Table of contents Section I Introduction Section II Basic Principles of Medical Microbiology Section III Basic Concepts in the Immune Response Section IV General Principles of Laboratory Diagnosis Section V Bacteriology Section VI Virology Section VII Mycology Section VIII Parasitology Section I Introduction to Medical Microbiology.htm? Section II Bacterial Classification, Structure, and Replication.htm? Bacterial Metabolism and Genetics.htm? Viral Classification, Structure, and Replication.htm? Fungal Classification, Structure, and Replication.htm? Parasitic Classification, Structure, and Replication.htm? Commensal and Pathogenic Microbial Flora in Humans.htm? Sterilization, Disinfection, and Antisepsis.htm? Section III 09 Elements of Host Protective Responses.htm? 10 Humoral Immune Responses.htm? 11 Cellular Immune Responses.htm? 12 Immune Responses to Infectious Agents.htm? 13 Antimicrobial Vaccines.htm? Section IV 14 Microscopic Principles and Applications.htm? 15 In Vitro Culture Principles and Applications.htm? 16 Molecular Diagnosis.htm? 17 Serologic Diagnosis.htm? Section V 18 Mechanisms of Bacterial Pathogenesis.htm? 19 Laboratory Diagnosis of Bacterial Diseases.htm? 20 Antibacterial Agents.htm? 21 Staphylococcus and Related Gram-Positive Cocci.htm? 22 Streptococcus.htm? 23 Enterococcus and Other Gram-Positive Cocci.htm? 24 Bacillus.htm? 25 Listeria and Erysipelothrix.htm? 26 Corynebacterium and Other Gram-Positive Rods.htm? 27 Nocardia and Related Bacteria.htm? 28 Mycobacterium.htm? 29 Neisseria and Related Bacteria.htm? 30 Enterobacteriaceae.htm? 31 Vibrio and Aeromonas.htm? 32 Campylobacter and Helicobacter.htm? 33 Pseudomonas and Related Bacteria.htm? 34 Haemophilus and Related Bacteria.htm? 35 Bordetella.htm? 36 Francisella and Brucella.htm? 37 Legionella.htm? 38 Miscellaneous Gram-Negative Rods.htm? 39 Clostridium.htm? 40 Anaerobic, Non-Spore-Forming, Gram-Positive Bacteria.htm? 41 Anaerobic Gram-Negative Bacteria.htm? 42 Treponema, Borrelia, and Leptospira.htm? 43 Mycoplasma and Ureaplasma.htm? 44 Rickettsia and Orientia.htm? 45 Ehrlichia, Anaplasma, and Coxiella.htm? 46 Chlamydia and Chlamydophila.htm? 47 Role of Bacteria in Disease.htm? Section VI 48 Mechanisms of Viral Pathogenesis.htm? 49 Antiviral Agents.htm? 50 Laboratory Diagnosis of Viral Diseases.htm? 51 Papillomaviruses and Polyomaviruses.htm? 52 Adenoviruses.htm? 53 Human Herpesviruses.htm? 54 Poxviruses.htm? 55 Parvoviruses.htm? 56 Picornaviruses.htm? 57 Coronaviruses and Noroviruses.htm? 58 Paramyxoviruses.htm? 59 Orthomyxoviruses.htm? 60 Rhabdoviruses, Filoviruses, and Bornaviruses.htm? 61 Reoviruses.htm? 62 Togaviruses and Flaviviruses.htm? 63 Bunyaviridae and Arenaviridae.htm? 64 Retroviruses.htm? 65 Hepatitis Viruses.htm? 66 Unconventional Slow Viruses Prions.htm? 67 Role of Viruses in Disease.htm? Section VII 68 Pathogenesis of Fungal Disease.htm? 69 Laboratory Diagnosis of Fungal Diseases.htm? 70 Antifungal Agents.htm? 71 Superficial and Cutaneous Mycoses.htm? 72 Subcutaneous Mycoses.htm? 73 Systemic Mycoses Due to Dimorphic Fungi.htm? 74 Opportunistic Mycoses.htm? 75 Fungal and Fungal-Like Infections of Unusual or Uncertain Etiology.htm? 76 Mycotoxins and Mycotoxicoses.htm? 77 Role of Fungi in Disease.htm? Section VIII 78 Pathogenesis of Parasitic Diseases.htm? 79 Laboratory Diagnosis of Parasitic Disease.htm? 80 Antiparasitic Agents.htm? 81 Intestinal and Urogenital Protozoa.htm? 82 Blood and Tissue Protozoa.htm? 83 Nematodes.htm? 84 Trematodes.htm? 85 Cestodes.htm? 86 Arthropods.htm? 87 Role of Parasites in Disease.htm? Share please!!! Viruses Viruses are the smallest infectious particles, ranging in diameter from 18 to 600 nanometers (most viruses are less than 200 nm and cannot be seen with a light microscope) Viruses typically contain either deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) but not both; however, some viral-like particles not contain any detectable nucleic acids (e.g., prions; see Chapter 66), while the recently discovered Mimivirus contains both RNA and DNA The viral nucleic acids and proteins required for replication and pathogenesis are enclosed in a protein coat with or without a lipid membrane coat Viruses are true parasites, requiring host cells for replication The cells they infect and the host response to the infection dictate the nature of the clinical manifestation More than 2000 species of viruses have been described, with approximately 650 infecting humans