Hundreds of Cutaneous Anthrax Cases in Bangladesh
By Amesh A. Adalja, MD , September 17, 2010
Since August 18, 2010, more than 400 cases of cutaneous anthrax have been reported in Bangladesh. None have been fatal, and all have been linked to infected cattle. This outbreak, which is the largest anthrax outbreak in the nation’s history, has sparked a “red alert,” which calls for health inspectors to search for and cull affected cattle. Although inspections of cattle slaughter houses and culling have commenced, many cattle are slaughtered in private kitchens and butcher shops, where it is not possible to conduct inspections.1-3
Transmission and Disease Progression
Following contact with an infected animal, humans may develop cutaneous anthrax if Bacillus anthracis spores enter abraded skin. Following germination, there is a 2 to 5 day incubation period, after which a skin lesion develops and progresses through the following 3 phases:
appearance of a painless, pruritic papule;
formation of vesicles around the papule; and
ulceration following rupture of vesicles, with the characteristic black eschar, marked edema, and induration (see photograph above).
When treated, cutaneous anthrax is not fatal. However, with systemic spread, the mortality rate for untreated cases is 10% to 20%, which makes early recognition and treatment essential.4
Diagnosis and Treatment
Although many PCR-based modalities exist, diagnosis of cutaneous anthrax is usually by culture of the vesicle fluid or blood.
When drug resistance rates are lower than 10%, as in a naturally occurring outbreak, treatment of choice is 7 to 10 days of penicillin. Other effective antibiotics include doxycycline, levofloxacin, and ciprofloxacin.4
In Bangladesh, animal vaccination programs are being employed to prevent infection in cattle. However, vaccination is not a panacea; spores can adhere to cows’ hair without causing disease, and can be spread to a human handler. Human vaccination for anthrax is efficacious, but requires a series of 5 injections administered over 18 months, plus annual boosters.1-4
The outbreak in Bangladesh—which was preceded by an outbreak in Omsk, Russia, that was linked to horse meat—illustrates the risk of naturally occurring anthrax, which occurs in many parts of the world.5 Fortunately, with prompt recognition and implementation of countermeasures (antibiotics, culling, vaccination, and improved slaughtering practices) such outbreaks are short-lived and do not spread in epidemic fashion. However, vigilance is necessary to diagnose cutaneous anthrax and to pinpoint its source.
479 people confirmed to be infected by anthrax in Bangladesh. Xinhua. http://news.xinhuanet.com/english2010/health/2010-09/09/c_13486954.htm. Accessed September 11, 2010.
Bangladesh anthrax cases spread. BBC. http://www.bbc.co.uk/news/world-south-asia-11194760. Accessed September 11, 2010.
Anthrax, human, equine - Russia: (OM) dumplings. ProMED-mail. http://www.promedmail.org/pls/apex/fp=2400:1202:1738380675793358::NO::F2400_P1202_CHECK_DISPLAY,F2400_P1202_PUB_MAIL_ID:X,83984. Accessed September 11, 2010.
Martin GJ, Friedlander AM. Bacillus anthracis (Anthrax). In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, PA: Churchill Livingstone; 2010:2715-2725.
Anthrax, human, bovine - Bangladesh (14). ProMED-mail. http://www.promedmail.org/pls/apex/fp=2400:1001:6948243366706702::NO::F2400_P1001_BACK_PAGE,F2400_P1001_PUB_MAIL_ID:1010,84753. Accessed September 11, 2010.