Microbiology Unit 3

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1

Controlling Microbial Growth

temperature (dentures proteins)
moisture
filtration
safety cabinets
osmotic pressure
radiation
chemicals

2

Resident (normal) microflora

microbes that are supposed to be present in the environment or on a surface.

3

Antiseptic

a disinfectant safe enough for use on the skin

4

Transient Microbes

microbes that are transferred from objects or surfaces to the skin

5

Disinfectant

used to clean inanimate objects

6

Purpose of disinfectants and antiseptics

to reduce the population of microbes normally through chemicals

7

Biosafety levels

the four safety levels in labs dealing with pathogens

8

Biosafety Level 1 (BSL-1)

mostly environmental microbes or normal flora
Not much of a risk to handle
non-pathogenic

9

Biosafety Level 2 (BSL-2)

can cause infection but work with such small populations it never really poses a threat
must still use good aseptic technique to minimize the amount of contamination of objects

10

Biosafety Level 3 (BSL-3)

work with massive quantities of pathogenic microbes (can be a larger quantity of BSL-2)
must work in a more clean and secure environment
may need some vaccinations prior to the lab
need to use good aseptic technique

11

Biosafety Level 4 (BSL-4)

No vaccines or treatment for microbial infections
must use barrier protection
survival rate is very small if contaminated

12

Salmonella typhi

causes typhoid fever and salmonellosis
can be associated with contaminated water or milk cultures

13

Symptoms of typhoid fever

high fever and enters a coma

14

Symptoms of Salmonellosis

aka food poisoning
nausea, vomiting, diarrhea, and fever

15

Caused the decline in Salmonella typhi deaths in the US

water chlorination
milk pasteurization
detection of diseased persons
preventative vaccination
antibiotic therapy
Sewage treatment plants improvements

16

Joseph Lister

hand washing prior to surgery (decline in infection rates)
heat sterilization of surgical instruments
application of phenol (carbolic acid) to wounds
antiseptic and disinfectants during surgery
improved survival rate

17

Autoclave

device that gets to at least 121 degrees Celsius to clean instruments within the device

18

Best conditions for heat sterilization

steamed heat under pressure

19

5% phenol is used today as...

the comparative standard for new disinfectants

20

Aseptic

"against infection"
used to minimize bacterial growth of any sort

21

Degerming

removing germs by scrubbing with aseptic soap to reduce transient and residential flora

22

Sanitize/Sanitation

cleaning up using a cleaner to reduce the population of microbes.
ex. soap and solvents

23

Pasteurization

71.2 degrees Celsius for 15 seconds

24

Sterilization

killing of or elimination all (hazardous) microbes in or on a device

25

Bacterio-

referring to bacteria

26

Fungi-

referring to fungi

27

Viri-

referring to viruses

28

-cidal

killing (chemicals are normally used)

29

-static

slowing down growth enough to allow immune system to fight off or remove

30

Factors that affect the efficacy of antimicrobial methods

relative susceptibility of microorganisms

31

3 classifications of germicides.

high, intermediate, & low

32

Germicides are classified based on?

their effectiveness

33

Germicide

a chemical used to kill germs

34

Prions

most resistant microbes
almost impossible to destroy but not easily found or transmitted

35

Most gram-negative bacteria

found in the middle of the spectrum between most resistant and least resistant

36

Bacteria and viruses

some of the easiest microbes to destroy

37

High Temp with an antimicrobial chemical

only a few minutes needed to kill majority of microbes

38

Low temp with an antimicrobial chemical

longer than the high temp, but may be necessary for certain substances that cant withstand the extreme temps

39

Effects of high temps

denaturation of proteins, nucleic acids, lipids, and carbs
interference with cytoplasmic membrane and cell wall

40

Thermal Death Point (TDP)

lowest temperature that kills all cells in broth in 10 minutes
(highly standardized)

41

Thermal Death Time (TDT)

time to sterilize volume of liquid at a set temperature
(tries to find ideal time and temp)

42

Decimal Reduction Time

reduce the number of microbes present to a small value
D-value time to require at a given temperature to kill 90% of the organisms being studied (reducing to a small number)

43

Moist Heat

denatures
destroys cytoplasmic membranes

44

More effective: dry heat or moist heat?

moist heat

45

Why is moist heat more effective than dry heat?

because the water in the moist heat is good at absorbing choleric heat energy that can then be transferred

