Tuesday, February 19, 2019


Life Cycle of plasmodium vivax (Malarial Parasite) Systematie Position Kingdom Protista Phylum Protozoa Class Sporozoa Genus plasmodium Species vivax Habit s and habitat- malaria parasite is an intra carrellular sporozoan parasite causing malaria in human being. The parasite lives in the erythrocytes and colored cells of man and alimentary fag endal and salivary glands of fe manful Anopheles mosquito. social organization- Structure of plasmodium is different stages of its life cycle. A fully grown malarial parasite is amoeboid and uninucleated structure know as trophozoite.Trophozoite is surrounded by double layered plasma lemma. Cytoplasm plights Palades granules, endoplasmic reticulum, ribosome, mitochondria, vesicles and vacuoles having haemozoin. Cytoplasm contains karyon having nucleolus and granular nucleoplasm. Life Cycle ofmalaria parasitevivax Hosts- plasmodium completes its lifecycle in two hosts (digenetic) military man and female Anop heles mosquito. 1. Primary or authorised host Female Anopheles mosquito is the primary host of Plasmodium in which it completes its knowledgeable life cycle. 2. Secondary or Intermediate host Man is the secondary host of plasmodium in which it completes its asexual life cycle.The lifecycle of Plasmodium can be divided into three phases 1. ve wee-weeative sehizogony 2. Sexual gamogony 3. nonsexual sporogony A inner CYCLE OF Plasmodium, IN MAN Infective melody of Plasmodium is known as sporozoites. Sporozoites be 11-12 long slender, uni-nucleated. Sickle-shaped structure set in the salivary glands of infected mosquito. When an infected female Anopheles mosquito bites a healthy man, a large consequence of sporozoites enter into the blood pepper of man. Within half an hour, sporozoites enter the liver cells and undergo asexual coevals called schizogony. 1. Asexual Schizogony-Schizogony is the asexual phase of reproduction of Plasmodium. It takes place in liver cells and RBCs of man. Schizogony can be divided into following phases a) Pre-erythrocytic schizogony b) Exo-erythrocytic schizogony c) Erythrocytic schizogony d) Post- erythrocytic schizogony a. Pre-erythrocytic schizogony In the liver cells, sporozoites grow to form a large and spherical schizont. Schizont divides by multiple fission and forms a large number of cryptozoites. They may all pass into the blood circulation to down erythrocytic schizogony or enter wise to(p) liver cells to start Exo-erythrocytic schizogony.Pre-erythrocytic schizogony takes 8 days to complete. b. Exo-erythrocytic schizogony aft(prenominal) re-entering fresh liver cell each cryptozoites divides to form a large number of metacryptozoites similar to pre-erythrocytic schizogony. Meta-cryptozoites are two types Smaller micro-metacryptozoites and larger macro-metacryptozoites. The micro-metacryptozoites enter the RBCs to start erythrocytic schizogony, while the macro-metacryptozoites invade fresh liver cells to continue e xo-erythrocytic schizogony. It takes normally 4 days to complete. c. Erythrocytic schizogony-As stated above, the erythrocytic schizogony begins when the RBCs of blood are attacked both by pre-erythrocytic cryptozoites or by exo-erythrocytic micro-metacryptozoites. It takes normally in 8 to 12 days afterwards above 2 phases. Stages of erythrocytic schizogony are i. Trophozoite Stage- The merozoites (cryptozoites and micro- metacryptozoites) after entering into the blood stream, feed on erythrocytes, become rounded and qualify into trophozoite. ii. Signet Ring Stage- As the merozoites grow a vacuole appears in the totality and the nucleus is pushed to one side.It gives a ring like port and known as signet ring stage. The parasite ingests haemoglobin and decomposes it into protein and haematin. Protein is use as nutrient whereas unused haematin forms nephrotoxic. Yellowish brown malarial pigment, haemozoin. iii. Amoeboid Stage As the signet ring parasite grows, vacuole disappe ars and the parasite becomes amoeboid in appearance, thrusting pop out pseudopodial processes. This stage is called amoeboid stage. At this stage RBC develops numerous granules, the Schuffners granules. iv. Schizont Stage- Parasite grows in size, becomes rounded and almost completely fills the RBC called Schizont. . Rosette Stage- The nucleus of schizont divides by multiple fission to form 6 to 24 female child nuclei. These nuclei arrange at the periphery, while the toxic haemozoin granules accumulate at the center of RBC. It appears as a flower rose, so called rosette stage. Nuclei of rosette stage are surrounded by a little cytoplasm and are develop into merozoites. With the rupture of the RBC, these merozoites are turn into the blood plasma along with toxic haemozoin. These normally attack fresh RBCs to repeat the erythrocytic cycle or may permute into gametocytes.One complete erythrocytic cycle takes 48 hours in Plasmodium vivax. d. Post-erythrocytic schizogony- Sometimes, s ome merozoites produced in