Micro PAR 8 Flashcards
1
Q
Parasites are (eukaryotic/prokaryotic) organisms
A
EUKARYOTIC
- lack a rigid cell wall
2
Q
There are over ____________ single celled parasites and more than ____________ helminths
A
10,000 single celled parasites
more than 50,000 helminths
3
Q
How can parasites reproduce?
A
Sexual and asexual modes
4
Q
Main habitat of parasites?
A
Fresh water, but some are found in soil
5
Q
Endoparasites
A
parasites that live inside the host (ex. Ascaris lumbricoides)
6
Q
What are the 2 categories of parasites?
A
protozoa and helminths
7
Q
How many cells make up protozoa and helminths?
A
protozoa– UNICELLULAR
helminths– MULTICELLULAR
8
Q
What are the 4 divisions of protozoa?
A
Amebae
Flagellates
Sporozoa
Ciliates
** classified by how they move around and life cycle
9
Q
What are the 3 divisions of helminths?
A
nematodes (roundworms)
cestodes (tapeworms)
trematodes (flukes)
** think about these classifications as shapes
10
Q
Amebae examples? (genus)
A
Entamoeba
Naegleria
11
Q
Flagellate examples? (genus)
A
Giardia
Trichomonas
12
Q
Sporozoa examples? (genus)
A
Plasmodium
Babesia
Toxoplasma
13
Q
Ciliates example? (genus)
A
Balantidium
14
Q
Nematodes examples (genus)
A
Ascaris
Ancylostoma
15
Q
Cestodes examples (genus)
A
Taenia
Echinococcus
16
Q
Trematodes examples (genus)
A
Fasciola
Schistosoma
17
Q
How do ameba and sporozoa move?
A
ameba– move by psuedopods
sporozoa– lack a locomotive organelle
18
Q
Protozoa size?
A
2 to more than 100 mm
19
Q
Helminths size?
A
less than 1mm to more than a meter long
20
Q
Routes of parasitic infections?
A
- contact and penetration of eyes
- contact and penetration of skin
- vector- borne
- inhalation
- fecal-oral/ingestion
- sexual contact
21
Q
Trophozoite
A
feeding and reproducing stage that lives WITHIN the host
undergo encystment before leaving the host (usually in feces)
22
Q
Cyst
A
INFECTIVE form that survives in the ENVIRONMENT
undergo excystment when ingested, developing into trophozoites
23
Q
Infection of E. histolytica may spread to the….
A
liver, lungs, or brain
24
Q
Does E. histolytic have an intermediate host?
A
NO.. mature cysts enter by ingestion, and then trophozoites leave in the feces
25
E. histolytica symptoms (acute v. chronic)
Acute: frequent **dysentery with necrotic mucosa and abdominal pain**
Chronic: recurrent episodes of **dysentery with blood and mucus in the feces**. Cysts are found in the stool. The organism may invade the **liver, lungs, and brain and result in liver dysfunction, pneumonitis, and encephalitis**.
26
Trichomonas vaginalis
flagellate
causes genital and urinary infections
has undulating membrane
DOES NOT HAVE CYST STAGE
transmitted sexually
most common pathogenic protozoan of humans in industrialized countries
27
Does trichomonas vaginalis have a cyst stage?
NO
28
Giardia lamblia
worldwide distribution-- **most frequent protozoan intestinal disease in the US and most common water-borne disease**
inadequate water purification or drinking contaminated water
infection by **INGESTION of CYSTS**
- decystation in the duodenum
- trophozoites colonize upper small intestine.. can attach to sub-mucosal epithelium via a SUCTION DISK
- free trophozoites encyst on the way to the colon-- passed in the stool
DIAGNOSIS: finding **cysts in fecal smears**
man is primary host
reservoirs: beavers, **pigs**, monkeys
29
2 main diseases caused by hemoflagellates?
