Malaria , types and control of Malaria

 

Malaria

Malaria is caused by a Protozoan Plasmodium vivax.It is a digenetic parasite because it completes its life cycle in two hosts. First host is Human and second is Female Anopheles.

  

Asexual phase of life cycle of plasmodium take place in Human whereas Sexual phase takes place in Mosquito. Due to the occurrence of sexual phase, Mosquito is regarded as the primary host.

Sexual phase of life cycle of plasmodium

When an infected Anopheles mosquito bites a healthy person then it introduces sporozoite in the body of the person. This sporozoite has a single nucleus and is covered by an elastic cuticle.These sporozoites make entry into the liver where they produce cryptozoite. Now these cryptozoites multiply asexually by the Schizogony and form crypto merozoites.

Crypto merozoite enter into new liver cells and produce asexually Meta crypto merozoites and micro crypto merozoite.

Out of these, Micro crypto merozoite enter into the blood stream and make target to Red blood cells. .Here these Micro crypto merozoites assume disc-like shape with single vacuole and give ring-like appearance.This stage is called signet ring stage.

Now parasites start to feed Red blood cells and assume amoeboid stage or trophozoite stage. The mature trophozoite develops into a Schizont. Schizont multiplies asexually by the erythrocytic schizogony. Schizont loses its pseudopodia and its nucleus divides to form a large number of merozoites . This stage is called the rosette stage.

Merozoite again makes entry in fresh RBC and produces more merozoite. During this stage,A chemical is also released  due to bursting of RBC called is responsible for chilling and high fever during Malaria.

 

Few merozoites produce two of gametocytes. Macro gametocyte and microgametocyte. Macro and micro gametocyte are considered as female and male gametocytes

Asexual phase of life cycle of plasmodium

When a female anopheles bites a patient of malaria , gametocytes are ingested by mosquito and reach in the stomach. Where macro and micro gametocytes are fused after the further development and a zygote is formed.

After some period of inactivity, Zygote is changed into ookinete stage and covered by a cyst. This stage undergoes  sporogony. In the sporogony, its nucleus divides repeatedly and forms a large number of sporozoite. After the bursting of cyst, sporozoite is liberated and stored in the salivary gland of the mosquito.

When Anopheles bites a healthy person sporozoite is injected into the body of the person and ready for the next life cycle.

 

Types of Malaria

Benign and tertian malaria caused by the P. Vivax in tropical and subtropical countries.

Quartan Malaria is caused by the P. malariae.

Overly and tertian malaria is caused by the P.ovale in West Africa and South America.

Malignant tertian malaria is caused by P.falciparum.It is most fatal and also called Percinious or Estivo Autumnal malaria.  

Control of Malaria 

It can be controlled by destroying  the secondary host .Mosquitoes can be killed by the spraying of pyrethrum and other insecticides at mosquito breeding places like pools, ditches and drains . The larva of mosquitoes can be killed by the larvicides..

Antimalarial drugs Quinine, Darapine, paludrine are used to kill sporozoite stage before development .

Some natural enemies like GAMBUSIA fish  are introduced in mosquito inhabiting place under the Biological control.