Occurrence of Theileria parva infection in cattle on a farm in the Ladysmith district, KwaZulu-Natal, South Africa (original) (raw)
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Journal of the South African Veterinary Association, 2008
Theileria parva causes widespread morbidity and mortality in cattle in endemic regions. An outbreak of theileriosis occurred on a farm near Ladysmith in KwaZulu-Natal, South Africa, which is not a declared Corridor disease-infected area. A survey of Red Brangus cattle from all age groups and areas of the farm was performed. Transmission of the parasite from infected animals on the farm to susceptible animals by tick transmission and tick-stabilate injection, was attempted. The survey indicated high numbers of animals with antibody titres to T. parva but only 6 infected animals, based on real-time PCR and RLB analysis. The transmission experiments failed to transmit the parasite. The study shows the difficulty in elucidating a source of infection and determining the dynamics of new infections in a herd where multiple possible sources are present and treatment with tetracyclines has taken place.
Carrier state studies in Theileria parva infected cattle in Zimbabwe
1997
from T. parva macroschizont cells 4.3 Polymerase chain reaction conditions for p67 T parva primer 80 sequence 4.3.1 Optimisation ofPCR conditions using p67 primers 4.4 Polymerase chain reaction conditions forp104 T. parva primer sequence 4. 4.1 Sensitivity of PCR assay using p 1 04 primers 4.5 Detection ofPCR products. 4.5.1 Polyacrylamide gel electrophoresis 4.5.1 (a) Silver staining ofPolyacrylamide gels 4.5.2 Agarose gel electrophoresis of DNA 4.5.3 Preparation ofT parva Muguga probe 4.5.3.1 Blot Preparation 4.5.3.2 DNA labelling and hybridisation 4.6 RESULTS 4.6.1 Specificity ofp67 PCR assay 4.6.2 Optimisation results ofPCR conditions using p67 primers 4.6.3 PCR results forT parva Marikebuni infected calf (818) using p6 7 primers 4.6.4 PCR results forT parva Boleni infected calf (805) using p67 primers iii 94 94 95 96 Page No: 4.6.5 Specificity of assay using p 104 primers 4.6.6 Sensitivity ofPCR assay using p104 primers 97 4.6.7 Results of tests on carrier recovered animals using dot blot hybridisation 97 4.6.7.1 T. parva Boleni infected calves p104 PCR results 97 4.6.7.2 T. parva A very infected calves p104 PCR results 100 4.6.7.3 p104 PCR results ofT. parva Bally Vaughan infected calves 101 4.6.7.4 p104 PCR results of calves infected by application of Ayrshire and Chikeya ticks 4. 6. 7. 5 p 1 04 PCR results of calves infected by exposure to ticks at Hunyani Estates (1st exposure) 4.6. 7.6 p 104 PCR results of calves infected by exposure to ticks at Hunyani Estates (2nd exposure) 4.7 DISCUSSION CHAPTER FIVE Detection of Theileria parasites in infected I recovered cattle by tick application 5.1 XV reactions. PCR using p 1 04 primer sequences for rhoptry I microneme antigens of T. parva was the most sensitive indicator of carrier status. Clinical signs upon infection were not correlated with persistence of infection; carriage of parasite DNA occurred irrespective of initial severity. The IF A test was validated using sera from the carrier animals and naive animals pre-infection. The IFAT titre required to detect all infected animals was 1:160, at which the test had a specificity of only 64.63%. An IFAT cutoff titre of 1:320 resulted in a sensitivity and specificity of 90.49.% and 88.06% respectively. The current cutoff used in Zimbabwe (1 :640) resulted in 100% specificity, but sensitivity of only 64.63%. The PCR employed provided a highly sensitive method for determining T parva infection, was more sensitive than IF AT (cut-off 1 :640) and tick pick up. At least 71.7% of the samples tested post infection were positive by PCR compared to the 44% positives by IFAT at a cutoff of 1:640. Only 15% of the tick application experiments were positive compared to the 80.6% PCR positive tests and 38.9% IFAT positives when the tests were carried out synchronously. Each of the isolates resulted in a carrier state detectable by PCR and this lasted for at least 500 days, with Theileria transmission to ticks recorded up to 456 days post infection. This is longer than recorded in previous studies in Zimbabwe. These results suggest that carrier status is the normal state following infection. Indications are that T parva Boler:U is the most suitable immunising parasite stock; although T parva Avery and Bally Vaughan infections did not result in onward transmission to ticks, these parasites are of higher pathogenicity which would be disadvantageous in vaccination. xvi CHAPTER ONE Carrier state studies in Theileria parva infected cattle in Zimbabwe :left prescapular gta!1d :right prescapular gland :weak positive CHAPTER FIVE Detection of Theileria parasites in infected I recovered cattle by tick application 5.1
