Symptoms of malaria first appear several days after the infection of the malarial parasite in man:
i. Malaria infected patient suffers from periodical attack of high fever upto 104°F or more with chilliness and shivering which coincide with the liberation of merozoites.
ii. Malaria victim suffers from nausea, headache, muscular pain, joint pain, constipation etc.
iii. As the temperature lowers down, the fever of the patient subsides to normal along with profuse sweating.
iv. Malaria victim’s tongue becomes thickly coated and loss of appetite is seen.
v. In infection with Plasmodium species anaemia is inevitable due to destruction of RBC.
vi. In chronic cases, the patient develops a high enlargement of spleen.
vii. Liver is enlarged due to congestion of hepatic capillaries and hyperplasia of the Kupffer’s cells laden with pigment. The colour is chocolate brown in acute cases but in chronic cases it is slate grey or black. Kupffer’s cells are distended with haemozoin pigment. The left lobe of the liver is specially pigmented as it received blood from the spleen.
Pathogenicity:
Attack of fever (benign tertian type) takes place every 48 hrs. coinciding discharge of merozoites in blood stream on completion of an erythrocytic schizogonous cycle, starting with chill, followed by rise in temperature and lastly terminating in discharge of sweat. In case of P. vivax infection completion of erythrocytic schizogony occurs on alternate days.
Here anaemia and splenomegaly are prominent symptoms. The falciparum infection often results in thrombosis of visceral capillaries. Death is occurred when capillaries of brain become plugged with both the parasites and malarial pigment.
The very serious outcome of the falciparum infection is ‘black water fever’. This is manifested by the wholesale destruction of patient’s RBC and excretion of liberated haemoglobin in urine. Malignant malaria may also involve heart muscle causing infracts.