This document discusses medical entomology, which deals with arthropods that affect human and animal health. It describes how insects can transmit diseases, inject venom, and cause irritation. Mosquitoes and ticks are responsible for transmitting many vector-borne diseases. Malaria, in particular, has had huge impacts on human history. The document outlines the life cycles of important disease vectors like mosquitoes, sand flies, black flies, triatomine bugs, fleas, lice, and tsetse flies. It also discusses the diseases they transmit, including malaria, dengue, plague, Chagas disease, sleeping sickness, and river blindness. Vector control methods like larviciding and using larvivorous fish are also mentioned.

3.  Entomology: It is a science that deals with the study of
arthropods in general, and incorporates sciences like zoology,
biology, parasitology and micro-biology.
 Medical entomology: Branch of entomology which deals
with arthropods which affect the health and well-being of man
and vertebrate animals.
 In other words, medical entomology is the medical science
directly concerned with vectors that affect human and animal
health.

4.  Insects have huge impact on
health of humans & domestic
animals
 Irritation & diseases
 Transmit diseases (vectors)
 Inject venoms & transmit
allergens
 Cause wounds
 Create nuisance & phobias
Leishmaniasis
Myiasis

5. • Mosquitoes and ticks account for the majority of
transmissions of the most important vector-borne diseases,
although some close relatives of mosquitoes also get
involved, including sand flies and black flies
 Alexander the Great, conqueror of many nations, was
vanquished by the bite of a tiny mosquito bearing malaria
parasites
 The Black Death, decimator of Europe, killer of tens of
millions worldwide is the work of a tiny flea vectoring the
bacilli that cause bubonic plague from rats to people.

6.  Malaria: 4-5million cases/year
 236 million and 5 million people living in filaria and guinea
worm disease endemic areas respectively
 Scabies widespread especially in rural areas
 Prevalence of trachoma 0.5% in West Bengal to 79% in
Punjab and Haryana

8. Transmission of Arthropod borne
diseases
TransmissionsTransmissions
Direct Contact
From man to man
Scabies
pediculosis
Direct Contact
From man to man
Scabies
pediculosis
Mechanical
Diarrhea
Dysentery
Typhoid
Trachoma
Mechanical
Diarrhea
Dysentery
Typhoid
Trachoma
BiologicalBiological
Propagative
Only multiplication
No developmental
Plague bacilli in rat
flea
Propagative
Only multiplication
No developmental
Plague bacilli in rat
flea
Cyclo-propagative
Multiplication
developmental
Malaria parasites in
mosquito
Cyclo-propagative
Multiplication
developmental
Malaria parasites in
mosquito
Cyclo-developmental
No multiplication
developmental
Filaria parasite
in mosquito,
Guineaworm in cyclops
Cyclo-developmental
No multiplication
developmental
Filaria parasite
in mosquito,
Guineaworm in cyclops

9. Trans-ovarian/ Trans-stadial transmission:
•the causative agent is transmitted to the immature stage (usually
to the egg) from the adult insects and / or other arthropods which
carry disease pathogens.
•e.g Ticks and sand flies
Pathogens transferred by arthropods
 Viruses (arboviruses)
 Bacteria (also rickettsias)
 Protozoan parasites
 Filarial nematode worms

10.  Biologically transferred diseases
 Parasites have single or secondary cycles
 Single cycle : Pathogen completes life cycle only within
vector & human host. e.g Human malaria
 Secondary cycle : Pathogen completes life cycle within
vector & animal or human host
 Non-human vertebrates are primary hosts
▪ Monkeys (yellow fever); rats (plague); desert rodents
(leishmaniasis) etc

11.  Origin from musca(latin)
Mosca (portugese)
 Mosquito (spanish) Macchara
( hindi)
 There are about 3000 species
of mosquito, of which about
100 are vectors of human
diseases
 Worldwide,
 380 species of Anopheles,
950 species of Aedes and
 550 species of Culex

13. Anopheles Culex
Aedes
Mansonia

17. Malaria cycle

18. EGG Anopheles Aedes Culex Mansonia
Laying On water surface Above or near
water surface
On water surface Attached to
undersurface of
leaves (pistia)
Hatching time 2-3 days 2-3 days 2-3 days 2-3 days
Position Float Float Float Float
Number Single Single Rafts of 100 or
more eggs
Cluster
Shape Boat shaped,
paired lateral
floats, elongated
Cigar shaped - Star shaped
cluster

