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What is pre-erythrocytic Schizogony?
It's the asexual phase in the malaria life cycle that takes place in the liver.
Distinguish between the pre-erythrocytic and erythrocytic stages in the life cycle of the malarial parasite?
The pre-erythrocytic is the gliding and hiding of the parasite and will occur before you notice any changes. The erythrocytic is when the parasite grows and you notice symptoms.
What is a schizont?
A sporozoan cell created by the process of schizogony.
How do amoebas differ from sporozoan in the way they reproduce?
Amoeba reproduces by binary fission while sporozoans show schizogony , sporogony , gametogony and syngamy .
What has the author R S Bray written?
R. S. Bray has written: 'Studies on the exo-erythrocytic cycle in the genus Plasmodium' 'Armies of Pestilence the Impact of Disease'
Describe the developmental stages of the malarial parasite during sporogamy and schizogony?
SporogonyThe Anopheles mosquito ingests malarial parasites when it feeds on an infected human. In the mosquito's stomach, the parasites move to the gut wall, where they reproduce asexually through the process of sporogony, and produce an oocyst, or spore. These oocysts eventually burst, releasing sporozoites that travel through the mosquito's body to its salivary glands, and finally to its central salivary duct.SporozoitesWhen a carrier mosquito drinks human blood, the malarial sporozoites travel through its saliva to the host's blood stream, and quickly make their way to the liver's functional cells. The parasites can also infect red blood cells, causing fever, anemia and -- in some cases -- death.SchizogonySchizogony is a form of asexual reproduction in which the multiple fission of sporozoites produces merozoites that can reproduce sexually or asexually. This process often begins as soon as the parasites enter their vertebrate host. For example, Plasmodium falciparum and P. malariae begin reproducing immediately. However, P. ovale and P. vivax may delay reproduction, by forming hypnozoites that remain dormant in the liver cells. P. vivax hypnozoites can have a dormancy of up to 10 months, whereas P. falciparum and P. malariae do not create hypnozoites at all.MerozoitesPre-erythrocytic schizogony occurs in the host's liver cells before the parasite invades red blood cells (erythrocytes). During this phase, each sporozoite produces multiple merozoites, which consist of a single nucleus encased in a narrow cytoplasmic ring. Each P. ovale sporozoite produces 15,000 merozoites. P. vivax produces 10,000, P. falciparum produces 40,000 and P. malariae produces 2,000. Merozoites typically invade red blood cells within two minutes of life.
What is the medical term meaning substance that forms red blood cells?
Erythrocyte is the medical term meaning mature red blood cell. In medical terminology Erythro = red, cytes= cells.Associated term:White blood cells are called Leukocytes, Leuko = white, cytes = cells.
How does plasmodium vivax?
sexual reproduction takes place in plasmodim vivax.after the erythrocytic phase some merozoites on entering the RBC develop into sexually differentiating forms called gamatocytes.these are two types male gamatocytes and female gamatocytes.when female anapheles mosquito bites a person suffering from malaria these gamatocytes enter into the crop of the mosquito.in malegamatocyte the nucleus divide into 8 daughter nuclei and 8 flagellated processes appear on the cytoplasm.each nuclear bit passes into each of these cytoplasmic extentionsand forms a male gamate.this process is called exflagellation. femalegamatocyte undergo maturation to form female gamate.the nucleus moves towards pheriphery and cytoplasm forms a projection at that point.this projection is called fertilisation cone.fertilisation;the malegamate keep on actively lashing movement.one of these come in contact with the fertilisation cone of female gamate and enter into it.the pronucleus of male gamate fuses with female gamate.as fusing gamates are dissimilar in form this fusion is described as anisogamy.this result's in fomation of spherical zygote.so plasmodium vivax reproduces sexually
Do Plasmodium reproduce through multiple fission or sporulation?
