Indian wildlife authorities on Sunday attributed all cheetah deaths in the Kuno National Park so far to “natural causes” and said any suggestions that collar-related infections had killed two cheetahs last week were “speculation and hearsay”.

The statement from the National Tiger Conservation Authority (NTCA), the Union environment ministry agency implementing the cheetah introduction project, has surprised sections of wildlife experts, some of whom called it an attempt to “obfuscate” the circumstances of some of the cheetahs’ deaths.

Wildlife veterinarians guiding the project have suggested that two South African male cheetahs had died last week from septicemia (blood poisoning) caused by bacterial infections that had resulted from fly larvae, or maggots, feeding on skin tissues near the cheetahs’ neck collars. The veterinarians suspect that humid or wet weather had caused water to accumulate under the collars, causing inflammation and drawing the flies.

Veterinarians in Kuno who have examined some of the other cheetahs over the past two days have detected similar neck-related irritation near the collars in two other cheetahs, a veterinarian familiar with the outcome of the examinations said.

But the NTCA statement, released by the environment ministry on Sunday, appeared to challenge the collars-and-flies angle. “Such reports are not based on any scientific evidence but are speculation and hearsay,” the ministry said.

Five adult cheetahs among the 20 brought into Kuno from Africa and three of the four cubs born in Kuno have died since March. “As per preliminary analyses by the NTCA… all mortalities are due to natural causes,” the ministry said.

The NTCA said it was consulting international cheetah specialists from South Africa and Namibia on a regular basis and independent national experts were reviewing existing monitoring protocols, veterinary facilities and other aspects of the project.

Wildlife veterinarians and other cheetah experts tracking the project said they were baffled by the NTCA statement claiming “natural causes”. Two project officials requested by this newspaper to respond to concerns expressed by international experts did not respond.

“It is difficult to define a natural cause — in my view, we applied a collar on the animal and that has been an important factor in the disease process,” said Adrian Tordiffe, an associate professor at the University of Pretoria in South Africa.

Tordiffe said it was not useful to label deaths as natural or unnatural. “It is better to speak of avoidable versus unavoidable deaths. If you know a potential risk and do nothing to mitigate that risk, then it is an avoidable risk and you failed in your responsibility,” he told The Telegraph.

An international conservation official tracking the project who requested anonymity said the NTCA statement appeared to be “an attempt to whitewash or obfuscate instead of maintaining high levels of transparency and openness on a conservation project the world is watching”.

“The project is an experiment with inherent uncertainties and unpredictable outcomes. There should be no pressure to hide anything that takes place,” the official told this newspaper. “Conservationists learn from each event, honing a model for cheetah introductions.”