WEEK 4 – Long Exam 4 Review (Spirochetes, Miscellaneous Bacteria, Rickettsiae & Chlamydia, Mycology, Virology)

Vocabulary flashcards covering key organisms, diseases, diagnostics, treatments, and structural terms from Week 4 lecture notes on spirochetes, miscellaneous bacteria, Rickettsiae & Chlamydia, mycology, and virology.

Axial filament (axial fibril)

Flagella-like structure wrapped around a spirochete; provides corkscrew motility.

Treponema pallidum subsp. pallidum

Spirochete that causes syphilis; microaerophilic, killed rapidly at 42 °C.

Hunterian (hard) chancre

Painless genital lesion characteristic of primary syphilis.

Secondary syphilis

Systemic stage with fever, sore throat, lymphadenopathy, and palm-sole rash.

Latent syphilis

Subclinical period diagnosed only serologically; occurs >1 year after infection.

Tertiary syphilis

Tissue-destructive phase with gummas, neurosyphilis, and cardiovascular lesions.

Congenital syphilis

Placental transmission of T. pallidum causing fetal death or neonatal disease.

Dark-field microscopy

Definitive microscopic method for observing motile spirochetes in lesions.

Nontreponemal test

Serology detecting reagin antibodies (e.g., RPR, VDRL) used to monitor therapy.

Treponemal test

Serology detecting antibodies to treponemal antigens (e.g., FTA-ABS, TPPA).

Yaws (frambesia tropica)

Chronic skin, bone, and cartilage disease caused by T. pallidum subsp. pertenue.

Azithromycin (yaws dose)

Single oral 30 mg/kg (max 2 g) treatment recommended by WHO for yaws.

Borrelia recurrentis

Louse-borne spirochete causing epidemic relapsing fever.

Pediculus humanus corporis

Body louse vector for Borrelia recurrentis.

Relapsing fever

Febrile illness with recurring episodes due to antigenic variation of Borrelia.

Borrelia burgdorferi

Hard-tick transmitted spirochete causing Lyme disease.

Erythema migrans

Bull’s-eye skin lesion pathognomonic for early Lyme disease.

Acrodermatitis chronica atrophicans

Chronic skin atrophy associated with late Lyme arthritis.

Barbour-Stoenner-Kelly medium

Special culture medium for Borrelia species.

Leptospira interrogans

Hook-ended spirochete causing leptospirosis; obligate aerobe.

Weil’s syndrome

Icteric leptospirosis with jaundice, renal failure, and hemorrhage.

Aseptic meningitis (leptospira)

Hallmark of immune stage in anicteric leptospirosis.

Fletcher’s medium

Enrichment medium for cultivating Leptospira from blood, CSF, or urine.

Campylobacter jejuni

Microaerophilic curved rod from poultry; leading cause of bacterial diarrhea.

Azithromycin (Campylobacter dose)

500 mg once daily × 3 days—preferred therapy for C. jejuni gastroenteritis.

Spirillum minus

Gram-negative helical rod causing rat-bite fever; commensal in rodents.

Streptobacillary rat-bite fever

Febrile illness with rash and migratory arthritis from S. minus exposure.

Bacillus anthracis

Gram-positive spore-forming rod; agent of anthrax.

Cutaneous anthrax

Form featuring painless black eschar at inoculation site.

Woolsorter’s disease

Inhalational (pulmonary) anthrax contracted from spore-contaminated wool.

Malachite green spore stain

Differential stain for B. anthracis endospores.

Listeria monocytogenes

Gram-positive motile rod causing listeriosis; tumbling motility at RT.

Maternal listeriosis

Third-trimester infection producing flu-like illness and possible fetal loss.

Ampicillin + gentamicin

Drug combination of choice for neonatal or CNS listeriosis.

Legionella pneumophila

Aquatic gram-negative coccobacillus; causes Legionnaires’ disease.

Buffered charcoal yeast extract (BCYE)

Selective medium containing L-cysteine for Legionella culture.

Pontiac fever

Self-limited flu-like illness caused by Legionella without pneumonia.

Mycoplasma pneumoniae

Cell wall-less bacterium causing primary atypical pneumonia ('walking pneumonia').

SP4 broth

Fastidious culture medium for Mycoplasma species.

Rickettsia rickettsii

Tick-borne agent of Rocky Mountain spotted fever (spotted fever group).

Rickettsia prowazekii

Louse-borne agent of epidemic typhus (typhus group).

Eschar (scrub typhus)

Black necrotic lesion at chigger bite in Orientia tsutsugamushi infection.

Doxycycline (scrub typhus)

First-line antibiotic until afebrile 48 h, minimum 7 days.

Chlamydia trachomatis

Obligate intracellular gram-negative bacterium causing trachoma and STIs.

Elementary body (EB)

Infectious, extracellular form of Chlamydia with rigid wall.

Reticulate body (RB)

Replicative, non-infectious intracellular form of Chlamydia.

