Table 2.
Distribution of the most common organisms by region and reservoir
| Infectious etiology | Geographical origin | Reservoir/source | Main type of transmission |
|---|---|---|---|
| Viruses | |||
| MERS-CoV | Middle East | Dromedary camels | Droplet contact |
| SARS-CoV | South China | Chinese horseshoe bats | Droplet contact, airborne |
| H7N9 | Poultry, wild birds | Droplet | |
| Influenza virus | Eastern China, Hong Kong, Taiwan | Droplet | |
| Bacteria | |||
|
Streptococcus pneumoniae Haemophilus influenzae Chlamydophila pneumoniae Mycoplasma pneumoniae |
Worldwide | Human | Close contact with infected respiratory secretions; Droplet |
| Legionella pneumophila | Worldwide | Contaminated water source | Inhalation of contaminated aerosol |
| Burkholderia pseudomallei | Southeast Asia, Northern Australia | Soil/contaminated water | Inhalation, ingestion, or direct contact with contaminated soil or water |
| XDR-TB and MDR-TB | Eastern Europe, Russia, Southern Africa | Human | Airborne |
| Fungi | |||
| Histoplasma capsulatum | Worldwide | Bats, birds, contaminated soil | Inhalation of contaminated aerosol |
| Coccidioides immitis | Unites States (California, Arizona, New Mexico, Texas); Central America and South America | Contaminated soil | Inhalation of contaminated aerosol |
| Paracoccidioides brasiliensis | Central and South America | Contaminated soil, armadillo | Inhalation of contaminated aerosol |
| Blastomyces dermatitidis | United States (Wisconsin, Illinois, Tennessee, Arkansas), India, South America, Africa | Contaminated soil, beaver, dog, rodent | Inhalation of contaminated aerosol |
| Parasites | |||
| Strongyloides Stercoralis | Tropics and subtropics | Dogs and primates | Skin penetration by filariform larvae; autoinfection |
MERS-CoV Middle East respiratory syndrome coronavirus, SARS-CoV severe acute respiratory syndrome coronavirus, XDR-TB extensively drug-resistant tuberculosis, MDR-TB multidrug-resistant tuberculosis
Adapted from Ref. [84]