CHICAGO: Philanthropist Bill Gates on Friday urged wealthy nations to help low and middle-income countries strengthen their health systems in hopes of slowing the spread of the coronavirus, which Gates said has started to behave like a "once-in-a-century" pathogen."By helping countries in Africa and South Asia get ready now, we can save lives and also slow the global circulation of this virus," Gates, the former chairman and chief executive of Microsoft Corp, wrote in an editorial in the New England Journal of Medicine.The novel coronavirus that first emerged in China and has now spread to 46 countries is much harder to stop than similar viruses that caused the Middle East Respiratory Syndrome (MERS) or Severe Acute Respiratory Syndrome (SARS), Gates wrote. The Bill and Melinda Gates Foundation has already pledged $100 million to fight the outbreak.Gates' plea was echoed on Friday by the World Health Organization (WHO), which said the risk was very high that the virus would spread and have a global impact.The WHO implored governments to swing into action to contain the virus before it becomes widespread. Such actions could slow the virus, giving nations more time to prepare, officials said."Health systems around the world are just not ready," Dr Mike Ryan, head of the WHO emergencies program, told a news briefing.Gates said the world needs to invest in disease surveillance and better technology to accelerate the development of safe and effective vaccines and drugs.Besides technical solutions, Gates called for better diplomatic efforts to drive international collaboration and data sharing, and increased government spending on drugs and vaccines that would give private companies incentives to take up such efforts.