and animals Infection can lead either to rapid replication and destruction of the cell or to a long-term chronic relationship with possible integration of the viral genetic information into the host genome The factors that determine which of these takes place are only partially understood For example, infection with the human immunodeficiency virus, the etiologic agent of the acquired immunodeficiency syndrome (AIDS), can result in the latent infection of CD4 lymphocytes or the active replication and destruction of these immunologically important cells Likewise, infection can spread to other susceptible cells, such as the microglial cells of the brain, resulting in the neurologic manifestations of AIDS Thus the diseases caused by viruses can range from the common cold to gastroenteritis to fatal catastrophes such as rabies, Ebola, smallpox, or AIDS Printed from STUDENT CONSULT: Medical Microbiology 6E (on 21 September 2009) ? 2009 Elsevier Bacteria Bacteria are relatively simple in structure They are prokaryotic organisms-simple unicellular organisms with no nuclear membrane, mitochondria, Golgi bodies, or endoplasmic reticulum-that reproduce by asexual division The bacterial cell wall is complex, consisting of one of two basic forms: a gram-positive cell wall with a thick peptidoglycan layer, and a gram-negative cell wall with a thin peptidoglycan layer and an overlying outer membrane (additional information about this structure is presented in Chapter 2) Some bacteria lack this cell wall structure and compensate by surviving only inside host cells or in a hypertonic environment The size (1 to 20 ?m or larger), shape (spheres, rods, spirals), and spacial arrangement (single cells, chains, clusters) of the cells are used for the preliminary classification of bacteria, and the phenotypic and genotypic properties of the bacteria form the basis for the definitive classification The human body is inhabited by thousands of different bacterial species-some living transiently, others in a permanent parasitic relationship Likewise, the environment that surrounds us, including the air we breathe, water we drink, and food we eat, is populated with bacteria, many of which are relatively avirulent and some of which are capable of producing life-threatening disease Disease can result from the toxic effects of bacterial products (e.g., toxins) or when bacteria invade normally sterile body sites Printed from STUDENT CONSULT: Medical Microbiology 6E (on 21 September 2009) ? 2009 Elsevier Fungi In contrast to bacteria, the cellular structure of fungi is more complex These are eukaryotic organisms that contain a well-defined nucleus, mitochondria, Golgi bodies, and endoplasmic reticulum (see Chapter 5) Fungi can exist either in a unicellular form (yeast) that can replicate asexually or in a filamentous form (mold) that can replicate asexually and sexually Most fungi exist as either yeasts or molds; however, some fungi can assume either morphology These are known as dimorphic fungi and include such organisms as Histoplasma, Blastomyces, and Coccidioides Printed from STUDENT CONSULT: Medical Microbiology 6E (on 21 September 2009) ? 2009 Elsevier Parasites Parasites are the most complex microbes Although all parasites are classified as eukaryotic, some are unicellular and others are multicellular (see Chapter 6) They range in size from tiny protozoa as small as to ?m in diameter (the size of many bacteria) to tapeworms that can measure up to 10 meters in length and arthropods (bugs) Indeed, considering the size of some of these parasites, it is hard to imagine how these organisms came to be classified as microbes Their life cycles are equally complex, with some parasites establishing a permanent relationship with humans and others going through a series of developmental stages in a progression of animal hosts One of the difficulties confronting students is not only an understanding of the spectrum of diseases caused by parasites, but also an appreciation of the epidemiology of these infections, which is vital for developing a differential diagnosis and an approach to the control and prevention of parasitic infections Printed from STUDENT CONSULT: Medical Microbiology 6E (on 21 September 2009) ? 