Selected Fungal and Protozoan Diseases Updated Spring 2015 Jerald D. Hendrix

Fungal Diseases Candidiasis Dermatophytosis Cryptococcosis Histoplasmosis Blastomycosis Pneumocystosis

Candidiasis Cause: Candida albicans and several other species of the genus Candida An ascomycete Grows as yeast or pseudohyphae, dependent on cultural conditions (dimorphic) Very common normal flora in mouth, intestinal tract, and vaginal tract Many cases due to antibiotic usage (decreased bacterial flora to compete with Candida) and compromised immunity (such as AIDS)

Candidiasis Symptoms Mucosal candidiasis: Oral candidiasis (thrush), esophageal candidiasis, intestinal candidiasis, candidal vulvovaginitis, candidal balanitis Cutaneous candidiasis and candidal onychomycosis Systemic candidiasis: Candidal septecemia and liver damage

Dermatophytosis Cause: Several genera of dermatophytic fungi Trichophyton, an ascomycete Microsporum, an ascomycete Epidermophyton, an ascomycete Grow on skin, hair, nails Transmitted by contact with infected persons or animals

Dermatophytosis Symptoms Tinea infections: Red, scaly or blister-like lesions; often a raised red ring; “ringworm” Used together with Latin name of the body part: Tinea pedis Tinea corporis Tinea capitis Tinea barbae Tinea cruris Tinea unguium

Cryptococcosis Cryptococcus neoformans and Cryptococcus gattii A basidiomycete Spores in contaminated soil; esp. contaminated with bird droppings Airborne to humans Gelatinous capsules resist phagocytosis Respiratory tract infections Occasional systemic infections involving brain & meninges

Histoplasmosis An ascomycete Histoplasma capsulatum Airborne infection Transmitted by inhalation of spores in contaminated soil Associated with chicken & bat droppings Respiratory tract symptoms; fever, headache, cough, chest pains

Blastomycosis Blastomyces dermatitidis An ascomycete Associated with dusty soil & bird droppings Skin transmission: via cuts & abrasions Raised, wart-like lesions Airborne transmission: via inhalation of spores Respiratory tract symptoms Occasional internal infections with high fatality rate

Pneumocystosis Pneumocystis jirovecii (formerly Pneumocystis carinii) An ascomycete Transmitted by airborne contact Usually asymptomatic or with mild respiratory symptoms Causes severe pneumonia in immunocompromised persons A major secondary infection & cause of death in AIDS patients

Protozoan Diseases Amebiasis Primary Amebic Meningoencephalitis Giardiasis Trichomoniasis Balantidiasis Toxoplasmosis Malaria Cryptosporidiosis

Amebiasis Cause: Entamoeba histolytica A parasitic amoeba Transmitted via contaminated food & water Cysts are shed in the feces When ingested: Excystation occurs in the intestine Trophozoites grow & reproduce in the intestinal tract

Amebiasis Symptoms Abdominal pain Little diarrhea but often blood in the stool (“amebic dysentery”) Possibly of intestinal ulceration; perforation; infection of internal organs such as liver & lungs

Primary Amebic Meningoencephalitis Cause: Naegleria fowleri A fresh water, free living ameba No cyst stage Several cases of infections in swimmers Transmission and Symptoms: Transmission through the nasal & sinus passages Infection of the brain & meninges Headaches; delirium; seizures

Giardiasis Cause: Giardia lamblia A flagellated diplomonad The trophozoite has four pairs of flagella & two nuclei; giving it a face-like appearance Grows in the intestinal tract Cysts are shed in the feces

Giardiasis Transmission and Symptoms Transmitted via contaminated water & food Foul-smelling profuse diarrhea Sometimes chronic Often misdiagnosed Diagnosis via microscopic examination Enterotest capsule

Trichomoniasis Cause: Trichomonas vaginalis Transmission & Symptoms Flagellated parabasalid No cyst stage Transmission & Symptoms Transmitted via sexual contact Genital itching Painful urination with a white, mucoid discharge Occasional reduction of sperm count or erosion of the cervix

Balantidiasis Cause: Balantidium coli Transmission & Symptoms Ciliated alveolate Trophozoites grow in the intestinal tract Cysts are shed in the feces and may remain embedded in intestinal walls, causing chronic infections Transmission & Symptoms Contaminated water & food Ulceration in intestines Profuse diarrhea

Toxoplasmosis Cause: Toxoplasma gondii Alveolate apicomplexian Both asexual & sexual stages Invasion of several areas of the body, including internal organs & muscle tissue Possibly the most prevalent protozoan parasite of humans

Toxoplasmosis Transmission & Symptoms Transmitted via eating contaminated meat Cysts are found in the meat, especially of grazing animals such as cattle Cats can transmit the disease through their feces Lymph node swelling; flu-like symptoms

Toxoplasmosis Transmission & Symptoms (cont.) Generally mild in non-immunosuppressed persons Severe infections in immunosuppressed persons Pregnant women are in danger of fetal damage or miscarriage

Malaria Cause: Plasmodium species Alveolate apicomplexian Complex life cycle requiring two hosts: a mammal (human) and the mosquito Anopheles

Malaria Transmission and Symptoms The asexual merozoite stage infects human blood from the bite of a mosquito The parasite invades erythrocytes & reproduces Erythrocytes break open & release the parasite; this causes the characteristic fever, chills, anemia, weakness, hemorrhaging Intense fever & chills about 48 - 72 hr after exposure, due to the simultaneous rupture of so many erythrocytes

Malaria Transmission and Symptoms (cont.) The sexual stage of Plasmodium develops in the human host and is picked up by a mosquito The sexual stage is completed in the salivary gland of the mosquito to complete the cycle Treatment by quinine & other antimalarial drugs

Cryptosporidiosis Cause: Cryptosporidium species Alveolate apicomplexian A common protozoan parasite in humans Transmission and Symptoms Contaminated water Mild diarrhea in non-immunosuppressed persons Severe diarrhea in immunosuppressed persons