Exam 4 Microbiology N251 IUPUI

Epidemiology

the study of the distribution and determinants of diseases and other health outcomes in human population.

also deals with the natural history of diseases and it can provide evidence that contributes to their prevention

health care and planning

tool for investigation of the cause of disease

(defining disease characteristics, such as prevalence, incidence and mortality)

What is the importance of Epidemiology?

identify disease origin

mode of transmission

observe and conduct clinical studies, disease reporting surveys, questionnaires, interviews

What are some of the roles of an Epidemiologist?

scientific method

What is the scientific method?

disease surveillance

Ongoing systematic collection, analysis, interpretation, and dissemination of specific health data for use in public health.

sporadic level

occasional cases occurring at irregular intervals

endemic level

persistent occurrence with a low to moderate level

hyper endemic level

persistently high level of occurrence

epidemic

the occurrence of more cases of a disease than expected for a given time period

a peak in an epidemic curve

pandemic

epidemic spread over several countries or continents, affecting large number of people

epidemiological triangle

used for describing the causality of infectious diseases

provides a framework for organizing the causality of other types of environmental problems

Cholera

an acute intestinal infection caused by ingestion of contaminated water or food

caused cramps, vomiting, diarrhea

blue face, feet

died in less than a day

focus on individual

uses tools for diagnosis

does not take other factors in account

does not form assumptions

does not help in policy formulation

not a qunatitative science

clinical medicine

focus on group

uses tools for community diagnosis

takes into account all factors

forms assumptions/ hypothesis

helps public health policy formulation

quantitative and qualitative science

epidemiology

common source outbreak

people are exposed intermittently or continuously to a common harmful source

point source outbreak

an epi curve with a sharp upward slope and a gradual downward slope

propagated outbreak

an outbreak that is spread from person to person

malaria

giardia

protozoans-single celled eukaryotic organisms

bot fly

tick

arthropods

hookworms

roundworms

pinworms

tapeworms

worms

malaria

Anopheles mosquito

fever, chills, and flu like symptoms

pregnant women are at high risk

can lead to death

giardia

cause of giardiasis

an infection in small intestines

water supply becomes contaminated with raw sewage

arthropods

human bot fly (buries its head inside human skin with butt in air)

south american parasite

adult arthropod

lays egges on

1. blood sucking vector --> larvae enters host after vector takes a blood meal

2. on human skin

then eggs become larva or can be pupa in soil

start all over again

What is the life cyle of an arthopod?

ticks

carry several types of diseases

Rocky mountain spotted fever

lyme disease

anaplasmosis

Spring: eggs

Summer: larva - first blood meal

Fall: larva

Winter: larva

Spring: nymph

Summer: second blood meal

Fall: third blood meal

What's the two year life cycle of a tick?

hookworms

small worms that enter through the skin and eventually migrate to small intestines

they enter the body body from outer environment (soil, grass)

makes its way to lungs through circulatory system, coughed up, and swallowed and ends up in intestines

eggs are passes in feces and ends outside again

Life cycle of worms in general

roundworms

large intestinal nematode

very common: may infect 25% of world pop.

12-40 cm long

transmitted via stools of infected people, dirty hands, unwashed fruits and veg

eggs can lay in soil for years

lie in small intestine but can crawl around (coming out of nose or climbing up a tear duct

large numbers can block the intestine

they absorb nutrients leading to nutrient def.

pinworms

most common nematode infection

its complete life cycle occurs in human host

the female worm lays eggs around child's anal area

child scratches area and gets eggs under fingernails (fomite) spreads eggs

Enterobiasis (Pinworms)

anail itching, esp at night, can lead to PID or vaginitis

tapeworms

the intestinal worm

parasite of dogs or farm animals, transmitted fecal-orally.

transmission can occur if a domesticated farm dog eats infected carcass and then transmits it to food crops of directly to humans

- Eukaryotes

- Heterotrophs

- Cell wall made of chitin

- multinucleated cells

- NO chloroplasts

What are the characteristics of Fungi?

