In late December 2015, new cases of Kyasanur Forest disease (KFD), or monkey fever, occurred in the Mauxi region of the Thane village panchayat in southwestern India, according to the Indian newspaper The Navhind Times. So far 2 people have been confirmed to have the tick-borne viral disease in the Mauxi village and have been referred to the Goa Medical College at Bambolim for further treatment. In February 2015, there was an outbreak of the disease in Pali village, affecting over 50 people and killing five. Both patients are “now in good condition,” according to Surekha Parulekar, a health officer at the Valpoi Community Health Centre.
KFD is not new to India. The disease was first reported from the Kyasanur Forest in the eastern foothills of the Western Ghats in the then-named Mysore State in southern India. The virus was first isolated from the blood of a monkey found dead in the forest and was later determined to be spread by the bite of a type of tick called Haemaphysalis spingera. This tick is wildly disturbed in the tropical forests of peninsular India and neighboring Sri Lanka. The disease is endemic in several of the southwestern states of India, including Kerala, Kernataka, Tamil Nadu, and Goa, but since 2012, it has been reported in new areas beyond this core endemic region. On average, there have been 400-500 cases of KFD in India every year since 1957. Infected individuals experience high fever, chills, severe headache, sensitivity to light, and often diarrhea, vomiting, and bleeding of the gums, nose, and gastrointestinal bleeding. In this regard, KFD is considered a “hemorrhagic fever,” similar to its more famous relative, Ebola. Because there is no specific treatment for KFD, the mortality rate has been reported to be 4-15%, greatly depending on the level of supportive care the patients receive.
Tick surveillance and control is key to preventing future outbreaks of the disease. “The only strategy that can be adopted to guard against KFD outbreaks would be a regular surveillance for ticks and testing them for virus positivity,” said Parulekar in the article. In addition, a monkey’s death in a locality is often an indication that human infections may follow. So people should be observant for sick or dead monkeys and report them immediately to public health officials. As an encouraging sign, a new virology centre at the Community Health Centre at Valpoi has started studies investigating KFD and other viruses in the area.
However, as long as people are exposed to infected ticks, KFD will likely continue to be a public health threat in southern India.
Chris A. Whitehouse is a microbiologist and science writer who lives in Maryland. He writes extensively on emerging infectious diseases of humans and animals.