Re: Who first discovered Anthrax?

The anthrax bacillus, Bacillus anthracis, was the first bacterium shown to be 
the cause of a disease. In 1877, Robert Koch grew the organism in pure culture, 
demonstrated its ability to form endospores, and produced experimental anthrax 
by injecting it into animals. 


Robert Koch's original micrographs of the anthrax bacillus
Bacillus anthracis is very large, Gram-positive, sporeforming rod, 1 - 1.2µm in 
width x 3 - 5µm in length. The bacterium can be cultivated in ordinary nutrient 
medium under aerobic or anaerobic conditions. Genotypically and phenotypically 
it is very similar to Bacillus cereus, which is found in soil habitats around 
the world, and to Bacillus thuringiensis, the pathogen for larvae of 
Lepidoptera. The three species have the same cellular size and morphology and 
form oval spores located centrally in a nonswollen sporangium. 

Bacillus thuringiensis is distinguished from B. cereus or B. anthracis by its 
pathogenicity for Lepidopteran insects (moths and caterpillars) and by 
production of an intracellular parasporal crystal in association with spore 
formation. The bacteria and protein crystals are sold as "Bt" insecticide, 
which is used for the biological control of certain garden and crop pests. 
 Bacillus cereus is a normal inhabitant of the soil, but it can be regularly 
isolated from foods such as grains and spices.  B. cereuscauses two types of 
food-borne intoxications (as opposed to infections). One type is characterized 
by nausea and vomiting and abdominal cramps and has an incubation period of 1 
to 6 hours. It resembles Staphylococcus aureus food poisoning in its symptoms 
and incubation period. This is the "short-incubation" or emetic form of the 
disease. The second type is manifested primarily by abdominal cramps and 
diarrhea with an incubation period of 8 to 16 hours. Diarrhea may be a small 
volume or profuse and watery. This type is referred to as the "long-incubation" 
or diarrheal form of the disease, and it resembles food poisoning caused by 
Clostridium perfringens.  In either type, the illness usually lasts less than 
24 hours after onset. 
The short-incubation form is caused by a preformed heat-stable enterotoxin of 
molecular weight less than 5,000 daltons. The mechanism and site of action of 
this toxin are unknown. The long-incubation form of illness is mediated by a 
heat-labile enterotoxin (molecular weight of approximately 50,000 daltons) 
which activates intestinal adenylate cyclase and causes intestinal fluid 
secretion. 
http://www.bact.wisc.edu/Bact330/lectureanthrax

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June Wingert
Associate Scientist