A rumor that Uzbek President Islam Karimov has suffered a debilitating heart attack is spreading as quickly as a pandemic in a thriller. As more media outlets reprint the rumor, it may be increasingly perceived as the truth, but in fact the sourcing remains as thin as it was when this started last weekend.  

The allegations all go back to the same person, an exiled opposition figure thousands of miles away in Norway – Muhammad Solih, head of the People’s Movement of Uzbekistan (PMU). On March 22, Solih’s website cited an unnamed source in Tashkent as saying Karimov, 75, had suffered a heart attack after attending festivities marking the Navruz spring holiday. On March 24, Solih reiterated the rumor by citing a second source, a journalist “working for one of the state media outlets, performing his activities directly under the oversight of the National Security Committee and the press service of the president of Uzbekistan.” 
There are a few denials, too. Today a senator told Radio Free Europe that Karimov is in perfect health and maybe he would attend a senate session on March 28. Moreover, yesterday the president’s eldest daughter, Gulnara Karimova, tweeted that her father is just fine. If anyone doesn’t believe her, he was seen a week ago at the Navruz festivities. (It’s now been more than a week.) And in a non-denial of sorts, today word emerged that Karimov would travel to Moscow on April 15. But that’s a lot of heartbeats from now. 
On March 25, the Russian news agency Rosbalt picked up Solih's story, basically copying his original post word-for-word. 
That’s when the rumor really took off. Who went next isn’t clear, but it’s now all over dozens of Russian-language sites covering the former Soviet Union – mostly verbatim from Solih. Today Vechernii Bishkek cites Zakon.kz in its lede, noting that another source has come forward. But the Zakon.kz report cites Solih and Rosbalt (so Solih) and Newsru.com, which cites Solih. So Vechernii Bishkek's second source is via Solih.
Even the Committee to Protect Journalists (CPJ), the New York-based watchdog, cites Russian and Kazakh media “citing their own sources in Tashkent.” But a close look shows the CPJ is reading stories based almost entirely on Solih’s allegations. 
CPJ cites Kazakhstan’s Respublika, which cites, you guessed it, Solih. And Rosbalt. So Solih. Respublika adds that Karimov’s younger daughter (the one who sued a French newspaper for calling her a “dictator’s daughter”), Lola Karimova-Tillyaeva, has rushed home in recent days. (As Uzbekistan’s permanent representative to UNESCO, Karimova-Tillyaeva presumably visits Uzbekistan from time to time.) CPJ also cites Lenta.ru, which cites Solih and Rosbalt. 
So, in other words, we have Solih – a Karimov rival who fled Uzbekistan almost 20 years ago – as the only source. Unfortunately, that's how we get a lot of our news out of tightly controlled Uzbekistan these days: from single sources who are often abroad.
Certainly, Karimov’s incapacitation or death would be big news, possibly ushering in a struggle for power. Until we see the man in person, there’s no sure-fire way to confirm that something isn’t up. But the sourcing on the heart-attack rumors is desperately thin. It’s almost like someone is wishing Karimov would have a heart attack.