Previously we focused on the microbiology and the pathogenesis of Bacillus anthracis, but today we will focus on the epidemiology of the bacteria.
Classification of Anthrax in humans can be classified by the spore entry into the host. Anthrax acquired via break in the skin is termed as cutaneous, eating contaminated meat is termed as gastrointestinal and inhaling spores causes inhalation anthrax. (Cendrowski, S. et al, 2004)
Cutaneous anthrax develops a day to 7 days after exposure, it is relatively less dangerous and prevalent. Gastrointestinal anthrax has an incubation period of 1-7 days and is rare in the United States. Inhalation anthrax is the deadliest types with an incubation period of 7-28 days. (CDC, 2014)
Fig 1-Transmission of anthrax.https://www.brainkart.com/article/Epidemiology—Bacillus-anthracis_18070/
The chance of transmitting Anthrax from one person acting as an intermediate fomites to another person is rare and might result in cutaneous form of anthrax. B. anthracis spores maintain their viability in calcium rich soil with at high pH hence highly infectious to their host. Alkaline soil at a temperature of 15.5 °C with high level of moisture and organic matter promotes the vegetative form of the bacteria, which subsequently increase the production of spores. These conditions can affect outbreak of infection. (Dragon & Rennie, 1995)
B. anthracis is found in the soil hence herbivores are vulnerable to anthrax. Anthrax is enzootic in the southern states of India and 1612 outbreaks were reported between 1991 to 1996.Other enzootic cases of anthrax were reported in China, Nepal, Australia, Namibia and South Africa. The zoonotic nature of Anthrax also makes farmers and people handling animal products susceptible to the infection.In 1957, a Plant that processes goat hair in Manchester in the US was hit with an anthrax outbreak which resulted in 9 cases and 4 fatalities. (Hinton, 1999)
B. anthracis can be used as a biological weapon by the deliberate release of anthrax spores. Anthrax spores are targeted for bioterrorism because, the spores are ubiquitous, tasteless, microscopic and are dispersed without detection. In 2001, mailed letter were contaminated with B. anthracis, 22 people were infected, lead to 5 fatalities. (CDC, 2014) The Infectious dose(ID50) of anthrax in humans ranges from 1000-10,000. B. anthracis have monomorphic strains have identical phenotype and genotype ,based on their location of their habitat.Hence the source of the anthrax used for an attack can be determined. (WHO, 2008)
Anthrax can be prevented with antibiotics, Ciprofloxacinand doxycycline or Anthrax Vaccine Adsorbed (AVA). Infections can also be treated antibiotics and antitoxins. (CDC, 2014)
It has been a remarkable journey, hope you enjoyed yourself as much I did. Thanks for indulging me.
Reference
- Centers for Disease Control and Prevention,(2014) National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)
- Dragon, D. C., & Rennie, R. P. (1995). The ecology of anthrax spores: tough but not invincible. The Canadian veterinary journal = La revue veterinaire canadienne, 36(5), 295–301.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1686874/
- Hinton MH (1999) Infections and intoxications associated with animal feed and forage which may present a hazard to human health. Vet J. 2000; 159:124–138. [Google Scholar]
- World Health Organization (2008)Anthrax in humans and animals – 4th ed. All rights reserved. Publications of the World health organization. Who Press, World health organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland
Hello!
Great blog post! The first time I heard about Anthrax was actually in my biosafety class. One of the things I found shocking as you mentioned in your blog post is how Anthrax was used as a biological weapon to kill many people. That is crazy!! Also, its crazy to think that because Anthrax is zoonotic, the spores can easily get into the food that we eat which can cause several detrimental issues in the food and agricultural industries .
-Simi P.
I had no idea that Anthrax was a zoonotic pathogen! Are goats the only carriers of this infection or is it other farm animals as well? I vaguely remember hearing about the anthrax scare in the early 2000s but I was too young to understand what this deadly pathogen was capable of. It is comforting to know that Anthrax is not as much of a natural threat in the U.S. Thank you for the information!
I thought that Anthrax was a bacteria that only existed because of 9/11 and bioterrism. It’s nice that you did a blog explaining Anthrax and its uses outside of bioterrism and how it reproduces and can be found in meats and in the soil. I think it was also interesting that Anthrax that is not inhaled causes cutaneous infection because I thought it only infected its host through the air.
I really love the layout of your page! I was learning about this disease in my biosafety and principles class and the history about this disease is so cool as well as the extra precautions that you have to take when working with it in the lab.