Chapter 8: Biology of Infectious Diseases

During a category A HIV infection, the number of helper T cells is_________ the minimum number needed to handle the viral load

greater than

Following exposure to HIV-infected cells, the first cells to be infected in a new host are usually

macrophages

What does MRSA stand for

methicillin-resistant staphylococcus aureus

HIV-1

more virulent and widespread

"First responders"

phagocytic white blood cells

A disease that comes back after a significant decline in incidence is considered to be?

reemerging

How is HIV classified?

retrovirus

Diseases caused by prions

scrapie (in sheep), mad cow disease, Creutzfeldt-Jakob disease

"Barriers to entry"

skin and mucous membranes

Acquired immunodeficiency syndrome is caused by

the human immunodeficiency virus

Human diseases that are caused by viruses

AIDS, chicken pox, influenza, and rabies

Attachment

HIV gp120 binds to CD4 receptor

An emerging virus that was first reported in Saudi Arabia in 2013 in MERS, or Middle East

Respiratory syndrom

Tubercles

a characteristic feature of tuberculosis in the formation of small, hard nodules in the lungs

Outbreak

an epidemic that is confined to a local area

Tuberculosis is likely to be transmitted to caregivers and on long plane flights because

exhales bacteria can be infectious in the air for hours

Components of influenza viruses

hemagglutinin and neuraminidase

All bacteria are_________ that ____________ a nucleus

prokaryotes;lack

Prions are infectious particles made of

protein only

Malaria is caused by organisms of he genus Plasmodium, which are what type of microbe?

protists

Although prion proteins are present in normal tissues, the disease-causing forms are thought to lose their function and to cause disease by

refolding normal prion proteins into a new shape

HIV belongs to which group of viruses, all of which use reverse transcriptase to convert viral RNA to DNA?

retroviruses

Enzymes coded by the HIV genome

reverse transcriptase integrase protease

Antibiotics in the penicillin class kill bacteria by inhibiting production of

the cell wall

Reverse Transcription

viral DNA genome converted into DNA

Integration

viral DNA inserts into host cell genome

The function of bacterial fimbriae relates to

adhering to surfaces

The bacterium that cause tuberculosis is mainly spread by

airborne droplets

There are generally two types of tests for HIV; those that detect the immune system's response are ______ tests

antibody tests

HIV-2

corresponds more closely with a virus in green monkeys

Descriptions of malaria

cyclical pattern of symptoms corresponds with bursting of red blood cells, severe anemia is possible, and can be diagnosed by viewing parasites in blood

Uncoating

After HIV fuses with a host cell membrane, the capsid and protein coats are removed during this process

True or False: Malaria parasites are transmitted by male mosquitoes

False

According to the text, what form of influenza currently has the most potential to create a pandemic?

H5N1

An opportunistic infection is one that takes advantage of what?

a weakened immune system

In the acute phase of HIV infection, the immune system combats the loss of CD4+ T cells by producing as many as 2 billion new T cells a day. This is what model for T cell loss?

"kitchen sink"

Biosynthesis

Cell production viral RNA, and viral proteins

True or False: Antimaterial drugs work like a vaccine, in tat they prevent the human host from becoming infected.

False

Three AIDS-defining opportunistic infections

Mycobacterium tuberculosis Pneumocystis jiroveci pneumonia Toxoplasmic encephalitis

Assembly

New viral particles are made

Pandemic

a global epidemic

A pathogen is a microbe that

is a disease causing agent

Ways in which bacterial resistance to antibiotics can be minimized

take antibiotics as prescribed until all mediation is gone and only prescribe antibiotics for confirmed bacterial infections

Replication cycle in order

1. Virus interacts with receptor on host cell surface 2. Viral DNA or RNA enters cell 3. Viral proteins are translated 4> Viral components, including the capsid, are assembled

Phases of infection with HIV-1B in chronological order, with the earliest step at the top

1. acute phase 2. chronic phase 3. AIDS

Reproductive cycle of HIV life cycle in chronological order

1. attachment 2. fusion/entry 3. reverse transcription 4. integration 5. biosynthesis/assembly 6. budding

As of 2014, about how many people were estimated to be living with HIV infection worldwide?

36 million

An HIV-infected person who has a CD4-cell count less than 200 cells/mm3 and has developed at least 1 of the AIDS-defining opportunistic infections is classified in which CDC category of HIV infection?

C

During the attachment phase of HIV replication, the gp120 spike protein of HIV attaches to what protein on a host cell surface?

CD4

True or False: HIV infection can be cured with highly active antiretroviral therapy (HAART)

False

True or False: Similar to cells, all viruses have DNA as their genetic material

False

True or False: The first documented case of AIDS caused by HIV infection in the United States was in a homosexual man who died in the early 1980s.

