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1.
A A Latif T Hove G K Kanhai S Masaka 《The Onderstepoort journal of veterinary research》2001,68(3):197-201
Eight cattle immunized with cattle-derived Theileria parva Boleni stabilate together with six susceptible controls were released in Dombawera Game Park on the Highveld of Zimbabwe. This coincided with Rhipicephalus appendiculatus nymphal activity. The cattle grazed together with African buffaloes (Syncerus caffer) and were not treated against tick infestation. The nymphal tick infestation was high, and seven of the eight immunized cattle and three of the controls had severe and fatal reactions. Subsequently, two stocks of Theileria parva to be tested for their immunizing abilities were prepared-one from adult ticks which were fed as nymphs on one of the sick control animals (Dom 268) and the other from adult ticks collected from pastures grazed by buffaloes (Bv-1). Two groups of cattle were immunized with either the Dom 268-derived strain (eight animals) or the Bv-1-derived strain (four animals). These together with three non-immunized controls, were released in Bally Vaughaun Game Park in the Highveld, where buffaloes are present, during the season of nymphal tick activity. A third group of five cattle, immunized with stabilate Bv-1, and three non-immunized controls were released at the same site during the season of adult tick activity. The nymphal and adult tick infestations of the cattle were large and more than 2000 nymphs and 1000 adult ticks were counted per animal. Cattle were treated with a pyrethroid pour-on preparation to control the tick infestation and screw-worm strike. The immunized cattle in the three groups survived the theileriosis challenge for a period of 18 months, but the non-immunized control cattle suffered a severe and fatal theileriosis 19-23 days after being placed on the pasture. 相似文献
2.
A A Latif T Hove G K Kanhai S Masaka 《The Onderstepoort journal of veterinary research》2001,68(3):203-208
The Theileria parva carrier-state in cattle on commercial farms on Zimbabwe was investigated using parasitological and serological methods. The proportion of cattle showing Theileria piroplasms on two farms, which had recent histories of disease outbreaks, were 64% (n = 106, total of heifers and weaned calves examined) and 71.5% (n = 60) while the proportion of T. parva antibodies for the same animals were 59% and 98.5%, respectively. On four farms where no cases of the disease occurred for over 10 years, the average proportion of animals showing piroplasms and antibodies were 55.4% (range 32-82, n = 223) and 73% (range 47-91, n = 223), respectively. However, on another three farms which had no history of theileriosis outbreaks these proportions were very low, being 11.4% (0-24, n = 157) for piroplasms and 12.2% (5-23, n = 157) for antibodies. The mean infection rate in unfed Rhipicephalus appendiculatus adults collected from farms with a high prevalence of cattle which were carriers of Theileria piroplasms during the tick activity season was 29% (range 12-60%) with 9.3 (range 2-18.7) mean infected acini per infected tick. The infectivity of different tick batches to susceptible cattle produced a wide spectrum of theileriosis reactions. Laboratory controlled experiments were carried out to study the persistence of T. parva (Boleni) piroplasms in cattle immunized with this strain as well as its infectivity for ticks and its subsequent transmissibility to cattle. Examination of the salivary glands of 15 batches of ticks collected from six immunized cattle on three different occasions over 18 months showed that none were infected with Theileria parasites. However, the infectivity of other ticks in the same batches to susceptible animals was demonstrated 6, 10 and 18 months after cattle had been immunized with Boleni stabilate. 相似文献
3.
