Description:

This illustration depicts Bacillus anthracis taken from the peritoneum using a Hiss capsule stain.

Anthrax is diagnosed by isolating B. anthracis from the blood, skin lesions, or respiratory secretions, or by measuring specific antibodies in the blood of persons suspected of having been infected.

Content Provider:

CDC

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

A photomicrograph of Clostridium botulinum bacteria.

This is a photomicrograph of Clostridium botulinum stained with Gentian violet. The bacterium C. botulinum produces a nerve toxin, which causes the rare, but serious paralytic illness Botulism.

Content Provider:

CDC

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

A photomicrograph of the bacterium Brucella melitensis, initially named Micrococcus melitensis.

This is a photomicrograph of Brucella melitensis, the cause of Brucellosis. Symptoms are similar to flu and may also include severe infections of the central nervous systems, and the lining of the heart, or endocardium.

Content Providers(s):

CDC

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This Gram-stain depicts flagellated Vibrio comma bacteria, a strain of V. cholerae; the cause of Asiatic cholera.

A person may get cholera by drinking water or eating food contaminated with the cholera bacterium, therefore, inadequate sewerage treatment can facilitate the spread of the disease during epidemics.

Content Providers:

CDC

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This micrograph of a direct fecal smear is stained to detect Cryptosporidium sp., an intracellular protozoan parasite.

Using a modified cold Kinyoun acid-fast staining technique, and under an oil immersion lens the Cryptosporidium sp. oocysts, which are acid-fast stain red, and the yeast cells, which are not acid-fast stain green.

Content Provider:

CDC

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This colorized transmission electron micrograph (TEM) depicts a salivary gland that had been extracted from a mosquito, which was infected by the Eastern equine encephalitis (EEE) virus, which has been colorized red; magnified 83,900x.

The Eastern equine encephalitis (EEE) virus is a member of the family Togaviridae, and genus Alphavirus. EEE is a mosquito-borne viral disease. As the name suggests, it occurs in the eastern half of the US. Due to the high case fatality rate, it is regarded as one of the more serious mosquito-borne diseases in the United States. This virus is transmitted to humans through the bite of an infected mosquito. The main transmission cycle is between birds and mosquitoes. Several species of mosquitoes can become infected with the EEE virus. The most important mosquito in maintaining the enzootic (animal-based, in this case bird-mosquito-bird) transmission cycle is Culiseta melanura. Horses can become infected with, and die from EEE virus infection.

Content Providers:

CDC/ Fred Murphy; Sylvia Whitfield

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

Ebola virus antigen in skin

Immunohistochemical demonstration of Ebola virus antigen in skin. Histopathology.

Content Providers(s):

CDC/Dr. Sherif R. Zaki

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

After 24 hours, this inoculated MacConkey agar culture plate cultivated colonial growth of Gram-negative Escherichia coli bacteria.

Normally, E. coli serves a useful function in the body by suppressing the growth of harmful bacterial species, and by synthesizing appreciable amounts of vitamins. A minority of E. coli strains are capable of causing human illness by several different mechanisms. E. coli serotype O157:H7 is a rare variety of E. coli that produces large quantities of one or more related, potent toxins that cause severe damage to the lining of the intestine. These toxins [verotoxin (VT), shiga-like toxin] are closely related, or identical to the toxin produced by Shigella dysenteriae.

Content Provider:

CDC

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This photomicrograph reveals Clostridium perfringens grown in Schaedler’s broth using Gram-stain.

Clostridium perfringens is a spore-forming, heat-resistant bacterium that can cause food-borne disease. The spores persist in the environment, and often contaminate raw food materials. These bacteria are found in mammalian feces, and soil.

Content Providers:

CDC/Don Stalons

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

Burkholderia pseudomallei grown on sheep blood agar for 72 hours.

Burkholderia pseudomallei is a Gram-negative aerobic bacteria, and is the causative agent of melioidosis. The organism's colonial morphology changes somewhat as the incubation is extended.

Content Providers:

CDC/Courtesy of Larry Stauffer, Oregon State Public Health Laboratory

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This micrograph depicts an atypical enlarged lymphocyte found in the blood smear from a HPS patient.

Hematologic findings are important in HPS. The large atypical lymphocyte shown here is an example of one of the laboratory findings, which when combined with a bandemia. and dropping platelet count is characteristic of HPS.

