Fungal Infections

Histoplasmosis Systemic infection by Primary pathogen Causative agent: Histoplasmosis capsulatum Most common true pathogen Typically dimorphic H. capsulatum grows in soil and material contaminated with bat or bird droppings. (droppings from chickens, pigeons, blackbirds also support its growth) The microscopic fungal spores can become airborne when the soil is disturbed, and breathing in the spores can cause infection in the lungs Most prevalent in eastern & central regions of the US

Histoplasmosis H. capsulatum thrives in moderate temperatures & moist environment Cannot be transmitted from person to person Many people who are infected with the fungus do not show any symptoms  If symptoms occur, they usually start within 3 to 17 days after being exposed to the fungus In people who develop disease, the most common symptoms are similar to those of pneumonia, and include: fever, chest pains, and a dry or nonproductive cough

Histoplasmosis Multiple tests available to diagnose Histoplasmosis Blood Sputum Bone marrow Liver, or skin By looking at a small sample of infected tissue under a microscope The mild pulmonary (lung) form of histoplasmosis will generally resolve within about a month without treatment. Prescription antifungal medications are needed to treat severe cases of acute histoplasmosis, and all cases of chronic or disseminated disease

Coccidioidomycosis: Valley Fever Systemic infection by Primary pathogen Causative agent: coccidioides immitis The most virulent of all fungal pathogens Distinctive morphology Blocklike arthroconidia in the free living stage & spherules containing endospores in the lungs Lives in the soil of dry, low rainfall areas

Coccidioidomycosis: Valley Fever The disease is found mainly in the southwestern United States, Mexico and Central and South America Dry weather coupled with sparse foliage and high winds provides the ideal condition for the spores to be airborne Transmission is generally by inhalation of spores found in the soil in endemic areas

Coccidioidomycosis: Valley Fever In 60% of cases infection is asymptomatic In 40% of cases include flu-like symptoms (cough, fever, sore throat, chills, headache, and in some cases itchy rash) that go away on their own Rare (5/1000), advanced coccidioidomycosis includes: skin lesions, chronic pneumonia, bone or joint infection Imaging tests- CT scans, x-rays of the lungs In many cases, treatment is not necessary Prescription of antifungal medications, such as amphotericin B & fluconazole, to prevent a more severe infection from developing

Dermatophytes Pathogens with Intermediate virulence Derma “skin” and plant “phyte” Common fungal infections that may occur anywhere on the skin, hair, and nail infections. All are communicable diseases Among humans, animals, and soil Many different species of dermatophytes that can cause infection in humans. Two of the most common types are Trichophyton rubrum and Trichophyton tonsurans, which are usually transmitted from person to person. T. rubrum T. tonsurans

Dermatophytes Dermatophytes like to live on moist areas of the skin, such as places where there are skin folds. They can also live on household items, such as clothing, towels, and bedding. Most diseases are termed “ringworm” or tinea because they develop in circular scaly patches

Dermatophytes The work tinea followed by the Latin term for the part of the body infected, is often used. Tinea capitis (head) Tinea corporis (body) Tinea pedis (foot) Tinea manuum (hand) Tinea unguium (nail)

Tinea capitis Sometimes called “ringworm of the scalp” Primarily affects school-aged children More common in large cities and overcrowded conditions Reservoir for most organisms is humans , some have animal hosts Incubation is 10 to 14 days

Tinea capitis Transmission Symptoms By direct or indirect contact Backs of theater seats Barber clippers Combs/hairbrushes Clothes Animals can also transmit the infection and sometimes are carriers If the infection involves the scalp or beard, hair may fall out Begin as small papules and spread across the head Hair in the infection area become brittle and break off easily

Tinea capitis Diagnosis is through physical examination Particular medication and duration of treatment depends on the location of the infection Topical treatment alone usually is ineffective and is not recommended for the management of tinea capitis Scalp infections usually require treatment with an oral antifungal medication (for at least 4 weeks) If secondary infection, antibiotics can be used

Tinea pedis Fungus infection of the foot especially between the toes Commonly called “athlete’s foot” Most common of all fungal skin diseases Infects adults more often than children, and males more often than females More often and more severe in hot weather Warm, moist conditions (between sweaty toes)

Tinea pedis Transmission Symptoms By direct or indirect contact with skin of an infected individual or lesion of infected animals Floors, shower stalls, benches, and similar location can also be a source of infection Scaling or cracking between the toes and watery blisters In severe cases- lesions may appear on other parts of the body particularly the hands Itching can be severe Exposure to public surfaces

