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Introduction-to-Parasitology Powered By Docstoc
					         Introduction to Parasitology
Definition of Parasitology:
Each animal is a host of many parasites; thus, there are far more
parasitic organisms on earth than there are non-parasitic organisms.

In this course we will concentrate on 3 major groups of parasites:
1. ____________________- flagellates, amebae, malarial organisms
2. ____________________ - parasitic worms such as the flukes,
tapeworms,and roundworms
3. ____________________ - insects and arachnids that are
ectoparasites and carriers (___________________) of diseases
       Why do we study parasites?

1. __________________________________________
  •   parasites provide unique examples of biological
      phenomena not found in free-living organisms

2. __________________________________________
  •   Medical importance
  •   Veterinary importance
  •   Economic importance
              Medical Importance of Parasites
Humans are hosts to over ___________ species of parasites.
Many of these parasites are causative agents of major public health problems of
the world. Recent estimates of prevalence of parasites in the world are:
   Disease Category                    # Human Infections   Deaths per year
   Roundworm Ascaris lumbricoides      1.2 billion          60,000
   Whipworm Trichuris trichiura        795 million          10,000
   Hookworms                           740 million          65,000
   Filarial worms                      657 million          20,000 to 50,000
   Malaria                             300- 660 million     1-2 million
   Schistosomes                        200 million          20 million
   Ameba Entamoeba histolytica         50 million           40,000
   Liver fluke Clonorchis sinensis     20-30 million        ?
   Chagas’ Disease Trypanosoma cruzi   15 million           43,000

These parasites cause untold suffering and death in the world today.
    Examples of Medical Importance in the World

The life expectancy of an Egyptian is in the mid-40's due to
15 million children in the world will die this year from a
combination of malnutrition and _________________________
Over 1 million African children will die this year from the
effects of _____________________
Many cases of _____________________, transmitted by fleas,
still occur throughout the world.
    Examples of Medical Importance in the U.S.

We in the comfort of the U.S. are not immune from parasites.
  - Many of us may have been hosts of the
  - Common parasitic diseases in the Midwest include:
    Importation of Parasites from Tropics to the U.S.

Movement of persons from all areas of the world have introduced
parasitic diseases into the U.S.
   • Numerous cases of _______________________________
   are brought back by vacationers from the tropics
   • __________________________ is often employed in areas
   endemic with many parasites
   • __________________ immigrants have brought their
   parasites with them.
             Veterinary Importance of Parasites
Many species of parasites infect our domestic animals:
   •   In Africa, cattle cannot be raised in an area equal to that of
       the U.S. due to __________________________
   •   A poultry farmer can be wiped out by
   •   Cattle, pigs, and sheep infected with parasites fail to gain
       weight and may not reproduce.
   •   Dogs may become infected with _____________________
   •   Cats are infected by many species of __________________
      Some Veterinary Parasites may infect Humans

Several dog parasites are transmissable to humans:
   • Intestinal roundworm _______________________ can
   infect humans causing the disease Visceral Larva Migrans
   • Many species of dog and cat tapeworms can infect humans
Cattle are infected with _______________________ that can
contaminate drinking water to infect humans
___________________________ occurs in many species of birds
and mammals and can cause serious congenital infections in
                Economic Importance of Parasites
Inability to raise livestock in Africa has led to ______________________

Debilitating effects of parasitic diseases on humans results in a loss of

Attempts to control parasites by treating infected persons, providing
adequate water supplies and sewage disposal, applying costly insecticides,
etc. is a major drain on _________________________________________

Thus, an understanding of parasites is important to students in biology,
the medical sciences, the veterinary sciences, and public health.
Parasites occur in two of the five kingdoms of living organisms.

What are the 5 kingdoms?
KINGDOM PROTISTA - contains the single-celled protozoans.

Kingdom contains 11 phyla where parasites are found:

EUGLENOZOA - __________________________
PHYLUM SARCODINA – __________________________
PHYLUM CILIOPHORA - __________________________
PHYLUM APICOMPLEXA - ___________________________
       KINGDOM ANIMALIA contains 32 phyla.

Parasites of importance are concentrated in 3 phyla.

PHYLUM PLATYHELMINTHES – _______________________________

PHYLUM NEMATODA - _____________________________________

PHYLUM ARTHROPODA - ___________________________________
        In addition to studying the parasite, an understanding of the
               HOST ANIMAL is important in Parasitology.

1. _________________________are often complex involving many animal hosts.
        Example: Chinese liver fluke requires 3 hosts:

        ____________________                   _____________________

2. Parasitologists must understand the _______________________________ among
animals to know how a parasite can be transmitted from host to host.
3. Parasitologists must have an good understanding the biology of host animals.

        • where in the body do you find parasites? (most parasites occur in the
        intestinal tract, but many other organs can serve as a parasite habitat)

        • how do parasites into and out of the body? (i.e. how does the adult of
        the Chinese liver fluke get to the liver; how do the eggs of the Chinese
        liver fluke get out of the human body)
______________________________ - what effects do parasites have on the
       functioning of the internal systems of their hosts?

________________________- what effects do parasites have on the tissues
      of their hosts?

_____________________________ – how is an organ’s structure and function
       altered by a parasite?

_____________________________ - how does the host's immune system respond
       to the presence of a parasite?

Thus, it is important that a student of parasitology have a good
background in the basics of biology.

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