Fungal colonies are vegetative because they are composed of the cells involved in catabolism and growth.
"Cross-walls" inside the hyphae of most molds, which divide the hyphae into distinct, uninucleate cell-like units.
Hyphae (in a few classes of fungi) that contain no septa and appear as long, continuous cells with many nuclei.
Nonfilamentous, unicellular fungi that are typically spherical or oval; they are frequently found as a white powdery coating on fruits and leaves.
[In "budding"] the parent cell forms a protuberance (bud) on its outer surface; As the bud elongates, the parent cell's nucleus divides, and one nucleus migrates into the bud. Cell wall material is then laid down between the bud and parent cell, and the bud eventually breaks away.
Divide evenly to produce two new cells. During fission, the parent cell elongates, its nucleus divides, and two daughter cells are produced. [Increases in the number of yeast cells on a solid medium produce a colony similar to a bacterial colony.
Two forms of growth; Such fungi can grow either as a mold or as a yeast. Dimorphism in pathogenic fungi is temperature dependent: 37 deg. C = the fungus is yeastlike; 25 deg. C = it is mold-like.
Spores are formed from hyphae in a number of different ways, depending on the species. Both sexual and asexual reproduction in fungi occurs by the formation of spores. (Fungi are usually identified by spore type; Fungal spores can survive for extended periods in dry or hot environments. Fungal spores and bacterial endospores are different.)
Produced by an individual fungus through mitosis and subsequent cell division. Formed by the hyphae of one organism; When these spores germinate, they become organisms that are genetically identical to the parent.
Result from the fusion of nuclei from two opposite strains of the same species of fungus. A fungal sexual spore results form sexual reproduction, which consists of three phases: Plasmogamy, Karyogamy, and Meiosis. (Fungi produce sexual spores less frequently than asexual spores.)
Type of asexual spore; A unicellular or multicellular spore that is not enclosed in a sac. They are produced in a chain at the end of a Conidiophore.
Conidia formed by the fragmentation of a septate hypha into single, slightly thickened cells.
A thick-walled spore formed by rounding and enlargement within a hyphal segment. (i.e. - C. Albicans.)
Type of asexual spore formed within a sporangium, or sac, at the end of an aerial hypha called sporangiophore.
The diploid nucleus gives rise to haploid nuclei (sexual spores), some of which may be genetic recombinants.
A large spore enclosed in a thick wall. (This type of spore results from the fusion of the nuclei of two cells that are morphologically similar to each other.
Results from the fusion of the nuclei of two cells that can be either morphologically similar or dissimilar. These spores are produced in a sac-like structure called an ascus. These members of this phylum are called sac fungi because of the ascus.
(Club fungi; Possess septate hyphae; Include mushrooms.) Formed externally on the base pedestal called a Basidium. There are usually four basidiospores per basidium. Some of the basidiomycota produce asexual conidiospores.
They produce both asexual and sexual spores. Some ascomycetes have lost the ability to reproduce sexually.
Asexual fungi (ascomycetes) that have lost the ability to reproduce sexually, (i.e. - Penicillium.)
Any fungal infection [is called mycosis]. Mycoses are generally chronic (long-lasting) infections because fungi grow slowly. Mycoses are classified into five groups according to the degree of tissue involvement and mode of entry into the host: Systemic, Subcutaneous, Cutaneous, Superficial, or Opportunistic.
Fungal infections deep within the body. They are not restricted to any particular region of the body but can affect a number of tissues and organs. Systemic Mycoses are usually caused by fungi that live in the soil; Inhalation of spores is the route of transmission; these infections typically begin in the lungs and then spread to other body tissues. They are not contagious from animal to human or human to animal. Two systemic mycoses: Histoplasmosis & Coccidioidomycosis.
Fungal infections beneath the skin caused by saprophytic fungi that live in soil and on vegetation. Occurs by direct implantation of spores or mycelial fragments into a puncture found in the skin.
Fungi that infect only the epidermis, hair, & nails. Their infections are called dermatomycoses, or Subcutaneous Mycoses. Dermatophytes excrete keratinase, an enzyme that degrades keratin (a protein found in hair, skin, & nails. Infection is transmitted from human to human or from animal to human by direct contact. (i.e.- Barber shops have blue anti-bacterial where they soak their tools in order to prevent this kind of fungal infection.)
