What bit me


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  • What bit me

    1. 1. What Just Bit Me?A Short Primer on Arthropods of Medical Importance
    2. 2. Rosmarie Kelly, PhD MPHPublic Health EntomologistGDPH – 2 Peachtree St NWAtlanta, GA 30303404-657-2912 (w)404-408-1207 (c)rmkelly@dhr.state.ga.usrpk8@cdc.govhttp://health.state.ga.us/epi/zvbd/http://www.Gamosquito.org 2
    3. 3. First, some background info… 3
    4. 4. What is Entomology? - the branch of zoology that deals with the study of insects What is Medical Entomology?• the study of insects that carry diseases• may also deal with other arthropods that carry disease (ticks & mites)• may deal with insects & other arthropods that are considered pests by humans A Public Health Entomologist works in the realm of public health 4
    5. 5. What is a pest?1. an annoying or troublesome person, animal, orthing; nuisance.2. an insect or other small animal that harms ordestroys garden plants, trees, etc.3. a deadly epidemic disease, especially a plague;pestilence. 5
    6. 6. Arthropods that are considered pests by humans are primarily found in 2 classes:• Arachnida – spiders, ticks, mites• Insecta – the insects 6
    7. 7. We define pests in terms of our own standards of good and bad --standards that are often based largely on aesthetics, economics, andpersonal welfare, and shaped by cultural bias and personal experiences.A "pest" is defined as any organism that causes annoyance or injury tohuman beings, human possessions, or human interests.The injury may be physical (bites and stings), medical (causing illness ordisease), or economic (monetary loss to goods or property). Injury mayarise directly from the pest itself, or may develop indirectly as a result ofthe actions or behavior of the pest. 7
    8. 8. In reality, many of the insects and otherarthropods we label as pests are essential components of our natural ecosystem. The species we regard as pests usually affect us in one or more of the following ways: • They are an annoyance or nuisance • They endanger human health or safety • They threaten the welfare of useful plants or domestic animals • They damage stored products or structural materials 8
    9. 9. Out of the 800,000 - 1,000,000 species of insectsthat have been described so far, not more than1,000 (about 1/10 of 1%) can be regarded asserious pests, and less than 10,000 (about 1%)are even occasional or sporadic pests. 9
    10. 10. Aesthetic pests cause no damage and inflict no injury.They may be annoying, unsightly, or disruptive (like chirping crickets that keep youawake at night, or dance flies that swarm around your head in the spring), but theirpresence will cause no injury or financial liability.An insect is most likely to be regarded as an aesthetic pest when it inadvertentlyinvades a home or business establishment. 10
    11. 11. Agricultural pests• Of all the insect species now living on earth, at least half of them (400,000 - 500,000) feed directly on the tissues of living plants. – Herbivores with chewing mouthparts consume a plant directly. – Plant tissue is also damaged by herbivores with piercing-sucking mouthparts.• Many insects that feed on plants also serve as vectors of plant diseases. 11
    12. 12. Pests of Medical ImportanceIt is impossible to measure the full impact of insects and otherarthropods on human health and welfare.• These organisms have the capacity to inflict injury, disease, discomfort, or distress.• They can be a direct cause of illness, pain, and suffering through bites and stings, infested wounds, or allergic reactions.• They feed on blood or body tissues and they may transmit deadly pathogens or parasites.Economic losses associated with these pests are borne not only by the affectedindividuals and their families, but also by human society in general.• Losses include not only the direct costs of medicine and health care, but also indirect costs resulting from stress, absenteeism, and reduced productivity.• These are costs that are not easy to measure in dollars and cents. 12
    13. 13. Many of the Medically Important Arthropods are Hematophagous (they feed on blood) 13
