Veterinary entomoloy/ Parasitology/ Para-301

1. VETERINARY ENTOMOLOGY

2. Definition
•Study of insects that cause disease or that are vectors of
organisms that cause disease in animals.

3. What is Acarology?
•Study of arachnids that cause disease or act as vector
of disease

4. WHAT IS ARTHROPODA
• IT IS GROUP OF INVERTEBRATE ANIMALS WHICH HAVE
JOINTED LEGS

6. JOINTED LEGS

7. WHAT IS ENTOMOLOGY?
• IT IS STUDY OF INSECTS

8. Why to study this subject?
• Insects produce multiple damages to livestock animals
• They reduce egg, milk, and meat production
• They damage hides
• They transmit dangerous diseases from animal to animal and from animal
to humans
•

9. BRANCHES OF ENTOMOLOGY
MEDICAL
• ENTOMOLOGY
AGRICULTURE
• ENTOMOLOGY
VETERINARY
• ENTOMOLOGY

10. WHAT ARE INSECTS
• Invertebrate animals with 6 legs are called insects
•

11. Characters
• Insects have following main characters
• Head
• Thorax
• abdomen

13. Head
• It bears
• A pair of antennae
• Pair of eyes
• Mouth parts

14. Antennae
• They are sensory organs

15. Eyes
2 types
Simple
Compound

16. • An other term for Simple Eye
What is Ocelli

17. Simple eyes
• Eyes with single lens

18. Compound eyes
• Cluster of many simple eyes

19. Compound Eye

20. Do all insects have eyes
• No, some insects are blind
• E.g. Lice

21. Do All insects have compound eyes?
• Yes

22. Mouth parts

25. Chewing
• Examples of chewing insects include dragonflies, grasshoppers and beetles

26. Piercing

27. Thorax
• It is second par after head

28. What is in thorax
• 3 Segments
• Proto-thorax
• Meso-thorax
• Meta -thorax

29. Why Study the Insect Thorax?
• • Structure determines how an insect moves
• through its habitat.
• • Wings determine flight capability
• • Legs determine how it moves and digs on
• land

30. Insects and their relatives are hexapods, having six legs, connected to the
thorax, each with five components.

35. Thanks

45. Insect Parthenogenesis (Virgin Birth)

47. Molting

48. Ecdysis

49. Instar

50. DR. A.G. ARIJO

51. DR. A.G. ARIJO

52. Classification
•
Scientific name: Musca domestica
• Lifespan: Male: 28 days (In High Temperature, Low activity, Adult)
• Order: Fly
• Rank: Species
• Phylum: Arthropoda
• Higher classification: Musca

53. Feeding
Suck the fluids from wound
DR. A.G. ARIJO

54. ADULT FLY
•2 wings
•4 black stripes on the
thorax
•The adult is 1/4" long.
DR. A.G. ARIJO

55. What is their life cycle?
• 7-10 days under ideal conditions.
DR. A.G. ARIJO

56. Eggs
• 2,700 eggs in 30 days
• 350-900 in 5 or 6 batches.
• Eggs appear in clusters
• Hatch in 6 to 24 hours.
DR. A.G. ARIJO

57. • Larva is out in 24 hours
• The pupal stage lasts 3-6 days.
• The adult female is ready to lay eggs 2 2 days after emergence and
continues to lay eggs for about one month.
DR. A.G. ARIJO

59. LIFE SPAN
• Adult flies live from 30-60 days during warmer months.
DR. A.G. ARIJO

60. LIFE CYCLE
• EGGS
• The eggs are white, elongate and about 1/20" long
DR. A.G. ARIJO

61. LARVA
• Also called maggot.
• It is creamy white color.
• Maggots have no legs
• Carrot shaped.
• Two breathing holes at the hind end
• They're about 2/5" long
DR. A.G. ARIJO

62. PUPA
• The pupa are reddish-brown in color. They are barrel-shaped
and about 3/8" long. Pupal cases are sometimes mistaken for
cockroach egg capsules.
DR. A.G. ARIJO

63. Where are they found and how do
they develop?
• Homes
• Restaurants
• Animal houses
• Dead animals
DR. A.G. ARIJO

64. • Animal and human manure
• Garbage or decaying meat.
• They can readily breed in fresh and wet garbage.
DR. A.G. ARIJO

65. • They may also breed in wet flour and soybean meal around industrial
plants. As many as 868 pupa can develop from 1 ounce of manure.
DR. A.G. ARIJO

66. DISTRIBUTION
• WORLDWIDE
DR. A.G. ARIJO

67. Do they bite?
• Adult house flies do not bite. They have sponging mouthparts for
feeding.
DR. A.G. ARIJO

68. Do they carry disease?
• Houseflies are a danger to the health of man and animals principally
because it carries and spreads disease organisms.
• They move from garbage and sewage to our dinner plates.
• It carries bacteria on the outside of its body, it regurgitates saliva and
deposits wastes on human food.
DR. A.G. ARIJO