sexual reproduction takes place in plasmodim vivax.after the erythrocytic phase some merozoites on entering the RBC develop into sexually differentiating forms called gamatocytes.these are two types male gamatocytes and female gamatocytes.when female anapheles mosquito bites a person suffering from malaria these gamatocytes enter into the crop of the mosquito.in malegamatocyte the nucleus divide into 8 daughter nuclei and 8 flagellated processes appear on the cytoplasm.each nuclear bit passes into each of these cytoplasmic extentionsand forms a male gamate.this process is called exflagellation. femalegamatocyte undergo maturation to form female gamate.the nucleus moves towards pheriphery and cytoplasm forms a projection at that point.this projection is called fertilisation cone.fertilisation;the malegamate keep on actively lashing movement.one of these come in contact with the fertilisation cone of female gamate and enter into it.the pronucleus of male gamate fuses with female gamate.as fusing gamates are dissimilar in form this fusion is described as anisogamy.this result's in fomation of spherical zygote.so plasmodium vivax reproduces sexually
What is the life cycle of plasmodium?
Schema of the Life Cycle of Malaria= = The malaria parasite life cycle involves two hosts. During a blood meal, a malaria-infected female Anopheles mosquito inoculates sporozoites into the human host . Sporozoites infect liver cells and mature into schizonts , which rupture and release merozoites . (Of note, in P. vivax and P. ovale a dormant stage [hypnozoites] can persist in the liver and cause relapses by invading the bloodstream weeks, or even years later.) After this initial replication in the liver (exo-erythrocytic schizogony ), the parasites undergo laughl multiplication in the erythrocytes (erythrocytic schizogony ). Merozoites infect red blood cells . The ring stage trophozoites mature into schizonts, which rupture releasing merozoites . Some parasites differentiate into sexual erythrocytic stages (gametocytes) . Blood stage parasites are responsible for the clinical manifestations of the disease. The gametocytes, male (microgametocytes) and female (macrogametocytes), are ingested by an Anopheles mosquito during a blood meal . The parasites' multiplication in the mosquito is known as the sporogonic cycle . While in the mosquito's stomach, the microgametes penetrate the macrogametes generating zygotes . The zygotes in turn become motile and elongated (ookinetes) which invade the midgut wall of the mosquito where they develop into oocysts . The oocysts grow, rupture, and release sporozoites , which make their way to the mosquito's salivary glands. Inoculation of the sporozoites into a new human host perpetuates the malaria life cycle. ANSWERED BY: GENERAL PROFESSOR ARIEL N. MAGNO MALARIA: A SERIOUS DISEASE by: GENERAL PROFFESOR ARIEL MAGNO of CEBU,PHILIPPINES. In nature, malaria parasites spread by infecting successively two types of hosts: humans and female Anophelesmosquitoes. In humans, the parasites grow and multiply first in the liver cells and then in the red cells of the blood. In the blood, successive broods of parasites grow inside the red cells and destroy them, releasing daughter parasites ("merozoites") that continue the cycle by invading other red cells. The blood stage parasites are those that cause the symptoms of malaria. When certain forms of blood stage parasites ("gametocytes") are picked up by a female Anopheles mosquito during a blood meal, they start another, different cycle of growth and multiplication in the mosquito. After 10-18 days, the parasites are found (as "sporozoites") in the mosquito's salivary glands. When the Anopheles mosquito takes a blood meal on another human, the sporozoites are injected with the mosquito's saliva and start another human infection when they parasitize the liver cells. Thus the mosquito carries the disease from one human to another (acting as a "vector"). Differently from the human host, the mosquito vector does not suffer from the presence of the parasites. View Schema of the life cycle of malaria = Human Hosts = Humans infected with malaria parasites can develop a wide range of symptoms. These vary from asymptomatic infections (no apparent illness), to the classic symptoms of malaria (fever, chills, sweating, headaches, muscle pains), to severe