Sturgess' partner Charlie Rowley, 45, also fell victim to the poisoning incident and remains hospitalized in critical condition.
The British defense lab determined earlier that Novichok, a type of nerve agent developed by the Soviet Union during the Cold War, was used on Sergei Skripal, a former Russian intelligence officer once convicted in his homeland of spying for Britain.
Moscow hit back by expelling Western diplomats.
Sajid Javid said both towns remain open for business and urged people to visit what he called one of the most lovely parts of the country.
Assistant Commissioner Neil Basu, the head United Kingdom counter-terrorism policing which is leading the investigation, said he was "unable to say" if the incident in Amesbury is linked to the poisoning of the Skripals on 3 March - but it is their "main line of inquiry". He had also fallen ill and was taken to the hospital.
Police are hunting for a contaminated container which they believe was handled by the pair, who were known drug users.
Defence Secretary Gavin Williamson blamed Russian Federation for committing "an attack on British soil" over the latest poisonings, some four months after Sergei and Yulia Skripal were targeted. Britain has notified the global chemical weapons watchdog, the Organisation for the Prohibition of Chemical Weapons.
Both were determined to have been exposed to the nerve agent after touching a contaminated item with their hands, police said. Yulia said that the poisoning had turned her life "upside down" and that she and her father were "lucky to have survived this assassination attempt". He also said there were no plans at this stage for further sanctions against Russian Federation. Sturgess was taken to hospital around 10.15am and Rowley several hours later, around 3.30pm.
An exterior view shows Charlie's Store open as usual, in which CCTV from inside appeared to show Dawn Sturgess the day before she became seriously ill, in Salisbury, England, July 6, 2018.
Basu said that detectives would need forensic evidence before definitively concluding that the Novichok used in the first attack had made the British couple ill.
A police officer was tested for possible exposure to the deadly nerve agent over the weekend but was given the all-clear.
Met Police assistant commissioner Mr Basu said: 'Detectives from the UK's counter-terrorism policing network are unable to say at this moment whether or not the nerve agent found in this incident is linked to the attack on Sergei and Yulia Skripal, however this remains our main line of inquiry. Police said there is no evidence that either Sturgess or Rowley visited any of the sites where the Skripals may have been poisoned.
"We are not in a position to say whether the nerve agent was from the same batch that the Skripals were exposed to", Basu said.