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1.
Studies on the pathogenesis of Babesia motasi (Wales) infection following blood transfusion of infected blood to normal or splenectomised recipients showed that the intact animal is refractory to infection but that infection in splenectomised animals caused weight loss, fever, anorexia, lassitude and a macrocytic hypochromic anaemia which coincided with the peak of parasitaemia. There was an initial leucocytosis, largely due to a neutrophilia. The prepatent period following blood transfusion was 2-3 days. Unconjugated and conjugated (direct) bilirubin levels increased from pre-infection levels to peaks of 1.43 and 0.70 mg/100 ml of blood, respectively. Serum glutamic pyruvic acid transaminases (SGPT) increased slightly but serum glutamic-oxaloacetic acid transaminases (SGOT) and blood sugar (glucose) levels did not show significant changes after infection. Total serum protein levels increased temporarily and then returned to normal. Blood urea nitrogen levels increased, with biphasic peaks (76.32 and 86.29 mg/100 ml) on Days 2 and 8 post-patency. Clinical infections even in splenectomised sheep, were mild and of short duration, although recovered sheep remained carriers. 相似文献
2.
Serodiagnosis of Babesia motasi (Wales), Theileria recondita (Wales) and Cytoecetes phagocytophila infection in sheep 总被引：2，自引：0，他引：2
The indirect fluorescent antibody test (IFAT) was used to diagnose some tick-borne infections of sheep, Babesia motasi (Wales), Theileria recondita (Wales) and Cytoecetes phagocytophila. Antigen was prepared from blood derived from splenectomised sheep except for C phagocytophila which was derived from a normal animal. A field survey was made to assess the prevalence of B motasi and T recondita in North Wales and a comparison made between the titres using the B motasi (Wales) antigen with those previously reported. IFA titres reported in the homologous system were consistently lower than those described previously. The results of the field survey suggested that B motasi (Wales) infection is more widespread than was originally thought and more widespread than the known distribution of its vector Haemaphysalis punctata. No serological cross reactions occurred between B motasi (Wales), T recondita (Wales), C phagocytophila, B divergens, Sarcocystis ovicanis and Toxoplasma gondii. 相似文献
3.
Adult Haemaphysalis punctata (Canestrini and Fanzago 1877) collected from an area of rough grazing at Mynydd Mawr, Aberdaron, North Wales, transmitted Theileria recondita (Wales); field-collected nymphs failed to transmit this parasite. Following adult tick infestation, piroplasms were first observed in the blood of splenectomised infested sheep 8 days after tick attachment; the parasitaemia lasted 9 days. The parasite can also be transferred by syringe passage of blood from splenectomised to normal sheep and vice versa. Parasitaemias were higher and of longer duration in splenectomised animals. A rise in parasitaemia was detected in a splenectomised ewe after parturition, 19 months following blood-transmitted infection from which it had recovered clinically. The morphometrics of the piroplasms of T. recondita (Wales) were investigated; the rod and the ring forms were the most common. The mean length of the rod form was 2.09 microns and the mean diameter of the ring form was 1.22 micron. 相似文献
4.
The pathogenicity of Theileria recondita infection in both splenectomised and non-splenectomised sheep was investigated. Following transmission of T. recondita to splenectomised animals both by adult ticks and blood transfusion a fever and severe macrocytic hypochromic anaemia developed which lasted the 9 days or more of patent infection. The prepatent period following tick attachment was about 8 days, but was variable following blood transfusion. Infection of normal animals caused a transient macrocytic hypochromic anaemia and slight fever which lasted throughout the period of low parasitaemia (7 days). The increase in mean cell volume was due to an increase in numbers of juvenile red cells in the peripheral blood. There was a transient neutrophilia and lymphocytopenia but no significant changes in thrombocyte or leucocyte numbers. 相似文献
5.
