8. What is the geographic distribution of chronic infection?
If you’re in a high area, your lifetime risk
of getting infected is higher than sixty percent. And for most of those areas, it’s up to
eighty or ninety percent. If you’re in an intermediate area, then your
lifetime risk of infection is somewhere between twenty and sixty
percent. And if you’re in a low risk area, your risk
is less than twenty percent. So in the high risk area people get infected
as young children. In the intermediate area, you have some
people getting infected as young children and some getting infected at
older ages. And in the low risk area, almost all of the
infections are adults and usually because of one risk behavior or
another. So, these are the areas of the world where
you find the high, intermediate, and low risks and you can see that
the red areas cover large parts of East Asia, Southeast Asia,
Sub-Saharan Africa. The band in South America are South American
Indians. It’s not the European populations that are
infected and so it’s actually the Amazon Basin where the Indian
populations have twenty percent or higher prevalence of hepatitis
B. And the same is true for Northern Canada,
Alaska, and Greenland; those are by and large either Indian or Inuit
populations. And the intermediate populations in yellow,
a lot of Eastern Europe and the Soviet Union still have pretty high
prevalence of chronic carriers.
7. What is the global pattern of chronic infection?
9. What is the incidence of liver cancer in males?