46

Methods of microbial control using moist heat

boiling
autoclaving
pasteuization
ultra-high temp. sterilization

47

Boiling

100 degrees Celsius

48

Autoclaving

121 degrees Celsius, 15 lb/in. squared.
this is the standard it is not the only autoclaving procedure

49

Flash Pasteurization

72 (71.2) degrees Celsius for 15 seconds

50

Methods of microbial control using dry heat

oven
incinerator

51

Using an oven

170 degrees Celsius for 2 hours

52

Historical (batch) Pasteurization

56 degrees Celsius for 30 minutes

53

Effects of refrigeration and freezing

causes a decrease in microbial metabolism, growth, and reproduction (similar to hibernation)
may lead to desiccation and lyophilization

54

Desiccation

drying and removing water

55

Lyophilization

freeze drying
they freeze the microbes and remove the water through a vacuum

56

Use of filtration equipment

take a solution and use a membrane filter to siphon out microbes including viruses
helps to determine if microbes are present
the only thing allowed through is sterile liquid

57

Use of Biological Safety Hood/Cabinet

keeps the field and environment clean and helps prevent the transmission of bacteria to the person using the hood

58

Safety Glass in Safety Hood

limit entrance and exit of bacteria

59

Air flow in the safety hood

is constant and should not be obstructed

60

Class I Safety Hood can hold

BSL 1, 2, & 3

61

Class II Safety Hood can hold

BSL 1, 2, & 3

62

Class III Safety Hood can hold

BSL 4

63

Microbial Growth can be controlled by

osmotic pressure
radiation

64

Osmotic Pressure

how much water and chemical is inside and outside of the cell

65

Tonicity

changing the osmotic pressure in or out of the cell

66

Hypertonic

lots of chemical within
(salt, sugars, etc)

67

High osmotic pressure on the outside of a cell and low osmotic pressure on the inside of the cell =

water leaving the cell
desiccation

68

Low osmotic pressure pressure outside the cell and high osmotic pressure on the inside of the cell =

water enters the cell
lysis

69

Ionizing ray examples

x-rays
gamma rays

70

Ionizing rays are

the most powerful source of sterilizing

71

Nonionizing ray examples

UV rays

72

Process of nonionizing rays

it is still powerful, but item must be exposed for a longer period of time to be sterilized

73

A longer wavelength =

less powerful

74

A shorter wavelength =

more powerful

75

Purpose of UV rays

surface sterilization

76

Purpose of x-rays and gamma rays

penetrating surfaces

77

Chemicals used to control microbial growth:

phenol & phenolics
halogens
alcohol
heavy metals

78

Use of Phenol

AKA carbolic acid
was first antiseptic used in surgery
now used as the golden standard for antiseptics to be compared to

79

Examples of Halogens

Idophores (iodine and betodine)
Bleach (chlorine)
Bromine gas

80

Use of Iodophores

can be an antiseptic

81

Why is bleach not an antiseptic?

because it begins to break down every 24 hours, and must be reapplied

82

Use of bromine gas

an antiseptic but very corrosive

83

Examples of heavy metals

silver, mercury, and copper

84

Use of heavy metals

natural antiseptic

85

Phenol Coefficient (PC)

quantified killing power of a standard quality control organism
the higher the number the more effective it is

86

Examples of surface active agents

soaps (alkaline),
detergents (dissolve cell membranes)
quats (can rub the microbes away)

87

What is Triclosan?

soap

88

Hexaclorophene can not be used on...

babies

89

Example of aldehydes and acids

formaldehyde

90

What do aldehydes and acids do?

change the pH

91

Example of gaseous sterilants

chlorine

92

How is chlorine used to sterilize water?

in its gaseous state

93

Examples of oxidizing agents

peroxides and ozone

94

What do enzymes do to microbes?

they can attack and break down parts of the organism

95

Quaternary Ammonium Compounds (quats)

popular use as a disinfectant in health professions & is fairly strong but some opportunistic microbes can use this as a food source and continue to grow.

96

Opportunistic Microbe

a microbe that takes the opportunity to cause an infection (at the wrong place at the wrong time) & has adapted to use the human skin tissue as a food source

97

Example of an opportunistic microbe

Pseudomonas (microbe found in soil and water)
can be transferred by contact.