erythrocytic schizogony reach the liver cells and undergo schizogony development in liver cells. This is called post-erythrocytic schizogony. SEXUAL CYCLE OF Plasmodium in MAN 2. Sexual Gamogony- Formulation of gametocytes After many generations in about 4-5 is the blood some merozoites increase in size to form two types of gametocytes larger macro (9-10), less numerous and contain large nucleus.Macro gametocytes are larger (10-12), more numerous and contain smaller nucleus. SEXUAL CYCLE OF Plasmodium IN MOSQUITO When a female Anopheles sucks the blood of a malaria enduring of, the gametocytes reach the die hard of mosquito and formation of gametes take palace as follows a. Gametogenesis (gemetogony) Process of formulation of gametes (male and female gametes). i. Formulation of male gametes The nucleus of microgametocyte divides to form 6-8 daughter nuclei. The cytoplasm gives out same number of flagella like projections and daughter nuclei enter in ea ch projection.These projections separate from the cytoplasm and form 6-8 monoploid microgamete or male gametes. This process of formation of microgamete is called exflagellation. ii. arrangement of female gamete- The mega gametocyte undergoes some reorganization to form a single haploid mega gamete or female gamete which is ready for fertilization. b. Fertilization The male gamete enters the female gamete done the fertilization cone formed at female gamete and form diploid zygote or synkaryon. Fusion is anisogamous. c. Ookinete stageThe zygote remains lazy for sometimes and then elongates into a worm like Ookinete or vermicule, which is motile. The Ookinete penetrates the stomach wall and comes to lie below its outer epithelial layer. d. Oocyst stage The Ookinete gets envelop in a cyst. The encysted zygote is called Oocyst. The Oocyst absorbs nourishment and grows in size. 3. Asexual Sporogony The nucleus of Oocyst divides repeatedly to form a large number of haploid daughter nu clei. At the same time, the cytoplasm develops vacuoles and gives numerous cytoplasmic masses.The daughter nuclei pass into each cytoplasmic mass and develop into slender curved sporozoites are formed in each Oocyst. This phase of asexual genesis is known as sporogony. Lastly, the Oocyet brusts and sporozoites are liberated into the haemolymph of the mosquito. They spread throughout the haemolymph and at long last reach the salivary glands and enter the duct of the hypopharyx. The mosquito is now becomes infective and sporozoites get inoculated or injected the human blood when the mosquito bites. The cycle is repeated. In mosquito whole sexual cycle is completed in 10-12 days.Incubation period The period between transmission system and the appearance of first symptoms is called incubation period. It is about 10-14 days in Plasmodium vivax. Pre-patent period The duration between the initial sporozoites infection and the first appearance of parasites in the blood is called as pre-p atent period. It takes about 8 days in Plasmodium vivax. Symptoms of malaria Mouth becomes dry, nausea and vent of appetite Headache, muscular infliction and joint pain Chill, fever (106 F) and sweating all every 48 hours. Chill to sweating lasts for 8-10 hours. Liver and spleen become enlarged. Due to loss of RBCs anaemia is caused. Control of malaria Malaria can be controlled by three ways 1. Destruction of vector 2. Prevention of infection(prophylaxis) 3. Treatment of patient 4. Public awareness 1. Destruction of vector (Anopheles mosquito) Mosquito can be killed by spraying DDT, BHC, Dieldrin, Malathion etc. Filling up ditches, gutters and pits where the mosquito breeds. Water surface can be poisoned by spreading kerosene oil, petroleum etc. A speedly flow of water prevents the mosquito larva and pupa flourishing. Biological control Certain fishes (trouts, minnows, stickle back), ducks, flying dragon flies etc feed on larva and pupa of mosquito. 2. Prevention of infe ction (Prophylaxis) Use of mosquito nets. masking piece doors, windows and ventilators. Using mosquito repellent creams (e. g. odomus), anti mosquito mat (e. g. Supermat) etc. 3. Treatment of patient There are several drugs that kill different stages of parasite in patient. The oldest drug is Quinine Paludrine kills almost all stages of parasite. Daraprism (single dose of 25 mg) is the most effectual drug.Write short note on Plasmodium falciparum Plasmodium falciparum causes malignant tertian type of malaria. Fever reccurs every second or third day, that is, after 36 to 48 hours. Death rate is very high because the infected red blood corpuscles tend to clump into masses, thus blocking up small blood vessels of internal organs, such as brain, spleen, lungs, etc. It is in addition known as the tropical epidemic malaria of man. Exo-erythrocytic schizogony is absent in P. falciparum. tell morehttp//www. hsebguides. com/2012/04/plasmodium-vivax-malarial-parasite. htmlixzz2G57xlaK6

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