In Nigeria fake news can be so outlandish, yet widely believed, that the president recently felt compelled to declare that he had not died and been replaced by a Sudanese body double.
"It's (the) real me, I assure you," President Muhammadu Buhari said late last year, to dispel the story that was viewed more than 500 000 times on Facebook, Twitter and YouTube.
Nigeria's fake news can also be lethal.
The stakes are high in Nigeria ahead of Saturday's presidential vote marked by widespread discontent over unemployment, poverty and insecurity in some parts of the country. Officials warn that fake or outdated pictures depicting communal violence trigger retaliatory killings.
Many were killed in reprisal killings sparked by horrific, but false, photos purporting to depict deaths in the conflict between herdsmen and farmers in central Nigeria last year, said Tolu Ogunlesi, a media assistant to Nigeria's president.
"Fake news kills people. We have seen a lot of things like that," he said. "Some of the deadly clashes in Nigeria were sparked off by fake news." He suggested that "the naming and shaming of members that peddle fake news" could stem the problem.
Africa's most populous country is so awash in falsehoods posted, Facebook and YouTube that 16 media outlets have been collaborating on a fact-checking initiative, CrossCheck Nigeria, to research suspect election claims circulating online.
Some of the stories CrossCheck Nigeria recently discredited include allegations the first lady wants Nigerians to vote against her husband, as well as a suggestion that US President Donald Trump endorsed opposition candidate Atiku Abubakar. Such allegations almost always appear on social media and sometimes are published by news websites.
The project is similar to Africa Check, which calls itself the continent's first fact-checking organisation and has operated since 2012.
In the United States the term 'fake news' became frequently used after the 2016 election, which was allegedly marked by a Russian misinformation campaign. But in Africa fake news has long been a contentious matter, fuelled in part by illiteracy and government secrecy even as the continent's 1.2 billion people rapidly acquire mobile handsets and gain internet access. The issue is now urgent: More than 24% of people on the continent were online last year, the strongest growth in the world, according to the UN agency International Telecommunication Union.
Some African governments want to make publishing fake news a crime, a step too far for journalists in countries where the press already is censored and reporters can be jailed for critical stories.
Kenyan President Uhuru Kenyatta last year signed a cybercrimes bill that calls for fines and prison sentences for people convicted of spreading fake news. The law followed a disputed 2017 presidential election marred by online misinformation campaigns that raised political tensions in a country known for deadly post-vote violence along ethnic lines.
In Uganda, where there has been a surge in false news seen as portraying the government negatively, authorities warn that perpetrators face charges under a 2011 law prescribing criminal penalties for the misuse of a computer.
But activists warn that countering misinformation with legislation could be used to censor the press. The Committee to Protect Journalists opposed Kenya's law over concerns it would stifle press freedom. In Uganda there also has been resistance from the courts.
Consequence of spreading fake news
A Ugandan opposition activist was jailed last year on charges that he falsely accused the government of trying to kill pop star and politician Bobi Wine. A magistrate ordered the activist, Moses Bigirwa, freed in January, ruling that publishing fake news was not a crime.
Some governments in Africa have been accused of spreading misinformation themselves or maligning reports that were true. Authorities in Nigeria frequently challenge the veracity of reports of alleged abuses by military officers during campaigns against militants. They also have fiercely disagreed when human rights watchdogs, citing witnesses on the ground, report higher death tolls than the government's official ones.
Reports by Amnesty International's Nigeria office on the conduct of Nigerian troops fighting Islamic extremist group Boko Haram have created conflicts with the military, which has accused the local branch of the human rights group of publishing false accounts.
"Fake news has become like a cliche and ticket for demonising the journalist, the media and the NGOs," Amnesty International Nigeria spokesperson Isa Sanusi said, noting that false news spreads quickly in Nigeria because public officials often are not open with government information.
"The only thing that is fuelling it is the fact that information is not available," he said. "The solution to stopping fake news in Nigeria is transparency, particularly from the side of the authorities."
False reports spread on social media so fast and frequently that some people who are the subjects of it simply have to laugh.
Nigerian writer and Nobel laureate Wole Soyinka said during a BBC-hosted conference on the spread of false news in Nigeria that he enjoyed reading the regular obituaries of his death.
Underscoring the severity of the problem, however, Soyinka warned that "if we are not careful, World War III will be started by fake news, and that fake news will probably be generated by a Nigerian".