2009 Elsevier Microbial Disease One of the most important reasons for studying microbes is to understand the diseases they cause and the ways to control them Unfortunately, the relationship between many organisms and their diseases is not simple Specifically, most organisms not cause a single, well-defined disease, although there are certainly ones that (e.g., Treponema pallidum, syphilis; poliovirus, polio; Plasmodium species, malaria) Instead, it is more common for a particular organism to produce many manifestations of disease (e.g., Staphylococcus aureus-endocarditis, pneumonia, wound infections, food poisoning) or for many organisms to produce the same disease (e.g., meningitis caused by viruses, bacteria, fungi, and parasites) In addition, relatively few organisms can be classified as always pathogenic, although some belong in this category (e.g., rabies virus, Bacillus anthracis, Sporothrix schenckii, Plasmodium species) Instead, most organisms are able to establish disease only under well-defined circumstances (e.g., the introduction of an organism with a potential for causing disease into a normally sterile site such as the brain, lungs, and peritoneal cavity) Some diseases arise when a person is exposed to organisms from external sources These are known as exogenous infections, and examples include diseases caused by influenza virus, Clostridium tetani, Neisseria gonorrhoeae, Coccidioides immitis, and Entamoeba histolytica Most human diseases, however, are produced by organisms in the person's own microbial flora that spread to inappropriate body sites where disease can ensue (endogenous infections) The interaction between an organism and the human host is complex The interaction can result in transient colonization, a long-term symbiotic relationship, or disease The virulence of the organism, the site of exposure, and the host's ability to respond to the organism determine the outcome of this interaction Thus the manifestations of disease can range from mild symptoms to organ failure and death The role of microbial virulence and the host's immunologic response is discussed in depth in subsequent chapters page page The human body is remarkably adapted to controlling exposure to pathogenic microbes Physical barriers prevent invasion by the microbe; innate responses recognize molecular patterns on the microbial components and activate local defenses and specific adapted immune responses that target the microbe for elimination Unfortunately, the immune response is often too late or too slow To improve the human body's ability to prevent infection, the immune system can be augmented either through the passive transfer of antibodies present in immune globulin preparations or through active immunization with components of the microbes (antigens) Infections can also be controlled with a variety of chemotherapeutic agents Unfortunately, many microbes can alter their antigenic complexion (antigenic variation) or develop resistance to even the most potent antibiotics Thus the battle for control between microbe and host continues, with neither side yet able to claim victory (although the microbes have demonstrated remarkable ingenuity) There clearly is no "magic bullet" that has eradicated infectious diseases Printed from STUDENT CONSULT: Medical Microbiology 6E (on 20 September 2009) ? 2009 Elsevier Diagnostic Microbiology Although several species of lice (Anoplura) infest humans as blood-feeding parasites, only the body louse is important in medicine as the vector of the rickettsia of typhus and trench fevers and the vector of the spirochetes of relapsing fever (see Table 86-2) The body louse, Pediculus humanus, and the head louse, P humanus capitis, are elongated, wingless, flattened insects with three pairs of legs and mouthpieces adapted for piercing flesh and sucking blood (Figure 86-10) The pubic or crab louse, Phthirus pubis, has a short, crablike abdomen with clawed second and third legs (Figure 86-11) Epidemiology Figure 86-11 Crab louse (P pubis) (Courtesy Dr RV Southcott; from Peters W: A Colour Atlas of Arthropods in Clinical Medicine London, Wolfe, 1992.) Epidemics of head lice are reported frequently in the United States, particularly among school children The head lice inhabit the hairs of the head and are transmitted by physical contact or sharing of hair brushes or hats Crab lice survive on blood meals around the hairs of the pubic and perianal areas of the body They are transmitted frequently from one person to another by sexual contact and contaminated toilet seats or clothing Body lice are usually found on clothing Unlike head or crab lice, they move to the body for feeding