Types of Infectious Agents and the Diseases Caused by Them
Types of Infectious Agents
- Bacteria
- Fungi
- Protozoa
- Virus
Bacteria
- Bacillus anthracis: Anthrax (cutaneous, gastrointestinal, inhalational).
- Chlamydia trachomatis: Trachoma, neonatal conjunctivitis and pneumonia, urethritis, cervicitis, salpingitis, lymphogranuloma venereum.
- Chlamydophila pneumoniae: Pneumonia.
- Chlamydophila psittaci: Pneumonia.
- Clostridium botulinum: Botulism: foodborne, infant, wound.
- Clostridium difficile: Antibiotic-associated diarrhea, pseudomembranous colitis.
- Clostridium perfringens: Soft tissue infections (cellulitis, fasciitis, myonecrosis or gas gangrene); food poisoning; septicemia.
- Clostridium tetani: Tetanus.
- Corynebacterium diphtheriae: Diphtheria, cutaneous (wound) diphtheria.
- Ehrlichia chaffeensis: Human monocytic ehrlichiosis.
- Listeria monocytogenes: Neonatal disease (meningitis, septicemia); spontaneous abortion or preterm delivery; flu-like illness; bacteremia or meningitis in patients with immunodeficiency.
- Mycobacterium leprae: Leprosy.
- Mycobacterium tuberculosis: Tuberculosis (pulmonary, extrapulmonary).
- Mycoplasma pneumoniae: Atypical pneumonia (walking pneumonia).
- Neisseria gonorrhoeae: Gonorrhea, pelvic inflammatory disease, septic arthritis, ophthalmia neonatorum.
- Neisseria meningitidis: Meningitis, meningococcemia.
- Bordetella pertussis: Pertussis (whooping cough).
- Campylobacter jejuni: Gastroenteritis.
- Escherichia coli— enteroaggregative (EAggEC): Diarrhea with mucus.
- E. coli—enterohemorrhagic (EHEC): Watery diarrhea, hemorrhagic colitis, uremic syndrome.
- E. coli—enteroinvasive (EIEC): Watery diarrhea, hemorrhagic colitis.
- E. coli—enterotoxigenic (ETEC): Watery diarrhea.
- E. coli—meningitis associated: Acute meningitis (neonates).
- E. coli—uropathogenic: Cystitis, pyelonephritis.
- E. coli—enteropathogenic (EPEC): Watery diarrhea and vomiting.
- Francisella tularensis: Tularemia.
- Haemophilus influenzae: Meningitis, septicemia, epiglottitis, otitis media, sinusitis, bronchitis, pneumonia.
- Helicobacter pylori: Gastritis, peptic and duodenal ulcers, gastric cancer.
- Legionella pneumophila: Legionnaire disease (pneumonia), Pontiac fever (flu-like illness).
- Pseudomonas aeruginosa: Skin infections, urinary tract infections, ear or eye infections, bacteremia, pulmonary infections (cystic fibrosis).
- Rickettsia rickettsii: Rocky Mountain spotted fever.
- Salmonella enterica: Diarrhea, enteric (typhoid) fever (ssp., typhi).
- Shigella species: Bacillary dysentery.
- Staphylococcus aureus: Cutaneous infections (impetigo, folliculitis, furuncles, carbuncles); disseminated infections (pneumonia, osteomyelitis, endocarditis, septic arthritis); toxin-mediated diseases (toxic shock syndrome, food poisoning); community acquired infections.
- Staphylococcus species (coagulase negative): Opportunistic infections; infections of foreign bodies (catheters, shunts, prosthetic joints, heart valves).
- Streptococcus agalactiae (group B): Neonatal disease (bacteremia, pneumonia, meningitis).
- Streptococcus pneumoniae: Pneumonia, meningitis, endocarditis, bacteremia.
- Streptococcus pyogenes (group A streptococci [GAS]): Pharyngitis; scarlet fever; sinusitis; skin and soft tissue infections (impetigo, erysipelas, cellulitis, necrotizing fasciitis); toxic shock syndrome; rheumatic fever; glomerulonephritis.
- Vibrio cholerae: Severe watery diarrhea.
- Yersinia pestis: Bubonic and pneumonic plague.
Fungi
- Aspergillus species: Mycotoxicosis (bleeding), allergic bronchopulmonary aspergillosis, pneumonia, organ abscesses (opportunistic mycosis).
- Blastomyces dermatitidis: Asymptomatic pulmonary infection, chronic skin and bone infections.
- Candida albicans: Oral thrush, vaginitis, chronic mucocutaneous candidiasis, systemic infections (opportunistic mycosis).
- Cryptococcus neoformans: Pulmonary masses, chronic meningitis, cerebral masses, systemic spread (usually in immunocompromised patients).
- Epidermophyton species, Microsporum species, Trichophyton species: Dermatophytoses (tinea).
- Histoplasma capsulatum: Latent infections, acute pulmonary histoplasmosis, disseminated histoplasmosis.
- Pneumocystis jirovecii: Pneumocystis pneumonia (PCP) especially in AIDS patients.
Protozoa
- Entamoeba histolytica: Asymptomatic infection, intestinal amebiasis (colitis with diarrhea), amebic liver abscess.
- Giardia lamblia: Asymptomatic infection, acute watery diarrhea, chronic intermittent diarrhea with malabsorption.
- Plasmodium species: Malaria.
- Toxoplasma gondii: Asymptomatic infection; spontaneous abortion stillbirth or severe neonatal disease (epilepsy, encephalitis, chorioretinitis, hydrocephalus).
- Trichomonas vaginalis: Asymptomatic infection, vaginitis.
- Trypanosoma brucei: African sleeping sickness.
Viruses
- Adenoviridae: Acute respiratory disease, pneumonia, conjunctivitis, gastroenteritis.
- Arenaviridae: Hemorrhagic fever.
- Coronaviridae: Common cold
- Hepadnaviridae: Hepatitis B (serum hepatitis), primary hepatocellular carcinoma.
- Herpesviridae: Fever blisters, cold sores, genital lesions.
- Papillomaviridae: Skin warts, mucosal papillomas, anogenital warts, cervical cancer (certain HPV types).
- Polyomaviridae: Progressive multifocal leukoencephalopathy (immunocompromised patients).
- Poxviridae: Smallpox, Molluscum skin lesions.
- Parvoviridae: Erythema infectiosum (fifth disease), fetal anemia.
- Paramyxoviridae: Cold-like illness, bronchitis, croup.
- Orthomyxoviridae: Classic flu, severe respiratory tract infection.
- Rhabdoviridae: Rabies.
- Filoviridae: Hemorrhagic fever.
- Bunyaviridae: Febrile illness, rash, encephalitis.
- Retroviridae: AIDS.
- Togaviridae: Rubella (German measles), congenital defects.
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