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BIO 286 - Microbiology > Exam "4": Microbial Symbiosis with Humans, Epidemiology, Person-to-Person Diseases, Vector-Borne Diseases, Food- and Water-Borne Diseases, and Eukaryotic Pathogens (Bio 286- Microbiology) > Flashcards

Exam "4": Microbial Symbiosis with Humans, Epidemiology, Person-to-Person Diseases, Vector-Borne Diseases, Food- and Water-Borne Diseases, and Eukaryotic Pathogens (Bio 286- Microbiology) Flashcards

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1
Q

microbiome

A

functional collection of different microbes in a particular system

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2
Q

microbiota

A

all microbes in a microhabitat

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3
Q

host microbiome supraorganism

A

a body and all of its associated microbiota

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4
Q

relationship between humans and their microbiota

A

commensalistic

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5
Q

overview of human microbiome

A

approximately 4x10^13 MICROBES IN A HUMAN MICROBIOME and only about 3x10^13 HUMAN CELLS

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6
Q

most of the human microbiota is located in the

A

colon

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7
Q

gastrointestinal microbiota

A

humans are monogastric and omnivorous… colonization of gut begins at birth… consists of stomach, small intestine, and large intestine… comprises 400 m^2 of surface area… responsible for digestion of food, absorption of nutrients, and production of nutrients by indigenous microbial flora… contains 10^13 to 10^14 microbial cells

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8
Q

stomach and small intestine

A

microbial populations in different areas of GI tract are influenced by diet and physical conditions in area… acidity of stomach and duodenum of small intestine (~pH 2) prevent many organisms from colonizing GI tract, but there is a rich microbiome in healthy stomach… FIRMICUTES, BACTERIODETES, and Actinobacteria are common in gastric fluid, while Firmicutes and PROTEOBACTERIA are common in mucus layer in stomach… HELICOBACTER PYLORI was discovered in 1980s and has since been found in ~50% of world’s population– when present, it is found in gastric mucosa

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9
Q

common bacterial phyla of gut

A

FIRMICUTES, BACTERIODES, and PROTEOBACTERIA

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10
Q

Helicobacter pylori are found in the

A

STOMACH

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11
Q

large intestine

A

intestinal microorganisms carry out a variety of essential metabolic reactions that produce various compounds… colon is essentially an in vitro fermentation vessel, with the microbiota using nutrients derived from digestion of food… most organisms are restricted to lumen of large intestine, while others are in mucosal layers

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12
Q

gut enterotypes

A

each type is functionally and phylogenetically distinct… three types: 1. enriched in Bacteriodes… 2. enriched in Prevotella… 3. enriched in Ruminococcus

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13
Q

gastrointestinal microbiota roles

A

products of intestinal microbiota and “educating” the immune system… many microbial metabolites or transformation products that can be generated in gut have significant influence on host physiology (vitamin production, modification of steroids, or amino acid biosynthesis)

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14
Q

human gut microbiome functions

A

production of essential amino acids and vitamins… maturation of gastrointestinal tract… production of volatile fatty acids from polysaccharides

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15
Q

increased methane production in gut leads to

A

elevated volatile fatty acid production

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16
Q

oral cavity

A

is a complex/heterogeneous microbial habitat… saliva contains antimicrobial enzymes… high concentrations of nutrients near surfaces in mouth promote localized microbial growth… tooth consists of a mineral matrix (enamel) surrounding living tissue, the dentin, and pulp

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17
Q

airways

A

microbes thrive in upper respiratory tract (sinuses, nasopharynx, oropharynx, oral cavity, larynx)… bacteria continually enter respiratory tract from air during breathing– most are trapped in mucus of nasal and oral passages and expelled with nasal secretions or swallowed and then killed in stomach… the lower respiratory tract (trachea, bronchi, lungs) has no normal microbiota in healthy adults– ciliated mucosal cells move particles up and out of lungs

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18
Q

microorganism most associated with dental cavities

A

streptococci

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19
Q

urogenital tracts and their microbes

A

altered conditions can cause potential pathogens in urethra (such as Escherichia coli and Proteus mirabilis) to multiply and cause disease– E.coli and P.mirabilis frequently cause urinary tract infections in women…. fungal overgrowth (candida albicans) possible… the vagina is weakly acidic and contains significant amounts of glycogen… Lactobacillus acidophilus (resident organism of vagina) ferments the glycogen to produce lactic acid (lactic acid maintains a local acidic environment)…. vaginitis commonly results from overgrowth of Candida and Trichomonas vaginalis

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20
Q

most numerous bacteria on skin

A

actinobacteria

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21
Q

skin and its microbes

A

there are approximately 1 million resident bacteria per square centimeter of skin for a total of 10^10 skin microorganisms covering average adult… skin surface varies greatly in chemical composition and moisture content… three microenvironments: dry, moist, and sebaceous… composition is influenced by: environmental factors and host factors… each microenvironment shows an unique microbiota

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22
Q

human microbiome study groups

A

have formed most of our understanding of the functions of human microbiome… human microbiome project (HMP) surveyed hundred of medical students over several years to determine a baseline for healthy human microbiomes…later projects showed the weakness in this model, as they revealed more diversity in non-US born subjects and lacked data on diet or other lifestyle attributes

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23
Q

animal models

A

while there are significant differences between mice and humans, mice have been used to good effect to study human gut microbiome interactions… mice have a larger colon and cecum than humans… most fermentation is completed in the mouse cecum rather than the human large intestine… mice models: have a short life cycle and well-defined genetic lines, can be raised in a germ-free environment, can have antibiotic therapy, strict dietary control, fecal transplants

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24
Q

colonization and succession

A

COLONIZATION BEGINS AT BIRTH WITH TRANSFER FROM MOTHER TO INFANT– early colonizing microbes are a source of vitamins and tend to be facultative rather than obligate anaerobes… variables determine the nature of the gut microbiome– vaginally born infants have a microbiome more similar to that of their mothers than those born via c-section (infants born via C-section have less Bacteriodes than vagina babies); breastfed infants have more commensal bacteria as breast milk has oligosaccharides that promote their colonization

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25
Q

when does colonization begin?