and return to the clothing after obtaining a blood meal All of the lice inject salivary fluids into the body during the ingestion of blood, which causes varying degrees of sensitization in the human host Clinical Syndromes Intense itching is the usual characteristic of infestation by lice (pediculosis) The patient may have pruritic, red papules around the ears, face, neck, or shoulders Secondary infection and regional adenopathy may be present Diagnosis The diagnosis is made by demonstration of the lice or eggs from a patient complaining of pruritus Frequently the patient has noticed the insects, and the diagnosis may be made over the telephone The eggs, or nits, are white, round objects that may be found attached to the hair shafts (head and crab lice) or on clothing (body lice) Treatment, Prevention, and Control Gamma benzene hexachloride (lindane) lotion applied to the entire body and left on for 24 hours is an effective treatment for lice Shaving the hair of affected areas is a desirable adjunct Adult lice in clothing must be destroyed by the application of lindane or DDT powder or by boiling Lice may survive in the environment for up to weeks; thus items such as brushes, combs, and bedding must be treated with a pediculicide or by boiling The best strategy for primary prevention is education and practice of good hygiene habits Secondary prevention may be practiced by a policy of routine surveillance (e.g., scalp inspections) in schools, daycare centers, military camps, and other institutions Repellents may be necessary for people who run a high risk of exposure in crowded conditions Fleas Physiology and Structure Fleas (Siphonaptera) are small, wingless insects with laterally compressed bodies and long legs adapted for jumping (Figure 86-12) Their mouthparts are adapted for sucking or "siphoning" blood from the host Epidemiology page 907 page 908 Figure 86-12 Flea (From Peters W: A Colour Atlas of Arthropods in Clinical Medicine London, Wolfe, 1992.) Fleas are cosmopolitan in distribution Most species are adapted to a particular host; however, they can readily feed on humans, particularly when deprived of their preferred host Fleas are important as vectors of plague and murine typhus and as intermediate hosts for dog (Dipylidium caninum) and rodent (Hymenolepis species) tapeworms that occasionally infect humans In contrast to the majority of fleas that not invade the human integument, the chigoe flea, Tunga penetrans, may cause considerable damage by actively invading the skin The female chigoe flea burrows into the skin, often under the toenails or between the toes, where she sucks blood and lays her eggs The chigoe flea is found in tropical and subtropical regions of America, as well as in Africa and the Far East It is not known to transmit human pathogens Clinical Syndromes As with the bites of other bloodsucking arthropods, flea bites result in pruritic, erythematous lesions of varying severity, which depends on the intensity of the infestation and the sensitivity of the bitten person The irritation caused by the flea's saliva may produce physical findings that vary from small, red welts to a diffuse, red rash Secondary infection may be a complication Cutaneous invasion by the chigoe flea produces an erythematous papule that is painful and pruritic Infested tissue can become severely inflamed and ulcerated Secondary infection is common In severe cases, the infestation may be complicated by tetanus or by gas gangrene, resulting in amputation Diagnosis The diagnosis of flea infestation is inferred in a patient with annoying bites who is also a pet (dog or cat) owner Examination of the patient and pet usually reveals the characteristic insect Diagnosis of tungiasis is made by detecting the dark portion of the chigoe flea's abdomen as it protrudes from the skin surface in the center of an inflamed lesion Figure 86-13 Bedbug (C lectularius) (From Peters W: A Colour Atlas of Arthropods in Clinical Medicine London, Wolfe, 1992.) Treatment, Prevention, and Control Palliative treatment with antipruritics and antihistamines is indicated for most flea bites Surgical removal of the chigoe flea is indicated Commercially available insecticides may control fleas at the source Topically applied repellents can protect people against flea bites Flea collars or powders on pets are also effective preventive measures Bugs Physiology and Structure Figure 86-14 Triatomid bug (Courtesy Dr D