4. Introduction
Life Cycle
Pathogenesis
Diagnosis
Control
Questions
Life cycle in tick similar to that of
Babesia. But no transovarial
transmission (Multi-host ticks).
Two different cell types are
infected in the mammalian blood
stream (initially leukocytes, later
on RBCs).
Infection of RBCs is important for
transmission and infection of
lymphocytes is important for
pathology.
6. Introduction
Life Cycle
Pathogenesis
Diagnosis
Control
Questions
Theileria hijacks and exploits two key features of the
lymphocyte’s cell biology:
Cell Division
Growth Control
Parasites do not egress from (and in the process destroy)
their host cells and infect new lymphocytes but
proliferate along with them.
A recently divided infected lymphocyte
The tight association of parasites with host cell
microtubules ensures that they are segregated by the
host cell mitotic spindle between the two daughter cells.
The arrow indicates the cleavage furrow
at which cytokinesis occurred. Blue
(DNA), red (host cell centrioles), green
(parasite surface membrane), HN (host
nucleus)
7. Introduction
Infiltration of
kidney by
Theileria
parva infected
lymphocytes
Life Cycle
Pathogenesis
Diagnosis
Control
Questions
Abdominal
ulcers due to
transformed
lymphocytes
• Lymphocytes proliferate heavily invading multiple organs causing
disease similar to a lymphoma (cancer of lymphocytes).
• Death is in most cases due to infiltration of the lung resulting in
lung edema (the abnormal build up of fluid within the lung)
8. Introduction
Life Cycle
Pathogenesis
Diagnosis
Control
Questions
Theileria infection seems to share many of the features seen in the
transformation of normal cells into cancer cells:
• Uncontrolled growth
• Loss of differentiation
• Immortalization (infected cells
taken into culture will grow
indefinitely)
• Growth in the absence of external
growth factors
• Enhanced ability to migrate and to
infiltrate organs
• When cells are cured from parasite
infection they die (by apoptosis -this suicide response is usually
suppressed in cancer cells)
9. Introduction
Life Cycle
Pathogenesis
Diagnosis
Anemia
Swelling of the
Superficial Lymph
Nodes
Anorexia
Questions
Generalized
Lymphadenopathy
High Fever
Control
Decreased milk
production
Diagnosis
Tachycardia (Rapid
Heartbeat)
Weakness/Loss of
Condition
Lacrimation &
Corneal Opacity
Nasal Discharge
Terminal dyspnea
Diarrhea
• Stained Blood Smears
• Serological
Examination
• Biopsy
• Gene Diagnosis
