The Trump administration has shut down at least one government-run study that uses fetal tissue implanted into mice even before federal health officials reach a decision on whether to continue such research, which is opposed by anti-abortion groups. A senior scientist at a National Institutes of Health laboratory in Montana told colleagues that the Health and Human Services Department “has directed me to discontinue procuring fetal tissue” from a firm that is the only available source, according to an email he sent to a collaborator in late September. “This effectively stops all of our research to discover a cure for HIV,” the researcher wrote. The research disruptions might extend to a handful of other labs using fetal tissue, all of which are part of the NIH, rather than outside research institutions operating on NIH grants, according to an individual familiar with the situation. The shutdown of the HIV research at the federal lab in Montana, first reported in the journal Science, was never disclosed publicly by government officials, who have forbidden affected researchers from discussing what happened.