Title: Medical arachnoentomology. Arthropods as pathogenic organisms and carriers of agents of infections and invasions Lecturer: ass. Nedoshytko Khrystyna
1Medical arachnoentomology. Arthropods as
pathogenic organisms and carriers of agents of
infections and invasions
Lecturer ass. Nedoshytko Khrystyna
2Plan 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. 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.
5Class Crustacea
- 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).
6Class 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.
7Class Arachnida includes 3 orders of medical
importance
Order Scorpiones.
Order Araneae (spiders)
Order Acari (ticks and mites).
8Class ArachnidaOrder Scorpiones Scorpions
E. Tenczar
E. Tenczar
Flat Rock Scorpion,Hadogenes troglodytes,female,
native toSouth Africa
Lined Devil Scorpion,Vaejovis spinigerus,female
from Arizona with young
9Interesting 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.
10Scorpions 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 SymptomsA 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
- .
11Stepwise 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.
12Spiders 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
13Arachnophobia
- 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
14Spider 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
15How 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.
16Order 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.
17SarcoptidaeScabies 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.
18Sarcoptes 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.
-
19small male large female
20Distribution
- Worldwide
- All races and socioeconomic classes
- All climates
- 300 million cases annually!
21Behavior
- 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.
22Scabies Rash
23Life cycle
24Transmission
- 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.
25Diagnosis
- 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).
27TICK 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).
29Anatomy of IXODES ticks
30Size
31Female Deer Tick
32Female 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 CrimeanCongo hemorrhagic fever and
Lyme disease.
33Ticks
- Medical importance.
- - Mechanical injury by the bite.
- - Tick paralysis progressive flaccidity due to a
failure of acetylcholine liberation in the
neuromuscular junction. Ticks toxin produces a
block in the motor nerve fibers. The toxin is
elaborated by the ticks 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
34Insects
- 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.
35Insects
- 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).
-
36Order 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. It cant 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.
38Lice
- 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.
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40Transmission 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). They are a nuisance but NOT a health
hazard. - Lice dont 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
42Order 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
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44Flea eggs
45Adult fleas
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47Important Flea Species
Xenopsylla cheopis (Oriental rat flea) - primary
urban plague vector Pulex irritans (human flea)
- occasional epidemic plague vector Ctenocephalid
es felis, C. canis, - cat and dog flea - primary
pest species Tunga penetrans sand flea (chigoe)
48Parasitic Flies Order
Diptera
49Flies - Diptera
- The key distinguishing adult structure two
wings. - All Flies are Holometabolous (having a complex
metamorphosis - i.e. egg, larvae pupa, and adult)
50One 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
51Diptera 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)
52Diptera Flies as parasites
- Adults ectoparasites (or blood feeding) but
larvae develop within female and essentially
pupate after emerging from mother (Glossina,
Hippoboscidae)
53Diptera 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
54Myiasis 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 hosts ingested food.
55Metallic Flies
56Lucilia spp.
Calliphora spp.
57Musca domestica.
- Housefly is a medium-sized fly, 6- 10 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.
58House 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.
60Mosquitoes
- Bloodfeeding - only females take blood
- Males feed on plant sugars
- Gonotrophic cycle - feed, egg development,
oviposition (half-gravid, gravid)
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
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62Differences between Anopheles and Culex.
Eggs 3 strategies
- Singly on water surface
- Anopheles
- Singly in a pile, on moist substrates
- Aedes/Ochlerotatus
- Form of a raft, on water surface
- Culex
- Culiseta
63Larval Stage Growth Stage
- Larval instars (4)
- Aquatic, Filter feeders
- Respiration
Anopheles
64Pupa Lighter than water
Pupal Stage Comparison
Anopheline
Culicine
65Mosquito Pupa and Larvae
66Mosquito Emerging from Pupal Exuvia
67 Adults
Emergence Mating Feeding
Adult Stage Comparison
Culicine
Anopheline
68Culex
Anopheles
Aedes aegypti
69Thank you for attention !