2. Phylum Apicomplexa
Caused by a tick-borne obligate intracellular parasite, Theileria parva, in sub-
Saharan Africa, infecting ungulates
Major constraint to livestock production & food security in many developing countries
Causes high morbidity & mortality, killing 1 million cattle every year
Prevents introduction of very productive but disease-susceptible breeds of cattle
Expensive to control
Places a huge economic burden on poor smallholder farmers
Costs nearly $170 million yearly
Some African counties use the cattle as forms of currency
T. parva has ability to induce cancer in host cell in a way that is reversible
Studies have provided clear links to cancer biology in humans
Studying this parasite has given researchers clues for the right direction
Vaccines have the power to eradicate the disease
Not hazardous to human health
Brown Ear Tick
6. 4) Lymphocyte lymphoblast (enlarged
lymphocyte) and…
3) Sporozoite enters
lymphocyte (WBC) schizont
6) 10-15 days post-
infection, schizont
merozoite (invades
erythrocyte (RBC))
1) Sporozoites produced
in tick salivary glands
2) Sporozoites transfer to
ungulate if tick is attached
for 48-72 hrs
5) …divides with schizont inside 2 infected daughter cells
7) In RBC,
merozoite
piroplasm (infect
ticks)
8) RBCs
ingested by
nymphs during
feeding
Incubation Period
Experimentally Infected: 8-12 days
Naturally Infected: up to 3 weeks
9) Once in gut, undergoes
sexual reproduction
motile stage, moves to
tick’s salivary gland
* 5-8 days post-infection:
found in lymph nodes
* Schizonts increase 10-
fold every 3 days
7. First Signs
appear 7-25 days after tick attaches
Parotid gland swells
Ear is preferred feeding site
Fever
Anorexia & decrease in overall condition
Later Signs
Lacrimation, corneal opacity
Nasal discharge, terminal dyspnea
Interlobular emphysema & sever pulmonary edema
Before death, temperature falls & dyspnea intensifies
Some develop neurologic disease “turning sickness”
Due to affected cells blocking circulation in capillaries within the CNS
Death (18-30 days after infestation by ticks)
The few survivors become lifelong immune carriers. Majority of these
cases, asymptomatic carriers can be recognized with little or no effect on
their productivity. Minority develop chronic disease problems that result in stunted
growth in calves and lack of productivity in adult cattle.
8. Vaccination
Infect animal with the sporozoite form of the
parasite while at the same time treating the cattle
with an antibiotic drug to lessen the severity of
the infection
Pasture Management
Herd-Selection of Resistant Animals
Tick Control & Eradication
9. Induction of Acquired Immunity in Pastoral
Zebu Cattle Against East Coast Fever After
Natural Infection by Early Diagnosis and
Early Treatment
Matovelo et al. 2003
10. 1. Examine efficiency of
chemotherapy of natural ECF
cases to look at protective
immunity against ECF in cattle.
2. Design a regimen farmers can use to help
minimize cattle loss due to ECF. This is done by
establishing early disease diagnosis and early
treatment.
11. Two villages in the Morogoro Rural District
Two seasons (April and November)
Ear tagged 280 calves
12. Farmers were trained to monitor the animals for
clinical symptoms of ECF.
Qualifying clinical symptoms: enlargement of
superficial lymph nodes, increase in
body temperature, dullness, and
respiratory distress.
Animals diagnosed with ECF
were treated with buparvaquone.
Severity of the disease at the time of treatment
was categorized based on the criteria set for ECF
clinical reactions with some modifications.
14. Treatment responses were categorized as
prompt/rapid, slow, or died.
Examined serum antibodies to T. parva, with
samples at the beginning and end of study,
using ELISA.
Studied blood and
lymph node smears for
T. Parva parasites.
15. 100 animals were diagnosed with ECF
Most prominent clinical signs were fever and
lymph node enlargements.
81% of animals were positive for ECF on at
least one screening method.
During follow-up, only 5 individuals were
diagnosed with ECF a second time.
17. Majority of cattle that were treated
recovered. (98% recovery rate)
Shows that early diagnosis and early
treatment is a reliable means to diagnose
cattle with ECF on a basis of clinical signs in
endemic areas.
Reliable early signs of infection are fever and
swollen lymph nodes.
18. Use of chemotherapy with the early
detection and early treatment approach
reduced mortality and helped cattle develop
immunity.
In terms of immunization, the early
detection and early treatment approach is a
reasonable alternative to the infection and
treatment.
19. East Coast Fever is caused by Theileria parva
Hosts
Intermediate= cattle
Definitive= ticks
Incubation time is anywhere from 8 days to 3
weeks.
Very expensive
High morbidity & mortality rates
No harm to human health
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Immunity in Pastoral Zebu Cattle Against East Coast Fever After Natural Infection by Early Diagnosis and
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