Mumps Virus/Mumps
Classification General Characteristics Structure Clinically relevant species Disease Epidemiology Epidemiology Transmission Pathogenesis and Clinical Presentation Pathophysiology Clinical presentation The incubation period is 2–3 weeks. After the incubation period, prodromal symptoms occur for 3–5 days, including: After the prodromal period, the patient may present asymptomatically (20% of cases) or develop symptoms depending on the affected organ: […]
Babesia/Babesiosis
General Characteristics of Babesia Basic features of Babesia Clinically relevant species Epidemiology and Risk Factors Epidemiology Risk factors For babesiosis: For severe disease: Pathogenesis Reservoirs Transmission Life cycle and pathophysiology Outside a human host: Inside a human host: Clinical Presentation Symptoms The incubation period for babesiosis is 1–4 weeks. Mild-to-moderate disease: Severe disease: Physical exam […]
Ehrlichiosis and Anaplasmosis
General Characteristics Basic features of Ehrlichia and Anaplasma Gram negative Obligate intracellular bacteria Coccobacilli Grow in membrane-bound vacuoles in leukocytes, particularly: Monocytes Granulocytes Light microscopy: Individual organisms are difficult to appreciate. Frequently visualized as morulae (microcolony of organisms within a vacuole) Stains: Wright Giemsa Clinically relevant species The most notable species are: Ehrlichia chaffeensis → […]
Mycobacterium
General Characteristics Basic features Morphology and properties: Staining properties: Classification Mycobacteria: Most important pathogenic species: Pathogenesis Reservoirs Transmission Virulence Host risk factors General mycobacterial pathophysiology M. tuberculosis complex Epidemiology Pathophysiology Clinical presentation Table: Manifestations of MTBC infection Primary TB Secondary TB Extrapulmonary (miliary) TB Presentation Within 2 years of infection in 5%–10% of cases Reactivation […]
Influenza Viruses/Influenza
Classification General Characteristics Structure and basic features The influenza virus is a member of the Orthomyxoviridae family. Clinically relevant species and diseases Influenza viruses cause a febrile respiratory disease known as influenza. There are 3 distinct clinically relevant species of the virus: Table: Characteristics and clinical manifestations of influenza viruses Characteristics Influenza A Influenza B […]
Bacteriology
Introduction Structure Table: Structures of the bacterial cell with their chemical composition and functions Structure Chemical composition Function Appendages Flagellum Protein Motility Pili/fimbriae Glycoprotein Adherence to cell surface Specialized structures Spore Keratin-like coat Dipicolinic acid Peptidoglycan DNA Gram+ only Resists dehydration, heat, and chemicals Cell envelope Capsule Organized polysaccharide layer Protects against phagocytosis Slime layer […]
Strongyloidiasis
Epidemiology and Etiology Epidemiology Worldwide prevalence: 100 million cases currently Most common in tropical and warm temperate regions, with ¾ of cases in Southeast Asia, Africa, and Western Pacific countries Etiology Strongyloidiasis is caused by a parasitic infection by the roundworm (nematode) Strongyloides stercoralis. Roundworms are nonsegmented worms that can infect the GI tract, blood, […]
Measles Virus
Classification General Characteristics Genus: Morbillivirus Family: Paramyxoviridae Single-stranded, linear, negative-sense RNA virus Enveloped virus Large helical capsid carries RNA-dependent RNA polymerase in virion. Epidemiology and Pathogenesis Epidemiology Incidence: 50–300/year in the United States Mainly a childhood disorder Since 2-dose measles, mumps, rubella (MMR) vaccination, US cases ↓ 99% Incidence: males = females Higher mortality observed […]
Streptococcus
General Characteristics Shared characteristics Capsule Biofilm Streptococci have the ability to form biofilms: Significance: Differentiation of Streptococcus Species Serologic (Lancefield) classification Hemolytic classification Streptococci grow well on blood agar. Streptococcus species are divided into 3 groups on the basis of their hemolysis pattern: Distinguishing factors of the pathogenic streptococci Distinguishing factors of the pathogenic streptococci […]
Parvovirus B19
Classification General Characteristics Structure Family Parvoviridae Genus Erythroparvovirus Nonenveloped, icosahedral capsid, and linear single-stranded DNA genome Very small: approximately 22–24 nm in diameter Basic features Discovered in 1974 Unable to propagate virus in cell cultures Unique tropism for human erythroid progenitor cells Epidemiology and Pathogenesis Epidemiology Infection occurs at all ages, but it is more […]