Figure 1.

Diet affects foot swelling but not viremia. (A) Mice (C57BL/6J) were fed on either a high fiber diet, a standard diet or a no fiber diet for 3 weeks and were then infected with CHIKV and maintained on the same diet for the duration of the experiment. Foot swelling was measured over time and was higher in the high fiber group compared with the no fiber group; ***p < 0.001, **p = 0.008 (Day 7 approached significance p = 0.051), t-tests; n = 28–30 feet from 14 to 15 mice, with data from two independent experiments shown. (B) Viremia for the mice described in (A). (C) Mice were fed on a standard diet and water was supplemented with 200 mM of the indicated SCFA for the duration of the experiment. Foot swelling was measured over time. Mice drinking butyrate had significantly increased foot swelling than control mice (standard water); ***p < 0.001, **p ≤ 0.003, *p < 0.04, t-tests; n = 12 feet from six mice. (D) Viremia for the mice described in (C). (E) Mice were fed on a no fiber diet and the drinking water was supplemented with butyrate, or were fed a no fiber diet and supplied water for the duration of the experiment. After 3 weeks mice were infected with CHIKV and foot swelling measured. Butyrate significantly increased foot swelling; ***p < 0.001, **p = 0.01, *p < 0.04, t-tests; n = 22–24 feet from 11 to 12 mice, with data from two independent experiments shown. (F) Viremia for the mice treated as described in (E); n = 6 mice, one experiment. (G) Mice were fed on a high fiber diet and the drinking water was supplemented with butyrate, or mice were fed on a no fiber diet and supplied unsupplemented water. After 3 weeks mice were infected with CHIKV and foot swelling measured. Butyrate/high fiber showed significantly increased foot swelling; ***p < 0.001, *p < 0.04, t-tests; n = 24 feet from 12 mice, with data from two independent experiments shown. (H) Viremia for mice treated as described in (G); n = 6 mice, one experiment.