complications (cerebral malaria, anemia, kidney failure) that can result in death. The severity of the symptoms depends on several factors, such as the species (type) of infecting parasite and the human's acquired immunity and genetic background. more: Human Hosts = Malaria Parasites = Four species of malaria parasites can infect humans under natural conditions: Plasmodium falciparum, P. vivax, P. ovale and P. malariae. The first two species cause the most infections worldwide. Plasmodium falciparum is the agent of severe, potentially fatal malaria, causing an estimated 700,000 - 2.7 million deaths annually, most of them in young children in Africa. Plasmodium vivax and P. ovale have dormant liver stage parasites ("hypnozoites") which can reactivate ("relapse") and cause malaria several months or years after the infecting mosquito bite. Plasmodium malariae produces long-lasting infections and if left untreated can persist asymptomatically in the human host for years, even a lifetime. More: Malaria Parasites = Anopheles Mosquitoes = Malaria is transmitted among humans by female mosquitoes of the genus Anopheles. Female mosquitoes take blood meals to carry out egg production, and such blood meals are the link between the human and the mosquito hosts in the parasite life cycle. Of the approximately 430 known species of Anopheles, only 30-50 transmit malaria in nature. The successful development of the malaria parasite in the mosquito (from the "gametocyte" stage to the "sporozoite" stage) depends on several factors. The most important is ambient temperature and humidity (higher temperatures accelerate the parasite growth in the mosquito) and whether the Anopheles survives long enough to allow the parasite to complete its cycle in the mosquito host ("sporogonic" or "extrinsic" cycle, duration 10 to 18 days). Differently from the human host, the mosquito host does not suffer noticeably from the presence of the parasites. by:ariel n. magno pisti MALARIA: A SERIOUS DISEASE by: GENERAL PROFFESOR ARIEL MAGNO of CEBU,PHILIPPINES.In nature, malaria parasites spread by infecting successively two types of hosts: humans and female Anopheles mosquitoes. In humans, the parasites grow and multiply first in the liver cells and then in the red cells of the blood. In the blood, successive broods of parasites grow inside the red cells and destroy them, releasing daughter parasites ("merozoites") that continue the cycle by invading other red cells. The blood stage parasites are those that cause the symptoms of malaria. When certain forms of blood stage parasites ("gametocytes") are picked up by a female Anopheles mosquito during a blood meal, they start another, different cycle of growth and multiplication in the mosquito. After 10-18 days, the parasites are found (as "sporozoites") in the mosquito's salivary glands. When the Anopheles mosquito takes a blood meal on another human, the sporozoites are injected with the mosquito's saliva and start another human infection when they parasitize the liver cells. Thus the mosquito carries the disease from one human to another (acting as a "vector"). Differently from the human host, the mosquito vector does not suffer from the presence of the parasites. View Schema of the life cycle of malaria = Human Hosts = Humans infected with malaria parasites can develop a wide range of symptoms. These vary from asymptomatic infections (no apparent illness), to the classic symptoms of malaria (fever, chills, sweating, headaches, muscle pains), to severe complications (cerebral malaria, anemia, kidney failure) that can result in death. The severity of the symptoms depends on several factors, such as the species (type) of infecting parasite and the human's acquired immunity and genetic background. more: Human Hosts = Malaria Parasites = Four species of malaria parasites can infect humans under natural conditions: Plasmodium falciparum, P. vivax, P. ovale and P. malariae. The first two species cause the most infections worldwide. Plasmodium falciparum is the agent of severe, potentially fatal malaria, causing an estimated 700,000 - 2.7 million deaths annually, most of them in young children in Africa. Plasmodium vivax and P. ovale have dormant liver stage parasites ("hypnozoites") which can reactivate ("relapse") and cause malaria several months or years after the infecting mosquito