The US military population has been treated with wide range of vaccinations/ immunisations (often 20 plus) far beyond the scope of most of the general public population of developed nations. so an illness among a US military personnel population may not be representative of how the same illness moves/ presents/ effects a general public population.
Maybe everyone might stay healthier or not get so sick if they were vaccinated against anthrax, diphtheria etc
https://academic.oup.com/epirev/article/28/1/3/567796