4 Principles of Laboratory Diagnosis of Infectious Diseases
FIGURE 4–1. Specimens for the diagnosis of infection. A. Direct specimen. The pathogen is localized in an otherwise sterile site, and a barrier such as the skin must be passed…
MICROBIOLOGY
47 Cryptococcus, Histoplasma, Coccidioides, and Other Systemic Fungal Pathogens
CRYPTOCOCCUS CRYPTOCOCCUS NEOFORMANS and CRYPTOCOCCUS GATTII Cryptococcus is a genus of yeast 4 to 6 μm in diameter that produces a characteristic capsule (Figure 47–1), extending the overall diameter to…
13 Hepatitis Viruses
HEPATITIS A VIROLOGY Hepatitis A virus (HAV) belongs to the Picornaviridae (picornaviruses) family and Hepato-virus genus. It is an unenveloped (naked capsid), single-stranded, positive-sense RNA virus with a cubic (icosahedral)…
24 Staphylococci
FIGURE 24–1. Staphylococcus aureus. Gram stain showing the Gram-positive cocci in clusters resembling bunches of grapes (arrows) and neutrophils (arrowhead). (Image contributed by Professor Shirley Lowe, University of California, San…
18 Retroviruses: Human T-Lymphotropic Virus, Human Immunodeficiency Virus, and Acquired Immunodeficiency Syndrome
VIROLOGY STRUCTURE All retroviruses are remarkably similar in their basic composition and structure. The structure of HIV-1 is depicted in Figure 18–1. The virion size is about 100 nm in…
31 Haemophilus and Bordetella
FIGURE 31–1. Haemophilus influenzae Gram stain. The Gram-negative bacilli are small and so short that some appear almost round. This is the basis of the term coccobacilli. The morphology of…
9 Influenza, Parainfluenza, Respiratory Syncytial Virus, Adenovirus, and Other Respiratory Viruses
INFLUENZA VIRUS GROUP CHARACTERISTICS Influenza viruses are members of the orthomyxovirus group or family, which are enveloped, pleomorphic, single-stranded negative-sense segmented RNA viruses. They are classified into three major types,…
2 Immune Response to Infection
FIGURE 2–1. Human blood cells. Stem cells in the bone marrow divide to form two blood cell lineages: (1) the lymphoid stem cell gives rise to B cells that become…
46 Candida, Aspergillus, Pneumocystis, and Other Opportunistic Fungi
CANDIDA: GENERAL CHARACTERISTICS Candida species grow as typical 4 to 6 μm, budding, round, or oval yeast cells (Figure 46–1) under most conditions and at most temperatures. Under certain conditions,…
57 Trematodes
Two groups: Hermaphrodites and schistosomes For both groups, snails release motile cercariae in water Schistosoma cercariae in water infect humans through skin Of the many trematodes that infect humans, only…