A

at birth

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26
Q

following antibiotic therapy, patients are often administered

A

probiotics to facilitate recolonization of normal microbiota in intestines

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27
Q

stability of adult microbiome and transitions with age

A

early experiences determine gut microbiome… aging and frailty are associated with decreased microbial diversity

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28
Q

inflammatory bowel disease (IBD)

A

chronic inflammation of gut and disruption of homeostasis (dysbiosis)… antibiotic use increases the risk of development… once developed, it may be transmissible between family members… individuals with this have lower gut microbiome diversity

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29
Q

role of gut microbiota in obesity: mouse models

A

Normal mice have 40 percent more fat than germ-free mice with the same diet. When germ-free mice were given normal mouse microbiota, they started gaining weight… Mice that are genetically obese have different microbiota than normal mice. Obese mice have more Firmicutes… mice grown in absence of microbes then are inoculated with healthy cecal material from other mice have genes associated with glucose uptake, lipid absorption, and lipid transport activated so the mice gains body fat without increasing energy intake

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30
Q

dental cavities and periodontitis

A

cells form a biofilm called dental plaque, which as Streptococcus and other fermenting bacteria… these fermenters produce acid, which wears down the tooth enamel… periodontal disease is thought to contribute to several systemic conditions, including cardiovascular disease and arthritis

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31
Q

antibiotics and human microbiome

A

Oral antibiotics decrease ALL microbes in the human gut (both target and non-target)… Use of antibiotics during the first few months of life increases the risk of developing IBD and other disorders related to dysbiosis…Clostridium difficile infections tend to occur following antibiotic treatment– C.difficile is a spore former and generally antibiotic resistant; the newer therapy for C.difficle infection is a fecal transplant

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32
Q

probiotics

A

live organisms that confer a health benefit to the host

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33
Q

Bifidobacterium and Lactobacillus

A

commonly used probiotics found in yogurt and probiotic drinks.. they may work by taking up space or nutrients, limiting the ability of pathogens to colonize the gut

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34
Q

prebiotics

A

typically carbohydrates that are indigestible by human hosts, but provide nutrition for fermentative gut bacteria

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35
Q

epidemiology

A

study of occurrence, distribution, and determinants of health and disease in a population

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36
Q

public health

A

health of a population as a whole

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37
Q

surveillance

A

the observation, recognition, and reporting of diseases as they occur

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38
Q

incidence

A

number of new cases of the disease in a given period of time

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39
Q

prevalence

A

total number of new and existing cases in a population in a given time

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40
Q

epidemic

A

disease that occurs in a large number of people in a population at the same time; is localized/geographically defined

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41
Q

pandemic

A

disease that occurs widespread, usually worldwide; passes geographical borders

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42
Q

endemic

A

disease that is constantly present in a population but usually at low incidences; constant, low level presence

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43
Q

sporadic

A

disease that occurs randomly, no pattern to incidence of disease

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44
Q

occurrence of Lyme Disease in Michigan is an

A

endemic

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45
Q

outbreak

A

occurs when a number of cases of a disease are reported in a short period of time

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46
Q

stage of disease

A
  1. infection… 2. incubation period… 3. acute period… 4. decline period… 5. convalescent period
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47
Q

infection

A

organism invades and colonizes the host… microbes are within host

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48
Q

incubation period

A

time between infection and onset of symptoms

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49
Q

acute period

A

disease is at its height

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50
Q

decline period

A

disease symptoms are subsiding

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51
Q

convalescent period

A

patient regains strength and returns to normal

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52
Q

chronic infections

A

host and pathogen survive

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53
Q

acute infections

A

pathogen can be selective force

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54
Q

mortality

A

incidence of death in a population

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55
Q

morbidity

A

disease refers to incidence of disease, including fatal and nonfatal diseases

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56
Q

disability-adjusted life year (DALY)

A

quantitatively measures disease burdens in terms of lost years due to disease, disability due to disease, and premature death

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57
Q

coevolution

A

Process by which two species evolve in response to changes in each other– of a host and a pathogen: the virulence of the pathogen in host-to-host transmission decreases while the resistance of host increases… but if a pathogen does not rely on host-to-host transmission then it will remain extremely virulent… saves “best of fit” diseases– decreased toxicity but increased communicability

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58
Q

herd immunity

A

resistance of a group to infection due to immunity of a high proportion of group… if a high proportion of individuals are immune to an infection then whole population will be protected… immunized people protect nonimmunized people because the pathogen cannot be passed on so the cycle of infectivity is broken… 1-1/Ro = __% of people needed to be immunized to be successful

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59
Q

common stages in mechanisms of transmission

A

escape from host, travel, and entry into new host

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60
Q

direct host to host transmission

A

infected individual transmits a disease directly to a susceptible host without assistance of an intermediary (ex: flu, common cold, STDs, ringworm)

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61
Q

indirect host to host transmission

A

occurs when transmission is facilitated by a living (vector) or nonliving (fomite) agent

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62
Q

vector

A

living agents of transmission

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63
Q

fomite

A

nonliving agents of transmission; inanimate object that can transmit disease

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64
Q

mechanical vector

A

arthropod that carries infection but is not itself infected

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65
Q

biological vector

A

arthropod that carries infection and is itself infected

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66
Q

reservoir

A

sites in which infectious agents remain viable and from which individuals can become infected

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67
Q

zoonosis

A

any disease that primarily infects animals but is occasionally transmitted to humans

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68
Q

common source epidemic

A

usually arises from contamination of water or food… endemic indicated by a sharp rise in number of cases reported daily over a brief interval (ex: cholera)

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69
Q

John Snow

A

one of the first epidemiologists, studied epidemiology of cholera

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70
Q

host to host epidemic

A

disease shows a slow, progressive rise and a gradual decline (ex: influenza, chicken pox)

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71
Q

carriers

A

pathogen infected individuals showing no signs of clinical disease… potential sources of infections… can be identified using diagnostic techniques, including culture and immunoassays… 1/4 of all people (ex: typhoid mary)

