Structure Cuticle Epicuticle; Wax, cement layer -> waterproofing, color Exocuticle: sclerotized -> protection, support Endocuticle: Soft, pliable -> flexibility were needed (joints) Epidermis: Secretes the cuticle 1Segmentation Tagmosis: Fusion of segments to create new functional units 2The insect mouthparts 3Generalized*layout*of*respiratory*system:*spiracle*body*wall*muscle*fibers*tracheoles*main*trachea*(longitudinal*trunk)*4Pa>ern*of*circula?on*wing%heart%dorsal%&%ventral%septa%nerve%cord%heart%ganglion%leg%extension%of%ventral%septum%leg%dorsal%vessel%(aorta)%leg%ampulla%antenna%haemocoel Heart%with%one:way%valve%of%os<um%The%haemolymph%transports:%Nutrients%Hormones%Immune%cells%/proteins%Waste%products%%5Vision %Ocelli:%Damselfly%Jumping%spider%ocellus Compound%eyes:%Omma<dium:%6Insect wings Direct Flight Muscles Indirect Flight Muscles Hinge 7Global*Public*Health*Entomology**Lecture*3:%Allergens,*Venoms*and*Poisons*8What*is*an*allergic*reac?on?*A*rela?vely*harmless*substance*(allergen)*elicits*an*outJofJpropor?on*reac?on*of *the*immune*system*9Types*of*allergic*reac?ons*1)*Local*allergic*reac?ons:*******Where*the*allergen*makes*contact*with*body*:******lung,*nose,*skin*(e.g.*house*dust*allergy,*mosquito***********bite)***2)*Large*local*reac?ons:******OQen*peak*12*hours*aQer*exposure******Can*be*strong*enough*to*constrict*blood*vessels*or********nerves*to*extremi?es*****These*may*last*as*long*as*10*days**10%3)*Systemic*allergic*reac?ons*(anaphylax is):*******More*likely*to*occur*when*allergen*reaches*blood*or*lymph*and********spreads*through*body**à ******Most*extreme*case:*anaphylac?c*shock*%%%Type*of*allergic*reac?ons*cont’d**These*are*most*oQen*caused*by*wasp,*bee*and*ant*s?ngs*If*you*have*a*systemic*reac?on*you*are*at*risk*for*developing*anaphylac?c*shock*next*?me*you*are*stung*Dangerously*low*blood*pressure*and*constric?on*of*bronchia*11Signs*and*symptoms*of*anaphylaxis*General:*** *****Apprehension,*uneasiness,*weakness**Cutaneous: *****Redness,*Itching,*Rash,*Swelling**Gastrointes?nal:*****Abdominal*cramps,*vomi?ng,*Diarrhea**GenitoJurinary: *****Urinary*or*fecal*incon?nence**Respiratory: *****Chest*?ghtness,*Wheezing,*trouble* * **************breathing***Cardiovascular:********Dizziness,*lightheadedness,**************************************low*blood*pressure***12• *A*systemic*r eac? on*usually*begins*with*a******widespread*rash*or*swelling**• *In*the*extreme*case*a**severe*allergic*reac?on******can*cause*death*by*anaphylac?c*shock*within*10J***15*minutes**(20J30*minutes*is*more*common)*Signs*and*symptoms*of*anaphylaxis**Cont’d*Dangerous drop in blood pressure 13Management*of*allergic*reac?ons:**Local*reac?on:% %%%%%%%%%%%%%An?histamines*and*topical*cor?costeroids**%Severe*local*reac?on:%%%%An?Jhistamines;*Systemic*steroids;* * ****************HighJpotency*topical*steroids;***************Rest*and*eleva?on*of*limb;***************Avoid*exercise****************** * *If*swelling*occurs*near* Eye,*Throat,*Ear*****or*swelling*is*wide*spread* ****à*seek*medical*a>en?on*Systemic*reac?on: **Ice*pack*may*delay*absorp?on*of*venom;******Epinephrine*kit*(if*available)*** * *Emergency*room;*IV,*tracheal*tube,* ****an?histamines,*cor?costeroids,*oxygen ***14Common*Arthropod*causes*of*allergic*reac?ons:*Blood*feeding*insect*bites:*Mosquito*bites*Flea*bite*15Common*Arthropod*causes*of*allergic*reac?ons*Cont’d*Bites*and*S?ngs:**Bees,*Ants,*Wasps,*Black*Widow,**(Brown*Recluse)**Most*likely*to*cause*Systemic*reac?ons*16Inhala?on*of*body*parts:**House*mites;*cockroaches;*mass*emergences*of*caddisflies*and*mayflies%*Symptoms:***• *Infl amma?on*of*nose*mucous**** * *******membranes*• *Eczema*(rash,*itching)*• *Hives*(welts)*• *Asthma*17Inges?on*of*insect*parts:**Cockroaches;*adult*beetles*(weevils,*mealworms);*Moths;*fly*larvae**e.g.*Mealworm*can**infest*food*sources*Symptoms:**Diarrhea;*abdominal*pain;*periJanal*itch*Management:**Food*hygiene,*avoiding*foods**1819Arthropods with venomous bite Spiders Centipedes Bites are (mostly) for subduing and pre-digestion of prey 20Centipedes: ** • *Mostly*nocturnal:***Hide*during*day,*******emerge*at*night*to*hunt**• *3,000*species**• *Largest*ones*(Scolopendra):***Very*painful*bite*(usually*****subsides*within*6J8*hours)***Rarely*fatal**Anxiety,*vomi?ng,*irregular*pulse,*dizziness*and*headache**Example of mostly harmless centipede: The house centipede -very useful, eats lots of small bugs in your house Larger specimens can inflict a small bite 21Texas Scolopendromorph Centipedes: 11 Species Giant Redheaded Centipede (up to 9” long) Largest and most significant one: distribution 22Spider*Bites**• *36,000*species,*all*but*one*family*are***venomous**• *Only*a*few*dozen*produce*medically*****significant*bites*in*humans.****• *In*US:*three*groups*of****problema?c*spiders:**1 .*Brown*Recluse**2 .*Widow*spiders*3 .*Hobo*spiders*(?)*23Recluse*spider*(Violin*spiders)*Brown*recluse*or**fiddleback*spider**Distribu?on**• *Brown*recluse*is*most*problema?c**• *13*species*in*the*US*that*can*produce****necro?c*lesions****J>*three*produce*most*bites:**Loxosceles(reclusa***Brown*recluse*(L.(laeta(((Chilean*recluse*(L.(arizonica((Arizona*Brown*spider(*• *Venom*is*necro?c**(not*neurologic)**• *Brown*Recluse*prefers*warm*and*dry*areas****(woodpiles,*cellars**of*houses)**• *OQen*when*you*find*one,*there*will*be*others**• *Ac?ve*during*the*nighcme**24How to recognize one? 3 pairs of 2 eyes, separated by space between them. (Other spiders have eight eyes) Yellow sac spider Brown recluse 25How*oQen*do*they*bite?**• *Symptoms*can*vary*from:***1.*no*reac?on*2.*mild,*red*wound*3.*necro?c*lesion**• *Very*docile,*bites*almost*always*occur:**1.*during*sleep*2.*inside*clothing*(e.g.*that*is*leQ*on*the*floor*overnight)***• *Systemic*reac?ons*are*exceedingly*rare*This depends on the amount of venom injected 26Necro?c*Lesions*from*Brown*Recluse**• *Can*produce*ulcers*of*1*to*25cm*****(0.5’’*J*10’’)**• *Healing*can*take*months**• *Necrosis:*the*disorganized****breakdown*of*flesh*in*some*part****of*the*body*27Scar*from*necro?c*lesion*Necro?c*Lesions*from*Brown*Recluse*Cont’d**• *Bite*is*usually*painless*un?l*3J8*hours*later**• *Assymetrical*lesions*are*typical*of****Brown*Recluse*Many*necro?c*wounds*caused*by*Stapylococcus*and*Streptococcus(species*are*reported*as*brown*recluse*bites*Venom contains same