Getting a Handle on Glanders

In this excerpt from Equine Disease Quarterly, a researcher from Dubai discusses the steps being taken to contain and control the spread of glanders, a dangerous bacterial infection in horses.

Glanders, caused by Burkholderia mallei, is a highly contagious bacterial disease in equids and is widely regarded as a very important zoonosis (a disease that can be transmitted from animals to humans). It is notifiable to the World Organization of Animal Health (OIE, in Paris, France). The disease is still endemic in various parts of the world, including but not exclusive to, the Middle East, Asia, and South America. The occurrence and distribution of glanders in Africa is unknown. Glanders has reemerged in Brazil, Pakistan, India, and Turkey, and outbreaks have been reported in Iraq, Iran, Mongolia, and China. In more recent years, glanders has been recorded in the United Arab Emirates (UAE), Kuwait, and Bahrain, but it has never been reported in the United States.

Glanders was detected for the first time in the UAE in 2004, occurring in an official UAE quarantine facility in Dubai. The OIE was notified immediately, and veterinarians were able to control and eliminate the infection by euthanizing 75 affected horses. A total of 10 glanders-positive horses were identified in a shipment that originated in Syria. This finding resulted in a total embargo on the movement of horses from Syria into Dubai. Research that followed the glanders outbreak in Dubai resulted in the adoption of serological tests in addition to the complement-fixation test (CFT) recommended by the OIE. The OIE then designated the Central Veterinary Research Laboratory (CVRL) in Dubai as an OIE reference laboratory for glanders.

Despite the export of glanders-positive horses to Dubai, horses continue to be exported from Syria to other Gulf Cooperation Council (GCC) countries. Some years ago, ministers of the countries involved agreed to prevent horses with notifiable diseases from entering any other GCC States. The CVRL would conduct all glanders testing.

Between 2009 and 2010 more than 30 horses traveling to Kuwait tested positive for glanders via the CFT. These findings were reported to the OIE, the appropriate regulatory authorities in Kuwait, and the UAE. These results provided additional justification for the UAE not to lift the ban on importing horses from either Syria or Kuwait.

At the end of 2010 the first glanders-positive horse in Bahrain was reported. The diagnosis was confirmed by the CVRL , and the European Union was informed of the result. Later, Kuwait and Bahrain notified occurrence of the disease to the OIE. Bahranians subsequently requested help from CVRL experts. On several occasions, necropsies were performed on numerous glanderous horses in Bahrain, and several isolations of the pathogen were made. During one of the visits (to Bahrain), researchers determined that the disease had spread to dromedary camels. Molecular biological investigations carried out in Munich confirmed that the bacteria isolated from the dromedary were similar to an isolate cultured from Dubai in 2004. In the course of these investigations, researchers found that a stallion necropsied in Bahrain with severe signs and glanders lesions had tested CFT positive in Kuwait eight months previously. No further information was available on this particular case.

In Bahrain, where the CVRL tested in excess of 4,000 horses, more than 50 horses affected with glanders were identified and euthanized. A second round of testing is under way, and already several horses have been found positive, with classical clinical signs and glanders lesions as well as positive serology.

The CVRL has submitted several requests to the OIE and to the European Union to investigate the source(s) of glanders in the Middle East to help restrict further spread of the infection, especially in view of the expanding horse industry in the region. From a scientific point of view, disease events over the past several years have significantly increased our knowledge and concern about glanders and the risk of more global distribution of the disease.

CONTACT: Priv. Doz. Dr. Dr. habil. U. Wernery,, Central Veterinary Research Laboratory, P.O. Box 597, Dubai, United Arab Emirates.

This is an excerpt from Equine Disease Quarterly, funded by underwriters at Lloyd's, London, brokers, and their Kentucky agents.

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