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72
Q

basic reproduction number (Ro)

A

number of expected secondary cases of a given disease from each single case… mathematical model assumes an entirely susceptible population… the larger the Ro, the more likely a chain infection will occur

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73
Q

vehicles

A

a mode of transmission reliant on medium/media… common examples include food, air, and water

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74
Q

infectious disease controls directed against common vehicles

A

food laws lowered incidence of foodborne pathogens… water purification reduced incidence of typhoid fever (filtration, chlorination)… airborne pathogens are difficult to control

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75
Q

infectious disease controls directed against reservoir

A

if reservoir is an animal it can be immunized or destroyed…. if reservoir is human then they can be quarantined, immunized, and treated

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76
Q

infectious disease controls directed against transmission of pathogen

A

immunization, quarantine, and surveillance

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77
Q

quarantine

A

restricts movement of an individual with active infection

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78
Q

pathogen eradication

A

goal is to remove all of a pathogen from any reservoirs (ex: smallpox, polio// potentially someday rabies, leprosy)

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79
Q

emergent

A

diseases that suddenly become prevalent

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80
Q

reemergent

A

diseases that have become prevalent after having been under control

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81
Q

emergence factors

A

human demographics and behaviour… technology and industry… economic development and land use… international travel and commerce… microbial adaptation and change… breakdown of public health measures… abnormal natural occurrences

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82
Q

key elements of addressing emerging diseases

A

recognition of disease… intervention to prevent pathogen transmission (methods include quarantine, immunization, and drug treatment)

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83
Q

acquired immunodeficiency syndrome (AIDS)

A

viral disease that attacks immune system… first reported cases were in US in 1981… at least 70 million people have been infected worldwide with HIV and more than 25 million people have died from AIDS… studies in US suggest virus was transmitted through sexual contact or blood… rapid pathogen adaptation and change has contributed to HIV/AIDS epidemic… does not require quarantine

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84
Q

cholera

A

causes severe water-loss diarrhea… typically transmitted through ingestion of contaminated water containing Vibrio cholerae… largely restricted to developing countries… endemic in Africa/Southease Asia/Indian subcontinent/Central and South America… can be controlled by application of water treatment… 100,000 deaths per year

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85
Q

influenza

A

pandemics occur every 10-40 years… caused by major change in influenza genome (antigenic drift and antigenic shift)… occurs cyclically because more strains emerge due to reassortment between bird/swine/and human variants…. ex: 2009 swine flu pandemic (H1N1 influenza)– swine in Mexico simultaneously infected with swine influenza, bird influenza, and human influenza

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86
Q

antigenic drift

A

minor change in influenza viral antigens due to gene mutation

87
Q

antigenic shift

A

major change in influenza virus antigen due to gene reassortment

88
Q

biological warfare

A

use of biological agents to kill a military or civilian population

89
Q

potential candidates for biological warfare

A

can by virtually any pathogenic bacterium or virus… is easy to produce and deliver… safe for use by offensive soldiers… able to incapacitate/kill individuals under attack in a consistent and reproducible manner`

90
Q

anthrax in biological warfare

A

Bacillus anthracis is a preferred agent for biological warfare and biological terrorism because endospores enhance ability to disseminate B.anthracis in aerosols… three forms of disease: cutaneous, gastrointestinal, and pulmonary… anthrax is treated with ciprofloxacin

91
Q

airborne pathogens

A

aerosols are important for person-to-person transmission of many infectious diseases… most pathogens survive poorly in air; thus, they are effectively transmitted only over short distances

92
Q

respiratory infections

A

different pathogens characteristically colonize the respiratory tract at different levels… the upper and lower respiratory tracts offer different environments (temperature, air flow, pH) and favor different microbes

93
Q

upper respiratory tract

A

nasal cavity, oral cavity, pharynx, larynx

94
Q

lower respiratory tract

A

trachea, primary/secondary bronchus, respiratory bronchiole, terminal bronchus, alveolar ducts, alveolar sacs, and alveoli

95
Q

streptococcus pyogenes

A

aka GROUP A STREPTOCOCCI… commonly found in low numbers in upper respiratory tract of healthy individuals… can cause pus-forming wounds… causative agent of STREP THROAT… can also cause infections of inner ear, mammary glands, and skin as IMPETIGO… ERYSIPELAS is an acute streptococcal skin infection… host defenses are weakened or a new, highly virulent strain is introduced… certain group A streptococci strains carry a lysogenic bacteriophage that encodes exotoxins responsible for symptoms of STREPTOCOCCAL TOXIC SHOCK SYNDROME and scarlet fever… untreated or insufficiently treated infections can lead to other diseases (ex: RHEUMATIC FEVER due to molecular mimicry between streptococci’s M protein and host tissue)… occasionally causes sudden and severe systemic infections– CELLULITIS (subcutaneous skin infection) and NECROTIXING FASCITIS (flesh eating bacteria)

96
Q

streptococcus pneumoniae

A

LEADING CAUSE OF BACTERIAL PNEUMONIA… gram positive diplococci (will be present in sputum sample if infected)… virulence factor: ENCAPSULATED strains are pathogenic bacteria because they are harder to kill… treatable by antimicrobial agents (as are group A streptococci) but drug resistant strains are common

97
Q

diphtheria

A

severe respiratory disease that typically infects children… caused by CORYNEBACTERIUM DIPHTHERIAE (a bacterium that forms irregular rods during growth)… preventable and treatable… PATHOGENIC STRAINS OF C. DIPHTHERIAE LYSOGENZIED BY BETA-BACTERIOPHAGE PRODUCE A POWERFUL EXOTOXIN that causes: tissue death due to prevention of protein synthesis and a PSEUDOMEMBRANE in patient’s throat

98
Q

pertussis (whooping cough)

A

an acute, highly infectious respiratory disease… caused by infection with BORDETELLA PERTUSSIS (gram negative, secretes exotoxin)… observed frequently in school-age children… characterized by a recurrent, violent cough… has been a consistent upward trend of infections since 1980s… inadequately immunized children/adolescents/adults are at high risk for acquiring/spreading pertussis

