Overview and Types of Fungal Infections

Sources and sites of Systemic fungal infections

Lab Tests Online posted on its website this very informative article:

(Lab Tests Online is produced by The American Association for Clinical Chemistry (AACC))

What are fungal infections?

Fungal infections represent the invasion of tissues by one or more species of fungi. They range from superficial, localized skin conditions to deeper tissue infections to serious lung, blood (septicemia) or systemic diseases. Some fungi are opportunistic while others are pathogenic, causing disease whether the immune system is healthy or not.
Fungi are one of four major groups of microorganisms (bacteria, viruses, parasites, and fungi). They that exist in nature in one of two forms: as unicellular yeasts or as branching filamentous molds (also may be spelled as “moulds”). Some fungi are dimorphic – they change from one form to another depending on their environment. While yeasts cannot be seen with the naked eye, molds can be seen as the fuzzy splotches on overripe fruit or stale bread, as mildew in the bathroom shower, and as mushrooms growing on a rotted log. There are more than 50,000 species of fungi in the environment, but less than 200 species are associated with human disease. Of these, only about 20 to 25 species are common causes of infection.

Most fungal infections occur because a person is exposed to a source of fungi such as spores on surfaces or in the air, soil, or bird droppings. Usually, there is a break or deficiency in the body’s immune system defenses and/or the person provides the “right environment” for the fungi to grow. Anyone can have a fungal infection, but certain populations are at an increased risk of fungal infections and recurrence of infections. These include organ transplant recipients, people who have HIV/AIDS, those who are on chemotherapy or immune suppressants, and those who have an underlying condition such as diabetes or lung disease.

Infections involving fungi may occur on the surface of the skin, in skin folds, and in other areas kept warm and moist by clothing and shoes. They may occur at the site of an injury, in mucous membranes, the sinuses, and the lungs. Fungal infections trigger the body’s immune system, can cause inflammation and tissue damage, and in some people may trigger an allergic reaction.

Many infections remain confined to a small area, such as between the toes, but others may spread over the skin and/or penetrate into deeper tissues. Those that progress and those that start in the lungs may move into the blood and be carried throughout the body. Some fungal infections may resolve on their own, but most require medical attention and may need to be treated for extended periods of time. Those that penetrate into the body typically increase in severity over time and, if left untreated, may cause permanent damage and in some cases eventually be fatal. A few fungal infections may be easily passed on to other people, while others typically only affect the infected person.
Fungal infections may be categorized by the part of the body that they affect, by how deeply they penetrate the body, by the organism causing the infection, and by the form(s) that the fungi take. Some organisms may cause both superficial and systemic infections.

Superficial fungal infections of skin, nail, and hair

Superficial fungal infections may be caused by both yeast and mold forms of fungi. Skin is normally populated with a mixture of microorganisms called normal flora. Most of the time, normal flora do not cause illness and do not stimulate the immune system. If there is a break in the skin or if the immune system becomes compromised, then any of the microorganisms present can cause a wound or skin infection. If there is a shift in the balance of the microorganisms, such as a decrease in bacteria and an increase in the growth of fungi (sometimes seen with the use of broad-spectrum antibiotics), then the person may experience a fungal infection associated with the imbalance.

Yeast infections

Candidiasis, is a common yeast infection that is due primarily to the overgrowth of Candida albicans and other species of Candida, which are part of the normal flora. In the mouth, candidiasis causes redness and white patches and is called “thrush.” In babies, Candida can cause diaper rash. In women, it can cause genital itching and vaginal discharge that is referred to as a “yeast infection.” According to the Centers for Disease Control and Prevention (CDC), almost 75% of women will have at least one yeast infection in their lifetime. Candidiasis can also cause a variety of other infections, including nail infections, and can become systemic – especially in those who are immunocompromised. It is currently the fourth most common cause of hospital-acquired septicemia in the United States.

Fungal (dermatophyte) infections
Athlete’s foot, jock itch, and fungal nail infections are common infections that can be passed from person to person. These fungal infections can cause reddening, peeling, blistering, and scaling of the skin, itching, deformation and brittleness of affected nails, and brittle hair. They are caused by dermatophytes, a group of fungi that includes Trichophyton, Microsporum, and Epidermophyton species. Dermatophytes feed on keratin and rarely penetrate below the skin. Infections caused by these fungi are also commonly called ringworm (although they are not caused by a worm) and “tinea.”

Athlete’s foot (tinea pedis) is found between the toes and sometimes covers the bottom of the foot.
Jock itch (tinea cruris) may extend from the groin to the inner thigh.
Scalp and hair infection (tinea capitis) affects hair shaft, primarily in children.
Finger or toenail infection (tinea unguium) typically affects toenails but may also affect fingernails.
Ringworm of the body (tinea corporis) can be found anywhere on the body.
Barber’s itch (tinea barbae) affects the bearded portion of the face.

Others
Tinea versicolor is associated with multicolored patches or lesions on the skin and is caused not by a dermatophyte, but by Malassezia furfur, a yeast. It is a condition that is common in young adults. Sporotrichosis is a condition caused by the fungus Sporothrix schenckii, which is not a dermatophyte. It is an infection of the skin and subcutaneous tissue that has been abraided by thorny plants, pine needles, and sphagnum moss where this fungus normally resides.

Deep Tissue, Blood, Lung and Systemic Fungal Infections

A variety of fungi can cause deep and systemic infections. Some are found throughout the U.S. while others are found in specific regions. People frequently become infected because they come in contact with the environment where a fungus grows, such as infected soil. Lung infections typically start with the inhalation of fungal spores. With lung infections, and with fungal infections that have spread below the surface of the skin, the invading fungi have the potential to disseminate from the original infection location and move to the blood (septicemia) and/or spread throughout the body – into organs, tissues, bone, and sometimes into the meninges that cover the spinal cord, and into the brain.