    14. 14. All of the arthropods thatcan pierce human skin havemouthparts that areespecially adapted forpiercing, cutting, or burrowing.These include:• Diptera (mosquitoes, black flies, horse flies, deer flies, stable flies, sand flies, and various biting midges)• Hemiptera (bed bugs, assassin bugs, water bugs)• Thysanoptera (thrips)• Phthiraptera (sucking lice)• Siphonaptera (fleas)• the class Arachnida (spiders, mites, and ticks) 14
    15. 15. Salivary enzymes and other compounds, such as anti-coagulants, anesthetics, and vasodilators also may be injectedby the mouthparts during feeding.The localized reaction to an insect bite (pain, swelling, redness,etc.) is usually a physiological (inflammatory) response to theseinjected compounds. Although the amount of blood taken by each insect may be quite small, the cumulative effects of blood feeding by large populations of hematophagous insects can be life- threatening. 15
    16. 16. Contrary to popular belief (and the internet), you can not reliably tell what bit you by looking at the bite. Identification of the source of the bite is important in order to determine whether to seek emergency medical attention, call your doctor, or treat the bite at home. The best way to do this is to see what bit you. 16
    17. 17. And now to the topic at hand…What is a primer?An old-fashioned school book thatcontains very basic facts about asubject.1. An elementary textbook forteaching children to read.2. A book that covers the basicelements of a subject. 17
    18. 18. A is for: ARTHROPODAll insects are arthropods but not all arthropods are insects! 18
    19. 19. What is an arthropod?The arthropods constituteover 90% of the animalkingdom and are classified inthe phylum Arthropoda.They are distinguished fromother animals by:• an exoskeleton (a skeleton on the outside of the body)• body divided into distinct parts• jointed legs and appendages• May have wings and antennae• bilateral symmetry (both sides of the body are the same) 19
    20. 20. B is for: BUGSAnother truism: all bugs are insects; not allinsects are bugs.A “bug” is one of the 35000 or so speciesin the order Hemiptera.Many bugs are considered a nuisance,especially in agriculture.Some bugs are pests of medicalimportance because they transmitdiseases. 20
    21. 21. Hemipterans have piercing-sucking mouthparts Hemipterans feed on a variety of liquids, including blood. 21
    22. 22. What is that! nymph eggs female male22 Bed Bugs
    23. 23. LIFE CYCLEFemale bed bugs deposit 3 to 8eggs at a time; a total of 200-500 eggs can be produced byone female over her 10 monthlife span.The eggs hatch in 4-12 days.Bed bugs go through 5 nymphalstages before reachingmaturity. This usually takes 35-48 days. 23
    24. 24. Reactions to BitesThe bite of a bed bug is painless.Common allergic reactions include the development oflarge welts that are accompanied by itching andinflammation.The welts usually subside to red spots but can last forseveral days.Blister-like eruptions have been reported in associationwith multiple bed bug bites and anaphylaxis may occur inpatients with severe allergies. 24
    25. 25. C is for:COLEOPTERA(beetles andweevils), thelargest order inthe class Insecta. 25
    26. 26. What is that!Blister beetles receive their commonname from the ability of theirhemolymph to produce blistering oncontact with human skin.Hemolymph is often exuded copiouslyby reflexive bleeding when an adultbeetle is pressed or rubbed.Blisters commonly occur on the neck andarms, as the result of exposure to adultbeetles attracted to outdoor lights atnight. 26
    27. 27. D is for:• Diptera, the true flies Flies are insects. Diptera means two wings; di = two, ptera = wings. The hind pair of wings are reduced to a couple of knob-like balance organs. 27
    28. 28. What is that? Psorophora ciliata (shaggy- legged gallinipper) This is the largest blood sucking mosquito in the US. The larvae are large and are predacious upon other larvae. The adult inflicts a painful bite.Larval habitat: flooded fields, temporary ground pools, and ditches.Adult habitat: fields and yardsBiting activity: Anytime of the day when disturbed.Flight range: 1-2 miles 28
