1. One day Workshop YUMS |Tissue and Blood Protozoan diseases
Malaria & Leishmaniasis
Mohammad Amin Ghatee
Ph.D in medical Parasitology

2. MALARIA THE KILLER DISEASE
500 million people suffer from malaria
Over one million of people die each year.
The majority of victims are children and pregnant women. (one African child every 30 seconds)
Sub-Saharan Africa bears 90 per cent of the burden.
Mal=bad
Area=aria= hava
Manateghe batlaghi
Paludism=malaria
Obligatory heteroxenous parasite

3. Plasmodium species which infect humans
Plasmodium falciparum (tertian)
Plasmodium vivax (tertian)
Plasmodium malariae (quartian)
Plasmodium ovale (tertian)
I am giving the old names for these malarias in parentheses to give some historical perspective in case you see these terms again. I will also explain how these old terms relate to the pathogenesis of these respective diseases and the associated fever patterns.
P.ovale is the last descriped plasmodium.
Phylum: Apicomplexa
Class: Sporozoa (هاگداران)
Order: Eucoccidida
Suborder: Haemosporina
Genera: plasmodium, Leucocytozoon, Haemoproteus, Hepatocystis)
Three subgenus:
P (plasmodium): schizont with more than 8 merozoites, with stippling, round gametocyte, high mammals as hosts, including 26 species ( 3 species infecting human).
P (Laverania): schizont with more than 8 merozoites, with stippling, bean-shaped gametocyte, high mamals as hosts, 2 species including one human pathogen that means P. (Laverania) falciparum.
P ( Vinckeia): schizont with less than 8 merozoites, no stippling, round-shaped gametocyte, primary (low level) mamals as hosts, 15 species including P.(vinckeia) bubalis
In overall, 100 species but only four species is pathogen for human
Strongly host specific but some monkeys were exerimentally infected by human plasmodiums.
P. Berghei and P. yoellii: rodents
P. gallinarum: birds?
P. cathemerium: birds?
P. simium: brazillian black monkey
P. knowlesi: east monkey
P.cynomolgy: baboon
P. shortti: Indian and cylanian monkey
P. Schwetzi: African chimpanzea
P. inui: east monkey
P. brasilianum: new world monkey
P. eylesi: long hand monkey (in Mali)

4. Geographical distribution and incidence of malaria
Figure 23.10

5. Plasmodium species
Plasmodium falciparum: Tropics. Accounts for 50% of all malaria cases. Most pathogenic.
Plasmodium vivax: Tropics, subtropics, and some temperate regions.. About 43% of all malaria cases. Some Africans are refractory to infection because the lack the red cell receptor that the parasite use to enter.
Plasmodium malariae: Tropics. About 7% of all malaria cases.
Plasmodium ovale: West Africa. Rare.
Benign tertian malaria = by Plasmodium vivax
Summer-fall malaria, malignant tertian malaria = Plasmodium falciparum
Quartiain malaria=P. malarie

6. HOSTS
DEFINITIVE HOST: Anopheline female Mosquito (sexual reproduction)
INTERMEDIATE HOST: Humans (asexual and sexual phases)
آنوفل ماده
انتقال بیماری احتملا از میمون به انسان در جنوب شرق اسیا و سپس گسترش به افریقا و اروپا و سپس از قرن 16 به آمریکا.

