Chapter 22

Vaginal yeast infections are caused by the fungus Candida albicans, which is one of a community of microorganisms that are always present in the vagina in low concentrations. One of the factors that can bring about a yeast infection is the initiation of the use of certain antibiotics. Why would the use of antibiotics foster an unhealthy multiplication of \(C\). albicans in the vagina?

The Entomophthora muscae fungal parasite that invades flies has no consciousness, yet it manages to undertake actions that affect the behavior of the flies it attacks. (It sends hyphae into the flies' brains, and as a result, the flies crawl upward.) Almost all parasitism is disturbing to human sensibilities, but this brand is particularly unsettling. Why should this be so?