heileriases are a group of tickborne diseases caused by Theileria spp. A large number of Theileria spp are found in domestic and wild animals in tick-infested areas of the Old World. The most important species affecting cattle are T parva and T annulata, which cause widespread death in tropical and subtropical areas of the Old World. T lestoquardi, T luwenshuni, and T uilenbergi are important causes of mortality in sheep.

1. TROPICAL THEILERIOSIS
(MEDITERRANEAN COAST FEVER)
Submitted by,
Ranjini Manuel

2. HISTORY
• Theileria parasite was first reported by Arnold Theiler. T. annulata was first described
in 1904 in Transcaucasian cattle.
• A significant feature of the disease is hemolytic anemia
• Yaks are highly susceptible
• Humans are not affected

3. Etiology
• Theileriosis - protozoan disease caused by obligate intracellular parasites
• T. parva and T. annulata are the two most pathogenic species of Theileria affecting
cattle. T.orientalis – South India
• Theileria annulata – Tropical theileriosis /Mediterranean coast fever
• Theileria parva – East coast fever
• Vector – Hyalomma anatolicum ( trans-stadial transmission, 3 host tick)
• Species susceptible– cattle, goat, sheep, horses, ungulates
• Natural host – buffaloes

4. Epidemiology
• The diseases occur from Morocco and Portugal through Mediterranean basin
and Middle East to India and china.
• In endemic area, virtually all cattle are affected
• Case fatality approx. 10-20% confined mainly to calves. In case of exotic animal
which are recently introduced may have 20-90% mortality
• Single tick can cause fatal infection due to large no of sporozoites in their
salivary gland. Since there is elevated tick activity in monsoon and summer
disease becomes more prevalent in this period.

6. Risk and Immune Mechanism
• Recovered animal show solid immunity but they remain as carriers
• Carrier animals have decreased milk production.
• Economic importance- major constraint to many livestock improvement
programs. 1/6th of cattle population is under risk.

7. Transmission & Pathogenesis
• Theileria species are transmitted by tick vectors. Ticks must be attached for at least 48-
72 hours for transmission of parasites.
• Infective sporozoites in the saliva of tick are injected into the host These sporozoites
then enter into the lymphocytes of the host.
Hyalomma anatolicum

8. a) Lymphocyte stage: -schizonts (Koch’s blue body) invade monocytes/macrophages which expresses
major histocompatibility (MHC) classII antigens
Stimulate other uninfected lymphocytes to undergo lymphoblastic transformation
Schizonts infected cell multiply in draining lymph nodes and disseminate through out the body
b)Merozoite stage: - Schizonts  merozoites and leave the lymphocytes and enter into RBC 
Piroplasms These piroplasms are seen like a ring/comma/spherical/ovoid shape

9. c) Tick stage:- ticks suck the blood from infected host. Piroplasm  gut and gametogony takes place in
intestinal cells
After zygote formation  kinete (motile form )
Kinetes penetrate the thick salivary gland wall and form  sporozoites
Piroplasms induce hemolysis by lipid peroxidation of red cell membrane
*higher the level of parasitic burden, greater the haemolysis

11. Clinical findings
Fever
Inappetence
Tachycardia
IcterusSwollen LN

12. sub cutaneous nodules
Diarrhoea Weight loss
CLINICAL
FINDINGS

13. Clinical Pathology
• Blood smear and lymph node
biopsy
• For T.parva and T. annulata,
schizont stage is responsible for
pathology associated with infection
• For other species it is the
piroplasm stage in RBC induces
associated pathology.

14. • Significant feature –anemia and is associated bilirubinemia, hemoglobinuria
and bilirubinuria
• Anemia – as the result of RBC destruction containing piroplasms
• Other factors – auto immune haemolysis,
poor bone marrow response,
WBC and platelet count,
T lymphocytopenia

15. Serological Tests
• Indirect fluorescent antibody test (IFAT)
• ELISA – higher sensitivity and specificity than IFAT
• PCR- sensitive, specific and can detect carriers, can also be used to detect
infected ticks.
• Multiplex PCR method is used to detect single and co-infections with
T. annulata, B. bigemina, Anaplasma marginale in cattle

16. Necropsy Findings
• Small lymph nodules- liver, kidney,
alimentary tract
• Necrosis of lymph organs, lung,
kidney, liver and gastrointestinal
tract
Yellowish discoloration of tissues

17. Pulmonary edema
Ulceration of intestine
Enlarged lymph nodes

18. Differential Diagnosis
• Other theileriosis
• Babesiosis
• Anaplasmosis
• Trypanosomiasis
• Malignant catarrhal fever

19. Treatment
• Inj. Buparvaquone 2.5mg/kg I/M  2 doses 48hrs apart
• Halofuginone lactate 1.2mg/kg P.O
• Inj. OTC 20mg/kg I/M
• Supportive therapy

20. Control
• Indigenous cattle are mostly carriers they do not need intensive tick control and
treatment.
• Exotic stock require strategic tick control and vaccination
• Most economical – vaccinate calves & reserve Buparvaquone for treatment
• Vaccines Schizonts– live schizont grown in lymphoid cell culture &
attenuated by prolonged passage- good resistance for 3-5yrs

21. Raksha vac- T
• Raksha vac-T is the attenuated schizont vaccine
• Calves above 2 months and adults are given
• Contraindicated in advance pregnancy
• Reconstitution ; thawed vaccine concentrate 1ml
( 2 doses) in 5ml diluent
• Immunity develops in 6 weeks
• Good resistance for 3 years

22. ORIENTAL THEILERIOSIS
( Japanese Theileriosis)
• Etiology – T. orientalis
• Epidemiology – prevalent in Asia and Australia
• 4 genotypes – Ikeda, Chitose, Buffeli and type 5
• Ikeda – most pathogenic
• Transmitted by –Haemaphysalis ticks
• ( vertical transmission also reported)

23. Pathogenesis
• The life cycle of benign theileria forms are similar to that of other theileria species,
except that schizonts do not develop in leukocytes and hence do not induce
transformation and fatal lymphoproliferation
• After sporozoite inoculation, schizonts can be detected transiently in lymph nodes,
spleen, liver

24. • Schizont-infected cells are usually not found in the peripheral blood and they
do not play a major role in pathogenesis
• Piroplasms appear in the RBC after 10 days of infection, at this time there
may be fever and anemia. A transient reduction in the white blood cell count
also occurs (Kawazu et al. 1991).
• During the course of anemia, osmotic fragility of erythrocytes is reduced
and morphologically abnormal cells appear (Yagi et al. 1989; Yagi et al. 1991).

25. Enlargement of lymph node
CLINICAL SIGNS
• Moderate to severe anemia
• Moderate enlargement of lymph nodes
• In case of severe infection – high fever
• Swollen LN
• Hemoglobinuria
• Abortion
• decreased milk production
• Deaths
Pale mucous membrane

26. NECROPSY FINDINGS
Enlargement of spleen

27. Treatment
• Drugs like pamaquine/ primaquine, imidocarb, halofuginone lactate are also effective
against T. orientalis

28. Control
• Animals usually recover from the infection but often infection persists
• In conditions like transport stress, pregnancy, lactation, climatic change may cause
resuming of piroplasm proliferation.
• Areas of heavy tick infestation- immunization with piroplasm lysate- anemia upon
natural exposure to parasite.
• Acaricides- limit transmission- pour-on application of flumethrin