Hepatitis D Virus
Classification General Characteristics Structure Features Epidemiology Pathogenesis Transmission Transmission of hepatitis D is similar to that of hepatitis B. Host risk factors Pathophysiology Clinical Presentation General Coinfection Superinfection Diagnosis and Management Diagnosis Table: Hepatitis D infection Serum markers Acute HBV/HDV coinfection Acute HDV superinfection Chronic HDV infection HBsAg Positive Positive Positive Anti-HBc IgM Positive Negative […]
Hepatitis A Virus
Classification General Characteristics Structure Basic features Epidemiology Pathogenesis Transmission Risk factors Pathophysiology Clinical Presentation General features Specific symptoms The presence of 1 of the following symptoms is a reason to suspect hepatitis A infection, especially in the presence of risk factors: Diagnosis and Management Diagnosis Management Prevention Comparison of Hepatitis Viruses Differential Diagnosis References
Rhinovirus
Classification General Characteristics Structure Picornavirus family RNA virus Positive-sense ssRNA Naked Basic features Very small: 30 nm Acid-labile → inactivated by gastric acid Temperature for proliferation: 33–35°C (found in the nose) > 100 serotypes can cause upper respiratory infections (the common cold). Capable of surviving on hands for hours Associated diseases Upper respiratory tract infections […]
Mycology
Growth Forms and Reproduction Growth forms Multicellular forms include molds and mushrooms: Mostly composed of thread-like hyphae: Septated: Cell walls subdivide the hyphae. Coenocytic: Hyphae lack cell walls. Familiar “mushrooms” are reproductive organs (thallus) of fungi. Tubular network systems in which hyphae form branching nets (mycelium) Unicellular forms include yeasts: Yeasts do not have hyphae […]
Epidemic Typhus
Overview Definition Epidemic typhus is a potentially lethal, febrile illness caused by the obligate intracellular gram-negative bacterium, Rickettsia prowazekii. Epidemiology Transmission: Typhus is transmitted by infected lice. Infections occur in winter or spring. Risk factors: Overcrowded conditions: Reported in army camps, refugee camps, prisons, and homeless shelters Sometimes called “jail fever” Poor hygiene: Civil strife […]
Hepatitis E Virus
Classification General Characteristics Structure Basic features Epidemiology Pathogenesis Transmission Host risk factors Pathophysiology Primary replication: Clinical Presentation Diagnosis and Management Diagnosis Management Prevention Comparison of Hepatitis Viruses Table: Comparison of hepatitis viruses A–E Differential Diagnosis References
Paracoccidioides/Paracoccidioidomycosis
General Characteristics of Paracoccidioides Features Morphology: Thermally dimorphic fungus Mold forms at 22°C–26°C Yeast forms at 37°C Mold form: thin, septated hyphae Yeast form: Oval/round budding yeast “Pilot’s wheel” or “Captain’s wheel” appearance: large cell surrounded by budding cells Clinically relevant species P. brasiliensis P. lutzii Forms of disease Asymptomatic lung infection Acute/subacute Chronic Epidemiology […]
Histoplasma/Histoplasmosis
General Characteristics of Histoplasma Features Morphology: thermally dimorphic fungus Ambient (low) temperature: mold form Body (high) temperature: yeast form Characteristics: Obligate aerobe Mold form: Septate mycelium: thin and branching Produce microconidia and tuberculate macroconidia Yeast form: Reproduce by budding Slightly oval 2–4 µm in diameter Found exclusively in macrophages Clinically relevant species H. capsulatum var. […]
Human Herpesvirus 8
Classification General Characteristics and Epidemiology General features of human herpesvirus 8 (HHV-8) Associated diseases Epidemiology Pathogenesis Reservoir Humans are the only known reservoir. Transmission It is not entirely clear how the virus is transmitted. Host risk factors Human herpesvirus 8 infection is usually asymptomatic. Clinical manifestations can occur in immunocompromised patients: Viral replication cycle Pathophysiology […]
Human Herpesvirus 6 and 7
Classification General Characteristics and Epidemiology Basic features of HHV-6 and HHV-7 Associated diseases The clinical relevance of HHV-6A is not entirely known. Epidemiology Pathogenesis Reservoir Humans are the reservoir for HHV-6 and HHV-7. Transmission HHV-6 and HHV-7 are transmitted through contact with saliva. Pathophysiology Clinical Presentation Human herpesvirus-6 infections are usually mild and occur during […]