99
Q

tuberculosis

A

caused by Mycobacterium tuberculosis… worldwide infectious disease of humans… incidence is increasing… M.tuberculosis is transmitted by airborne droplets… cell mediated immunity plays a critical role in preventing active disease after infection… classified as a PRIMARY INFECTION (initial infection) or POSTPRIMARY INFECTION (reinfection)… spread of tuberculosis is prevented by: hospitalization of patients in negative-pressure rooms and use of face masks for healthcare workers… treatment: antimicrobial therapy with ISONIAZID; usually involves a nine-month regimen (affects the synthesis of mycolic acid in mycobacteria); directly observed therapy (DOT) is popular in some areas to assure compliance with doctor’s orders and reduce risk of antibiotic resistance

100
Q

leprosy (Hansen’s Disease)

A

is caused by Mycobacterium leprae… armadillo is only experimental animal that has been successfully used to grow M.leprae… most serious form is characterized by folded, bulblike lesions on the body

101
Q

mycobacterium

A

ACID-FAST because of the waxy MYCOLIC ACID content of their cell walls… are multidrug resistant (and extreme-drug resistant)

102
Q

meningitis

A

inflammation of meninges (membranes that line the central nervous system, especially the spinal cord and brain)… can be caused by viral, bacterial, fungal, or protist infections

103
Q

neisseria meningitidis

A

gram negative, nonsporulating, obligately aerobic, oxidase-positive, encapsulated DIPLOCOCCUS… causes one type of infectious bacterial meningitis and a related infection, meningococcemia

104
Q

MMR (measles, mumps, and rubella) and Varicella -Zoster Infections

A

viruses are less easily controlled by chemotherapeutic methods… the most prevalent human infections are caused by viruses… most viral diseases are acute/self-limiting infections… a few serious viral diseases have been effectively controlled by vaccination (ex: smallpox, rabies)

105
Q

measles (rubeola)

A

MOST TRANSMISSIBLE DISEASE… often affects susceptible children as an acute/highly infectious/often epidemic disease caused by a paramyxovirus– negative strand RNA virus (class V)… virus enters nose and throat by airborne transmission…. used to be a common childhood illness but now it occurs only in rather isolated outbreaks (decline is due to widespread immunization programs that began in mid 1960s)… proof of immunization is required for enrollment in US public schools

106
Q

rubella (german measles)

A

caused by positive strand RNA virus (class IV) of togavirus group… disease symptoms resemble measles but are generally milder and less contagious… routine childhood immunization is practiced in US

107
Q

mumps

A

caused by paramyxovirus (like Measles)… highly infectious with occasional outbreaks occurring on college campuses over past 10 years… spread by airborne droplets… characterized by INFLAMMATION OF SALIVARY GLANDS… cured with host antibiotics

108
Q

chicken pox (varicella) and shingles

A

common childhood disease characterized by a systemic papular rash… caused by VARICELLA-ZOSTER VIRUS (VZV)– a herpes virus… VZV is highly contagious and is transmitted by infectious droplets… vaccine is currently used in US… VZV establishes a lifelong latent infection in nerve cells – virus occasionally migrates to skin surface, causing a painful skin eruption (SHINGLES)

109
Q

colds

A

most common of infectious diseases… viral infections transmitted via airborne droplets… infections are usually of short duration… symptoms milder than those of other respiratory diseases… symptoms include RHINITIS, nasal obstruction, watery nasal discharges, and malaise

110
Q

common cold

A

commonly caused by RHINOVIRUSES– positive sense, single stranded RNA viruses (does not cause fever) (nearly 115 different strains identified)… approximately 15% of colds are due to CORONAVIRUSES (alpha primarily, some beta)… approximately 10% of colds are due to other viruses (like adnoviruses, which have fever symptoms)

111
Q

influenza

A

caused by a RNA virus of the orthomyxovrius group… types: A, B, C (with Influenza A being the most important human pathogen)…. subtype range: hemagglutinin (H1-H16) is needed to get into cells and neuraminidase (N1-N9) is needed to get out of cell… H1-H3 and N1-N2 affects humans

112
Q

influenza A

A

highest severity… has animal reservoirs… has 8 genome segments… pandemic population spread…. shift/drift antigenic variation… can be identified by HA + NA surface glycoproteins

113
Q

influenza B

A

intermediate severity… no animal reservoirs… 8 genome segments… epidemic population spread… drift antigenic variation

114
Q

influenza C

A

lowest severity… no animal reservoir… 7 genome segments… sporadic population spread… drift antigenic variation

115
Q

Staphylococcus aureus

A

nonsporulating, gram-positive coccus that divides into several planes to form irregular clumps… causes diseases including acne, boils, pimples, impetigo, pneumoniae, osteomyelitis, carditis, meningitis, and arthritis… many diseases result from pyogenic or pus-forming, infectious or from actions of of staphylococci superantigen exotoxins… pus formation is due to production of leukocidin… is the leading cause of wound infections

116
Q

helicobacter pylori

A

epsilon proteobacteria… gram negative, highly motile, spiral shaped bacterium associated with gastritis, ulcers, and gastric cancers… growth is inhibited by pepto-bismol (containing bismuth)… colonizes the non-acid secreting mucosa of stomach and upper intestinal tract… transmitted via person-to-person contact or ingestion of contaminated food/water

117
Q

hepatitis

A

LIVER inflammation caused by viruses or bacteria… sometimes results in acute illness followed by destruction of liver anatomy and cells (CIRRHOSIS)… restricted group of viruses is associated with liver diseases… types: A, B, C, D, E… vaccines are available for hepatitis A and B viruses but not for other forms

118
Q

hepatitis A

A

INFECTIOUS HEPATITIS… FROM CONTAMINATED FOOD… causes mild or rarely severe cases of liver disease

119
Q

hepatitis B

A

SERUM HEPATITIS… “bloodborne” hepatitis… causes acute, often severe disease that can lead to liver failure and death… has vaccine

