Medical Parasitology Arthropods

1. MEDICAL PARASITOLOGY
ARTHROPODS

2. HUMAN LOUSE PEDICULUS HUMANUS
CAPITIS AND P. H. VESTIMENTI

3. HEMIMETABOLOUS INSECTS

5. MEDICAL IMPORTANCE
 Human lice serve as vector of:
 Rickettsia provazeki- epidemic typhus
 Rochalimaea quintana (Rickettsia quintana)-
trench fever
 Borrelia recurrentis – louse-borne relapsing
fever
 What is the way of transmission?

6. P. HUMANUS CAPITIS

7. Pediculosis-
severe dermatitis

8. Pediculosis

9. MORBUS VAGABUNDORUM
When body lice infestation is
long lasting, heavily bitten
areas of the skin can become
thickened and darkened,
particularly in the mid-
section of the body. This
condition is called
“vagabond’s disease.”

10. MORBUS VAGABUNDORUM

12. PTHIRUS PUBIS- CRAB LICE

13. PTHIRIASIS
Painless blue spots
can appear after
crab lice feed.
Other evidence of
crab lice includes:
rust-colored insect
excretions in
underwear
flakes similar to
dandruff in pubic
hair.

14. PEDICULOSIS PALPEBRARUM
 Mainly in children in poor socio-economic
conditions
 Adults on eyelids and in eyebrows
 Nits on eye lashes and in eyebrows

15. BEDBUG CIMEX LECTULARIUS
May carry agents of :
tularemia
plague
Q- fever
hepatitis B virus
Find human by odour
and warmth

16. Cimex lectularius is very common in urban
areas and can affect public health by
causing:
 direct tissue damage,
 allergic reactions to their secretions,
excrements or body parts
 and by producing systemic toxicity

18. During feeding (predawn hours) the insect
injects saliva containing:
 anticoagulant (inhibitor of factor X
activation),
 vasodilatant (nitric oxide),
 proteolytic enzymes (apyrase)
 and anesthetic compounds

20.  The injected substances cause : skin irritation
and inflammation later on.
 Effect of a bite vary between individuals and the
clinical manifestation is strictly determined by
immunologic status of the host
 Lesions are usually arranged in linear clusters of
three or four known as “breakfast, lunch, dinner”
pattern
 Bites are concentrated on skin that is exposed
while sleeping such as face, neck and
extremities and usually resolve over the course
of 2 weeks.

25.  Increased sensitivity to bedbug faeces
antigens has been demonstrated in
asthmatic patients
 Hypersensitivity reactions – in
sensitive to other insects and exposed
to attacks in prolonged period of time
 Chronic infestation is extremely
stressful leading to nervousness,
pallor, diarrhea, and even iron
deficiency in infants and small children

26. REDUVIIDAE- KISSING BUGS
Triatoma spp.

28. RHODNIUS SP.

31. CHAGAS DISEASE ROMAN’S SYMPTOM

32. FLEAS PULICIDAE
Fleas: plague Yersinia pestis = black
death

33. HOLOMETABOLOUS INSECTS

35. Bubonic Plague
Reservoir phase
• Disease organism: Yrsinia pestis,
a bacterium.
• Reservoir organisms: rodents, especially rats and
ground squirrels
• Up to 120 flea species may transmit the bacterium
• Fleas get sick, digestive tract blocked, unable to feed
normally
• Starving fleas may leave host, attempt to feed from
other animals
• Tend to regurgitate when feeding, injecting bacterium
into blood

36. Human Phase
• Bacterium transmitted by accidental flea bite.
• Contracted initially through flea saliva.
• May be communicated aerially from patients with
advanced, pneumonic form.
• Survivable if treated in first few days, otherwise
may be fatal.
• Endemic in many parts of the world, incl. N. America.
• Ecology: increasing human habitation in wild area
brings people and domestic animals into frequent
contact with rodents.

38. FLEAS PULICIDAE
Fleas: plague Yersinia pestis = black
death

39. TRANSMISSION
 Flea-borne, from infected
rodents to humans
 Direct contact with infected
tissues or fluids from
handling sick or dead
animals
 Respiratory droplets from
cats and humans with
pneumonic plague

41. FLEA - TUNGA PENETRANS
Gravid females penetrates skin
and makes bleeding wounds.

42. TUNGA PENETRANS- SAND FLEA
♀ Permanent
resident of cutaneous
and subcutaneous
tissue:
- between the toes
- near the nail bed
- perianal area
- genital area

43. JIGGERS- T. PENETRANS

47. MALARIA MOSQUITOS ANOPHELES SPP.
vectors of Plasmodium spp.

48. Eggs
When the eggs hatch,
larvae emerge
After the last larval molt
the mosquito becomes a
pupa

49. Ecology
Distribution
Abundance
Population Biology
Growth Rate
Survival Rate
Behavior
Feeding Rate
Anthropophily
Physiology
Vector Competence
Arthropod Vector
Aspects
Malaria System
Anopheles mosquitoes are mostly tropical but
ranges are expanding with warming climates.
Anopheles populations can increase 100X in 14
days!
A small percentage of long-lived, multiple-biting
females can comprise a large proportion of the
infective vector population. The ability to bite more
than once is of paramount importance in disease
transmission.
Some species of Anopheles prefer to bite humans;
many breed in urban environments.
Anopheles mosquitoes are resistant to the effects of the
parasite, and parasite can reproduce in the vector.
Generally, epidemics follow sharp increases in
vector numbers following rains &/or warm
weather.

50. • Most important human
disease
(now matched by AIDS)
•Taxonomic and geographical
range of potential vectors is
increasing with increased
human mobility and global
warming.
• Resistance to treatments
increasing in parasite;
search
for a vaccine continues.
Important Points

51. INTERMEDIATE HOST
 Wuchereria bancrofti is
transmitted by Culex, Aedes, and
Anopheles species
 Brugiamalayi is transmitted by
Anopheles and Mansonia species.
Anopheles
Aedes
CulexMansonia

52. FLESH FLIES SARCOPHAGIDAE
Myiasis - disease caused by parasitic
dipterous fly larvae feeding on the
host’s tissue (primary and secondary)

53. NASAL MYIASIS ISN´T A FREQUENT PATHOLOGY AND HAPPEN MAINLY IN
DEVELOPING COUNTRIES

54. PATIENT WITH DESTRUCTIVE RHINO-ORBITAL MYIASIS

57. GASTEROPHILUS INTESTINALIS (LIII)
HYPODERMA BOVIS (LIII)

58. HOUSE FLY MUSCA DOMESTICA
 enteric diseases transmitted by fly,
connected with faecal contamination -
typhoid fever, cholera, polio, hepatitis,
salmonellosis etc.
 tuberculosis
 Ascaris spp.

59. FORENSIC ENTOMOLOGY
Human corp after death can be successively
decomposed by various insects. The “age” of corp
can be estimated by presence of definite insect
species, climatic conditions should be considered.
Skinbeetles etc.Blowflies atc. Carrion beetles etc

60.  MDT is the introduction of disinfected green bottle fly
maggots or larvae into the non-healing skin and soft tissue
wound(s) of a human for the purpose of selectively cleaning
out only the necrotic (dead) tissue and promote healing.
 larvae that feed on dead tissue can clean wounds and may
reduce bacterial activity and the chance of a secondary
infection
 larvae dissolve dead tissue by secreting digestive enzymes
onto the wound as well as actively eat the dead tissue
 Lately maggots have been making a comeback due to the
increased resistance of bacteria to antibiotics