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Flashcards in Test 1 Notes Deck (84):
1

Factors Influencing Distribution of Parasitic Disease

1. Rapid Travel
2. Immigration
3. Increased number of immunocompromised patients

2

Amebia of duck, geese and swan. Its accidental parasite of humans causing meningitis

Naeglaria Fowleri

3

Intestinal flagella without flagellum or pseudopodia that causes diarrhea in humans

Dientamoeba Fragilis

4

Infestation

Parasitic Organism or arthropod that live on surface of a host without multiplication

5

Infection

Invasion and multiplication of a pathogenic parasite in the body with accompanying reaction by the host

6

Disease

any damage of hot tissue or organs that leads to malfunction of an organ caused by a parasite

7

Protozoa

Unicellular microscopic eukaryoticorganism

8

Helminths

worms, muticellular, often visible to the naked eye

9

arthropoda

insects lice etc.
hard exoskeletons, jointed appendages

10

Most Prevalent Tropical Diseases

7 out of 8 are parasites

11

Most harmfull infective diseases afflicting humans

5 out of are parasites

12

More than 1,000,000 people are

afflicted by parasites

13

Humans play host to

dozens of parasites

14

Parasites can also infect

animals and plants

15

Vector

Any arthropod or other living organism that transports a pathogenic microorganism form an infected to a non-infected host
Usually an intermediate Host
ex. malaria

16

Final Host

the host organism in which a parasite passes its adult and or sexual reproduction phase (trophozoite)

17

Intermediate Host

The host organism in which a parasite passes its larval stage or asexual reproduction phase
Vector is usually an intermediate host

18

Mosquitos in Malaria

Anopheles mosquitos carry plasmodium and transmit malaria from host to host. The mosquito is the Final host.
Humans are intermediate hosts.

19

Reservoir Host

An animal that harbors a species of parasite and can serve as a source of parasitic infection for human
Can also be the intermediate host

20

Vector

usually an intermediate Host, an invertebrate (insect) that transmits the larval or juvenile parasite by its bite. It is a vehicle by which some parasites are transmitted from host to host

21

Premunition

Immunity, generally of a low level, resulting from the continued presence of the parasite (chronic). It does not eliminate the original infective parasite but is prevents hyper infection

22

Premunition

A poorest who has been infected is producing immunity but is not strong enough to wipe out he parasite

23

Disease

interruption of the normal function of an organ and or a morbid change in a tissue

24

Infection

acquisition of a microorganism that may establish itself (grow and reproduce) in/on a host or may be transient in a host

25

Infestation

microorganism living on the surface of a host. Pets with Flees

26

All parasites elicite immune responses including the formation of

IgM, IgG, and IgA antibodies

27

Host's immune response to parasitic infection is complex and time consuming and sometimes ineffective. Why?

1. Rapid rate of reproduction
2. Large size
3. Production of slime layer
4. Complex life-cycle (various morphological forms and antigen conversions)
5. Masking of there surface antigens withe n host cell maker (HLA= Human leukocyte Antigen)
6. By=production can prevent the function of antibodies macrophages lymphocytes and cause immunosuppression
7. Production of high level of IgE Antibody (Helminth Worm)
8.Induce T-Cell delayed hypersensitivity response (protozoa)
9. Concominant
10. Parasitic organism that had a long coevolution with their host

28

Concominant

Parasites larval form can be destroyed by host antibodies, and the presence of these antibodies provide resistance to reinfestation by new larvae

29

Protozoa

Single Celled organism, animal like, microbes usually having motility

30

Classification of Protozoa

1. style of movement
2. Mode of reproduction
3. Stages in life Cycle

31

Sarcodina

Ameba

32

Sarcodina/Ameba

Pseudopdia (false feet)
some flagella during reproduction

most are not infectious

Reprodution Binary Fission

Usual form cyst

33

Enamoeba histoytica

only human pathogen ameba

34

Mastogophora

Glagellata

35

Mastogophora/Flagellata

flagella with some ameboid species
sexual and asexual reproduction
most free living
some parasite

36

Trypanosoma and Leishmania

Flagellata parasites with one flagellum

37

Giardia

Flagellata parasite with 4 flagellum
Intestinal

38

Trichomonas

Flagellata parasite with 6 flagellum
reproductive tract

39

Ciliphora

Ciliata

40

Ciliphora/Ciliata

Moved by Cilia
also used for attachment and feeding
Transverse fission = asexual
majority free living