7. Malaria Life Cycle
پس از ورود گامتوسیت ها به معده پشه در اثر کاهش دما (دمای بدن پشه) به گامت تبدیل می شوند
میکروگامتوسیت با انجام میوزیس کاهش کروموزوموزومی می دهند و منجر به تولید 6-8 میکروگامت می شوند. ماکروگامتوسیت نمیدانم چگونه ولی ظاهرا میوز نمی کنند ولی n کروموزوم از طریق یک قطب انگل دفع می شوند کروموزوم دیگر به قطب دیگر به جدار داخلی انگل می چسبد و برامدگی ایجاد می کند. میکروگامتوسیت علاوه بر میوز ایجاد تاژک (exflagellation ) می کند. در زمان لقاح تاژک را از دست می دهد.
20 دقیقه پس از لقاح اووکینت کرمی شکل ایجاد می شود. 24 ساعت درون معده پشه است سپس دیاره معده را سوراخ و مابین دیواره خارجی و داخلی گات قرار می گیرد و ایجاد اووسیست می کند
Ookinet is an active zygote
Oocyst is 50 µm and ookunet is 20 µm.
Ookinet under sporogony converts to oocyst containing many sporozoites.
Oocyst open into haemocel (hofreh omomi badan va na mede va govaresh)
Sporozoirs go into salivary glands
Two salivary gland, each in one side of pharynx. Each salivary gland has three lobes
Sporozoites are haploid with prepheral fibrils that may play role in movement. It has mitochondria but no pigment.
Female anophele fed blood f host each 48h (gonotrophic cycle or oovolaton period) at early or late night
Sporogony (fly cycle) last 7 days for P. vivax, 14d for P. falciparum and d for P. malarie
sporozoite injection in each biting

8. Types of Infections Recrudescence Relapse
exacerbation of persistent undetectable parasitemia, due to survival of erythrocytic forms, no exo-erythrocytic cycle (P.f., P.m.)
Blood origin
Can be occurred along the life time
Relapse
reactivation of hypnozoites forms of parasite in liver, separate from previous infection with same species (P.v. and P.o.)
Tissue (liver) origin
Up to 3-5 years after primary infection
Hypnozoite: Schizozoite (slowly growing merozoite in liver), سلول خفته , no pigmentation in tissue schizont due to lack of hemoglobin.

9. Erythrocytic phase stages of parasite in RBC
Young trophozoites or ring form
Tropohozoite
forms merozoites
Schizogeny to forms merozoites releasing merozoites into blood stream.
Merozoites invade other RBCs and schizongeny is repeated
Parasite density increases until host’s immune response slows it down
Merozoites may develop into gametocytes (gametogony), the sexual forms of the parasite
Blue-body: parallel to erythrocytic schizogony (segmentation), some round and egg-shaped chromatin granules with blue color. Blue-body may have role in sexall features (stimulate the gametocyte production)
Gametocytogenesis starts following 3-4 erythrocytic schizogony. First, immature sexual feature (gamont) is produced that converts to microgametocyt or macrogametocyte in 6 days.
Macrogametocyte (female) number is more than microgametocyte to balance the numbers in anopheles

10. Development in the mosquito
Upon ingestion with a blood meal, both the micro and macrogametocyte rapidly mature
Macrogamete is released from ruptured rbc
Microgametocyte rapidly undergoes multiple nuclear divisions to form 8 gametes
Exflagellation

11. Development in the mosquito: the ookinete
A mature ookinete. A number of organelles are shown. The nucleus can be seen at the lower end of the organism. There are abundant ribosomes in the area above the nucleus and endoplasmic reditulum can also be seen. The zygote is surrounded by a three-layered pellicle. The apical complex at the upper end includes numerous rhoptries and micronemes (dark spots). Image from Sinden RE. "Malaria", Topics in Inernational Health,(1998) The WellcomeTrust, CABI Publishing, CAB International
Number of engulfed gametocytes by fly is important in the ability of anophele to infect human. This is 1 gametocyte against 1000 WBC for P. vivax, 2 gametocytes for P. malarie and 5 gametocytes for P. falciparum.
Plasmodium fed by pinocytosis and probably by an organel alike the micropore.
Glucose phophorylation for enery and globin chain to acquire amino acids.
G6PD reduces the glutation. Reduced glutation is needed for hexose monophosphate chant. Plasmodium uses the products of this chant like ribose-phosphate.
Host resistance to Plasmodium falciparum : G6PD deficiency, scickle cell anemia (abnormal Hb, it converts to column-shaped Hb when O2 is deficient.