A S Young J J Mutugi D P Kariuki D Lampard A C Maritim P N Ngumi A Linyonyi B L Leitch S G Ndungu A C Lesan 《Veterinary parasitology》1992,42(3-4):225-240
One hundred and one cross European-Boran cattle (50 cows and 51 calves), on a farm in Nakuru District, Kenya, were immunised against theileriosis using Theileria parva lawrencei and Theileria parva parva stocks from another district of Kenya. The stabilates used were T.p.lawrencei (Mara III) used at 10(-1.7) dilution and T.p.parva (Kilae) used at 10(-1.0) dilution. The stabilates were combined and inoculated simultaneously with a short-acting formulation of oxytetracycline hydrochloride given intramuscularly at 10 mg kg-1 body weight and was repeated on Day 4 after inoculation of the stabilate. Most of the theileriosis challenge on the farm was thought to be derived directly from the African buffalo (Syncerus caffer). Nine percent of the cattle had significant indirect fluorescent antibody (IFA) titres before the immunisation and 99% after immunisation. The immunised cattle were exposed to tick-borne disease challenge on the farm by withdrawal of acaricide cover. The immunised cattle were divided into five groups plus two susceptible control cows and two calves for each group. Cattle in four of the groups had acaricidal ear tags, each group having a different type, applied to both ears and the fifth group remained untagged. The animals remained without conventional acaricide application for 134 days. Ten out of 20 (50%) non-immunised control cattle became T.p.lawrencei reactors which only one out of 97 (1%) of the immunised cattle reacted. A frequent complication noted was mild infections due to unidentified Theileria sp. which required expert differentiation from T.parva infections. An additional group of ten steers whose tick load was removed by hand at weekly intervals was introduced 79 days after exposure; these had no tick control and four became T.p.lawrencei reactors. Of 12 calves born during the exposure period and without tick control, four became theilerial reactors and one died. The application of acaricidal tags however, reduced tick infestation levels considerably compared with untagged controls but did not prevent transmission of theileriosis with the possible exception of tags on Group 4. A number of transient low grade fevers were noted and attributed to Theileria sp., Ehrlichia bovis, Ehrlichia (Cytoecetes) ondiri and Borrelia theileri infections, none of which were fatal. One immunised animal died of acute dual infection of Babesia bigemina and Borrelia theileri after acaricide control by spraying was re-introduced but no Anaplasma infections were detected. An analysis of the economic effects of immunisation was made. 相似文献
4.
J J De Castro A S Young R D Dransfield M P Cunningham T T Dolan 《Research in veterinary science》1985,39(3):279-288
Boran (Bos indicus) heifers were immunised by infection with local Theileria parva parva, T p lawrencei and T mutans stocks and treated with parvaquone and later exposed to natural tick and tick-borne disease challenge in the Trans-Mara Division of Kenya. The Theileria species parasites in the challenge were maintained in African buffalo and cattle and the tick vectors were supported by several species of wild Bovidae and domestic livestock present in the area. Thirty immune cattle were observed for 30 weeks while grazing on a ranch in the Trans-Mara Division. Of these, 15 were immersed in toxaphene at weekly or twice-weekly intervals while 15 cattle remained without acaricide application. Cattle which became pregnant were withdrawn from the experiment. There was no evidence of any clinical tick-borne disease in either group of cattle during the experiment. Five species of ixodid ticks infested the cattle during the experiment and cattle which were not treated with acaricide had far more ticks. Rhipicephalus appendiculatus was the most abundant tick species, with a mean infestation of 46 adults per animal in the undipped cattle. This tick also appeared to be the cause of the observed reduction in weight gains. Major haematological parameters did not differ significantly between the groups. Behavioural studies showed that the undipped cattle spent less time grazing and ruminating. This study has shown that, at the expense of some loss in productivity, zebu cattle, immunised against ticks and theileriosis, can be kept despite tick infestation. 相似文献
5.
