| SPECIES
OF PARASITE |
Malaria
in man is caused by 4 distinct species of malaria parasite -
1. Plasmodium vivax
2.
Plasmodium falciparum
3.
Plasmodium malariae
4. Plasmodium
ovale |
| Plasmodium
vivax |
It has
the widest geographic distribution throughout the world and
causes much debilitating disease.
In India, about 60% of the infections are due to P. vivax. |
| Plasmodium
falciparum |
It is
also wide spread, results in the most severe infections and
is responsible for nearly all malaria-related deaths.
40% of infection is due to P. falciparum. |
| Plasmodium
malariae |
| It has
restricted distribution and is said to be responsible for less
than 1% of infections in India |
| Plasmodium
ovale |
It is
very rare parasite of man, mostly confined to tropical Africa.
In highly endemic areas, the patient may become infected with
one, two or even more species of the malarial parasite.
In India, 4-8% is due to mixed infection. |
| Differentiating
features of P.vivax and P.falciparum malaria |
| Sr.No. |
P. vivax
|
P. falciparum |
| 1. |
P. vivax is relatively benign and
rarely produces serious complications or death
|
P. falciparum on the other hand, is associated
with serious complications e.g. cerebral malaria,
jaundice, renal failure etc. including high mortality |
| 2. |
In P. vivax, relapse occurs due to
persistence of inactive forms (hypnozoites) in liver tissues
which periodically invade blood stream producing clinical
malaria.
|
P. falciparum does not have any dormant
form in liver and once infection is cured, there is no
relapse.
|
| 3. |
In P. vivax malaria, less than 1% of
RBCs are parasitised |
In P. falciparum, the number of RBCs
involved may go upto 35%. |
| 4. |
The gametocytes (sexual stage) –
male and female mature in peripheral blood and
are sucked up by female anopheles mosquito for completion
of their life cycle |
For maturation of gametocyte P. falciparum
must invade deeper circulation. The blood capillaries
of internal organs get clogged with infected RBC thus
obstructing flow of blood. Also some biochemical changes
take place which damage the organ |
|
| Other
Modes of Transmission of Malaria |
| Malaria
can be transmitted by |
- Blood transfusion
- Needle- stick injury
- Sharing of needle by infected drug addicts
|
