Department of microbiology & immunologyFaculty of pharmacyAin-Shams universityPlasmodium falciparumAya Ahmed Saber yosif86
Introduction:* Malaria is caused by one of four species of Plasmodium (falciparum, vivax, malariaeand ovale).*Of these P. falciparum is the most lethal being estimated to cause 200 million clinical cases, and 1-3 million deaths (including many children) every year world-wide*Plasmodium falciparum:*is a protozoan parasite, one of the species of Plasmodium that cause malaria inhumans.*It is transmitted by the female Anopheles mosquito.*also called malignant* is the most dangerous form of malaria with the highest rates of complications andmortality.*As of 2006 there were an estimated 247 million human malarial infections (98% inAfrica, 85% being 5 years or younger).[4* It is much more prevalent in sub-Saharan Africa than in other regions of the world; inmost African countries, more than 75% of cases were due to P. falciparum, whereas inmost other countries with malaria transmission, other less virulent Plasmodial speciespredominate. Almost all global malarial deaths are caused by P. falciparum.
History*The organism itself was first seen by Laveran on November 6, 1880 at a militaryhospital in Constantine, Algeria, when he discovered a microgametocyte exflagellating.*In 1885, similar organisms were discovered within the blood of birds in Russia. Therewas brief speculation that birds might be involved in the transmission of malaria.*in 1894 Patrick Manson hypothesized that mosquitoes could transmit malaria. Thishypothesis was independently confirmed by the Italian physician Giovanni BattistaGrassi working in Italy and the British physician Ronald Ross working in India, both in1898.*Ross demonstrated the existence of Plasmodium in the wall of the midgut and salivaryglands of a Culex mosquito using bird species as the vertebrate host.* For this discovery he won the Nobel Prize in 1902.*Grassi showed that human malaria could only be transmitted by Anophelesmosquitoes.
Pathogenesis*Plasmodium falciparum causes severe malaria via a distinctive property not shared byany other human malaria, that of sequestration.* Within the 48-hour asexual blood stage cycle, the mature forms change the surfaceproperties of infected red blood cells causing them to stick to blood vessels (a processcalled cytoadherence).*This leads to obstruction of the microcirculation and results in dysfunction of multipleorgans, typically the brain in cerebral malaria. Clinical picture ( Symptoms )*Malarial attacks present over 4 to 6 hours with shaking chills, high fever, and sweating,and are often associated with fatigue, headache, dizziness, nausea, vomiting, abdominalcramps, dry cough, muscle or joint pain, and back ache.*The attacks may occur every other day or every third day*Cerebral malaria and death can occur, sometimes within 24 hours, if the infection iscaused by plasmodium falciparum . Diagnosis of Malaria Methods of diagnosis are1-complete medical history of symptoms and travel2-physical examination3-blood tests, including: thick and thin blood films, to identify the plasmodium speciesresponsible for infection and for detection of schizonts,gametocytes& ring stage
Plasmodium life cycleThe life cycle of all Plasmodium species is complex.1- Infection in humans begins with the bite of an infected female Anopheline mosquito.2-Sporozoites released from the salivary glands of the mosquito enter the bloodstreamduring feeding, quickly invading liver cells (hepatocytes).3-Sporozoites are cleared from the circulation within 30 minutes.4- During the next 14 days in the case of P. falciparum, the liver-stage parasitesdifferentiate and undergo asexual multiplication resulting in tens of thousands ofmerozoites which burst from the hepatocyte.5-Individual merozoites invade red blood cells (erythrocytes) and undergo an additionalround of multiplication producing 12-16 merozoites within a schizont. The length of thiserythrocytic stage is 48 hours for P. falciparum (((The clinical manifestations ofmalaria, fever and chills, are associated with the synchronous rupture of the infectederythrocyte))).6- The released merozoites go on to invade additional erythrocytes.7- Not all of the merozoites divide into schizonts, some differentiate into sexual forms,male and female gametocytes.7-These gametocytes are taken up by a female anophylean mosquito during a bloodmeal.8- Within the mosquito midgut, the male gametocyte undergoes a rapid nuclear division,producing 8 flagellated microgametes which fertilize the female macrogamete.9- The resulting ookinete traverses the mosquito gut wall and encysts on the exterior ofthe gut wall as aoocyst.10-Soon the oocyst ruptures, releasing hundreds of sporozoites into the mosquito bodycavity where they eventually migrate to the mosquito salivary gland
MorphologyThe stages of malaria or falciparum malaria encountered in the humanA) Exo-erythrocytic stages Blood stages1-Sporozoites 5-merozoitesenters hepatocytes of liver enter erythrocytes2-schizonts 6-trophozoitesdividing forms of liver stages feeding and growing stages in red cells3-merozoites 7-schizontsare released by hepatocytes multinuclear stages in red cells4-hypnozoites 8-gametocytesresting liver stages sexual blood stages
Prevention Prevention is based on1-evaluating the risk of exposure to infection2-preventing mosquito bites by using DEET mosquito repellant, bed nets, and clothingthat covers most of the body3-chemoprophylaxis (preventive medications ) Treatment*Drugs include: chloroquine, mefloquine,pyrimethamine-sulfadoxine ,and combinationbetween Atovaqine&Proguani in case of resistance against chloraquine Drugs in the Egyption markets1-Cidoquine ( Cid)2-Chloraquine ( Pharco)3-Alexoquine(Pharco)4-Jedcoquine(Jedco)5-Malarquine(Nasr)6-Daraprim(Wellcome)7-Malariquin(EvaPharma)
Referenceshttp://www.healthscout.com/ency/68/347/main.html#TreatmentofMalariahttp://www.google.com.eg/search?q=plasmodium&hl=ar&rlz=1C1RNPN_enEG431&prmd=imvnsb&tbm=isch&tbo=u&source=univ&sa=X&ei=vJjeTpCyA8eSOurM_asJ&ved=0CEEQsAQ&biw=1280&bih=699http://en.wikipedia.org/wiki/Plasmodium_falciparum#Pathogenesishttp://www.jstor.org/pss/27802107http://www.jimmunol.org/content/149/1/194.shortMaster On Therapeutic Drugs( drug Index )Sief pharmacy