The region in the body where the polio virus multiplies is

Which of the following insects transmits relapsing fever

$A$ : It is considered advantageous to give the polio vaccine orally.
$R$ : It prevents reinfection by causing intestinal immunity

During an allergic reaction, the binding of antigens to IgE antibodies initiates a response, in which chemicals cause the dilation of blood vessels and a host of other physiological changes. Such chemicals are

Filaria, malaria, dengue fever, sleeping sickness, yellow fever are transmitted by

Excessive dosage of cocaine causes