Midterm 2 Flashcards
1
Q
What are the five major branches of eukaryotic microorganisms?
A
Fungi: yeasts, molds, or fleshy fungi
Algae: photosynthetic
Protozoans: single celled eukaryotes with animal characteristics
Slime molds: can be single celles or multicellular mold
Helminths: parasitic worms
2
Q
Describe fungi
A
Appear as yeast, molds, fleshy fungi
Few fungi are pathogenic (<1%)
Generally grow as filamentous, multicellular organisms
Form filaments called hyphae or unicellular organisms
Have cell wall composed of strong flexible polysaccharides called chitin
3
Q
What is mycelium?
A
A collective mass of hyphae
4
Q
Describe yeast
A
Single cells that reproduce by budding
Some may become multicellular by connecting budding cells
May require oxygen or grow in absence of oxygen
5
Q
What is saccharomyces cerevisiae?
A
A model budding yeast
6
Q
Describe molds
A
Rapidly growing
In an appropriate environment, hyphae grow to form a myeclium
Generally, hyphae have cross walls called septa
Some have coenocytic hyphae (no septa)
7
Q
What is the purpose of septa?
A
Divide the hyphae into distinct uninuclear, cell-like units called septate hyphae
8
Q
What are the classifications of fungi?
A
Basidiomycota: mushrooms and fruiting bodies
Lichens: consists of hyphae of a fungus and Cyanobacteria or green algae, symbiotic
Zygomycota: multinucleate molds
Ascomycota: primary fungi causing food spoilage (penicillium)
9
Q
Describe ascomycota
A
Sac fungi, includes molds with septatehyphae and some yeasts
Asexual spores usually produced in long chains from the conidiophore
Detach from chain at slight disturbance and float in air like dust
10
Q
When does an ascospore form?
A
Forms when the nuclei of two cells that can be either morphologically similar or dissimilar fuse
Spores are produced in saclike structure called ascus
11
Q
Describe the life cycle of fungi
A
All fungi have some form of asexual reproduction
Most can also reproduce sexually which introduces variation
Often occurs during changing environment
Filamentous fungi reproduce by fragmentation of their hyphae and by spore formation
Yeast bud
12
Q
Describe asexual reproduction by fungus
A
Sporangia release spores into the environment
Spores can cause infection after inhalation
Sporangiospores form in sporangium and spores release when ruptured
Conidiospores are produces at tip or sides of hyphae, no sac, pinch off at tip of a fertile hyphae - or segmentation of a preexisting végétative hyphae
13
Q
Describe sexual reproduction of fungi
A
Introduces genetic variation
Occurs when nutrients are limited or other unfavourable conditions are present
Mating types are designated as + and -
Fungal spores are compact and lightweight
Can be dispersed widely throughout the environment by air, water, other organisms
14
Q
Name some women with historical influence on STEM
A
Mary anning: paléontologist in 1800s who found and described many species and introduced extinction but got no credit
Mary Tharp: earth scientist in 1940s who discovered sea floor spreading but dismissed as Girl talk
Rosalind franklin
15
Q
What is the most common type of infection?
A
Respiratory infection
16
Q
Why is the respiratory system prone to infection?
A
Circulate a lot of air and huge surface area in lungs
In many parts, only a single celles layer separates the external environment from internal
Over 200 types of viruses that can cause common cold alone
17
Q
What are the three main parts of the respiratory system?
A
Airway, lungs, and respiratory muscles More specifically: - external nose - nasal cavity - pharynx, larynx, and trachea - bronchi/bronchioles - lungs - diaphragm and respiratory muscles
18
Q
What are alveoli?
A
Thin/hallow cavities that are the site of gas exchange in the lungs
19
Q
What criteria must be met for an infection to be caused an exogenous agent?
