New Delhi (CNN)Three people in the southern Indian state of Kerala have died of the Nipah virus.
Two brothers in their late 20s and their aunt, 50, died from the virus in Kozikhode district, according to Dr. Reena KJ, the state's assistant director of public health.
The father of the two men, 56, is currently on life support and in a "delirious state," said Reena.
The virus, which can be spread by contact with animals or humans, can develop from headache and drowsiness to a coma within days, according to the US Centers for Disease Control and Prevention. Treatment is limited to supportive care.
The first death was reported Saturday, after which the country's health ministry and the World Health Organization were contacted, the office of Kerala chief minister, Pinarayi Vijayan, wrote in a tweet Monday.
A statewide alert has been given to remain vigilant and a 24-hour control room opened, added Vijayan.
Fluid samples have been taken from 14 people who visited the deceased in the hospital, along with 27 members of hospital staff who had come into contact with them during their treatment, according to Reena.
She added that deaths in other districts where people presented with the symptoms of the Nipah are also being tested, Reena said.
India's Health Ministry has deployed a response team to Kerala.
The country's union minister of health and family welfare, JP Nadda, said in a statement that his department was "closely monitoring the situation" and has "dispatched a Central team to assist the State government and initiate required steps."
The state government has made assurances that the "health department is doing everything possible to save the lives of the infected and prevent the advance of virus."
A subsequent tweet urged private hospitals to "not deny treatment for anyone suffering from fever."
About Nipah virus
The Nipah virus can cause a range of symptoms in those infected, including fever, headache, confusion and disorientation. More severe symptoms include acute respiratory syndrome -- where the lungs cannot get enough oxygen to the body -- and fatal encephalitis, an inflammation of the brain.
The virus is known to infect both humans and animals, with certain species of fruit bat being natural hosts. People can become infected after contact with infected bats, pigs or humans.
There is no vaccine against Nipah and the only treatment option is supportive care, according to WHO.
Nipah virus was first identified during a 1998-1999 outbreak in Malaysia, where almost 300 people were infected and more than 100 died, according to the CDC. More than a million pigs were euthanized to halt the spread of the illness. The virus was named after the village of Kampung Sungai Nipah, where pig farmers contracted the disease.
There have been subsequent outbreaks in India and Bangladesh, with more than 600 reported human cases between 1998 and 2015, according to the WHO. Many parts of Asia, as well as Australia, Madagscar and Ghana are at risk of outbreaks.
The virus is on the WHO's list of epidemic threats in need of urgent research and development.