19. Larva Anopheles Aedes Culex Mansonia
Float Horizontally Suspended Suspended Suspended
Siphon tube - + + +, attached to
rootlets
Life 2 days 5-7 days 5-7 days 5-7 days
Pupa
Shape Comma shaped Comma shaped Comma shaped Comma shaped
Siphon tube Short and broad Long and narrow Long and narrow Long and narrow
Life 1-2 days 1-2 days 1-2 days 1-2 days
Adult
Life 4 weeks 3 weeks 4 weeks 4 weeks
Resting position Inclined 45* Hunch back Hunch back Hunch back
Wings Spotted Unspotted Unspotted Unspotted
Palpi Long in both sex Short in female Short in female Short in female
Noise - + + +

21. Habits Anopheles Culex Aedes Mansonia
Feed on Anthropophilic
and zoophilic
Anthropophilic Anthropophilic Anthropophilic
Biting time Evening or early
part of night
Midnight Day biters Night
Feeding place Indoor Outdoors In and around
houses
Outdoors
Resting place Indoor rester-
cattle sheds and
human dwellings
Outdoors Dark and quit
places,
bedrooms,
kitchen
Outdoors
Breeding place Clean water,
ponds, pools,
lakes,
Spring, overhead
tanks
Dirty water
collections,
stagnant drains
Cesspools
Septic tanks
Burrow pits
Artificial
accumulation of
water, tyres,
Broken glasses
Aquatic plants
Flight 0.75-1 km 11 km <100 m 1 km

23. 23
Culex

24. 24
Aedes

25. Mansonia

26.  Anopheles 45 species in India
 7 are vectors of malaria
1) An. Culicifacies:
 It is most important vector in malaria transmission in India & very widely
distributed in RURAL area of North, South and Central India
2) An. Stephensi: it is normally vector for URBAN area, particularly in
coastal region.
3) An. Minimus: in N.E. states, North West Bengal
4) An. Fluviatilis: seen along Himalaya range seepage and in irrigation
channels.
5) An. Dirus: deep forest in N.E. region.
6) An. Sundaicus: Andaman and Nicobar Island
7) An. Philippinensis: is the vector for the plains of West Bengal and N.E.
region.

31. FILARIASIS

33.  Malarial vector indices
1. Human blood index =
proportion of freshly fed female
anopheles showing human blood
in their stomach
2. Sporozoite rate = % of female
anopheles having sporozoites in
their salivary glands
3. Mosquito density = no. of
mosquitoes/ man hour catch
4. Man biting rate = avg.
incidence of anopheles bite/
day/hr
 Larval surveys of Dengue
 House index = % of house
infected with larva/pupae
 Container index = % water
holding containers infested with
larva/pupae
 Breateau index = no. of +ve
container/100 houses inspected
 Pupae index = no. of pupae/100
houses inspected

34. 1. PERSONAL PROPHALATIC MEASURES
Use of mosquito repellent creams, liquids, coils, mats etc.
Wearing of full sleeve shirts and full pants with socks
Use of bednets for sleeping infants and young children during
day time to prevent mosquito bite 2.
BIOLOGICAL CONTROL
Use of larvivorous fishes in ornamental tanks, fountains, etc.
Use of biocides
3. CHEMICAL CONTROL
Use of chemical larvicides like abate in big breeding containers
Aerosol space spray during day time

35.  Larvivorous Fish
Advantages
 Environmental friendly
 Easy to introduce
 Self propagating & self sustainable
 User friendly
 Helps build community participation &
intersectoral collaboration
 Cost-Effective - no recurrent costs
Limitations
• Extremes of temperatures and pollution
• Suitable for some types of breeding sources only
• Needs proper planning with mapping of breeding
sources & promotional efforts
Lebister reticulatus
Gambusia affinis
Aphanius dispar
• Biolarvicide: Bacillus thuringiensis
iserailensis (Bti)-Endotoxin : 2.5%
suspension, 1 lit/50 m2, once every 2
weeks.

36. 4. ENVIRONMENTAL MANAGEMENT & SOURCE
REDUCTION METHODS
•Detection & elimination of mosquito breeding sources
•Management of roof tops, sunshades
•Proper covering of stored water
•Reliable water supply
•Observation of weekly dry day
5. HEALTH EDUCATION
•Impart knowledge to common people regarding the disease and vector
through various media sources like T.v., Radio,
•Cinema slides, etc.
6. COMMUNITY PARTICIPATION
•Sensitilizing and involving the community for detection of Aedes
breeding places and their elimination