False

True or False: Under most circumstances, kissing can treatment HIV

False

Correct descriptions of HIV-1B infection

HIV-1B causes more infections in the United States than HIV-1C does and HIV-1B infects helper T cells and macrophages

Correct statements about Middle East respiratory syndrome (MERS)

It can be transmitted directly between humans, It has a high mortality rate, It infects camels and some bat species, and It was first reported in Saudi Arabia

According to 2014 statistics, which are of the globe has the most people living with HIV?

Sub-Saharan Africa

Malaria is most common in which part of the world?

Sub-Saharan Africa

Reverse transcriptase

The enzyme inside the HIV matrix that catalyzes the conversion of viral RNA into viral DNA

True or False: After the initial infection, a person with acute phase (category A) HIV infection typically asymptomatic

True

True or False: If an HIV antibody test is negative, there is a chance the person can still transmit HIV

True

Which type of microbe is a parasite of cells, is acellular, and bridges that gap between what is considered to be living and nonliving?

Virus

Budding

Virus exits host cell

Which 2 forms of tuberculosis are caused by bacteria that are especially resistant to antibiotics?

XDR TB and MDR TB

Epidemic

a higher than normal occurrence of disease in a certain area over a given period of time

Vector

a living organism, such as a mosquito, that transfers a pathogen from one host to another

A bacterium that is unaffected by an antibiotic drug is said to be

a resistant bacterium

What is bacterial plasmid?

a small, circular piece of DNA separate from the bacterial chromosome

Pilus

bacteria can transfer DNA between cells using this elongated hollow appendage

Fission

bacteria reproduce by this process

Tuberculosis is caused by what type of microbe?

bacterium

Three sings or symptoms that are common in active tuberculosis

chest pains, coughing up blood, and weight loss

Campylobacter jejuni

curved-shaped bacterium that caused food poisoning

During category B HIV infection the CD4 T-cell count _________ while the viral load_________

decreases; increases

During the first few weeks of an HIV-1B infection, the virus typically

generates a high viral load

Functions of bacterial capsules

help to avoid phagocytosis and aid in sticking to surfaces

The immunodeficiency associated with HIV infection is mainly due to a decline in the number of which cells?

helper T cells

Routes through which humans can be infected with H5N1 "bird flu" or avian influenza virus

human-to-human transmission is possible through close contact between chickens and humans

Which body system falls as a result of the Ebola virus?

immune system

Two routes by which influenza virus is commonly contracted

inhaling virus-laden droplets and contact with contaminated objects

"Acquired defenses"

kill infectious agents that gain access to the body; protect against cancer

Flagella

long thin cellular appendages, motile bacteria usually have one or more

MDR TB is ________common than XDR TB, Eastern Europe and Southeast Asia have the highest rates of (MDR/XDR) _______ TB

more common; MDR TB

Latent tuberculosis

most people infected with Mycobacterium tuberculosis have bacteria within tuberculosis, but they lack symptoms and are not contagious

The function of bacterial flagella relates to

motility

During the first 3 weeks of an HIV infection, the HIV antibody test is typically

negative

Approximately what proportion of the world's human population has been exposed to TB?

one-third

Two essential components that all viruses have

outer capsid and inner core with nucleic acid

How much HIV is typically present in the plasma of a person who is sick/dying of AIDS?

over one million viruses per mL of plasma

The most crucial factor in preventing transmission of MRSA is

proper hand-washing

What 2 types of human cells are infected by malaria parasites of the genus Plasmodium?

red blood cells and liver cells

The process of HIV uncoating specifically refers to

release of HIV RNA and viral proteins into a host cell

Pseudomonas aeruginosa

rod-shaped bacterium that causes urinary tract infections

Emerging or new diseases?

severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and avian influenza (H5N1)

Proven practices that minimize the spread of HIV

sex with only a single uninfected partner, use of condoms with every sex partner encounter, sexual abstinence

Factors that affect the HIV prevention strategy, globally

sexual practices, cultural, and belief systems

Staphylococcus aureus

sphere-shaped bacterium that causes toxic shock syndrome

Fimbriae

stiff fibers some bacteria have on their outer surface that help them adhere to host cells

Disease due to a bacterial toxin that prevents muscle relaxation?

tetanus

Stages of HIV infection correct statements

the amount of HIV in plasma rises dramatically in AIDS, CD4 T lymphocyte numbers never recover from their initial drop in the acute phase, during the acute phase, there is an initial burst of HIV replication, during the chronic phase and AIDS, CD4 T lymphocytes decrease steadily

Provirus

the viral DNA, once HIV RNA is reverse transcribed into HIV DNA and integrated into the DNA of a host cells

The diseases and organisms that have been associated with a high degree of antibiotic resistance

tuberculosis, enterococci, staphylococcus aureus, and gonorrhea

Human diseases caused by bacteria

tuberculosis, strep throat, syphilis, tetanus

Fusion/entry

viral envelope fuses with host cell, HIV RNA is released

The common cold, flu, measles, genital warts, and AIDS are human diseases caused by

viruses