Zimbabwe's four major hospitals are being overwhelmed by patients as a week-old strike by the country's junior doctors strike intensifies, the head of their union said Thursday. Hundreds of junior doctors in the two central hospitals in Harare and two in the western city of Bulawayo downed tools last week in a row over pay. The doctors are demanding an increase in pay from the 370 dollars they have been receiving from the power-sharing government formed in February by President Robert Mugabe and Prime Minister Morgan Tsvangirai. "It's a very serious situation," said Dr Brighton Chizhande, head of the Hospital Doctors Association which comprises doctors doing their post-graduate training. "The hospitals are doing only emergency cases. Some outpatients departments are closed. Theatre cases are markedly reduced." He said senior doctors not on strike were "overwhelmed" as they were forced to take over the minor but essential procedures usually done by junior doctors. Junior doctors in smaller district hospitals in the countryside had not yet joined the strike, but these were receiving larger allowances from the Global Fund to Fight AIDS, Tuberculosis and Malaria, he said. Doctors at the central hospitals were being paid by the government and a coalition of Western donors. Zimbabwe's state health system shut down almost entirely last year as the country's economic crisis, marked by hyperinflation and a worthless currency, saw hospitals run out of drugs, food, medical equipment and bedding and medical staff were on strike for over a year. The worst cholera epidemic in Africa in recent year, which caused around 4,000 deaths, was ended only by the intervention of Western aid agencies. Economic reforms introduced by Tsvangirai's Finance Minister Tendai Biti produced immediate results, with doctors agreeing to return to work for low pay on condition of later pay rises. "There is a lack of seriousness on the part of government," Chizhande said, citing the possibility of a swine flu outbreak or a further cholera outbreak. "This is a matter of life and death for the patients.