Leishmaniasis
Trypanosomiasis (African and American forms)
30
Leishmaniasis
**L. donovani** causes visceral leishmaniasis (Kala-azar, black disease)
transmitted by **blood-feeding sand flies** (phlebotomus)
flagellated parasites multiply and move to proboscis
in human-- **infect mononuclear phagocytes** until the infected cell ruptures
reservoirs: dogs and rodents
31
Trypanosoma cruzi
American trypanosomiasis (Chagas' disease)
rural areas of central and South America
may cause sudden death from stroke or heart attack
32
Trypanosoma brucei
African sleeping sickness
transmitted by tsetse flies (live in central africa)
33
Sporozoa-- definition and major diseases?
- lacking cilia, flagella, or pseudopods
- single nucleus
- apical complex (this is how it moves)
- sexual and asexual generations
- life cycle includes _DIFFERENT SPECIES_
Major diseases: **toxoplasmosis, malaria**
34
Toxoplasma gondii
causes **TOXOPLASMOSIS**
worldwide distribution
infection is a very serious threat in immunocompromised and pregnant women
T. gondii mostly found in **cats (feces) and farm animals**
- contact w infected cat feces
- consumption of raw or undercooked meat that is infected
Infection is **TRANSMITTED DURING PREGNANCY** (through placental connection)
**DAMAGE TO THE EYE**-- usually invades the retina and choroid tissue. Visual acuity can be affected
35
Malaria
caused by **PLASMODIUM** SPECIES (there are 4)
world's **most prevalent vector-borne disease**
symptomatology of malaria depends on:
- the parasitemia
- presence of the organism in different organs
- parasite burden
incubation period-- between 10-30 days
headache, lassitude, vague pains in the bones and joints, chilly sensations, fever
**requires TWO HOSTS: a mosquito and a vertebrate**
parasite undergoes **development in liver cells prior to infecting red blood cells**. In RBCs, the parasite **DIGESTS HEMOGLOBIN** and leaves behind indigestible portions and waste materials in the blood cell-- blood cell ruptures, waste release may be associated with some of the symptoms
36
What are the 4 plasmodium species that can cause malaria?
P. falciparum
P. vivax
P. ovale
P. malariae
37
Malaria diagnosis
mainly based on:
- **presence of fever**
- patient history-- always suspect malaria in feverish travelers from an endemic area
blood smears-- **RING SHAPED TROPHOZOITES**
antibody tests or PCR
38
Helminthic Parasites
macroscopic, **multicellular, eukaryotic worms**
complex life cycles
**intermediate host often needed to support larval stages**
3 groups-- cestodes (tapeworm), nematodes (roundworm), and trematodes (flukes)
39
Cestodes
flat, segmented intestinal parasites
NO DIGESTIVE SYSTEM (because it is a tapeworm)
all tapeworms have the same general body plan
40
All tapeworms LACK a _______________ system.
Digestive
41
Taenia
Cestode (tapeworm)
**cattle and swine are intermediate hosts**-- humans living close to livestock have a greater risk
parasite attaches to intestinal epithelium causing intestinal blockage
**Taenia saginata-- BEEF tapeworm** (6-12 feet)
**Taenia solium-- PORK tapeworm** (12-26 feet)
**SCOLEXES** of T. solium and T. saginata-- attachment/suction cup to intestinal wall
42
Trematodes
aka **FLUKES-- flat, leaf-shaped worms**
rudimentary digestive track
attach to host via ventral sucker to obtain nutrients
intermediate host: **MOLLUSCS** (freshwater snails or land snails)
either **penetrate skin or are ingested by eating raw fish**
Clinically significant trematode: **Schistosoma** species
initially, mild symptoms like rash or itch, infection may persist for years and damage organs such as liver or bladder
43
Intestinal vs. Tissue Roundworms (nematodes)
INTESTINAL NEMATODES (roundworms):
- Ascaris (Giant intestinal roundworm)
- enterobius (pinworm)
- Necator/ancylostoma (hookworm)
TISSUE NEMATODES (roundworms):
- Trichinella spiralis (Trichinosis)
44
Life Cycle features of Roundworms
parasites of almost all vertebrates
have a number of reproduction strategies
**intestinal nematodes-- shed their eggs into the lumen of the intestine
- eggs are eliminated in feces
- eggs are consumed in contaminated food or water**
**other nematodes encyst in muscle tissue and are consumed in raw or undercooked meat (trichinella spiralis)**
- can sometimes see these in ham
45
Trichinella spiralis
Trichinosis is related to the quality of **pork** and consumption of poorly cooked meat
direct lifecycle, meaning it **completes all development stages in ONE HOST**
**larvae encyst in muscle**
46
How many bacterial species are in the oral microbiome
more than 700
47
What are the 9 distinct communities of the oral microbiome
_K SSS TTT PB_
keratinized gingiva
sub-gingival plaque
supra-gingival plaque
saliva
tongue
tonsils
throat
palate
buccal mucosa
48
In dental plaque, a complex micro environment is organized around which bacteria?
