This is for Student

1. (Malaria parasite and Babesia)
By,
Bajarangi lal Chaudhary
Ph.D. Scholar

2. Chapter Outline
• Classification
• Malaria Parasite
• Babesia

3. CLASSIFICATION

4. The causative Agent of malaria
• P. vivax causes benign tertian malaria.
• P. falciparum causes malignant tertian
malaria.
• P. malariae causes benign quartan malaria.
• P. ovale causes ovale tertian malaria
• P. knowlesi causes quotidian malaria.

5. Life Cycle
• Host:Female Anopheles definitive and Man
intermediate host.
• Human Cycle:
a) Pre-erythrocytic Schizogony
b) Erythrocytic schizogony
c) Gametogony

6. Mosquito Cycle
• Exflagellation:
• Zygote:
• Ookinete:
• Oocyst:
• Sporozoites:
• Extrinsic incubation period:

7. Life cycle

8. Pathogenesis and Clinical Feature
• Benign malaria:It is characterized by a triad of
febrile paroxysm, anemia and splenomegaly.
• Febrile paroxysm:
(1) cold stage: 15 minutes to 1 hour.
The patient feels lassitude, headache, nausea,
intense cold, chill and rigor
(2) hot stage: 39–41°C
(3) sweating stage: Fever comes down with
profuse sweating

9. Anemia
• Parasite induced RBC destruction—Lysis of RBC
due to release of merozoites.
• Splenic removal of both infected RBC and
uninfected RBC coated with immune complexes.
• Bone marrow suppression leading to decrease
RBC production.
• Increased fragility of RBCs.
• Autoimmune lysis of coated RBCs.

10. Splenomaegaly
• Splenomegaly is due to
massive proliferation
of macrophages that
engulf parasitized and
nonparasitized coated
RBCs.

11. Falciparum malaria
(malignant Tertian malaria)
• Sequestration of the parasites: This leads to blockade of
vessels, congestion and hypoxia of internal organs.
• Mediated by:
• Cytoadherence :
• P. falciparum erythrocyte membrane protein-1 (PfEMP-1)
• Rosetting:
• Deformability
• Other virulence factors like:(HRP-II) and Glycosyl
phosphatidyl inositol (GPI)

14. Complications Falciparum malaria
• Cerebral malaria:
• Pernicious malaria:
• Black water fever:
• Algid malaria:
• Septicemic malaria:
• Pulmonary edema and adult respiratory distress
syndrome:
• Hypoglycemia:
• Renal failure:
• Bleeding/disseminated intravascular coagulation
• Severe jaundice:
• Severe normochromic, normocytic anemia:
• Acidosis:

15. Cerebral malaria

18. Chronic Complications of Malaria
• Tropical splenomegaly syndrome (hyperactive
malarial splenomegaly)
• Quartan malarial nephropathy
• Promotes Burkitt’s lymphoma

19. Malaria in Special Situations
• Transfusion malaria
• Malaria in pregnancy
• Malaria in children

20. Transfusion malaria
• The infective form is trophozoite
• There is no pre erythrocytic
stage of development and no
relapse
• The incubation period is often
short
• Radical chemotherapy with
primaquine is unnecessary as
there is no relapse

21. Malaria in pregnancy
• Malaria during
pregnancy increases the
risk of fetal distress and
can result in premature
labor low birth weight
and still birth

22. Malaria in children
• complications are relatively
common among children
like convulsions, coma,
hypoglycemia, metabolic
acidosis and severe anemia
whereas other complications
like deep jaundice, acute
renal failure, and acute
pulmonary edema are
unusual in children.

23. Plasmodium knowlesi
• It is a malaria parasite of monkey but can also
rarely affect humans.
• Anopheles leucosphyrus is the main vector
• The first human case was documented in 1965

24. Clinical features
• P. knowlesi produces an acute illness and
relatively high parasitemia.
• Paroxysms of fever occur daily (quotidian
malaria) because of short RBC cycle (24
hours)

25. Lab diagnosis
• The late trophozoites (with band forms),
schizonts (8–10 merozoites arranged in a rosette)
and round gametocytes of P. knowlesi, are
morphologically similar to that of P. malariae.
• No commercially available rapid diagnostic tests
(RDTs).
• (PCR) assays are available using the primers
Pmk8 and Pmkr9.

