Nematodes are differentiated from other worms by
|B||Flat or fleshy leaf like worms|
|E||GIT is completely formed|
Nematodes are helminthes which have nonsegmented, cylindrical body with tapering ends. They have a complete alimentary canal are bisexual.
There is a marked periodicity in the circulation of microfilariae in the blood. The periodicities exhibited by different species of microfilariae are as follows:
a. The microfilariae are present in high numbers in the peripheral blood during a 4 hour period at mid night and scanty or absent during daytime.
b. This type of periodicity is known as nocturnal periodicity. Example: Nocturnal
c. periodic microfilariae of W bancrofti, Brugia malayi and Brugia timori.
a. The microfilariae are present in greatest numbers in the peripheral blood during day hours.
b. This type of periodicity is known as diurnal periodicity. Example: Diurnal periodic Loa Loa.
Nocturnal sub-periodicity and diurnal sub - periodicity
a. The microfilariae are present in the peripheral blood continuously throughout the day and night with a slight increase in numbers during the afternoon and evening.
b. This type of periodicity is referred to as diurnal sub- periodic periodicity. Example: Sub-periodic W. bancroftii and B. malayi.
c. The periodicity is believed to be and adaptation by microfilariae to the biting habits of the mosquito vectors.