This document lists various microbes that can cause disease in humans, their associated diseases, targets in the body, and typical sources or modes of transmission. It covers bacterial, fungal, and parasitic (protozoan and helminth) pathogens. For each microbe, it provides brief details on the disease(s) it causes, the parts of the body it typically infects, and how humans usually become exposed or infected.

2. MICROBES DISEASE TARGET SOURCE / MODE
BACTERIAL PATHOGEN
Streptococcus pyrogenes Streptococcal Upper RT membranes Droplets
Pharyngitis
Viridams streptococci Sinusitis Upper RT and saliva Normal flora
Streptococcus Pneumococcal Lower RT, lungs, Droplets, mucus
pneumoniae oneumonia; otitis media; meninges
sinusitis meningitis
Bacillus anthracis Pulmonary anthrax Upper & lower RT Spore inhaled from
animals / products
Corynebacterium Diphtheria Upper RT membranes; Dropleta
diptheriae also skin
Heamophilus influenzae Pharyngitis Upper RT membranes Droplet
Mycobacterium Tuberculosis Lower RT; lungs Droplets; droplet nuclei
tuberculosis
Nocardia brasiliensis Nocardiosis (a form of Lower RT; lungs Spores inhaled from
pneumonia) environment

3. MICROBES DISEASE TARGET SOURCE / MODE
BACTERIAL PATHOGEN (continuation...)
Legionella pneumophila Legionnaire disease; Lower RT; lungs Aerosol from aquatic
pontiac fever habitats
Brucella Brucellosis (undulant RT Aerosol from infected
fever) animals
Bordetella pertussis Whooping cough Upper & lower RT Droplets
Klabsiella pneumoniae Ooportunisitic Lower RT lungs Droplets,normal flora,
Psuedomonas pneumonias aerosols, fomites
aeruginosa
Yersinia pestis Pneumonic plague Lower RT lungs Droplets, animal aerosols
Mycoplasma Primary atypical Lower RT, lungs Droplets, mucucs
pnuemoniae pnuemonia
Chlamydiophila Chlamydial pneumonitis Lower RT, lungs Droplets, mucus
pnueomoniae

4. MICROBES DISEASE TARGET SOURCE / MODE
BACTERIAL PATHOGEN (Continuation...)
Chlamydiophila psittaci Ornithosis (psittacosis) Lower RT, lungs Arosols, droplets from
birds
Coxiella burnetii Q fever Lower RT, lungs Ticks, aerosols from
animals, dust
PARASITIC (Protozoan, helminth)
Paragonimus westermani Adult lung fluke Lung Tissue; intestine Larvae ingested in raw or
under cooked crustacea

5. MICROBES DISEASE TARGET SOURCE / MODE
FUNGAL PATHOGENS
Histoplasma capsulatum Histoplasmosis Lower RT, lungs Spores inhaled in dust
Blastomyces dermititidis Blastomycosis Lower RT, lungs Spores inhaled
Coccidioides immitis Coccidioidomycosis Lower RT, lungs Spores Inhaled
(Valley Fever)
Cryptococcus Cryptococcosis Lower RT, lungs Yeast inhaled, Can be
neoformans normal flora
Sporothrix schenckii Sporothrix pneumonia Lower RT, lungs Spores on vegetation
Pneumocystis (carinii) Pneumocystis Lower RT, lungs Spores widespread,
jiroveci pneumonia (PCP) normal flora
Aspergillus fumigatus Aspergillosis Lower RT, lungs Spores, widespread in
dust, air

7. MICROBES DISEASE TARGET SOURCE / MODE
Staphyloccus aureus Staph food intoxication Small Intestine Food contaminated by
human carriers
Streptoccus mutans Dental caries Tooth surface Normal flora, saliva
Actinomyces israeli Actinomycosis Oral membranes; Normal flora; enter
cervicofacial area damaged tissue
Escherichia coli Traveler’s diarrhea Small intestine Food, water, rare or raw
O157:H7 enteritis beef
Salmonella typhi Typhoid fever Small intestine Human carriers; food,
drink
Shigella spp. Bacillary dysentery Large intestine Human carriers; food,
flier

8. MICROBES DISEASE TARGET SOURCE / MODE
Yersinia Enterocolitica Yersiniosis Small intestine; A zoonosis; food and
(Gastroenteritis) lymphatics drinking water
Vibrio cholerae Epidemic cholera Small intestine Natural waters; food
contaminated by human
carriers
Helicobacter pylori Gastritis, gastric Esophagus, stomach, Human, cat
intestinal ulcers duodenum
Campylobacter pylori Enteritis Jejunum (segment of the Water, milk, meat, food
small intestine) infection
FUNGAL PATHOGENS
Aspergillus flavus Aflatoxin poisoning Liver Toxin ingested in food
Candida albicans Esophagitis Esophagus Normal flora

9. MICROBES DISEASE TARGET SOURCE / MODE
PARASITIC (PROTOZOAN, HELMINTH)
Entamoeba histolytica Amebic dysentery Caecum, appendis, Food, water-
colon, rectum contaminated fecal cyst
Gardia lambia Gardiasis Duodenum, jejunum Ingested cysts from
animal, human carriers
Balantidium coli Balantidiosis Large Intestine Swine, contaminated
food
Cryptosporidium spp. Cryptosporoidosis Small and large intestine Animals, natural waters,
contaminated food
Toxoplasma gondii Toxoplasmosis Lymph nodes Cats, rodents, domestic
animals
PARASITIC (PROTOZOAN, HELMINTH)
Enterobius vermicularis Pinworm Rectus, anus Eggs ingested from
fingers, food

10. MICROBES DISEASE TARGET SOURCE / MODE
PARASITIC (PROTOZOAN, HELMINTH)
Ascaris lumbricoides Ascariasis Worms burrow into Fecally contaminated
intestinal mucosa food and water
containing eggs
Trichuris trichiura Trichiuriasis, whipworm Worms invade small Food containing eggs
intestine
Trichinella spiralis Trichinosis Larvae penetrate Pork and bear meat
intestine containing encysted
larvae
Necator americanus Hook worms Large and small intestine Larvae deposited by feces
Ancylostoma duodenale into soil; burrow into feet
Fasciola hapatica Sheep liver fluke Large and small intestine Watercrests
Taenia saginata Beef tapeworm
Large intestine; pork Raw or rare beef or
Taenia solium Pork Tapeworm larva can migrate to porkcontaining larval
brain forms