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Histoplasmosisis caused by a mold that grows in soil rich in bird or bat droppings. Few exposed individuals become sick, but vulnerable individuals are susceptible. The yeast-like infectious cells grow inside phagocytes.
https://openstax.org/books/microbiology/pages/22-summary
Coccidioidomycosisis also acquired from soil and, in some individuals, will cause lesions on the face. Extreme cases may infect other organs, causing death.
https://openstax.org/books/microbiology/pages/22-summary
Blastomycosis, a rare disease caused by a soil fungus, typically produces a mild lung infection but can become disseminated in the immunocompromised. Systemic cases are fatal if untreated.
https://openstax.org/books/microbiology/pages/22-summary
Mucormycosisis a rare disease, caused by fungi of the order Mucorales. It primarily affects immunocompromised people. Infection involves growth of the hyphae into infected tissues and can lead to death in some cases.
https://openstax.org/books/microbiology/pages/22-summary
Aspergillosis, caused by the common soil fungusAspergillus, infects immunocompromised people. Hyphal balls may impede lung function and hyphal growth into tissues can cause damage. Disseminated forms can lead to death.
https://openstax.org/books/microbiology/pages/22-summary
Pneumocystispneumoniais caused by the fungusP. jirovecii. The disease is found in patients with AIDS and other immunocompromised individuals. Sulfa drug treatments have side effects, but untreated cases may be fatal.
https://openstax.org/books/microbiology/pages/22-summary
Cryptococcosisis caused byCryptococcus neoformans. Lung infections may move to the brain, causing meningitis, which can be fatal.
https://openstax.org/books/microbiology/pages/22-summary
The urinary system is responsible for filtering the blood, excreting wastes, and helping to regulate electrolyte and water balance.
https://openstax.org/books/microbiology/pages/23-summary
The urinary system includes thekidneys, ureters,urinary bladder, andurethra; the bladder and urethra are the most common sites of infection.
https://openstax.org/books/microbiology/pages/23-summary
Common sites of infection in the male reproductive system include the urethra, as well as the testes,prostateandepididymis.
https://openstax.org/books/microbiology/pages/23-summary
The most commons sites of infection in the female reproductive system are thevulva, vagina,cervix,andfallopian tubes.
https://openstax.org/books/microbiology/pages/23-summary
Infections of the urogenital tract can occur through colonization from the external environment, alterations in microbiota due to hormonal or other physiological and environmental changes, fecal contamination, and sexual transmission (STIs).
https://openstax.org/books/microbiology/pages/23-summary
Bacterialcystitisis commonly caused by fecal bacteria such asE. coli.
https://openstax.org/books/microbiology/pages/23-summary
Pyelonephritis is a serious kidney infection that is often caused by bacteria that travel from infections elsewhere in the urinary tract and may cause systemic complications.
https://openstax.org/books/microbiology/pages/23-summary
Leptospirosisis a bacterial infection of the kidney that can be transmitted by exposure to infected animal urine, especially in contaminated water. It is more common in tropical than in temperate climates.
https://openstax.org/books/microbiology/pages/23-summary
Nongonococcal urethritis (NGU)is commonly caused byC. trachomatis, M. genitalium, Ureaplasma urealyticum,andM. hominis.
https://openstax.org/books/microbiology/pages/23-summary
Diagnosis and treatment for bacterial urinary tract infections varies. Urinalysis (e.g., for leukocyte esterase levels, nitrite levels, microscopic evaluation, and culture of urine) is an important component in most cases. Broad-spectrum antibiotics are typically used.
https://openstax.org/books/microbiology/pages/23-summary
Bacterial vaginosisis caused by an imbalance in the vaginal microbiota, with a decrease in lactobacilli and an increase in vaginal pH.G. vaginalisis the most common cause of bacterial vaginosis, which is associated with vaginal discharge, odor, burning, and itching.
https://openstax.org/books/microbiology/pages/23-summary
Gonorrheais caused byN. gonorrhoeae, which can cause infection of the reproductive and urinary tracts and is associated with symptoms of urethritis. If left untreated, it can progress to epididymitis, salpingitis, and pelvic inflammatory disease and enter the bloodstream to infect other sites in the body.
