Arthropods PDF

1. Mange-producing mites: 1. Genus: Sarcoptes Species : Sarcoptes scabei (only 1)- affect most species (aswell as humans!!) Disease: sarcoptic mange Infective stage : nymphs or fertilised females (through direct contact or fomites) Morphology: Rounded bod...

1. Mange-producing mites: 1. Genus: Sarcoptes Species : Sarcoptes scabei (only 1)- affect most species (aswell as humans!!) Disease: sarcoptic mange Infective stage : nymphs or fertilised females (through direct contact or fomites) Morphology: Rounded body with setae and spines Round capitulum (head) Suckers at the end of limbs (females - 1st and 2nd pairs, males- 1st,2nd,4th pairs) = sexual dimorphism Pedicels on the rest of legs (females - 3rd+4th, males- 3rd) Life cycle: Egg —> larvae —> nymph stages: protonymph - deuteronymph - tritonymph —> adults (which lay the eggs) (general life cycle) = Males will fertilise the deuteronymphs so that the female adults are laying eggs already Location: epidermis (Burrowing mite!): 1. Females burrow deeply into the layers of the skin to lay eggs and faeces (in the epidermis) 2. Larvae develops here, becomes all 3 nymph stages then becomes adult 3. Males search for deuteronymphs and fertilises them (so they are ready to lay next eggs as adults) Disease: (sarcoptic mange) - affects most animals Scabing Dry skin Hyperkeratosis - thickening of stratum corneum (outermost epidermal layer) Alopecia Intense itching 2. Genus: Psoroptes Species: Psoroptes ovis Disease: Psoroptic mange Infective stage: Morphology: Longer legs (than Sarcoptes) Pointed capitulum (head) Suckers with 3 jointed appendixes Males - shorter Location: Areas with wool and fur Ears (uses its chelicera and mouthparts to damage skin and feed on lymph) Disease: (generally in all animals) = Psoroptic mange Affects ungulates (sometimes rabbits- most severe in rabbits) Promotes alopecia Epidermis is not affected therefore no scabs when hair falls Rabbits - ears affected,cracks on skin and skin thickening (can look like Sarcoptes) 3. Genus: Octodectes Species: N/A Disease: Otodectic mange Infectious stage: Morphology: (similar to Psoroptes) Difference is that suckers have no jointed appedix and has a less rounded capitulum Feeds on lymph Location: EARS!! Species: mainly cats 4. Genus: Knemidocoptes Species: N/A Disease: N/A Morphology : Similar to Sarcoptes but has smaller feet (minion looking) Location: beak,feathers and legs of birds 5. Genus: Demodex Species: D. folliculorum, D.canis, D.bovis… Disease: Demodicosis - e.g Canine demodicosis Morphology: Elongated body with 2 differentiated regions : podosoma (leg insertions- CR), opisthoma (after that - CD which is striated) Location: Found inside hair follicles Sebaceous glands (feeds onto fatty acids) Disease: Canine demodicosis = Produces foliculitis (inflammation and swelling of the follicles) Pathology: Most humans harbour it (not too harmful) Produces foliculitis Can transmit : Streptococcus pyogenes bacteria which is an acne producer Mostly effects immunocomprimised animals as it can invade vital organs 6. Genus: Cheyletiella Species: Cheyletiella blackei (cats) Known as the ‘walking dandruff mites’ Morphology: palpal claws 7. Genus: Neotrombicula Species: Neotrombicula autumnalis Parasitic stage: only larval stages = only 3 pairs of legs are parasitic (nymphs and adults are not!) Common at end of summer and autumn 4. Non-mange producing mites: 1. Genus: Dermanyssus Species: Dermanyssus gallinae Disease: Dermanyssus infestation/ red mite infestation Morphology: Gnathosoma has chelicerae Elongated maxipalps Spiracles (after the last coxa) Females longer than males Species: Birds Sometimes humans = zoonotic Characteristics: Nocturnal feeding habits - during the day they hide Hematophagous!! (leads to anemia, weight loss and irritation on animals) 2. Genus: Varroa Species: Varroa destructor Disease: Varroosis Species: Honey bees - can affects the larvae and adults Vector of DWV - Deformed wing virus