1. Medical arachnoentomology
Medical arachnoentomology. Arthropods as pathogenic organisms and carriers of agents of infections and invasions Lecturer: ass. Nedoshytko Khrystyna

2. Plan of lecture
Phylum Arthropoda: general characteristic, classification, medical importance.
Crustaceans as intermediate hosts of helminthes.
Class Arachnida: general characteristic, classification, medical importance.
General characteristics, classification of class Insecta.
Order Anoplura (lice). Morphology, medical importance, methods of control.
Order Siphonaptera (fleas). Morphology, medical importance, methods of control.
General characteristics, classification, medical importance of order Diptera.
Anopheles, Aedes, and Culex mosquitoes and their role in transmission of infections.

3. Three-fourth of all animal species belong to the Phylum Arthropoda
Three-fourth of all animal species belong to the Phylum Arthropoda. The name “arthropod” comes from two Greek words, arthros, jointed, and podes, feet.
All members of the Phylum Arthropoda share the following characteristics:
1. Arthropods have jointed appendages.
2. The arthropod body is segmented.
3. Arthropods have an exoskeleton.
4. Arthropods have a ventral nervous system, an open circulatory system, a digestive system, and specialized sensory receptors.

4. Phylum Arthropoda includes 3 classes of medical importance:
1.Class Crustacea: cyclops, crabs.
2. Class Arachnida (Octapoda): scorpions, spiders, ticks and mites.
3.Class Insecta (Hexapoda): mosquitoes, flies, bugs, lice, fleas.

5. Class Crustacea 2) crabs or crayfish are Intermediate hosts of the
Most crustaceans have two pairs of antennae, three pairs of chewing appendages, various numbers of pairs of legs.
Crustaceans differ from the insects in that they have legs on their abdomen as well as on their thorax.
Medical importance: 1)Cyclopes are intermediate hosts of the fish tapeworm (Diphyllobothrium latum) and Dracunculus medinensis.
2) crabs or crayfish are Intermediate hosts of the
Human lung fluke
(Paragonimus westermani).

6. Arachnids undergo incomplete metamorphosis.
Class Arachnida.
The Class Arachnida is a group of more than 100,000 species, including spiders, scorpions, ticks, and mites.
Most arachnids are adapted to kill prey with poison glands, stingers, or fangs.
Arachnids have a body that is divided into a cephalothorax and an abdomen.
Attached to the cephalothorax are 4 pairs of legs, a pair of chelicerae, and a pair of appendages called pedipalps.
The pedipalps aid in chewing; in some species pedipalps are specialized to perform other functions.
Arachnids undergo incomplete metamorphosis.

7. Class Arachnida includes 3 orders of medical importance:
Order Scorpiones.
Order Araneae (spiders)
Order Acari (ticks and mites).

8. Class Arachnida: Order Scorpiones: Scorpions
E. Tenczar
E. Tenczar
Flat Rock Scorpion, Hadogenes troglodytes, female, native to South Africa
Lined Devil Scorpion, Vaejovis spinigerus, female from Arizona with young

9. Interesting Facts about Scorpions
Scorpions live everywhere except the Arctic and Antarctic
Male and female scorpions find each other by vibration, scent, or touch. Then they dance together for half an hour or more.
Females often eat the males when they are done with the dance.
25 types can harm/kill man
Alive before the dinosaurs
Scorpions have 8 legs and 2 claws.
The bigger the claws are, the less
venom it has.

10. Scorpions differ from spiders in two ways:
Scorpions have greatly enlarged pedipalps, which they hold in a forward position.
They also have a large stinger on the last segment of the abdomen.
Scorpion Sting Symptoms A scorpion sting is never fun. The following are common symptoms of a scorpion sting:
Intense pain at the sting site
Mild swelling around sting site
Numbness in area of sting
Sensitivity to touch
Nausea or vomiting
Excessive salivation .

