Cases of coronavirus could be missed in South East Asia because the region is undergoing a simultaneous outbreak of dengue fever, a team of experts has warned.

South East Asian nations have reported generally low numbers of confirmed cases despite the region’s close ties to China, with experts attributing this partly to its hot weather conditions.

But writing in The Lancet, a team of Singapore-based doctors said the dengue outbreaks in Singapore, Malaysia and the Philippines could complicate efforts to track and contain Covid-19.

The paper cites two patients in Singapore who presented with symptoms such as fever and coughing, and had antibody tests which showed up as positive for dengue. They were later found to have contracted coronavirus, however.

“Dengue and coronavirus disease 2019 (Covid-19) are difficult to distinguish because they have shared clinical and laboratory features,” the authors wrote.

It comes as Indonesia reported its first coronavirus death on Wednesday, a 53-year-old British woman who was visiting Bali and had a number of pre-existing medical conditions.

She was already in a critical condition when she was admitted to hospital, said official Achmad Yurianto, though he did not say which hospital or city she was in.

Indonesian officials also did not name the woman’s country of origin, but the UK Foreign Office confirmed the death of a British national in Bali and said it was supporting the family.

“[The patient] had underlying conditions of high blood pressure, hyperthyroidism and long years of obstructive lung disease,” he said.

She died at around 2am on Wednesday. “Coronavirus had reduced her immune system, and in turn worsened her pre-existing medical conditions,” he told a news conference. “The embassy has been informed.”

Indonesia’s number of coronavirus cases has more than quadrupled in just a few days, up to 27 on Tuesday from six on Sunday.

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An updated tally was not immediately available for Wednesday, but Mr Achmad said the government was “continuing to do close contact tracing on all the 27 confirmed cases”. He said that 736 people had been tested in total as of Wednesday morning.

With the sharp rise in cases, the world’s fourth most populous nation has stepped up measures to contain the virus.

That includes banning entry to travellers from the 10 worst-hit countries, including Iran, Italy and South Korea.

The healthy ministry said Jakarta had received an additional 10,000 rapid PCR (polymerase chain reaction) tester kits on Tuesday, kits which are less accurate than swab tests but produce quicker results.

At least two of its earliest cases are now believed to have recovered, having received two negative tests, and are being released from hospital, Mr Achmad said. They were now being “educat[ed] before they go home so they can properly conduct self-isolation”, he said.

Singapore has confirmed 160 cases but no deaths in the coronavirus outbreak. Malaysia has had 129 cases, and also no deaths.