The fungi that cause this particular mycosis are localized along hair shafts and in superficial (surface) epidermal cells. These infections are prevalent in tropical climates.
Generally harmless in its normal habitat but can become pathogenic in a host who is seriously debilitated or traumatized, who is under treatment with broad-spectrum antibiotics, whose immune system is suppressed, or who has a lung disease. Pneumocystis is an opportunistic pathogen and is the most common life-threatening infection in AIDS patients.
a.k.a. Candidiasis; Frequently occurs in newborns, people with AIDS, and in people being treated with broad-spectrum antibiotics.
A combination of a green alga (or a cyanobacterium) and a fungus. Lichens are placed in the Kingdom Fungi and are classified according to the fungal partner, most often an ascomycete (the two exist in a mutualistic relationship-if the partners are separated, the lichen no longer exists). Lichens cans be grouped into three morphologic categories: Crustose Lichens (grow flush or encrusting onto the substratum), Foliose Lichens (more leaflike), and Fruticose Lichens (fingerlike projections).
The lichen's thallus, or body, forms when fungal hyphae grow around the algal cells to become the medulla.
Fungal hyphae also form a cortex, or protective covering, over the algal layer and sometimes under it as well.
A thickener used in many foods (i.e.- ice cream & cake decorations), is extracted from their cell walls. Algin is also used in the production of a wide variety of nonfood goods (i.e.- rubber tires and hand lotion).
Domoic Acid Intoxication
Domoic acid is a toxin, with symptoms ranging from diarrhea to memory loss. Diatoms are responsible for releasing this toxin. (Diatoms store energy captured through photosynthesis in the form of oil.)
Dinoflagellates are unicellular algae collectively called Plankton, or free-floating organisms. Their rigid structure is due to cellulose embedded on the plasma membrane.
Paralytic Shellfish Poisoning (PSP)
The toxin (saxitoxin) is concentrated when large numbers of dinoflagellates are eaten by mollusks, such as mussels or clams. Humans who eat these mollusks develop PSP.
A disease which occurs when the dinoflagellate Gambierdiscus Toxicus passes up the food chain and is concentrated in large fish. Ciguatera is endemic (constantly present) in the south Pacific Ocean and the Caribbean Sea.
Oomycote spores that have two flagella. They were previously classified with fungi (b/c they are superficially similar to fungi) however they are in fact "water molds." Oomycotes are decomposers that form cottony masses on dead algae and animals, usually in fresh water.
The feeding and growing stage of Protozoa. During this stage, Protozoa feed upon bacteria and small particulate nutrients.
Multiple fission; The nucleus undergoes multiple divisions before the cell divides. After many nuclei are formed, a small portion of cytoplasm concentrates around each nucleus, and then the single cell separates into daughter cells. (Protozoa reproduce asexually by fission, budding, or schizogony.)
During protozoan conjugation, two cells fuse, and a haploid nucleus from each cell migrates to the other cell.
Haploid sex cells produced by some protozoa. During reproduction, two gametes fuse to form a diploid zygote.
Permits the organism to survive when food, moisture, or oxygen are lacking, when temperatures are not suitable, or when toxic chemicals are present.
Where protozoans' excrete their waste. (The waste can also be eliminated through the plasma membrane.)
Highly modified flagellum on some protozoa; Consists of a membrane bordered by a flagellum.
Temporary extension of a cell's cytoplasm and plasma membrane; used by certain protozoans in movement and feeding.
Obligate intracellular parasites that are characterized by the presence of a complex of special organelles at the apexes (tips) of their cells; The organelles in these complexes contain enzymes that penetrate the host's tissue. They have a complex life cycle which involves transmission between several hosts (i.e.- Plasmodium).
The infective stage of Plasmodium; One of the minute active bodies into which sporozoans divide in one stage of their life cycle.
young plasmodium trophozoite that looks like a ring (the cytoplasm and nucleus are visible) in red blood cells.
Trophozoites of toxoplasma gondii which reproduce sexually and asexually in an infected cat.
Ciliates that have cilia similar to but shorter than flagella; The cilia are arranged in precise rows on the cell. They are moved in unison to propel the cell through its environment and to bring food particles to its mouth.
Photoautotrophs with a semirigid plasma membrane called a pellicle; Move by means of a flagellum at the anterior end; Also have a red eye spot at the anterior end which senses light and directs the cell.
Blood parasites transmitted by blood-feeding insects;Found in the circulatory system of the bitten host.