Ticks and Tick-borne Diseases, 2013
Corridor disease (Theileria parva infection in cattle associated with carrier buffaloes) had not been reported to cause serious outbreaks in South Africa prior to 1994. In recent years, there has been an increase in the introduction of T. parva-infected buffaloes onto private game parks in Northern KwaZulu-Natal (KZN). The objectives of this study were to investigate the number of T. parva outbreaks in cattle at the livestock/wildlife interface and to establish the possible T. parva carrier status in cattle which were diagnosed to have recovered from clinical disease. The occurrence of outbreaks was closely monitored from 2004 to 2009 covering a total of 15 localities. The observations included the number of cattle involved in the outbreaks, clinical signs, parasitological and post-mortem examinations, as well as serological and molecular tests specific for T. parva. Sentinel cattle were introduced to monitor tick transmission and some of these recovered from clinical T. parva infection in the field and confirmed to be positive by PCR, were challenged using lethal T. parva stabilates to ascertain their immune status. Thirty-one Corridor disease outbreaks were recorded during the study period. Of the 846 cattle tested for Corridor disease during the study period, 140 (16.5%) were found positive by the real time PCR and IFA tests. Eighty-two (9.7%) cattle were found positive by the IFA test only. The prevalence of T. parva infection was 26.2%. Adult R. appendiculatus fed as nymphs on 5 bovines which recovered from clinical T. parva infection in the field transmitted only T. taurotragi to susceptible bovines. However, 8 of the field-recovered cattle resisted lethal challenge using T. parva tick stabilate. Though the study could not demonstrate cattle-to-cattle transmission by ticks using 5 previously infected cattle in the field, it is suggested that Corridor disease should be considered a potential emerging disease, and more stringent control methods should be implemented.
Tropical Animal Health and Production, 2017
Ticks and tickborne diseases (TBDs) are serious constraints to cattle production in Tanzania and other tropical and subtropical countries. Among the TBDs, East Coast fever (ECF) is the most important as it causes significant economic losses to the cattle industry in Tanzania. However, control of ECF in Tanzania has continued to be a challenge due to inadequate epidemiological information. The main objective of this study was to determine the epidemiological situation of Theileria parva infections in cattle kept under pastoral and agro-pastoral farming systems in Mara, Singida, and Mbeya regions of Tanzania. Blood samples were collected from 648 cattle in the three regions. Genomic DNA was extracted and amplified in a polymerase chain reaction (PCR) using T. parva-specific primers targeting the 104-kD antigen (P104) gene. In addition, information was collected on the possible risk factors of T. parva infection (animal age, region, animal sex, tick burden, tick control method, and frequency of acaricide application). The prevalence of T. parva across the three regions was 14.2%. There was variation in prevalence among the three regions with Mara (21.8%) having a significantly higher (p = 0.001) prevalence than the other regions. Moreover, Mbeya exhibited relatively lower prevalence (7.4%) compared to the other regions. Factors found to be significantly associated with an animal being PCR positive for T. parva were region (p = 0.001) and tick burden (p = 0.003). Other factors were not found to be significant predictors of being PCR positive for T. parva. The present study showed high variation in tick burden and T. parva prevalence across the regions. Therefore, different strategic planning and cost-effective control measures for ticks and T. parva infection should be implemented region by region in order to reduce losses caused by ticks and ECF in the study area.
