Theileriosis East Coast Fever By Julie Murchie and Victoria Paesani East Coast Fever Phylum Apicomplexa Caused by a tickborne obligate intracellular parasite Theileria parva in sub Saharan ID: 768655
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TheileriosisEast Coast Fever By Julie Murchie and Victoria Paesani
East Coast Fever Phylum Apicomplexa Caused by a tick-borne obligate intracellular parasite, Theileria parva, in sub- Saharan Africa, infecting ungulatesMajor constraint to livestock production & food security in many developing countriesCauses high morbidity & mortality, killing 1 million cattle every yearPrevents introduction of very productive but disease-susceptible breeds of cattleExpensive to controlPlaces a huge economic burden on poor smallholder farmersCosts nearly $170 million yearlySome African counties use the cattle as forms of currencyT. parva has ability to induce cancer in host cell in a way that is reversibleStudies have provided clear links to cancer biology in humansStudying this parasite has given researchers clues for the right directionVaccines have the power to eradicate the diseaseNot hazardous to human health Brown Ear Tick
Geographic Range Threat mostly in eastern, central, & southern Africa
T. parva Primary Hosts Cattle * Waterbuck Indian Water Buffalo*African Buffalo*develop symptomatic infections
T. parva Lifecycle
4) Lymphocyte lymphoblast (enlarged lymphocyte) and… 3) Sporozoite enters lymphocyte (WBC) schizont6) 10-15 days post-infection, schizont merozoite (invades erythrocyte (RBC))1) Sporozoites produced in tick salivary glands2) Sporozoites transfer to ungulate if tick is attached for 48-72 hrs5) …divides with schizont inside 2 infected daughter cells7) In RBC, merozoite piroplasm (infect ticks)8) RBCs ingested by nymphs during feedingIncubation PeriodExperimentally Infected: 8-12 daysNaturally 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
Clinical Signs First Signsappear 7-25 days after tick attachesParotid gland swellsEar is preferred feeding siteFeverAnorexia & decrease in overall conditionLater SignsLacrimation, corneal opacityNasal discharge, terminal dyspneaInterlobular emphysema & sever pulmonary edema Before death, temperature falls & dyspnea intensifiesSome develop neurologic disease “turning sickness”Due to affected cells blocking circulation in capillaries within the CNSDeath (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 ontheir productivity. Minority develop chronic disease problems that result in stunted growth in calves and lack of productivity in adult cattle.
Treatment, Prevention, & ControlVaccination 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 AnimalsTick Control & Eradication
Case Study 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
Objectives 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.
Methods And Materials Two villages in the Morogoro Rural District Two seasons (April and November) Ear tagged 280 calves
Methods And Materials 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 ECFwere 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.
Categories of Clinical Status of ECF Cases Before TreatmentIndicator Variable Clinical statusRectal TemperatureLymph node status Respiratory performanceDemeanor Mild Above 39.5 ºCSwollen parotidlymph-nodeNormal Normal ModerateAbove 39.5 ºCSwollen parotid and Prescapular nodeSlight labored breathing Nasal discharges Normal SevereAbove 39.5 ºCSwelling off all superficial lymph nodes Respiratory distress Reluctant to move/ recumbence
Methods And Materials 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.
Results 100 animals were diagnosed with ECFMost 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.
Diagnostic Means Cases Tested Missing Clinical Responses Total Cases Mild Moderate Severe Clinical signs of ECF100 0 100(100%)46630 Lymph node smears 99167(67.68%)34222Blood Smears 98241(41.84%)12713No test detected ____19(19%)1135
DiscussionMajority 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.
Discussion cont. 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.
ConclusionEast Coast Fever is caused by Theileria parva Hosts Intermediate= cattle Definitive= ticksIncubation time is anywhere from 8 days to 3 weeks. Very expensive High morbidity & mortality ratesNo harm to human health
Sources 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. <http://www.jarvm.com/articles/Vol1Iss2/Matovelo.htm>.Azeem Photos. 2010. A blue water is looking well with animal Waterbucks. <http://azeem-photos.blogspot.com/2010/09/blue-water-is-looking-well-with-animal.html>. 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. <http://www.dfid-ahp.org.uk/index.php?section=4&subsection=48>. Accessed 21 March 2011.Food and Agriculture Organization of the United Nations. 1983. Eradication – an alternative to tick and tick-borne disease control. <http://www.fao.org/docrep/004/x6538e/X6538E00.htm#TOC>. 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 of Theileria parva, a Bovine Pathogen That Transforms Lymphocytes. Science 309:134-136.Melhorn, H. Genus Ripicephalus Brown ear tick. Heinrich-Heine-Dusseldorf University. <http://www.butox-info.com/ectoparasites/ripicephalus.asp>. Accessed 22 March 2011.Morzaria, S.P. Identification of Theileria species and characterization of Theileria parva stocks. International Laboratory for Research on Animal Diseases. <www.fao.org/Wairdocs/ILRI/x5549E/x5549e0t.htm>. Accessed 23 March 2011.Science and Development Network. 2005. Genetic codes of cattle-killing parasites cracked – SciDev.Net. <http://www.scidev.net/en/news/genetic-codes-of-cattlekilling-parasites-cracked.html>. 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. <http://www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2002&Category=&PID=5736&O=Generic>. Accessed 22 March 2011.
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