Fungal organisms which also contain amoebal characteristics; They live on soil, leaves, or decaying wood, and help to recycle organic matter.
Cellular Slime Molds
Typical eukaryotic cells that resemble amoebas; Remain disticint forms their entire life; When their food supply is exhausted they send out chemical signals to others, which soon aggregate into a large sluglike colony that functions as a single organism. It produces a fruiting body which produces spores; It scatters the spores, which can grow into another organism.
Plasmodial Slime Molds
Exist as a mass of protoplasm with many nuclei; The entire plasmodium moves as a giant amoeba; It engulfs organic debris and bacteria.
During cytoplasmic streaming, the protoplasm within the plasmodium moves and changes both its speed and direction so that the oxygen and nutrients are evenly distributed; It continues to grow as long as there is enough food and moisture for it to thrive.
Flatworms and Roundworms (Nematodes); Multicellular, eukaryotic animals that generally possess digestive, circulatory, nervous, excretory, and reproductive systems. Parasitic helminths must be specialized to live inside their hosts.
Helminths which have male reproductive organs in one individual and female reproductive organs in another individual.
Members of the Phylum Platyhelminthes; Dorsoventrally flattened; Classes of parasitic flatworms include trematodes and cestodes. They cause disease or developmental disturbances in a wide variety of animals.
a.k.a. trematodes; Have flat, leaf-shaped bodies with a ventral sucker and an oral sucker, which [together] help to hold the organism in place. They obtain food by absorbing it through their nonliving outer covering, called the cuticle.
a.k.a. cestodes. Intestinal parasites. Have suckers for attaching to the intestinal mucosa of the definitive host; Some species also have small hooks for attachment. They completely lack a digestive system, so in order to obtain nutrients from the small intestine, they absorb food through their cuticle.
Segments produced by the neck region of the scolex, as long as the scolex is attached and alive. Each mature proglottid contains both male and female reproductive organs. The proglottids farthest away from the scolex are the mature ones containing eggs. (Mature proglottids are essentially bags of eggs, each of which is infective to the intermediate host.
Encysted larvae within muscle meat of the host; When cysticerci are ingested by humans, all but the scolex is digested. (The scolex anchors itself to the small intestine and begins producing proglottids.)
A cyst formed in the tissues resulting from the development of certain tapeworm; May grow very, very large over a period of years.
a.k.a. Nematodes; Members of the Phylum Nematoda; They are cylindrical and are tapered at each end, have complete digestive systems (consisting of a mouth, intestine, and anus), and are dioecious. Males are smaller than females and have one or two hardened spicules on their posterior ends. [Some nematodes are free-living in soil and water, and others are parasites living on plants and animals. Some pass their entire life-cycle, from egg to mature adult, in a single host. 2 types of nematode infections: those which the egg is infective, and those which the larva is infective.]
The male and female worms look distinctly different., A special case of polymorphism based on the distinction between the secondary sex characteristics of males and females.
Parasitic worm; The adult stage is often in the animal host's heart, where it can kill its host through congestive heart failure.
Entities that: Contain a single type of nucleic acid (DNA or RNA), Contain a protein coat (sometimes itself enclosed by an envelope of lipids, proteins, and carbohydrates) that surround the nucleic acid, Multiply inside the living cells by using the synthesizing machinery of the cell, Cause the synthesis of specialized structures that can transfer the viral nucleic acid to other cells. Viruses have few or no enzymes of their own for metabolism. To multiply, they must take over the metabolic machinery of the host cell.
A complete, fully developed, infectious viral particle composed of nucleic acid and surrounded by a protein coat that protects it from the environment and is a vehicle of transmission from one host cell to another. Viruses are classified by differences in the structures of these coats.
Sometimes cover the capsid of a virus; Usually consists of some combination of lipids, proteins, and carbohydrates.
Dependent upon the virus, spikes may or may not cover the envelope. Spikes are carbohydrate-protein complexes that project from the surface of the envelope.
Some viruses, particularly bacterial viruses, that have complicated [or complex] structures.
A group of viruses sharing the same genetic information and ecological niche (host range).
Clearings which are visible against a lawn of bacterial growth on the surface of an agar plate.
Plaque-Forming Units (PFU)
The concentrations of viral suspensions measured by the number of plaques.