12. Development in the mosquito
Encysted ookinete transforms into oocycst
10-14 days of development
reductional nuclear division, haploid again
multiplication to form 1000’s of sporozoites

13. THE OOCYST
Plasmodium transmitting Anopheles:
In Iran 10 species are vector
The most important: An. stephenci
The most prevalent: An. Superpictus
Southeast, south and central regions: An. dethali and An. Culicifacies
The most dangrous anophel: An. Fluviatilis vector of P. falciparum in sistan & Balochestan, Hormozgan and South Kerman
An. sacharovi in Ardabil and Azerbayjan
An. Maculipenis in Mazandaran and Gillan
SEM which shows two oocysts on the outer wall of the midgut of a mosquito. These contain developing P. gallinacium sporozoites.
Image from Guggehheim R."Malaria", Topics in Inernational Health,(1998) The WellcomeTrust, CABI Publishing, CAB International)
Anopheles gambiae, the deadliest malaria vector (top), and blue-colored Plasmodium oocysts, appearing from the mosquito’s gut. (MOSQUITO ENGINEERING:Building a Disease-Fighting Mosquito. Martin Enserink/Science : (in News Focus)

14. Merozoites attach to specific receptors (like some blood groups) by their conoids.
Hb F, thalasemy and duffy-: resistand to P. vivax
Applique (Accole): parasite attachment to the RBC, state or cresent-like parasite in periphery of RBC (probably inside RBC?)
After accole formation, a vacuele is formed and push parsite nucleus to the one side of RBC. Now it is ring form.
Vaivax name is derivate of Vigorous vocabulary with meaning of strong due to amoebic activity and form of throphozoite in RBC
Stippling occur in trophozoite form (like schufner )
36h for P.vivax and falciparum and 50h for P. malariehRing, growing trophozoite, old trophozoite

15. Schizogenic periodicity and fever patterns
Schizogenic periodicity is length of asexual erythrocytic phase
48 hours in P.f., P.v., and P.o. (tertian)
72 hours in P.m. (quartian)
Initially may not see characteristic fever pattern if schizogony not synchronous.
With synchrony, periods of fever or febrile paroxsyms assume a more definite 3 (tertian)- or 4 (quartian)- day pattern.
Initially continoius ( fever high in all day (24h) and variation lower than 1.5 F) or remittent ( fever high in all day (24h) and variation higher than 2 F). This adjust cycle of parasites with increasing the speed of convertion of immaature paraites to mature. Then so the fever periodicity synchronised.
Prepatent period: the time from entrance parasite to body till parasite appear in blood
Incubation period: the time from entrance parasite to body till manifestation of symptoms.

16. Clinical presentation
Early symptoms
Headache
Malaise
Fatigue
Nausea
Muscular pains
Slight diarrhea
Slight fever
Photophobia
Anorexia
Could mistake for influenza or gastrointestinal infection
Malaria 4-1 has longest common period ad malaria caused by P. falciparum has shortest.

17. Paroxysm of malaria
In cold stage (thrilling for min), the skin became pale like cyanosis
Rupture of sRBCs and release of merozoites couses decrease in RBCs and so blood circulation from skin diverted to the viscera to compensate. So patient feel coldness and thrill.
In fever stage (2-6h), fard hazyan migoyad, va dard shadid pishani, posht va dast opa shaye ast
An acute splenimegally may be observed
Schizont rupures, and release of pyogenic endotoxin from schizonts result in production of TNF , IL1 and IL6 from macrophages that affect on the methabolism of archidonic acid that results in production of prostaglandins. Prostaglsndins affect on the hypothalamus (center of temperature adjustment), that finally cause the fever

18. Malarial Paroxysm Periodicity
Days 1 and 3 for P.v., P.o., (and P.f.) - tertian
Usually persistent fever or daily paroxyms for P.f.
Days 1 and 4 for P.m. - quartian

