TEMA 13 - PHYLLUM APICOMPLEX, GENUS PLASMODIUM Flashcards
Life cycle
Bite of a mosquito, tissue phae; penetration in humans. When female bites, she inoculates the sprozoites (infetious forms) that go directly to the bloodstream and then penetrate into hepatic cells, starting liver phase.
Type of cycle
Di- heteroxenous life cycle, with the presence of an IH and an Iinvertabrate host, which is the female of Gns. Anopheles. The parasites from this genus are intracellular parasites of RBCs.
Different species
5 different humans species Plasmodium vivax Plasmodium malaria Plasmodiym falciparum Plasmodium ovale
Plasmodium vivax
It infects young RBCs, deforming and elarging them. Teo trophozoites enter in each RBC, adopting an ameboid shape when mature. Shizont appears tiwh 20 to 24 merozoites..RBCs that are infected will be full with granules called Schiiffner graanñues. Erytrhocytic shizogony appears every 48 h.
It produces a benign tertiary malaria, and this species appears in subtropical areas of Asia and Nrth Africa.
Plasmodium malaria
Infeced RBCs ramian the same size. Young and mature trophozoites adopt band shape. Granules are very smlall and cannot be seen, they are called Ziemann granules. Erythrocytic schizogony takes place every 72h so plasmodium roduces a benign quaternary malaria, cosmopolitan in tropical areas.
Plasmodium falciparum
Erytrhocyes of all types. A high nmber of RBCs are infected. It is possible to find trophozoites with more than 1 nucleus. Maurer granules, this granules are thick but not numerous.
Erytrhocytic schizogony is produced every 48 , it produes a malign tertiary mlalaria.
Subtropical areas of Africa , Asia and central America.
Plasmodium ovale
It affects young RBCs, that get deformed with oval shape. Infect of granules Schuffner granules. Granules larger thaan in Plasmodium vivax. Erythrocytic shizogony appears every 48 h, so it produces bening teritary malaria. It only appars in tropical Africa.
Plasmodium knowlesi
Similar to P. ovale but without evident granules
Transmission of Malaria
The vector is the female of Gns. Anopheles, mainly Anipheles gambiae, and Anopheles funestus. These vectors are endophilic, they lie to bite inside houses and present noctural activity, so they usually bite when we are sleeping. It presents an aquatic life cycl, threby they will only reproduce in areas with water reservoirs.
The most common mechanism of infection in humans is vector biting, but there are also antrhoponoti ways of infection like blood transfusion, congenital infection or by use of infected syringes.
Pathological actions of Malaria
Plunder action - they destroy RBCs
Irritative and toxic actions; the pigments and metabolites that they produce are irritative hemozoin produced is irritative and granules are pyrogens.
Mechanical action; they are able to poroduce clots or embolisms in capillaries.
Symptomatology; incubation period when the parasites are in the liver. Unspecific symptoms apear like headache or diarrhe. Then acut period, 3 typicla symptoms- classic accsss,; cold, heat and fever and sweating.
Acute phase
Int he case of P.vivax, P.ovale and P. malarie infections. Patients suffer frst anabrupt chill, appearing a lot of cold that last about 1 h. Accompaned by grinding teeth, gose bumps and shivering. Then fever, raching 41ºC and lasting more thatn 2 h. Then strong sweating 2 h.
Then this cycle is repeated
P. falciparum infectins
RBCs do not break all toghether at the ame time, they break unsyncrhonised and continuoslu, releasing pyrogenic substances that produce longer febrile episodes. Maling tertiary malaria.
Prasitised RBCs may modify its surface and present cyto-adherence. Clots, embolism , occluson and failure of several organs.
Chronic period in the case of plasmodium vivax and ovale
RECIDIVE FORMS - hypnozoites
Crhonic period in the case of Malaria and falciparum
RECRUDESCENCE Increase of parasitenia after the inmmune system of the host is weakened.
CHRNOIC PERIOD IN THE CAE OF OVALE, VIAX AND MALARIA
A progressive anemia is caused, leading to cathexia. In plasmodium malaria, quartan nephrosis. Children affected present a barrel shest and a pale, yellowish or grey slin.
