Meanwhile, hospitals lack water and vaccines are scarceTHE BLACK market in Venezuela has taken a dark turn in recent weeks. In online chat groups, where weary Caracas residents trade everything from detergent to US dollars, covid-19 is the dominant theme. Emotional pleas for medicine are commonplace. The price of oxygen tanks and masks is soaring. So too is rental space for the large refrigerators needed to preserve bodies in the tropical heat, as waiting lists for burials and cremations grow. Switch on state television and it is another world. Every Sunday Nicolás Maduro, the dictator, addresses the nation. Wards of...