19. Malaria Paroxysm
Malaria tertiana: 48h between fevers (P. vivax and ovale)
Malaria quartana: 72h between fevers (P. malariae)
Malaria tropica: irregular high fever (P. falciparum)

20. Normochrom normocytic anemia
In black water fever ( vast hemolysis of RBCs) results in hypochrom, microcytic anemia
Anemia: 1-periodic schizont and RBC lysis 2-auto-immune mediated haemolysis or through complement mechanism 3-increasing phagocytosis clean and infected RBCs by Spleen 4-cyto adherance and blockage of blood in capillaries that results in hypoxia, tissue damage and distrbance in electrolyte balance between cells and plasma and following entrance of plasma into interstitial space that results in decrease in blood plasma and false (not real) anemia. 5- DIC 6- thrombocytopenia and following bleeding result in anemia 7-black water fever
Malaria results in:
1- tropical splenomegaly syndrom (due to hyperproduction of Igm due to disturbance in T-supperssor that can not control B cells)
2-Cerebral malaria: most sever malaria feature, headache, drowsiness, comma, hemiparesis (bihesi yektarafeh) brain ataxia, hipotonia (zafe shadide azolani)
Rapid prescribtion of Quinin and qiunidin and blood exchange is essential
3-Reinal failure:
Acute renal congestion by P. falciparum: glomeronephritis, oligiria, anuria, edema
Chronic renal congestion by P. malarie due to immune complex more in children
4-Pneumonic malaria: pulmonary oedema,
1- alveolar capillary damage
2-secondry odema due to increase in blood plasma volume due to injection of liquids in an oliguric or anuric (renal congested) patient
5-aligid malaria: sever hypotention due to dsterbance in (ghodef foghe koliavi) and following feeling coldness in skin and sever hypothermic state and shock. It may be also due to septesemia by gram negative bacteria, pulmonary oedema, rupture of large spleen,
6-Black water fever: antibody mediated immune respone against knob results in vast heamolysis of RBCs (fever, kidny pain, jundice)
Also may be due to treatment with quinine
7-Dysantryic malaria: bleeding from upper GI due to capillary damages. Abdominal pain, nausia, vommiting, bleeding in GI
8- hyperparasitemia: cause cerebral malaria and death. Blood excheng can save patient life
9-hypoglycemia: tretment with quinine and quinidine resukt in hyperinsulinemia and following hypoglycemia that cause abortion or fetus problems in third semester.
In children hypoglycemia is not due to drug and hyperinsulenimeia but for disability of liver cells in glyconeogenesis

21. Malaria the disease 3 Severe manifestations Cerebral malaria
Severe anemia
Renal failure
Irritability, loss of reflexes, neurological symptoms similar to menigitis, coma
20% fatality
Progressive severe drop
of hematocrit, poor oxygen
Supply for organs and
tissues
Dwindling urine, high urea
Level in serum

22. Knobs and cytoadherence
Cytoadhrence and rosetting correlates with the presence of “knobs” (left column) on the surface of the infected RBC
The right column shows a RBC infected with a knob-less strain which does not cause cerebral malaria
Knobs are made up of parasite derived proteins
knobs
knob-less

23. Cerebral Malaria Possible metabolic effects, cytokines (eg, TNF-)
Pathophysiology
cytoadherence 
cerebral ischemia
hypoxia,
metabolic effects, cytokines (eg, TNF-)
coma
death

24. Severe anaemia - pathogenesis
Erythrocyte destruction during schizogony (destruction of both parasitized and nonparasitized erythrocytes)
Erythrophagocytosis in spleen
Immune mediated response
Black water fever
Spleen
Bone marrow suppression

25. Other severe complications
Pulmonary oedema
Renal insufficiency (nephrotic syndrome)
P. malariae
Haemolysis
Thrombocytopaenia, DIC
Superinfections (secondry infection)
Septicaemia

26. Immunity and Resistance in malaria
Protective immunity to malaria is primarily a premunition.
In highly endemic areas, infants are protected by maternal antibodies, and young children are at greatest risk after weaning.

