The dangerous disease glanders has killed four horses in western India, local media report.
They are the first reported cases of the disease in the state of Maharashta in 11 years, according to local officials.
The Indian Express reports that the cases were in Ahmednagar, Thane, Akola and Satara.
Glanders, which is usually fatal to both animals and humans, is caused by the bacterium Burkholderia mallei. Signs include lung lesions and ulceration of mucous membranes in the respiratory tract. The acute form results in coughing and fever, followed by septicaemia and death within days.
In chronic cases, nodules form on the skin and in the nasal passages, eventually ulcerating. Death can result within months, with those surviving acting as carriers.
The only known reservoirs of B. mallei are single-hooved animals, particularly horses. Chronically infected horses can be asymptomatic but may remain highly infectious.
Glanders has also proved capable of infecting camels, felines living in the wild, bears, wolves and dogs. Carnivores may become infected by eating infected meat. Guinea pigs and hamsters are highly susceptible.
The incubation period varies from a few days to many months depending on the intensity of exposure. Infections generally prove fatal.
Due to its high mortality rate and the small number of organisms needed to establish infection, it is regarded as a potential biological warfare or bioterrorism agent.
Commissioner Kantilal Umap, of the state’s animal husbandry department, confirmed the deaths of four horse to the Express, with the first positive test reported in April, in Ahmednagar. Since then, samples from working animals in Thane, Akola and Satara’s Panchgani have tested positive.
Measures being taken to contain the spread of the disease included increased surveillance of animals within a 5-kilometre radius of the cases.
More than 1500 samples have been collected for testing and a close watch is being kept on the movement of animals, he told the Express.
There is no vaccine against the bacterium and it is resistant to multiple antibiotics.
Although glanders has been eradicated from many Western countries, it recently emerged in Asia, the Middle-East, Africa, and South America.
Due to its rarity, little is known about outbreak dynamics of the disease.
Researchers have warned that the global trade of animals from glanders-endemic regions can re-introduce and possibly re-establish this disease in animal populations of countries that have previously eradicated it.
“The recent emergence of glanders in combination with worldwide horse trading might pose a new risk for human infections,” they said.