98

Pseudomonas can be found...

in some wounds (especially extensively burned patients)
in soil and water
in buckets of disinfectants

99

Virulence factor

chemicals produced by frank pathogens that cause pathological changes

100

Saphylococcus aureus

the #1 cause of a wound infection
will produce a pale white pus
is a frank pathogen

101

Frank pathogen

an obligate
if there is enough present at the right time it will cause infection

102

Pseudomonas species

produces a blue-green pus

103

Chemical effectiveness can be tested by...

(tube) dilution test & filter paper-disk diffusion

104

(Tube) dilution test

also used for antibiotic testing
looking for Minimum Inhibitory Concentration (MIC)
dilutions of select disinfectants are inoculated with a controlled amount of microbes, incubated, and looked at for the minimum amount of disinfectant needed to have no visible growth

105

Filter paper-disk diffusion

a highly standardized procedure (pH of agar, correct depth, etc..) disks are placed in the disinfectant concentrate & placed on the agar plate. for results you look at the area of the growth of the zone of inhibition (measured in mm) tests for effectiveness and susceptibility of a bacteria to a disinfectant

106

Criteria for Disinfectant Selection

fast acting
only effective against microorganisms (safe enough to use on skin and work surfaces)
deep penetrating without damage to surface
stable, easy to prepare
inexpensive & easy to use
smell pleasant

107

Kelsey-sykes capacity test

european methodology
uses a dilution procedure in timed intervals that is spread on to separate agar plates and incubated to see possible growth of microbes after incubation

bacterium + chemical => sub culture => determine viability by turbidity

108

In-use test

environmental check before and after use of disinfectants and cleaning
reality check
sample everything (where microbes hide) & then clean & then swab same areas again. Compare results
ideally everything should be gone

109

Antimicrobials are deterred through

chemotherapy

110

Paul Ehrlich

the chemist the proposed the "Magic Bullet"
1910 Salvarsan
Coined the term chemotherapy

111

Magic Bullet

the idea that somewhere on Earth there is a chemical magic bullet that can reverse any infection

112

1910 Salvarsan

a chemical used to treat infections caused by Treponema palladium
although helpful, it is made with arsenic so it is toxic
FIRST SYNTHETIC ANTIMICROBIAL

113

Treponema pallidum

causes syphilis

114

Alexander Fleming

found lysozyme and penicillin (1928) useful against bacteria

115

Lysozyme

an enzyme that breaks down peptidoglycan (the building blocks of bacterial cell walls)

116

Penicillin (1928)

mold growing on bacteria
wasn't very stable in its natural state

117

Ernest Chain

the biochemist that figured out how to create penicillin in a stable state to be used for treatment

118

Howard Florey

the physician who was the first to use penicillin as a form of treatment

119

Gerhard Domagk

1932- synthesized Prontosil and sulfa drugs that could be sprinkled on battlefield wounds to prevent infections

120

Selman A. Waksman

1940-1948
a soil microbiologist who used extracts from the soil and fungi to produce actinomycin, streptomycin, & neomycin.

121

Streptomycin

first antimicrobial to treat tuberculosis

122

Neomycin

used in skin ointment

123

Beta Lactam Ring

the working part of penicillin that interferes with peptidoglycan formation in bacteria

124

Antibiotic

antibacterial made by fungi to kill or inhibit bacteria

125

Penicillium notatum

first historic species to produce penicillin

126

Penicillium chrysogenum

used in modern manufacturing of penicillin
(produced penicillin in a greater quantity than P. notatum)

127

Semisynthetics

chemically altered antibiotics that are more effective than naturally occurring ones

128

Synthetics

antimicrobials that are completely synthesized in a lab

129

Examples of Synthetics

Salvarsan & sulpha drugs

130

Needed for an Ideal antimicrobial agent

readily available
inexpensive
chemically stable
easily administered
nontoxic & nonallergenic
selectively toxic against a wide range of pathogens

131

Antimicrobials, antibacterials, antifungals, & antiprotozoans all must have :

selective toxicity
a spectrum of activity
mode of action
minimal side effects
minimal drug resistance from microorganisms

132

Selective toxicity

targeting the bug not the patient
drug kills the microorganism not the host

133

Therapeutic dosage level must be

very distant from toxic dosage level

134

Broad spectrum

both gram positive and gram negative bacteria are targeted

135

Narrow spectrum

a select few species ( or all species in one genus) are targeted

136

Modes of action

inhibition of cell wall synthesis (BEST ONE!)
disruption of membrane function
inhibition of protein synthesis
inhibition of nucleic acid synthesis

