Skin, Eye, Respiratory, Urogenital, Digestive, Circulatory, and Nervous System Infections

Comprehensive practice flashcards covering etiology, symptoms, pathology, and prevention for various human microbial diseases as detailed in the lecture notes.

Furuncles & Carbuncles

Bacterial skin infections caused by Staphylococcus aureus characterized by swelling and pus-filled deep lesions; a carbuncle is formed by multiple merged furuncles.

Scalded Skin Syndrome

A Staphylococcus aureus infection where Toxin A and Toxin B cause the separation of epidermal layers, leading to large sheets of skin peeling off.

Impetigo

A superficial epidermal infection caused by Staphylococcus aureus or toxins, characterized by nonbullous crusting sores.

Erysipelas

A Streptococcus pyogenes infection deep in the dermal layer that presents as reddish patches with raised margins.

Necrotizing Fasciitis

A "flesh eating" bacterial infection caused by Streptococcus pyogenes toxins that destroy muscle fascia and tissues, often inducing Streptococcal TSS.

Cutaneous Mycoses (Ringworm)

Fungal skin infections caused by Dermatophytes (Trichophyton, Microsporum, Epidermophyton) that colonize dead keratinized tissues.

Trachoma

A bacterial eye infection caused by Chlamydia trachomatis where eyelid scarring causes eyelashes to scratch the cornea, leading to blindness.

Acanthamoeba Keratitis

A protozoan eye infection associated with freshwater, tap water, or improper contact lens care, causing severe pain and corneal damage.

Streptococcal Pharyngitis (Strep Throat)

Upper respiratory inflammation caused by Streptococcus pyogenes, featuring tonsillitis, fever, and virulence factors like M-protein and Streptolysins.

Scarlet Fever

Systemic toxemia following pharyngitis caused by Streptococcus pyogenes carrying an erythrogenic exotoxin; symptoms include "strawberry tongue" and a hypersensitive rash.

Diphtheriae

Respiratory infection caused by Corynebacterium diphtheriae characterized by the formation of a pseudomembrane in the throat that blocks air passages.

Pertussis (Whooping Cough)

Lower respiratory infection caused by Bordetella pertussis; tracheal cytotoxin kills ciliated cells, leading to violent coughing fits and mucus buildup.

Tuberculosis (TB)

A persistent lower respiratory infection where Mycobacterium tuberculosis survives inside macrophages, which wall off the bacteria to form lung "tubercles" (granulomas).

Mycoplasma Pneumonia

Also known as "walking pneumonia," this lower respiratory infection is caused by wall-less pleomorphic bacteria and is common in children and young adults.

Legionellosis

A potentially fatal pneumonia caused by Legionella pneumophila, which multiplies intracellularly inside water-bound amoebas and is spread via aerosols like AC exhaust.

Influenza (The flu)

A viral lower respiratory infection caused by enveloped RNA viruses with H (hemagglutinin) and N (neuraminidase) spikes that undergo antigenic shifts and drifts.

Chickenpox & Shingles

Diseases caused by Varicella-zoster virus (HHV3); the virus remains latent in the dorsal root ganglia after the initial infection and can reactivate later in life as painful vesicles along sensory nerves.

Measles (Rubeola)

A highly contagious viral disease characterized by a macular rash and Koplik's spots in the oral cavity.

Coccidioidomycosis

Also known as San Joaquin Valley fever, this fungal lung infection is caused by Coccidioides immitis and is endemic to the Southwestern United States.

Cystitis

Inflammation of the urinary bladder, typically caused by E. coli, resulting in dysuria, pyuria, and hematuria.

Gonorrhea

A bacterial STI caused by Neisseria gonorrhoeae, using fimbriae for attachment and Opa proteins to prevent $CD4+$ T-cell proliferation.

Pelvic Inflammatory Disease (PID)

Extensive inflammation of female pelvic organs, such as the uterine tubes (salpingitis), often caused by Neisseria gonorrhoeae and Chlamydia trachomatis.