Corynebacteria (filamentous)
49
How do corynebacteria form calculus?
attach firmly and grow slowly
precipitate calcium from saliva--> calculus formation
50
How are individual taxa localized in biofilm?
By their functional niche
51
Where does streptococcus grow in the biofilm?
Strep grows near the tips of the biofilm
uses oxygen, which creates anoxia near the core
52
What bacterial metabolism can lower blood pressure?
nitrate metabolism
53
What bacterial substance can help prevent obesity?
Butyrate-- made by oral and gut microbiomes
54
"The periodontal disease communities are organized around integrated pathways for the metabolism of..."
- butyrate
- tetrahydrofolate
- histidine degradation
- nucleotide biosynthesis
55
AHL
N-acyl homoserine lactone (quorum sensing signal)
released by the biofilm in response to cells and soluble factors from the host (like what neutrophils release when they degranulate)
56
Neutrophil actions on biofilm?
degranulate, phagocytose bacteria, release extracellular chromatin
57
______% of American Adults have periodontitis
**47.2%**
most is moderate periodontitis, but there is also mild and severe periodontitis present throughout the population
58
Normal/Healthy Oral Microbiome
survive daily physical and chemical perturbations from food intake and personal hygiene-- able to form a long-term stable microbiome
help prevent dysbiosis
59
Tolerance Induction Hypothesis
1. pregnancy causes spontaneous bleeding of the gums (pregnancy gingivitis)
2. bacteria get into the blood stream and are transferred to the placenta
3. oral bacteria of mother get trapped in the placental tissue
4. Fetal APCs "scope out" alloantigen information and take it back to the fetal peripheral lymphoid organs
5. fetal regulatory T cells (Treg) that recognize the mothers microbiome as "safe" are generated in the fetal lymphoid tissue
**EVIDENCE**
- microbes are present in placenta, umbilical cord blood, and amniotic fluid in full-term pregnancies without overt infection
- placental microbiome does not resemble vaginal or gut microbiomes-- it is most similar to the normal oral microbe
60
Far-Reaching Consequences of Periodontal disease
Systemic inflammation (TNF, IL-1b, IL-6)
- causes liver to release CRP, fibrinogen, and serum amyloid A
Systemic bacterial dissemination
- promotes atherosclerosis (can be predisposing factor for heart disease
Swallowing bacteria
- lead to dysbiosis in the gut --> endotoxaemia--> systemic inflammation contribution
Inflammation-induced pregnancy complications can happen when all of the above problems are stacked
61
Periodontal disease and atherosclerosis
PD occurs in a large number of heart disease patients
potential reason: pro inflammatory systemic response
oral microbes can be identified in the blood and atherosclerotic plaque in blood vessels
62
Citrullination
unusual AAs not present in normal transcription are introduced... caused by **exogenous** things like tobacco
has a role in **arthritis (cyclic citrullinated peptide, CCP)**
reaction is also called _deimination_
- arginine residue is converted to a citrulline residue by **PAD4** in the presence of water.. rxn releases ammonia
Hypercitrullination can be associated with **autoimmunity in rheumatoid arthritis**-- autoantibodies against citrullinated proteins are created (causes neutrophils to migrate and an immune complex forms)
**Patients with periodontal disease have MORE CITRULLINATED PROTEINS**