69. KEY FACTS
•The average house fly lives on average 21 days.
•A flies wings beat 200 times per second.
•Flies don't grow. They are born full size.
•Flies have 4000 lenses in each eye.
•Flies jump up and backwards when taking off.
•Average speed of a fly in flight is 4.5 m.p.h..
•Flies smell with their antennae
•
DR. A.G. ARIJO

70. DR. A.G. ARIJO

71. COMPLETE METAMORHOSIS
DR. A.G. ARIJO

72. CARRIER OF FUNGAL DISEASE
DR. A.G. ARIJO

73. ROLE AS VECTOR
DR. A.G. ARIJO

74. Mastitis
•Mastitis
DR. A.G. ARIJO

75. Conjunctivitis or Pink eyes
DR. A.G. ARIJO

76. Anthrax
DR. A.G. ARIJO

77. Raillietina
DR. A.G. ARIJO

78. Skin lesions
DR. A.G. ARIJO

79. Eye worm
DR. A.G. ARIJO

80. DR. A.G. ARIJO

81. Chemical control
DR. A.G. ARIJO

82. Biological control
DR. A.G. ARIJO

83. DR. A.G. ARIJO

84. DR. A.G. ARIJO

86. MEDICAL ENTOMOLOGY
OVERVIEW
• Definition
• History
• Intro to Arthropods and Insects
• Intro toVector-Borne Disease Concepts

87. MEDICAL ENTOMOLOGY - the study of diseases caused by arthropods
• public health entomology - arthropods and human health
• veterinary entomology - arthropods and pets, livestock and wildlife
These fields of study are linked by the ecology of most
arthropod transmitted pathogens and parasites.

88. Arthropods affect the health and well-
being of humans and animals in
several ways:
• Direct Causes of Disease or Distress
• Vectors or Hosts of Pathogenic
Organisms
• Natural Enemies of other medically
harmful insects

89. Direct Causes of Disease or
Distress:
• Ectoparasites - ticks, fleas, mites
• Endoparasites - chigoe flea, myiasis
• Envenomization - wasps, bees, spiders
• Allergic Reactions - dust mites
• Annoyance - mosquitoes, black flies
• Delusory parasitosis (DP) - psychosis

90. Vectors or Hosts of Pathogenic Organisms:
• Arthropod serves as intermediate host
and vector of pathogenic
microorganisms
• Vectors and hosts - bloodfeeding
• Hosts only - no bloodfeeding

91. Natural Enemies of other medically
harmful insects:
• Mites parasitic on mosquitoes
• Fire ants consume tick eggs

92. History of Medical Entomology:
• References to associations between
humans and arthropods – historical
(Homer and Aristotle, among others, wrote about the nuisance
caused by flies, mosquitoes, lice and/or bedbugs.)
• Important discoveries:
• Microscope - Leeuwenhoek 1700’s
• Infectious Disease - Koch et al. 1800’s

93. History of Medical Entomology - 2:
• Mosquitoes (Culex pipiens) and filarial worms
(Wuchereria bancrofti) - Manson, 1877
• Tick (Boophilus annulatus) and Texas cattle fever
(piroplasmosis) transmission - Smith & Kilborne,
1891
• Mosquito (Aedes aegypti) and yellow fever virus -
Finlay, Reed, Carroll, Agramonte and Lazear, 1900
• Trypanosomes in cattle blood - Bruce, 1895
• Tsetse fly (Glossina sp.) transmission of
trypanosomes - Bruce, 1896
• Tsetse fly transmission of trypanosomes to

94. History of Medical Entomology - 3:
• Malaria parasites in human blood - Laveran,
1894
• Anopheles mosquitoes with malaria parasites -
Ross, 1897
• Transmission of bird malaria by Culex
mosquitoes - Ross, 1898
• Complete development of human malaria
parasite in mosquitoes - Grassi, 1898
• Transmission of human malarial parasite by
mosquitoes - Sambon and Low, 1899
• Only Anopheles mosquitoes transmit human

95. History of Medical Entomology - 4:
• Mosquito transmission of dengue virus - Graham,
1902
• Fleas and plague - Liston, Verjbitski et al.,
1895 - 1910
• Triatomine bugs and trypanosomes (Chagas
disease) - Chagas, 1908
• Black flies and onchocerciasis (river blindness) -
Blalock, 1926
• Mosquitoes and viral encephalitides - Hammon and
Reeves, early 1940’s
• Ticks and Lyme disease - Spielman, early 1960’s

