The 'Hygiene Hypothesis' Has Been Proposed as an Explanation for the Rapid

Multiple Choice

The 'hygiene hypothesis' has been proposed as an explanation for the rapid increase in allergies and asthma incidence in Western countries over the last half century. One line of evidence supporting this hypothesis is:

A) Individuals living in Western countries have fewer CD4 T_reg cells in their mucosal tissues.
B) Individuals of African descent have much higher incidence of atopic disease when living in Western countries.
C) Individuals that are infected with RSV as infants are protected from developing allergies and asthma later in life.
D) Individuals that are infected with Hepatitis A virus are more likely to develop allergies and asthma.
E) Persistent exposure with helminthic parasites predisposes individuals to developing atopic diseases due to increased Type II immune responses.