A person in the city of Guangde, in eastern China, was taken ill on Sunday, officials said.
It comes following the news two brothers in China’s northern Inner Mongolia region were detected to have bubonic plague, known as the “Black Death” in the Middle Ages.
China’s state-run People’s Daily Online reported the city of Bayannur has a “level 3 warning of plague prevention and control”.
And now tests are being carried out by government officials to find out if anyone else in surrounding neighbourhoods in Guangde has also contracted dengue fever.
Dengue fever is spread by infected mosquitos and can cause death in extreme cases.
In a statement, state broadcaster CCTV said the patient has been in hospital since being diagnosed with dengue fever.
They had previously travelled to India, Myanmar and Pakistan.
Singapore is currently battling a dengue fever outbreak, with 15,273 cases identified this year.
The outbreak has been linked to 16 deaths.
Those who come down with the illness, which is transmitted by the Aedes mosquito, usually experience muscle pains and fever as well as vomiting and headaches.
The World Health Organization (WHO) has said it is “carefully” monitoring the case of bubonic plague in China.
“We are monitoring the outbreaks in China, we are watching that closely and in partnership with the Chinese authorities and Mongolian authorities,” WHO spokeswoman Margaret Harris told a UN press briefing in Geneva.
“At the moment we are not considering it high-risk but we are watching it, monitoring it carefully,” she added.
The bubonic plague, known as the “Black Death” in the Middle Ages, is a highly infectious and often fatal disease that is spread mostly by rodents.
Cases are not uncommon in China although they are becoming increasingly rare.
WHO said access to proper medical care lowers the fatality rate of severe dengue to below 1%.