bite. Plasmodium malariae produces long-lasting infections and if left untreated can persist asymptomatically in the human host for years, even a lifetime. More: Malaria Parasites = Anopheles Mosquitoes = Malaria is transmitted among humans by female mosquitoes of the genus Anopheles. Female mosquitoes take blood meals to carry out egg production, and such blood meals are the link between the human and the mosquito hosts in the parasite life cycle. Of the approximately 430 known species of Anopheles, only 30-50 transmit malaria in nature. The successful development of the malaria parasite in the mosquito (from the "gametocyte" stage to the "sporozoite" stage) depends on several factors. The most important is ambient temperature and humidity (higher temperatures accelerate the parasite growth in the mosquito) and whether the Anopheles survives long enough to allow the parasite to complete its cycle in the mosquito host ("sporogonic" or "extrinsic" cycle, duration 10 to 18 days). Differently from the human host, the mosquito host does not suffer noticeably from the presence of the parasites.Stage 1: After getting injected into the human bloodstream following a bite from Anopheles mosquito, the parasites in the form of sporozoites invade the liver. They stay in the liver cells after destroying them.Stage2: Over a period of 5 to 16 days, depending on the species of the malaria parasite, sporozoites multiply rapidly to create thousands of red blood cell invading parasites called merzoites. Each of the sporozoit infected liver cell creates thousands of merzoites. Some species of the malaria parasite remain dormant for long periods before causing relapses weeks or months later.Stage 3: The merzoites now leave the liver cells and invade the red blood cells after entering the bloodstream. In the next 1 to 3 days, asexual replications of merzoites take place leading to the sickness and complications of malaria. These symptoms can last for months if not treated. In the following stages of lifecycle of malaria parasite, it is explained how malaria spreads to other persons.Stage 4: A few of the red blood cells infected with merzoites stop replicating asexually and instead become male or female gametocyte (formations that develop into male or female parasite). These gametocytes start circulating in the bloodstream.Stage 5: When a mosquito bites an infected person with gametocytes circulating in his blood, it ingests them. They go on to develop into mature sex cells called gamete. Male and female gametes combine to form what is called an oocyst.Stage 6: In the last stage of the malaria parasite lifecycle, each of these oocysts forms several sporozoites in the body of the mosquito and reach its salivary glands. These sporozoites are again injected into the human blood when the mosquito bites and re-starts the whole cycle.
Ham test?
DefinitionThe Ham test is done to diagnose paroxysmal nocturnal hemoglobinuria (PNH). The test checks whether red blood cells become more fragile when they are placed in mild acid.Alternative NamesAcid hemolysin testHow the test is performedBlood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.How to prepare for the testThere is no special preparation needed for this test.How the test will feelWhen the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.Why the test is performedA positive test can confirm the diagnosis of PNH.The Ham test can also be used to diagnose another rare disorder called congenital dyserythropoietic anemia.Normal ValuesA negative test is normal.What abnormal results meanAbnormal results may be due to:Paroxysmal nocturnal hemoglobinuriaCongenital dyserythropoietic anemiaWhat the risks areThere is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.Other risks associated with having blood drawn are slight but may include:Excessive bleedingFainting or feeling light-headedHematoma (blood accumulating under the skin)Infection (a slight risk any time the skin is broken)Special considerationsThe HAM test is increasingly being replaced by a newer test called flow cytometry.ReferencesElghetany M, Banki K. Erythrocytic disorders. In: McPherson R, Pincus M, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 31.Schwartz R. Autoimmune and intravascular hemolytic anemias. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 164.
What is Plasmodium falciparum?