Minter; from Peters W: A Colour Atlas of Arthropods in Clinical Medicine London, Wolfe, 1992.) page 908 page 909 Bugs refer specifically to two bloodsucking insects, the bedbug and the triatomid bug (Figures 86-13 and 86-14) Both bugs are characterized by a long proboscis that is folded ventrally under the body when not in use The bedbug (Cimex lectularius) is a reddish brown insect approximately to mm long It has short wing pads but cannot fly The triatomid, or "kissing" bug, has yellow or orange markings on the body and an elongated head Triatomid bugs have wings and are aerial Epidemiology Both bedbugs and triatomid bugs are nocturnal and feed indiscriminately on most mammals Bedbugs are cosmopolitan in distribution, whereas triatomid bugs are limited to the Americas Bedbugs hide during the day in cracks and crevices of wooden furniture, under loose wallpaper, in the tufts of mattresses, and in box springs Triatomid bugs live in the cracks and crevices of walls and in thatched roofs Bedbugs not play a role in the transmission of human disease; however, triatomid bugs are important vectors of Chagas' disease (see Table 86-2 and Chapter 82) Clinical Syndromes The bites of bedbugs and triatomid bugs produce lesions that range from small, red marks to hemorrhagic bullae Bedbugs tend to bite in linear fashion on the trunk and arms, whereas triatomid bugs bite with higher frequency on the face The classic periorbital edema secondary to a triatomid bite is known as Romaña's sign The intensity of reaction to a bite depends on the degree of sensitization of the patient In addition to causing local lesions, bedbugs may be associated with nervous disorders and sleeplessness in children and adults Diagnosis The pattern and location of bites suggests bedbugs or triatomid bugs The detection of tiny spots of blood on bedding or the dead insects themselves is frequently the first sign of bedbug infestation Treatment, Prevention, and Control Topical palliatives are appropriate for the relief of pruritus Antihistamines may be indicated if dermatitis is severe Control consists of proper hygiene and the environmental applications of insecticides Stinging Insects Physiology and Structure The order Hymenoptera comprises the bees, wasps, hornets, and ants The modified ovipositor of the female, the apparatus for egg laying, serves as a stinging organ and is used for defense or to capture prey for food Members of Hymenoptera are known for their complex social systems, castes, and elaborate hive or nest structures Epidemiology Of the hymenopterans, the bees, or Apidae, live in complex social organizations such as hives or in less structured underground nests Only honeybees and bumblebees are of concern to humans because of their ability to sting The Vespidae include wasps, hornets, and yellow jackets; all are aggressive insects and a major cause of stings in humans In the act of stinging, the aroused insect inserts the sheath to open the wound The thrust of the stylets and injection of venom immediately follow One group of ants of concern in the United States is the fire ant, Solenopsis invicta Fire ants are particularly common in the southeastern states They are well camouflaged in large, hard-crusted mounds and attack when disturbed They bite their victim with strong mandibles and then sting repeatedly Clinical Syndromes An estimated 50 to 100 people die each year in the United States from reactions to stings of the hymenopterans Severe toxic reactions such as fever and muscle cramps can be caused by as few as 10 stings Allergic reactions are the most serious consequence, but others include pain, edema, pruritus, and a heat sensation at the site of the sting Anaphylactic shock from bee stings has resulted in death in some instances Treatment, Prevention, and Control No satisfactory treatment has been discovered for stings If left in the wound, the sting apparatus should be removed immediately The injection of epinephrine is sometimes necessary to counteract anaphylaxis (Emergency kits are available by prescription for sensitive people.) For the relief of local discomfort, calamine lotion or a topical corticosteroid cream for more severe local lesions is helpful Although there are no effective repellents against these insects, their nests can be destroyed with any of several commercially available insecticidal compounds General avoidance of areas inhabited by hymenopterans is advised for sensitive people