11. Stepwise first aid
If a scorpion stings you, follow this scorpion sting first aid plan for minimization of pain:
Wash the affected area: If possible, get the site of the sting under cold water immediately.
Medicate topically: Apply a layer of ointment containing an antihistamine, a corticosteroid, and an analgesic.
Apply ice: Hold a bag of ice over the ointment on the area. The ice will reduce the pain and inflammation.
Medicate orally: Take one dose of Benadryl (antihistamine) and one dose of a pain killer (acetaminophen).
Go to the hospital: Because some scorpion stings can be fatal, you will need to go to the emergency room to get evaluated for scorpion anti-venom. If possible, get someone else to drive you.
Ice as needed: Keep applying ice until pain is tolerable.  You may experience pain for any length of time between a few hours to a couple days.

12. Spiders are not a “bug”
Spiders are not insects they are part of a group called Arachnid
There are more than 35,000 different species of spiders

13. Arachnophobia Arachnophobia is the fear of spiders
This is the number one fear of Americans today
Although most spiders are harmless and helpful to our lives
This spider has a venomous bite
that causes serious wounds

14. Spider Eyes Most spiders have either six or eight eyes
Even so they cannot see far away
They use the hair on their bodies as sensors to feel their way around and to tell when other animals are near

15. How dangerous are black widow spider bites?
If a black widow spider bites a person, do not panic!
Very often the black widow will not inject any venom into the bite and no serious symptoms develop. Wash the wound well with soap and water to help prevent infection.
If muscle cramps develop, take the patient to the nearest hospital.
Some victims, especially young children,
may be admitted overnight for observation and treatment.
There is treatment for a black widow spider bite that can take care of the symptoms. Various medications are used to treat the muscle cramps, spasms and pain of a bite. Black widow spider antivenin is seldom necessary.

16. Order Acari Most mites are small, less than 1 mm long,
the adult length from 100 nm to 2 cm.
the cephalothorax and abdomen are fused into an unsegmented ovoid body.
Respiration occurs either by means of tracheae or directly through the exoskeleton.
They are found in virtually every terrestrial, freshwater, and shallow marine habitat known and feed on fungi, plants, and animals; they act as predators and as internal and external parasites of both invertebrates and vertebrates.

17. Sarcoptidae “Scabies Mites”
Sarcoptes scabiei
Also called the “itch mite” of humans
Not Vectors of any disease.
Morphology: male (0,2 mm) is smaller than female (0,4 mm).
Body is oval, convex dorsally and flat ventrally.

18. Sarcoptes scabiei (itch mite)
Mouthparts:
rudimentary hypostome without teeth.
chelicerae end in pincer-like structures.
pedipalps are short and 3-segmented.
The whole cycle takes about 2 weeks.

19. small male large female

20. Distribution Worldwide All races and socioeconomic classes
All climates
300 million cases annually!

21. Behavior Burrowing initially occurs in thinner skin of the body.
Bend of knee and elbow.
Webbing between fingers and folds of the wrist.
Genitalia and buttocks.
Breasts.

22. Scabies Rash

23. Life cycle

24. Transmission Spread by ovigerous female mites through:
Personal (prolonged close) contact
Occasionally by infested sheets (rare).
Touching or shaking hands (unlikely).
Sexual activity.
Among children (outbreaks).
Mites can survive up to 24 hours off host.

25. Diagnosis Diagnosis is made by itching of affected surfaces at night
specific lesions
finding of the parasite in the tunnels by a needle.
Control is provided by
- proper treatment of infected persons
- sterilization of clothes and bedding
- personal cleanliness.

26. Ticks Ticks are divided into hard-bodied ticks (family Ixodidae)
and soft-bodied ticks (family Argasidae)
Ticks are blood-feeding ectoparasites
(parasites that occur on the surface of their host).

27. TICK LIFE CYCLE

28. Life cycle: female ticks lay eggs.
Larvae hatch, feed on blood and then drop to the ground.
Larvae molt into nymphs.
Nymphs feed on blood and molt into adults.
Adult male and female feed on blood.
Life cycle takes several months (1-2 years in some species).

