Fungal Infections

Fungal InfectionsHistoplasmosisSystemic infection by Primary pathogenCausative agent: Histoplasmosis capsulatum Most common true pathogenTypically dimorphicH. 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 lungsMost prevalent in eastern & central regions of the US

HistoplasmosisH. capsulatum thrives in moderate temperatures & moist environmentCannot be transmitted from person to personMany 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 fungusIn 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

HistoplasmosisMultiple tests available to diagnose HistoplasmosisBloodSputumBone marrowLiver, or skinBy 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

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Coccidioidomycosis: Valley FeverSystemic infection by Primary pathogenCausative agent: coccidioides immitisThe most virulent of all fungal pathogensDistinctive morphologyBlocklike arthroconidia in the free living stage & spherules containing endospores in the lungsLives in the soil of dry, low rainfall areas

The disease is found mainly in the southwestern United States, Mexico and Central and South AmericaDry weather coupled with sparse foliage and high winds provides the ideal condition for the spores to be airborneTransmission is generally by inhalation of spores found in the soil in endemic areas

Coccidioidomycosis: Valley Fever

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

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DermatophytesPathogens with Intermediate virulenceDerma skin and plant phyteCommon fungal infections that may occur anywhere on the skin, hair, and nail infections. All are communicable diseasesAmong humans, animals, and soilMany 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. rubrumT. tonsuransDermatophytesDermatophytes 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

DermatophytesThe 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 capitisSometimes called ringworm of the scalp Primarily affects school-aged childrenMore common in large cities and overcrowded conditionsReservoir for most organisms is humans , some have animal hostsIncubation is 10 to 14 days

Tinea capitisTransmissionSymptomsBy direct or indirect contactBacks of theater seatsBarber clippersCombs/hairbrushesClothesAnimals can also transmit the infection and sometimes are carriers

If the infection involves the scalp or beard, hair may fall outBegin as small papules and spread across the head Hair in the infection area become brittle and break off easily

Tinea capitisDiagnosis is through physical examinationParticular medication and duration of treatment depends on the location of the infectionTopical treatment alone usually is ineffective and is not recommended for the management of tinea capitisScalp infections usually require treatment with an oral antifungal medication (for at least 4 weeks)

If secondary infection, antibiotics can be used15Tinea pedisFungus infection of the foot especially between the toes

Commonly called athletes 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 pedisTransmissionBy 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 infectionSymptomsScaling 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 surfaces17Tinea pedisBased on symptoms and physical examinationsCan 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 paste18Candidiasis- yeast infectionsInfection by Secondary pathogenCausative agent: most common is Candida albicansInfections can be short-lived, superficial skin irritations to overwhelming, fatal systemic diseasesBudding cells of varying size that may form both elongate pseudohyphae and true hyphae

CandidiasisCandida yeasts normally live on the skin and mucous membranes without causing infectionOvergrowth of these organisms can cause symptoms to develop

Candidiasis is usually endogenousCan also be communicable

20Oropharyngeal CandidiasisCandidiasis that develops in the mouth or throat is called thrush or oropharyngeal candidiasisThe 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 areasDifficulty swallowingCracking at the corners of the mouth (angular cheilitis)

21Uncommon in adults who are otherwise healthyCan affect normal newbornsNewborns can develop thrush from mothers with a vaginal yeast infection at deliverySymptoms begin 7-10 days after birthDiagnoses based on symptoms Taking a scraping of the affected areas to examine under a microscopeCandida infections of the mouth and throat must be treated with prescription antifungal medicationThe type and duration of treatment depends on the severity of the infection

Oropharyngeal Candidiasis-Symptoms

Genital / vulvovaginal candidiasis (VVC) is also sometimes called a "yeast infection. Occurs when there is overgrowth of CandidaImbalancesNormal acidity of the vagina changes or when hormonal balance changesTransmission: endogenous infection or contact with excretions or secretions of infected individualsWomen with VVC usually experience genital itching, burning, and sometimes a "cottage cheese-like" vaginal dischargeMen with genital candidiasis may experience an itchy rash on the penis

Candidiasis-Genital/VulvovaginalCandida can multiply23Nearly 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 infectionscan be difficult to diagnose a yeast infection by physical examination onlyUsually 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

TreatmentAntifungal vaginal suppositories or creams are commonly usedDuration 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 medicationOver-the-counter treatments for VVC are available

Candidiasis-Genital/Vulvovaginal

AspergillosisInfection by a secondary pathogenCausative agent: AspergillusDistinguished by septate mycelium with characteristic conidial headsCommon fungus that can be found in indoor and outdoor environmentsFound in soil, on plants, and on decaying organic matter

Also found on household dust, and building material

Aspergillus flavusAspergillosisThere are many different species of Aspergillus8 involved in human diseaseMost common species are Aspergillus fumigatus and Aspergillus flavus

Different kinds of aspergillosisallergic bronchopulmonary aspergillosis (also called ABPA)aspergillomainvasive aspergillosis

Transmission: through inhalation of spores Most people breathe in Aspergillus spores every day without being affectedInhalation of spores causes fungus balls in lungs and invasive disease in the eyes, heart, & brain

Aspergillus flavusAspergillosis

The different kinds of aspergillosis can cause different symptoms

Symptoms of allergic bronchopulmonary aspergillosis (ABPA) may include: WheezingCoughingFever (in rare cases)

Aspergilloma fungus ball

Symptoms of invasive aspergillosis may include: FeverChest painCoughingShortness 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.

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AspergillosisABPA 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 systemsThose 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 symptomsFurther 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 necroticpneumonia and disseminates to the brain30