A
- Sufficient number (dose) of infectious agents (airborne or contained in droplet) must be inhaled
- Must remain alive and viable in air
- Organism must find susceptible tissue for attachment/growth
- Once in respiratory tract, must colonize in surface before it can cause disease
20
Q
What are the most common bacteria found in the normal flora of the upper respiratory tract?
A
Staphylococcus aureus and S. Epidermidis
21
Q
What is the défense mechanism of the lungs?
A
Mucous in lungs
Cilia beat upwards clearing mucous and produce new mucous
22
Q
What are fomites?
A
Anything that could harbour infectious agents
23
Q
How does the respiratory tract get infected?
A
Damage to the mucosal lining allows bacteria in normal flora to become infectious
Damaged by smoking, dryness, she pollution, laryngitis, allergies
Often viral infections cause damage allowing bacterial species in for secondary
24
Q
What are most respiratory infections?
A
90% of acute and 50% of lower respiratory infections are primarily caused by viruses
25
Describe the common cold
```
Viral infection of the upper respiratory tract that primarily effects the nose and nasal cavity
Most frequent human disease
Rhinoviruses are the leading cause
3-5 days
Highly contagious and opportunistic
No specific treatment
```
26
Describe the influenza virus
An infectious viral disease caused by influenza virus
Caused by orthomyxoviruses - group V meg ssRNA viruses
Person to person or by fomites
Cause complications; secondary infections, worsening of chronic conditions such as asthma or congestive heart failure
27
What are the three genera of influenza?
Influenza A: infects humans, other mammals, birds, and causes all fly pandemics
- cause most severe disease state
Influenza B: infects humans and seals
Influenza C: humans, pigs and dogs
28
What are the symptoms of influenza?
Fever, headache, fatigue, dry cough, sore throat, rhinitis, myalgia
Gastro-intestinal symptoms (sometimes) - more common in children then adults
29
Describe the progression of influenza
5-6 days after contact, symptoms appear
Contagious about a day before symptoms to a week after
Initial symptoms are fever, headache, aches, muscle pains, fatigue
Moves into upper respiratory tract and develop sore threat then stuffy nose, sneezing, and dry cough (around 3 days)
30
Describe viral pneumonia
Pneumonia: severe inflammation of the lungs, specifically alveoli
About half caused by viruses
Causes fevers, nonproductive cough, rhinitis, myalgia, headache
Most cases are mild, severe forms. Ah require hospitalization and be treated with antivirale and humidified air
31
Describe hantavirus pulmonary syndrome (HPS)
Deadly disease caused by hantaviruses
Carried by rodents - transmission through contact with infected animals, their waste
Begins with childlike symptoms, and progress to acute respiratory stress syndrome
Fatalities in 30 to 40% of cases
32
Describe SARS
Zoonotic
In 2006, genetic link between human SARS and féline SARS found
Person to person transmission via drop
Can be life threatening, especially in vulnerable populations
High fever, headache, body aches, dry cough, followed by pneumonia
Treatment includes antipyretics, supplemental oxygen, additional ventilator support
33
Describe the 2002 SARS outbreak
Seems to have originated in mainland China
Spread worldwide for several months before curtailed by help from WHO
Reported to have mortality rate of 9.5%
Symptoms appear 2-10 days but mostly with 2-3 days and 10-20% need ventilation
34
Describe streptococcal pharyngitis (strep throat)
Caused by group A streptococcus - specifically streptococcus pyogènes
Most common bacterial infection of the throat
Most common in children
Affects back of throat, uvula and tonsils
White or red spots, inflammation
35
Describe scarlet fever
Group A beta-hemolytic streptococci; S.psyogens
Begins with fever and sore throat, night also exhibit chills, vomiting, abdominal pain
Strawberry tongue due to erythrogenic exotoxin that damage capillaries under the skin - causing the red rash
36
Describe streptococcus pneumonia
Gram positive, encapsulated alpha-hemolytic diplococcus
Can be found in resident flora
Common cause of mild respiratory illness
Main cause of community acquired pneumonia and meningitis in children and the elderly
37
How do you treat pneumococcal pneumonia?