26. Immunity Against Malaria
• Innate Immunity:
• Age of red blood cells:
• Nature of hemoglobin:
• Hereditary ovalocytosis:
• Red blood cells with glucose-6-phosphate
dehydrogenase (G6PD) deficiency
• Duffy negative red blood cells
• HLA-Bw53
• Nutritional status

28. Acquired immunity
• Humoral immunity:
• Circulating antibodies (IgA, IgM and IgG)
against asexual forms give protection by
inhibiting the red cell invasion and sequestration,
whereas antibodies against sexual forms help in
reducing the transmission of malaria
• Cellular immunity:
• Cytokines released from T cells stimulate the
macrophages and also the B cells to produce
antibodies. stimulate

30. Epidemiology of Malaria
• Transmitted in 108 countries containing 3
billion people.
• P. vivax is the predominant species.
• Children are more prone to infection and
complications.

31. Malaria Situation
• P. falciparum is the most common
• Odisha was affected the most (24%) where 92%
of cases were due to P. falciparum infection.
• The largest focus of P. malariae in India is
reported to be in Tumkur and Hassan districts of
Karnataka.

32. Laboratory Diagnosis
• Microscopic tests: Peripheral blood smear—Gold
standard Thick smear—more sensitive
• Thin smear—speciation can be done
• Fluorescence microscopy (Kawamoto’s technique)
• Quantitative buff y coat examination
• Non-microscopic tests:
• Antigen detection tests (RDTs) or ICTs—detects
parasitic LDH, HRP-II, aldolase
• Antibody detection—ELISA
• Culture—RPMI 640 medium
• Molecular diagnosis—PCR using PBRK1 primer

33. Thin
and thick blood smear
• microscopic tests:
• Peripheral blood
smear—Gold standard
• Thick smear—more
sensitive
• Thin smear—speciation
can be done

34. Thin blood smear showing ring form of
Plasmodium malariae (band form)
Thin blood smear showing ring
form of Plasmodium ovale

35. Quantification of malaria parasites by
thick smear

36. P. Falciparum , thin Blood smear
(A) multiple ring form and accole form; (B) double dot (head phone
shaped) ring form; (C) gametocyte
A B C

37. Thin blood smear showing different forms of
Plasmodium vivax (A) ring form; (B) gametocyte;
(C) schizont
A B C

38. Fluorescence microscopy
• Kawamoto technique
• Blood smears are prepared on a
slide and are stained with
acridine-orange and examined
under a fluorescence
microscope.
• Nuclear DNA is stained green.

39. Quantitative Buff y Coat Examination
• It consists of three basic steps:-
1. concentration of blood by centrifugation
2. staining with acridine orange stain
3. examination under ultravoilet (UV) light source
• Interpretation:
• Normal RBCs don’t take up the stain (as they are
a nucleated). However, parasitized RBCs appear
as brilliant green dots. WBCs also take up the
stain

40. Quantitative Buff y Coat Examination
• (A) QBC capillary tube
(B) magnifi ed view of
QBC capillary tube after
centrifugation
A B

41. Antigen Detection by Rapid Diagnostic Tests
1. Parasite lactate dehydrogenase
(pLDH):produced by trophozoites and
gametocytes of all Plasmodium species.
2. Parasite aldolase: Produced by all Plasmodium
species
3. Plasmodium falciparum specifi c histidine rich
protein-2 (Pf-HRP-II):young (but not mature)
gametocytes of P. falciparum
• Sensitivity: 90% sensitive at >100 parasites/μL.

42. Quantitative Buff y Coat Examination
• (C) crescent shaped
gametocyte of
Plasmodium
falciparum
• (D) ring forms of
Plasmodium
falciparum seen as
fluorescent dots
C D

43. (A) Schematic diagram of rapid diagnostic test kit showing negative,
non falciparum, pure or mixed infection with Plasmodium falciparum and invalid
result of malaria;
A

44. Antibody Detection
• Detection of antibody in serum indicates past
malaria infection and is useful for:
a. Epidemiological survey in malaria
b. Screening of blood bank to identify the
infected donors.

