In "A Short History of Nearly Everything," Bill Bryson discusses the unique relationship between mosquitoes and HIV, noting that current scientific understanding suggests that mosquitoes do not transmit HIV. This is because when mosquitoes ingest the virus, their metabolism breaks it down, preventing it from being passed on to humans. This provides a sense of relief, as HIV, the cause of AIDS, remains an issue that is not exacerbated by these common insects.

However, Bryson warns that this situation could change if HIV mutates in a way that allows it to survive within mosquitoes. Such an evolution could pose a serious threat to public health, leading to increased transmission rates and complicating efforts to manage the virus. The quote emphasizes the precarious balance we live with regarding diseases and the potential for unforeseen challenges in our fight against them.