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,…
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…
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,…
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…
And he would play his Diphtheria Blues —Frank Zappa This chapter includes a variety of highly pathogenic Gram-positive rods that are not currently common causes of human disease. Their medical…
MUMPS VIROLOGY Mumps virus is a paramyxovirus, and only one major antigenic type is known. Like fellow members of its genus, it contains a single-stranded, negative-sense RNA genome, and a…
BRUCELLA BACTERIOLOGY Brucella species are small, coccobacillary, Gram-negative rods that morphologically resemble Haemophilus and Bordetella. They are nonmotile, non-acid-fast, and non-spore-forming. The cells have a typical Gram-negative structure, and the…
SUPERFICIAL FUNGI Dermatophytes Dermatophytoses are superficial infections of the skin and its appendages, commonly known as ringworm (Figure 45–1), athlete’s foot, and jock itch. They are caused by species of…
heart is like wax; it is melted in the midst of my bowels. —The Bible: Psalms 22:14 This group of curved Gram-negative rods includes Vibrio cholerae, the cause of cholera,…
PAPILLOMAVIRUSES VIROLOGY Papillomaviruses are small, naked capsid (unenveloped), double-stranded, circular DNA viruses exhibiting cubic (icosahedral) symmetry of 55 nm in diameter (Figure 19–1). The icosahedral capsid comprises two capsid (structural)…