Livestock Research for Rural Development
A cross-sectional study of T. parva antibody and parasite prevalence were conducted on smallholder farms in Tanzania to compare the impact of two tick control regimes. A total of 182 cattle was sampled, whereby 104 were under constant exposure to ticks with minimal or sporadic tick control and 78 animals were kept in a regular weekly or biweekly tick control. Across the two sites, 179 cattle were positive for T. parva antibodies determined by a PIM ELISA corresponding to an overall seroprevalence of 98.4%. Using a nested p104 PCR, prevalence of T. parva parasites were shown to be 37.1% across the two sites. Cattle under the sporadic tick control had significantly higher antibody levels compared to those managed under regular tick control (p=0.0014). Highest T. parva antibody percent positivity was 62.1 for cattle under regular tick control, but this parameter was 87.3 in cattle under sporadic tick control. On the contrary, T. parva PCR results revealed a significantly higher parasit...
Tropical Animal Health and Production, 1981
Cattle living in a circumscribed area in Uganda, where both Theileria parva and T. mutans occurred naturally, were monitored for periods of up to 1 year by examination of blood and lymph node smears for parasites and the indirect fluorescent antibody test for antibodies to Theileria. Uninfected control cattle were added at intervals to ensure continuous challenge and to monitor the challenge. Although all 29 control animals became infected with T. parva, challenge was light at first as mortality from theileriasis only commenced in the 18 introduced after day 138 of the study; 14 of these died of the disease. Most of the 34 animals in the original group appeared to be susceptible to T. parva at the start of the study and 6 died of theileriosis. All animals were, or became, infected with T. mutans. Several animals exhibited patent T. parva infections on more than 1 occasion and 1 died from the second infection indicating the existence of immunologically different strains. Recovered animals appeared to acquire eventually a solid immunity to the local Theileria strains but 9 of the original animals and 7 of the controls died exhibiting massive tick and helminth burdens, sometimes aggravated by the effects of previous T. parva and/or T. mutans infections.
Preventive Veterinary Medicine, 2021
East Coast fever (ECF) in cattle is caused by the protozoan parasite Theileria parva, transmitted by Rhipicephalus appendiculatus ticks. In cattle ECF is often fatal, causing annual losses >$500 million across its range. The African buffalo (Syncerus caffer) is the natural host for T. parva but the transmission dynamics between wild hosts and livestock are poorly understood. This study aimed to determine the prevalence of T. parva in cattle, in a 30 km zone adjacent to the Serengeti National Park, Tanzania where livestock and buffalo co-exist, and to ascertain how livestock keepers controlled ECF and other vector-borne diseases of cattle. A randomised cross-sectional cattle survey and questionnaire of vector control practices were conducted. Blood samples were collected from 770 cattle from 48 herds and analysed by PCR to establish T. parva prevalence. Half body tick counts were recorded on every animal. Farmers were interviewed (n = 120; including the blood sampled herds) using a standardised questionnaire to obtain data on vector control practices. Local workshops were held to discuss findings and validate results. Overall prevalence of T. parva in cattle was 5.07% (CI: 3.70− 7.00%), with significantly higher prevalence in older animals. Although all farmers reported seeing ticks on their cattle, tick counts were very low with 78% cattle having none. Questionnaire analysis indicated significant acaricide use with 79% and 41% of farmers reporting spraying or dipping with cypermethrin-based insecticides, respectively. Some farmers reported very frequent spraying, as often as every four days. However, doses per animal were often insufficient. These data indicate high levels of acaricide use, which may be responsible for the low observed tick burdens and low ECF prevalence. This vector control is farmer-led and aimed at both tick-and tsetse-borne diseases of livestock. The levels of acaricide use raise concerns regarding sustainability; resistance development is a risk, particularly in ticks. Integrating vaccination as part of this community-based disease control may alleviate acaricide dependence, but increased understanding of the Theileria strains circulating in wildlife-livestock interface areas is required to establish the potential benefits of vaccination.