137

Penicillin V

penicillin derivative that is acid resistant

138

Methicillin

penicillin derivative that is penicillinase resistant

139

Dicloxacillin

penicillin derivative that is acid & penicillinase resistant

140

Examples of Inhibition of metabolic pathways

quinolones interfere with malaria parasites (deadliest parasite)
heavy metals inactivate enzymes (ex. silver, mercury, lead) problem: very toxic
antiparasitics disrupt tubulin polymerization & glucose uptake in parasitic protozoa & worms (destroys motility structure and starves parasite)

141

Antimetabolites

competitive inhibitors (sulfa drugs & trimethoprim)
look like enzymes such as Para-aminobenzic acid
bacteriostatic

142

Bacteriostatic

slow organism growth so the microorganism can be flushed out by the body or scrubbed away.

143

Antiviral

slow down the viruses so the immune system can take over.
medicines target viruses metabolisms, but the best way is to prevent viral entry into a cell.

144

Problem with treating viruses

viruses grow inside our cells so it is hard to target them with an antiviral

145

Alieve

could interfere with influenza

146

Antifungal

not a huge arsenal because of the similarities to our cell structures.
difficult to get past additional barrier that fungi have (fungal cell wall)
medicines target cell wall synthesis, plasma membrane synthesis, and nucleic acid formation

147

Routes of Administration

topical
oral
intramuscular
intravenous

148

Benefits and down falls to oral administration

takes a few days to reach therapeutic level, but can be easily administered at home

149

benefits and down falls to intramuscular administration

hits microbes with a high therapeutic level quickly, but must be given in a health care facility

150

benefits and down falls to intravenous administration

very high therapeutic level that is maintained consistently, but it must be given and monitored in a health care facility

151

Side effects of antimicrobial drugs

Drugs may be toxic to kidneys, liver, or nerves
It may or may not be safe during pregnancy
possible allergic reactions including anaphylactic shock

152

Anaphylactic shock

severe allergic reaction that is life threatening because the air ways begin to close

153

If disruption of normal microbiota (normal flora) occurs during the use of antimicrobial agents...

secondary infections and superinfections can occur

154

Disruption of normal microbiota (normal flora) means

an antimicrobial agent is so powerful that is has killed the microbe and has also significantly decreased the normal flora allowing space for new microbes to invade without protection

155

Amphotericin B

attaches to ergosterol in fungal membranes

puts a pore in the cytoplasmic membrane so the cells loses all of its content

156

Downfall to Amphotericin B

humans could be susceptible because cholesterol is so similar to ergosterol the bacteria may attack the human cells

bacteria lack sterols so they are not susceptible to this drug

157

Aminoglycosides - Gentamicin

block the inhibition of translation & cause the misreading of mRNA

158

Tetracyclines

block the attachment of tRNA to the ribosome

159

Macrolides

prevent continuation of protein synthesis

160

Chloramphenicol

prevents peptide bonds from being formed

161

Candida albicans

causes candidiasis, thrush, & vaginitis

162

Clostridium difficile

causes pseudomembranous colitis (inflammation of the colin at the surface of the membrane. causes constant diarrhea)

163

Lateral gene transfer

acquisition of R-plasmids by transformation, transduction, or conjugation

164

Antimicrobials have much less effect due to...

new mutations of the chromosomal genes

165

B-lactam drugs - penicillin & cephalosporin

interfere with the formation of peptide side chains between adjacent strands of peptidoglycan by inhibiting penicilling-binding proteins (peptide chains are broken)
alters the cell wall stability

166

Bacitracin

interferes with the transport of peptidoglycan precursors across the cytoplasmic membrane (the building blocks)
alters plasma membrane and cell wall

167

Inhibit cell wall synthesis

penicillins, cephalosporins, vancomycin, bacitracin, isoniazid, & ethambutol

168

Inhibit protein synthesis

aminoglycosides, tetracyclines, chloramphenicol, & macrolides

169

Cross Resistance & multiple resistance

pathogens can acquire resistance to more than one drug by transferring the resistance to different genre of organisms

170

R-plasmids being exchanged

the genes in the extra chromosomal fragments are transferred

171

Constant use of drugs has..