120
Q

hepatitis C

A

produces a mild disease initially, but most individuals develop chronic hepatitis that can lead to chronic liver disease… the worst, the “silent killer”… no vaccine

121
Q

hepatitis D

A

DEFECTIVE virus that cannot replicate and express a complete virus unless the cell is also infected with hepatitis B

122
Q

hepatitis E

A

causes an acute, self-limiting hepatitis that varies in severity

123
Q

ebola hemorrhagic fever

A

caused by a filovirus– negative strand RNA virus… transmitted via DIRECT CONTACT with body fluids… major reservoir is likely bats… spread controlled by universal precautions and use of personal protective equipment (PPE)

124
Q

sexually transmitted infections (STIs)

A

aka sexually transmitted diseases (STDs)… caused by a variety of bacteria/viruses/protists/fungi… pathogens are generally only found in body fluids from the genitourinary tract that are exchanged during sexual activity

125
Q

gonorrhea

A

caused by NEISSERIA GONORRHOEAE (gram negative diplococci)… symptoms in females: characterized by a mild vaginitis that often goes unnoticed; untreated it can lead to PELVIC INFLAMMATORY DISEASE… symptoms in males: characterized by a painful infection of urethral canal… prevalent and often asymptomatic in women

126
Q

syphillis

A

caused by Treponema pallidum (SPIROCHETE) often transmitted at same time as gonorrhea… T. pallidum can be transmitted from an infected women to fetus during pregnancy (congenital)… three stages: PRIMARY (open lesion), SECONDARY (rash), and TERTIARY (gumas)… penicillin is highly effective for treating primary/secondary stages… low prevalence and exhibits very obvious symptoms

127
Q

chlamydia

A

LEADING CAUSE OF STIs/STDs… chlamydia trachomatis causes a number of sexually transmitted diseases: nongonococcal urethritis (NGU) and lymphogranuloma venereum (LGV)… can lead to acute complications… elementary bodies = infectious forms

128
Q

herpes simplex 1 virus (HSV-1)

A

infects the epithelial cells around mouth and lips… causes cold sores (FEVER BLISTERS)… may occasionally affect other body sites… spread via direct contact or through saliva… lesions heal without treatment in 2-3 weeks

129
Q

herpes simplex 2 virus (HSV-2)

A

infections are associated with primarily with anogenital region… causes painful blisters on penis of male and cervix/vulva/vagina of females… typically transmitted through sexual contact and most easily transmitted when active blisters are present… genital herpes are currently incurable, however a limited number of drugs are successful in controlling the infectious blister stage

130
Q

human papillomavirus (HPV)

A

causes several different infections: many infections are asymptomatic but some progress to genital warts, can cause cervical neoplasia and a few progress to cervical cancers… THERE IS AN EFFECTIVE HPV VIRUS

131
Q

AIDS

A

recognized as distinct disease in 1981… human immunodeficiency virus (HIV) is causative agent

132
Q

HIV

A

kills immune system by deprivation of helper T cells… as many as 1.1 million people may be infected in US, and worldwide nearly 80 million people have been infected and about 34 million have died

133
Q

CD4 molecule

A

cell surface protein that allows HIV to infect cell

134
Q

HIV treatment

A

four classes of drugs delay symptoms of AIDS and prolong the life of those infected with HIV: NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS, NON-NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS, PROTEASE INHIBITORS, FUSION INHIBITORS… highly active anti-retroviral therapy (HAART) is used but is often too expensive for use in developing countries which are hit hardest by HIV/AIDS

135
Q

zoonosis

A

animal disease transmissible to humans… generally transmitted via direct contact, aerosols, or bites

136
Q

enzootic

A

present endemically in certain populations

137
Q

epizootic

A

incidences reaching epidemic proportions in certain populations

138
Q

rabies

A

epizootic disease in animals but can be spread as a zoonotic disease to humans and can spread from wild animals to pets and from infected pets to humans… reservoirs in US are raccoons, SKUNKS, coyotes, foxes, and BATS (BATS and SKUNKS are major reservoirs in MI)… over 50,000 people die annually (primarily in developing countries)… over one million people receive post-exposure prophylactic care each year

139
Q

symptoms and pathology of rabies

A

RHAABDOVIRUS– negative strand RNA virus that causes rabies; infects central nervous system of warm-blooded animals… leads to death if not treated (can get vaccination before infection causes harm due to its slow progression)… enters body through a wound or bite… in humans, NINE MONTHS may pass before onset of symptoms… virus proliferates in brain and leads to fever, excitation, dilation of pupils, excessive salivation, anxiety, and fear of swallowing

140
Q

hantaviruses

A

cause: hentavirus pulmonary syndrome (HPS) and hemorrhagic fever with renal syndrome (HFRS)… both syndromes caused by hantavirus-infected rodents (most commonly transmitted by inhalation of virus-contaminated rodent excretion (feces))… named for Hantaan, Korea where virus was first recognized as a human pathogen… significant outbreaks have occurred in US: Yosemite camp sites in 2012 and Arizona/Colorado/New Mexico in 1993

141
Q

rickettsias

A

small, alpha-proteobacteria that have strict obligate intracellular existence in vertebrates… associated with blood-sucking arthropods… three types: TYPHUS, SPOTTED FEVER, and EHRLICHIOSIS… CLOSELY RELATED TO HUMAN MITOCHONDRIA… contain minimal sets of genes required for intracellular dependency

142
Q

typhus group: rickettsia prowazelcii

A

transmitted by BODY OR HEAD LOUSE bite that gets contaminated with louse feces

143
Q

spotted fever group: rickettsia rickettsia

A

causes ROCKY MOUNTAIN SPOTTED FEVER… transmitted by DOG AND WOOD TICKS (biological vector)… over 2000 people acquire the disease every year… rickettsia grow in nucleus and cytoplasm… symptoms: headache, fever, and rash

144
Q

Ehrlichiosis and tickborne anaplasmosis

A

emerging diseases are human granulocytic anaplasmosis (HGA) and human monocytic ehrlichiosis (HME), which are spread by tick bites)… flu-like symptoms include fever, headache, malaise, and leukopenia or thrombocytopenia… treatment with antibiotics is usually successful… avoiding hosts and using insect repellants are best measures for reducing chances of exposure