Since 2007, resistant strains have become common
Mechanism of resistance to penicillin and cephalosporins is through alteration of cell wall targets, penicillin-binding proteins (PBPs)
Can be overcome if the antibiotic concentration at the site of infection exceeds the MIC of the organism for 40-50% of the dosing interval
38
Describe mycoplasma pneumoniae
Small bacteria that lacks a cell wall
Hospitalizes 6509 people per year in Canada
Primary atypical/uncomplicated pneumonia - relatively mild
Usually affects people younger than 40
Usually due to crowded areas
39
Describe chlamydophima pneumonia
One of the major causes of pneumonia or bronchitis
Transmission by respiratory secretions
Most common in school age children
Community acquired pneumonia - easily passed from one individual to another
40
Describe pertussis
Highly contagious
Caused by Bordetella pertussis - small, aerobic, gras-negative coccobacillus
Slow incubation, begins with cold-like symptoms and leads to severe coughing spells 10-12 days, can last 4-6 weeks, can lead to vomiting
Can cause permanent disability or death
Person to person via droplets
Vaccine available but not widespread
41
Describe TB
Caused by mycobacterium tuberculosis
Airborne
Infected persons may not show symptoms but may have latent tb
Fever, night sweats, loss of appetite
Some may go into remission or become chronic and debilitating
Transmission prevented by vaccine and antibiotics
42
Describe histoplasmosis
Contracted from soil, manure, farms caved
43
Describe coccodiodomycosis
Found in southern US to South America
| Désert soil, rodent burrows, archaeological remains, mines
44
Describe blastomycosis
1. Flu-like, often resolved in 2-3 days
2. Acute symptoms similar to bacterial pneumonia, including high fever, chills, a productive cough (brown, bloody), chest pain
3. Chronic - resembling tuberculosis or lung cancer, symptoms include low fever, productive cough, night sweats, and weight loss
4. An aggressive and sever disease that causes ARDS, a life threatening condition that causes lung swelling and fluid buildup in the air sacs
45
Describe aspergillosis
Generally mild, may lead to secondary pulmonary arpergillosis
46
What are the different parts to the gastrointestinal tract?
Oral cavity
Stomach
Small intestine
Large intestine/colon
47
Describe the stomach
Extremely acidic, kills most bacteria that travel through it, some can survive/pass through
H. Pylori is a primary cause of peptic ulcers and gastritis - more bacteria - greater change of survival
48
Describe the small intestines flora
Duodenum difficult to colonize because of peristalsis, bile, pancreatic juice
Acid is neutralized
Primary aerobic/facultative anaerobic, gram positive bacteria
Use polysacchide walls or teichoic acid to bind mucosa
Enterococcus faecalis and lactobacilli dominate
49
Describe large intestine/colon flora
Slow flow, dense bacterial concentration, primarily anaerobic and gram negative
Use attachment pilli to bind mucosa
Bacteroides and bifobacteria dominate ilocecal valve, transverse colon, and descending colon
E. coli parent in lower amounts
50
What are the protective benefits of the resident flora?
Presence in small intestine prevents pathogens from dominating - competition, and inhibition by endo/exotoxins
Normal bacteria stimulate the growth of the intestinal lining
51
What are the structural benefits of the resident flora?
Makes up part of the intestinal barrier (mucosal)
| Critical in the natural development of the immune system
52
What are the metabolic benefits of the resident flora?
Metabolizes carcinogens in dietary foods
Provide the host with synthesized vitamins, such as biotin and folate - synthesize vitamin K
Important for the muscular activity of the small intestine
Help metabolize complex sugars
53
Describe helicobacter pylori
Spiral, microaerophillic, lophotrichous, gram negative, present in 50% if people, asymptomatic in 80-90% of cases
Neutralizes acid in its environment, buries in mycose
Present in 80-90% of ulcers
Major contributor to gastritis
54
What is a peptic ulcer and what can contribute to them?