- Eukaryotes

- Autotrophs

- Cell wall made of cellulose

- Single-celled nuclei

- HAS CHLOROPLASTS

What are the characteristics of plants?

Leaves, stems, roots

chlorophyll

What are things fungi do not have, but plants DO have?

An external carbon source (heterotrophic)

What do fungi require in order to live?

identification

The cell wall of fungi is made up of chitin. What does this aid in?

yeasts

Type of fungi that are singled celled fungal forms

molds

type of fungi that has multiple cells forming a filamentous mycelium

spores

type of fungi are reproduced by spores (sexually/asexually)

morphology, arrangement and mode of derivation of spores

What are good criterias for genus and species identification of spores?

spore - germ tube - hypha - mycelium

What are the different stages of molds?

found in nearly every habitat on earth where organic materials exist

What is the habitat of fungi?

1. Allergic reaction

2. Reaction to toxin

3. Fungi that destroy human food supply

4. Colonization in human body

What are the 4 ways fungi can disease/affect humans?

allergic reaction

exposure to fungi causes person to become sensitized (immediate hypersensitivities)

reaction to toxin

exposure to fungi causes

- hallucinogenic properties of some mushrooms

- poisonous effects of ergot fungus (ryre smut)

- carcinogenic toxins of Aspergillus (aflatoxins)

Ergoitism on wheat stalk/rye

Ergot fungi causes what?

Ergotism

severe pathological syndrome affecting humans or animals that have ingested plant material containing ergot alkaloid, such as ergot-contaminated grains.

hallucinations

irrational behavoir

convulsions

death

The neurotropic activities of the ergot alkaloids may cause what?

induce uterine contractions and control bleeding after childbirth

What does Ergometrine (from Ergot) used for?

Wheat rust

puccinia graminis

Dutch elm disease

Ceratocystis ulmi

Potato blight

Phytophthora infestans

Aspergillus

Cause of Aspergillosis

superficial mycoses

intermediate mycoses

systemic mycoses

What are the different levels of fungal colonization of the human body?

nasal sinuses

lungs

blood vessels (injury/catheters)

oesophagus

stomach

intestine

skin

What are some routes of entry for fungal contamination?

brains

lungs

heart

spleen

liver kidney

What are some areas of deep mycoses for fungal contamination?

- Candidiasis (thrush, vaginal)

- Dermatophytes (athel. foot, Tinea capitis, jock itch, nails)

- Sporotrichosis (gardener's hazard)

- Blastomycosis (skin)

What are some example of superficial mycoses?

Candidiasis (caused by Candida albicans (Yeast))

What is the fungus that causes thrush or yeast infections?

Athlete's foot (tinea pedis)

common skin infection between toes and soles of feet

may spread to palms, groin, and body

causes itching, scaling and redness

may blister in severe cases

- Aspergillus

- Candidiasis

- Cryptococcus

- All dimorphics

- Mucormycosis

What are some fungi that can cause intermediate mycoses?

- Mucormycosis

- Aspergillosis

- Candidiasis

- Cryptococcus

- All dimorphics

What are some fungi that can cause systemic mycoses?

Aspergillosis

name given to wide variety of diseases caused by infection of fungi Aspergillus

most cases occur in people with underlying illnesses (TB, chronic obstructive pulmonary disease), people with deficient immune systems

Dimorphics

mycotic organisms that posses different morphological forms under different temperature conditions

- histoplasmosis

- blastomycosis

- coccidiomycosis

Murcormycosis

a serious but rare fungal infection caused by a group of MOLDS.

They live throughout the environment

Affects people with weakened immune systems and can occur in nearly any part of the body

Cryptococcus neoformans

a fungus that lives in the environment throughout the world.

people become infected after breathing in the microscopic fungus

extremely rare in people who are otherwise healthy; most occur in people with weakened immune systems

- Fungi as useful tools for genetic and biochemical studies

Neurospora crassa:

Yeasts:

human insulin

growth hormone

somatostatin

vaccine against viral hepatitis

- Fungi as food:

mushrooms

alcohol, breads

- Fungi in symbiosis:

linchens

How can fungi be good?

skin scrapings, hair and nail clippings

tissue imprints or sections

- special stains

What are direct observations in lab diagnosis of fungal infections?

handling of specimens in prep for culture

How are cultures used in fungal lab diagnosis of fungal infections?