    29. 29. What is that!Myiasis is the infestation of the organs or tissuesof host animals by the larval stages of dipterousflies, usually known as maggots or grubs.The fly larvae feed directly on the hosts necrotic or living tissue. The hostsare usually mammals, occasionally birds and, less commonly, amphibians orreptiles. TYPES • dermal, sub-dermal or cutaneous (creeping) • nasopharyngeal • ocular • intestinal/enteric or urinogenital • open wounds - traumatic • boil-like, the lesion is termed furuncular • bloodsucking myiasis - sanguinivorous 29
    30. 30. Medical Myiasis• Not all flies associated with myiasis are deleterious or otherwise a nuisance to their vertebrate hosts.• Some species of Calliphoridae (blowflies) have been observed on infected wounds since the mid-1500’s.• History: – Ambroise Paré (1509-1590), the chief surgeon to Charles IX and Henri III, discovered in 1557 during the battle of St. Quentin that maggots often infested pus-forming wounds. – In 1829, Baron Dominic Larrey the chief surgeon to Napoleon found that these infestations prevented infection and hastened healing.• Today, these beneficial maggots serve as an adjunct to modern medicine rather than solely as a last resort.• They are used to treat several maladies including the foot wounds of diabetic patients. 30
    31. 31. Disease TransmissionMosquitoes are estimated totransmit disease to more than 700million people annually in Africa,South America, Central America,Mexico and much of Asia withmillions of resulting deaths.In Europe, Russia, Greenland,Canada, the United States, Australia,New Zealand, Japan and othertemperate and developed countries,mosquito bites are now mostly anirritating nuisance; but still causesome deaths each year. 31
    32. 32. H is for: HYMENOPTERAInsects - ants, bees, wasps, hornets sting and bite 32
    33. 33. Hymenoptera • The best defense against hymenoptera is to avoid them • When ants, bees, wasps, or hornets attack, run! • Pain, redness & swelling are normal at the sting site • Anyone with >15-25 stings should seek medical attention 33
    34. 34. 34
    35. 35. What is that! The European hornet, Vespa crabro, is the largest of the European eusocial wasp. The queen measures 25 to 50 mm (1–2 in) long; males and workers are smaller. European hornets are attracted to lights at night… 35
    36. 36. What is that! The velvet ant, or cow killer, is a wasp. Females are wingless and covered with dense hair. The males have wings. 36
    37. 37. Africanized Honey Bees• “Killer Bees”• Originally brought to South America from southern Africa in 1956 (crossbreeding program)• Areas of colonization: every Latin American country except Chile; Arizona; New Mexico; Nevada; Texas; California; Mississippi; Florida; … and Georgia??? 37
    38. 38. I is for:• Insect – 3 body parts – 6 legs – 1 pair antennae – 0, 1, or 2 pairs of wings Remember, all insects are arthropods but not all arthropods are insects! 38
    39. 39. Growth & Development• Metamorphosis Gradual – adults & nymphs usually eat the same food and live in the same habitat Complex – adults & larvae eat different foods and live in different habitats• Molt to increase size 39
    40. 40. L is for:• Lepidoptera, the moths and butterflies – Lepidoptera are insects. – The name Lepidoptera, derived from the Greek words "lepido" for scale and "ptera" for wings, refers to the flattened hairs (scales) that cover the body and wings of most adults. – Although many Lepidoptera are valued for their beauty, and a few are useful in commerce, the larvae of these insects are probably more destructive to agricultural crops and forest trees than any other group of insects. 40
    41. 41. Urticating (irritating) Caterpillars• Urticating hairs can be of two distinct types – Envenomating hairs • Tubular • Hold venom – Non-envenomating hairs • Fragile • Irritating• Contact - wheals and widespread rashes that can be accompanied by a burning sensation 41
    42. 42. What is it! Moths in the genus Calyptra are sometimes known as vampire moths, a colorful name referring to the ability of at least some species to pierce mammalian flesh and feed on blood. 42