Open sores in the mucosa of the stomach or duodenum that don't heal, acid and inflammation can perpetuate ulcers
Formation associated with cancer, physical damage, overuse of drugs, stress, and excessive alcohol use
55
Describe salmonellosis
Gastroenteritis caused by salmonella gram +
Eating infected animal related food
Can cause typhoid and paratyphoid
Incubation time and severity depends on number of organisms injested and species
Diarrhea, fever, abdominal cramps 12-72 hours
Subsides in 5-7 days
56
Describe typhoid fever
Salmonella enterica, serotype typhi
Sever intestinal disruption and red spots on chest and abdomen, elsewhere is systemic
Through contaminated food or water or direct contact
Sudden onset of slow fever, severe headaches, nausea, abdominal pain, constipation, diarrhea
Antibiotic resistance is a frequent problem
57
Describe paratyphoid fever
Enteric fever similar to typhoid but milder
Rash is common
Caused by S, enterica serotype: paratyphi
Animal to human/human to human
58
What are the differences between diarrhea and dysentery?
Diarrhea: watery stool with no blood/mucous
- disease that effects small bowel
- target only intestinal luman and upper epithelial cells
- no cell death in diarrhea, symptoms caused by release of toxins
- does not need antibiotics
Dysentery: mucoid stool that may have blood
- a disease that effect the colon
- upper epithelial cells are targeted but colon ulceration also results
- upper epithelial cells are destroyed
- almost always require antibiotics
59
Describe shigellosis
```
Bacillary dysentery and marlow syndrome
Caused by shigella
Low effective dose
Diarrhea, fever, stomach cramps
Transmitted via fecal oral route
```
60
Describe campylobacteriosis
Caused by campylobacter spp
C. jejuni is leading cause of bacterial diarrhea in US
Transmitted by handling raw poultry, eating uncooked poultry, water, raw milk, handling feces
61
Describe escherichia spp gastroenteritis
E. Coli part of normal flora but some pathogenic strains
Pathogenic strains have specialized fimbraie for adhering to microvilli
Produce
K12 - model (nonpathogenic)
DH5alpha (workhorse)
62
Describe botulism
Rare - result of bacterial produced neurotoxin
Consumption of clostridium botulinum toxin
Food borne
Weak, dizzy, blurry vision, abdominal pain
Death primarily by respiratory paralysis
63
Describe staphylococcal intoxication
Staphylococcus aureus, gastroenteritis
Staphylococcal B (SEB)
Contaminated food
64
Describe cholera
Vibrio cholerae
Can be mild or without symptoms
Profuse diarrhea, vomiting, and muscle cramps (legs)
Water supply contaminated with human feces
Rice water diarrhea
65
Describe rotavirus
Most common cause of infectious diarrhea in infants and children
Immunity develops following
8 species A-H, A most common
Fécal oral route - causes gastroenteritis
Several vaccines developed
2 day incubation, sick 3-8 days with fever and abdominal pain
66
Describe noroviruses
Cause diarrhea, nausea, muscle aches, headache, fatigue, low grade fever
67
What are some examples of gastrointestinal parasitic infections (protozoans)?
Giardiasis
Beaver fever
Amoebiasis
Cryotisporidiosis
68
Describe beaver fever
Flagellated protozoan
Live in intestinal tracts of humans and animals
Common water borne gastrointestinal disease
69
Describe amoebiasis
```
Anaerobic parasitic protozoan
Fatigue
Present in 10% of people
Primarily in underdeveloped countries
Water contaminated with human feces
```
70
Describe cryptosporidiosis
Apicomplexia protozoan
Fecal oral route
One of the most common waterborne disease in the US
71
Describe protozoans
Unicellular eukaryotes found in a wide range of habitats
Most are not harmful
Some are parasitic and capable of causing debilitating and deadly diseases
72
How do protozoan enter the human body?