27. Genetically resistance factors
Sickle cell anemia, favism, and thalassemia
can cause resistance to infection by P. f
-Duffy blood groups and P. v

28. Modes of transmission 1. Natural or biological transmission
2. Accidental transmission:
blood transfusion
sharing of needles by IV drug users
3. Maternal transmission

29. Malaria Diagnosis Clinical Diagnosis:
Symptoms: fever, chills, headache, malaise, etc.
History of being in endemic area
Splenomegaly and anemia as disease progresses

30. Malaria Diagnosis
Laboratory diagnosis:
Microscopic demonstration of parasite in blood smear (distinguish species)
thick film: more sensitive
thin film: species identification easier
Fluorescent microscopy
antigen detection ‘dipstick’
Serology
Polymerase Chain Reaction
Most important form of parasite for diagnosis of falciparum from others is gametocyte.
The best time for slide preparation is after paroxysm beccause parasites enter the new RBCs again.

31. 4.
Carry the drop of blood to the first slide and hold at 45degree angle. 1.
Touch 3 drops of blood to a clean slide. 2.
Spread the drops to make a 1 cm circle. 5.
Pull the drop of blood across the first slide in one motion. 3.
Touch a fresh drop of blood to the edge of another slide. 6.
Wait for both to dry before fixing and staining.

32. Malaria Blood Smear Remains the gold standard for diagnosis
Giemsa stain
distinguishes between species and life cycle stages
parasitemia is quantifiable
Requirements: equipment, training, reagents, supervision
Simple, inexpensive yet labor-intensive
Accuracy depends on laboratorian skill

33. Interpreting Thick and Thin Films
THICK FILM
lysed RBCs
larger volume
0.25 μl blood/100 fields
blood elements more concentrated
good screening test
positive or negative
parasite density
more difficult to diagnose species
THIN FILM
fixed RBCs, single layer
smaller volume
0.005 μl blood/100 fields
good species differentiation
requires more time to read
low density infections can be missed

34. Malaria Parasite Erythrocytic Stages
Ring form
Trophozoite
Schizont
Gametocytes

35. Plasmodium falciparum
Infected erythrocytes: normal size, maurers cleft, discrimination of P. falciparum from other species is a important, because P. falciparum in blood of non-immune case is a medical emergency. M I
Gametocytes: mature (M)and
immature (I) forms
Rings: double chromatin dots, multiple infections in same red cell
Schizonts: merozoites
(rarely seen in peripheral blood)
Trophozoites: compact
Double infection, triple infection,
Also double chromatin
Murrers dot: khormaii rang or dark red
thousands per cubic milimetter.
Falci-parum: means producer of scickle-shaped bodies (gametocytes)
Macrogametocyte: taxon-shaped, larger, thinner, more condensed chromatin
Microgametocyte: kidney-shaped, banana-shaped, shorter, wider, finer chromattin
In thick smear, young tropjozoite is comma or swallow shaped.
schizont is not seen in prepheral blood due to sticky property of RBC with schizont:1- knob( vesicles content of glycoprotein and glycolipid obtained from parasite metabolism) in RBC surface 2- change of structure of RBC surface protein 3- change in electrical charge 4- Prasite enzymes coverd the RBC surface

