Cause of Navalny illness may be unknown for days

Bloomberg

Alexei Navalny, the Russian anti-corruption campaigner who has been in a coma since last week, is being examined at a German hospital and it may be days before officials can confirm or reject accusations that he was poisoned.
Navalny was in “very critical” but stable condition according to an ally who helped organise his evacuation from Russia to Berlin’s Charite hospital. The
results of the tests and a prognosis may not be available for several days, Leonid Volkov, his chief of staff, said.
His sudden and severe illness has raised suspicions after a string of Kremlin critics have become victims of poisoning. Dissident security service officer Alexander Litvinenko died in London after consuming tea laced with polonium in 2006 and ex-spy Sergei Skripal survived an assassination attempt with a weapons-grade nerve agent, Novichok, in England’s Salisbury in 2018.
UK officials linked both attacks to the Russian state.
“Much speaks for poisoning frankly,” Thomas Daldrup, a forensic toxicologist from the University of Duesseldorf, said. “If the substance was intended to do its damage and then decay quickly in the body, then it may be difficult to establish a forensic picture of the attack.