29. Anatomy of IXODES ticks

30. Size

31. Female Deer Tick
Male Deer Tick Crawling

32. Female Deer Tick Larvae
All stages of I. ricinus will feed on humans, and their bite can be painful. This tick can also transmit several diseases that affect humans, including Crimean–Congo hemorrhagic fever and Lyme disease.
Female Deer Tick Larvae

33. Ticks Medical importance. - Mechanical injury by the bite.
- Tick paralysis: progressive flaccidity due to a failure of acetylcholine liberation in the neuromuscular junction. Tick’s toxin produces a block in the motor nerve fibers. The toxin is elaborated by the tick’s ovaries and is secreted by salivary glands.
Vectors of diseases:
-hard-bodied ticks (Ixodidae) are carriers of rickettsial, spirochaetal, viral, bacterial, and protozoan diseases.
soft-bodied ticks (Ornithodorus) are vectors of endemic relapsing fever (caused by Borrelia duttoni) and Q-fever.
Control of ticks:
Repair of cracks.
Insecticide spraying on floors and cracks.
Infested animals are dusted by insecticide agents or dipped in special solution.
In endemic areas: wear light-colored, tightly woven slacks and a long sleeved shirt; spray clothing with an insect repellant containing N,N-diethyltoluamide

34. Insects have three body sections:
the head, thorax, and abdomen;
three pairs of legs, all attached to the thorax;
one pair of antennae.
they may have one or two pairs of wings.
The mouthparts of insects are elaborate.
There are two principal kinds of metamorphosis in insects: simple and complete.

35. Insects Class Insecta is divided into 4 orders of medical importance:
1. Order Anoplura (lice).
2. Order Siphonaptera (fleas).
3. Order Hemiptera (bugs).
4. Order Diptera (mosquitoes and flies).

36. Order Anoplura (lice)
Order Anoplura (lice). Body is flattened dorso-ventrally.
Lice are wingless insects with short legs.
Order Anoplura displays incomplete metamorphosis.
Head louse
Morphology (Pediculus humanus):
Adult louse is 2-5 mm in size, male is smaller than female.
Body is divided into head, thorax and abdomen.

37. The head louse found on humans is specific to people
The head louse found on humans is specific to people. It can’t be contracted from the family dog, cat or any other animal. Mammals and birds can have lice but they are species specific.
These are insects that CANNOT jump or fly.
Their method of movement relies on 6 legs, each of which ends in a claw which can grasp human hair.

38. Lice Life cycle. - Female louse lays about 10 eggs daily.
Eggs are cemented to hairs or to fibers of clothes.
Eggs hatch in about one week.
Nymphs feed on blood and pass through 4 instars.
Adult louse emerges in about two weeks.

40. Transmission of Head Lice
Host-to-host (direct contact from someone who is infested)
By wearing infested clothing (hats, scarves, coats, hair ribbons etc.)
By using infested combs, or brushes
By lying on a bed, couch or carpet that has recently been in contact with an infested person.

41. Head Lice are NOT known to transmit pathogens (germs)
Head Lice are NOT known to transmit pathogens (germs). They are a nuisance but NOT a health hazard.
Lice don’t mount expeditions, striking off to find new heads. They are obligate human parasites, their goal is to stay on the head where they presently live!!!!!
Disease transmission (body louse). Epidemic typhus caused by Rickettsia provaceki, Trench fever. Epidemic relapsing fever

42. Order Siphonaptera (fleas)
About 2500 species, most parasites of mammals
only approx. 100 species on birds
Temporary obligate parasites, blood-feeding exclusively
as adults
Most fleas of medical and veterinary importance are not
host species-specific
increases the potential for acquisition and transmission of pathogens

43. Flea Life Cycle

44. Flea eggs

45. Adult fleas

47. Important Flea Species
Xenopsylla cheopis (Oriental rat flea) - primary urban plague vector
Pulex irritans (human flea) - occasional epidemic plague vector
Ctenocephalides felis, C. canis, - cat and dog flea - primary pest species
Tunga penetrans – sand flea (chigoe)