145
Q

Q fever

A

Q STANDS FOR “QUERY”… (influenza like symptoms progress to) pneumonia like symptoms, which are caused by Coxiella burnetii, an intracellular pathogen… transmitted through contact with animals or their products (contaminated WOOL or MEAT or MILK)…. treated with tetracycline… considered a potential bioweapon

146
Q

Lyme Disease

A

affects humans and other animals… cases were first recognized in Old Lyme, Connecticut… MOST PREVALENT TICK-BORNE DISEASE IN US… caused by spirochete BORRELIA BURGDORFERI… symptoms are closely related to symptoms of chronic syphillis… characterized by “bullseye rash”

147
Q

yellow fever

A

caused by yellow fever virus– virus related to Dengue virus, West Nile virus, and encephalitis viruses; transmitted by mosquito bites… endemic disease of tropical and subtropical climates… found in Latin America and Africa… no antiviral drugs are effective… preventable by vaccination

148
Q

dengue fever

A

caused by dengue virus– transmitted by mosquito bites… endemic disease of tropical and subtropical climates… found in Mexico, Latin America, India, Indonesia, and Africa… most infected individuals improve on their own… no antiviral drugs are effective… no vaccine

149
Q

Zika and Chikungunya disease

A

in 2015 Zika appeared in Brazil and has spread throughout South America– Zika can be transmitted form mother to fetus and seems to cause severe neurological problems in the developing embryo (microcephaly or pathological small head)… both Zika and Chikungunya are considered relatively mild diseases carried by MOSQUITOS… symptoms include headache, fever, and general malaise

150
Q

West Nile Virus (WNV)

A

transmitted by mosquito bites… transmission is seasonal… at least 130 species of birds are reservoirs… tend to not be properly identified because symptoms are subacute… no real treatment

151
Q

plague

A

caused more human deaths than any other infectious disease (except malaria and tuberculosis)… caused by Yersinia pestis– gram negative, facultatively aerobic, rod shaped bacterium… fleas are intermediate hosts and vectors that spread it between mammalian hosts… murine toxin is the Yersinia pestis exotoxin that is a respiratory inhibitor and lethal to mice… endemic in ground rodent populations

152
Q

plague

A

caused more human deaths than any other infectious disease (except malaria and tuberculosis)… caused by Yersinia pestis– gram negative, facultatively aerobic, rod shaped bacterium… fleas are intermediate hosts and vectors that spread it between mammalian hosts… murine toxin is the Yersinia pestis exotoxin that is a respiratory inhibitor and lethal to mice… endemic in ground rodent populations… most common form is bubonic (because of buboes that develop in infected individual)

153
Q

sylvatic plague

A

enzootic among rodents

154
Q

pneumonic plague

A

occurs when Yersinia pestis reaches the lungs

155
Q

septicemic plague

A

rapid spread of Yersinia pestis throughout the body… buboes erupt inside body and infects blood

156
Q

anthrax

A

caused by Bacillus anthracis– endospores enhance ability to disseminate B.anthracis (natural reservoir in soils, primarily associated with farm animals)… forms: cutaneous (most common form), gastrointestinal, and pulmonary

157
Q

tetanus

A

serious/often life threatening disease… caused by an exotoxin produced by CLOSTRIDIUM TETANI… natural reservoir is soils… C.tetani gains access to body through soil contaminated wound… result of C.tetani infection on people is LOCKJAW… paralysis extends to rest of body… is preventable because the existing vaccine is completely effective… inadequately immunized individuals are at risk

158
Q

gas gangrene

A

tissue destruction due to proteolysis and gas-producing clostridia… clostridia enter deep tissue through trauma… mainly caused by CLOSTRIDIUM PERFRINGENS… found in soil and intestinal tract of mammals… treatment with antibiotics and HYPERBARIC OXYGEN… AMPUTATION of dead tissue may be necessary

159
Q

eradication of certain diseases is nearly impossible

A

because we cannot control/immunize all vector and reservoir animals or eradicate organisms completely from soil

160
Q

common sources of waterborne disease transmission

A

potable water used for drinking and cooking (undergoes extensive treatment, including filtration and chlorination)… recreational water from public ponds, lakes, swimming pools, etc

161
Q

most important potential common source of infectious disease is

A

water

162
Q

indicator organism

A

presence indicates potential for disease… ex: coliforms (fecal coliforms, such as E.coli, used in water safety testing)– coliforms indicates fecal contamination (as do fecal streptococci)

163
Q

common methods for enumerating water samples

A

MOST PROBABLE NUMBER (MPN) PROCEDURE, MEMBRANE FILTER (MF) PROCEDURE

164
Q

cholera

A

severe diarrhea (death by dehydration)… caused by Vibrio cholerae (primarily infects small intestine)… typically transmitted through ingestion of contaminated water… largely restricted to developing countries (endemic in Africa, Southeast Asia, Indian subcontinent, and Central and South America)… can be controlled by application of water treatment // diagnosis, treatment, and prevention: presence of V.cholerae bacilli in “RICE WATER” STOOLS of patients is key diagnostic test; placement on CHOLERA COT; oral rehydration and electrolyte replacement therapy; individuals traveling to Cholera-endemic regions should avoid drinking water, ice, brushing teeth with tap water, and shellfish

165
Q

legionellosis

A

pathogen of amoeba… normally transmitted in aerosols… gram-negative bacterium– its complex nutritional requirements have led to multiple methods to identify this microbe, including fluorescence microscopy; common in terrestrial and aquatic habitats… relatively resistant to heat and chlorination… legionella pneumophilis is generally transmitted by contaminated water in coolers, pools, domestic water systems

166
Q

typhoid fever

A

the most important pathogenic bacteria transmitted by water are Salmonella enterica serovar typhi and vibrio cholera… SALMONELLA ENTERICA SEROVAR TYPHI causes typhoid fever and has been virtually eliminated in developed countries as a result of water treatment