    43. 43. M is for:• Mites – small arthropods that can infest animals, plants, and stored foods and include important disease vectors• Mites are wingless, lack antennae and are flat or round bodied• Adults have eight legs, although the first immature stage has only six legs• All members have piercing-sucking mouthparts 43
    44. 44. Chiggers• Chiggers are the juvenile form (larvae) of a mite in the family Trombiculidae.• Chiggers are barely visible to the naked eye (their length is less than 1/150th of an inch).• They are red in color and are most easily seen when clustered in groups on the skin.• The juvenile form has six legs; the (harmless) nymphal and adult mites have eight legs.• They do not suck blood but cut into the skin, inject skin-digesting saliva and suck up the liquefied skin 44
    45. 45. Scabies• Very small & rarely seen• They burrow into the skin• Reaction: initially, little irritation; after about a month, a rash appears• Common bite areas: skin between the fingers, bend of the elbow & knee, penis, breasts, and shoulder blades 45
    46. 46. P is for:• Phthiraptera, the lice – small, wingless, parasitic insects 46
    47. 47. www.headlice.org Head Lice (Pediculosis)• Infestation of the hair on the scalp by Pediculus humanus capitus, or the human head louse• Live by biting and sucking blood from the scalp• Problem common in schools and institutions• 6-12 million people worldwide are infested each year• Three forms of lice: nit, nymph, and adult 47
    48. 48. What bit me!Phthirus pubis – crab louse 48
    49. 49. S is for:• Siphonaptera, the fleas – Fleas are insects – As adults, all fleas are blood-sucking external parasites – In addition to their irritating bites, fleas may also transmit pathogens that cause disease in humans and other animals – Cat and dog fleas are intermediate hosts for a tapeworm (Dipylidium caninum) that infects dogs, cats, and humans• Ever heard of the plague? 49
    50. 50. The Black Death (1347 – 1350)The Black Death came in three forms. All forms were caused by a bacteriumcalled Yersinia pestis. In some cities, as many as 800 people died every day.• bubonic plague was the most commonly seen form of the Black Death (mortality rate was 30- 75%)• pneumonic plague was the second most commonly seen form of the Black Death (mortality rate was 90-95%)• septicemic plague was the most rare form of all (mortality was close to 100%) The economy was probably hit the hardest of all the aspects of Europe. The biggest problem was that valuable artisan skills disappeared when large numbers of the working class died. This eventually lead to a change in the society structure. 50
    51. 51. T is for:• Ticks – Ticks are arthropods, like spiders. – Two families of ticks, Ixodidae (hard ticks) and Argasidae (soft ticks), are important to humans because of the diseases or illnesses they can transmit or cause.• Ticks are the leading vectors of diseases to humans in the United States, second only to mosquitoes worldwide. 51
    52. 52. Don’t Do This to Remove a Tick• Put vaseline on it• Put fingernail polish over it• Put mineral oil on it• Drench it with whiskey, wine, or other alcoholic beverages• Stick a lit match on it (or a recently extinguished match)• Especially do not combine the above flammable materials with the match treatment! 52
    53. 53. Resources• http://www.cals.ncsu.edu/course/ent425/text18/pestintro.html• http://www.emedicinehealth.com/ticks/article_em.htm• http://emedicine.medscape.com/article/769067-overview• http://www.crcpress.com/product/isbn/9780849385391• http://www.agius.com/hew/resource/arthrop.htm• http://www.who.or.id/eng/contents/aceh/wsh/books/evc/evc-02.pdf• http://lancaster.unl.edu/pest/resources/medspider006.shtml• http://www.medicinenet.com/chiggers_bites/article.htm• http://www.cdc.gov• http://health.state.ga.us/epi/zvbd/And many, many more. Be careful though. There is a lot of mis-informationout there. Take a Disease and History class if you ever get a chance. 53
    54. 54. "There was an old lady whoswallowed a spider thatwiggled and jiggled andtickled inside her. Sheswallowed the spider tocatch the fly. I dont knowwhy she swallowed the fly.Perhaps shell die." Insects and Arthropods in Poetry and Folklore 54
    55. 55. ANY QUESTIONS? 55