M
MICROBIOLOGY & PARASITOLOGY
C3
PREFINALS PARASITOLOGY
Parasites are organisms that usually depend on - Migratory birds serve as the reservoir host for
the host for survival and are classified in the parasite Capillaria philippinensis which
several ways people normally get from contaminated fresh
Based on habitat water.
Ectoparasites
- parasites that live outside the host's body (e.g., Paratenic hosts
fleas, lice). - are those that serve as a means of transport
- Invasion of the body by ectoparasites is called for the parasite (e.g., insect vectors) so that the
infestation. infective stage of a certain parasite may reach
Endoparasites its final host
- Lives inside of the body by endoparasites is
called infection and is the result of entry and SORCES OF EXPOSURE TO INFECTION OR
multiplication of the parasite within the host. INFESTATION
Based on ability to live independently of - Exposure to parasites may occur through one
the host or more of the following sources
Facultative parasites o contaminated soil or water;
- parasites that can live independently of the o food containing the parasite's infective
host (i.e., free living). stage
- do not have to live inside a host to complete o a blood- sucking insect
their life cycle. o a domestic or wild animal harboring the
Obligate parasites parasite
- parasites that must live inside a host (e.g., o another person his or her clothing,
Plasmodium Leishmania, hookworms). bedding, or the immediate environment
- Majority of the parasites that infect humans are he or she has contaminated
obligate parasites o one's self (auto-infection)
Based on mode of living Soil contaminated/polluted human feces
Permanent parasites - The most common source of exposure to
- parasites that remain in a host from early life to infection
maturity (e.g., Plasmodium) - This is true for most of the parasitic worms or
Intermittent parasites helminths such as Ascaris lumbricoides,
- parasites that simply visit the host during Trichuris trichiura, Strongyloides stercoralis,
feeding time (e.g., non-pathogenic parasites and human hookworms
Incidental parasites Water
- parasites that occur in an unusual host (e.g., - Water may be the source of the viable cysts of
dog tapeworm in humans) the parasitic amoebae and intestinal
Transitory parasites flagellates, the larvae of the blood flukes, and
- parasites whose larva develops in a host while the eggs of the pork tapeworm Taenia solium.
the adult is free-living (e.g., Echinococcus - Freshwater fish serve as the source for the fish
granulosus or dog tapeworm) tapeworm Diphyllobothrium latum, as well as
Erratic parasites other intestinal and liver flukes.
- parasites that are seen in an unusual organ, - Raw pork is the source of Trichinella spiralis
different from that which it ordinarily and Taenia solium, while improperly cooked or
parasitizes (e.g., Ascaris lumbricoides in the raw beef is the source of Taenia saginata.
lungs or kidneys Blood-Sucking insects
- May serve as source for certain parasites
HOSTS - Female mosquito for the malaria parasite
- essential to the existence of parasites Plasmodium; sand fly for leishmaniasis;
- organisms that harbor the parasite and provide - tsetse fly and reduviid bug for trypanosomes;
nourishment to the parasite and the Culex and Mansonia mosquitoes for
Types of Hosts filariasis.
Definitive Host Dogs
- are hosts that harbor the adult stage of the - Dogsare the direct source of infection with the
parasite (e.g., humans for the intestinal round hydatid cyst of the dog tapeworm Echinococcus
worm Ascaris), granulosus.
- where the sexual stage or sexual phase of the - Other animals that may serve as sources for
life cycle of the parasite occurs (e.g., mosquito parasites include pigs, cows, and birds
for the malaria parasite Plasmodium Human
Intermediate hosts - are directly responsible for a considerable
- are those that harbor the larval stage of the amount of infection with the pathogenic
parasite (e.g., cow for the cysticercus larva of amoeba Entamoeba histolytica, the pinworm
the beef tapeworm Taenia saginata), Enterobius vermicularis, and the dwarf
- where the asexual stage of the life cycle of the tapeworm Hymenolepis nana.
parasite occurs (e.g., humans for the malaria - Auto-infection accounts for some of the
parasite Plasmodium). infections and some re-infections with
Reservoir hosts Hymenolepis nana, Enterobius vermicularis,
- Are vertebrate hosts that harbor the parasite and Strongyloides stercoralis.
and may act as additional source of infection in
man.