Plasmodium is a genus of parasitic protozoa. Infection with these parasites is known as malaria. The genus Plasmodium was created in 1885 by Marchiafava and Celli. Currently over 200 species in this genus are recognized and new species continue to be described.[1] [2] Of the 200+ known species of Plasmodium, at least 10 species infect humans. Other species infect animals, including birds, reptiles and rodents. The parasite always has two hosts in its life cycle: a mosquito vector and a vertebrate host. The genus is currently (2006) in need of reorganization as it has been shown that parasites belonging to the genera Haemocystis and Hepatocystis appear to be closely related to Plasmodium. It is likely that other species such as Haemoproteus meleagridis will be included in this genus once it is revised. Life Cycle Mosquitoes of the genera Culex, Anopheles, Culiceta, Mansonia and Aedes may act as vectors. The currently known vectors for human malaria (> 100 species) all belong to the genus Anopheles. Bird malaria is commonly carried by species belonging to the genus Culex. Only female mosquitoes bite. Aside from blood both sexes live on nectar, but one or more blood meals are needed by the female for egg laying as the protein content of nectar is very low. The life cycle of Plasmodium was discovered by Ross who worked with species from the genus Culex. The life cycle of Plasmodium is complex. Sporozoites from the saliva of a biting female mosquito are transmitted to either the blood or the lymphatic system [3] of the recipient. The sporozoites then migrate to the liver and invade hepatocytes. This latent or dormant stage of the Plasmodium sporozoite in the liver is called the hypnozoite. The development from the hepatic stages to the erythrocytic stages has until very recently been obscure. In 2006[4] it was shown that the parasite buds off the hepatocytes in merosomes containing hundreds or thousands of merozoites. These merosomes have been subsequently shown[5] to lodge in the pulmonary capilaries and to slowly disintegrate there over 48-72 hours releasing merozoites. Erythrocyte invasion is enhanced when blood flow is slow and the cells are tightly packed: both of these conditions are found in the alveolar capilaries. Within the erythrocytes the merozoite grow first to a ring-shaped form and then to a larger trophozoite form. In the schizont stage, the parasite divides several times to produce new merozoites, which leave the red blood cells and travel within the bloodstream to invade new red blood cells. The parasite feeds by ingesting haemoglobin and other materials from red blood cells and serum. The feeding process damages the erythrocytes. Details of this process have not been studied in species other than Plasmodium falciparum so generalisations may be premature at this time. At the molecular level a set of enzymes known as plasmepsins which are aspartic acid proteases are used to degrade hemoglobin. The parasite digests 70-80% of the erythrocyte's haemoglobin [6] but utilises only ~15% in de novo protein synthesis [7] The excess amino acids are exported from the infected erythorocyte by new transport pathways created by the parasite. [8] The reason proposed for this apparently excessive digestion of haemoglobin is the colloid-osmotic hypothesis [9] which suggests that the digestion of haemoglobin increases the osmotic pressure within the infected erythrocyte leading to its premature rupture and subsequent death of the parasite. To avoid this fate much of the haemoglobin is digested and exported from the erythrocyte. This hypothesis has been experimentally confirmed. [10] Most merozoites continue this replicative cycle, but some merozoites differentiate into male or female sexual forms (gametocytes) (also in the blood), which are taken up by the female mosquito. In the mosquito's midgut, the gametocytes develop into gametes and fertilize each other, forming motile zygotes called ookinetes. The ookinetes penetrate and escape the midgut, then embed themselves onto the exterior of the gut membrane. Here they divide many times to produce large numbers of tiny elongated sporozoites. These sporozoites migrate to the salivary glands of the mosquito where they are injected into the blood and subcutaneous tissue of the next host the mosquito bites. The majority appear to be injected into the subcutaneous tissue from which they migrate into the capillaries. A proportion are ingested by macrophages and still others are taken up by the lymphatic system where they are presumably destroyed. The sporozoites which successfully enter the blood stream move to the liver where they begin the cycle again. The pattern of alternation of sexual and asexual reproduction which may seem confusing at first is a very common pattern in parasitic species. The evolutionary advantages of this type of life cycle were recognised by Mendel. Under favourable conditions asexual reproduction is superior to sexual as the parent is well adapted to its environment and its descendents share these genes. Transferring to a new host or in times of stress, sexual reproduction is generally superior as this produces a shuffling of genes which on average at a population level will produce individuals better adapted to the new environment. Reactivation of the hypnozoites has been reported for up to 30 years after the initial infection in humans. The factors precipating this reactivation are not known. In the species Plasmodium malariae, Plasmodium ovale and Plasmodium vivax hypnozoites have been shown to occur. Reactivation was not thought to occur in infections with Plasmodium falciparum but there are been two reports to date suggesting that this may occur (see below) . It is not known if hypnozoite reactivaction may occur with any of the remaining species that infect humans but this is presumed to be the case. A report of recurrence of P. falciparum in a patient with sickle cell anaemia has been published [11] but this needs confirmation as hypnozoites are not known to occur in P. falciparum infections. A second report of P. falciparum malaria eight years after leaving an endemic area has also been published.[12] While this is consistent with the existence of a hypnozoite stage additional confirmation seems desirable.
