1 / 15

Malarial life cycle…

Malarial life cycle…. Dr.Shelke A.N. Assist.professor Mrs.K.S.K.College,beed. Plasmodium specie which infect humans. Plasmodium vivax (tertian). Oocyst. Sporozoites. Mosquito Salivary Gland. Zygote. Hypnozoites (for P. vivax and P. ovale ). Gametocytes. Erythrocytic

gwendolynd
Download Presentation

Malarial life cycle…

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Malarial life cycle… Dr.Shelke A.N. Assist.professor Mrs.K.S.K.College,beed

  2. Plasmodium specie which infect humans Plasmodium vivax (tertian)

  3. Oocyst Sporozoites Mosquito Salivary Gland Zygote Hypnozoites (for P. vivax and P. ovale) Gametocytes Erythrocytic Cycle Malaria Life Cycle Life Cycle Sporogony Exo- erythrocytic (hepatic) cycle Schizogony

  4. Malaria Transmission Cycle Exo-erythrocytic (hepatic) Cycle: Sporozoites infect liver cells and develop into schizonts, which release merozoites into the blood Sporozoires injected into human host during blood meal Parasites mature in mosquito midgut and migrate to salivary glands Dormant liver stages (hypnozoites) of P. vivax and P. ovale HUMAN MOSQUITO Erythrocytic Cycle: Merozoites infect red blood cells to form schizonts Some merozoites differentiate into male or female gametocyctes Parasite undergoes sexual reproduction in the mosquito

  5. Components of the Malaria Life Cycle Sporogonic cycle Infective Period Mosquito bites uninfected person Mosquito Vector Parasites visible Human Host Mosquito bites gametocytemic person Symptom onset Prepatent Period Recovery Incubation Period Clinical Illness

  6. Exo-erythrocytic phase • Blood is infected with sporozoites about 30 minutes after the mosquito bite • The sporozoites are eaten by macrophages or enter the liver cells where they multiply – pre-erythrocytic schizogeny • P. vivax sporozoites form parasites in the liver called hypnozoites

  7. Oocyst Sporozoites Mosquito Salivary Gland Zygote Hypnozoites (for P. vivax and P. ovale) Gametocytes Erythrocytic Cycle Malaria Life Cycle Life Cycle Sporogony Exo- erythrocytic (hepatic) cycle Schizogony

  8. Exo-erythrocytic phase • P. vivax and P. ovale hypnozoites remain dormant for months • They develop and undergoe pre-erythrocytic sporogeny • The schizonts rupture, releasing merozoites and producing clinical relapse

  9. Erythrocytic phase • Pre-patent period – interval between date of infection and detection of parasites in peripheral blood • Incubation period – time between infection and first appearance of clinical symptoms • Merozoites from liver invade peripheral (RBC) and develop causing changes in the RBC • There is variability in all 3 of these features depending on species of malaria

  10. Erythrocytic phasestages of parasite in RBC • Trophozoites are early stages with ring form the youngest • Tropohozoite nucleus and cytoplasm divide forming a schizont • Segmentation of schizont’s nucleus and cytoplasm forms merozoites • Schizogeny complete when schizont ruptures, releasing merozoites into blood stream, causing fever • These are asexual forms

  11. Erythrocytic phasestages of parasite in RBC • Merozoites invade other RBCs and schizongeny is repeated • Parasite density increases until host’s immune response slows it down • Merozoites may develop into gametocytes, the sexual forms of the parasite

  12. Symptoms of malaria • Early symptoms • Headache • Malaise • Fatigue • Nausea • Muscular pains • Slight diarrhea • Slight fever, usually not intermittent • Could mistake for influenza or gastrointestinal infection

  13. Symptoms of malaria • Acute febrile illness, may have periodic febrile paroxysms every 48 – 72 hours with • Afebrile asymptomatic intervals • Tendency to recrudesce or relapse over months to years • Anemia, thrombocytopenia, jaundice, hepatosplenomegaly, respiratory distress syndrome, renal dysfunction, hypoglycemia, mental status changes, tropical splenomegaly syndrome

  14. Symptoms of malaria • Early symptoms • Headache • Malaise • Fatigue • Nausea • Muscular pains • Slight diarrhea • Slight fever, usually not intermittent • Could mistake for influenza or gastrointestinal infection

  15. Common features of P.vivax infections • Incubation period in non-immunes 12-17 days but can be 8-9 months or longer • Some strains from temperate zones show longer incubation periods, 250-637 days • First presentation of imported cases – 1 month – over 1 year post return from endemic area • Typical prodromal and acute symptoms • Can be severe • However, acute mortality is very low

More Related