Enter the human body as trophozoite, the active feeding and reproductive stage, or as a cyst, the dormant stage, become active under the appropriate environmental conditions
73
Describe the lifecycle of cryptisporidium
1. Mature oocyte ingested
2. Sporozites attach to surface of intestinal epithelium and mature
3. Sexual forms develop and produce fertilized oocysts
4. Mature oocysts in feces
74
What are some types of helminths (parasitic worms)?
```
Trichinosis
Tæniasi flatworm
Pinworm infections
Ascariasis
Necatoriasis
```
75
Describe trichinosis
Trichinella spiralis
Roundworm
Acquired by consumption of uncooked, contaminated meat
76
Describe taeniasi
Flatworm
Infect striated muscle and form cysts
Taenia saginata (beef)
Taenia solium (pigs) - larvae in contaminated meat
77
Describe pinworm infections
Enterobius vernicularis
Lives in rectum of humans
Most common worn infection in United States
78
Describe ascariasis
Ascaris lumbricoides
Most common nematode infection of humans
Common in tropical and subtropical areas
Most people are asymptomatic but may cause slow weight gain and growth
79
Describe necatoriasis
Hookworm
Bloodsucking roundworm
Necatoriasis americansus
Two species cause infection in humans
Once adult hookworm reaches intestine, attaches itself to the villi of the intestinal wall and sucks blood from its host
Can cause pain and sometimes secondary infection
80
Describe the mininges
Outer most membrane is the dura matter
The middle layer is the arachnoid
The inner most membrane is the pia mater
81
Describe the blood brain barrier
Only allows some specific molecules to enter the cerebrospinal fluid
Prevents most microorganisms from ever infecting the brain/central nervous system
82
What is meningitis?
Inflammation of the meninges in response to infection/disease
83
Define encaphalitis and méningoencephalitis
Encephalitis: inflammation of the Brian
Meningoencephalitis: inflammation of brain and meninges
84
Define aseptic meningitis
A viral infection of the CFS/méninges causes an increase in lymphocytes and monocytes as well as a slight increase in protein level
CFS remains clear
85
Define septic meningitis
A bacteria infection of the CSF/méninges cause a sharp increase in granulocytes and proteins which causes the CSF to become visibly turbid
86
What are the initial and following symptoms of bacterial meningitis?
I: nausea, vomiting, fever, headache, stiff neck
F: confusion, sleepiness, light sensitivity, possible progression to convulsion and coma
87
Why is bacterial meningitis more severe?
More sever due to production of bacterial toxins
| Early diagnosis and treatment is essential to prevent permenent neurological damage
88
Describe meningococcal meningitis
Caused by neisseria meningitides
Gram negative, aerobic diplococcus, polyssachride capsule
20% of population are asymptomatic carriers
Person to person in respiratory droplets
Sudden onset after 1-3 days
Antibiotic therapy reduces mortality rate by 9-12%
89
What are the symptoms of meningococcal meningitis?
Sore throat, headache, drowsiness, fever, stiff neck, and photosensitivity
90
Describe harmophilus influenzae meningitis (Hib)-viral?
Aerobic gram-negative coccobacillus common on throat
Causes 10-15% of bacterial meningitis in adults
Vaccine available
Direct contact with droplets of carrier or patient
Intravenous antibiotics as soon as seen
91
Describe pneumococcal meningitis
Caused by streptococcus pneumoniae
Gram positive, encapsulated, facultative anaerobic diplococcus
Carried in throat of many healthy individuals
92
Describe conjunctivitis
Pinkeye
Haemophilud influenzae is major cause as are S. aureus, chlamydia sp., N. gonnorhea, S. Pyrogens
Associated with unsanitary contact lenses
Fast onset
Some vaccines affective against
93
Describe neonatal gonorrhoeal ophthalmia
Neisseria gonorrhoeae
Transmitted to a newborn's eyes during passage through the birth canal
Prevented by treatment with antibiotics
94
How did Dr. Peter palese contribute to the study of flu season?