Experiments on the transmission of an unidentified Theileria sp. infective for small ruminants by Haemaphysalis qinghaiensis and Hyalomma anatolicum anatolicum were carried out. Three Theileria-free batches of adult, larvae, and nymphs of laboratory reared H. qinghaiensis and Hy. a. anatolicum ticks were infected by feeding them on sheep infected with Theileria sp. The Theileria sp. was originally isolated from adult ticks of H. qinghaiensis, by inoculation of blood stabilates or tick transmission. H. qinghaiensis has been shown to be capable of transmitting the Theileria sp. infective for small ruminants transstadially to sheep and goats. The nymphs developed from the larvae engorged on the sheep infected with the parasite transmitted the pathogen to splenectomized sheep with prepatent periods of 30, 31 days, respectively; but the subsequent adult ticks of H. qinghaiensis derived from the nymphs did not transmit the pathogen to sheep. However, adults developed from the nymphs engorged on the sheep infected with the parasite transmitted the pathogen to sheep with prepatent periods of 24-27 days. The larvae, nymphs and adult ticks derived from female H. qinghaiensis ticks engorged on infected sheep were not able to transmit the parasite transovarially. The same experiments were done with Hy. a. anatolicum, but examination for presence of piroplasma of Theileria sp. from all animals were negative, demonstrating that Hy. a. anatolicum could not transmit the organism to sheep or goats. 相似文献
6.
OBJECTIVE: To assess the efficacy of ivermectin and moxidectin to prevent transmission of Babesia bovis and Babesia bigemina by Boophilus microplus to cattle under conditions of relatively intense experimental challenge. DESIGN: Naive Bos taurus calves were treated with either pour-on or injectable formulations of either ivermectin or moxidectin and then exposed to larvae of B microplus infected with B bovis or larvae or adults of B microplus infected with B bigemina. One calf was used for each combination of haemoparasite, B microplus life stage, drug and application route. PROCEDURE: Groups of calves were treated with the test drugs in either pour-on or injectable formulation and then infested with B microplus larvae infected with B bovis or B bigemina. B bigemina infected adult male ticks grown on an untreated calf were later transferred to a fourth group of animals. Infections were monitored via peripheral blood smears to determine haemoparasite transmission. RESULTS: Cattle treated with either pour-on or injectable formulations of ivermectin and moxidectin became infected with B bovis after infestation with infected larvae. Similarly, larvae infected with B bigemina survived to the nymphal stage to transmit the haemoparasite to animals treated with each drug preparation. Cattle treated with pour-on formulations of ivermectin and moxidectin then infested with adult male ticks infected with B bigemina did not become infected with B bigemina whereas those treated with the injectable formulations of ivermectin and moxidectin did show a parasitaemia. CONCLUSIONS: Injectable or pour-on formulations of ivermectin and moxidectin do not prevent transmission of Babesia to cattle by B microplus. Use of these drugs can therefore not be recommended as a primary means of protecting susceptible cattle from the risk of Babesia infection. 相似文献
7.
Oliveira MC Oliveira-Sequeira TC Regitano LC Alencar MM Néo TA Silva AM Oliveira HN 《Veterinary parasitology》2008,155(3-4):281-286
Babesia bigemina infections were investigated in four genetic groups of beef cattle and in Rhipicephalus (Boophilus) microplus engorged female ticks. Blood samples and engorged female ticks were collected from 15 cows and 15 calves from each of the following genetic groups: Nelore, Angus x Nelore, Canchim x Nelore, and Simmental x Nelore. Microscopic examination of blood smears and tick hemolymph revealed that merozoites of B. bigemina (6/60) as well as kinetes of Babesia spp. (9/549) were only detected in samples (blood and ticks, respectively) originated from calves. PCR-based methods using primers for specific detection of B. bigemina revealed 100% infection in both calves and cows, regardless the genetic group. Tick infection was detected by nested-PCR amplifications showing that the frequency of B. bigemina was higher (P<0.01) in female ticks collected from calves (134/549) than in those collected from cows (52/553). The frequency of B. bigemina was similar in ticks collected from animals, either cows or calves, of the four genetic groups (P>0.05). 相似文献
8.