eliminated sensitive cells causing superbugs, cross resistance, and resistance to antimicrobial drugs

172

Cross resistance

resistant to more than one drug or resistant to all the drugs in the same family

173

Resistant S. aureus

first well-known resistant bacteria

174

Preventing resistance

maintain a high concentration of drug in patient for sufficient time
(kills all sensitive cells and inhibits others so the immune system can destroy)
Use antimicrobial agents in combination (two is better than one)

175

Synergism

combining drugs to assemble a greater affect than just hitting with one drug

176

Antagonism

drugs that work against one another (want to avoid)

177

Retarding the Resistance

use antimicrobials when necessary
develop new variations of existing drugs
search for new drugs
use bacteriocins

178

Bacteriocins

bacteria made substance used to kill other bacteria

179

Antibiotic Susceptibility/Sensitivity Testing (AST) includes

Minimum inhibitory concentration (MIC)
Minimum bactericidal concentration (MBC)
ETest

180

Kirby-Bauer Test

filter paper disc is placed on a bacterial lawn.
interpretative chart must be used to look at the zone of inhibition
Problem: technically difficult & only interprets outcome of what serum drug level is needed (doesn't tell for any other specific body fluids)

181

Minimum inhibitory concentration (MIC)

tubes lined up from most concentrated to least concentrated & exact number of bacterial cells is added to each tube
looking for the minimum concentration to have no turbidity seen in the tube (good for all body fluids)

182

Minimum bactericidal concentration (MBC)

one step farther than MIC
looking for bacteria in the clear tube
Subculture with no growth confirms the MIC
No growth must occur on the agar plate

183

ETest

a piece of membrane filter with varying concentrations of the drug are present
MIC value would be where the growth stops on the agar plate
helps to determine drug & dosage needed

184

Serum cidal level

reserved for patients who are not responding to an antibacterial
they take samples of the patients serum and infuse the agar plate with the pathogen to see what is going on

185

Vitek

company that manufactures things for micro lab that need to be very small; so small a light can be shown through them to record info

186

Domain Eukarya

common unicellular & multicellular
macroscopic & range in functionality including pathogenic
divided into classes by motility

187

Motility by pseudopodia

Ameboid cells such as Entamoeba histolytica and Naegleria fowleri
move by "false feet" that stretch out their plasma membrane and stick it on to a surface and pull itself that way

188

Entamoeba histolytica

can affect the digestion tract (mainly intestines) & cause diarrhea, colitis, & dysentary in amoebic form
thru oral-fecal transmission
can easily migrate to the liver or peritoneal cavity (triggers inflammation response)

189

Amoeba form is...

a trophozoite

190

Trophozoite

soft shell made of just the cytoplasmic membrane & you can see pseudopodia
susceptible to drugs in this form

191

Cyst

encapsulated form that has a very sturdy structure, is very spherical, and is the most difficult to treat

192

Naegleria fowleri

thermophile that is the primary cause of amoebic meningitis
found in warm, untreated stagnant water
migrates to the CNS via the oral cavity
100% mortality rate

193

Trichomonas vaginalis

primary cause of protozoan vaginitis
can also cause prolonged postpartum fever, endometritis, premature rupture of membranes, & cytological changes in the cervical cell morphology

194

Signs of Trichomonas vaginalis

no cyst forms
no mitochondria
most curable STD
lemon shaped with 2 pairs of flagella

195

How to ID Trichomonas vaginalitis

using a "hanging drop" wet mount - a drop of liquid with the organism is placed on a cover slip & suspended to be viewed (can also use a wet mount and get the same results)

196

Anaerobic flagellates

cells that move by flagella

197

Giardia lamblia

moves by flagella
tear drop shape with 2 nuclei
no mitochondria
AKA backpacker's diarrhea, or bever fever

198

Giardia duodenalis

trophozoite and cyst forms
trophs are tear drop in shape
they look like they are starring back

199

Cure for parasites

gin & tonic
cocktail introduced by the army of the British East Indian Company in India

200

Why does gin & tonic work?

the tonic water contains the chemical quinine, which helps prevent malaria

201

Eukaryotes that have no motility structures

Plasmodium vivax
P. falciparum
P. malaria
P. ovale
P. knowlesi

202

Plasmodium vivax

most common cause of malaria

203

Plasmodium falciparum

most lethal carrier of malaria
urine is black or brown
AKA "black water fever" or "malignant tertian malaria"