H T Koch L Kambeva J G Ocama F C Munatswa F F Franssen G Uilenberg T T Dolan R A Norval 《Veterinary parasitology》1990,37(3-4):185-196
Theileria parva bovis isolates were tested for their immunizing capacity under natural field challenge on Willsbridge Farm in the highveld of Zimbabwe. Fifteen susceptible Sussex yearlings were immunized with the Boleni stock and 15 with a mixture of three isolates from the farm, using tick-derived sporozoite stabilates. No chemoprophylaxis was used. A dose of 0.1 ml of stabilate appeared to be safe in preliminary laboratory experiments, but the reactions were severe in the Sussex cattle and one died despite treatment. Twenty-nine immunized animals and 10 controls first experienced a mild infection, starting about 15 days after their arrival at the farm. Ten of the immunized animals and four controls had schizonts in peripheral lymph nodes for variable periods; one third of those had pyrexia. Nymphal Rhipicephalus appendiculatus ticks applied to three of the reacting immunized calves transmitted Theileria taurotragi to two animals and T. parva to a third. A second Theileria infection, due to T. parva bovis, was detected shortly after the first one. Schizonts were detected in seven out of 10 controls. Pyrexia was more severe and prolonged. Two of the controls died of theileriosis. At the same time schizonts were seen in three immune animals and eight of them had short periods of pyrexia. Intercurrent infections with Babesia bigemina, Borrelia theileri and Eperythrozoon were detected and may have contributed to the fever. Tick infestations were low during the exposure. In the second year of exposure, four out of eight new control animals had severe reactions, and one died. None of the immunized animals became ill, but one animal from the first year control group, which had not reacted previously, had clinical theileriosis. It is concluded that immunization provided an effective protection against field challenge. 相似文献
6.
Kivaria FM Heuer C Jongejan F Okello-Onen J Rutagwenda T Unger F Boehle W 《The Onderstepoort journal of veterinary research》2004,71(3):189-195
A population-based study was carried out on the Ankole ranching scheme in south-west Uganda with the aim of determining the endemic status of Theileria parva infections. For this purpose, the age-related sero-prevalence of T. parva and the specific calf mortality associated with the parasite were assessed. Blood samples were collected from 931 Ankole calves of up to 12 months of age from 81 randomly selected herds. The relationship between rainfall pattern and whole-body Rhipicephalus appendiculatus counts was determined. The influence of tick control practices on East Coast fever-related calf mortality, and sero-positivity were also determined. A significant (r2 = 0.76, P = 0.000) association between R. appendiculatus counts and rainfall was observed. There was no significant (P > 0.05) association between theileriosis-related calf mortality, sero-positivity and the different tick control practices. Antibody prevalence based on the PIM ELISA was above 70% among calves of 6 months of age in 96% in all the herds. Theileria parva-related calf mortality determined by repeated herd visits and farm records ranged between 0 % and 5.4 %. It was concluded that endemic stability for theileriosis, caused by T. parva, existed in the study area, and that the risk of the occurrence of economically important outbreaks of East Coast fever in indigenous cattle was regarded as minimal under the prevailing conditions. 相似文献
7.
J. J. Mutugi A. S. Young D. P. Kariuki J. M. Ole Tameno S. P. Morzaria 《Tropical animal health and production》1991,23(2):75-82
Thirty-seven high grade cattle were immunised against Corridor disease (Theileria parva lawrencei infection) on a farm with a history of heavy and often lethal theilerial challenge. Nineteen cattle were immunised by treating with two doses of long-acting oxytetracyclines given at 20 mg/kg on days 0 and 4 after sporozoite stabilate inoculation, while the other 18 were treated with naphthoquinone buparvaquone, given as a single dose of 2.5 mg/kg simultaneously with stabilate inoculation. All the cattle underwent subclinical theilerial reactions with all but two developing high antibody titres on the IFAT test against T. parva schizont antigen by day 35 after the immunisation. Both buparvaquone and long-acting oxytetracycline appeared equally effective in the immunisation. To date, 26 months later, only two cases of theileriosis parasitologically characteristic of T. p. parva have been reported in the immunised cattle. Following the two cases, investigations showed that when uninfected Rhipicephalus appendiculatus nymphal ticks were deliberately fed on healthy resident cattle on the farm, the resultant adult ticks transmitted acute and lethal theilerial infections to five out of five susceptible cattle. The resultant infections were parasitologically characteristic of T. p. parva infections. Furthermore, the monoclonal antibody profiles of schizont infected cell lines from these infections appeared to be characteristic of T. p. parva. It was thus concluded that resident cattle on the farm could be a potential source of T.p. parva infection which had broken through the immunity of T.p. lawrencei immunised cattle and could constitute a reservoir of theilerial infection for ticks and hence to susceptible stock on the farm. 相似文献
8.
