Cell mediated immunity is mainly a function of
$B-$cells
$T-$cells
Macrophages
Interferons
A chemical substance produced by a microorganism for inhibiting the growth of another is
Louse is ectoparasite of
Which group of three of the following five statements $(I-V)$ contains is correct regarding beriberi?
$I.$ A crippling disease prevalent among the native population of sub-Sahara Africa.
$II.$ A deficiency disease caused by lack of thiamine (vitamin- $B_{1}$ ).
$III.$ A nutritional disorder in infants and young children when the diet is persistantly deficient in essential protein.
$IV.$ Occurs in those countries where the staple diet is polished rice.
$V.$ The symptoms are pain from neuritis, paralysis, muscle wasting, progressive oedema, mental deterioration and finally heart failure.
Main barrier which prevents the entry of disease's causing organism in our body is
Widal test is used for the diagnosis of