Sabouraud's dextrose agar

Not-selective media for fungi

Mycobiotic agar

Sabouraud's with anitbiotics agar

Cyclohexamide agar

Selective media for fungi

Brain heart infusion with blood agar

Potato dextrose agar

Enriched media for fungi

Lactophenol Aniline Blue

In mount preparation slides for mold, what dye is used?

- yeast-like (creamy, pasty to mucoid)

- mold (cottony to wooly)

- rate of growth

- colony pigmentation

- growth on media containing anti fungal agents

- dimorphic growth

- mount prepations (molds)

*tease mount

* scotch tape mount

What are some preliminary isolate observations for fungal identification?

subculture

biochemical

DNA techniques to aid in identification

What are some things that can be done for fungal identification?

prion

contains only protein material

prion

a type of protein that can trigger normal proteins in the brain to fold abnormally

by infected meat products

Prion diseases can affect both humans and animals. How can prion diseases be spread to human?

Prion Hypothesis

suggests that an abnormal conformer (PrPSc) of the cellular prion protein (PrPc) is capable of inducing PrPc to undergo a change of conformation into PrPSc

Brain looks spongy because of the tissues that were destroyed

What does prion folding do?

Bovine Spongiform Encephalopathy

Chronic Wasting Disease

Scrapie

What are some examples of prions found in animals?

Bonvine Spongiform Encephalopathy

a chronic degenerative disease affecting the central nervous system of cattle

"Mad cow disease"

they were fed left over cow meat that had been infected

humans get the disease from eating the contaminated meat (primarily in the brain or spinal cord tissue)

How do cows get bovine spongiform encephalopathy?

How do humans get it?

Chronic Wasting Disease

prion disease in elk and deer

causes them to walk as if they are "drunk"

currently being monitored in Indiana

Creutzfeldt-Jakob disease (CJD)

- prion in humans

- caused by abnormal prions that are not killed by standard methods of sterilizing surgical equipment

- causes those to lose ability to think and move properly and suffer memory loss. The brain SHRINKS

always fatal

1. sporadic/classical - unknown cause

2. familial/infectious - inherited mutation in genes

3. Iatrogenic - contamination in hospital

4. variant - exposure to BSE

What are the four different types of CJD?

Kuru

prion disease in New Guinea by the Fore tribe

After passings, brains were consumed by women and children. (cannibalism)

Symptoms: headache, joint pain, difficulty walking, death

viroids

Infectious particles that cause disease in plants

made up of genetic material

no protein coat

only a little larger than prions

potato spindle viroid

spread through contact between plants

virus

a submicroscopic particle made up of nucleic acid that replicate inside living cells using the cellular synthetic machinery for production of progeny virions

either RNA or DNA, NEVER BOTH!

host range

range of animal spp and tisue cells that a virus can infect (can be broad or limited)

capsomeres

morphological subunits from which the virus capsid is built

determines the shape of virus

capsid

protein shell or coat that encloses nucleic acid genome (virus)

envelope

lipid-containing membrane that surrounds some viruses

nucleocapsid

capsid together with enclosed nucleic acid

virion

complete infective virus particle (synonym)

incomplete virion

virion without nucleic acid (empty capsid)

pseudovirion

during viral replication, capsid sometimes encloses host nucleic acid rather than viral nucleic acid; looks like ordinary virus particles when observed by electron microscope, but do not replicate

provirus

viral DNA that is inserted into host cell chromosome in latent state and must be activated before it is transcribed, leading to production of progeny virions;

transmissible from parent cell to daughter cell

- made up of nucleic acid & has a capsid (protein coat)

- very small in size (smaller than even E. coli) and contains very few genes

- contain either RNA or DNA (not both)

- lack cellular components needed to generate energy & synthesize proteins (need host)

- contain few enzymes

- contain min. amount of genetic info

What are the general characteristics of a virion (bacteriophage)?