Exam 4 Correct

Naegleria Ameba

(Large Red Cells) in Human Brain Tissue

inflammation of the meninges

Meningitis

Encephalitis

inflammation of the brain

Viral meningitis

more common and mild

Bacterial Meningitis

Death from shock and inflammation -Due to endotoxin (from cell wall of gram-negatives) and cell wall fragments (peptidoglycan, teichoic acid) from gram-positives

Haemophilus influenzae Meningitis

Pathogenicity due to capsule antigen type b, Occurs mostly in children (6 months to 4 years), Prevented by the Hib vaccine

Neisseria meningitidis Meningitis (Meningococcal Meningitis)

Characterized by a rash that does not face when pressed and Vaccination protects against serogroups A, C, Y, W, and B, but not X,

Streptococcus pneumoniae Meningitis (Pneumococcal Meningitis)

Causes pneumonia and otitis media, can be prevented by conjugate vaccine, reduced incidence of pneumococcal meningitis in children by 99%

Listeriosis

Tetanus

caused by clostridium tetani (endospore-forming), tetanospasmin neurotoxin released from dead cells, Prevented by vaccination with a tetanus toxoid (D T a P), Treatment with tetanus immune globulin (T I G)

Botulism

Caused by Clostridium botulinum (Endospore-forming, obligate anaerobe), comes from botulinal exotoxin, Blocks release of the neurotransmitter acetylcholine, causing flaccid paralysis

Fungal: Cryptococcosis

Pathogen: Cryptococcus neoformans, C. grubii, C. gattii entering through the respiratory tract

Bacteria: H. influenzae Meningitis

Pathogen: Haemophilus influenzae, enters through respiratory tract, treated with Capsular Hib vaccine

Bacteria: Meningococcal Meningitis

Pathogen: Neisseria meningitidis and travels through aerosols

Bacteria: Primary Amebic Meningoencephalitis

Pathogen: Naegleria fowleri and treated with Amphotericin B, fluconazole, miltefosine

Leprosy (Hansen's disease)

Caused by Mycobacterium leprae and M. lepromatosis

Rabies

Single-stranded RNA; easily develops mutants, transmitted by the saliva of an animal bite also cross mucous membranes or enter through abraded skin, caused commonly by silver haired bats

Rabies travels

•Virus multiplies in the skeletal muscles and travels through the P N S to the brain cells, causing encephalitis

Rabies

Postexposure prophylaxis (P E P): vaccine plus immune globulin

-Human diploid cell vaccine (H D C V)

-Human rabies immune globulin (R I G)

-In the United States, about 40,000 people receive PEP each year as a precaution following potential exposures

Rabies

Global distribution

In the United States, it occurs in bats, skunks, foxes, raccoons, and unvaccinated domestic animals

Rarely in squirrels, rabbits, rodents

viral diseases with vertical transfer that are harmful to the developing baby include

viral diseases that are harmful to the developing baby include:

-Zika virus disease

-Neonatal herpes

-Cytomegalovirus (C M V) infections

-Rubella

Cryptococcus neoformans Meningitis (Cryptococcosis)

•Soil fungus associated with pigeon and chicken droppings

•Cryptococcus neoformans, as well as C. grubii and C. gattii

•Transmitted by the respiratory route through dried contaminated droppings

African Trypanosomiasis

•Caused by trypanosomes, a type of flagellated protozoa

•Trypanosoma brucei gambiense: Humans are the only reservoir

•T. b. rhodesiense

-Reservoir in livestock and wild animals

-Eastern and southern Africa

Prion

-self-replicating infectious proteins

-Causes normal proteins to abnormally fold

-Transmissible spongiform encephalopathies (T S E)

Prion diseases

•Scrapie: TSE in sheep

•Chronic wasting disease: TSE in deer and elk

•Creutzfeldt-Jakob disease (CJD): TSE in humans

•Kuru: TSE in humans that is caused by cannibalism

•Bovine spongiform encephalopathy (BSE): -Mad cow disease

Gram-Negative Sepsis (endotoxic shock)

•Endotoxins (lipopolysaccharides [L P S]) cause a severe drop in blood pressure

•Klebsiella spp., E. coli, and Pseudomonas aeruginosa are most frequently involved

-Elizabethkingia spp. are an emerging pathogen in this problem area

Gram-Positive Sepsis 2

Group B streptococci (GBS)

▪Streptococcus agalactiae

-Neonatal sepsis

Puerperal Sepsis

•Also called puerperal fever and childbirth fever

-Caused by Streptococcus pyogenes

Rheumatic Fever

•Autoimmune complication of S. pyogenes infections

•Occurs following an episode of streptococcal sore throat

-Group A beta hemolytic streptococci

Burkitt's lymphoma

Symptom is a tumor

•Most common childhood cancer in Africa

-Due to Epstein-Barr virus (human herpesvirus 4)

Fungal sepsis

Pathogen: Candida auris

Signs: Persistent fever and chills

Brucellosis (Undulant Fever)

•Brucella spp.

