The presence of IgG antibodies, specific for the novel coronavirus (SARS-CoV-2), was detected in serum samples collected in December 2019 in the Brazilian state of Espirito Santo, announced the state health department on Tuesday.

The health department said that 7,370 serum samples had been collected between December 2019 and June 2020 from patients suspected of being infected with dengue and chikungunya.

The results showed IgG antibodies in 210 blood samples, among which 16 samples were collected before the country's first officially-confirmed COVID-19 case on February 26, 2020, suggesting earlier presence of the novel coronavirus in the country.

One of the samples was collected on as early as December 18, 2019.

The health department stated that it takes about 20 days for a patient to reach detectable levels of IgG after the infection, so it could have occurred between late November and early December 2019.

The Brazilian Ministry of Health issued a notice on the same day, instructing the state to conduct in-depth epidemiological investigations and send serum samples to Oswaldo Cruz Foundation, Rio de Janeiro, for RT-PCR test.

"Only with confirmation by the reference laboratory and the deepening of epidemiological studies will the Ministry of Health be able to confirm, or not, whether these cases were really positive for SARS-CoV-2," said the ministry.

This is not the first time that Brazil has found evidence for COVID-19 presence earlier than the country's first known case.

The country in July, 2020, reported traces of the novel coronavirus detected from sewage water samples collected in November, 2019 in Florianopolis, the capital and second largest city of the state of Santa Catarina.

"We detected SARS-CoV-2 in two samples collected independently on [the] 27th [of] November 2019," said a report published by 14 researchers at the Federal University of Santa Catarina. "Our results show that SARS-CoV-2 has been circulating in Brazil since late November 2019, much earlier than the first reported case in the Americas."

(With input from Xinhua News Agency)