Risk Factor |
Cause |
None (healthy) |
Upper or lower respiratory tract infection Gastrointestinal infection |
Infection related to a catheter inserted in a vein (IV catheter infection) Urinary tract infection, particularly in people with a urinary catheter Pneumonia, particularly in people on a ventilator Atelectasis (collapse of part of a lung due to an airway blockage, rather than an infection) Infection or a pocket of blood (hematoma) at the site of surgery Diarrhea (due to Clostridioides difficile–induced colitis) Drugs Transfusion reaction |
|
Travel to areas where an infection is common (endemic areas) |
Disorders that cause diarrhea Fungal infections such as coccidioidomycosis, blastomycosis, or histoplasmosis Rickettsial infections (such as African tick-bite fever and Mediterranean spotted fever) |
Exposure to insects or animals that carry disease-causing organisms, called vectors (in the United States) |
Ticks: Rickettsiosis, ehrlichiosis or anaplasmosis, Lyme disease, babesiosis, relapsing fever, or tularemia Mosquitoes: Encephalitis caused by arboviruses, malaria, or Zika virus infection Wild animals: Tularemia, rabies, or hantavirus infection Fleas: Plague Domestic animals: Brucellosis, cat-scratch disease, Q fever, or toxoplasmosis Birds: Psittacosis Reptiles: Salmonella infection Bats: Rabies or histoplasmosis |
A weakened immune system (immunocompromise) |
Bacteria: Infection due to pneumococci, meningococci, Staphylococcus aureus, Pseudomonas aeruginosa, Nocardia, or mycobacteria Fungi: Infection due to Candida, Aspergillus, Histoplasma, Coccidioides, microsporidia, Pneumocystis jirovecii, or fungi that cause mucormycosis Parasites: Infection due to Toxoplasma gondii, Strongyloides stercoralis, Cryptosporidium, or Cystoisospora belli |
Drugs that can increase heat production |
Phencyclidine (PCP) Methylenedioxymethamphetamine (MDMA, or Ecstasy) Anesthetics |
Drugs that can trigger fever |
Beta-lactam antibiotics (such as penicillin) Sulfa drugs Phenytoin Carbamazepine Procainamide Quinidine Amphotericin B Interferons (drugs that are based on substances produced by the immune system and that help block the reproduction of viruses) |