https://openstax.org/books/microbiology/pages/23-summary
Chlamydiais the most commonly reported STI and is caused byC. trachomatis. Most infections are asymptomatic, and infections that are not treated can spread to involve the epididymis of memalesn and cause salpingitis and pelvic inflammatory disease in females.
https://openstax.org/books/microbiology/pages/23-summary
Syphilisis caused byT. pallidumand has three stages, primary, secondary, and tertiary. Primary syphilis is associated with a painless hard chancre lesion on genitalia. Secondary syphilis is associated with skin and mucous membrane lesions. Tertiary syphilis is the most serious and life-threatening, and can involve seri...
https://openstax.org/books/microbiology/pages/23-summary
Chancroidis an infection of the reproductive tract caused byH. ducreyithat results in the development of characteristicsoft chancres.
https://openstax.org/books/microbiology/pages/23-summary
Genital herpesis usually caused byHSV-2(although HSV-1 can also be responsible) and may cause the development of infectious, potentially recurrent vesicles
https://openstax.org/books/microbiology/pages/23-summary
Neonatal herpescan occur in babies born to infected people and can cause symptoms that range from relatively mild (more common) to severe.
https://openstax.org/books/microbiology/pages/23-summary
Human papillomavirusesare the most common sexually transmitted viruses and include strains that causegenital wartsas well as strains that causecervical cancer.
https://openstax.org/books/microbiology/pages/23-summary
Candidaspp. are typically present in the normal microbiota in the body, including the skin, respiratory tract, gastrointestinal tract, and female urogenital system.
https://openstax.org/books/microbiology/pages/23-summary
Disruptions in the normal vaginal microbiota can lead to an overgrowth ofCandida, causing vaginalcandidiasis.
https://openstax.org/books/microbiology/pages/23-summary
Vaginal candidiasis can be treated with topical or oral fungicides. Prevention is difficult.
https://openstax.org/books/microbiology/pages/23-summary
Trichomoniasisis a common STI caused byTrichomonas vaginalis.
https://openstax.org/books/microbiology/pages/23-summary
T. vaginalisis common at low levels in the normal microbiota.
https://openstax.org/books/microbiology/pages/23-summary
Trichomoniasis is often asymptomatic. When symptoms develop, trichomoniasis causes urinary discomfort, irritation, itching, burning, discharge from the penis, and vaginal discharge.
https://openstax.org/books/microbiology/pages/23-summary
Trichomoniasis is treated with the antiflagellate drugs tinidazole and metronidazole.
https://openstax.org/books/microbiology/pages/23-summary
The digestive tract, consisting of the oral cavity, pharynx, esophagus, stomach, small intestine, and large intestine, has a normal microbiota that is important for health.
https://openstax.org/books/microbiology/pages/24-summary
The constant movement of materials through the gastrointestinal canal, the protective layer of mucus, the normal microbiota, and the harsh chemical environment in the stomach and small intestine help to prevent colonization by pathogens.
https://openstax.org/books/microbiology/pages/24-summary
Infections or microbial toxins in the oral cavity can causetooth decay,periodontal disease, and various types ofulcers.
https://openstax.org/books/microbiology/pages/24-summary
Infections and intoxications of the gastrointestinal tract can cause general symptoms such as nausea, vomiting, diarrhea, and fever. Localized inflammation of the GI tract can result ingastritis,enteritis,gastroenteritis,hepatitis, orcolitis, and damage to epithelial cells of the colon can lead todysentery.
https://openstax.org/books/microbiology/pages/24-summary
Foodborne illnessrefers to infections or intoxications that originate with pathogens or toxins ingested in contaminated food or water.
https://openstax.org/books/microbiology/pages/24-summary
Dental caries,tartar, andgingivitisare caused by overgrowth of oral bacteria, usuallyStreptococcusandActinomycesspecies, as a result of insufficient dental hygiene.
https://openstax.org/books/microbiology/pages/24-summary
Gingivitis can worsen, allowingPorphyromonas,Streptococcus, andActinomycesspecies to spread and causeperiodontitis. WhenPrevotella intermedia,Fusobacteriumspecies, andTreponema vicentiiare involved, it can lead toacute necrotizing ulcerative gingivitis.
https://openstax.org/books/microbiology/pages/24-summary
The herpes simplex virus type 1 can cause lesions of the mouth and throat calledherpetic gingivostomatitis.