In many patients with competent immune systems, fungal lung infections may cause only mild to moderate flu-like symptoms such as coughing, fever, muscle aches, headaches, and rashes. In other patients, fungi may cause infections that remain localized at the initial site of the infection and do not spread (the organisms are walled off in granulomas). However, people with these localized infections may, at some point in their life, become immunocompromised and the long-standing, silent chronic fungal infection may then become an active acute infection. Some infections caused by fungi may take months to years to cause symptoms, slowly and progressively growing worse and disseminating throughout the body, causing night sweats, chest pain, weight loss, and enlarged lymph nodes. Others may progress rapidly, causing pneumonia and/or septicemia. Fungal lung infections are more likely to be severe in people who have underlying lung disease and/or compromised immune systems such as those with HIV/AIDS. Both acute and chronic fungal infections can cause permanent lung, organ, and bone damage and can be fatal. Common deep or systemic infections include:

Aspergillosis, caused by Aspergillus fumigatus or several other Aspergillus species. These fungi are commonly found in soil, plants, and house dust. They can cause fungal masses in the sinuses and lungs and, in some cases, can spread to the brain and bones.
Blastomycosis, caused by Blastomyces dermatitidis found in moist organic-rich soil, such as woodland areas of the south-eastern and south-central United States.
Coccidiomycosis, caused primarily by Coccidioides immitis found in arid soil of the southwestern U.S., Mexico, and South America.
Cryptococcosis, caused by Cryptococcus neoformans or rarely by another Cryptococcus species found in soil and are associated with bird droppings. Anyone may become infected, but the highest prevalence in the U.S. is in people who have HIV/AIDS.
Histoplasmosis, caused by Histoplasma capsulatum found primarily in the east and central U.S.; typically affects the lungs.
Candidiasis, caused by Candida species, which are part of the normal human flora, are found worldwide. Infections occur in the moist mucous membranes of the body.
Pneumocystis pneumonia, caused by Pneumocystis jorveci (formerly known as Pneumocystis carinii), found worldwide and most commonly affecting those with compromised immune systems, including those with HIV/AIDS.

Note: This article was last reviewed on October 20, 2008.  |  This article was last modified on April 28, 2011

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Another very helpful article is written by Dr Pooja posted on HubPages is:

An introduction to medically relevant fungal infections

Once considered as the causative agents of benign (mild) infections like athlete’s foot, favus and thrush; fungi are now increasing associated with highly serious and fatal infections like Cryptococcosis seen in patients with AIDS. Increasingly there are certain groups of fungi that cause disease both allergic and non-allergic infections in individuals with normal immune status.
Fungi are eukaryotes and possess true nuclei, nuclear membrane with paired chromosome and divide by sexual, asexual or both modes.

Types of fungi

Yeasts are the simplest type of fungi. They are made of single cell and divide by budding.
Yeast like fungi: They are called so as they exist both as yeast and as elongated cells called hyphae. Candida belong to these category.
Moulds:Also termed as filamentous fungi .one which we all know are the dermatophytes. They reproduce by various types of spores.
Dimorphic fungi can grow both as yeast cells and moulds depending on conditions of growth. They occur as moulds in human bodies (37 °c) and as yeast in soil or at 22°C. Fungi causing systemic infections belong to this category.

Source google images

What is Mycosis?

Fungal infections of human and animals are called Mycoses .Depending on location of infection mycoses are of two types
Superficial:We all have heard and seen infections like ringworm infections which affect skin,hair and nails.These infections are mild but chronic .
Systemic infections: These are caused by fungi which are normally soil saprophytes and accidentally infect humans or animals. Broken skin or cuts and abrasions get infected with spores of fungus .Depending upon host immune status infections can be asymptomatic or fatal.
In the era of medical advance and antibiotics we see a new variety of fungal infection called the Opportunistic infections which were not known years ago. Patients with following risk factors are predisposed to such infections:
· Patients with cancer or on chemotherapy
· High dose of immunosuppressive drugs, steroids and x-rays
· Congenital or acquired immunodeficiency states like HIV infection
The most commonly encountered fungal infections include ringworm infections (Tinea) which are caused by a group of fungi called dermatophytes which infect superficial keratin layer of skin, hair and nail. Most of these infections are labelled according to site of body which they infect and can also bear names in local language.
Yeast infection is a nonspecific term which generally includes infections of the mucosa caused by Candida like oral thrush, candida vaginitis. Candida can also cause skin and nail infections.
Accurate and early diagnosis is done using microscopy and culture. Wet films and gram stain show presence of budding yeast. A word of caution is important here as Candida is present as normal flora on skin and mucosa and hence demonstration of invasiveness indicates its disease causing potential.

Budding yeast cells

Light bites of Fungi !!!

· It is estimated that there are over a million kinds of fungi but only about 10% are currently described.
· Fungi cause an economic loss close to 4 billion dollars annually due to the impact on agricultural produce as they can cause disease of plants.
· Some of the plant fungi are related to the release of the highest amounts of carbon dioxide into the atmosphere up to over 110 million tonnes!!!!
· Fungi are responsible for the millions of gallons of beer that is consumed by the entire population in the world apart from this tonnes of bread are made by using fungi of different variety.
· Drugs including anti-cancer drugs and antibiotics are manufactured using fungi as well including vaccines that we have taken like for example Hepatitis B vaccine.
(Last updated on May 7, 2012)