Questions covering Lecture 13 and 14 Person to Person Bacterial and Viral Diseases

_____ are important for person-to-person transmission of many infectious diseases. Most pathogens survive poorly in the air, so _____.

-aerosols

- they are effectively transmitted only over short distances

Different pathogens characteristically colonize the respiratory tract at different levels, The ____ and ____ respiratory tracts offer different environments and favor different microbes.

- upper and lower

What is the major species in group A streptococci, commonly found in low numbers in the upper respiratory tract of healthy individuals? What wounds do they form?

- Streptococcus pyogenes

- pus-forming wounds

Streptococcus pyogenes

causative agent of _______.

Can also cause infections of the inner ear, mammary glands, and skin as ____. When do infections occur?

- strep throat

- impetigo

- if host defenses are weakened or a new highly virulent strain is introduced

Certain group A streptococci strains carry a _______ that encodes _____ responsible for the symptoms of what two diseases?

- lysogenic bacteriophage

- exotoxins

1- streptococcal toxic shock syndrome

2- scarlet fever

(untreated or insufficiently treated infections can lead to other diseases, rheumatic fever)

untreated or insufficiently treated infections can lead to other diseases, given an example. What is an uncommon infection that results?

- rheumatic fever

- necrotizing fasciitis (flesh-eating bacteria)

Streptococcus strains are definitely diagnosed by culture. The more virulent types are _______. The complete hemolysis on a blood agar plate, is caused by an ______.

- beta-hemolytic

- exotoxin

Both ________ and _________ are treatable by antimicrobial agents, but drug resistant strains of ______ are common.

- group A streptococci

- S. pyogenes

- S. pneumoniae

Streptococcus

Diagnostics:

Virulence:

- complete hemolysis

- hemolysin toxin

Pertussis (whooping cough)

An acute, highly infectious, ______ disease

Caused by infection with __________.

Observed frequently with what audience?

Characterized by what?

There has been a consistent upward trend of infections since the _____.

What is the vaccine?

Who is at high risk for acquiring and spreading pertussis?

- respiratory

-Bordetella pertussis

- school-age children

- recurrent, violent cough

-1980s

-prevention antibiotics

-inadequately immunized children, adolescents, and adults

What is the diagnosis of pertussis?

What is the prevention of pertussis?

Treatment of pertussis?

1- made by fluorescent staining of a nasopharyngeal swab specimen

2- vaccine soon after birth

3- antibiotics but elimination is helped by the immune response

Tuberculosis

- worldwide infectious disease of humans, incidence is increasing

M. tuberculosis is transmitted by _________. ______ plays a critical role in preventing active disease after infection. It is classified as what two types of infections?

- airborne droplets

- cell mediated immunity

- primary infection (initial infection) or post primary infection (reinfection)

Primary Infection with tuberculosis. ________ the patient to the bacteria and alters _________ to subsequent exposures How is hypersensitivity measured?

- hypersensitizes

- the individual's response

- measured by a diagnostic skin test

Postprimary infection with Tuberculosis. Chronic tuberculosis results in a gradual spread of _________.

a gradual spread of tubercular lesions in the lungs

How is the spread prevented? What is the treatment?

- hospitalization of patients in negative pressure rooms and use of face masks by healthcare workers

- antimicrobial therapy with isoniazid

The treatment of antimicrobial therapy usually requires a ________ regimen. affects the synthesis of _____ in mycobacteria. What is a downside to this?

- 9 month

- mycolic acid

- resistance of M. tuberculosis to isoniazid and other drugs is increasing especially in HIV/AIDS patients

Leprosy (Hansen's Disease)

What is the causative agent?

What is the more serious form?

How is it characterized?

- M. leprae

- lepromatous leprosy

- folded bulblike lesions on the body; especially on cooler parts of the body such as the face and extremities

What are the lesions due to?

the growth of M. leprae cells in skin Schwann cells that insulate the nerves, and the lesions contain larger numbers of bacterial cells.

Why are the most prevalent human infections caused by viruses? Most viruses are ____,____ infections. A few serious viral diseases have been effectively controlled by vaccination.

- The viruses can often remain infectious for long period of time in dried mucus

- acute, self-limiting

Measles

who does it affect?

what is it caused by?

How is it characterized?

- affects susceptible children as an acute highly infectious, often epidemic disease

- paramyxovirus

- a light pink rash that progresses

Measles used to be a common childhood illness, but now _______. Why did it decline? Over the past decade it reappeared presumable because?

- occurs in isolated outbreaks

- widespread immunization programs in the mid 1960s

- in populations not immunized or inadequately immunized

In 2010, ___ cases of measles were reported in the U.S. In 2019 ____ cases of measles confirmed, which was the highest incidence in nearly 30 years.

- 63

-1044

Rubella

what is it caused by?

what are the disease symptoms?