Tinea pedis Based on symptoms and physical examinations Can be treated with topical antifungal medications. Fungicide in salve or powder form should be applied after every bath or shower Salve is a lotion ointment or paste

Candidiasis- “yeast infections” Infection by Secondary pathogen Causative agent: most common is Candida albicans Infections can be short-lived, superficial skin irritations to overwhelming, fatal systemic diseases Budding cells of varying size that may form both elongate pseudohyphae and true hyphae

Candidiasis Candida yeasts normally live on the skin and mucous membranes without causing infection Overgrowth of these organisms can cause symptoms to develop Candidiasis is usually endogenous Can also be communicable

Oropharyngeal Candidiasis Candidiasis that develops in the mouth or throat is called “thrush” or oropharyngeal candidiasis The most common symptom is white patches or plaques on the tongue and other oral mucous membranes Other symptoms include: Redness or soreness in the affected areas Difficulty swallowing Cracking at the corners of the mouth (angular cheilitis)

Oropharyngeal Candidiasis-Symptoms Uncommon in adults who are otherwise healthy Can affect normal newborns Newborns can develop thrush from mothers with a vaginal “yeast infection” at delivery Symptoms begin 7-10 days after birth Diagnoses based on symptoms Taking a scraping of the affected areas to examine under a microscope Candida infections of the mouth and throat must be treated with prescription antifungal medication The type and duration of treatment depends on the severity of the infection

Candidiasis-Genital/Vulvovaginal Genital / vulvovaginal candidiasis (VVC) is also sometimes called a "yeast infection.” Occurs when there is overgrowth of Candida Imbalances Normal acidity of the vagina changes or when hormonal balance changes Transmission: endogenous infection or contact with excretions or secretions of infected individuals Women with VVC usually experience genital itching, burning, and sometimes a "cottage cheese-like" vaginal discharge Men with genital candidiasis may experience an itchy rash on the penis Candida can multiply

Candidiasis-Genital/Vulvovaginal Nearly 75% of all adult women have had at least one "yeast infection" in their lifetime Wearing cotton underwear may help to reduce the risk of developing a yeast infection. Symptoms are similar to those of many other genital infections can be difficult to diagnose a yeast infection by physical examination only Usually the diagnosis is made by taking a sample of the vaginal secretions and looking at the sample under a microscope to see if an abnormal number of Candida organisms are present

Candidiasis-Genital/Vulvovaginal Treatment Antifungal vaginal suppositories or creams are commonly used Duration of the treatment course of creams and suppositories can range from one day to seven days of therapy Mild or moderate infections can sometimes be treated with a single dose of oral antifungal medication Over-the-counter treatments for VVC are available

Aspergillosis Infection by a secondary pathogen Causative agent: Aspergillus Distinguished by septate mycelium with characteristic conidial heads Common fungus that can be found in indoor and outdoor environments Found in soil, on plants, and on decaying organic matter Also found on household dust, and building material Aspergillus flavus

Aspergillosis There are many different species of Aspergillus Aspergillus flavus There are many different species of Aspergillus 8 involved in human disease Most common species are Aspergillus fumigatus and Aspergillus flavus Different kinds of aspergillosis allergic bronchopulmonary aspergillosis (also called ABPA) aspergilloma invasive aspergillosis Transmission: through inhalation of spores Most people breathe in Aspergillus spores every day without being affected Inhalation of spores causes fungus balls in lungs and invasive disease in the eyes, heart, & brain

Aspergillosis The different kinds of aspergillosis can cause different symptoms Symptoms of allergic bronchopulmonary aspergillosis (ABPA) may include: Wheezing Coughing Fever (in rare cases) Aspergilloma “fungus ball” Symptoms of invasive aspergillosis may include: Fever Chest pain Shortness of breath Other symptoms may develop if the infection spreads beyond the lungs. When invasive aspergillosis spreads outside of the lungs, it can cause symptoms in almost any organ.

Aspergillosis ABPA can affect people who are otherwise healthy, but it is most common in people with asthma or cystic fibrosis Invasive aspergillosis generally affects people who have weakened immune systems Those who have had a bone marrow transplant or solid organ transplant, people who are taking high doses of corticosteroids, and people who are getting chemotherapy for cancer. Healthcare providers consider symptoms Further testing may include imaging tests such as x-rays or CT scans of the lungs, biopsies of affected tissue and samples may be analyzed for evidence of the fungus Requires treatment with antifungal medication prescribed by a doctor In the more invasive form, the fungus produces a necrotic pneumonia and disseminates to the brain