Two African buffalo (Syncerus caffer), an eland (Taurotragus oryx) and a waterbuck (Kobus defassa) were intravenously inoculated with Cowdria ruminantium (Kiswani). Amblyomma gemma nymphs were fed on the animals at 3 weekly intervals. Jugular blood was also collected at 3 weekly intervals and inoculated into sheep. Nymphal ticks that fed on one buffalo on days 16 and 37 and on the other buffalo on day 58 after infection transmitted the disease as adults to sheep. Nymphs that were applied to the eland 16 days after infection also transmitted the disease to sheep. No nymphs that had fed on the waterbuck transmitted the disease. This is the first report of transmission of heartwater by Amblyomma gemma from infected wild ruminant species to a susceptible domestic ruminant species. 相似文献
9.
SUMMARY: Boophilus microplus ticks collected from calves with patent Anaplasma marginale infections were incubated at either 4 to 5°C, 14°C, 22°C, 27°C or 37°C for up to 14 days. Extracts prepared either from larvae, nymphs, immature females, adult males or mixtures of both sexes were infective for 14 of the 16 splenectomised calves inoculated. Extracts either from nymphs or from adult ticks deriving from nymphs moulted in vitro were infective for 11 of 12 nonsplenectomised calves. Possible application of the findings to producing a vaccine strain of A. marginale is discussed. 相似文献
10.
Boophilus microplus infected with Babesia bovis were transferred artificially from one splenectomised calf to another during each moult in the parasitic life cycle of the tick. Eggs from the engorged female ticks recovered at the end of the cycle were incubated and the resulting larvae used to infest more splenectomised calves. Babesia bovis was transmitted only by the original larvae used at the commencement of the experiment and it was concluded that the protozoan parasite did not persist in an infective form in the ticks beyond the larval stage. 相似文献
11.
Summary A large Babesia species occurs in sheep on the North Sea islands of the Netherlands. The tick Haemaphysalis punctata is a vector. Its pathogenicity appears to be low. It is morphologically similar to a Turkish strain, considered to be B. motasi, which is also transmitted by Haemaphysalis ticks. It differs from the Turkish parasite serologically as well as in cross-immunity tests and in not being effective to goats. There may be a group of morphologically similar parasites with serological differences and different infectivity for sheep and goats. As it is impossible to know which one is to be considered as the original B. motasi, we designate the Dutch parasite as B. motasi (Netherlands). Anaplasma mesaeterum was found to occur on the island of Texel as well as on Ameland, where it had been found initially. 相似文献
12.
Haemaphysalis qinghaiensis ticks transmit at least two different Theileria species: one is infective to yaks,one is infective to sheep 总被引：8，自引：0，他引：8
Yin H Guan G Ma M Luo J Lu B Yuan G Bai Q Lu C Yuan Z Preston P 《Veterinary parasitology》2002,107(1-2):29-35
Adult Haemaphysalis qinghaiensis ticks from Gannan area, where ovine theileriosis is prevalent but bovine theileriosis has not been reported, transmitted Theileria parasites to yaks and sheep. Blood from the infected yak contained Theileria parasites that were infective to yaks, but not sheep. In contrast, blood from the infected sheep did not contain Theileria parasites infective to yaks. These results suggested that the ticks from the Gannan area were infected with two species of Theileria one which specifically parasitises yaks, one which parasitises sheep. Both infections were more aggressive in splenectomised hosts as compared to intact host. Adult H. qinghaiensis ticks from Zhanjiachuan area, where ovine theileriosis is prevalent but where no yaks are raised, transmitted Theileria parasites to ovine, but not yaks. Taken together these results indicate that H. qinghaiensis ticks may be infected with two different Theileria species. The species infective for sheep could be related to the newly recognised, but not yet named, pathogen recently reported in small ruminants in China. The species infective for yaks appears to be benign and is morphologically similar to parasites of the Theileria sergenti/orientalis/buffeli group. 相似文献
13.
