (perineum, body openings, corners of the yes, etc.). Egg laying happens mostly in the afternoon and evening, which prevents exposure of hatching larvae to direct sunlight. Each female lays a total of about 3'000 eggs in her lifetime. Larvae hatch out of the eggs within hours and start feeding on the host's tissues, progressively deepening and extending the injury. If larvae are disturbed while feeding they burrow deeper in the tissues like a screw: this is why they are called "screw"-worms. Besides digestive enzymes larvae release toxins that prevent wound healing. Open injuries become infected with secondary bacteria. Blood and pus attract other flies that worsen the wound. Larvae mature in about 1 week and reach up to 2.5 cm length. Mature maggots drop to the ground, burrow themselves in the soil and pupate within hours. Adult flies hatch already 3 to 5 days later, depending on temperature. By unsuitable weather hatching can be delayed for several weeks. Mating occurs in the vegetation. Females mate only once and keep the sperms in a reservoir for fertilization of the eggs that are progressively produced and deposited. This specific behavior strongly supported the sterile-male release technique used to eradicate these flies in most of North America. By suitable conditions 8 to 10 generations can follow within one season. Adult flies are excellent fliers, capable of traveling up to 250 km in two weeks. Cochliomyia hominivorax prefers habitats with abundant trees and humid environments. It avoids open landscapes and arid regions.



    Harm and economic loss due to screwworm flies


    If wounds infested with maggots are left untreated, fly larvae fed into the animals flesh and affected animals can die in less than 2 weeks: they are actually eaten alive. If they survive, they are severely weakened and more susceptible for other diseases and parasites. The hides are strongly damaged and are downgraded at slaughter.
    Cochliomyia hominivorax was considered the most damaging pest of cattle and sheep in the USA before its eradication (completed in the 1960's). Already in the 1930's damage to the livestock industry in the US was estimated at above $200 million. Thanks to the eradication program it has been eliminated from Mexico, several Caribbean Islands, Guatemala, Honduras, Costa Rica, Nicaragua and down to Panama. Nowadays it remains one of the most damaging pests in South America and parts of Central America.
    Chrysomya bezziana was and remains a highly damaging pest for cattle, sheep and goats in endemic regions in tropical Asia and Africa. Regional incidence depends strongly on climatic and ecologic conditions. In favorable years regional outbreaks can become a tremendous pests for livestock.
    Non chemical control and prevention of screwworm flies

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    The eradication of Cochliomyia hominivorax in the USA, Mexico and most of Central America is the biggest success story of biological control in veterinary medicine. It has been achieved using the sterile male techniquedeveloped by R.C. Bushland and E.F. Knipling, two North American entomologists in the 1950's. This technique has been also applied successfully to several crop pests in the USA and elsewhere. It consists in releasing billions of industrially produced male flies previously sterilized through X-radiation. These sterile males compete successfully with natural fertile males and mate with the females, which subsequently produce no offspring. After several years releasing sterile males, natural fly populations are decimated and eventually collapse and disappear from the concerned region. Such a campaign includes an enormous logistic effort for producing and releasing the sterile males at the right places and in the right moment and quantity, and for monitoring the fly populations in vast regions where the campaign is being run. The current eradication campaign aims at eliminating Cochliomyia hominivorax down to the Isthmus of Panama and to establish a permanent biological sterile-male barrier there to prevent its re-introduction from South America.
    The same sterile-male release approach was used to successfully control an outbreak of Cochliomyia hominivoraxaccidentally introduced into Libya in the 1990's, which threatened to spread to the whole Old World with potential catastrophic consequences for the livestock industry.
    There have been no serious attempts to eradicate Chrysomya bezziana, in the Old World using this technique.
    Strictly speaking the sterile male technique is not a "biological" control method, since biological control is usually restricted to the use of natural enemies of a pest, and sterilized males are obviously not natural enemies of the females of the same species. However, it is an excellent alternative to whatever chemical control methods since it leaves no pesticide residues in food commodities and the environment.
    Learn more about biological control of flies and other insects.
    Where screwworms are a pest, i.e. in South America, and tropical regions of Africa and Asia, best prevention is to avoid handling practices that cause injuries to livestock during the peaks in the fly season. This includes parturition, castration, dehorning, shearing, tail docking, etc. that attract egg laying flies to the resulting injuries.
    Preventing infestations with blood sucking parasites (e.g. ticks, horn flies, stable flies, horse and deer flies, etc.) will also reduce the incidence of screwworms, because screwworm flies are also attracted to such minute wounds as those caused by these parasites.
    Traps have also been used to reduce fly populations, often in combination with the sterile-male technique previously mentioned.
    For the time being there are no vaccines that will protect animals by making them immune to screwworms. There are no repellents, natural or synthetic that will keep screwworm flies away from animals.
    Click here if you are interested in medicinal plants for controlling lice and other external parasites of livestock and pets.
    Chemical control and prevention of screwworm flies

    Many concentrates used for periodically dipping or spraying livestock or horses against ticks and flies will usually kill established screwworm infestations as well, but only those that contain synthetic pyrethroids (e.g. cypermethrin, deltamethrin, permethrin, etc.) and organophosphates (e.g. chlorpyrifos, chlorfenvinphos, coumaphos, etc.), not those with amitraz. However, protection against re-infestation will last only for a few days. Pour-ons (backliners) with such parasiticides are often not suitable because they do not ensure complete coverage of the host's body.
    Otherwise numerous ready-to-use dressings for direct treatment of injuries infested with maggots are available in most countries. They are used preventively for topical treatment of injured body parts after castration, dehorning, shearing, etc., as well as curatively for killing maggots already established in whatever injuries that animals can get. Such dressings are available in various formulations such as powders, lotions, ointments, creams, sprays, aerosols, etc. They contain larvicides belonging to the synthetic pyrethroids (e.g. cypermethrin, deltamethrin, permethrin), carbamates (e.g. carbaryl, propoxur) and organophosphates (e.g. chlorpyrifos, diazinon, trichlorfon, etc.). These dressings often contain disinfectants, painkillers, and/or wound healing chemicals as well. Such dressings for livestock or horses are sometimes approved for use on dogs and cats as well.
    Systemic macrocyclic lactones (e.g. doramectin, ivermectin, moxidectin) have an excellent efficacy against screwworms. Classic injectables (i.e. containing 1% active ingredient) will cure established myiases and protect livestock for several weeks against re-infestations. They are vastly used as preventatives in livestock after management operations that bear a risk of screwworm infestation (e.g. castration, dehorning, etc.). Pour-onformulations are usually also effective against screwworms. Drench or other oral formulations are usually not effective enough.
    Insecticide-impregnated ear-tags (for cattle) or collars (for dogs and cats) are not adequate for protecting against screwworm flies.
    So far there are no effective repellents to keep screwworm flies away from livestock, horses or pets.
     
    Last edited: Nov 26, 2016
  7. FlyWheel

    FlyWheel Chillin' With My Peeps Premium Member

    I see no mention of poultry (any kind), although I harbor no illusion that they are immune. What concerns me would be the treatment of an infected bird. Is there a preventative? Something that could be added to their dust bath perhaps? Spraying wouldn't be that effective on an animal covered with feathers.
     
  8. Folly's place

    Folly's place Chicken Obsessed

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    Kathy's previous post has good information, and there's lots more information out there if you google it. Being alert to any injury, wound, or illness, is important, and then it's instant action before things get out of hand. Hopefully this outbreak can be put to rest before it travels north! Mary
     
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