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

2. Fungal Diseases Candidiasis Dermatophytosis Cryptococcosis
Histoplasmosis
Blastomycosis
Pneumocystosis

3. 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)

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

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

12. 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

13. 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

14. 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

15. 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

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

17. 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

18. 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

19. 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

20. 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

21. 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

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

23. 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 hr after exposure, due to the simultaneous rupture of so many erythrocytes

24. 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

25. 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