WARSAW (Reuters) – The arrival of hundreds of thousands of Ukrainian refugees in Moldova is putting huge pressure on its health care system and it has appealed for help from the European Union and U.N. agencies, the country’s health minister said on Tuesday. More than 331,000 refugees have entered Moldova since Russia invaded Ukraine on Feb. 24 and of them 100,000 are still in the country, Ala Nemerenco told a joint press conference with the World Health Organization (WHO), streamed live from Chisinau. Moldova, a small former Soviet republic sandwiched between Ukraine and EU member Romania, is…