Prevalence and Incidence of West Nile fever
West Nile fever: Rare Disease
West Nile fever is listed as a "rare disease" by the Office of
Rare Diseases (ORD) of the National Institutes of Health
(NIH). This means that West Nile fever, or a subtype of West Nile fever,
affects less than 200,000 people in the US population.
Prevelance of West Nile fever discussion:
In 1999, 62 cases of severe disease, including 7 deaths, occurred
in the New York area. In 2000, 21 cases were reported, including 2 deaths
in the New York City area. In 2001, there were 66 human cases of
severe disease and 9 deaths. No reliable estimates are available for the
number of cases of West Nile encephalitis that occur worldwide. (Source: excerpt from West Nile Virus Questions and Answers: DVBID)
About prevalence and incidence statistics:
The term 'prevalence' of West Nile fever usually refers to the estimated population
of people who are managing West Nile fever at any given time.
The term 'incidence' of West Nile fever refers to the annual diagnosis rate,
or the number of new cases of West Nile fever diagnosed each year.
Hence, these two statistics types can differ:
a short-lived disease like flu can have high annual incidence but low prevalence,
but a life-long disease like diabetes has a low annual incidence but high prevalence.
For more information see about prevalence and incidence statistics.