37.  Species
 Phlebotomous argentipes
(kala azar)
 P. papatasii (sandfly fever,
oriental fever)
 P. sergenti (oriental fever)
 Sergentomyia punjabensis
(sandfly fever)
 Transmit
 Protozoa (leishmaniasis)
 Arboviruses (pappatassi
fever)
 Bacteria (oroya fever)
Eggs Laid in Damp
and dark
places
Torpedo
shaped
longitudinal
wavy lines
Hatch in 7
days
Larva 2 weeks
Pupa 1 week
Adult avg life 2 weeks

38. Identification
 Small cryptic flies (2-4 mm)
 Very broad & hairy wings with
long parallel veins, lanceolate
shaped
 Wings held open over body
 Adults hide in rat burrows during
day; enter houses at night to feed
 Adults & larvae live near water
 Larvae live in moist soil or in
cracks & crevices where they
survive on condensed water

39. KALA AZAR

40.  Identification
 Thorax dark longitudinal
striped
 Mostly based on presence or
absence of bristles on thorax
 Tenent hairs secrete sticky
substance
 Biology
 Larvae live in various types of
organic matter; manure,
garbage, rotting vegetation
 Nuisance flies
 Mechanical disease transmitters

41. Mode of transmission
1.Mechanical : also called as
Porters of infection
2.Vomit drop
3.Defecation
Egg laid 120 -150
Colour Pearly white,
1mm long
Hatching time 8-24 hrs,
in summer 3 hrs
Larva(maggot) White 2-7 days
Pupa Dark brown,
barrel shaped
3-6 days
Adult 15 days (summer)
25 days(winter)
Life cycle 5-6 days (summer),
8-20 days(winter)
Breeding place Human excreta,
manure of animals,
garbage
Feeding habits Sputum, feaces,
discharges from
wound, open sores
Resting habits Rest on vertical
surfaces, hanging
objects
Dispersal Upto 4 miles
– mechanically transfer
bacteria & viruses
• Cholera, poliomyelitis,
leprosy, typhoid fever,
dysentery etc

42.  Identification
 Small (2-5 mm) stocky
grey-black flies
 Humped thorax (buffalo
gnats)
 Clear wings without
hairs or scales

43.  Eggs laid on submerged stones
and water weeds
 Aquatic larvae live in fastest
flowing parts of streams & rivers
 Larvae attach to rocks &
vegetation (via silk & hooks)
 Larvae are filter-feeders using
complex labral fans on head (3-4
wks)
 Pupate on rocks underwater (1-3
wks)
 Adults may occur several
km(100 miles) from water
Head fans
Aquatic larva

44.  Females are blood-feeders
 Simulium indicum in India
 Vicious biters & cause major
distress to poultry, livestock &
humans
 Cause extreme pain, itching &
local tissue swelling
 Vast swarms cause livestock
deaths via blood loss, suffocation
& trauma
 In tropical Africa Simulium
damnosum transmit filarial
worms that cause river
blindness (onchocerciasis) in
humans
 Also transmit filarial worms,
trypanosomes disease in poultry

45.  Found only in African continent
 Regions affected with tsetse flies
are called ‘fly belt’
 Single genus (Glossina)
 29 species & subspecies groups
 Both sexes are host-specific
blood-suckers (bites are painful)
 Transmit protozoans
(trypanosomes gambiens)
▪ Sleeping sickness/
trypanosomiasis (humans)
Tsetse bite

46.  Identification
▪ Large robust bugs, ambush
predators of arthropods
▪ Strong recurved beak for biting
Inject paralytic toxin to subdue
▪ Live in woodland & forest habitats
▪ Colonized human dwellings
▪ Live in ceilings, cracks & crevices
etc.
▪ Attack humans at night
▪ Most notorious species are
Triatoma infestans & Rhodnius
prolixus prey

47.  Medical importance
Bites very painful to humans, may
cause intense itching, nausea, flushed
face, palpitation
Mexico , central and South American
subfamily Triatominae (kissing bugs)
feed on human & animal blood and
spread protozoans (trypanosoma
cruzi) which cause Chagas’s disease
(American trypanosomiasis)
Triatoma infestans
Rhodnius prolixus

48.  Pthiridae (crab lice, pubic lice)
 Broad, flat lice that appear crab-
like
 Mid & hind legs are stout with
very large claws
 Abdominal segments have
distinct lateral lobes
 Single species (Pthirus pubis)
confined to human pubic region
▪ Bites cause irritation & typical
rash
▪ Spread by close body contact
(usually sex)
▪ No diseases transmitted
Crab louse
Rash caused by infestation