41

Balantidium coli

only pathogenic Ciliate
lives in animals intestines may infect humans

42

Sporozoa

Movement not characteristic
soe flagella or pseupoda preset
well developed asexual and sexual stages
most form cyst
ALL ARE PARASITIC

43

Plasmodium

causes Malaria
100-300 million cases/year in world

44

Transition of protozoa

ingestion infected stage or protozoa
arthropod vector

45

Sacodina/Ameba

General Characteristics


1. Motile and parasite to human intestine
2. Reproduce by simple asexual division
3. Most common in the lower GI tract
4. Some form of non-feeding, non-motile cyst stage
which is infective to humans
5. Transmission by ingestion of cyst in fecaffy contaminated food or water

46

Morphological Life Cycle of Amebea:


Trophozoite---Active feeding cell
This stage is metabolizing stage and sensitive to environmental change.
Cyst---A dormant form that can survive for periods outside the host.

47

Morphological Life Cycle of Amebea:

It is surrounded by mineral wall, mostly calcium, and is resistant to environmental changes ( e.g....heat, cold ...etc.).
May have 1-8 nuclei depending to species Each nucleus can produce one adult trophozoite during excyst stage
Infection usually acquired by ingestion of food or drink contaminated with cyst

48

Excystation--Amebea

Cyst survive the oral and gastric secretions but alkaline pH and digestive juice stimulate excystation within 24 hours.

49

Cyst to Trophozoites

One nucleus = one Trophozoite

50


Encystation - Amebea


As trophozoites moves along with bowel
movement, the environemnt becomes drier and the trophozoites start to undergo encystation

51

Cyst formation

cannot occur in active dysentery because the feces are so rapidly flushed from body.

52

Transmitionof Protozoa


1. Ingestion of the cyst stage in food/water and hand to mouth.
2. Via arthropod vector - such as the mosquito. Usually, these infect
subcutaneous tissues, deep organs etc.
3. Intimate contact - such as trichomonas found in the oral passage, urethra
of males, vaginal tract of females. We transmit the adult organism from person to person or host to host (sorry - the picture was cut out to avoid X-rating).
4. Penetration of the skin - usually these would be things like hookworms. The parasite is out in the environment and penetrates into the skin to the
circulatory system which takes it to the intestinal tract. Anther example is swimmer's itch.

53

Trophozoite

requires ample food and moisture to remain active.

54

Cyst stage

dormant, resting stage
when conditions in the environment become unfavorable for growth and feeding.

55

Encystment

he trophozoite cell fOlmds up into a sphere, and its ectoplasm secretes a tough, thick cuticle around the cell membrane.

56

Excystment

If provided with moisture and nutrients, a cyst break open and releases the active trophozoite.

57

Trophozoite

adult stage of protozoa. There is lots of cytoplasm surrounding the nucleus. Trophozoites are produced by binary fission (asexual). The trophozoite has mobility. In humans, they are usually found in the small intestines which is very wet and highly acidic. As it passes to the rectum the pH rises and the oxygen content decreases so that by the rectum the stool is well formed. These changes are bad for the protozoa and since there is no more moisture and nutrient it undergoes excystment to cyst stage by the rectum.

58


Cyst

dormant stage. Just a nucleus with very little cytoplasm. The cyst forms when the organism sense the pH, moisture and oxygen change and decides to condense its nucleus and squeeze out all of the free water. The only water left is bound water - water bound to the chromosomes. The DNA is double stranded and hydrogen bonding holds the strands together. That hydrogen bonding comes from water that is bound to the DNA Bound
water does not freeze nor does it become steam if you heat up that organism. As a result, the cyst can be out in the environment for long periods of time through freezing and ultra hot temperatures and survive. The cyst may contain 1-8 nuclei depending on the species. One cyst that contains 8 nuclei will give rise to four adult forms. (We said the cycle is both protective and reproductive ).

59

trophozoite vs cyst

The trophozoite usually produces the symptoms but we usually consume and excrete the cyst. cyst tends to be the infective stage

60

Host-Parasite Relationship: Depends on various factors:

I. Number of parasites: pathogenicity is usually proportional to the number of adults that are present.
2. Different people have different tolerance levels.
3. Toxic secretions - are what actually cause diarrhea to occur. 4. Host Response: Natural and acquired resistance.