The prevalence of Babesia spp. infection was studied in sheep of the Mashhad area in Iran from 1998 to 2000. A total of 677 sheep originating from 115 flocks were clinically examined and investigated for the presence of Babesia spp. in appropriate blood smears and any tick species on the body of the animals. The study revealed that the infection rate for Babesia ovis and Babesia motasi were 167 (24.6%) and 4 (0.5%), respectively. Double (mixed) infections occurred in 21 (3%) sheep. Differences in infection rates were statistically non-significant between male and female sheep and between different age groups. Seasonally, the prevalence of Babesia spp. infection started to increase in April and reached highest values in August (56%), while a decrease was observed in September, reaching the lowest levels In February and March. The study demonstrated that 1.7% of sheep infected with B. ovis and 50% of sheep infected with B. motasi exhibited clinical signs. Sheep infected with B. motasi showed the highest levels of parasitemia. We found that 550 (73%) of the animals harbored Rhipicephalus sanguineus; 166 (21%) Hyalomma marginatum; 19 (2.5%) Dermacentor daghestanicus; 14 (1.8%) Hyalomma anatolicum; 6 (0.66%) Hyalomma asiaticum; and one (0.13%) Haemaphysalis punctata. The examination of 727 tick haemolymph samples and 52 tick egg smears showed that one sample (0.2%) of haemolymph of R. sanguineus, two (1.2%) haemolymphs of H. marginatum and two (2%) eggs of R. sanguineus harbored kinetes morphologically matching the criteria described for B. ovis. 相似文献
14.
Laboratory-reared larval Gulf Coast ticks (GCTs) (Amblyomma maculatum) were exposed experimentally and found to acquire Hepatozoon americanum infection while feeding on parasitemic dogs. These ticks supported gamogonic and sporogonic development of the apicomplexan, and oocysts from newly molted nymphs were infectious for a dog. Other nymphs from this cohort that were allowed to feed on a blood-parasite naive sheep molted normally; the resulting adult ticks contained oocysts that were infectious for another dog. Merogonic development of H. americanum in the dogs and the resulting lesions/disease appeared similar, irrespective of whether infectious oocysts were derived from nymphal or adult ticks that acquired infection as larvae. In the system previously known, nymphal ticks acquire infection and adults harbor infective oocysts, which vertebrate hosts ingest. Given that larval A. maculatum can acquire infection and nymphs can harbor viable oocysts as demonstrated by this study, the potential variety of vertebrate hosts that can alternate with GCTs in maintaining an endemic cycle is considerably expanded. 相似文献
15.
The development and morphology of Babesia bigemina in the gut of Boophilus microplus ticks were studied during laboratory maintenance of the babesia by four methods: tick transmission in unsplenectomised (intact) calves; tick transmission in splenectomised calves; syringe passage at intervals of five days or less in splenectomised calves; and syringe passage at intervals of six weeks or more in intact calves. The first method had no apparent effect on the development of B bigemina in ticks compared to that of the original isolate. The other three methods had obvious effects, the most pronounced being increased numbers of babesial forms with processes, particularly during early stages of development. The findings emphasise the importance of maintaining laboratory strains of parasites by natural means in life cycle studies. 相似文献
16.
Observations were made on the effects of five different methods of laboratory maintenance on the infectivity and virulence of Babesia bigemina for the tick Boophilus microplus. The original isolate was highly infective and virulent, causing premature death of engorged female ticks and reduced egg production. Maintenance of the strain by syringe passage in unsplenectomised calves at six to 10 week intervals reduced both its infectivity and virulence for ticks. When slow passages were preceded by a series of rapid passages in splenectomised calves, the changes to the strain were less pronounced. The other three procedures, rapid syringe passage in splenectomised calves and tick passage in either splenectomised or intact calves, had no statistically significant effect on the characteristics measured. 相似文献
17.
甘肃省部分牛羊血液原虫传播媒介的实验研究 总被引：4，自引：0，他引：4
利用蜱传播试验,确定了甘肃省一些牛羊血液原虫的媒介和传播方式。甘肃省牛的双芽巴贝斯虫媒介为微小牛蜱。大巴贝斯虫媒介为长角血蜱。瑟氏泰 勒虫媒介为长角血蜱;绵羊无浆体的媒介为草原革蜱。微小牛蜱、长角血蜱可分别传播双芽巴贝斯虫和大巴贝斯虫,传播方式为经卵传递。将采集于甘肃文县牛体上的微小牛蜱和两当县的长角血蜱饱血雌虫孵育而来的次代幼虫分别叮咬除脾牛体后,２头牛各自感染双芽巴贝斯虫或大巴贝斯虫。将采自崇 相似文献
18.
