South Africa has now registered more than 500,000 cases of coronavirus, the health ministry announced Saturday, making it by far the hardest-hit country in Africa. The country has become the epicentre of the deadly pandemic on the continent, accounting for more than half of Africa's diagnosed infections. "Today South Africa has exceeded the half-a-million mark with a cumulative total of 503,290 confirmed COVID-19 cases recorded," Heath Minister Zweli Mkhize said in his daily update. More than a third of positive cases are in Gauteng province -- South Africa's financial hub. So far the number of fatalities stands at 8,153, although local researchers have recorded a jump of nearly 60 percent in the overall number of natural deaths in recent weeks, suggesting a far higher toll of coronavirus-related fatalities than officially recorded. An analysis by the respected South African Medical Research Council (SAMRC) suggested an excess of 22,000 natural mortalities between May 6 and July 21 compared to same period in 2019 and 2018. President Cyril Ramaphosa said Saturday South Africa's case fatality rate stood at 1.6 percent -- "significantly lower than the global average". "While South Africa has the fifth highest number of total COVID-19 cases globally, we have only the 36th highest number of deaths as a proportion of the population," said Ramaphosa. - Corruption investigations - South Africa's case load has been rising rapidly in recent weeks. Health authorities have been expecting a surge in cases after the gradual loosening of a strict lockdown that was imposed on March 27, during the early stage of the pandemic. But the recovery rate has so far been a high 68 percent. South Africa has one of the best health care systems on the continent, but it has been rocked by alleged corruption in the supply of personal protective gear for health workers in public hospitals. Ramaphosa's spokeswoman Khusela Diko last week took leave pending a probe into her husband's alleged links to unlawful contracts for personal protective equipment. Diko and her husband have maintained their innocence, saying the contract was never finalised. The health minister for Gauteng province Bandile Masuke was sent on forced leave this week pending a probe into suspected graft in the purchase of protective equipment and other medical supplies. "It is unconscionable that there are people who may be using this health crisis to unlawfully enrich themselves," Ramaphosa said in his statement Saturday. South Africa has embarked on an aggressive testing and tracing exercise, conducting more than three million tests since the first case of the virus was recorded there in early March.