https://openstax.org/books/microbiology/pages/24-summary
Other infections of the mouth includeoral thrush, a fungal infection caused by overgrowth ofCandidayeast, andmumps, a viral infection of the salivary glands caused by the mumps virus, a paramyxovirus.
https://openstax.org/books/microbiology/pages/24-summary
Major causes of gastrointestinal illness includeSalmonellaspp.,Staphylococcusspp.,Helicobacter pylori,Clostridium perfringens,Clostridioides difficile,Bacillus cereus, andYersiniabacteria.
https://openstax.org/books/microbiology/pages/24-summary
C. difficileis an important cause of hospital acquired infection.
https://openstax.org/books/microbiology/pages/24-summary
Vibrio choleraecausescholera, which can be a severe diarrheal illness.
https://openstax.org/books/microbiology/pages/24-summary
Different strains ofE. coli, includingETEC,EPEC,EIEC, andEHEC, cause different illnesses with varying degrees of severity.
https://openstax.org/books/microbiology/pages/24-summary
H. pyloriis associated withpeptic ulcers.
https://openstax.org/books/microbiology/pages/24-summary
Salmonella entericaserotypes can causetyphoid fever, a more severe illness thansalmonellosis.
https://openstax.org/books/microbiology/pages/24-summary
Rehydration and other supportive therapies are often used as general treatments.
https://openstax.org/books/microbiology/pages/24-summary
Careful antibiotic use is required to reduce the risk of causingC. difficileinfections and when treating antibiotic-resistant infections.
https://openstax.org/books/microbiology/pages/24-summary
Common viral causes of gastroenteritis include rotaviruses, noroviruses, and astroviruses.
https://openstax.org/books/microbiology/pages/24-summary
Hepatitis may be caused by several unrelated viruses: hepatitis viruses A, B, C, D, and E.
https://openstax.org/books/microbiology/pages/24-summary
The hepatitis viruses differ in their modes of transmission, treatment, and potential for chronic infection.
https://openstax.org/books/microbiology/pages/24-summary
Giardiasis,cryptosporidiosis,amoebiasis, andcyclosporiasisare intestinal infections caused by protozoans.
https://openstax.org/books/microbiology/pages/24-summary
Protozoan intestinal infections are commonly transmitted through contaminated food and water.
https://openstax.org/books/microbiology/pages/24-summary
Treatment varies depending on the causative agent, so proper diagnosis is important.
https://openstax.org/books/microbiology/pages/24-summary
Microscopic examination of stool or biopsy specimens is often used in diagnosis, in combination with other approaches.
https://openstax.org/books/microbiology/pages/24-summary
Helminths often cause intestinal infections after transmission to humans through exposure to contaminated soil, water, or food. Signs and symptoms are often mild, but severe complications may develop in some cases.
https://openstax.org/books/microbiology/pages/24-summary
Ascaris lumbricoideseggs are transmitted through contaminated food or water and hatch in the intestine. Juvenile larvae travel to the lungs and then to the pharynx, where they are swallowed and returned to the intestines to mature. These nematode roundworms causeascariasis.
https://openstax.org/books/microbiology/pages/24-summary
Necator americanusandAncylostoma doudenalecausehookworm infectionwhen larvae penetrate the skin from soil contaminated by dog or cat feces. They travel to the lungs and are then swallowed to mature in the intestines.
https://openstax.org/books/microbiology/pages/24-summary
Strongyloides stercoralisare transmitted from soil through the skin to the lungs and then to the intestine where they causestrongyloidiasis.
https://openstax.org/books/microbiology/pages/24-summary
Enterobius vermicularisare nematode pinworms transmitted by the fecal-oral route. After ingestion, they travel to the colon where they causeenterobiasis.
https://openstax.org/books/microbiology/pages/24-summary
Trichuris trichiuracan be transmitted through soil or fecal contamination and causetrichuriasis. After ingestion, the eggs travel to the intestine where the larvae emerge and mature, attaching to the walls of the colon and cecum.
https://openstax.org/books/microbiology/pages/24-summary
Trichinellaspp. is transmitted through undercooked meat. Larvae in the meat emerge from cysts and mature in the large intestine. They can migrate to the muscles and form new cysts, causingtrichinosis.
