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The sporozoites of Plasmodium enter the human bloodstream through
The sporozoites of Plasmodium enter the human bloodstream through
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Solution
The correct option is B the bite of a female Anopheles mosquito
Plasmodium is a protozoan microbe that causes malaria in humans. Plasmodium completes its life cycle in two different hosts, the female Anopheles mosquitoes (which are responsible for its transmission) and the humans.
Life cycle of the parasite as follows:
- The sporozoites are mature infective stages of Plasmodium that are present in the salivary glands of the infected mosquito.
- The sporozoites enter the human bloodstream when the female Anopheles mosquito bites an individual and injects its saliva into the bloodstream (step 1).
- These sporozoites attack the liver cells (step 2) where they undergo asexual reproduction (exoerythrocytic cycle) to produce and release multiple smaller parasitic structures called merozoites (step 3 and 4)
- These merozoites start attacking red blood cells (step 5) and multiply asexually (erythrocytic cycle) within them to produce more merozoites. Then some of the merozoites develop into a feeding stage known as a trophozoite.
- Trophozoite goes through many developmental stages and repeated nuclear divisions to form a schizont having 6-24 nuclei. New merozoites are formed when cytoplasmic divisions occur in the schizont. The merozoites rupture the red blood cells to be released into the blood. The released merozoites infect more red blood cells and the cycle continues (step 6).
- In some of the infected blood cells, the trophozoites develop into sexual forms called gametocytes, that circulate in the bloodstream (step 7).
- When a mosquito bites an infected human, it ingests the gametocytes which develop further into mature gametes within the gut of the mosquito (step 8).
- Zygotes formed due to fertilisation of gametes develop into motile ookinetes (step 9) that dig through the midgut wall of the mosquito and form oocysts (step 10) on the exterior surface.
- Oocysts eventually burst to release sporozoites (step 11) which travel to the mosquito's salivary glands and are transmitted to a human by mosquito bite.
Malaria is not transmitted through contaminated food and water or by direct contact.
Contaminated food and water transmit the pathogens of bacterial diseases such as cholera (Vibrio cholerae), typhoid (Salmonella typhi), protozoan disease such as amoebic dysentery (Entamoeba histolytica) etc.
Contact with an infected person can transmit diseases such as smallpox, chicken pox, common cold (Rhinovirus) etc.
Plasmodium is a protozoan microbe that causes malaria in humans. Plasmodium completes its life cycle in two different hosts, the female Anopheles mosquitoes (which are responsible for its transmission) and the humans.
Life cycle of the parasite as follows:
- The sporozoites are mature infective stages of Plasmodium that are present in the salivary glands of the infected mosquito.
- The sporozoites enter the human bloodstream when the female Anopheles mosquito bites an individual and injects its saliva into the bloodstream (step 1).
- These sporozoites attack the liver cells (step 2) where they undergo asexual reproduction (exoerythrocytic cycle) to produce and release multiple smaller parasitic structures called merozoites (step 3 and 4)
- These merozoites start attacking red blood cells (step 5) and multiply asexually (erythrocytic cycle) within them to produce more merozoites. Then some of the merozoites develop into a feeding stage known as a trophozoite.
- Trophozoite goes through many developmental stages and repeated nuclear divisions to form a schizont having 6-24 nuclei. New merozoites are formed when cytoplasmic divisions occur in the schizont. The merozoites rupture the red blood cells to be released into the blood. The released merozoites infect more red blood cells and the cycle continues (step 6).
- In some of the infected blood cells, the trophozoites develop into sexual forms called gametocytes, that circulate in the bloodstream (step 7).
- When a mosquito bites an infected human, it ingests the gametocytes which develop further into mature gametes within the gut of the mosquito (step 8).
- Zygotes formed due to fertilisation of gametes develop into motile ookinetes (step 9) that dig through the midgut wall of the mosquito and form oocysts (step 10) on the exterior surface.
- Oocysts eventually burst to release sporozoites (step 11) which travel to the mosquito's salivary glands and are transmitted to a human by mosquito bite.
Malaria is not transmitted through contaminated food and water or by direct contact.
Contaminated food and water transmit the pathogens of bacterial diseases such as cholera (Vibrio cholerae), typhoid (Salmonella typhi), protozoan disease such as amoebic dysentery (Entamoeba histolytica) etc.
Contact with an infected person can transmit diseases such as smallpox, chicken pox, common cold (Rhinovirus) etc.
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