Babesiosis is caused by the protozoan Babesia that infects red blood cells, similar to malaria. It is transmitted through tick bites. The main Babesia species infecting humans are B. microti in the USA and B. divergens in Europe. Clinical manifestations include fever, chills, and hemolytic anemia. Diagnosis involves microscopic examination of blood smears to detect the pear-shaped Babesia trophozoites inside red blood cells. Treatment involves a combination of clindamycin and quinine. Prevention focuses on limiting outdoor activities in tick-infested areas and using tick repellents.

1. Babesiosis
Samah Hassan Soliman Yahia
Assistant professor of parasitology

2. Intended
learning
outcomes ILOs
Identify the main Babesia species infecting humans.
Compare mode of transmission of Babesiosis with that of
malaria disease
Demonstrate points of difference between Babesia and plasmodium life
cycle.
Discuss the clinical manifestation, parasitological diagnostic
techniques of Babesia.
Differentiate between Babesiosis and malaria; clinically and
laboratory.
Outline the treatment and preventive measures of
Babesiosis.
By the end of this lecture, you will be able to:

3. Historical background
The genus Babesia was named after the Romanian
bacteriologist Victor Babes, who in 1888
attributed “hemoglobinuric fever” of cattle and
sheep to inclusions he detected within
erythrocytes.

4. Geographical distribution

5. General facts
Intracellular RBCs parasite
(Apicomplexan parasites that infect red blood cells)
Tick- borne disease
(spread by certain ticks-mainly nymph)
Human infection
Babesia microti (USA)
Babesia divergens (Europe)
Medical importance
malaria-like disease????

6. Parasite
ecology
• Definitive host: Hard ticks
(sexual multiplication).
• Intermediate host: Mammals
(Man, cattle and rodents, asexual
multiplication occurs).
• Infective stage: Sporozoites
• Diagnostic stage: Trophozoites
inside RBCs

7. • landscape modifications affecting tick
populations.
• Increase in deer populations which
could disseminate infection.
• Different leisure activities in tick
infested woodland or agro-ecosystems.
• The movement of cattle by bovine
trade or repopulation processes may
disseminate new pathogens or new
pathogen strains.

8. Mode of transmission to human hosts
Tick bite Blood transfusion
Transovarian transmission between
tick generations
Rarely
Mainly

9. Tick
host
Human
host
zygote

10. Clinical picture
 Incubation period: 1 to 4 weeks.
 Most infections are asymptomatic.
 Manifestations of disease include fever, chills, sweating, myalgia, fatigue,
hepatosplenomegaly and hemolytic anemia.
 The disease is more severe in patients who are immunosuppressed, splenectomized
and/ or elderly (opportunistic infection).

11. Definitive hosts
Life cycle Exoerythrocytic stage
Human infectivity to insect
Human host preferences
Blood picture ????

12. Diagnosis
Indications of diagnosis
 History of live/travel to Babesia-endemic
areas
 Patients presents with febrile illness:
 Those who live in tick endemic areas
Within 6 month of blood transfusion

13. * Direct (specific) diagnosis
Microscopic examination of thick and thin blood film stained with Giemsa
(need multiple blood smears over several days)
Babesia
trophozoite
Distinguishing
features
Ring form is
most
common
Round, pear-
shaped or
ameboid
No pigment
No change in RBCs shape or size
Appearance of white vacuole
Multiple invasion
of RBCs (>12)
No schizont
No gametocyte
Occasional
presence of tetrads
Maltase cross
Parasitemia
1-20 % immunocompetent
85% immunocompromised

14. * Non-Direct (nonspecific) diagnosis
Non- direct
Animal Inoculation:
isolation of the organisms by
inoculation of patient blood into
hamsters.
Antibody detection
by ELISA
Molecular diagnosis
by PCR

15. Treatment:
Combination of clindamycin and quinine

16. Prevention
No vaccine for human use
No role for antibiotic prophylaxis
When being in endemic area:
* Limit outdoor activities
* Wear clothes that cover lower part of the
body
* Apply tick repellents to skin and clothing