The resurgence of the coronavirus in many countries is "driven in part by younger people letting down their guard during the Northern Hemisphere summer," World Health Organization Director-General Tedros Adhanom Ghebreyesus said Thursday.
Young adults, many without masks, are ignoring social distancing recommendations to pack bars, nightclubs, and beaches that have been reopened since authorities lifted coronavirus restrictions.
"The majority of young people infected tend to have more mild disease. But that's not always consistent," said Maria Van Kerkhove, a WHO epidemiologist who called nightclubs "amplifiers of transmission."
Young people who show mild or no symptoms can spread the virus to more-vulnerable older people.
In Brazil, President Jair Bolsonaro, who tested positive for the coronavirus on July 7 and then negative last Saturday, said that after 20 days indoors he had mold on his lungs. He is being treated with antibiotics. He had repeatedly referred to COVID-19 as "a little flu."
Brazil, as of Thursday evening, had 2.6 million confirmed cases and 91,263 deaths, according to the Johns Hopkins Coronavirus Resource Center.
Among the confirmed cases is Brazil's first lady, Michelle Bolsonaro, who tested positive on Thursday, according to a statement from the presidential palace. Science and Technology Minister Marcos Pontes also said he had tested positive for the virus, making him the fifth cabinet minister diagnosed publicly.
The leader of the northeastern Spanish region of Catalonia is warning young adults to stop partying or authorities may have to reimpose harsh restrictions.
Britain is reporting its highest number of new COVID cases since late June, with officials warning that more quarantines may be necessary.
British health officials registered 846 new cases Thursday and Minister for Health and Social Care Matt Hancock said a second wave of the virus is rolling across Europe and that Britain must defend against it.
"It is absolutely vital as a country that we continue to keep our focus and our discipline, and that we don't delude ourselves that somehow we are out of the woods or that that is all over, because it isn't all over," Prime Minister Boris Johnson said Thursday.
British authorities added Luxembourg to the country's quarantine list, meaning travelers from there must isolate for 14 days after entering Britain. Spain, which had been dropped from the list, has been reinstated and other countries may be added.
Botswana's capital, Gaborone, reimposed a two-week lockdown on Thursday after a surge in new confirmed COVID-19 cases. The increase came as the WHO warned of easing coronavirus restrictions throughout Africa. The WHO says the number of infections on the continent has doubled in the past month.
"We are concerned that ... we will see an increase in cases as we have seen in [other] countries" where restrictions have been eased too soon," WHO Regional Director for Africa Matshidiso Moeti said.
She said more than 20 African countries have recorded more new cases than in the previous weeks, with South Africa accounting for the most but increases also reported in Kenya, Madagascar, Nigeria, Zambia and Zimbabwe.
Moeti said Uganda, Seychelles and Mauritius are doing well in controlling the virus.
Cuba reported nine new cases Thursday, and 37 new cases earlier this week. Just 10 days ago, Cuba reported no new cases for the first time since the outbreak began in March. However, it has reported no deaths for more than two weeks.
Cuba has so far been relatively successful in fighting COVID-19, but the island's top epidemiologist, Francisco Duran, said Thursday that Cubans are getting careless.
"People are holding different types of gatherings without taking into account distancing and often without even using a face mask," he said. "Each small peak underscores a lack of discipline ... prompting stricter measures."
In Florida, Key West police arrested a couple who tested positive for COVID-19 for being in public in defiance of a quarantine order.
Neighbors who videotaped the couple strolling and shopping gave the tapes to police.
The couple's arrest is among the first in the state for violating a quarantine.
Florida, with 461,000 coronavirus cases and 6,600 deaths, is second only to California, which has 492,000 confirmed cases and 8,965 deaths, among U.S. states.
National Geographic magazine is reporting that the first dog in the United States sickened by COVID-19 has died.
Buddy, a 7-year-old German shepherd in New York became ill in April while his owner was recovering from the coronavirus.
Buddy had the same symptoms as human patients, including difficulty breathing. He was euthanized earlier this month after he started vomiting and urinating blood and could no longer walk.
Buddy's doctors said he was also suffering from cancer. Doctors say humans with pre-existing conditions are more susceptible to COVID-19.
The WHO says pet-to-people transmission of the coronavirus is unlikely.
National Geographic says 12 dogs and 10 cats have tested positive for coronavirus in the U.S.