With his positive coronavirus test, President Donald Trump joins the ranks of other world leaders including Prime Minister Boris Johnson of Britain and President Jair Bolsonaro of Brazil who have been infected. Also having tested positive are the presidents of Bolivia, Guatemala and Honduras and the prime ministers of Armenia and Russia.

Some leaders have been gravely ill — including Johnson, who was hospitalized for a week with the illness, which has killed at least 1 million people worldwide and infected more than 34 million. Others including Bolsonaro appeared to have had only mild cases. In Nigeria, a top aide to President Muhammadu Buhari died of the coronavirus in April.

Here is a rundown of world leaders who have fallen ill and how they handled it.

Britain: Prime Minister Boris Johnson

Johnson, 56, who in the early part of the pandemic resisted a lockdown and social-distancing measures, contracted the virus in March. He was later hospitalized, spending three nights in an intensive care unit, and deputized the country's foreign secretary to carry out his duties.

After Johnson was released from the hospital in April, he thanked Britain's National Health Service, saying that it had "saved my life, no question."

Returning to office in late April, he adopted a more somber and cautious tone, a stark contrast to his initial insistence that Britain would contain the coronavirus without lockdown measures. He eventually brought in such restrictions for nearly two months and warned about the risks of resuming regular public life too quickly.

His government's approach since then has been mixed. During the summer, Johnson encouraged people to return to working in offices to help restart the economy, and offered patrons a government-subsidized discount to eat at restaurants and pubs.

With a second wave of the virus now bringing thousands of new cases every day, Johnson's government again introduced tighter restrictions in England last month, including limits on the size of social gatherings across the country and local shutdowns in places with larger outbreaks. The government is also encouraging people to work from home if they are able to.

To date, Britain has been the worst-hit country in Europe, with more than 56,000 reported deaths.

Brazil: President Jair Bolsonaro

Like Trump, Bolsonaro, 65, was cavalier about the coronavirus, calling it a "measly cold." Even as his country became one of the hardest hit by the pandemic, he attended political rallies, shook hands with supporters and went around without a face mask.

To date, more than 144,000 Brazilians have died from the virus, although Bolsonaro's case appears to have been mild. He said he had experienced aches and a fever.

After later testing negative, he posted a tweet including a picture in which he appears to be smiling and giving a thumbs up while brandishing a box of hydroxychloroquine pills, the anti-malaria medicine promoted by Trump as a remedy for the virus, despite a growing scientific consensus that the drug is not effective in treating COVID-19.

Honduras: President Juan Orlando Hernández

Hernández, 51, tested positive in June along with his wife and two aides, and was treated for pneumonia. He initially vowed to keep working as he displayed mild symptoms, but his health quickly worsened. For days, he remained in a "delicate" situation, doctors said, as he was hospitalized and needed oxygen.

Bolivia: President Jeanine Añez

Añez, 53, who took office as Bolivia's caretaker leader in January after the ouster of President Evo Morales, tested positive for the coronavirus in July. She remained in self-isolation for 14 days, and several government officials also tested positive, including Bolivia's health minister. Añez returned to work in late July.

Guatemala: President Alejandro Giammattei

Giammattei, 64, said last month that he had tested positive for the coronavirus — on the same day that the Central American country reopened its borders and allowed in international flights after a six-month closure.

Giammattei, a former surgeon who walks with crutches after suffering sclerosis in his youth, said his health condition made him a "high-risk" patient.

"My symptoms are very mild. Up to now, I have body aches. It hurt more yesterday than today, like a bad cold," Giammattei told a local radio station, vowing to keep working from home.

Guatemala's culture minister and four government officials were also infected.

Nigeria: President's chief of staff, foreign minister and governors

Abba Kyari, an influential aide to President Muhammadu Buhari, tested positive for the coronavirus in March and died weeks later at a hospital in Lagos. Kyari was one of the most powerful men in the country, acting as a gatekeeper to the presidency.

The country's foreign minister, Geoffrey Onyeama, contracted the virus in July and self-isolated for three weeks. At least eight state governors have also contracted the virus in the past several months.

Armenia: Prime Minister Nikol Pashinyan

Pashinyan, 45, went into self-isolation in June after he and close family members tested positive for the coronavirus. A week later and after displaying no symptoms, he said he had tested negative.

The Armenian authorities eased a weekslong lockdown in May but acknowledged that they had failed to enforce the measures thoroughly and that there had been widespread quarantine violations.

Russia: Prime Minister Mikhail Mishustin

Mishustin, 54, who became prime minister in January, was hospitalized after testing positive for the coronavirus in April. Russia initially boasted a low mortality rate, but the country's have since spiked. The country's death toll has included hundreds of health care workers.

Gambia: Vice president and several ministers

Several Gambian officials tested positive for the coronavirus in August, including Mambury Njie, the finance minister; Fafa Sanyang, the petroleum and energy minister; and Amie Fabureh, the agriculture minister. Vice President Isatou Touray also contracted the virus, leading President Adama Barrow to self-isolate.

"Stay safe, COVID 19 is real," the State House of Gambia said in a tweet announcing that the ministers had contracted the virus.

European Union: Michel Barnier, chief Brexit negotiator

Barnier, 69, tested positive for the coronavirus in mid-March as many European countries imposed stringent lockdown measures and closed their borders to neighbors, and as the European Union banned nonessential travel from outside the bloc.

Barnier said at the time that he was "doing well and in good spirits," and returned to office in mid-April.

Iran: A vice president, top clerics and Parliament's speaker

As Iran struggled with a severe outbreak in February, several government leaders became infected, including Masoumeh Ebtekar, President Hassan Rouhani's deputy for women's affairs. Ebtekar, the highest-ranking woman in the country's government, later said she had recovered.

The speaker of Parliament, Ali Larijani, tested positive in April, and several high-ranking clerics have died of the virus.

India: Multiple politicians and officials

In India, where coronavirus cases are soaring, several politicians have been among those to contract the virus. Suresh Angadi, a junior railways minister who died last week, became the first high-ranking official in the country to die. He was 65.

Canada and Germany: Leaders who isolated but were not infected

As many countries went into lockdown in March, Prime Minister Justin Trudeau of Canada, 48, was the first leader of a major industrialized country to go into self-isolation after his wife tested positive for the coronavirus.

Trudeau said he looked after his three young children while hosting daily meetings with his cabinet or discussing strategies to contain the spread of the virus with other leaders such as Johnson and President Emmanuel Macron of France. Trudeau, who displayed no symptoms, didn't take a test but stayed in self-isolation for nearly three weeks.

Chancellor Angela Merkel of Germany, 66, also self-isolated in March after her doctor tested positive for the coronavirus. But after receiving several negative test results, she returned to office in early April.