B. H. Fivaz R. A. I. Norval J. A. Lawrence 《Tropical animal health and production》1989,21(2):129-134
Four crossbred Bos taurus oxen resistant to Rhipicephalus appendiculatus and three tick naive oxen of the same breed, which were all infested with adult R. appendiculatus infected with the Boleni strain of Theileria parva bovis, acquired Theileria infection. All four tick resistant oxen recovered after a mild febrile reaction. Two of the tick naive oxen died while the third recovered after a protracted period. It is suggested that tick resistance in cattle may be an important factor in establishing and maintaining enzootic stability in Theileria endemic areas. 相似文献
9.
A C Maritim A S Young A C Lesan S G Ndungu D A Stagg P N Ngumi 《Veterinary parasitology》1992,43(1-2):1-14
A sporozoite stabilate (St. 199) of Theileria parva was obtained by feeding nymphal Rhipicephalus appendiculatus on an African buffalo (Syncerus caffer) and was used to immunize cattle by the infection and treatment method. Nymphal ticks were applied to one of the steers 90 days later and it was shown that the resultant adult tick had become infected. Using tick/cattle passage, two passage lines of T. parva were established. By the fifth tick/cattle passage, the parasite stocks had changed their behaviour to that of T. parva derived from cattle as the parasite produced relatively high schizont parasitosis and piroplasm parasitaemia in cattle, and had become highly infective to ticks. At various passage levels the parasite populations were characterized by behaviour and by monoclonal antibodies against T. parva schizonts using infected cell culture isolates from cattle during acute infections. The monoclonal antibody profile showed little evidence of antigen change of the parasite during passage through cattle, which was confirmed in a two-way cross-immunity experiment using sporozoite stabilate derived from ticks obtained from the buffalo and fourth passage in cattle. The implication of these results, particularly in relationship to immunization of cattle against T. parva derived from buffalo, is discussed. 相似文献
10.
Walker AR Katzer F Ngugi D McKeever D 《The Onderstepoort journal of veterinary research》2006,73(2):157-162
Experimental transmissions of cloned Theileria parva in cattle with Rhipicephalus appendiculatus ticks were compared to transmissions with uncloned T. parva during studies on the potential for genetic recombination during syngamy of Theileria to produce antigenic diversity for evasion of bovine immunity. Prevalence and abundance of T. parva infection in adult ticks, which resulted from the feeding of nymphs on the calves, were significantly higher in the uncloned compared to the cloned T. parva. Development of sporoblasts of T. parva in the ticks to produce infective sporozoites was similar. There was no statistically significant difference in the clinical course of infection in cattle between cloned and uncloned T. parva. It was concluded that cloned T. parva has characteristics that reduce its viability during the tick stages of its life cycle. 相似文献
11.
12.
Three cattle, which had been experimentally infected with Theileria parva lawrencei and maintained as carriers of the infection, were each infested simultaneously with clean nymphal Rhipicephalus appendiculatus and Rhipicephalus zambeziensis in ear bags on separate ears. After moulting, the ensuing adult ticks were fed on rabbits for 4 days and their salivary glands were examined for infective stages of the parasite. Microscopic examination revealed significantly higher infection rates in the salivary glands of R. zambeziensis than in R. appendiculatus which may indicate an increased vector efficiency of R. zambeziensis for T. p. lawrencei. 相似文献
13.