Diploid Cell Lines
Certain cell lines; Developed from human embryos, can be maintained for about 100 generations and are widely used for culturing viruses that require a human host.
Continuous Cell Lines
Transformed (cancerous) cells that can be maintained through an indefinite number of generations. They are sometimes called immortal cell lines.
A viral reproductive cycle in which copies of a virus are made within a host cell, which then bursts open, releasing new viruses. Ends with the lysis and death of the host cell. (1. Attachment, 2. Penetration, 3. Biosynthesis, 4. Maturation, 5. Release.)
A method of viral replication in which a viral genome is replicated as a provirus without destroying the host cell.
The period during viral multiplication when complete, infective virions are not yet present.
The final stage of viral multiplication is the release of virions from the host cell. The term lysis is used for the Release Stage in the multiplication of T-even phages because in this case the plasma membrane actually breaks open (lysis).
The phage remains latent (inactive). The participating bacterial host cells are known as lysogenic cells.
An active cellular process by which nutrients and other molecules are brought into a cell. A cell's plasma membrane continuously folds inward to form vesicles.
Alternative method by which enveloped viruses can enter; The viral envelope fuses with the plasma membrane and releases the capsid into the cell's cytoplasm. One example of a virus which penetrates cells using this method is the HIV virus.
Another result of lysogeny, bacterial genes can be picked up in a phage coat and transferred to another bacterium.
The separation of the viral nucleic acid from its protein coat once the virion is enclosed in the vesicle. The capsid is digested when the cell attempts to digest the vesicle's contents, or the non-enveloped capsid may be released into the cytoplasm of the host cell. (This process varies with the type of virus.)
Never comes out of the chromosome; Remains in its latent state and replicates when the DNA of the host virus replicates. In other words, the provirus is expressed and produces new viruses which infect adjacent cells.
Asexual reproduction in which a part of the parent organism pinches off and forms a new organism; Envelope develops around around the capsid by this process.
Tumor cells acquire properties that are distinct from the properties of uninfected cells or from infected cells that form tumors.
Tumor-Specific Transplantation Antigen (TSA)
Virus-specific antigen on cell surface of many tumor cells. (Tend to be less round than normal cells, and usually exhibit certain chromosomal abnormalities. i.e.- unusual numbers of chromosomes and fragmented chromosomes.)
Antigen in the nucleus of tumor cells. (Tend to be less round than normal cells, and usually exhibit certain chromosomal abnormalities. i.e.- unusual numbers of chromosomes and fragmented chromosomes.)
Phase in a cycle of an infection after initial onset and the multiplication of pathogens comes to a halt. Pathogen is still there. Common in viruses (Herpes Simplex, HIV, Epstein-Barr), Hepatitis B). NOT the same as remission.
Persistant/Chronic Viral Infection
Viral infection which occurs gradually over a long period. Typically, persistent viral infections are fatal.
A substance produced by microorganisms that in small amounts inhibits another microorganism.
Antibiotics that affect a broad range of gram-positive or gram-negative bacteria.
Infection that occurs while you are being treated for another infection. Growth of a target pathogen that has developed resistance to an antibiotic. (A secondary infection from the removal of normal microbiota, allowing colonizatiion by pathogenic, and often antibiotic resistant microbes.)
Para-Aminobenzoic Acid (PABA)
The substrate for an enzymatic reaction leading to the synthesis of folic acid, a vitamin that functions as a coenzyme for the synthesis of the purine and pyrimidine bases of nucleic acids and many amino acids.
Refers to a group of over 50 chemically related antibiotics, all of which have a common core structure containing a B-lactam ring called the nucleus. Penicillin molecules are differentiated by the chemical side chains attached to their nuclei. They can be produced either naturally or semisynthetically. They prevent the cross-linking of peptidoglycans, which interferes with the final stages of the construction of the cell walls, primarily gram-positive bacteria.
Penicillin extracted from cultures of the mold Penicillium exists in several closely related forms. These are the so-called natural penicillins. Natural penicillins have some disadvantages. (i.e.- their narrow spectrum of activity and their susceptibility to penicillinases.
Developed in attempts to overcome the disadvantages of natural penicillins. Part of the penicillin is produced by the mold, and the other part is added synthetically.
Methicillin-Resistant Staphylococcus Aureus (MRSA)
Resistant to methicillin, penicillin (PCN), etc. Normally found on skin, mucous membranes, in colon and vagina; Infections are in wounds, sputum, UTIs, blood and on skin following tattoo application; Spread by direct contact on the hands of HCWs; May remain on hands for up to 3 hours if not washed, surfaces for days.