Case Study and Questions A 4-year-old child was brought in by her mother with a complaint of itchy hands The child stayed at a daycare center during the day while her mother worked The girl had intense itching and a rash on her hands and arms for about weeks The itching became more severe and interfered with the child's sleep On physical examination, the child appeared well nourished and cared for The skin on her hands, wrists, and forearms appeared red and excoriated Raised, serpiginous "tracks" were noted on the sides of her fingers, on the ventral aspects of her wrists, and in the popliteal folds Several of the tracks were inflamed and were beginning to form pustules The mother stated that several other children at the daycare center were experiencing a similar problem What was the likely diagnosis? How would this diagnosis have been confirmed? How would this child have been treated and what advice would have been given to the mother regarding prevention? Did this child require antibiotic therapy? If so, why? What should have been done regarding the other children at the daycare center? page 909 page 910 Bibliography Binford CH, Connor DH: Pathology of Tropical and Extraordinary Diseases, vol Washington, DC, Armed Forces Institute of Pathology, 1976 Hwang SW, et al: Bed bug infestations in an urban environment Emerg Infect Dis 11:533-537, 2005 Markell EK, John DT, Krotoski WA: Markell and Voges' Medical Parasitology, 8th ed Philadelphia, WB Saunders, 1999 Najarian HH: Textbook of Medical Parasitology Baltimore, Williams & Wilkins, 1967 Peters W: A Colour Atlas of Arthropods in Clinical Medicine London, Wolfe, 1992 Swanson DL, Vetter RS: Bites of brown recluse spiders and suspected necrotic arachnidism N Engl J Med 352:700-707, 2005 Telford SR III: Arthropods of medical importance In Murray PR, et al (eds): Manual of Clinical Microbiology, 9th ed Washington, DC, ASM Press, 2007 Strickland GT: Hunter's Tropical Medicine and Emerging Infectious Diseases, 8th ed Philadelphia, WB Saunders, 2000 Van Horn KG, et al: Copepods associated with a perirectal abscess and copepod pseudo-outbreaks in stools for ova and parasite examinations Diagn Microbiol Infect Dis 15:561-565, 1992 Printed from STUDENT CONSULT: Medical Microbiology 6E (on 20 September 2009) © 2009 Elsevier 87 Role of Parasites in Disease A summary of the parasites (protozoan and helminths) most commonly associated with human disease is presented in this chapter Although many parasites are associated with a single organ system (e.g., gastrointestinal tract) and therefore cause a disease process involving that system, some of the most dramatic manifestations of parasitic disease occur when the parasite leaves its "normal" location in the human body Likewise, several different parasites may produce a similar disease syndrome The management of a specific parasitic infection may differ tremendously depending on the etiologic agent, and many antiparasitic treatment regimens are quite toxic So to guide both diagnostic and therapeutic efforts, it is useful to generate a differential diagnosis that includes the most likely parasites The development and prognosis of a parasitic infection often depend on factors aside from the innate virulence of the organism In determining the possibility of a parasitic infection, the meaning of any microbiologic data, and the necessity to treat and with what agent, one must take into account numerous factors, such as exposure history (e.g., travel to an endemic area), the potential infectious dose and/or organism burden, the use of prophylaxis (e.g., antimalarial prophylaxis), and the immunologic status of the host The presentation of a given parasitic infection may be quite different in a nonimmune traveler to an endemic region versus a semi-immune resident of the same region Likewise, the treatment and prevention strategies will be different as well Table 87-1 Summary of Parasites Associated with Human Disease System Affected and Disease Pathogens Blood Malaria Plasmodium spp Babesiosis Babesia spp Filariasis Wuchereria bancrofti, Brugia malayi, Mansonella spp., Loa loa Bone Marrow Leishmaniasis Leishmania donovani, Leishmania tropica Central Nervous System Meningoencephalitis Naegleria fowleri, Trypanosoma brucei gambiense, T b rhodesiense, T cruzi, Toxoplasma gondii, Microsporidia Granulomatous encephalitis Acanthamoeba spp., Balamuthia mandrillaris Mass lesion Brain abscess T gondii, Taenia