The death of 53 tribals in Bijapur district and 12 tribals in Dantewada district took place during the monsoon months of June and July.
"All deaths were caused due to water-borne diseases as residents of interior pockets had no option but to use water of culvert for drinking after they were marooned by monsoon rain in June and July," S.M. Murty, a senior official at the directorate of health services here, told IANS.
Doctors' teams visited the affected region soon after several deaths were reported and collected samples to ascertain the nature of disease, officials added.
Murty said a total of 10 samples were collected from Bijapur in June and July of which one was confirmed as cholera.Five samples were tested at Raipur Medical College of which four were negative while one was confirmed as cholera. Five other samples were sent to Kolkata-based National Institute of Cholera and Enteric Diseases (NICED).
"The NICED officials informed us on telephone in late September that all the five samples sent by us were negative but we have asked them to send the finding in writing," Murty added.
Bijapur and Dantewada districts are part of the 40,000 sq km Bastar region which also includes Bastar, Narayanpur and Kanker districts. The region is considered as one of the most poverty-hit areas of the country.
Officials said that residents of tribal-dominated Bijapur and Dantewada districts still travel several kilometres in forests on foot to access medical facilities at primary health centres.