JABALPUR

UNIT-5 (PROTOZOA OF VETERINARY IMPORTANCE)

Topic

Morphology, epidemiology, pathogenesis, clinical signs, diagnosis and

control measures of protozoan parasites belonging to the families: Theileriidae

Dr. Rupesh Verma

Assistant Professor, Deptt. of Veterinary Parasitology
College of Veterinary Science & Animal Husbandry (NDVSU), Jabalpur MP
Phylum Apicomplexa
Class Sporozoa
Order Piroplasmida
Family Babesidae
Genus Theileria
Species Vector Disease Host Distributions

Theileria annulata Hyalomma Bovine Tropical Theileriosis or Buffaloes & Cattle Mediterranean
anatolicum Mediterranean Coast Fever basin and pars of
anatolicum (MCF) Asia
Theileria parva R. appendiculatus East Coast Fever (ECF), Classic Buffaloes & Cattle Central, East and
disease, Bovine theileriosis Southern Africa
(January disease) (Turning
sickness)
Theileria mutants R. evertsi Benign bovine theileriosis, Buffaloes & Cattle Africa, Asia,
(Turning sickness) Australia Russia &
USA
Theileria lawrenci R. appendiculatus Corridor disease Buffaloes & Cattle East & central
Africa
Theileria lestoquardi Hyalomma Malignant ovine / caprine Sheep & Goat Northern and East
(formerly Theileria hirci) anatolicum theileriosis Africa, and middle
anatolicum (Small ruminants theileriosis) Asia

Theileria ovis R. bursa & Ovine theileriosis Sheep & Goat USSR & India
Haemophysalis spp.
Theileria equi Hyalomma spp., Equine biliary fever Horses, donkeys,
Rhipicephalus spp giraffes
T. bicornis R.evertsi evertsi Black, white and
Indian rhinoceros
T. buffelis Haemophysalis spp. Benign theileriosis Buffaloes

Theileria camelensis Hyalomma Camel Somalia Egypt

dromederii
T. orientalis Haemophysalis spp. Being theileriosis cattle cosmopolitan
1. Transovarial or transovarian transmission
 Transmission of parasites from parent to offspring
via the ovaries.
 E.g. one host ticks (Babesia infection only)

2. Transstadial transmission
 Transmission of the parasites from one stage to
next stage (through the molt to the next stage(s)
or stadium)
 E.g. three host ticks (Babesia & Theileria
infection)
1. Sexual multiplication (Definitive Host)- invertebrate animals (Ticks)

2. Asexual multiplication (Intermediated Host) Vertebrates animals

 Life cycle of Theileria
1. Schizogony
Ticks having sporozoites feed on vertebrate host for 2- 4 days

Sporozoites in salivary glands of ticks will mature and become infective

Sporozoites ingested into vertebrate host

Sporozoites enter into lymphocytes and develops into schizonts in the lymph node
(In case of T. parva)

In T. annulata infection, they invade macrophages or monocytes to form schizont rather

than lymphocytes

Causing lymphocytolysis which leads to immunosuppression, pulmonary edema and may

be anemia

Infected lymphocytes transformed into lymphoblasts which continue to divide having

schizonts

Eventually infected lymphoblasts are disseminated throughout the lymphoid system and non
lymphoid organs
There are two types of schizonts

 Macroschizont: Lymphocytes with large schizonts, commonly known as Koch's blue

bodies, appear a few days after onset of symptoms. One with large chromatin granules

gives (8-16 macromerozoites).

 Microschizont: Later, lymphocytes infected with microschizonts appear. One with small

chromatin granules gives (50-120 Micromerozoites) and they infect to RBCs (Sexually

differentiated)

 Infection of RBCs is important for transmission and infection of lymphocytes is important

for pathology. Damage mainly by schizonts

2. Merogony

Later some schizonts differentiate into merozoites

They are released from lymphoblasts and invade erythrocytes

In erythrocytes they are referred as Piroplasms

Merozoites develop into trophozoites which further asexually divide into merozoites

Merozoites are then released by rupture of the host red blood cells and invade healthy
erythrocytes

Sexual multiplication of the parasite starts by gametocytes appearing in the host red blood
cells
3. Gamogony

During blood uptake by ticks, gametocytes develop into gametes that mature in the tick
midgut lumen

Inside these, the zygote undergoes a meiotic division and results in the formation of kinetes
(Vermicules/ ookinetes), which are released to the haemolymph.
 The kinetes of Theileria species directly invade salivary glands (primary kinetes) but kinetes
of Babesia parasites are subjected to two series of asexual multiplication in various tick
tissues and subsequent secondary kinetes invade the tick salivary glands
4. Sporogony
Sporogony starts after kinete invasion of tick salivary glands (type III acinus), which form
the sporont, a polymorphous syncytium

The sporont later evolves into a multinucleated meshwork referred as a sporoblast, which is
dormant during tick ecdysis

Maturation of the parasite sporoblast starts after tick attachment to the host and results in
sporozoites being released into tick saliva
 Within host leukocytes the parasite induces leukocyte cellular division, which expands the

parasitized cell population.