solium, Schistosoma japonicum, Acanthamoeba spp., B mandrillaris Eosinophilic meningitis Cerebral malaria Angiostrongylus cantonensis, Toxocara spp Baylisascaris (neural larva migrans), Plasmodium falciparum Cerebral paragonimiasis Paragonimus westermani Eye Keratitis Acanthamoeba spp., Microsporidia (Nosema sp., Microsporidium spp., Encephalitozoon hellem), Onchocerca volvulus Chorioretinitis Conjunctivitis T gondii, O volvulus, L loa Ocular cysticercosis (mass lesion) T solium Toxocariasis Toxocara spp (ocular larva migrans; mimics retinoblastoma) Intestinal Tract Anal pruritus Enterobius vermicularis Colitis Entamoeba histolytica, Balantidium coli Diarrhea/dysentery E histolytica, Giardia lamblia (duodenalis), Microsporidia, Cryptosporidium parvum, Cyclospora cayetanensis, Isospora belli, Schistosoma mansoni, Strongyloides stercoralis, Trichuris trichiura Toxic megacolon Trypanosoma cruzi Obstruction Perforation Ascaris lumbricoides, Fasciolopsis buski Rectal prolapse Trichuris trichiura Liver, Spleen Abscess E histolytica, Fasciola hepatica Hepatitis Microsporidia (Encephalitozoon cuniculi, Nosema connori), T gondii Biliary obstruction A lumbricoides, F hepatica, Opisthorchis (Clonorchis) sinensis Cirrhosis/hepatosplenomegaly L donovani, L tropica, Toxocara canis and T cati (visceral larva migrans), Schistosoma mansoni, S japonicum Mass lesions T solium, Echinococcus granulosus, E multilocularis Genitourinary Vaginitis/urethritis Trichomonas vaginalis, E vermicularis Renal failure Plasmodium spp., L donovani Cystitis/hematuria Schistosoma haematobium, P falciparum (blackwater fever) Heart Myocarditis Microsporidia, T gondii, T cruzi Megacardia/complete heart block T cruzi Lung Abscess E histolytica, P Paragonimus westermani Nodule/mass Dirofilaria immitis, E granulosus, E multilocularis Pneumonitis A lumbricoides, S stercoralis, Toxocara spp., P westermani, T gondii, Ancylostoma braziliense Lymphatics Lymphedema W bancrofti, B malayi, other filaria Lymphadenopathy T gondii, trypanosomes Muscle Generalized myositis Trichinella spiralis, Microsporidia, Sarcocystis lindemanni, Toxocara spp Myocarditis T spiralis, T cruzi, Microsporidia, Toxocara spp Skin and Subcutaneous Tissue Ulcerative lesion Leishmania spp., Dracunculus medinensis Nodule/swellings O volvulus, L loa, T cruzi, Acanthamoeba spp., Toxocara spp Rash/vesicles T gondii, A braziliense, other migrating worms, schistosomes (cercarial dermatitis) Systemic General dissemination and multiple organ dysfunction Microsporidia, P falciparum, T gondii, L donovani, T cruzi, Toxocara spp., S stercoralis, T spiralis Iron deficiency, anemia Hookworms (Ancylostoma duodenale, Necator americanus) Megaloblastic anemia (Vitamin B12 deficiency) Diphyllobothrium latum This chapter provides a very broad listing of the various parasitic agents commonly associated with infections at specific body sites and/or specific clinical manifestations (Table 87-1) This information is meant to be used in conjunction with Table 79-1 as an aid in establishing a differential diagnosis and selecting the most likely clinical specimens that will help establish a specific etiologic diagnosis Other factors that may be important in determining the relative frequency with which specific parasites cause disease (e.g., travel and exposure history, specific clinical presentations) are covered in the individual chapters in this text or in the more comprehensive infectious disease texts cited in this and other chapters Bibliography Cohen J, Powderly WG: Infectious Diseases, 2nd ed St Louis, Mosby, 2004 Connor DH, et al: Pathology of Infectious Diseases Stamford, Conn, Appleton & Lange, 1997 Cook G, Zumala A: Manson's Tropical Diseases, 21st ed London, Elsevier Science, 2003 Garcia LS: Diagnostic Medical Parasitology, 4th ed Washington, DC, American Society for Microbiology, 2001 ... (e.g., Treponema pallidum, syphilis; poliovirus, polio; Plasmodium species, malaria) Instead, it is more common for a particular organism to produce many manifestations of disease (e.g., Staphylococcus... morphology These are known as dimorphic fungi and include such organisms as Histoplasma, Blastomyces, and Coccidioides Printed from STUDENT CONSULT: Medical Microbiology 6E (on 21 September 2009). .. transported across the cell membranes into the cytoplasm by active or passive transport mechanisms specific for the metabolite These mechanisms may use specific carrier or membrane transport proteins