36. Plasmodium vivax
Infected erythrocytes: enlarged up to 2X; deformed; (Schüffner’s dots))
Rings
Trophozoites: ameboid; deforms the erythrocyte
Schizonts: merozoites
Gametocytes: round-oval
In thick smear, P. vovax trophozoites may be a thin cytoplasm near nucleus or thin cytoplasm in both sides of nucleus that are named “Comma” and “Swallow”, respectively.
Gametocytes of P. malarie, vivax and ovale are similar (round form) but P. malarie is smaller and darker without schfner dots. So other asexual forms must be evaluated for identification.
Male and female gametocytes in all species can be differentiated regarding fine and pale chromatin network of microgametocyte and dense chromatun of macrogametocyte.
P. Vivax invade young and so large and pale RBCs.
Ddouble-infection can be seen for P. vivax (like falciparum)
Schuffner dot is orange.
Parasitemia thousands per cubic millimeter of blood
P. Vivax previously was named as Haemamobea vivax.
Schuffner dots are being from growing (ameboid) trophozoite till latest form meaning gametocyte.

37. “malariae - like parasite in vivax - like erythrocyte”
Plasmodium ovale
Infected erythrocytes: moderately enlarged (11/4 X); fimbriated; oval; (Schüffner’s dots)
“malariae - like parasite in vivax - like erythrocyte”
Trophozoites: compact
Rings
Gametocytes: round-oval
Schizonts: 6-12 merozoites;(usually 8)
dark pigment
Only in West Africa, alternative, substitution for vivax in Wset Africa
James dot or Schuffner dot: dark red
Oval-shaped parasite,
Like vivax

38. Plasmodium malariae
Infected erythrocytes: size normal to decreased (3/4X), Zeimanns dots
Trophozoite:
typical
band form
Trophozoite:
compact
Schizont:
6-12 merozoites (usually 8);
coarse, dark pigment ; (“rosettes”)
Gametocyte:
round; coarse,
dark pigment
Old RBC that are smaller
RBC is with more color due to increase of pH.
20000 parasites per cubic mililitter
Ziemman dot” not seen with romanofsky stains, but yellow with florcent staining
Young trophozoite: band form or egg form
Rosset form mature schizont: 6-12 merozoites in around RBC and pigments in center of RBC.

39. Malaria Serology – antibody detection
Antibodies to asexual parasites appear some days after invasion of RBCs and may persist for months
Positive test indicates past infection
Not useful for treatment decisions
Investigating congenital malaria, esp. if mom’s smear is negative

40. Malaria Antigen Detection
Immunologic assays to detect specific antigens
Commercial kits now available as immunochromatographic rapid diagnostic tests (RDTs), used with blood
P. falciparum histidine-rich protein 2 (PfHRP-2)
parasite LDH (pLDH)
Monoclonal and polyclonal antibodies used in antigen (Ag) capture test
Species- and pan-specific Ab
Cross reactivity with rheumatoid factor reportedly corrected
Cannot detect mixed infections

41. Detection of Plasmodium antigens
A: HRP-2 (histidine-rich protein 2) (ICT)
B: pLDH (parasite lactate dehydrogenase)(Flow)
C: HRP-2 (histidine-rich protein 2) (PATH)

42. Polymerase Chain Reaction (PCR))
Molecular technique to identify parasite genetic material
Uses whole blood collected in anticoagulated tube (200 µl) or directly onto filter paper (5 µl)
Definitive species-specific diagnosis now possible

43. Immunity and Resistance in malaria
Much of the disease results from inflammatory and immune responses of the host
Release of proinflammatory cytokines, such as TNF and IFNγ, cause serious metabolic changes.

44. Immunity to malaria There is no sterile immunity to malaria
Patients produce strong antibody responses to PfEMP1 which is exposed to the immune system on the surface of the infected RBC.
Why is the immunity to malaria relatively weak?
PfEMP1 is encoded by a large multigene family (VAR genes) and parasites switch to new variants (antigenic variation again)
The parasite genome encodes 60 VAR genes, only one is expressed at a time (allelic exclusion)
This phenomenon depends on the VAR promoter

45. Immunity to malaria
Successful vaccination in humans has been achieved with large doses of irradiated sporozoites, however that is not practical
None has yielded a satisfactory and safe human vaccine yet
Currently, control depends on drug therapy