https://openstax.org/books/microbiology/pages/24-summary
Taeniaspp. andDiphyllobothrium latumare tapeworms transmitted through undercooked food or the fecal-oral route.Taeniainfections causetaeniasis. Tapeworms use their scolex to attach to the intestinal wall. Larvae may also move to muscle or brain tissue.
https://openstax.org/books/microbiology/pages/24-summary
Echinococcus granulosusis a cestode transmitted through eggs in the feces of infected animals, especially dogs. After ingestion, eggs hatch in the small intestine, and the larvae invade the intestinal wall and travel through the circulatory system to form dangerous cysts in internal organs, causinghydatid disease.
https://openstax.org/books/microbiology/pages/24-summary
Flukes are transmitted through aquatic plants or fish.Liver flukescause disease by interfering with the bile duct.Intestinal flukesdevelop in the intestines, where they attach to the intestinal epithelium.
https://openstax.org/books/microbiology/pages/24-summary
Thecirculatory systemmoves blood throughout the body and has no normal microbiota.
https://openstax.org/books/microbiology/pages/25-summary
Thelymphatic systemmoves fluids from the interstitial spaces of tissues toward the circulatory system and filters the lymph. It also has no normal microbiota.
https://openstax.org/books/microbiology/pages/25-summary
The circulatory and lymphatic systems are home to many components of the host immune defenses.
https://openstax.org/books/microbiology/pages/25-summary
Infections of the circulatory system may occur after a break in the skin barrier or they may enter the bloodstream at the site of a localized infection. Pathogens or toxins in the bloodstream can spread rapidly throughout the body and can provoke systemic and sometimes fatal inflammatory responses such asSIRS,sepsis, a...
https://openstax.org/books/microbiology/pages/25-summary
Infections of the lymphatic system can causelymphangitisandlymphadenitis.
https://openstax.org/books/microbiology/pages/25-summary
Bacterial infections of the circulatory system are almost universally serious. Left untreated, most have high mortality rates.
https://openstax.org/books/microbiology/pages/25-summary
Bacterial pathogens usually require a breach in the immune defenses to colonize the circulatory system. Most often, this involves a wound or the bite of an arthropod vector, but it can also occur in hospital settings and result in nosocomial infections.
https://openstax.org/books/microbiology/pages/25-summary
Sepsisfrom both gram-negative and gram-positive bacteria, puerperal fever, rheumatic fever, endocarditis, gas gangrene, osteomyelitis,andtoxic shock syndromeare typically a result of injury or introduction of bacteria by medical or surgical intervention.
https://openstax.org/books/microbiology/pages/25-summary
Tularemia, brucellosis, cat-scratch fever, rat-bite fever,andbubonic plagueare zoonotic diseases transmitted by biological vectors
https://openstax.org/books/microbiology/pages/25-summary
Ehrlichiosis, anaplasmosis, endemicandmurine typhus, Rocky Mountain spotted fever, Lyme disease, relapsing fever,andtrench feverare transmitted by arthropod vectors.
https://openstax.org/books/microbiology/pages/25-summary
Because their symptoms are so similar to those of other diseases, many bacterial infections of the circulatory system are difficult to diagnose.
https://openstax.org/books/microbiology/pages/25-summary
Standard antibiotic therapies are effective for the treatment of most bacterial infections of the circulatory system, unless the bacterium is resistant, in which case synergistic treatment may be required.
https://openstax.org/books/microbiology/pages/25-summary
The systemic immune response to a bacteremia, which involves the release of excessive amounts of cytokines, can sometimes be more damaging to the host than the infection itself.
https://openstax.org/books/microbiology/pages/25-summary
Human herpesviruses suchEpstein-Barr virus(HHV-4) andcytomegalovirus(HHV-5) are widely distributed. The former is associated with infectious mononucleosis and Burkitt lymphoma, and the latter can cause serious congenital infections as well as serious disease in immunocompromised adults.
https://openstax.org/books/microbiology/pages/25-summary
Arboviral diseases such as yellow fever, dengue fever,andchikungunya feverare characterized by high fevers and vascular damage that can often be fatal.Ebola virus diseaseis a highly contagious and often fatal infection spread through contact with bodily fluids.
https://openstax.org/books/microbiology/pages/25-summary
Although there is a vaccine available for yellow fever, treatments for patients with yellow fever, dengue, chikungunya fever, and Ebola virus disease are limited to supportive therapies.