Summary A large Babesia species occurs in sheep on the North Sea islands of the Netherlands. The tick Haemaphysalis punctata is a vector. Its pathogenicity appears to be low. It is morphologically similar to a Turkish strain, considered to be B. motasi, which is also transmitted by Haemaphysalis ticks. It differs from the Turkish parasite serologically as well as in cross‐immunity tests and in not being effective to goats. There may be a group of morphologically similar parasites with serological differences and different infectivity for sheep and goats. As it is impossible to know which one is to be considered as the original B. motasi, we designate the Dutch parasite as B. motasi (Netherlands). Anaplasma mesaeterum was found to occur on the island of Texel as well as on Ameland, where it had been found initially. 相似文献
19.
C. HAMBLIN JS SALT SD GRAHAM K. HOPWOOD AM WADE-EVANS 《Australian veterinary journal》1998,76(9):622-629
Objective To study the clinical signs following bluetongue virus serotypes 1 and 3 infection in Poll Dorset sheep.
Design A clinical and pathological study.
Procedure Twenty Poll Dorset sheep were inoculated with bluetongue virus serotypes 1 or 3, each inoculum having a different passage history. The sheep were examined daily and their clinical appearance and rectal temperatures recorded. Heparinised and non-heparinised blood samples were taken at intervals for virological and serological study. Gross pathological findings were recorded for several sheep at necropsy and tissue samples were collected from three sheep for virological studies.
Results All inoculated sheep developed clinical disease. The clinical signs and gross pathological changes varied considerably but were consistent with damage to the vascular endothelial system. There was a decline in the titres of infectious bluetongue virus and of antigen in tissues collected between 7 and 12 days after infection.
Conclusions The severity of disease was related to the speed of onset and duration of pyrexia and not the development or titre of viraemia. Generally, those animals with sensitive mouths, depression, coronitis, recumbency and reluctance to move were the most debilitated. Whole blood was the most reliable source of infectious virus from acutely and chronically infected and convalescent animals. However, tissue samples particularly spleen, collected from dead or killed animals suffering from either peracute or acute forms of disease were most appropriate for the rapid confirmation of a clinical diagnosis. 相似文献
Design A clinical and pathological study.
Procedure Twenty Poll Dorset sheep were inoculated with bluetongue virus serotypes 1 or 3, each inoculum having a different passage history. The sheep were examined daily and their clinical appearance and rectal temperatures recorded. Heparinised and non-heparinised blood samples were taken at intervals for virological and serological study. Gross pathological findings were recorded for several sheep at necropsy and tissue samples were collected from three sheep for virological studies.
Results All inoculated sheep developed clinical disease. The clinical signs and gross pathological changes varied considerably but were consistent with damage to the vascular endothelial system. There was a decline in the titres of infectious bluetongue virus and of antigen in tissues collected between 7 and 12 days after infection.
Conclusions The severity of disease was related to the speed of onset and duration of pyrexia and not the development or titre of viraemia. Generally, those animals with sensitive mouths, depression, coronitis, recumbency and reluctance to move were the most debilitated. Whole blood was the most reliable source of infectious virus from acutely and chronically infected and convalescent animals. However, tissue samples particularly spleen, collected from dead or killed animals suffering from either peracute or acute forms of disease were most appropriate for the rapid confirmation of a clinical diagnosis. 相似文献
20.
To screen the host-dependent abundance of hard tick (Acari: Ixodidae) developmental stages on ruminants in South Hungary, red and roe deer, as well as goats and sheep were examined in a season, when larvae and nymphs are active. Altogether 2271 ticks were collected. In the relevant period the prevalence of tick-infestation was significantly higher among goats, than among sheep kept in the very same area, most likely in association with the browsing habit of the former. Roe deer and goats were found to be important hosts for Ixodes ricinus and Haemaphysalis concinna larvae, in contrast to the view that this stage does not usually feed on medium-sized mammals. Interestingly, one third of I. ricinus larvae and one larva of H. concinna and of Dermacentor reticulatus collected from goats in the same herd in August have started the moulting process (showed apolysis) on their host, despite being three-host ticks. This is the first survey involving four species of domestic and wild ruminants in Europe to compare the host-preference of ixodid ticks in the same region. 相似文献