Reference cards, H to L

Haemophilus influenzae Bacterium · Small Gram-negative coccobacillus with X/V factors

Hantavirus Virus · Bunyavirus, deer mouse, pulmonary syndrome

Healthcare-associated infection Concept · Infection acquired in a care setting

Helicobacter pylori Bacterium · Curved urease-positive gastric rod

Hepatitis A virus Virus · Nonenveloped positive-sense RNA hepatitis virus

Hepatitis B virus Virus · Partially double-stranded DNA virus

Hepatitis C virus Virus · Enveloped positive-sense RNA virus

Hepatitis D virus Virus · Defective satellite virus needing HBV

Hepatitis E virus Virus · Waterborne enteric hepatitis, risk in pregnancy

Herd immunity Concept · Indirect protection at high population immunity

Herpes simplex virus Virus · Enveloped double-stranded DNA virus

Hippurate hydrolysis test Lab method · Purple color = GBS, C. jejuni, Listeria, Gardnerella

Histoplasma capsulatum Fungus · Dimorphic fungus with macrophage clue

HIV Virus · Retrovirus with reverse transcriptase

Hookworm (Ancylostoma/Necator) Parasite · Skin-penetrating cause of iron-deficiency anemia

Horizontal gene transfer Concept · Gene sharing between cells, not offspring

HTLV-1 Virus · Oncogenic retrovirus, ATLL and HAM/TSP

Human herpesvirus 6 Virus · Roseola infantum (sixth disease)

Human herpesvirus 8 Virus · Kaposi sarcoma-associated herpesvirus

Human metapneumovirus Virus · RSV-like bronchiolitis and pneumonia

Human papillomavirus Virus · Nonenveloped circular DNA virus

Immunofluorescence assay Lab method · Fluorophore-tagged antibody detection

Impetigo Disease · Superficial crusting skin infection of children

Incubation period Concept · Exposure-to-symptom-onset interval

India ink preparation Lab method · Negative stain that reveals a capsule halo

Indole test Lab method · Cherry-red ring = E. coli (indole positive)

Infectious mononucleosis Disease · EBV triad: fever, pharyngitis, lymphadenopathy

Infective endocarditis Disease · Infection of heart valves with vegetations

Influenza illness Disease · Abrupt seasonal respiratory illness

Influenza virus Virus · Segmented negative-sense RNA virus

Innate vs adaptive immunity Concept · Fast nonspecific defense vs slow specific memory

Isoniazid Antimicrobial · KatG-activated mycolic acid synthesis blocker

Japanese encephalitis virus Virus · Culex flavivirus, pigs and birds, Asia

JC virus Virus · Cause of PML in immunosuppression

Kingella kingae Bacterium · Fastidious HACEK coccobacillus of young children

Kirby-Bauer disk diffusion Lab method · Susceptibility testing concept

Klebsiella pneumoniae Bacterium · Encapsulated lactose-fermenting rod

KOH preparation Lab method · Alkali clears keratin to reveal fungal elements

Lac operon Concept · Model of inducible gene regulation

Lactobacillus species Bacterium · Doderlein vaginal-flora acid producer

Lactophenol cotton blue Lab method · Mounting stain for mold morphology

Lassa virus Virus · Arenavirus, Mastomys rat, West Africa

Lateral flow assay Lab method · Rapid immunochromatographic strip test

Legionella pneumophila Bacterium · Water-associated intracellular rod

Leishmania species Parasite · Sandfly-borne macrophage parasite

Leptospira interrogans Bacterium · Question-mark spirochete; rat-urine water exposure

Lincosamides (clindamycin) Antimicrobial · 50S peptidyl-transferase blocker, anaerobe-active

Lipoglycopeptides Antimicrobial · Lipid-tailed glycopeptides for Gram-positives

Lipopeptides (daptomycin) Antimicrobial · Calcium-dependent membrane depolarizer

Listeria monocytogenes Bacterium · Tumbling motility Gram-positive rod

Loa loa Parasite · African eye worm with Calabar swellings

Lyme disease Disease · Tick-borne multistage spirochetal illness

Lymphocytic choriomeningitis virus Virus · Arenavirus, house mouse, aseptic meningitis

Lysogenic vs lytic cycle Concept · Two paths a phage can take