The reemergence of glanders as a zoonotic and occupational infection in Iran and neighboring countries

Glanders is a zoonotic infection, and because of recent outbreaks among Equidae family, the possibility of its reemergence among human populations is a crisis. The causative agent is Burkholderia mallei, a Gram-negative, aerobic and highly contagious bacterium causing severe impacts with low infectious dose transmitted via direct contact to respiratory secretions, skin exudates of animals and fomite. Despite high mortality rate, no proper vaccination has been developed to hinder the infection spread. The disease is more prevalent in Australia and Southeast Asia, but has been eradicated in developed countries. Glanders’ clinical signs include pulmonary and disseminated infection depending upon type of infection. Recent reports and outbreaks from Iran and neighboring countries among horses in 2011 and 2017 (Pakistan, Afghanistan and Kuwait), mules in 2008, 2011 and 2017 (Pakistan and Turkey), donkeys and horses in 2011–2015 (Pakistan) and tiger and camels in 2011 (Iran and Bahrain) is a concern. Animal importation or exportation; particularly by healthy carriers is a key route of B. mallei spread. Thus, infection control strategies, accurate and screening before animals’ import, prevention of animal contacts and development of prompt diagnostic approaches and proper therapeutic strategies are essential. Different forms of glanders have emerged or re-emerged in various animals. The factors leading to the re-emergence of the infection mostly include no specific symptoms and anti-B. mallei antibodies, lack of early diagnosis and vaccination strategies, housing conditions, contact with infected and carrier animals and low infectious dose. Sporadic and endemic remote cases have remained in Asia and Middle Eastern countries. Control strategies should focus on surveillance; identify healthy carriers, quarantine and elimination of all infected animals.