Babesia/Babesiosis (Clinical)
General Characteristics of Babesia Basic features of Babesia[1] Clinically relevant species[4‒6] Epidemiology and Risk Factors Epidemiology[4,5] Risk factors[4‒6] For babesiosis: For severe disease: Pathogenesis Reservoirs[4,6] Transmission[1,4,6] Life cycle and pathophysiology[1,4] Outside a human host: Inside a human host: Clinical Presentation Symptoms The incubation period for babesiosis is 1–4 weeks. Mild-to-moderate disease:[2,4‒6] Severe disease:[2,4‒6] Physical exam[2,5] […]
Scabies mite (Clinical)
General Characteristics of Scabies Basic features of scabies[1] Clinically relevant species[1,2] Sarcoptes scabiei (var. hominis) causes human scabies. Epidemiology[5,8] Pathogenesis Reservoir[1] Humans are the primary reservoir of S. scabiei. Transmission[1,2,5] Risk factors[1] Life cycle[1,2,6] Pathophysiology[6] The infection takes the form of: Clinical Presentation Key characteristic features[1–3,5,6] Classic scabies[1,3,5,6,8] Crusted scabies[1,5,6,8] Diagnosis Diagnosis is confirmed through […]
Rocky Mountain Spotted Fever (Clinical)
Overview Definition Rocky Mountain spotted fever (RMSF) is an infectious disease caused by the bacteria Rickettsia rickettsii, which is usually transmitted by ticks. Epidemiology[6,9,10] Etiology[2,6] Pathophysiology Clinical Presentation Symptoms usually occur within 2–14 days of exposure to an infected tick bite. Initial symptoms may be vague and non-specific (fever, generalized malaise). Patients may not be […]
Cryptosporidium/Cryptosporidiosis
General Characteristics of Cryptosporidium Epidemiology and Risk Factors Epidemiology Risk factors Pathophysiology Reservoirs Transmission Transmission is by the fecal–oral route. Ingestion of Cryptosporidium oocysts initiates infection. The different sources of transmission are: Life Cycle Infection is initiated by the ingestion of fully sporulated and environment-resistant oocysts. Pathogenesis Cryptosporidium causes secretory diarrhea associated with malabsorption. Clinical […]
Staphylococcus
Classification General Characteristics and Epidemiology Basic features of Staphylococcus Clinically relevant species The clinically relevant species can be classified based on the presence (or absence) of coagulase: Distinguishing features Table: Distinguishing features among the common pathogenic Staphylococcus species Species Coagulase Blood agar Mannitol salt agar Novobiocin*sensitivity S. aureus Positive Beta-hemolysis Yellow colonies Sensitive S. epidermidis […]
Candida/Candidiasis
General Characteristics Basic features of Candida Clinically relevant species The most clinically relevant Candida species include: Pathogenesis Reservoir Candida albicans is part of the normal human flora, particularly: Transmission Host risk factors Candidiasis is the most common opportunistic fungal infection. General risk factors for candidiasis: Additional risk factors for invasive disease: Virulence factors Pathophysiology Clinical […]
Hepatitis C Virus
Classification General Characteristics Structure Features Epidemiology Pathogenesis Transmission Humans are the only reservoir for the virus. Modes of transmission include: Host risk factors Pathophysiology Clinical Presentation Acute infection Chronic infection Diagnosis Viral markers Further testing Management Pharmacotherapy Prevention Hepatitis Viruses Comparative Table Differential Diagnosis References
Hepatitis B Virus
Classification General Characteristics Structure Features Epidemiology and Pathogenesis Epidemiology Transmission Host risk factors Pathophysiology Clinical Presentation Acute infection Chronic infection Diagnosis Viral markers Laboratory evaluation Screening for HBV infection: Acute hepatitis B: Past HBV infection (inactive): HBV-vaccinated individuals: Chronic hepatitis B: Table: Hepatitis B serologic panel HBsAg Anti-HBc-IgM Anti-HBc-IgG Anti-HBs Susceptible Negative Negative Negative Negative […]
Cystoisospora/Cystoisosporiasis and Cyclospora/Cyclosporiasis
General Characteristics Basic features of Cystoisospora and Cyclospora Protozoans: Single-celled Obligate intracellular parasites Taxonomy: Class: Conoidasida Subclass: Coccidia Clinically relevant species Both organisms cause intestinal disease in humans. Cystoisospora belli (formerly Isospora belli) causes cystoisosporiasis. Cyclospora cayetanensis causes cyclosporiasis. Epidemiology Cystoisospora: Occurs worldwide Predominantly seen in tropical and subtropical regions The least common of the […]
Microsporidia/Microsporidiosis
General Characteristics and Epidemiology Basic features of microsporidia Recently reclassified as a group of fungi (previously classified as protozoa) and includes approximately: 200 genera 1500 species Vary in: Spore size Nucleus arrangement Life cycle Obligate intracellular Unicellular Spore-forming Usually oval Resistant to degradation (survive for long months in the environment) Contain a unique organelle called […]