96. Arthropods and Insects
Characteristics

97. Phylum Arthropoda:
• The phylum is probably monophyletic, but with 4
distinct groups.
• It includes lobsters, crabs, shrimp, centipedes,
millipedes, daddy longlegs, insects, ticks, and
mites, and spiders.
• There are over 1 million species of arthropods,
making up the largest phylum in the animal
kingdom.
Taxonomy and Systematics

98. Phylum Arthropoda - 2:
• Metameric - (body exhibits true segmentation -
replication of muscles and nerves)
• Tagmatosis - (segments of the body are modified
and grouped together to form mouthparts and body
regions such as the thorax)
• Chitinous exoskeleton – nitrogenous
polysaccharide

99. Phylum Arthropoda - 3:
• Bilaterally symmetrical
• Jointed legs
• Dorsal heart – open circulatory system
• CNS (organized central nervous system)
• Striated muscle

100. Hypothetical Insect Evolution
“Worm-like” ancestor
Metamerism
(true segmentation)
Tagmatosis
(segments modified
and grouped together
to form larger body
parts)

101. Phylum Arthropoda
Class Crustacea - lobsters, crabs, etc.
Class Chelicerata - spiders, mites, ticks,
scorpions, etc.
Class Diplopoda - millipedes
Class Chilopoda - centipedes
Class Insecta - beetles, flies, moths, etc.

103. Insect Characteristics
THREE distinct body regions:
• Head (feeding, sensory, CNS)
• Thorax (locomotion, respiration)
• Abdomen (feeding, reproduction)

104. Typical Insect Integument

105. General Insect Structure

106. General Insect Head

107. Cricket Mouthparts
Dissected
Grasshopper Mouthparts

108. Insect Thorax

109. Insect Abdomen

110. Insect Antennae

111. Piercing Sucking
Mouthparts

112. Insect nervous system

113. Insect Endocrine Regulated Process

114. Insect Alimentary Canal

115. Insect Circulatory System

116. Insect thorax showing tracheal branches

117. female
male
Insect Reproductive System

118. Cross Section of Unfed Mosquito
Head Thorax Abdomen

119. Bloodfed Mosquito
Thorax Abdomen

120. Gravid Mosquito
Head Thorax Abdomen

121. Types of Insect
Development
“A” – (lacking)
“Hemi” -(incomplete)
“Holo” -(complete)

122. Other Medically Important
Arthropods (non-insects)

123. Mite external anatomy

124. Tick internal anatomy

125. Mouthparts
Why are these
important?!!!

126. Apis (honeybee) mouthparts

127. Housefly mouthparts

128. Anopheles (mosquito) mouthparts

129. Concepts in Vector-Borne Disease

130. Transmission efficiency:
• Geographic or host distribution of the parasite
• Incidence of any given parasite and associated host
• Parasite enhancement of transmission
Transmission frequency:
• Shorter life cycle of parasite = more frequent and more
efficient transfer to be successful
Both transmission efficiency and frequency related to
bloodfeeding frequency and efficiency of the vector. These are
important factors in vector capacity.

131. Host:
• reservoir host
• disseminating host
• dead-end (aberrant) host

132. Vector:
• primary vector
• secondary vector
• maintenance vector

133. Vector Biting Activity:
• nocturnal
• diurnal
• crepuscular

134. Host specificity (blood meal source):
• anthropophilic
• anthropophagous
• ornithophilic
• ornithophagous
• zoophilic
Feeding location:
• exophilic
• endophilic

135. Incubation periods:
• extrinsic incubation period
(in arthropod vector)
• intrinsic incubation period
(in vertebrate host)

136. Autogeny vs. Anautogeny
Number of blood meals:
• ovarian scar/blood meal
• parity status
Determines:
• age of vector
• blood feeding aggressiveness
• vector importance

137. Types of pathogen transmission:
• mechanical
• biological

138. Biological:
•propagative
•cyclopropagative
•cyclodevelopmental

139. Pathways of biological pathogen transmission:
Vertical transmission:
•transovarial transmission
Horizontal transmission:
•venereal transmission
•transstadial transmission

140. Intrinsic barriers to transmission in the vector -
(genetically and environmentally controlled)
• midgut infection, midgut escape
• salivary gland infection, salivary gland escape
• insect immune response, parasite encapsulation

141. Vector competence vs. vector capacity
Capacity can be measured in the field using components of number of vectors
per human, number of human bloodmeals per day per vector, daily survival rate, and the
extrinsic incubation rate of pathogen; vector efficiency is expressed in terms of low -
high capacity
Competence can be expressed in the laboratory, but a competent lab vector is
not necessarily important in disease transmission in the field.

143. SUMMARY
• Overview of Medical Entomology
• Definition
• History
• Intro to Arthropods and Insects
• Intro to Vector-Borne Disease Concepts