Immunization of cattle with nymphal Hyalomma anatolicum anatolicum extracts: effects on tick biology
Antigens derived from partially engorged nymphs of Hyalomma anatolicum anatolicum were used in immunizing crossbred (Bos indicus×Bos taurus) cattle against larval, nymphal and adult H. a. anatolicum and H. dromedarii. The cattle were either infected with Theileria annulata at low parasitaemia or were uninfected. Whole nymphal extract (WNE), nymphal membrane antigens (NMA) and nymphal soluble antigens (NSA) were used for immunization. The group immunized with WNE showed significant and better rejection of H. a. anatolicum ticks as compared to calves immunized with either NMA or NSA. The moulting rates of both engorged larvae and nymphs remained unaffected. Nymphs which engorged on the immunized calves were fully susceptible to infection by T. annulata as indicated by the intensity and abundance of Theileria infections in the resulting adult ticks from immunized and unimmunized Theileria infected cattle. These ticks also transmitted fatal theileriosis to susceptible calves. 相似文献
14.
Thirty-one calves born into five Maasai zebu cattle herds over a period of 1 month in the Trans-Mara Division of Kenya, endemic for theileriosis, were recruited for an intensive study of theileriosis. No calves up to 6 months of age died but all developed Theileria infections as judged by slide examination and serology. Parasitosis by T. mutans schizonts in lymph node smears was usually higher than that of T. parva. The T. mutans schizonts usually occurred at an earlier age but persisted at a patent level for a shorter time than those of T. parva. Serological findings using the indirect fluorescent antibody test confirmed the parasitological findings. It was evident that colostral transfer of Theileria antibodies was frequent. Theileria piroplasm parasitaemia had developed in all calves by 111 days of age. The earlier parasitosis by T. mutans reflected the higher infection rates in Amblyomma spp. than in Rhipicephalus appendiculatus. The mean number of R. appendiculatus on the ears of calves during the observations was 9.1 adults and 1.5 nymphs. Clinical episodes of T. mutans and T. parva infection were associated with febrile responses, enlarged lymph nodes, anaemia and other symptoms and about 80% of calves had poor weight gains or weight losses during either clinical infection. It would appear that theileriosis is one of the most important factors in the stunting of calf development in the area. 相似文献
15.
Parasitic diseases, like babesiosis and theileriosis are transmitted by ticks: their occurrence is therefore linked to the size of the tick stock and the seasonality of the vectors. Babesia divergens bovine babesiosis transmitted by Ixodes ricinus is widespread and often reported in France. Serological prevalence is high, ranging from 20 to 80% according to the farms. Clinical incidence is low: around 0.4% for the whole cattle population. The endemic situation is unstable and clinical cases occur more frequently with farming system modifications. L. ricinus is a tick essentially found in woodlands and so, for the most part, is found in closed rural areas. The situation of the other bovine babesiosis (Babesia major) and theileriosis (Theileria orientalis) is not well documented in France. However, the epidemiology of parasitic diseases is changing, especially because of changes in the environmental characteristics, i.e. both farm and herd management conditions and also climatic conditions. These modifications can provoke an increase in the tick stocks, an increase in the contact rate between cattle and ticks, and an increase in the contact rate between cattle and the wild fauna, especially deer. This results in likely modifications of the endemic situation, with a higher risk of clinical babesiosis in the medium term. 相似文献
16.
Marcotty T Brandt J Billiouw M Chaka G Losson B Berkvens D 《Veterinary parasitology》2002,110(1-2):45-56
Immunisation of calves by the infection and treatment method (I & T) has been extensively used in the eastern province of Zambia to control East Coast fever (ECF), a protozoan tick-borne disease. This paper presents the results of a field longitudinal study, which included a total of 148 Angoni calves. After immunisation against ECF, they were monitored for a full rainy season, coinciding with the main peak of activity of the vector of Theileria parva, the tick Rhipicephalus appendiculatus. Dysimmunisation (acute reaction generated by I & T immunisation), seroconversion and mortality are among the parameters recorded. The effect of maternal antibodies on these parameters was analysed and also studied in experimental conditions on two calves. Before immunisation, young calves had a higher seroprevalence than older animals (maternal antibodies) but their post-immunisation seroprevalence was lower. There was no evidence that their immunoprotection was weaker but this indicates that the post-immunisation seroconversion is probably not a reliable tool to monitor the efficacy of calf immunisation. The carrier state of cattle after immunisation was investigated in experimental conditions on three bovines whereas in the field, the infection prevalence in the ticks was estimated using the relation between the tick burden and the T. parva contacts with the calves. The ability of larval and nymphal R. appendiculatus ticks to pick-up T. parva from carriers and to transmit it to na?ve animals after moulting was assessed. It was found that both instars are able to transmit clinical and lethal ECF but that the prevalence of T. parva infection in nymphs is much lower than in adults, confirming the primary role of adults in the transmission of ECF in endemic conditions. Similar results were obtained from the field whereby the ECF peak corresponds with the peak of adult R. appendiculatus activity. The infection prevalence in the ticks was however much lower in the field than in experimental conditions indicating that an important proportion of them feed on alternative hosts. Old ticks seemed to have lost part of their infectivity. 相似文献
17.