Content Provider:

CDC

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This transmission electron micrograph (TEM) depicted numbers of Lassa virus virions adjacent to some cell debris. The virus, a member of the virus family Arenaviridae, is a single-stranded RNA virus, and is zoonotic, or animal-borne that can be transmitted to humans.

There are a number of ways in which the virus may be transmitted, or spread, to humans. The Mastomys rodents shed the virus in urine and droppings. Therefore, the virus can be transmitted through direct contact with these materials, through touching objects or eating food contaminated with these materials, or through cuts or sores. Because Mastomys rodents often live in and around homes and scavenge on human food remains or poorly stored food, transmission of this sort is common. Contact with the virus also may occur when a person inhales tiny particles in the air contaminated with rodent excretions. This is called aerosol or airborne transmission. Finally, because Mastomys rodents are sometimes consumed as a food source, infection may occur via direct contact when they are caught and prepared for food.

Content Providers:

CDC/ C. S. Goldsmith, P. Rollin, M. Bowen

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This transmission electron micrograph (TEM), photographed at the Centers for Disease Control in Atlanta, Georgia, confirmed the suspicion that the 1975 Rhodesian (now Zimbabwean) hemorrhagic fever patient had indeed acquired the Marburg virus while traveling through that country.

Note that in this particular section, the cylindrical Marburg virions were sectioned in various planes, which is why some are seen as longitudinal sections, i.e., lengthwise, while others are seen cut in a transaxial plane, i.e., cross-sectioned, and look circular.

Content Providers:

CDC/ Dr. J. Lyle Conrad

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

Burkholderia pseudomallei grown on sheep blood agar for 48 hours.

Burkholderia pseudomallei is a Gram-negative aerobic bacteria, and is the causative agent of melioidosis. The organism's colonial morphology changes somewhat as the incubation is extended.

Content Providers:

CDC/Courtesy of Larry Stauffer, Oregon State Public Health Laboratory

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This photomicrograph depicts the histopathologic changes in lung tissue in a case of fatal human plague pneumonia; Mag. 160X.

Note the moderate suppurative pneumonia including the presence of many polymorphonuclear leukocytes (PMN), capillary engorgement, and intraalveolar debris, all indicative of an acute infection. H&E stain was used to process this slide.

Content Providers:

CDC/Dr. Marshal Fox

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This DFA-stained micrograph showed the presence of Chlamydia psittaci bacteria in mouse brain tissue; Mag. 400X.

Direct Fluorescent Antibody (DFA) employs a fluorescently labeled, antigen specific antibody, which attaches itself to the cell membrane bound antigen on the Chlamydia psittaci bacteria, and fluoresces under ultraviolet light microscopy.

Content Providers:

CDC/ Dr. Vester Lewis

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

Coxiella burnetii is a species of intracellular, pathogenic bacteria, and is the causative agent of Q fever. The genus Coxiella is morphologically similar to the rickettsia, but with a variety of genetic and physiological differences. C. burnetii are small Gram negative bacteria with two growth phases, as well as a spore form which lies idle in soil.  It can survive standard disinfectants, and is resistant to many other environmental changes.

Content Providers:

Rocky Mountain Laboratories, NIAID, NIH

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

Ricin is a potent toxin that has potential to be used as an agent of biological warfare and as a weapon of mass destruction (WMD). Ricin is widely available, easily produced, and derived from the beans of the castor plant (Ricinus communis).  Ricin can be extracted from castor beans and is known to have an average lethal dose in humans of 0.2 milligrams (1/5,000th of a gram), though some sources give higher figures.  The 2007 Guinness World Records Book considers ricin the world's most potent plant toxin.

Content Providers(s):

USDA

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This photograph depicts the colonial growth pattern displayed by Salmonella typhimurium bacteria cultured on a Hektoen enteric (HE) agar medium; S. typhimurium colonies grown on HE agar are blue-green in color, for this organism is a lactose non-fermenter, but it does produce hydrogen sulfide, (H₂S), therefore there can be black-colored deposits present.

HE agar is the medium designed for the isolation and recovery of fecal bacteria belonging to the family, Enterbacteriaceae.S. typhimurium causes 25% of the 1.4 million Salmonellosis infections a year in the United States. Most persons infected with Salmonella sp. develop diarrhea, fever, and abdominal cramps 12 - 72 hours after infection. The illness usually lasts 4 - 7 days, and most people recover without treatment. However, in some cases, the diarrhea may be so severe that the patient needs to be hospitalized.

