Medically Important Arthropods - Micro Flashcards
Head lice, scabies mites and public lice are from what category
Ectoparasites - Do not transmit germs but live and feed permanently on exterior of the host
Mosquitoes, fleas, body lice, tsetsefly are examples of what?
Vectors - They actively transmit disease causing pathogens. By bite or feces of vector
Cockroaches, flies are categorized as what?
Mechanical transporters - Transmit disease passively by picking up pathogen in stool and then contaminating human food
What are “harmful” anthropods?
They cause nuisance, discomfort and blood loss through their bites. Mosquitoes, bugs, Fleas etc
Properties of anthropods ?
- Body is segmented bearing jointed appendages (jointed feet)
- Invertebrates, exoskeleton made of chitin
- Bilaterally symmetrical
- Tubular alimentary canal with mouth and Anus
Classification of anthropods?
Arachnida
Insecta
Crucataceans
Genus of Arachnida?
Acari - Tick, mice
Scorpiones - scorpion
Araneae - Spider
Genus of insecta ?
Anoplura - Lice
Siphonaptera - fleas
Hemiptera - bugs
Diptera - mosquitos and flies
Examples of crucataceans ?
Podocopida- Shrimps
Decapoda - crabs, crayfish
Cyclopoida - cyclops
What features differentiate insects from arachnids
Presence of antennae, wings, segmented abdomen in insecta
3 pairs of legs - Insecta and 4 pairs of legs - Arachnida
Three distinct body (head, thorax abdomen) - Insecta
Two distinct body (cephalothorax and abdomen) - Arachnids
Crustaceans features?
They have 2 pairs of antennae (Insects have 1)
Three pairs of chewing appendages
Varied number of legs
Legs on their abdomen and also on thorax (different from insecta)
Arachnids features ?
Four pairs of legs are attached to the cephalothorax
Adapted to kill prey using poisonous glands, fangs or stingers
A pair of pedipalp which aid in chewing and chelicerae is attached to the cephalothorax
They undergo incomplete metamorphosis
Medical importance of scorpions?
Compounds found in scorpion venom can be used to produce new drugs
Black mamba venom has power painkiller potential
Pathogenicity of scorpion bite ? Pain swelling inflammation at bite site
- Pain, swelling, inflammation at bite site
- Severe cases; muscular spasm, respiratory failure, pulmonary edema and shock
Most dangerous spider species?
Black widow spider
- Venom is neurotoxic affecting the CNS.
- Can cause cramps in legs, arm and chest
- symptoms; Headache, fever, nausea, tremor and stuttering
Medical importance of Ticks ?
Tick paralysis; progressive flaccid paralysis due to failure of release of ACH at NMJ
Tick Toxins - produce a block in motor nerve fibers
Hard bodied ticks carry what ?
Carriers of Rickettsia, spirochetal, viral, bacteria and protozoan disease
Soft Bodied ticks ?
Vectors for endemic relapsing fever and Q fever
Diseases associated with mites are ?
- Scabies
- Scrub typhus
- Rickettsial Pox
Body is oval shaped, convex dorsally and flattened ventrally
The developmental change in the lifecycle of insect is called ?
Metamorphosis
Complete metamorphosis consists of what? And incomplete consists of what ?
Complete - Egg, Larva, pupa and adult
Incomplete - Egg, Nymph and adult (three stages)
Note- Nymph is similar but smaller to adult form and size is proportional to its age
Types of vectors in insects ?
1)Biochemical vectors; Acquire pathogen via feeding, agent multiplies, propagate and develops inside the arthropods body.
2) Mechanical Vector; they transmit pathogens by way of secretions and contaminated external body surfaces. Pathogens do not multiply in them
*^Wingless** insects with short legs are called?
Lice
- Dorsoventrally flattened body with segmented abdomen
- Average life span of 30days
- Has three pairs of clawed legs
The head louse is called?
Pediculus humanus capitis
- Elongated body and narrow anterior mouthparts
- Feeds on human blood from the scalp
- Female louse produce sticky substance that firmly attaches each egg to the base of hair shaft less than 1/4inch (5mm) from scalp