48. Parasitic Flies Order Diptera

49. Flies - Diptera
The key distinguishing adult structure : two wings.
All Flies are Holometabolous (having a complex metamorphosis
i.e. egg, larvae pupa, and adult)

50. One of Great Adaptations of of Flies - The Habitat of larval stage
The habitat of the larval stage is basically “aquatic or semi-aquatic,” and they have adapted to live in very, very “challenging” environments.
Allows them to invade
Dead and Living tissues

51. Diptera – Flies as parasites
Ectoparasites
Adults are free living but blood feeding with the larvae stages aquatic or in moist semi-aquatic habitats. (Nematocera and Brachycera)

52. Diptera – Flies as parasites
Adults ectoparasites (or blood feeding) but larvae develop within female and essentially pupate after emerging from mother (Glossina, Hippoboscidae)

53. Diptera – Flies as parasites
Endoparasites
Adults free living but larvae are internal or partially internal (flesh feeding) parasites of vertebrates (Oestrus, Gasterophilus, Cochliomyia hominovorax)
Gasterophilus intestinalis

54. Myiasis Defined
The invasion of organs and tissues of humans or other vertebrate animals with dipterous larvae, which for at least a period feed upon the living or dead tissue or, in the case of intestinal myiasis, on the host’s ingested food.

55. Metallic Flies
Cochliomyia hominivorax

56. Lucilia spp.
Calliphora spp.

57. Musca domestica.
Housefly is a medium-sized fly, mm in length; the female is generally slightly larger than the male.
Distribution: cosmopolitan.
Morphology. Adult fly has a gray color. Body is divided into head, thorax, and abdomen.
Life cycle. 1. Eggs are laid into masses of decaying organic substances, garbage, refuse or manure.
2. Larvae hatch in 6-24 hours and feed on organic matter.
3. They molt 2 times giving 3 larval stages.
4. The third larva pupates inside the larval skin.
5. The adult emerges after a few days .The whole cycle takes about one week.

58. House fly 4th vein angled 4 dark stripes Red eyes Breeding media
Garbage
Decaying fruit or vegetables
Decaying meat
Human or animal feces
Grass clippings

59. Medical importance
1. Indirect mechanical transmission of microorganisms (as typhoid, poliomyelitis and bacillary dysentery), eggs of helminthes and cysts of protozoa.
2. Accidental myasis.
Control
Sanitary disposal of refuses, garbage and manure (breeding media) by dumping, burning or application of insecticides.
Control of adult flies by screening or space spraying of insecticides.

60. Mosquitoes Disease transmission
Bloodfeeding - only females take blood
Males feed on plant sugars
Gonotrophic cycle - feed, egg development, oviposition (half-gravid, gravid)
Mosquitoes
Disease transmission
Some species of Anopheles transmit: 1. Human malaria    
2.  Wuchereri bancrofti
Some species of Culex
transmit
1. Wuchereria bancrofti
2. Encephalitis     
3. Rift valley fever

62. Eggs – 3 strategies Differences between Anopheles and Culex.
Singly on water surface
Anopheles
Singly in a pile, on moist substrates
Aedes/Ochlerotatus
Form of a raft, on water surface
Culex
Culiseta

63. Larval Stage – Growth Stage
Larval instars (4)
Aquatic, Filter feeders
Respiration
Anopheles

64. Pupal Stage Comparison
Pupa – Lighter than water
Non-feeding
Respiration
Pupal Stage Comparison
Anopheline
Culicine

65. Mosquito Pupa and Larvae

66. Mosquito Emerging from Pupal Exuvia

67. Adult Stage Comparison
Emergence
Mating
Feeding
Adult Stage Comparison
Culicine
Anopheline

68. Culex
Anopheles
Aedes aegypti

69. Thank you for
attention !