- caused by a positive strand RNA virus of the togavirus group

-resemble measles but are milder and less contagious

Mumps

what is the cause of pumps?

how infectious is it?

- paramyxovirus

- highly infectious with occasional outbreaks

For Mumps, the occasional outbreaks affected many ______. The recommendations for immunizations were revised to who? what are the disease symptoms?

- young adults (18-34)

- healthcare workers, school-age children, and some adults

- inflammation of salivary glands

An attenuated mumps vaccine (part of the MMR) is highly effective in ______. The prevalence of mumps in _____ is low.

- preventing disease

- developed countries

Chicken Pox (varicella)

what is it characterized by?

what is it caused by?

How is it transmitted?

Is there a vaccine?

- common childhood disease characterized by a systematic papular rash

- varicella-zoster virus (VZV), a herpesvirus

- infectious droplets

- yes

The chicken pox (varicella) virus establishes a lifelong ____ infection where? The virus occasionally migrates to the skin surface, causing what?

-latent infection

- a painful skin eruption known as shingles

(Chickenpox is usually a milder illness that affects children. Shingles results from a reactivation of the virus long after the chickenpox illness has disappeared.)

Shingles most commonly strikes what types of people? The vaccine containing the concentrated attenuated virus called ____ is available for individuals over 50 years.

- immunosuppressed or elderly

- Zostavax

The Zostavax vaccine keeps VZV from migrating out of _____ to skin cells and therefore _________.

- nerve ganglia

- triggering shingles symptoms

the common cold is caused by _____. These are positive-sense, single stranded ____ viruses. There are nearly 150 different strains identified. It is a viral infection transmitted via _______. Symptoms include.

- rhinoviruses

- RNA

- airborne droplets

- rhinitis, nasal obstruction, watery nasal discharges, and malaise

About ___ of colds are due to infections with other viruses. These include the _____ and ______. Most antiviral drugs are _____ against the common cold.

- one third

- adenoviruses

- coronaviruses

- ineffective

Influenza viruses contain a single stranded _____ segmented RNA genome surrounded by an envelope composed of what three things?

- negative sense

- protein

- lipid bilayer

- external glycoproteins

What are the three different types of influenza viruses?

A,B, and C

Influenza A is the most important human pathogen

Each strain of influenza A can be identified by a unique set of surface glycoproteins. What are the two?

- hemagglutin (HA or the H antigen)

- neuraminidase (NA of the N antigen)

eahc viruse has one type of HA and one type of NA on its _______ and it is named for the antigens it contains.

- viral capsid

The HA antigen is important in ______ the influenza virus to host cells. The NA antigen is instrumental in _____ the viruse from the host cell.

- attaching

- releasing

Why do influenza outbreaks occur annually?

They occur because of the plasticity of the influenza genome.

minor change in influenza virus antigen sdue to gene mutation

antigenic drift

major change in influenza virus antigen due to gene reassortment

antigenic shift

Influenza epidemics and pandemics occur periodically. What are some examples?

1- the 1957 outbreak of Asian flu

2- Pandemic influenza A (H1N1) 2009 virus (swine flu)

3- Influenza A H5N1 (bird flu)

What are two ways of prevention for influenza?

1- immunization

2- careful worldwide surveillance

What is a treatment for influenza? When is it most effective and what should be avoided?

- use of various drugs, such as Tamiflu

- It is most effective when it is administered early because they limit the spread of the virus from cell to cell.

- aspirin should be avoided because it may lead to Reye's syndrome

a nonsporulating, gram-positive coccus that divides into several planes to form irregular clumps

Staphylococcus

a salt tolerant, catalase positive, facultative aerobe

Staphylococcus

Staphylococcus can ferment if ________. What can it ferment? What does it form?

- if no acceptors are present

- mannitol (differential media), sucrose, maltose, coagulase positive

- forms golden colonies

What several diseases do Staphylococci cause?

- acne

-boils

-impetigo (also caused by Strep. pyogenes)

-pneumonia

-osteomyelitis

- endocarditis

- meningitis

- arthritis

Many diseases result from _____ infection or from the actions of staphylococcal superantigen exotoxins such as ______. What are some other exotoxins?

- pyogenic (pus forming)

- TSST-1

- enterotoxin (picnic bacterium: cause of food poisioning)

- exfoliatin (skolded skin syndrome)

How are virulence factors of S. aureus important from person to person?

1) disable immune systems

2) colonization

3) disease induction

S. aureus disables the immune system trhough the actions of what?

1- surface proteins (protein A)

2- coagulase (exoenzyme)

3- hemolysis toxin (beta hemolysis- complete destruciton of red and white blood cells)

How does S. auerus act as a virulence factor through colonization?

They have invasive proteins called hylauronidase that brurrow through tissues

How does S. aureus as a virulence factor through disease induction?

