1. Phylum Apicomplexa – Chapters 8 & 9 Phylum Apicomplexa consists of 4 groups of protozoan parasites: 1. 2. 3. 4. We will examine the first 3 groups, as they contain many parasites of medical and veterinary importance. We will omit the gregarines as they are parasites of invertebrates and are not important.

2. Characteristics of the Phylum Apicomplexa 1. ______________________________________________________________ 2. Possess _______________________________________________________ - these organelles are concentrated at _______________________________ - function? ____________________________________ - see diagram in text p. 124 3. _______________________________________ 4. _______________________________________ - alternation of _____________________________ - hosts?

3. Plasmodium and Malaria – Chapter 9 Malaria is one of the most important diseases of mankind. It has played an important part in the rise and fall of nations and has killed untold millions of persons. Today, __________________________are infected with malaria 1.5 billion people (2/3 of the world's population) live in endemic areas and are potential hosts. Malaria kills _____________________ people each year.

7. Life Cycle of Plasmodium The life cycle is complex, so we will go through it step by step to understand it.

16. Some Stages of Malaria in Anopheles Feeding female Anopheles Exflagellation showing microgametes Oocysts on outside of mosquito stomach Sporozoites from salivary gland

17. Some Stages of Malaria in the human Cryptozoite in liver cell – it will burst releasing merozoites Schizont – multinucleate form in rbc Trophozoite – uninucleate form in rbc Gametocyte – uninucleate form in rbc

19. Plasmodium falciparum distribution (2005) Plasmodium vivax distribution (2005)

20. Plasmodium vivax – stages in human blood Ring-stage Trophozoite - ________________________________________________________________ - cannot distinquish from other species Mature Trophozoite - trophozoite ____________________ - ______________________________ due to ameboid movement of parasite - reddish ______________________ appear (diagnostic!)

23. Plasmodium ovale – stages in human blood Ring-stage Trophozoite - nucleus and thin ring of cytoplasm - cannot distinquish from other species Mature Trophozoite - trophozoite ________________________ - reddish __________________________ appear (diagnostic!)

25. Plasmodium malariae Causes _________________________________ - quartan indicates a ______________________ erythrocytic cycle Occurs throughout the tropics but has a discontinuous distribution Also occurs in chimpanzees but is not considered a zoonosis as wild chimps and humans do not live together in nature for disease transmission to occur between them Relapse? ______________________________________________________ A human can be infected for many years with no apparent symptoms, and the parasite can suddenly become pathogenic. This phenomenon is called __________________________________. Fatalities are not uncommon. Is responsible for ___________% of world's malaria.

26. Plasmodium malariae – stages in human blood Ring-stage Trophozoite - nucleus and thin ring of cytoplasm - cannot distinquish from other species Mature Trophozoite - trophozoite often forms a __________________ across the rbc (diagnostic!) - trophozoite does not enlarge rbc - no Schuffner’s dots

29. Plasmodium falciparum distribution (2005) Plasmodium vivax distribution (2005)

35. History of Malaria Two Italians ____________________________________ (1898) experimentally transmitted malaria from mosquitoes to humans . It was not until 1948 that the complete life cycle was known when the pre-erythrocytic and exo-erythrocytic stages were found in the liver of infected humans by ________________________________ .

37. Pathology of Malaria Infections During the pre-erythrocytic and exo-erythocytic cycles in the liver , there is no pathology and no symptoms. Why? ___________________________________________________ Pathology of all 4 species occurs during the erythrocytic cycle by the synchronous rupture of schizonts and release of merozoites which destroy erythrocytes .

39. Pathological Differences among the 4 species Plasmodium vivax and Plasmodium ovale In vivax and ovale malaria, merozoites primarily invade __________________________ These malarias rarely cause death but make a person quite ill during a malarial paroxysm.

40. Pathological Differences among the 4 species Plasmodium vivax and Plasmodium ovale Paroxysm lasts ________________ and represents the time from invasion of rbc’s by merozoites until new merozoites are produced (length of erythrocytic cycle)

42. Plasmodium vivax and Plasmodium ovale pathology Most individuals recover from these infections and the parasites are __________________________ . Generally, the immune system totally eliminates the parasites after about 8 years.