Syphilis

A multi-stage bacterial STI caused by Treponema pallidum; primary stage features a chancre, secondary features a rash, and tertiary features gummas.

Trichomoniasis

A protozoan STI caused by Trichomonas vaginalis, often resulting in a greenish-yellow discharge and frequently occurring as a coinfection with gonorrhea.

Shigellosis (Bacillary Dysentery)

Bacterial GI infection characterized by severe bloody dysentery and abdominal cramps, caused by Shigella species producing Shiga toxin.

Typhoid Fever

A systemic infection caused by Salmonella enterica Typhi that colonizes the gallbladder and causes a high sustained fever of $104^{\circ}\text{F}$.

Cholera

Infection by Vibrio cholerae where the cholera toxin causes "rice water" stools and massive loss of fluid and electrolytes like Potassium.

Helicobacter Peptic Ulcer Disease

Condition where Helicobacter pylori secretes urease to neutralize stomach acid, leading to inflammatory ulcers in the mucosal lining.

Giardiasis

Protozoan GI infection caused by Giardia lamblia, featuring prolonged flatulence with $H_{2}S$ ("rotten egg") gas and weight loss.

Amoebiasis (Amoebic Dysentery)

Severe bloody dysentery caused by Entamoeba histolytica trophozoites that aggressively feed on gastrointestinal epithelial tissues.

Rheumatic Fever

An autoimmune complication following pharyngitis where anti-streptococcal antibodies accidentally damage human heart valves through molecular mimicry.

Gas Gangrene

An anaerobic infection of necrotic tissue caused by Clostridium perfringens, characterized by foul-smelling wounds and visible gas bubbles.

Plague

A vector-borne disease caused by Yersinia pestis, characterized by buboes and necrotic "black toes," transmitted by fleas from rodent reservoirs.

Rocky Mountain Spotted Fever

A tick-borne bacterial infection caused by Rickettsia rickettsii, featuring a measles-like rash that uniquely begins on the palms and soles.

Lyme Disease

A condition caused by Borrelia burgdorferi transmitted by deer ticks; characterized by a bull's-eye rash in Phase 1 and chronic arthritis in Phase 3.

HIV/AIDS

A viral infection where gp120 binds $CD4$ receptors on Helper T cells, eventually causing clinical AIDS when $CD4+$ counts drop below $200\,\text{cells}/\mu\text{l}$.

Malaria

A protozoan circulatory infection caused by Plasmodium species, characterized by paroxysms of chills and fever every 48–72 hours as merozoites rupture red blood cells.

Meningococcal Meningitis

Bacterial meningitis caused by Neisseria meningitidis, starting as a throat infection followed by a rash that does not fade when pressed.

Tetanus

Bacterial intoxication by Clostridium tetani where tetanospasmin toxin blocks the relaxation pathway, causing rigid muscle spasms and lockjaw.

Botulism

Condition caused by Clostridium botulinum neurotoxin which blocks the release of acetylcholine, leading to flaccid paralysis.

Leprosy (Hansen's Disease)

Bacterial infection by Mycobacterium leprae that targets peripheral nerves and skin cells and grows best at $30^{\circ}\text{C}$.

Poliomyelitis (Polio)

A viral CNS infection that invades the anterior horn motor neurons, leading to asymmetrical paralysis in less than 1% of cases.

Rabies

A neurotropic viral infection transmitted via animal bites that travels up peripheral nerves to the brain, causing fatal encephalitis and hydrophobia.

African Sleeping Sickness

A vector-borne protozoan infection caused by Trypanosoma brucei and transmitted by the Tsetse fly, resulting in terminal coma.

Spongiform Encephalopathies

Fatal neurological pathologies caused by prions ($PrP^{Sc}$ infectious proteins) that create microscopic holes in brain tissue.