Hannah Adan 1
MICROBIOLOGY & PARASITOLOGY
C3
PREFINALS PARASITOLOGY
Parasites are organisms that usually depend on - Migratory birds serve as the reservoir host for
the host for survival and are classified in the parasite Capillaria philippinensis which
several ways people normally get from contaminated fresh
Based on habitat water.
Ectoparasites
- parasites that live outside the host's body (e.g., Paratenic hosts
fleas, lice). - are those that serve as a means of transport
- Invasion of the body by ectoparasites is called for the parasite (e.g., insect vectors) so that the
infestation. infective stage of a certain parasite may reach
Endoparasites its final host
- Lives inside of the body by endoparasites is
called infection and is the result of entry and SORCES OF EXPOSURE TO INFECTION OR
multiplication of the parasite within the host. INFESTATION
Based on ability to live independently of - Exposure to parasites may occur through one
the host or more of the following sources
Facultative parasites o contaminated soil or water;
- parasites that can live independently of the o food containing the parasite's infective
host (i.e., free living). stage
- do not have to live inside a host to complete o a blood- sucking insect
their life cycle. o a domestic or wild animal harboring the
Obligate parasites parasite
- parasites that must live inside a host (e.g., o another person his or her clothing,
Plasmodium Leishmania, hookworms). bedding, or the immediate environment
- Majority of the parasites that infect humans are he or she has contaminated
obligate parasites o one's self (auto-infection)
Based on mode of living Soil contaminated/polluted human feces
Permanent parasites - The most common source of exposure to
- parasites that remain in a host from early life to infection
maturity (e.g., Plasmodium) - This is true for most of the parasitic worms or
Intermittent parasites helminths such as Ascaris lumbricoides,
- parasites that simply visit the host during Trichuris trichiura, Strongyloides stercoralis,
feeding time (e.g., non-pathogenic parasites and human hookworms
Incidental parasites Water
- parasites that occur in an unusual host (e.g., - Water may be the source of the viable cysts of
dog tapeworm in humans) the parasitic amoebae and intestinal
Transitory parasites flagellates, the larvae of the blood flukes, and
- parasites whose larva develops in a host while the eggs of the pork tapeworm Taenia solium.
the adult is free-living (e.g., Echinococcus - Freshwater fish serve as the source for the fish
granulosus or dog tapeworm) tapeworm Diphyllobothrium latum, as well as
Erratic parasites other intestinal and liver flukes.
- parasites that are seen in an unusual organ, - Raw pork is the source of Trichinella spiralis
different from that which it ordinarily and Taenia solium, while improperly cooked or
parasitizes (e.g., Ascaris lumbricoides in the raw beef is the source of Taenia saginata.
lungs or kidneys Blood-Sucking insects
- May serve as source for certain parasites
HOSTS - Female mosquito for the malaria parasite
- essential to the existence of parasites Plasmodium; sand fly for leishmaniasis;
- organisms that harbor the parasite and provide - tsetse fly and reduviid bug for trypanosomes;
nourishment to the parasite and the Culex and Mansonia mosquitoes for
Types of Hosts filariasis.
Definitive Host Dogs
- are hosts that harbor the adult stage of the - Dogsare the direct source of infection with the
parasite (e.g., humans for the intestinal round hydatid cyst of the dog tapeworm Echinococcus
worm Ascaris), granulosus.
- where the sexual stage or sexual phase of the - Other animals that may serve as sources for
life cycle of the parasite occurs (e.g., mosquito parasites include pigs, cows, and birds
for the malaria parasite Plasmodium Human
Intermediate hosts - are directly responsible for a considerable
- are those that harbor the larval stage of the amount of infection with the pathogenic
parasite (e.g., cow for the cysticercus larva of amoeba Entamoeba histolytica, the pinworm
the beef tapeworm Taenia saginata), Enterobius vermicularis, and the dwarf
- where the asexual stage of the life cycle of the tapeworm Hymenolepis nana.
parasite occurs (e.g., humans for the malaria - Auto-infection accounts for some of the
parasite Plasmodium). infections and some re-infections with
Reservoir hosts Hymenolepis nana, Enterobius vermicularis,
- Are vertebrate hosts that harbor the parasite and Strongyloides stercoralis.
and may act as additional source of infection in
man.
Hannah Adan 1
