Agent

Related Diseases/Symptoms

Mode of Transmission

Cause(s) of Emergence

Babesia

Babesiosis: fever, fatigue, hemolytic anemia

Bite of an Ixodes tick (carried by mice in the presence of deer)

Reforestation; increase in deer population; changes in outdoor recreational activity

Candida

Candidiasis: fungal infections of the gastrointestinal tract, vagina, and oral cavity

Endogenous flora; contact with secretions or excretions from infected persons

Immunosuppression; medical management (catheters); antibiotic use

Cryptococcus

Meningitis; sometimes infections of the lungs, kidneys, prostate, liver

Inhalation

Immunosuppression

Cryptosporidium

Cryptosporidiosis: infection of epithelial cells in the gastrointestinal and respiratory tracts

Fecal-oral, person-to-person, waterborne

Development near watershed areas; immunosuppression

Giardia lamblia

Giardiasis: infection of the upper small intestine, diarrhea, bloating

Ingestion of fecally contaminated food or water

Inadequate control in some water supply systems; immunosuppression; international travel

Microsporidia

Gastrointestinal illness, diarrhea; wasting in immunosuppressed persons

Unknown; probably ingestion of fecally contaminated food or water

Immunosuppression; recognition

Plasmodium

Malaria

Bite of an infective Anopheles mosquito

Urbanization; changing parasite biology; environmental changes; drug resistance; air travel

Pneumocystis carinii

Acute pneumonia

Unknown; possibly reactivation of latent infection

Immunosuppression

Strongyloides stercoralis

Strongyloidiasis: rash and cough followed by diarrhea; wasting, pulmonary involvement, and death in immunosuppressed persons

Penetration of skin or mucous membrane by larvae (usually from fecally-contaminated soil); oral-anal sexual activities

Immunosuppression; international travel

Toxoplasma gondii

Toxoplasmosis: fever, lymphadenopathy, lymphocytosis

Exposure to feces of cats carrying the protozoan; sometimes foodborne

Immunosuppression; increase in cats as pets



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