45. Culture
• RPMI 1640 medium(Roswell Park Memorial
Institute and 1640 denotes the number of
passages) in a continuous flow system mixed
with a thin layer of RBC and an overlay
medium consists of human serum maintained
with 7% CO2 and 1–5% O2.
• The other media used are Delbecco’s modified
Eagle medium (MEM), RPMI 1630, and
Medium 199.

46. Molecular Diagnosis
• DNA probe: Highly sensitive if the parasite
count is low less than 10/μL.
• (PBRK1 primer)
• Speciation can be done
• Drug resistance genes can be detected
• Useful tool for epidemiological study.

47. Nonspecific Tests
• Normochromic and normocytic hemolytic anemia
• Leucopenia:
• Raised erythrocyte sedimentation rate (ESR)
• Raised serum C-reactive protein
• Prolonged prothrombin and partial thromboplastin time
in severe infection
• Decreased antithrombin III levels in mild infection
• Metabolic acidosis.
• Hypoglycemia
• Hypergammaglobulinemia

48. Treatment

49. Antimalarial Drug Resistance
• Falciparum malaria:
• Chloroquine resistant, Sulfadoxine-
pyrimethamine resistance, Mefl oquine
resistance
• Vivax malaria:
• Only sporadic cases of resistance to
chloroquine and/or primaquine in some areas
have been reported

50. Mechanism of drug resistance
• Chloroquine resistance in Plasmodium falciparum
• Occurs due to mutations in the genes encoding the
transporter proteins such as PfCRT (P. falciparum
chloroquine transporter) and PfMDR1 (P. falciparum
multidrug resistance gene 1).
• These proteins help in chloroquine influx into the
parasitic food vacuoles. Such mutation results in
impaired transport of chloroquine.
• More so, mutation in PfMDR1 gene leads to resistance
to other antimalarials like amodiaquine, mefloquine and
halofantrine.
• Resistance to antifolates such as sulfadoxine: point
mutation in DHFR (dihydrofolate reductase) gene.

51. Who Guideline for Assessing Degree of
Resistance
• In vivo method (2002) degree of resistance is
divided into four categories.
1. Early treatment failure (ETF):
2. Late clinical failure (LCF):
3. Late parasitological failure (LPF):
4. Adequate clinical and parasitological response
(ACR):

52. Prophylaxis Against Malaria
• Chemoprophylaxis:
• Weekly regimen: Chloroquine 300 mg or proguanil
400 mg, or mefloquine 250 mg.
• Daily regimen: Doxycycline 100 mg
• Vector Control Strategies:
• Residual spraying:-dichlorodiphenyl trichloroethane
(DDT), malathion and fenitrothion is highly effective
against adult mosquito
• Space application
• Individual protection:
• Larvicide: Use of mineral oil or Paris green
• Source reduction
• Biological larvicide:

53. Vaccination for malaria
• The vaccine candidates are poor inducer of cell
mediated immune response
• Antigenic variation in malarial antigens such
as PfEMP
• Different immune mechanisms occur in
different stages of malaria life cycle.

54. BABESIA
• It rarely affects humans causing opportunistic
infection.
• Babesia species are grouped into:
• Small Babesia species (1–2.5 μm):
B. microti, B. gibsoni and B. Rodhaini
• Large Babesia species (2.5-5 μm):
B. divergens and B. bovis.

56. Pathogenesis and Clinical Features
• Incubation period varies from 1 to 6 weeks.
• Mild Babesia microti illness: malaise, fatigue,
and weakness and fever.
• Severe Babesia microti illness:
• Infections by Babesia divergens, Babesia bovis
and Babesia duncani:

57. Epidemiology
• Babesiosis is highly endemic in the North
Eastern United States like Nantucket Island
and also in South Eastern Massachusetts
• It is an emerging infectious disease in other
countries.
• Sporadic cases are reported in Europe and
other places
• In India, Babesiosis is not reported yet

58. Laboratory Diagnosis
• Peripheral blood microscopy:-Detects maltese
cross form (ring form in tetrad)
• Serology antibody: IgM titers of 1:64 or more
and IgG titers of 1:1024 or more signify active or
recent infection
• Molecular method:18S rRNA gene (PCR)
• Animal inoculation

59. Giemsa stain blood smear showing maltese cross form

60. Treatment
• Oral atovaquone plus azithromycin for 7–10
days.

61. References
• Essentials Medical Parasitology by Apurba
Sankar Sastry.