 Infected cells disseminate throughout the lymphoid system via the lymphatic and blood

vessels.

 The infected leukocyte may block capillaries, causing tissue ischemia.

 This is followed later by necrosis of infected lymphoblasts induced by cytotoxic T-

lymphocytes. The severe lymphocytolysis often leads to immunosuppression.

 Later in infection some schizonts cause leukocyte lysis and release of merozoites.

 Merozoites then invade and parasitize erythrocytes, causing hemolytic anemia.

 The East Coast fever (T. parva infection) is characterized by a generalized

lymphadenopathy due to lymphocyte infection. Hyperplastic, hemorrhagic, edematous,

and necrotic lymph nodes have been observed in acute cases of the infection.

 In addition, interlobular emphysema and severe pulmonary edema have also been

reported. Lymphoid cellular infiltrations appear in the liver and kidney and hemorrhages

and ulceration may be seen throughout the gastrointestinal tract.

 „The tropical theileriosis‟ (T. annulata infection) is characterized by macrophage infection

that causes the release of cytokines (TNFα), anemia, and the presence of macroschizonts

in infected macrophage-type cells.

 Clinical symptoms
 Swelling of the draining lymph node, usually the parotid
 Fever 40 – 41o C, maintained until death or recovery
 Nasal discharge , Lacrimation
 Swelling of the eyelids and ears
 Anemia, Jaundice, Anorexia, Heart beat rapid, dyspnea, diarrhea
 Poor condition and severe lymphadenopathy in heifer

Enlargement of superficial lymph nodes

Lacrimation Rear case Corneal opacity

Nasal Discharge Diarrhoea

Turning sickness: an aberrant form of theileriosis in which
parasitized lymphocytes cause emboli and hemorrhagic infarcts in
central nervous tissue.

Occasional cases of brain involvement occur and are

characterized by circling, hence 'turning sickness' or cerebral
theileriosis due to the presence of schizont in the cerebral
capillaries

Theileria parva
Theileria mutans

Animal make CIRCLING MOVEMENT and ABDUCTION

OF HINDLIMB
 Post mortem lesion
 Lymphocytes proliferate heavily invading multiple organs causing
disease similar to a lymphoma (cancer of lymphocytes)

 Splenic enlargement.

 Severe pulmonary emphysema and edema along with hydrothorax and

hydro pericardium.

 Generalized lymphoid hyperplasia.

 Small lymphoid nodules (the so-called pseudo-infarcts) are present in

liver, kidney, and alimentary track.

 The carcass is emaciated and hemorrhages are evident in a variety of

tissues and organs. Death is in most cases due to infiltration of the
lung resulting in lung edema (the abnormal build up of fluid within
the lung)
 The Lymph node is enlarged and diffusely
pale, and contains numerous petechiae.

Pulmonary emphysema and edema

Multiple pale foci on the cortical

surface of the kidney are lymphoid
infiltrates.
Hydro pericardium Abdominal ulcers due to
transformed lymphocytes

Kidney, There are multiple

petechiae on the surface of the
cortex. The lymph node near the
hilus is markedly enlarged
PUNCHED OUT NECROTIC ULCER IN ABOMASUM
 Diagnosis

History
Presence of Ticks, Seasonal occurrence

Clinical Findings
Lymph node swelling, anaemia , icterus

Post-mortem findings
Punched necrotic ulcer in Abomasum

Blood smear exam

Presence of Piroplasm stage in Blood smear some time KBB( Common in T. parva)
T. parva schizonts in Lymphoblasts & T. annulata schizont in
macrophages/monocytes

Lymph node biopsy

lymph nodes, spleen and liver biopsy presence of KOCH BLUE BODIES
Theileria Piroplasmosis

Lymphoblasts containing
Theileria parasites
Xenodiagnosis
In Theileria annulata infection in salivary gland of tick use Methyl
Green Pyronin staining

Animal Inoculation
In Live animals, theileriosis can be diagnosed by finding schizonts in
Giemsa-stained thin smears from blood or lymph node biopsies. At
necropsy, schizonts may be found in impression smears from many
internal organs.