46. Treatment
Chloroquine
Primaquine
Quinine
Artemisinins

47. Selected Anti-Malarials
Blood schizonticides:
1-Rapid acting:
Chloroquine, Amodiaquine, Quinine, Quinidine, Mefloquine, Atovaquone, Artemisinin
2- Slow acting: Antifolates(Fansidar, proguanil) , Clindamycin, Tetracyclines, Proguanil
Tissue schizonticides: Primaquine , Proguanil
Gametocidal: Primaquine
Anti – relapsing: Primaquine

48. Chinchona the source of quinine
Peruvian Indians appear to have been the first to know about the medicinal effects of quinine.
They chewed Chinchona bark while working in the mines as forced laborers for the Spanish

49. Malaria Drug Therapy in Iran

50. Plasmodium falciparum & Plasmodium malariae infections
First day: Chloroquine 600 mg (4 tab), 6 h later: 300 mg
Second day: Chloroquine 300 mg
Third day: Chloroquine 300 mg & Primaquine 45 mg (3 tab)

51. Vaccine Radiated sporozoite Sporozoite recombinant proteins
Spf66: synthethic polypeptides of merozoites
RTS,S: recombinant HBV surface protein and parasite proteins

52. Plasmodium falciparum (CQ-resistant) infections
First day: Quinine 600 mg (3 tab) q8h & Fansidar 3 tab
Second day: Quinine 600 mg (3 tab) q8h
Third day: Quinine 600 mg (3 tab) q8h & Primaquine 45 mg

53. Plasmodium vivax infections
First day: Chloroquine 600 mg (4 tab), 6 h later: 300 mg
Second day: Chloroquine 300 mg
Third day: Chloroquine 300 mg & Primaquine 45 mg Weekly × 8 wks or 15 mg daily × 14 d

54. Severe anaemia P. falciparum – often, not always, high parasitaemia
Often prolonged duration
Hb < 5 g/dl (3 mmol/l)
Lactic acidosis – ’respiratory distress’
Haemolysis
Hyperbilirubinaemia
Haemoglobinuria (Black water fever syndrom)

55. P.v P.f P.m P.o

56. PARASITE FORMS Merozoite: invades erythrocytes
Sporozoite invades mosquito salivary glands and liver cells
Ookinete invades mosquito gut epithelial cells
Mosquito forms: gametocytes, Oocyst, ookinete, sporozoite
Blood forms: merozoites, rings, trophozoite, schizonts, gametocytes

57. The sporozoite
10-15 m long
Two sporozoite surface proteins contain hepatocyte adhesive domains (CSP circumsporozoite protein and TRAP thrombospondin related anonymous protein)
Both proteins bind to glycosoaminoglycans on the surface of hepatocytes

58. 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

59. Plasmodium blood forms: the ring stage
1st hours spent as ring stage, or young trophozoite
little to no Hb degradation
only form seen in blood films of P. falciparum

60. THE SCHIZONT
Schizogony: form of asexual reproduction in which multiple mitoses take place, followed by cytokinesis resulting in multiple daughter cells
multiple mitoses produce several nuclei
once nuclei & organelles replicated cytokinesis occurs
rupture of RBC membrane releases merozoites

61. Gamogony Formation of gametocytes
27, 28: Mature macrogametocytes (female); 29, 30: Mature microgametocytes (male).
Formation of gametocytes
trigger for this is unknown, in in vitro culture it is stress related.
9-10 day development for P. falciparum
36 hours development for P. vivax
in P. falciparum have characteristic banana shape

62. Malaria Paroxysm
paroxysms associated with synchrony of merozoite release
48 or 72 hr cycles
release of antigens, etc
 TNF-
temperature is normal and patient feels well between paroxysms
falciparum may not exhibit classic paroxysms
continuous fever (remittent)
paroxysms become less severe and irregular as infection progresses

63. Clinical Features
manifestations and severity depend on species and host status
acquired immunity
general health
nutritional state
genetics

