Anthrax outbreaks: a warning for improved prevention, control and heightened awareness

A nthrax is a zoonotic disease caused by the gram-positive spore-forming bacterium Bacillus anthracis. It primarily affects domestic and wild herbivores (such as cattle, sheep, goats, bison, deer, antelope and hippos) and in those species it is usually fatal. It is distributed globally and remains enzootic in many regions of the world, particularly sub-Saharan Africa, Asia and Central and South America (World Health Organization (WHO), 2008). The overall disease burden and economic impact of anthrax in livestock is not fully known; however, epizootics occur every year, resulting in the deaths of hundreds to thousands of animals, and disease transmission to humans. Humans are most often infected from exposure to infected animals or their products such as meat, animal hides, bones and other materials. It is estimated that there are 2 000 to 20 000 human anthrax cases occurring annually worldwide (Martin, 2010). A cluster of anthrax outbreaks was reported in July 2016, occurring in reindeer in the Yamal-Nenets Autonomous Okrug, a district of the Russian Federation, with over 2 600 animals reported infected, and with human cases resulting from exposure to the infected animals (Figure 1). Prior to this event, there had been no anthrax outbreaks reported in the affected region since 1941 (Organisation for Animal Health (OIE), 2016a). This outbreak is one of several that have been reported in 2016 from various countries in different regions of the world (Figure 2). Some of these outbreaks have occurred in countries where anthrax has not been reported in recent history. These newly reported outbreaks raise concerns that anthrax may be re-emerging in those areas, potentially linked to changing climatic conditions which may favour the occurrence of the disease. Likewise, there are multiple new or continuing anthrax outbreaks that have been reported from countries worldwide where the disease occurs with regularity. The recurrence of anthrax outbreaks in many parts of the world warrants more attention for heightened awareness and effective control measures to prevent anthrax infection in animals and limit its transmission to humans. It is necessary in an endemic country, or any region that may have conditions conducive to anthrax outbreaks or a history of outbreaks, to maintain vigilance to prevent, detect and respond to outbreaks in those regions, as they may recur in those areas after an absence of several years or more. The infectious cycle of anthrax