167
Q

norovirus illness

A

common cause of gastrointestinal illness– symptoms are vomiting, diarrhea, and malaise… transmitted by fecal oral route– most cases are traced in contaminated drinking/recreational water… often cause of mass common source outbreaks on cruise ships and in care facilities… viruses can survive in water for relatively long periods but are inactivated by disinfection with chlorine

168
Q

food spoilage

A

any change in appearance, smell, or taste of food product that makes it unpalatable to consumer… the food’s chemical composition, physical characteristics, and water content determines its susceptibility to microbial spoilage

169
Q

perishable foods

A

typically have higher moisture content and must be stored in conditions to limit microbial growth

170
Q

semiperishable foods

A

foods include foods like fresh fruits and vegetables that must also be stored with care to limit microbial growth

171
Q

nonperishable foods

A

have low moisture content and have a much longer shelf life

172
Q

food preservation

A

slow growth of spoilage microbes… methods include: refrigeration, freezing, heating, drying and dehydration

173
Q

refrigeration

A

slows microbial growth rate and delays spoilage

174
Q

freezing

A

allows for longer storage but isn’t suitable for all foods

175
Q

heating

A

used to reduce bacterial load (PASTEURIZATION) of a product or to actually sterilize it (CANNING)

176
Q

drying and dehydration

A

moisture content (water activity) is critical for microbial metabolic processing– adding sugar or salt reduce water availability for microbial growth

177
Q

fermentation

A

anaerobic catabolism of organic compounds (generally carbohydrates)… important bacteria: lactic acid bacteria, propionic acid bacteria, and acetic acid bacteria… products include yeast bread, cheese, yogurt, buttermilk, sausage, sauerkraut, and soy sauce

178
Q

food poisoning (aka food intoxication)

A

disease that results from ingestion of foods containing preformed microbial toxins… microorganisms that produced toxins do not have to grow in host

179
Q

food infection

A

microbial infection resulting from ingestion of pathogen-contaminated food followed by growth of pathogen in host

180
Q

staphylococcal food poisoning

A

food poisoning is often caused by toxins produced by Staphylococcus aureus– it can grow on common foods and some strains produce heat-stable enterotoxins… gastroenteritis occurs within a few hours of consumption… estimated that 185,000 cases of staphylococcal food poisoning occurs each year… enterotoxins of S.aureus classified as superantigens produce large T cell response and an inflammatory response

181
Q

clostridial food poisoning

A

clostridium perfingens and clostridium botulinum cause serious food poisoning– produce endospores that may not be killed during cooking or canning process (home-canned vegetables cause most common source individual food borne botulism outbreaks)… C. perfingens is most commonly reported form of food poisoning (248,000 annual cases)– large numbers of cells (>10^8) must be ingested; enterotoxin is produced in intestinal tract six to fifteen hours after consumption

182
Q

botulism

A

severe and often fatal food poisoning… caused by exotoxin produced by CLOSTRIDIUM BOTULINUM– botulinum toxin is a neurotoxin but is destroyed by heat… average of 110 cases annually (45% infant cases, 30% wound cases, and 25% foodborne cases)…. home prepared foods are a common source of illness

183
Q

Salmonellosis

A

gastrointestinal illness caused by foodborne Salmonella infection… caused by eating food contaminated with Salmonella or handling Salmonella-infected animals (birds/reptiles)… onset of disease occurs 8-48 hours after ingestion… disease normally resolves in 2-5 days… Salmonella ingested in food or water evades phagocytes and grows as an intracellular pathogen

184
Q

pathogenic Escherichia coli

A

intestinal parasites and a few produce potent enterotoxins… Shiga toxin producing E.coli (STEC) including 0157:H7 produces verotoxin – causes bloody diarrhea and kidney failure… other types of E. coli are enterotoxigenic (ETEC), enteroinvasive (EIEC), and enteropathogenic (EPEC)

185
Q

campylobacter

A

common cause of bacterial foodborne infections in US– more than 2 million cases of bacterial diarrhea per year… transmitted to humans via contaminated food (raw poultry, pork, raw shellfish, or in surface waters)… replicates in small intestine… causes high fever, headache, malaise, nausea, abdominal cramps, and bloody stools

186
Q

listeriosis

A

caused by listeria monocytogenes– intracellular pathogen and is PSYCHROTOLERANT (likes to grow in fridge)… may lead to bacteremia and meningitis… no food product is safe from contamination… uptake of pathogen by phagocytes results in growth and proliferation of bacterium (used actin for movement in cell)… mortality rate is 16%, particularly in pregnant women and fetuses

187
Q

largest numbers of annual foodborne infections are thought to be caused by

A

viruses

188
Q

enteroviruses

A

shed into food/water from feces… examples: poliovirus, norovirus, and HEPATITIS A (and hepatitis E)

189
Q

noroviruses

A

responsible for most infections

190
Q

noroviruses

A

responsible for most infections

191
Q

ROTAVIRUS, hepatitis A, and astrovirus

A

responsible for the rest of infections

192
Q

protists

A

important foodborne diseases are caused by GIARDIA INTESTINALIS, CRYPTOSPORIDIUM PARVUM, and TOXOPLASMA GONDII… can be spread in foods contaminated by fecal matter in water used to wash, irrigate, or spray crops… fresh fruits are often the source of these infections… toxoplasma gondii can be spread by raw or undercooked meat

193
Q

prions

A

proteins that adopt NOVEL CONFORMATIONS that inhibit normal protein function and cause degeneration of neural tissue… variant CREUTZFELDT-JAKOB DISEASE (vCJD)– linked to consumption of meat from cattle suffering with BOVINE SPONGIFORM ENCEPHALOPAHTY (BSE)

194
Q

pathogenic fungi

A

only about 50 fungal species cause disease– fungi can be single celled YEASTS or hyphae-forming MOLDS, while some are DIMORPHIC (meaning they can be either molds or yeasts)

195
Q

major mechanisms through which fungi cause disease

A

ALLERGIC RESPONSES to fungi… MYCOTOXINS (eg AFLATOXINS)… INFECTIONS (MYCOSES)– superficial, subcutaneous, systemic

