bio 597 theileriosis
TRANSCRIPT
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By Julie Murchie and Victoria Paesani
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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. parvahas 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
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Threat mostly in eastern,central, & southern Africa
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Cattle *
Waterbuck
Indian Water Buffalo* African Buffalo
*develop symptomatic infections
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4) Lymphocyte lymphoblast (enlargedlymphocyte) and
3) Sporozoite enterslymphocyte (WBC) schizont
6) 10-15 days post-infection, schizont merozoite (invadeserythrocyte (RBC))
1) Sporozoites producedin tick salivary glands
2) Sporozoites transfer toungulate if tick is attachedfor 48-72 hrs
5) divides with schizont inside 2 infected daughter cells
7) In RBC,merozoitepiroplasm (infectticks)
8) RBCsingested bynymphs duringfeeding
Incubation Period
Experimentally Infected: 8-12 days
Naturally Infected: up to 3 weeks
9) Once in gut, undergoessexual reproduction motile stage, moves to
ticks salivary gland
* 5-8 days post-infection:found in lymph nodes* Schizonts increase 10-
fold every 3 days
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FirstSigns
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.
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Vaccination
Infect animal with the sporozoite form of theparasite while at the same time treating the cattlewith an antibiotic drug to lessen the severity ofthe infection
Pasture Management
Herd-Selection of Resistant Animals
Tick Control & Eradication
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Induction of Acquired Immunity in Pastoral
Zebu Cattle Against East Coast Fever After
Natural Infection by Early Diagnosis andEarly Treatment
Matovelo et al. 2003
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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.
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Two villages in the Morogoro Rural District
Two seasons (April and November)
Ear tagged 280 calves
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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.
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Indicator
Variable
Clinical
status
Rectal
Temperature
Lymph node
status
Respiratory
performance
Demeanor
Mild Above 39.5 C Swollen
parotidlymph-node
Normal Normal
Moderate Above 39.5 C Swollen
parotid and
Prescapular
node
Slight
labored
breathing
Nasal
discharges
Normal
Severe Above 39.5 C Swelling off
all superficial
lymph nodes
Respiratory
distress
Reluctant to
move/
recumbence
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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 forT. Parva parasites.
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100 animals were diagnosed with ECF
Most prominent clinical signs were fever andlymph node enlargements.
81% of animals were positive for ECF on atleast one screening method.
During follow-up, only 5 individuals were
diagnosed with ECF a second time.
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Diagnostic
Means
Cases
Tested
Missing
Clinical
Responses
Total Cases Mild Moderate Severe
Clinicalsigns of
ECF
100 0 100(100%) 4 66 30
Lymph
nodesmears
99 1 67(67.68%) 3 42 22
Blood
Smears
98 2 41(41.84%) 1 27 13
No test
detected
__ __ 19(19%) 1 13 5
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Majority of cattle that were treatedrecovered. (98% recovery rate)
Shows that early diagnosis and early
treatment is a reliable means to diagnosecattle with ECF on a basis of clinical signs in
endemic areas.
Reliable early signs of infection are fever and
swollen lymph nodes.
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Use of chemotherapy with the earlydetection 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.
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East Coast Fever is caused by Theileria parvaHosts
Intermediate= cattle
Definitive= ticks
Incubation time is anywhere from 8 days to 3weeks.
Very expensive
High morbidity & mortality rates
No harm to human health
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Matovelo, Gwakisa, Gwamaka, Chilongola, Silayo, Mtenga, Maselle, and Kambarage. "Induction of Acquired
Immunity in Pastoral Zebu Cattle Against East Coast Fever After Natural Infection by Early Diagnosis and
Early Treatment." The Journal of Applied Research In Veterinary Medicine. 2003. Web. 23 Mar. 2011.
.
Azeem Photos. 2010. A blue water is looking well with animal Waterbucks. . Accessed 22 March 2011.
Department for International Development Animal Health Programme, University of Edinburgh. 2005. R8042
Integrated control of East Coast fever in cattle of small-holder farmers. . Accessed 21 March 2011.
Food and Agriculture Organization of the United Nations. 1983. Eradication an alternative to tick and tick-
borne disease control. . Accessed 22 March
2011.
International Laboratory for Research on Animal Diseases. 1991. ILRAD 1990: Annual Report of the
International Laboratory for Research on Animal Diseases. Nairobi: International Laboratory for Research on
Animal Diseases.
Malcolm J. G., et al. 2005. Genome Sequence ofTheileria parva, a Bovine Pathogen That Transforms
Lymphocytes. Science 309:134-136.
Melhorn, H. Genus Ripicephalus Brown ear tick. Heinrich-Heine-Dusseldorf University. . Accessed 22 March 2011.
Morzaria, S.P. Identification ofTheileria species and characterization ofTheileria parva stocks. InternationalLaboratory for Research on Animal Diseases. . Accessed
23 March 2011.
Science and Development Network. 2005. Genetic codes of cattle-killing parasites cracked SciDev.Net.
. Accessed 22 March
2011.
Smith, M.C. Special Problems of Meat Goats (VET-595). Ambulatory and Production Medicine, New York State
College of Veterinary Medicine, Cornell University.
.Accessed 22 March 2011.
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