61

Entamoeba Histolytica

amebic dysentery

62

Entamoeba Histolytica
Epidemiology

Worldwide

63

Entamoeba Histolytica
Forms

Trophozoites in large intestinal
mucosa, liver, or other tissues

64

Entamoeba Histolytica
Infection

Ingestion of cyst in
fecally contaminated food or water

65

Entamoeba Histolytica
Disease

Amebiasis, amebic dysentery, amebic hepatitis (if the liver is involved)

Enteritis with
abdominal pain
and bloody dysentery Diagnosis: cysts and trophozoites in feces

66

Entamoeba Histolytica
Symptoms

abdominal pain, fever" diarrhea, fatigue, bloody dysentery and weight loss.

67

Entamoeba Histolytica
extraintestinal

a. amebic hepatitis-necrotized
and fluid develop at the site of invasion of trophozoites Symptoms: Enlarged liver, fever, chills, and leukocytosis.
b. pulmonary amebiasis-by direct penetration of the diaphragm get to the lung.
c. Less frequently invade spleen, kidney, skin, and brain.

Chronic infection may last for years, and
amebiasis is often spread by chronic healthy carriers.

68

Entamoeba Histolytica
Primary infectionsite

Cecum

69

Dysentery

Dysentery is diarrhea with blood and mucous in it

70

Naegleria Fowleri-

Free living ameba---
Normally found among water fowls, ducks, geese
and swans. They are abundant in standing fresh
water, lake, ponds, and even swimming pools and hot tubs.
In animals it causes an intestinal infection with diarrhea or dysentery.
Accidental parasites of human, and may cause primary acute meningeoencephalitis.

71

trophozoite of Naegleria

small, flask- shaped that moves by a single broad pseudopod.

72

Naegleria fowleri
Disease

Primary acute meningoencephalitis
Infection begins through nasal passage as a result
of swimming or diving.
Amebic form=>
l nasal mucosa=>
2 multiplication =>
3 migration=>
4 cross the
cribiform plate=>
5 enters the brain and meninges
6 rapid destruction brain and spinal tissues
7 hemorrhage and coma
8 death within a week

73

Naegleria fowleri

(primary amebic (acute) meningoencephalit is (PAM)

74

Naegleria fowleri
Epidemoilogy

Worldwide

75

Naegleria fowleri
How Disease Occurs

Accidental entrance of free living water-borne trophozoites through nasopharynx mucosa

Water up nose forcefully

76

MASTIGOPHORANS (THE FLAGELLATES)
General characteristics:


1. Free living to parasitic
2. Inhabit the gastrointestinal tract, atria (an opening, in humans refers to the mouth, vagina, and urethra), bloodstream and tissues of human
3. Extensive role in human disease

77

Trichomonas Vaginalis:
Reservoir--

human urogenital tract

78

Trichomonas Vaginalis
Signs/Symptoms


Pathogen of the reproductive tract that causes
SID caned trichomonoiasis (Trichomonad vaginitis in females and urethritis in males).
Symptoms and sign:
female--
creamy, odorous, green to yellowish vaginal discharge, vulvitis, cervicitis and urinary
frequency and pain.
persistant vaginal inflammation causes tenderness edema, and itching
male--
asymptomatic infection- (for years that can lead to proctitis)
symptomatic infection- recurring urethritis with a milky discharge and prostate infection
majority of infected male are asymptomatic carriers

79

Trichomonas Vaginalis

trich

80

Trichomonas vaginalis
Disease Producing Form

Trophozoites in urethra or vagina

81

Trichomonas vaginalis
Infection

Sexual Contact

82

Trichomonas vaginalis
Disease

Trichomonad vaginitis, urethritis, trich

Irritating, frothy vaginal discharge in women; men usually asymptomatic Diagnosis: trophozoites in urine or vaginal smear (no cysts formed)

83

Trichomonas vaginalis

venereal disease

84

Trichomonas tenax

Is a normal organism of the human body commonly found in the oral passage. It is NOT a pathogen, but rather it is beneficial to us serving as a scavenger along the gingiva.