Day of onset of mortality among units in groups at Site C. A Group 2, 24 baskets on a hanging long line. There are unaffected baskets between those affected at days 11, 19 and 26, which is evidence against direct transmission between units. Basket 14 affected at day 19 is adjacent to basket 15 affected at day 11, which is consistent with direct transmission because the interval between days 11 and 19 is within one hypothetical incubation period. B Group 12, 12 baskets on a hanging long line. There are no examples of direct transmission from basket 10, which was the first one affected, or subsequently from baskets 7, 8 or 12. C Group 34, 8 segments of a tray. There are no examples of direct transmission from segment 5, the first one affected. D Group 36, 8 segments of a tray. Direct transmission may have occurred between segments affected at day 33 and day 40.