-Aerobic gram-negative coccobacilli

-Brucella abortus (elk, bison, cows)

-Brucella suis (swine)

-Brucella melitensis (goats, sheep, camels)

Anthrax

•Caused by Bacillus anthracis: endospore-forming aerobic rod

•Found in soil

•Primarily affects grazing animals

•Treated with ciprofloxacin or doxycycline

•Vaccination of livestock

Gas gangrene

-Caused by Clostridium perfringens, a gram-positive, endospore-forming anaerobic rod

▪Grows in necrotic tissue

-Treatment includes the surgical removal of necrotic tissue and/or use of a hyperbaric chamber

Cat-Scratch Disease

•Caused by Bartonella henselae

-Aerobic, Gram-negative

-Inhabits cat R B Cs; carried in the blood of 50% of cats

-Multiplies in the digestive system of cat fleas

▪Cat claws contaminated with flea feces scratch human

Toxoplasmosis

Pathogen: Toxoplasma gondi

Symptoms: Mild disease; initial infection acquired during pregnancy can be damaging to fetus; serious illness in AIDS patients

Reservoir: Domestic cats

Method of Transmission: Ingestion

Plague

•Caused by Yersinia pestis

-Gram-negative rod

-Transmitted by the rat flea (Xenopsylla cheopis)

-Endemic to rats, ground squirrels, and prairie dogs

Plagues

•Bubonic plague

-Bacterial growth in the blood and lymph

-Most common form; 50-75% mortality rate

Relapsing Fever

•Caused by Borrelia spp.

-Spirochete

Lyme Disease (Lyme Borreliosis)

•Caused by Borreliella burgdorferi

•Most common tickborne disease in the United States

•First phase

-Bull's-eye rash; flulike symptoms; occurs in 75% of cases

Antibiotics are very effective during this stage

Spotted Fever Rickettsiosis

•Rocky Mountain spotted fever (tickborne typhus)

-Caused by Rickettsia rickettsii

Classic Viral Hemorrhagic Fevers

•Include yellow fever, Ebola virus disease, Lassa fever, and Marburg virus disease

Emerging Viral Hemorrhagic Fevers

•Ebola virus disease (E V D)

-Caused by the Ebolavirus, a filovirus similar to the Marburg virus

Chagas Disease (American Trypanosomiasis)

•Caused by Trypanosoma cruzi

-Flagellated protozoan

Malaria

•Caused by Plasmodium parasites

•Transmitted by Anopheles mosquitoes

-Plasmodium falciparum: most deadly; severe anemia; blocks capillaries; affects the kidneys, liver, and brain

Leishmaniasis

•Leishmania donovani (visceral leishmaniasis)

-Invades the internal organs

-Often associated with HIV infection

•Transmitted via female sandflies

Babesiosis

•Caused by Babesia microti

•Carried by Ixodes ticks

•Resembles malaria

Normal Microbiota of the Respiratory System

•A number of potentially pathogenic microorganisms are part of the normal microbiota

•Predominating members of the normal microbiota suppress pathogens by competing for nutrients and producing inhibitory substances

•Lower respiratory system is nearly sterile

Epiglottitis

-Caused by opportunists such as Haemophilus influenzae type b

•Streptococcal pharyngitis (strep throat)

-Caused by group A streptococci (G A S)

▪Streptococcus pyogenes

-Resistant to phagocytosis

-Streptokinases lyse clots

-Streptolysins are cytotoxic

•Scarlet fever

-Erythrogenic toxin produced by lysogenized S. pyogenes

Diphtheria

•Caused by Corynebacterium diphtheriae

-Gram-positive rod; pleomorphic

•Prevented by D TaP vaccine

Otitis Media

-Streptococcus pneumoniae

-Nonencapsulated Haemophilus influenzae

-Moraxella catarrhalis

-S. pyogenes

-Respiratory syncytial viruses

The Common Cold

•Over 200 different viruses

-Enterovirus rhinoviruses (30-50%) thrives in temperatures lower than body temperature