43. Plasmodium malariae pathology In quartan malaria, merozoites of Plasmodium malariae primarily invade _________________________. There is no exo-erythrocytic cycle , so all the merozoites formed from cryptozoites invade rbc’s after the pre-erythrocytic incubation (no relapse). Malarial paroxysms occur every __________________ and represent the time from merozoite invasion of rbc’s to the formation of new merozoites (length of erythrocytic cycle).

45. Plasmodium falciparum pathology Falciparum malaria is the most serious of the 4 species, usually resulting in a fatality. Remember that only the ring-stage trophozoites and gametocytes are found in peripheral blood – mature trophozoites and schizonts are in rbc’s of the spleen and bone marrow. There is _____________________________________ , so all merozoites from the liver enter rbc’s - ______________________

46. Plasmodium falciparum pathology The erythrocytic cycle lasts from ______________ hours. Malarial paroxysm is unusual: ____________________________ _____________________________________________________

48. Plasmodium falciparum pathology 5. Massive rbc destruction results in high levels of hemoglobin removed by the kidneys. Urine often becomes dark. Result? _________________________________________ 6. ______________________________________ occurs when plasma fills the lungs 7. ______________________________________ occurs – failure of many organs leads to shock A combination of any of these pathologies leads to death in 8-10 months.

49. Sickle Cell Anemia Presence of falciparum malaria has resulted in the maintenance of another disease which affects black persons in Africa. Cause:

50. Sickle Cell Anemia Persons who are ___________________________ have rbc’s that are sickle shaped, and die of other factors by age 30. They are hh . H - normal gene h - sickle cell gene

51. Sickle Cell Anemia Persons who are ___________________________ have rbc’s that are sickle shaped, and die of other factors by age 30. However, if a person is ___________________________ for the sickle-cell anemia, rbc’s are normal shaped but are protected from invasion of merozoites of P. falciparum ; thus, the person is protected from falciparum malaria.

52. Sickle Cell Anemia cont. Selective pressure of malaria in Africa has led to the maintenance of an otherwise undesirable gene in the population. Problem occurs ___________________________ where malaria is no longer endemic – __________of African Americans are heterozygotes (Hh) and could transfer the trait to their offspring.

53. Diagnosis and Treatment of Malaria DIAGNOSIS - identify parasites within human erythrocytes in a s stained blood smear (this is what we are doing in lab)

59. Chloroquine resistant P. falciparum common Chloroquine resistant P. malariae in _______________________

64. Distribution of Malaria in the World Extent of malaria in the world before any eradication programs were started.

65. Distribution of Malaria in the World

66. Malaria in the U.S. About ______________cases of malaria are diagnosed in the U.S. each year. How were Americans infected?

68. Malaria in the U.S. By the 1950's malaria was eradicated from the U.S. due to: 1. 2.

69. Malaria Eradication Because malaria eradication was successful in the U.S., the World Health Organization began a worldwide eradication program in 1956. What did they have for eradication? 1. 2. It was thought that this was it for malaria.

71. Malaria eradication failed. Why? 1. Money was not available to combat mosquitoes or treat human cases. (Energy crisis of 1970's took alot of money away from malaria eradication) 2. Disease occurs in third-world countries where the disease is poorly understood by the masses. 3. Trained medical personnel and hospitals are few in number in these countries. 4. Resistance of P. falciparum to chloroquine, mefloquine, and Fansidar. 5. Resistance of Anopheles mosquitoes to ____________and other insecticides

72. Malaria Prevention 1. Avoid mosquito bites – use insecticides, repellents, netting Probably the cheapest and most effective way to reduce malaria is the use of insecticide-treated bed nets. A bed net costs $10 and can last up to 4 years “ Malaria No More” is a non-profit agency that provides bed nets to Africa.

77. Despite all these advances, malaria will likely be with us as long as there are humans on this earth.