Vaccine is a preparation that is used to stimulate the body's immune response against diseases. Vaccines are usually administered through needle injections, but some can be administered by mouth or sprayed into the nose.

1. PROTOZOAL AND
RICKETTSIA VACCINES
RITHIKA.R.S | II M. SC. BIOINFORMATICS
DEPARTMENT OF BIOINFORMATICS,
SRI KRISHNA ARTS AND SCIENCE COLLEGE, COIMBATORE.

2. PROTOZOA
Department of Bioinformatics, SKASC
 Protozoans are eukaryotic, unicellular, heterotrophic organisms
 Can be either parasites or free-living
 They exhibit an enormous range of morphologies and lack cell walls.
 4 major Groups:
• Mastigophora or Flagellated protozoans
• Sarcodina or Amoeboids
• Sporozoa or Sporozoans:
• Ciliophora or Ciliated protozoans:

3. Diseases caused by protozoans
Department of Bioinformatics, SKASC
Name of the Disease Causal organism
Malaria Plasmodium falciparum, P. vivax, P. malariae, P.
ovale
Amoebiasis or Amoebic dysentery Entamoeba histolytica
African Sleeping sickness or Trypanosomiasis Trypanosoma brucei gambiense, T. brucei
rhodesiense
Trichomoniasis Trichomoniasis vaginalis
Toxoplasmosis Toxoplasma gondii
Balantidiasis Balantidium coli
Giardiasis Giardia lamblia or duodenalis
Leishmaniasis or Kala-azar Leishmania donovani

4. Protozoal Vaccines
Target host Target parasite Vaccine Preventive mechanism
Human
Plasmodium
falciparum (pre-
erythrocytic)
RTS, S (6 October
2021, WHO
recommended
RTS,S as malaria
vaccine)
Inhibits sporozoite motility and invasion of
hepatocytes
Leishmania (L.)
infantum
LeishF3 (Phase III
trials)
Increases the secretion of IFN-γ, TNF-α, IL-2,
IL-5, and IL-10 in response to the vaccine
antigen
Dog
Leishmania (L.)
infantum chagasi
Leishmune® Prevents infection; blocks transmission;
increases CD4+, CD8+, and CD21+
lymphocyte rates
Leishmania (L.)
infantum
Canileish® Increases Th1 IgG and IgM responses,
leishmanicidal activity of macrophages, and
expression of iNOS and NO

5. Protozoal Vaccines
Target host Target parasite Vaccine Preventive mechanism
Dog
Leishmania (L.)
infantum chagasi
Leishtec® A2 is expressed in amastigotes and
involved in resistance
Leishmania (L.)
infantum
Letifend® Increases IgG2 and DTH response
Dogs and
cats
Giardia lamblia Giardiavax® Prevention and treatment of clinical
signs and reduction of cyst shedding
Human vaccination is not yet possible for any protozoa
infections other than Malaria.
Department of Bioinformatics, SKASC

6. ‘RTS, S’ Vaccine, Components and
Mechanism
 RTS, S/AS01 is a recombinant protein-based malaria vaccine.
 ‘R’ stands for the central repeat region of Plasmodium (P.) falciparum
circumsporozoite protein (CSP);
 ‘T’ for the T-cell epitopes of the CSP; and
 ‘S’ for hepatitis B surface antigen (HBsAg).
 Additional HBsAg to improve purification, hence the extra "S"
 RTS,S also contains the AS01 adjuvant system (to increase the immune system
response), and referred to as ‘RTS,S/AS01’.
Department of Bioinformatics, SKASC

7. ‘RTS, S’ Vaccine Mechanism
Department of Bioinformatics, SKASC
The RTS and S, these two protein
components assemble into soluble virus-
like particles similar to the outer shell of
a hepatitis B virus.
The T-cell epitope of CSP is O-
fucosylated in Plasmodium falciparum
and Plasmodium vivax, while the RTS,S
vaccine produced in yeast is not.

8. RICKETTSIA…
 The rickettsiae are a diverse collection of obligately
intracellular Gram-negative bacteria
 Found in ticks, lice, fleas, mites, chiggers, and mammals
 They include the genera Rickettsiae, Ehrlichia, Orientia,
Bartonella , and Coxiella
Department of Bioinformatics, SKASC
Red-stained Rickettsia rickettsii

9. Various strains and diseases…
Species Disease caused
Rickettsia Rocky Mountain spotted fever, rickettsialpox, other spotted
fevers, epidemic typhus, and murine typhus
Ehrlichia Ehrlichioses (resembles Rocky Mountain spotted fever)
Coxiella Q fever, which may present as an acute febrile illness with
pneumonia or as a chronic infection with endocarditis
Bartonella (Rochalimaea) quintana Trench fever
Orientia (Rickettsia) tsutsugamushi Scrub typhus
Department of Bioinformatics, SKASC

10. Vaccines for
Rickettsia

11. Conclusion
 Protozoa are single celled eukaryotic organisms and they are parasites which causes many deadly
diseases.
 Licensed vaccine exists only for Malaria that is RTS, S and for Leishmaniasis the vaccine is still
under Phase III trials.
 Currently, no vaccines are available to prevent RMSF in either people or dogs.
 Vaccine development against rickettsial infection is complicated due to the limited understanding.
 The use of mRNA and adenoviral vectors are promising ways of delivering antigens.
Department of Bioinformatics, SKASC

12. THANK YOU