Lymphogranuloma venereum (LGV)

Invasive STI by C. trachomatis L1-L3 with ulcer and lymphadenopathy.

Buffalo green monkey cell line

Preferred culture system for isolation of Chlamydia trachomatis.

Azithromycin 1 g single dose

First-line therapy for uncomplicated C. trachomatis infection.

Mycology

Study of fungi, their classification, morphology, and pathogenicity.

Chitin

N-acetylglucosamine polymer unique to fungal cell walls.

Ergosterol

Sterol in fungal cell membranes targeted by many antifungals.

Septate hyphae

Fungal filaments containing cross-walls (septa).

Dematiaceous

Pigmented (dark) fungal hyphae or spores.

Conidium

Asexual spore borne on conidiophores of molds.

Dimorphic fungus

Fungus existing as mold at 25 °C and yeast at 37 °C (e.g., Histoplasma).

Zygomycetes

Lower fungi with non-septate hyphae producing sporangiospores.

Ascospores

Sexual spores formed inside asci of Ascomycetes.

Basidiospores

Sexual spores borne on basidium of Basidiomycetes.

Fungi imperfecti (Deuteromycetes)

Group of medically important fungi with no known sexual stage.

Superficial mycosis

Fungal infection limited to outer keratinized layers of skin or hair.

Malassezia globosa

Lipophilic yeast causing tinea versicolor.

Azelaic acid (fungal)

Pigment-altering metabolite responsible for patches in tinea versicolor.

Hortaea werneckii

Halotolerant dimorphic fungus causing tinea nigra (dark palm lesions).

White piedra

Hair shaft infection with white nodules by Trichosporon beigelii.

Madura foot (mycetoma)

Subcutaneous granulomatous infection of foot by actinomycetes or fungi.

Chromoblastomycosis

Slowly progressive warty lesions with sclerotic bodies by dematiaceous fungi.

Rhinosporidium seeberi

Aquatic protist-like organism causing nasal polyps (rhinosporidiosis).

Histoplasma capsulatum

Dimorphic fungus causing pulmonary histoplasmosis; intracellular yeast.

Itraconazole

Azole antifungal used for histoplasmosis and chromoblastomycosis.

Candida albicans

Dimorphic yeast forming pseudohyphae; causes candidiasis.

Cryptococcus neoformans

Encapsulated yeast causing meningitis, especially in AIDS.

India ink preparation

Negative stain highlighting Cryptococcus capsule in CSF.

Virus

Submicroscopic obligate intracellular parasite with DNA or RNA genome.

Capsid

Protein shell protecting viral genome and providing symmetry.

Envelope (virus)

Lipid membrane with glycoproteins surrounding some viruses; fragile in dry environments.

Icosahedral symmetry

Twenty-sided capsid structure common in many viruses.

Adenoviridae

Non-enveloped dsDNA viruses causing pharyngitis, conjunctivitis, and pneumonia.

Dane particle

Complete enveloped virion of Hepatitis B virus.

Hepatitis B surface antigen (HBsAg)

Envelope protein used for diagnosis and vaccine target.

Herpesviridae

Large enveloped dsDNA viruses with lifelong latency in host cells.

Varicella-Zoster Virus (VZV)

Herpesvirus causing chickenpox and shingles; latent in dorsal root ganglia.

Epstein–Barr Virus (EBV)

Herpesvirus causing infectious mononucleosis and associated with Burkitt lymphoma.

Cytomegalovirus (CMV)

Herpesvirus causing congenital infections and disease in immunosuppressed.

Human herpesvirus 6

Agent of roseola infantum (exanthem subitum).

Human papillomavirus 16/18

High-risk HPV types linked to cervical and penile cancers.

Parvovirus B19

Small ssDNA virus causing erythema infectiosum and aplastic crises.

Poxviridae

Largest DNA viruses; include smallpox and molluscum contagiosum.

Coronavirus (SARS-CoV-2)

Enveloped ssRNA virus using ACE2 receptor; causes COVID-19.

TIM-1 receptor

Cell receptor exploited by Ebola virus for entry.

Flavivirus

Mosquito-borne RNA viruses such as dengue and West Nile.

Yellow fever

Hemorrhagic flavivirus infection preventable by live vaccine.

Hepatitis C virus

Blood-borne flavivirus leading to chronic hepatitis and liver cancer.

Orthomyxoviridae

Segmented RNA viruses causing influenza; types A, B, C.

Neuraminidase inhibitors

Oseltamivir & zanamivir; antivirals active against influenza A & B.

Paramyxovirus

Enveloped RNA viruses such as measles, mumps, and parainfluenza.

Syncytium formation

Cell fusion effect typical of paramyxoviruses and HSV.

Picornavirus

Small non-enveloped RNA viruses including poliovirus, HAV, rhinovirus.

Pleconaril

Investigational antiviral targeting picornavirus capsid.

Retrovirus

RNA virus family employing reverse transcriptase (e.g., HIV).