A surge in internet searches about gut ailments is helping researchers predict the next Covid-19 hotspots, a study has revealed.
Massachusetts General Hospital found areas where there was a spike in Google queries relating to diarrhoea and loss of appetite frequently reported a sharp rise in cases of coronavirus three to four weeks later.
Other markers included a loss of taste, nausea and abdominal pain.
A link between Covid-19 and gut ailments was first identified in China earlier this year, with about a third of sufferers reporting gastrointestinal rather than respiratory sickness. Other patients complained of suffering from both.
The link between gut problems and the virus prompted Massachusetts researchers to examine data from the Google Trends online tool.
Researchers examined material from 15 states and tracked the search results against the incidence of the disease four weeks later. They found that the data provided a potential Covid-19 early warning system.
The correlation was particularly marked in New York, New Jersey, California, Massachusetts and Illinois which were among the worst-hit states at the start of the pandemic.
“Our data underscore the importance of GI symptoms as a potential harbinger of Covid-19 infection and suggests that Google Trends may be a valuable tool for prediction of pandemics with GI manifestations,” Kyle Staller, one of the study’s authors, told Bloomberg.
Other techniques for tracking the disease include testing wastewater - a method which was used in the past for early detection of diseases such as polio.
It is credited with heading off a major coronavirus outbreak at the University of Arizona last month. Similar methods have been used in Israel to track Covid-19 outbreaks across geographic regions.
According to the Centres for Disease Control and Prevention in the US, sewage testing is intended to complement, rather than replace, conventional coronavirus testing.