- exotoxin

- exfoliatin

- enterotoxin

- TSSt-1

S. aureus can be isolated using what media?

a differential and selective media in one (MSA) mannitol salt agar

a gram negative, highly motile, spiral shaped bacterium

Helicobacter pylori

What diseases are associated with Helicobacter pylori?

- gastritis

- ulcers

- gastric cancers

- gastric adenocarcinoma

Where does it colonize?

it colonizes the non acid-secreting mucosa of the stomach and upper intestinal tract

What causes the immune system escape in Helicobacter pylori?

- the LPS which causes low immunogencity

- The Cag A "oncoprotein" that supresses phagocytosis and blocks T cell response

- catalase which supresses the production of ROS by macrophages

What causes the colonization?

- urease

-flagella

-adesive proteins

What causes the disease induction for gastric inflammation and cancer?

CagA

What causes the disease induction for ulcer?

dupA (duodenal ulcer promoting protein)

These diseases are transmitted via person to person contact or ________, how many people have it?

- ingestion of cntaminated food or water

- 1/3

How do we diagnose this?

- a urease breath test

- PCR in stool sample (precise)

STIs also called STDs are caused by a variety of bacteria, ____, ____, and even ____. The pathogens are generally only found in _________.

- viruses

- protists

- fungi

- genitourinary tract that are exchnaged during sexual actvity

What are the two preventable and treatable bacterial STIs

Gonorrhea and syphilis

____ is prevelant and often asymptomatic in women. ____ has very low prevelance and exhibits very obvious symptoms.

- Gonorrhea

-syphilis

Gonorrhea is caused by ________ (intracellular) and what is the morphology? What are the symptoms in males and females?

- Neisseria gonorrheae

- gram negative cocci

males :

- painful infection of the urethral canal

females:

- mild vaginitis and goes unoticed

- untreated gonorrhea can lead to pelvic inflammatory disease

- virulence factors include colonization (pili and production of LPS)

females:

What are the virulence factors?

- virulence factors include colonization (pili and production of LPS)

Syphillis is caused by _____ and if often transmitted at the same time as gonorrhea. It can be transmitted from an infected woman to the fetus during pregnancy. what is this known as? What are the three stages?

- Treponema pallidum

- congenital syphilis

- primary, secondary, and tertiary

____ is highly effective for the primary and secondary stages.

penicillin

_____ causes a number of sexually transmitted diseases. What are they known as? it is the most prevelant bacterial STI in the world.

- Chlamydia trachomatis

- nongonoccal urethritis

- lymphogranuloma venerum

____ infects the epithelial cells around the mouth and lips. What are the symptoms? How is it spread? How long is the healing process?

- Herpe simplex 1 virus (HSV-1)

- causes cold sores (fever blisters) and ocassioanly other body sites

- spread via direct contact or through saliva

- the lesions heal without treatment in 2-3 weeks

In _____ the infections are associated primarily with anogential region. What are the symptoms? How is it spread? What is the cure?

- Herpes simplex 2 virus (HSV-2)

- causes painful blisters on penis of male and servic, vuvla or vagina of females

- spread through sexual contact and most easilt transmitted when active blisters are present

- currently incurable but ther are drugs to help in controlling the infectious blister stage

In the _______ many infections are asymptomatic but sometimes it can progess to genital warts. It can cause ______ which can then progress into ______. What is a vaccine?

- human papillomavirus

- cervical neoplasia

- cervical cancer

- 9-valent vaccine (Gardasil)

Acquired immunodefiency syndrome (AIDS) was recognized as a distinct disease in ______. What is the causative agent?

- 1981

- the human immunodefiency viruse (HIV)

The HIV infection does not immediatly kill the host cell but instead does what?

the infection results in a progressive decline in CD4 cells

As the number of CD4 cells declines, ____ production falls which then leads to the reduction of what?

- cytokine production

- immune response

HIV infection can be diagnosed with immune testing such as ____ or rapid tests which detects what? what is the downside to a rapid test?

- HIV-EIA

- the antibodies

- these fail to detect infection in individuals who recently acquired HIV (no antibodes)

____ can detect HIV RNA directly from blood and # of viruses as well- useful for early detection.

RT-PCR

HIV infects cells that contain what kind of cell surface?

the CD4 cell surface protein: T helper cell (carried CD4) and some coreceptors (macrophages are also detected)

What four classes delay the symptoms of AIDS and prolong life.

1- nucleoside reverse transcriptase inhibitors

2- nonnucleoside reverse transcriptase inhibitors

3- protease inhibitors

4- fusion inhibitors

What type of therapy is used but is often too expensive for use in developing countries?

Highly active anti-retroviral therapy

Preventing the spread of HIV infection requires what?

education and avoidance of high-risk behavior