Recognized that guinea pigs could be infected with influenza
Showed that influenza is more infectious at cool dry temperature
Took a cage with infected guinea pigs on one side and noninfected on other
Blow current from infected to none
Found that transmission was high at lower humidity
95
What are some arguments for why the flu is more common in the winter?
The cold lowers your immune functioning
We are all inside all the time
Low humidity and low temperature increase viral lifespan
96
Describe CF
Caused a mutation in the gene cystic fibrosis transmembrane conductance regulator (CFTR)
Cause thick, sticky mucus to build up in the lungs
Can also have trouble swallowing or in digestive tract
Everything gets trapped in mucous and build up biogilms in lungs
97
Why are infections caused by pseudomonas seruginosa hard to fight?
Constantly developing a new resistance to the antibiotics
98
What is cancer?
A collection of diseases resulting from the uncontrolled proliferation of the body's own cells
99
What are some problems with cancer cells?
May invade neighbouring tissues/organs
Can siphon blood supply via angiogenesis
Steal nutrients/stress systems
Metastasize
100
What are the traditional cancer treatments?
Remove malignant masses
Administer targeted radiotherapy to kill cancerous cells
Chemotherapy: the use of chemical agents to target cancer cells by inhibiting mitosis or blocking growth signal
Encouraging a healthy body
101
What are some new age approaches to curing cancer?
Improve the specificity of drug delivery
Localize using markers
Use nanotechnology
Employ oncolytic viruses
102
Describe oncolytic viruses
Primarily infect and ultimately kill cancer cells
Generally genetically modified versions of known viruses
Prefer lysis
Oncolytic viral particles can infect adjacent cells after lysis
Stimulate the immune response to synergistically attack oncolytic cells
103
How do oncolytic viruses work?
Preferentially infect cancerous cells and label them for an immune response or lysing cells
104
How can we tell which cells are infected with oncolytic viruses?
Incorporating reporter genes allows one to monitor where the oncolytic virus is proliferating
Genetic markers will survive multiple generations
105
What do we genetically manipulate oncolytic viruses?
1. Inhibit angiogenesis: incorporate overexpressed genes that inhibit the formation of new blood vessels
2. Include sodium-iodide symptôme geners to the viral genome
3. Act as vector by incorporating suicide genes
106
What are suicide genes?
Encode enzymes that can métabolisé a seperately administered non-toxic pro-drug into a potent cytotoxin, which can diffusé to and kill neighbouring cells
107
What do NIS genes do?
Causes infected Timor cells to expresse NIS and accumulate iodine
When combined with radioiodine therapy it allows local radiotherapy of the tumour
108
Define bioterrorism
The intentional release of microorganisms or viruses to cause physical harm
109
Describe category A bioterrorism
Highest priority. Previously engineered. Easily spread and results in high mortality rate
Rabbit fever, anthrax, smallpox, bubonic plague
110
Describe category B bioterrorism
Moderately easy to spread, lower mortality rates
| Food safety threats, shigella, staphylococcus aureus, water supply threats
111
Describe category c bioterrorism
Emerging pathogens
May be engineered for mass destruction because of their availability, ease of production and dissemination, high mortality rate, or ability to cause a major health impact
H1N1, Zika, Ebola
112
Describe the use of smallpox as bioterrorism
French army used small pox to infect indigenous people
Caused by variola major and variola minor
Continued to be studied as bioterrorism agent in the 1979s
Mortality rate of 40%
Herd immunity
113
Describe how anthrax was used for bioterrorism
Disease with rapid onset caused by bacillus anthracis
Most forms are lethal
Infected meat or spores in air
Effective vaccines and treatment available
Used in 1916 by Scandinavian freedoms fighters in Finland
Cultured as bioterrorism agent by Japan in 1930s
Used in Japan in 1993 with multiple scares in US in 2001