204

P. malaria
P. ovale
P. knowlesi

rare malaria in occurrence

205

Plasmodium knowlesi

newest malaria in humans (used to only be found in animals)

206

endemic diseases

more common in a specific geographic location & has ideal conditions for a particular disease

207

Malignant tertian malaria

symptoms occur every 2-3 days along with fever and chills

208

Plasmodium

causes malaria
egyptians described symptoms in 3000 BC
is an intracellular parasite
a biological vector (insect facilitates transfer of disease)

209

Biological vector of malaria

anopheles mosquito (female)
they are the most likely to carry malaria

210

Malaria

has a ring feature (not much cytoplasm)
will eat the innards of the red blood cell
its life cycle goes from the red blood cells to the liver.

211

Toxoplasma gondii

definitive host: intestines of cats
Intermediate hosts: mammals and birds (accidentally transmitted & does not stay in intestines, it migrates)
extraintestinal (humans- brain, heart, skeletal muscle)
oral-fecal or organ transplant & transplacental transmission
forms cysts that can be ingested and cause infection

212

Toxoplasma gondii causes

leading cause of spontaneous abortion due to protozoan parasite (pregnant women should avoid cleaning cat litter boxes)
could be infected for the rest of your life

213

Infective stage of Toxoplasma gondii

fecal oocyst in fecal & muscle of animals we eat, food, & water

214

Diagnostic stage of Toxoplasma gondii

transplanted tissue, in our muscles and organs, & abortion

215

Things that cause fetal neurological damage

"T"- Toxoplasma (protozoan)
"O"- others
"R"- Rubella
"C"- Cytomegalovirus
"H"- Herpesvirus

216

Viruses that cause fetal neurological damage

rubella
cytomegalovirus
herpesvirus

217

Complex of teratogens

chemicals that target developing fetal tissue & damage it

218

How to avoid Toxoplasma gondii

handwashing & throughly cooking meat

219

Trypanosoma cruzi

protozoan pathogen
causes chagas disease (aka american trypanosomiasis)
endemic throughout much of mexico, central america, and south america

220

endemic disease

a disease that is located in a specific geographical region

221

Trypanosoma cruzi

caused by triatomine bug (aka kissing bug)
causes an acute and a chronic disease
20-30% of infected people will develop debilitating or life-threatening conditions in the heart, liver, and spleen
display Romana's sign

222

Romana's sign

inflammatory response and swelling from the kissing bug

223

Aschelminth

rounded bodied worms that are long, thin, and tube shaped

224

platyhelminthes

flat, segmented bodied worms
ex. tape worm

225

Avoid Nematoda by

WASHING YOUR HANDS!

226

Ascaris lumbricoides

roundworm
largest, most common parasite found in humans (1,000,000,000 people infected)
causes ascaris pneumonia
can burrow through tissue (dragging along bacteria from intestines)
dioecious
MIGERATES

227

Infective stage of Ascaris lumbricoides

eggs, larvae, fertilized eggs

228

Diagnostic stage of Ascaris lumbricoides

finding the worm, deposit fertilized & unfertilized eggs, & larva]

229

Ascaris lumbricoides females are...

larger than the males
a result of the female carrying all of the eggs

230

dioecious

two separate sexes

231

Ascaris pneumonia

larvae migration causing hemorrhage and edema in lungs

232

Intestinal blockage

caused by ascaris lumbricoides blocking the intestinal tract (large mass of communities of worms)
notorious for migration

233

Sensitive to anesthetics

ascaris lumbricoides
patients in surgical recovery rooms have had worms migrate from the small intestine through the stomach and out of a patients nose, mouth, or even tracheotomy tubes

234

Enterobius vermicularis

pinworm
infects about 400,000,000 people world wide
"D" shaped infective eggs

235

Infective & Diagnostic stage for Enterobius vermicularis

eggs of perianal folds, larvae inside & eggs

236

Lifecycle of Enterobius vermicularis

entire life cycle is in the human host
female lays eggs at night around the perianal region causing an inflammatory response and the urge to itch

237

To collect a sample of Enterobius vermicularis

use Graham sticky tape method (aka "scotch tape" method)
repeat 3-5 times
the fertilized eggs are sticky and easily transferred

238

Avoiding Necator americanus

dont go barefoot in the woods!