Content Providers(s):

CDC

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This photograph depicts the colonial morphology displayed by Gram-negative Shigella boydii bacteria on a blood agar plate (BAP).

Four species from the genus Shigella, S. boydii, S. dysenteriae, S. flexneri, and S. sonnei, are the etiologic agents of the bacterial infection, shigellosis. Most who are infected with Shigella spp. develop diarrhea, which is often bloody, fever, and stomach cramps starting a day or two after they are exposed to the bacterium. Shigellosis usually resolves in 5 to 7 days.

Content Providers(s):

CDC

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

Close-up of smallpox pustules found on the thigh of a patient during the sixth day of the rash.

The smallpox lesions, or pustules, will eventually form scabs that will fall off leaving marks on the skin. The patient is contagious to others until all of the scabs have fallen off.

Content Providers:

CDC/Dr. Paul B. Dean

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

Francisella tularensis, Colonization on Cysteine Heart Agar after 72 hours.

F. tularensis, Colony Characteristics when grown on Cysteine Heart Agar, colonies 2-4 mm, smooth, entire, greenish-white, butyrous with opalescent sheen at 48-72hrs.

Content Providers:

CDC/ Courtesy of Larry Stauffer, Oregon State Public Health Laboratory

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This Gram-negative, intracellular bacteria is quite small and, in addition, it is responsible for causing the disease typhus, which is called classic, European, or epidemic typhus. This bacteria that attacks only humans is spread by the body louse, or occasionally the head louse, and it is usually worst in areas of crowding, poverty, or bad sanitation. The bacteria, which has a short generation time of about ten hours, is first picked up by the louse from a human blood that it consumed. The bacteria enter the digestive system of the louse, and they begin to replicate, which allows the louse to spread the disease to other humans. The bacteria enters the body through the feces or the vomit of the louse, or if a crushed louse is able to get into the skin. Eventually the bacteria in the digestive system of the louse becomes so numerous, that in about ten days the louse itself dies.

Content Providers:

CDC

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This photomicrograph of mouse brain tissue after dying of Venezuelan Encephalitis reveals neural necrosis and edema.

First recognized in the 1930s, Venezuelan Encephalitis has been responsible for numerous outbreaks of febrile illnesses and encephalitis involving thousands of humans and hundreds of thousands of equines, primarily in tropical America.

Content Providers:

CDC/Dr. F. A. Murphy

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

The virus that causes western equine encephalitis has a complex life cycle involving birds and a specific type of mosquito, Culex tarsalis, that is common in farming areas and around irrigated fields. Humans, horses, and other mammals are not an important part of the life cycle of the virus. In rare cases, however, people who live in or visit an area where the virus lives can be infected by the bite of an infected mosquito. Horses are common in these regions and can also be infected. After infection, the virus invades the central nervous system, including the spinal cord and brain. 

Infection can cause a range of illnesses, from no symptoms to fatal disease. People with mild illness often have only a headache and sometimes fever. People with more severe disease can have sudden high fever, headache, drowsiness, irritability, nausea, and vomiting, followed by confusion, weakness, and coma. Young infants often suffer seizures.

Content Providers:

CDC/Dr. F. A. Murphy

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.

Description:

This photograph depicted a close-up view of a Culex tarsalis mosquito as it was about to begin feeding, after having landed on the skin of what will become its human host. Note the light-colored band wrapped around its dark-scaled proboscis (A), and the multiple similarly light-colored bands wrapped around its distal appendages, i.e., the tibia and femur, of its forelegs and middle pair of legs (B), identifying this as C. tarsalis.

Other identifying characteristics include the presence of two silver dots on its dorsal scutum, however, in this particular image, only one of the two bilateral silver scutal marks is visible (C), and a blunted distal abdominal tip, which is not visible in this view. The epidemiologic importance of C. tarsalis lies in its ability to spread Western Equine Encephalitis (WEE), St. Louis Encephalitis (SLE), and California Encephalitis, and is currently the main vector of West Nile virus in the Western United States.

Content Provider:

CDC

Copyright Restrictions:

None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.