Systemic lupus erythematosus
The rate of SLE varies between countries, ethnicity, and sex, and changes over time. In the United States, one estimate of the rate of SLE is 53 per 100,000; other estimates range from 322,000 to over 1 million. In Northern Europe the rate is about 40 per 100,000 people. SLE occurs more frequently and with greater severity among those of non-European descent. That rate has been found to be as high as 159 per 100,000 among those of Afro-Caribbean descent. Childhood-onset systemic lupus erythematosus generally presents between the ages of 3 and 15 and is four times more common in girls.
Prevalence of rabies
In the midwestern United States, skunks are the primary carriers of rabies, composing 134 of the 237 documented non-human cases in 1996. The most widely distributed reservoir of rabies in the United States, however, and the source of most human cases in the U.S., are bats. Nineteen of the twenty-two human rabies cases documented in the United States between 1980 and 1997 have been identified genetically as bat rabies. In many cases, victims are not even aware of having been bitten by a bat, assuming that a small puncture wound found after the fact was the bite of an insect or spider; in some cases, no wound at all can be found, leading to the hypothesis that in some cases the virus can be contracted via inhaling airborne aerosols from the vicinity of bats. For instance, the Centers for Disease Control and Prevention (CDC) warned on May 9, 1997, that a woman who died in October 1996 in Cumberland County, Kentucky and a man who died in December 1996 in Missoula County, Montana were both infected with a rabies strain found in silver-haired bats; although bats were found living in the chimney of the woman's home and near the man's workplace, neither victim could remember having had any contact with them. Similar reports among spelunkers led to experimental demonstration in animals. This inability to recognize a potential infection, in contrast to a bite from a dog or raccoon, leads to a lack of proper prophylactic treatment, and is the cause of the high mortality rate for bat bites.