239

Necator americanus

aka north american hook worm or creeping nematodes
has infective larvae
burrows through host skin, passes from blood stream, to lung to digestive tract where they live in the intestine of the host
adapted to go back and forth from lungs to digestive tract
latch onto intestines

240

Avoiding Trichinella spiralis

cook meat hot!

241

Trichinella spiralis

causes trichinosis
infective encysted larvae in the meat from a pig
need a biopsy to confirm trichinosis

242

life cycle of trichinella spiralis

reproduce in the small intestine
eggs hatch (stomach uncovers cyst form)
larvae migrate especially to skeletal muscle

243

eosinophils

white blood cells that respond to allergies & parasites
normal level- 0%-5%
25%-70% increase in level due to a parasite

244

Examples of platyhelminthes

tapeworms
cestoda
parasitic

245

Parts of a playhelminth

scolex
proglottids
hermaphroditic

246

Tapeworms

longest worm - up to 30 feet

247

scolex

head of tapeworm
has a circle of hooks & suction cups to latch on

248

proglottids

segments in the worm (relatively loose connection that will tear easily)

249

hermaphroditic

both sex organs are present in each segment

250

Taenia saginata

beef tapeworm

251

Taenia solium

pork tapeworm

252

Ways to contract Taenia

eating undercooked meat or touching undercooked meat and not properly washing your hands

253

Taenia solium is...

worse than taenia saginata

254

Best specimen to see Taenia

to see segments in the stool

255

infective stage of Taenia

larvae in cow and pig muscle
oncosphere in cysticerci

256

diagnostic stage of Taenia

fertilized eggs and segments

257

Cysticerci

infective larvae in the muscle of an animal

258

life cycle of taenia

infective cysticercus in raw or undercooked pork or beef muscle
adults tend to stay in the intestines, but other areas of the body including the leg can also be infected with cysticerci

259

cysticercosis

infection with cysticerci

260

neurocysticercosis

larval tape worm in the brain causing headaches, migraines, passing out, and seizures
treated with drugs or removal of the worms through surgery

261

neglected parasitic infections

receive relatively little attention through devotion to their surveillance, prevention, and/or treatment

262

Neglected parasites include

Chagas disease - trypanosoma cruzi
Cysticercosis - taenia solium
Toxocariasis - toxocara canis (less commonly toxocara cati)
Toxoplasmosis - toxoplasma gondii
Trichomoniasis - trachomonas vaginalis

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Chagas disease

caused by trypanosoma cruzi

264

Cysticercosis

caused by taenia solium
leading cause of epilepsy among hispanics in the US

265

Toxocariasis

caused by toxocara canis (less commonly toxocara cati)

266

Toxoplasmosis

caused by toxoplasma gondii

267

Trichomoniasis

caused by trachomonas vaginalis

268

CDC works to...

protect people from health threats from things such as neglected parasites

269

People can be protected by...

increasing awareness among physicians and the public
synthesizing the existing data to help better understand these infections
improve diagnostic testing
advising treatment, including distributing otherwise unavailable drugs for certain infections (Chagas disease)

270

Dog round worm

Toxocariasis cani
phylum: nematoda
zoonotic disease
located worldwide
definitive host: dogs
Intermediate host: none
accidental host: humans and other mammals
children are more susceptible than adults

271

Zoonoses

a disease passed from animals to humans (especially from mammals)

272

Toxocarasis cati

the feline form of toxocarasis

273

Infection of Toxocarasis cani is transferred by/ found in ...

intestines (ingested eggs)
Transplacenta
transmammary

274

T. cannis infects...

puppies born with infection
puppies less than 5 weeks
humans (in the heart, liver, lung, brain, muscle, or eye)

275

Infective stage of T. cannis

eggs and larva

276

Diagnostic stage of T. cannis

eggs, larva, & tracks on skin

277

two types of larvae migration

ocular larvae migration (OLM)
visceral larvae migration (VLM)

278

Ocular larvae migration (OLM)

caused by larva migration to the retina

279

Visceral larvae migration (VLM)

caused by the movement of worm larvae throughout various organs of the body

280

Controlling creeping nematodes

treat dogs, especially puppies, regularly for worms
good hygiene practices when handling animals
don't let children play in areas dogs are allowed to defecate
teach children not to eat dirt or soil