49.  Biology
 Entire life cycle occurs on host
 Eggs (nits) are cemented onto host’s
hair or feathers
 All stages (nymphs & adults are
blood sucking
 Transmission via contact between
hosts
 Unable to survive for long when off
hosts
 Many species are host specific
▪ Attack one or few related species
▪ Live in specific region of host’s body
▪ Identity often indicated by host
▪ Only 3 species attack humams
Louse nit
Adults & nymphs

50.  Pediculidae (human lice)
 Elongated lice with abdomen
longer & wider than thorax (no
lateral projections)
 All 6 legs are equally strong &
developed with claws
 2 species (also called subspecies)
▪ Pediculus humanus (body louse)
▪ Pediculus capitis (head louse)
▪ Very similar but differ in habits
▪ Bite severely and Annoying pests
▪ Infestation is called as pediculosis.
Head louse
Body louse

51.  Head lice
 Suck blood from scalp & lay eggs on hair
 Common & easily spread by close contact,
sharing of combs, brushes, hats etc
 Body lice
 Suck blood from body & lay eggs on
clothing
 Uncommon & spread by bodily contact,
sharing of clothing or bedding
 Vector diseases (epidemic typhus,
trench fever, relapsing fever)
 dermatitis
 Lousiness related to sanitation
 Crowded conditions
 Long periods without bathing or changing
clothes
Nits on human hair

52.  37 species in India
 Small, laterally flattened, wingless
insects
 Large hind legs & spectacular
jumps
 Parasitic on birds & mammals
 Many pest species occur
worldwide
▪ Cat flea (Ctenocephalides
felis)
▪ Dog flea (Ctenocephalides
canis)
▪ Human flea (Pulex irritans)
▪ Oriental rat flea
(Xenopsylla cheopis)

53.  Rat fleas (oriental)-
murine typhus/ bubonic plague
 Xenopsylla cheopis
 X. astia
 X. braziliensis
 Rat fleas(temperate)
 Nosopsylla fasciatus

54.  Mode of transmission
 Biting( mainly in plague) blocked flea
bites due to multiplication of plague
bacteria in proventricularis and blocking it
 Mechanical
 Feces
 Flea index
 General flea index= avg no. of all species/
rodent
 Specific flea index= avg no. of each
species/rodent
 Percentage incidence of flea species= %
of fleas of each species/ rodent
 Rodent infestation rate= % of rodents
infested with various flea species
Oriental rat flea

55. 1. TICKS
Soft Ticks
(Ornithodorus/argasidae)
Hard Ticks (Ixodes,
Amblyomma, Rhipicephalus,
Dermacentor)
2. MITES
(Dematophagoides, Demodex,
Sarcoptes)
•
General Characteristics
-tough leathery integument
-flattened oval shape when
examined dorsally
-Four pair of legs
-No antennae

56. Disease
 Soft Ticks :
 Tick borne relapsing fever (Borrelia duttoni)
 Rickettsial disease (Coxiella burneti), and some
arboviruses
 Hard tick :
1. Dermacentor and Amblyomma-
Rocky Mountain Spotted Fever
(Rickettsia rickettsia)
2. Dermacentor - heamorrhagic fevers.
 Tularaemia,
 Mediterranean Spotted Fever
 African Tick Typhus

57.  Lindane lotion is the treatment
of choice, permethrin is another
alternative
 Ivermectin has been
recommended for Norwegian
scabies
 Malathion liquid can also be
used, benzyl benzoate is also
active
 Normal laundering of bed linen
and clothes is recommended
 Household and sexual contacts
should also be treated

58.  Fresh water
 Pear shaped
semi transparent
body
 Avg life 3 months
 Diseases: acts as
intermediate host for:
1. Guinea worm disease
(dracontiasis)
2. Fish tape worm
(diphyllobothrium latum)

59. 1 Mosquito Malaria, Filaria, JE, Dengue Fever, Chikungunya
2 Housefly Typhoid, Cholera, Diarrhea & Dysentery,
Poliomyelitis, Gastroenteritis, Trachoma
3 Itch Mite Scabies
4 Cyclops Guinea worm disease
5 Sand fly Kala-azar, Oriental sore, Sandfly fever
6 Tsetse fly Sleeping sickness
7 Louse Epidemic Typhus, Relapsing fever, Pediculosis
8 Rat flea Bubonic Plague, Chiggerosis, Endemic typhus
9 Reduviid bug Chagas disease
10 Hard tick Tick typhus, Viral encephalitis
11 Soft Tick Q fever, Relapsing fever
12 Trombiculid mite Scrub typhus, Rickettsial pox