Vancomycin-Resistant Enterococci (VRE)
Opportunistic, gram-positive pathogens that are particularly troublesome in hospital settings.
Very effective synthetic antimicrobial drug against Mycobacterium Tuberculosis; Primary effect of INH is to inhibit synthesis of mycolic acids, which are components of cell walls only of the mycobacteria.
Effective only against mycobacteria; Apparently inhibits incorporation of mycolic acid into the cell wall. It is a comparatively weak anti-tubercular drug; It's principal use is as the secondary drug to avoid resistance problems.
...A lot of other types of penicillin named and defined, however I'd rather focus on vocabulary other than each different type. (Review charts from text.)...
Occurs when drugs interact to produce effects greater than those that each drug would produce alone.
Antiviral drugs used in HIV patients, which inhibit the action of viral protease by binding directly to the catalytic site, preventing viral protein processing.
Block fusion of HIV with host cells before the virus enters the CD4 cell. Used in cases where standard therapies are not working. (Work by inhibiting the binding of HIV to cells.)
a.k.a. Kirby-Bauer test; A method used to determine microbial sensitivity to antimicrobial agents in which antibiotic disks are placed on an inoculated Petri dish, incubated, and observed for inhibition of growth.
Zone of Inhibition
A clear area that appears on agar in the disk diffusion method, in dictating where the antibiotic has inhibited growth of the organism.
A more advanced diffusion method; Enables a lab tech to estimate the minimal inhibitory concentration (MIC).
Minimal Inhibitory Concentration (MIC)
The lowest antibiotic concentration that prevents visible bacterial growth.
Minimal Bactericidal Concentration (MBC)
An extension of the MIC test in which samples taken from clear MIC tubes are transferred to plates containing a drug-free growth medium and monitored for bacterial replication.
Periodic reports kept by hospital personnel which record the susceptibility of organisms encountered clinically.
The chemotherapeutic effect of two drugs given simultaneously is sometimes greater than the effect of either given alone.
Small proteins secreted by epithelial cells that are toxic to certain bacteria, fungi, and viruses; Part of the defense systems of most forms of life. (Does not build a resistance.)
(The skin consists of two principal parts: the epidermis and the dermis.) The epidermis is the thin outer-portion, composed of several layers of epithelial cells.
(The skin consists of two principal parts: the epidermis and the dermis.) The dermis is the inner, relatively thick portion of the skin, composed mainly of connective tissue.
a.k.a. Mucosa; Sheets of lightly packed epithelial cells which are attached to the basement membrane (cells which are attached at their bases to a layer of extracellular material) and secrete mucous.
A highly contagious skin infection mostly affecting children 2-5 yrs. old; Symptoms include very itchy bumps, etc.
Scalded Skin Syndrome
A type of impetigo, bullous impetigo, is caused by a staphylococcal toxin and is a localized form of staphylococcal scalded skin syndrome.
"Impetigo of the newborn"; Outbreaks of bullous impetigo in hospital nurseries.
Toxic Shock Syndrome
Potentially life-threatening condition where fever, vomiting, and sunburn-like rash are followed by shock and sometimes organ failure, especially of the kidneys.
Deep infection of skin that involves destruction of muscle and fat layers, treated aggressively with antibiotics and surgical debridement of infected tissue. (Destroys tissue as rapidly as a surgeon can remove it.)
Streptococcal Toxic Shock Syndrome
Resembles Staphylococcal TSS, however a rash is less-likely to be present, but bacteremia is more likely to occur.
A self-limiting rash of about 2 weeks duration, often associated with swimming pools and suanas or hot tubs.
a.k.a. Swimmer's ear; A painful infection of the external ear canal leading to the eardrum that is frequently caused by pseudomonads.
Bluish-green color of Psuedomonas aeruginosa that stimulates the formation of superoxide radicalse and peroixde anions that result in tissue damage.
A disease found primarily in western and central Africa caused by Mycobacterium ulcerans, which is similar to the mycobacteria that causes tuberculosis and leprosy; Progresses slowly with few serious early signs or symptoms. Eventually, the result is a deep ulcer that often becomes massive and seriously damaging.