64. Common features of P.vivax infections
Paroxysm duration 8-12 hours
Relapses
60% untreated or inadequately treated will relapse
Time from primary infection to relapse varies by strain
Treat blood stages as well as give terminal prophylaxis for hypnozoites

65. Common features of P. malariae infections
Clinical picture similar to P.v.
Incubation period long – days
Anemia less pronounced than P.v.
Gross splenomegaly but risk of rupture less common than in P.v.
No relapse – no hepatic phase or persisting hepatic cycle
Parasitemia rarely > 1%, all asexual stages can be present
Can cause nephrotic syndrome, prognosis is poor
The danger of transmission of this parasite through blood transfusion is evident.

66. 15% of cerebral malaria patients die

67. The main causes of the anemia are:
destruction of both parasitized and nonparasitized erythrocytes
inability of the body to recycle the iron bound in hemozoin
inadequate erythropoietic response of the bone marrow

70. Species Differentiation on Thin Films

71. Drugs Used to Treat Malaria
1- Tissue schizonticides
2- Blood schizonticides (drugs used to clinical cure)
3- Gametocides
- Drugs used to radical cure

72. Chloroquine 4-amino quinoline acts on asexual intraerythrocytic forms
useful for treatment or prophylaxis
safe for children and in pregnancy
side effects: GI, headache, blurred vision, pruritis
limited efficacy against P. falciparum
resistant strains of P. vivax emerging

73. Primaquine 8-aminoquinoline
acts on gametocytes, hypnozoites; weak against asexual blood stage parasites
primarily used as post-exposure prophylaxis and radical cure for P. vivax and P. ovale
contraindicated in G6PD deficiency and pregnancy
decreased activity against some P. vivax

74. Primaquine (PQ) use in P. vivax and P. ovale infections
Use to achieve radical cure and prevent relapses
Check glucose-6-phosphate dehydrogenase (G6PD) level first
PQ can cause hemolysis in G6PD-deficient patients
If mildly deficient, consider weekly PQ dosing instead of daily
Contraindicated in pregnancy
Pregnant women and newborns use prophylactic CQ weekly until delivery or until end of breast-feeding
Then use primaquine

75. Quinine first isolated from cinchona bark in 1820
dextroisomer: QUINIDINE
acts against asexual erythrocytic stages
used for treatment of all 4 species
safe in pregnancy and for children
side effects: nausea, blurred vision, tinnitus
diminished activity against some P. falciparum from SE Asia

76. Other Medications--Artemisinins
novel class of antimalarial drugs
derived from Chinese herb: qinghaosu
act on earlier parasite developmental stages than CQ or Quinine
rapid parasite clearance
no resistance to date, but high rates of recrudescence if used alone
effective in combination with MQ
neurological lesions in animal studies

77. Chloroquine the wonder drug
Chloroquine an artificial quinine analog developed by German and American chemists during WWII was a very potent drug that was cheap to make, stable and had no serious side effects
Chloroquine was a major part of the 60/70s malaria eradication campaign
None of the drugs developed since come close to chloroquine

78. Chloroquine accumulates in the food vacuole
The food vacuole is the home of hemoglobin digestion
Heme is toxic to the parasite (inducing of ROS production) and has to be polymerized into malaria pigment
Chloroquine is thought to interfere with this detoxification of heme

79. Resistance to chloroquine
1965
1960
1978
1989

81. Features of P.falciparum cases
Common features of P. falciparum infections
Fever constant or remittent
Hypotension, jaundice, tender hepatosplenomegaly
Can progress to severe malaria rapidly in non-immune patients
Cerebral malaria can occur with P.f.

82. Cerebral malaria
Cerebral malaria is characterized by multiple hemorrhages
Excessive serum and tissue levels of TNFa and INFg are associated with severe malaria
Some researchers believe this inflammation is the main cause for pathology

83. The life cycle of Plasmodium
Figure 23.11