Thompson BE Latif AA Oosthuizen MC Troskie M Penzhorn BL 《Journal of the South African Veterinary Association》2008,79(1):31-35
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. 相似文献
18.
Ogden NH Gwakisa P Swai E French NP Fitzpatrick J Kambarage D Bryant M 《Veterinary parasitology》2003,112(3):177-183
The ability of PCR to detect infections of Theileria parva, the cause of East Coast Fever, in field-collected tick and bovine samples from Tanzania was evaluated. PCR-detected infection prevalence was high (15/20, 75%) in unfed adult Rhipicephalus appendiculatus ticks that fed as nymphs on an acutely-infected calf, but low (22/836, 2.6%) in unfed adult R. appendiculatus collected from field sites in Tanzania. Tick infection prevalence was comparable to that in previous studies that used salivary gland staining to detect T. parva infection in field-collected host-seeking ticks. Of 282 naturally-exposed zebu calves, seven had PCR-positive buffy coat samples prior to detection of Theileria spp. parasites in stained buffy coat cells or lymph node biopsies. Evidence of Theileria spp. infections was detected in stained smears of lymph node biopsies from 109 calves (38.6%) and buffy coat samples from 81 (28.7%), while buffy coat samples from 66 (23.4%) were PCR-positive for T. parva. Implications of these findings for the sensitivity and specificity of the PCR are discussed. 相似文献
19.
When groups of Theileria parva parva Muguga-immunized cattle were given a homologous lethal challenge at different times after immunization, it was found that 4/6, 5/6, 6/6 and 6/6 animals survived when challenged on Days 5, 10, 20 and 30, respectively, post-immunization. With a heterologous challenge (T.p.parva Marikebuni), 2/6, 5/6, 4/6, 4/6 and 5/6 cattle survived when challenged on Days 5, 10, 20 and 30, respectively, after immunization. All controls, except one, died of East Coast fever (ECF). The survivor underwent severe ECF and recovered after a prolonged convalescence. When two T.p.parva Muguga-immunized animals were each given homologous challenge by application of 1000 infected ticks (infection rate of 20 infected acini (i.a.) per tick), both survived a mild ECF reaction. When groups of T.p.parva Muguga- or T.p.parva Muguga/Marikebuni-immunized cattle were challenged with different doses of T.p.parva Muguga sporozoites (equivalent of 140, 1400 and 14,000 i.a. per animal), 28/29 cattle survived. All controls died of ECF. It was concluded that cattle could be safely exposed to tick challenge 1 week after immunization by infection and treatment using appropriate immunizing stock(s). Massive homologous challenge did not break through the immunity induced by the immunization procedure. 相似文献
20.
Rhipicephalus zambeziensis was shown experimentally to transmit Theileria parva parva in cattle from nymph to adult and Theileria parva lawrencei, Theileria parva bovis and Theileria taurotragi from larva to nymph and nymph to adult. In a single trial the tick failed to transmit Theileria mutans. The tick is believed to be a vector of T. parva lawrencei in the field in Zimbabwe. 相似文献