Pertussis (Whooping Cough)

•Caused by Bordetella pertussis

-Gram-negative coccobacillus

•Produces a capsule

•Prevented by D TaP vaccine

•Stage 1: catarrhal stage, resembles the common cold

•Stage 2: paroxysmal stage, violent coughing, gasping for air (lasts 1-6 weeks)

Stage 3: convalescence stage,

Tuberculosis

•Caused by Mycobacterium tuberculosis

-Lipids in the cell wall make it resistant to drying and antimicrobials

•BCG vaccine (live, attenuated strain of M. bovis)

Bacterial Pneumonias

•Typical pneumonia: caused by S. pneumoniae

•Atypical pneumonia: Caused by other microorganisms, including mycoplasm

Pneumococcal Pneumonia

•Caused by S. pneumoniae

•Prevented with conjugated pneumococcal vaccine

Haemophilus Influenzae Pneumonia

•Risk group: Children under 5 and adults over 65

-The Hib vaccine reduced the incidence in children by 99%

Mycoplasmal Pneumonia

•Also called primary atypical pneumonia or walking pneumonia

•Caused by Mycoplasma pneumoniae

-No cell wall

•"Fried-egg" appearance on media

•Treated with tetracyclines

Q Fever

•Caused by Coxiella burnetii

Viral Pneumonia

-S A R S - associated coronavirus (S A R S)

▪Emerged in Asia in 2003

Respiratory Syncytial Virus (R S V)

•Most common viral respiratory disease in infants

-Almost all children are infected by age 2

Influenza (Flu)

-12,000 to 52,000 deaths in the United States annually

-1% mortality; usually the very young and very old

•Hemagglutinin (HA) spikes

-Recognize and attach to host cells

Normal Microbiota of the Digestive System (2 of 2)

•Millions of bacteria per milliliter of saliva

•Few microorganisms in the stomach

-Due to H C l production

•Large numbers of bacteria in the large intestine

-Mostly anaerobes and facultative anaerobes

-100 billion bacteria per gram of feces

Dental Caries

•Dental plaque

-Biofilms involved in the formation of dental caries

•700 species of bacteria in the oral cavity

-Streptococcus mutans is the most important cariogenic organism

▪Gram-positive coccus

▪Converts sucrose to lactic acid

▪Produces dextran, a polysaccharide that forms plaque

Periodontal Disease

•Gingivitis

-Inflammation and infection of the gums

-Caused by streptococci, actinomycetes, and anaerobic gram-negative bacteria

Dysentery

Severe diarrhea with blood and mucus

Gastroenteritis

diseases causing inflammation of stomach and intestinal mucosa

Diarrhea

A major cause of infant mortality in developing countries with little or no access to clean water

Shigellosis (Bacillary Dysentery)

•Caused by the genus Shigella and produces shiga toxin

Cholera

Vibrio cholerae and Causes "rice water stools"

•Enterohemorrhagic E. coli (E H E C)

-Produces Shiga-like toxin

Helicobacter Peptic Ulcer Disease

•Caused by Helicobacter pylori and Grows in the stomach acid by producing urease

Mumps

•Prevented with MMR vaccine

Hepatitis

Caused by -Lymphocryptovirus (H H V-4)

-Cytomegalovirus (H H V-5)

-Parvovirus B19 (fifth disease)

-Hepatitis A, B, C, D, E viruses

Hepatitis A

•Hepatitis A virus (Hepatovirus, H A V)

-Single-stranded R N A; lacks an envelope

•Entry via the oral route; multiplies in the lining of the intestinal tract

-Viremia results in spread to the liver, kidneys, and spleen

•Direct person-to-person transmission, vehicle transmission

Hepatitis B

-Double-stranded D N A; enveloped

-Resembles retroviruses

•Transmitted via the blood and bodily fluids

-Up to 1 billion viruses per ml of blood

Acute hepatitis B

-Fulminant hepatitis in 1% of cases

•Transmission: Sexual contact, needles, syringes, mother to baby, contact with blood (risk for health care workers)

•Hepatitis C virus

-Often transfusion-transmitted; donated blood is tested using P C R and tested for H C V antibodies—but may not test positive until 25 days after infection

•Kills more individuals in the United States than A I D S

•May progress for 20 years before symptoms are noticed

-"silent epidemic"

•Transmission: blood and body fluids