Table VI.

Associations between enrollment groups and identification of lesions at enrollment using ultrasonography

Comparison groups (LAE present)	Relative riska	95% CI	P-value
Case versus controls
Arrival fever cases versus arrival controls	1.45	0.27 to 7.67	0.663
Post-arrival fever cases versus post-arrival controls	11.96	2.34 to 61.07	0.003
Post-arrival no fever cases versus post-arrival controls	3.24	0.33 to 31.42	0.311
Post-arrival fever cases versus post-arrival no fever cases	3.69	1.37 to 9.97	0.010
Case versus case
Arrival fever cases versus post-arrival cases (fever and no fever cases combined)	0.52	0.13 to 2.04	0.352

^aRelative risk is the ratio of the rate of disease in the first group divided by the rate of disease in the second group in that comparison.

LAE — lesion at enrollment; 95% CI — 95% confidence interval calculated for each relative risk using Poisson regression in a log linear model for comparison group effects and correcting for intra-pen clustering of disease with generalized estimating equations.