Cultivation
The intralymphocytic stages of Theileria parva, T. lawrencei and T.
annulata have been cultivated for several months in tissue cultures of
bovine lymphocytes associated with baby hamster kidney cells.

Medium RPMI-1640 supplemented with 20% foetal bovine serum

(standard growth medium) resulted in optimum growth of T.
annulata (Hisar) schizonts in vitro.
Serological test
Antibodies to T. parva and T. annulata can be detected with enzyme–
linked immunosorbent assays (ELISAs) or an indirect fluorescent
antibody test (IFA).

Tests used for T. parva and T. mutans are indirect ELISAs based on
parasite-specific antigens, PIM and p32, respectively

Molecular Test

Fluorescence resonance energy transfer (FRET)-based real-time

assays have also being developed for specific diagnosis of T. parva

A reverse line blot (RLB) assay based on hybridisation of PCR

products to specific oligonucleotide probes immobilised on a membrane
for simultaneous detection of different Theileria species has been
introduced.
Conservation of the18S V4 hyper variable region and ITS-1 & ITS-
2 Genes

Recombinant Theileria annulata sporozoites surface protein

(rTaSP/TaSP) antigen

Sporozoites surface antigen -1 (Spag-1)

 Merozoites surface antigen) (rTams-1/Tams-2)

PCR amplification of the p33/34 genes of the T. orientalis/buffeli

complex followed by restriction enzyme analysis can be used to
characterize the various types
 Treatment

 Tetracyclines(@5-10mg/kg B.W.)- used earlier

 Broad spectrum antibiotics like oxytetracycline(@10mg/kg

B.W.),
 Chlortetracycline (only against schizontal stages)

 Parvaquone 10 mg/kg two injection at 48 hrs interval (for both

schizontal and piroplasmal stage)

 Buparvaquone(butalex,bupaven,zubion ,50mg/ml)
@2.5mg/kgB.W.,im, two injection at 48 hrs interval (for both
schizontal and piroplasmal stage)Drug of choice

 Halofuginone lactate @1.2mg/kg b.w. ORALLY

 Control

Control of vector i.e. ticks mainly of Hyalomma spp. By

application of insecticides(like deltamethrin(butox,12.5mg/ml)2-
3ml/litre of water, Ivermectin(hitek,neomec,1%w/v)@0.2mg/kg, s/c)
and rotational grazing(breaks the transmission cycle between cattle
&tick).

Exotic & Crossbred cows should be kept in tick free shed.

Recovered Cattle are immune to homologous challenge

Avoid nutritional stress

Chlortetracycline@16mg/kg B.W..orally for 8 days, or
Rolitetracycline@4mg/kg B.W., im, for 3days in calves

Immunoprophylaxis-
“Infection and treatment method”-injection of cryopreserved susp. Of
sporozoites from ground up infected tick

Live vaccine efforts have been made to immune the animals by

transfer of infected blood

1. Rakshavac-T vaccine
IVRI, Bareilly, have evolved tissue culture live attenuated schizontal
stage (2*106 cells), Indian immunologicals, @3ml, s/c, primary
vaccination at 2 months age & revacc after 1 year, (1-3yrs protection).
For cross bred and exotic cattle

2. Anti Vector Vaccine

 Symptomatic treatment includes ANTIPYERETICS -
e.g.paracetamol@10mg/kgB.W. and
ANTIINFLAMMATORY DRUGS -e.g.meloxicam@0.2-
0.3mg/kgB.W, ANTIDIARREOALS-e.g.neblon powder@30-
50g ,b.i.d.,centrogyLM@4-6boli/day

 Supportive therapy also provided HEMATINICS -

e.g.ferritas,bolus@2boli/day &inj@1ml/50kg,
imferon@0.5-1g/week

 Liver protectants and restoratives may also be given,e.g.liv-

52vet@1-2bolus,bid
1. Heartwater because of pulmonary edema and hydrothorax.
Examination of brain smears and lymph node or spleen impression
smears can differentiate between the two diseases.
2. Trypanosomiasis because of edema, lymphadenopathy, and
anemia. Blood and lymph node smear examination will normally
differentiate between the two diseases.
3. Babesiosis and anaplasmosis because of anemia. These diseases
can easily be differentiated from theileriosis on examination of
blood smears.
4. Malignant catarrhal fever because of lymphadenopathy and
corneal opacity. Examination of blood and lymph node smears will
clearly differentiate between the two diseases.