196
Q

superficial mycoses

A

caused by dermatophytes or fungus living in skin… most common causative agent is TRICHOPHYTON… fungi colonize hair/skin/nails and infect only the surface layers… example: athlete’s foot

197
Q

subcutaneous mycoses

A

situations where fungi colonize deeper layers of skin tend to be more serious than superficial fungal infections… different groups of fungi may cause subcutaneous infection: SPOROTHRIX, FONSECAEA, and CLADOSPORIUM

198
Q

systemic mycoses

A

most serious types of fungal infections… humans become infected by inhaling spores, where fungal growth then occurs in internal organs of body… examples: HISTOPLASMOSIS (caused by Histoplasma capsulation); COCCIDIODOMYCOSIS (caused by Coccidiordes immitis); BLASTOMYCOSIS (caused by Blastomyces dermatidis); PARACOCCIDIOIDOMYCOSIS (caused by paracoccidiodes brasiliensis); CRYPTOCOCCOSIS (caused by Cryptococcus neoformans)

199
Q

pre-disposing conditions for fungal infections

A

impaired immune system or those taking immunosuppressive drugs (ex: AIDS patients)… pregnant women (weakened cellular immune response)… very young and very old individuals (weakened cellular immune response)… antibiotic users (normal microbiota is disrupted)

200
Q

entamoeba histolytica

A

pathogenic protist transmitted to humans primarily through contaminated water and sometimes food… anaerobic and produces resistant cysts… infection can be asymptomatic or lead to diarrhea and/or DYSENTRY (bloody/pus-y diarrhea)

201
Q

naegleria fowleri

A

free living amoeba found in soil and water runoff that can also cause amebiasis… infections usually result from swimming in warm, soil-contaminated natural water sources (hot springs or lakes)… enters human body through nose and burrows directly into brain, causing extensive hemorrhage and brain damage (MENINGOENCEPHALITIS)

202
Q

balantidium coli

A

CILIATED intestinal human and swine parasite… infections caused by cysts… transmitted to humans through fecally contaminated water… symptoms resemble those of amebiasis

203
Q

giardia intestinalis

A

flagellated anaerobic parasite… has mitosomes… produces highly resistant cysts (cysts are capable of withstanding chemical disinfection)… cause of giardiasis, a common waterborne disease… symptoms: explosive, foul-smelling diarrhea, intestinal cramps, nausea, weight loss, and malaise… many individuals exhibit no symptoms and can act as carriers

204
Q

trichomonas vaginalis

A

flagellated anaerobic parasite… transmitted person-to-person by sexual intercourse… no cyst form… can survive on moist surface (can be transmitted by toilet seats, sauna benches, and towels)… vaginal discharge, itching, and burning in women

205
Q

cryptosporidium parvum

A

protist that lives as a parasite in warm-blooded animals… produces thick-walled cells (oocysts) that are shed in the feces of infected animals… oocysts are transmitted in fecally contaminated water…. oocysts are highly resistant to chlorine and UV radiation, thus sedimentation and filtration methods are most effective at removal

206
Q

toxoplasma gondii

A

protist that lives as a parasite in warm-blooded animals… produces oocysts that are shed in feces of infected animals… oocysts are transmitted by cats or undercooked meat… toxoplasmosis is mainly asymptomatic, but can damage eyes/brain/other organs in immune-compromised individuals and/or birth defects… humans are incidental hosts, so infected humans do not transmit disease… can change host behaviour to encourage dispersal

207
Q

malaria

A

protist disease caused by PLASMODIUM spp… has a complex life cycle that includes Anopheles mosquitoes as biological vectors… most common cause of death due to infectious disease worldwide (estimates 350 million infected people and over 1 million deaths annually)… generally found in tropical and subtropical regions… diagnosis requires identifying plasmodium-infected erythrocytes in blood smears… drugs are used to prevent and treat infections (CHLOROQUINE and primaquine)… contained by reducing population of mosquito vector

208
Q

Leishmaniasis- Leishmania tropica or Leishmania mexicana

A

flagellated protozoan… related to Trypanesoma… causes cutaneous leishmaniasis… transmited by bite of sandfly (insect vector)… infects and grows in macrophages… forms nodules and ulcers on skin… treatment with antimony compounds

209
Q

Leishmaniasis- Leishmania donovani

A

causes visceral leishmaniasis… transmitted by bite of sandfly (insect vector)… parasite travels to internal organs… damage to liver, spleen, and bone marrow… if untreated, visceral disease is fatal… treatment includes antimony compounds, bed rest, and blood transfusions

210
Q

Trypanosomiasis- Trypanosoma brucei

A

two subspecies: T. brucei gambiense and T. brucei rhodesiense… causes AFRICAN SLEEPING SICKNESS… transmitted by bite of tsetse fly (insect vector)… parasite multiplies in blood… infects central nervous system and multiplies in spinal fluid… treatment includes anti-trypanosomal drugs

211
Q

Trypanosomiasis- Trypanosoma cruzi

A

causes CHAGA’S DISEASE (american)… transmitted by bite of “kissing bug” (insect vector)… parasite affects heart, gastrointestinal tract, and central nervous system… occurs in Latin American countries

212
Q

schistosomiasis

A

aka snail fever… caused by trematode Schistosoma… eggs released into freshwater -> eggs become miricidia -> miricidia infect snails and become cercaria -> cercaria burrow into skin, leaving skin lesions… occurs in tropical/subtropical countries

213
Q

filariases

A

transmitted by bite of mosquito (insect vector)… called BANCROFT’s FILARIASIS (“elephantiasis”)… caused by nematode WUCHERERIA BANCROFTI… worms interrupt lymph flow… chronic infection of lymphatic system… causes massive enlargement of legs

214
Q

trichinosis

A

caused by nematode Trichinella spiralis… worm lives in muscle tissue of wild mammals… worm infects pigs -> humans eat undercooked meat -> larvae enter intestinal mucosa -> larvae can circulate throughout body

BIO 286 - Microbiology (21 decks)

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