(Probably the most common skin disease in humans.) Can be classified by type of lesion into three categories: Comedonal Acne, Inflammatory Acne, and Nodular Cystic Acne.
Moderate acne arises from bacterial action; At this stage, therapy is usually focused on preventing formation of sebum. Topical agents are not effective, antibiotics are usually prescribed. (It can also be treated with non-prescription treatments that contain benzoyl peroxide.)
Nodular Cystic Acne
Severe acne characterized by nodules, or cysts, which are inflamed lesions filled with pus deep within the skin. These leave prominent scars on the face and upper body, which often leave psychological scars as well.
Caused by orthopoxvirus; Two basic forms: Variola Major (with a mortality rate of 20% or higher), and Variola Minor (with a mortality rate of less than 1%). Transmitted by the respiratory route.
First appeared in monkeys, but there are occasional outbreaks among humans; Closely resembles smallpox in symptoms (and was probably mistaken for it) and is known to jump from animals to humans, however transmission from human to human has been limited. Like smallpox, monkeypox is an "arthropoxvirus" and vaccination for smallpox has a protective effect.
An occasional severe complication of chickenpox, influenza, and some other viral diseases. A few days after the initial infection has receded, the patient persistently vomits and exhibits signs of brain dysfunction, such as extreme drowsiness or combative behavior; Coma and death may follow.
Vesicles, similar to those of chickenpox, occur but are localized in distinctive areas (typically about the waist); Limited to one side of the body at a time. The patient has partial-immunity to the virus.
Varicella in previously vaccinated persons; A relatively mild disease with a rash (which does not look like typical varicella); A booster dose of the vaccine may eventually be needed for complete control of varicella.
a.k.a. Cold Sores; Painful, short-lived vesicles that occur near the outer red margin of the lips.
Occurrence is often related to stress or menstruation; Similar to cold sores in appearance, however, they appear in different areas, i.e.- tongue, cheeks, inner surface of the lips.
Rarely, either type of the herpes simplex virus (HSV) may spread to the brain, causing herpes encephalitis. Infections of HSV-2 are more serious, with a fatality rate as high as 70% if untreated.
Acute Sclerosing Panencephalitis
Occurs about 1-10 yrs. after recovery from Measles; Severe neurological symptoms result in death within a few years.
a.k.a. German Measles; Mild viral disease, often goes undetected. Symptoms include a rash of small red spots and a light fever. The virus is transmitted by the respiratory route.
Congenital Rubella Syndrome
A type of in utero infection that infants contract from their mother while she is pregnant, and can lead to severe birth defects and disorders.
Fifth Disease/Erythema Infectiosum
Produces no symptoms at all in approx. 20% of infected individuals; Symptoms are similar to a mild case of influenza, but there is a distinctive facial rash that slowly fades; May cause anemia, an episode of arthritis, or, rarely, miscarriage, in adults.
Very common mild childhood disease; Symptoms include high fever for a few days, followed by a rash over much of the body lasting for a day or two. Recovery leads to immunity.
Fungi that colonize the hair, nails, and outer layer of the epidermis; They grow on the keratin present in loose locations.
a.k.a. Ringworm of the scalp; Fairly common among elementary school children; Can result in bald patches.
Disease which involves intense local itching and is caused by the tiny mite Sarcoptes scabiei burrowing under the skin to lay its eggs. The burrows are often visible as slightly elevated lines. Scabies may also appear as a variety of inflammatory skin lesions, many of them secondary infections from scratching. Transmitted by intimate contact.
Inflammation of the conjunctiva; Often referred to as red eye, or pink eye. Bacteria is the most common cause, however there is such thing as viral conjunctivitis.
A serious form of conjunctivitis caused by the same bacteria that causes gonorrhea. Large amounts of pus are formed; If treatment is delayed, ulceration of the cornea will usually result.
a.k.a. Chlamydial Conjunctivitis; Quite common today, it is caused by a bacterium that grows only as an obligate intracellular parasite. Tends to spread in unchlorinated waters of swimming pools as well as from mother to child during childbirth.
A serious eye infection, and probably the greatest single cause of blindness by an infectious disease; Caused by certain serotypes of Chlamydia trachomatis but not the same ones that cause genital infections.
Caused by the same herpes simplex type 1 (HSV-1) that causes cold sores and is latent in the trigeminal nerves. The disease is an infection of the cornea, often resulting in deep ulcers, that may be the most common cause of infectious blindness in the U.S.