Anthrax: how is anthrax transmitted?

Anthrax or anthrax is a zoonosis caused by Bacillus anthracis bacteria. It mainly affects animals but can be transmitted to humans. There are different forms of anthrax depending on whether it is respiratory, cutaneous or digestive. “It is a very closely monitored disease because it could serve terrorist biological attack. But in realityit is rare in humans. and mainly affects animals” indicates Dr. Benjamin Davido, infectiologist. What are the symptoms? How is it transmitted? What are the treatments to cure it? Is there a vaccine?

What is anthrax?

Anthrax or “anthrax” or “anthrax” is a infectious and contagious zoonosis. It is due to a Gram-positive rod-shaped bacterium, the bacterium “Bacillus anthracis”. It affects mammals, mainly herbivores (cattle, sheep, goats and horses) and some birds. “She can transmit to humans through infected animals or their products (leather or meat)” indicates Dr. Davido, infectiologist. It is recognized as an occupational disease. “In humans, it can take different forms depending on the route of entry of the bacteria.“says the infectiologist.

► The cutaneous form: this is the most common in humans. Skin involvement is caused by contact between the bacteria and a wound.

► Gastrointestinal forms: human digestive contamination is possible when consumption of meat from infected animals that is undercooked.

► The respiratory form: this is the most serious. Contamination occurs by inhaling the spores. “A bit like the Covid, this attack will cause pneumonia because the spores will lodge at the bottom of the alveoli of the lung“explains the expert. It can be fatal but you have to inhale very large quantities of spores.

What causes anthrax?

Anthrax is caused by Bacillus anthracis bacteria. The bacterium is present in soils as a spore that can survive for decades. The spores can rise to the surface and contaminate grass and plants ingested by animals.

What are the symptoms of anthrax?

Symptoms depend on the form of anthrax. “The digestive form is manifested by diarrhea-like gastrointestinal symptoms. Skin involvement creates a ulceration (a digging wound) which will gangrene, become blackish (hence the name of the sickness) and can damage fabrics. The respiratory form causes a flu syndrome followed by severe pneumonia which can be devastating if not treated quickly” details Dr. Davido. The period incubation in humans ranges from one day to over 2 months.

Photo of anthrax

“In the presence of black plaques in patients in contact with animalsthe doctor performs a wound biopsyincluding cultivation and PCR technique allows rapid diagnosis. You should know that in more than 50% of cases, respiratory diseases are not documented, including in the hospital.“Notes Dr. Davido. For the respiratory form, which is very rare, the diagnosis and treatment adapted to pneumonia are carried out. Gastrointestinal anthrax is diagnosed as gastroenteritis.

In animals, infection most often occurs in pasture by grazing contaminated grass. In humans, digestive disease is transmitted by consumption of meat from an infected and undercooked animal. “The cutaneous form is caught when our skin has a wound and comes into contact with that of an infected animal or product of animal origin via a caress or when a craftsman works the wool or the leather of the animal for example” illustrates Dr. Davido. Finally, respiratory contamination occurs through inhalation of airborne bacterial spores.

“Anthrax bacteria are relatively sensitive to fluoroquinolone antibiotics” indicates the infectiologist. Concerning the digestive form, the same antibiotic treatment is prescribed as for infectious diarrhea.

Is anthrax fatal?

“The cutaneous form is not fatal but it gangrenes so it damages the tissues and often requires an operation” emphasizes Dr. Davido. The digestive form is not fatal. “The respiratory form can be when it causes severe pneumonia and is not treated quickly“adds the infectiologist.

Is there a vaccine against anthrax?

There is a vaccine against anthrax, it is the most effective way to limit the spread in animals. “You can also administer a vaccine to humans in case of contact with the bacteria. It is a disease which, unlike viral diseases, has rather easily accessible antibiotics.“ notes the expert.

Thanks to Dr Benjamin Davido, infectious disease specialist.

Sources:

– Guide to Understanding Anthrax, Center for Control and Prevention of Emerging and Zoonotic Infectious Diseases (CDC), August 2016

– Anthrax or anthrax, National Food Safety Agency (Anses), July 2013