Download Medical and Veterinary Entomology

Dr. Ghada M. El-Bassiony
Ass. Professor
Department of Entomology
Medical Entomology
Can be defined as the study of insects, insectborne disease and other associated problems that
affect human and public health
Veterinary Entomology
Can be defined as the study of insects, insectborne disease and other associated problems that
affect domestic animals.
 Medical-veterinary
arachnology
 Medical-veterinary acarology
 Insect-borne diseases of human influenced
human history (yellow fever, plague, louseborne typhus)
 Also arthropods have greatly influenced
animal production and husbandry practices
 The
insect or arthropod, with any medical
importance, may be one of the three following
cases:



1- the causal agents themselves or the pathogens
(scabies & pediculosis)
2- the vector of pathogens (malaria)
3- developmental transfer hosts (for some
helminthes parasites)
 Zoogeographical

regions
It’s useful to be able to describe the distribution of
an insect or a disease by reference to these regions
rather than national boundaries and names.
The World Wide Fund for Nature (WWF): is an
international non-governmental organization founded on
April 29, 1961, and is working on issues regarding the
conservation, research and restoration of environment.
 Modes
of transmission
Vertical transmission:
parasites transmit by vectors within vector populations
 1- transstadial transmission: sequential passage of
parasites acquired during one life stadium to the
next (mites &hard ticks) e.g. lime disease,
spirochetes
 2- transgenerational transmission: occurs
transovarially - parasites infect the ovarian germinal
tissues
 3- ventral transmission (La Cross virus by A.
triseriatus)

 Horizontal
transmission:
represents the role of the arthropod in
the life cycle of the parasite
transmission
 2- biological transmission
 Propagation or multiplication
 Cyclo-propagation
 Cyclo-developmental without propagation

1- mechanical

Differences between biological and mechanical
transmission
1- duration of the vector infectivity
 2- character of the pathogen not the insect vectors

The pathogen
the vertebrate host
insect
vector
ex: (malaria)
Many diseases have a forth component
reservoir host
 Several
Biting Flies and Reduviid Bugs carry
infective stages of disease causing
pathogens. They are responsible for
spreading diseases like:




Malaria (Mosquitoes in genus Anopholes)
Plague (Rodent Fleas)
West Nile Virus (Mosquitoes)
Typhoid/Cholera/Dysentary (Muscid Flies)
Medical importance
of cockroaches
As vectors
1- Blattela germanica
Acquire specific bacteria
and depositing it on food
2- they may be chronic
carriers.
3- experimentally they can
harbor pathogens.
As developmental hosts
of parasites
1- eye worm of poultry
2- the nematoda
Spirura gastrophiala of rats
3- the nematoda
Gongylonema neoplasticum
of rats
As allergy cause
Extracts give positive skin
test in allergic patients
and normal persons
 Adult
moths may feed
on lachrymal
secretions of wild or
domestic mammels.
 If the proboscis is
contaminated with
pathogenic bacteria,
mechanical
transmission may
occur.
 Larvae may produce
allergens.
Mechanical vectors
Carry pathogens on
their bodies or their
digestive tract or moth
parts
 May carry dysentery
germs or may
contaminate surgical
objects with bacteria
As developmental hosts of
parasites


Formica serve as a second
developmental host of
little liver fluke of sheep
(a trematode), the first
being a snail.
 Making
food inaccessible in case of pests
ants.
 Isolation of sterile materials.
 Using toxic baits.
 JHA
 Pesticides
Order Coleoptera
 Adults
feed on
decaying organic
matter or on plants
 May be found on
vegetation during
the day
 Attracted to bright,
white light at night
A- Some beetles secrete cantharidin
(e.g. blister beetles)
 Hemolymph contains compounds
that cause a vesicating dermatitis
on contact with the skin
 Resulting blisters are painful, but
do not require emergency
treatment
 Contact with eyes may result in
severe debilitation
 Large numbers of cases may
occur at the same time
 Sometimes mistaken for chemical
agent injury
B- canthariasis and
scarabiasis
--------------------------Invasion of body tissues
by beetles larvae or
adults
Most clinical cases involve enteric
canthariasis.
C. Annoyance by beetles
A- ingestion of toxic
beetles
------------------------Horses that ingest
quantities of these
beetles are
especially
susceptible to
cantharidin
poisoning.
B. mechanical vectors
of animal
pathogens.
C- intermediate hosts
of parasites like
cestodes,
trematodes and
nematodes.
 Immediate
wash skin surface
 Proper wearing of the uniform in vegetation and
at night around lights
 If one lands on you, blow it off, don't crush it
 Pesticides out doors and are most beneficial
when applied to soil