https://openstax.org/books/microbiology/pages/25-summary
Patients infected withhuman immunodeficiency virus (HIV)progress through three stages of disease, culminating inAIDS.Antiretroviral therapy (ART)uses various combinations of drugs to suppress viral loads, extending the period of latency and reducing the likelihood of transmission.
https://openstax.org/books/microbiology/pages/25-summary
Vector control and animal reservoir control remain the best defenses against most viruses that cause diseases of the circulatory system.
https://openstax.org/books/microbiology/pages/25-summary
Malariais a protozoan parasite that remains an important cause of death primarily in the tropics. Several species in the genusPlasmodiumare responsible for malaria and all are transmitted byAnophelesmosquitoes.Plasmodiuminfects and destroys human red blood cells, leading to organ damage, anemia, blood vessel necrosis, ...
https://openstax.org/books/microbiology/pages/25-summary
Toxoplasmosisis a widespread protozoal infection that can cause serious infections in the immunocompromised and in developing fetuses. Domestic cats are the definitive host.
https://openstax.org/books/microbiology/pages/25-summary
Babesiosis is a generally asymptomatic infection of red blood cells that can causes malaria-like symptoms in elderly, immunocompromised, or asplenic patients.
https://openstax.org/books/microbiology/pages/25-summary
Chagas diseaseis a tropical disease transmitted by triatomine bugs. The trypanosome infects heart, neural tissues, monocytes, and phagocytes, often remaining latent for many years before causing serious and sometimes fatal damage to the digestive system and heart.
https://openstax.org/books/microbiology/pages/25-summary
Leishmaniasisis caused by the protozoanLeishmaniaand is transmitted by sand flies. Symptoms are generally mild, but serious cases may cause organ damage, anemia, and loss of immune competence.
https://openstax.org/books/microbiology/pages/25-summary
Schistosomiasisis caused by a fluke transmitted by snails. The fluke moves throughout the body in the blood stream and chronically infects various tissues, leading to organ damage.
https://openstax.org/books/microbiology/pages/25-summary
The nervous system consists of two subsystems: thecentral nervous systemandperipheral nervous system.
https://openstax.org/books/microbiology/pages/26-summary
The skull and threemeninges(thedura mater,arachnoid mater, andpia mater) protect the brain.
https://openstax.org/books/microbiology/pages/26-summary
Tissues of the PNS and CNS are formed of cells calledglial cellsandneurons.
https://openstax.org/books/microbiology/pages/26-summary
Since theblood-brain barrierexcludes most microbes, there is no normal microbiota in the CNS.
https://openstax.org/books/microbiology/pages/26-summary
Some pathogens have specific virulence factors that allow them to breach the blood-brain barrier. Inflammation of the brain ormeningescaused by infection is calledencephalitisormeningitis, respectively. These conditions can lead to blindness, deafness, coma, and death.
https://openstax.org/books/microbiology/pages/26-summary
Bacterial meningitiscan be caused by several species of encapsulated bacteria, includingHaemophilus influenzae,Neisseria meningitidis,Streptococcus pneumoniae, andStreptococcus agalactiae(group B streptococci).H. influenzaeaffects primarily young children and neonates,N. meningitidisis the only communicable pathogen an...
https://openstax.org/books/microbiology/pages/26-summary
Symptoms of bacterial meningitis include fever, neck stiffness, headache, confusion, convulsions, coma, and death.
https://openstax.org/books/microbiology/pages/26-summary
Diagnosis of bacterial meningitis is made through observations and culture of organisms in CSF. Bacterial meningitis is treated with antibiotics.H. influenzaeandN. meningitidishave vaccines available.
https://openstax.org/books/microbiology/pages/26-summary
Clostridiumspecies cause neurological diseases, includingbotulismandtetanus, by producing potent neurotoxins that interfere with neurotransmitter release. The PNS is typically affected. Treatment ofClostridiuminfection is effective only through early diagnosis with administration of antibiotics to control the infection...
https://openstax.org/books/microbiology/pages/26-summary
Listeria monocytogenesis a foodborne pathogen that can infect the CNS, causing meningitis. The infection can be spread through the placenta to a fetus. Diagnosis is through culture of blood or CSF. Treatment is with antibiotics and there is no vaccine.
https://openstax.org/books/microbiology/pages/26-summary