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1.
Morbidity and mortality due to Babesia ovis in sheep flocks grazing in an enzootic area of Israel occur yearly, about 2 weeks after detection of adult Rhipicephalus bursa ticks on the animals. Disease incidence peaks in May, but lasts throughout the active period of the adult ticks in the spring-summer months of April–July. No clinical cases of babesiosis have been registered during the active period of the preimaginal stages of R. bursa, from October to February. Incidence of parasitaemia during the spring-summer months was variable, ranging between 2 and 25%. However, in the winter months the incidence of parasitaemia in hoggets increased considerably, reaching 4–60% of the animals.

A positive serological response to B. ovis was found in 84.5% of the hoggets and 88.9% of the ewes. In ewes, the prevalence of the serological response showed no marked seasonal variations. Colostral sera of 67.5% and 75% of the ewes and hoggets, respectively, were serologically positive for B. ovis. No antibodies were detected in the sera of lambs less than 3–4 months of age. The epizootiology of sheep babesiosis appears to differ from that of bovine babesiosis.  相似文献   


2.
Cattle, sheep, goats, and horses in most areas of Barbados were examined for ticks. About 68% of the cattle, mostly Holstein dairy cows, and 23% of the sheep, mostly purebred or crossbred black belly sheep, were infested with the southern cattle tick, Boophilus microplus (Canestrini), a vector of bovine babesiosis and anaplasmosis. About 13% of the horses were infested with the tropical horse tick, Anocentor nitens (Neumann), a vector of equine babesiosis. Cattle owners used a variety of acaricides as dusts, sprays, or washes on their cattle for the control of ticks.  相似文献   

3.
A total of 124 blood samples were collected from 92 sheep and 32 goats from 21 randomly selected herds located in two regions of Greece. Data on the characteristics of the animals (species, gender, age, tick burden, presence of haemoglobinuria, prior treatment for babesiosis) and the herd (location, size, species of animals, dogs associated with the herds, tick burden of dogs associated with the herds) were collected through questionnaires. Nineteen animals (15%) produced the DNA fragment specific for Babesia of which 16 were sheep and three were goats. Nucleotide sequence of PCR products revealed 100% homology with Babesia ovis 18S rRNA gene. Nine farms (43%) were found positive for B. ovis. The percentage of positive animals in each farm varied between 10 and 61%. The relative risk of the presence of ticks in sheep and goats (p<0.01) and farm dogs (p<0.01) for PCR-positive results for B. ovis in sheep and goats was found 6.63 and 4.14, respectively.  相似文献   

4.
1986年从病牛身上摘下饱血雌蜱,经实验室饲养,孵化为第二代成蜱,人工越冬。于1987年将上述蜱100只接种于已去脾23天的一岁龄健康水牛,以后每天从该牛身上取蜱查其唾液腺。结果在吸血期间,始终查到梨形虫体,其平均大小为1.3×0.68微米。接种后第4天,牛血中开始出现巴贝斯虫,至第19天,红细胞感染率高达9.6％,单梨形虫体大小为0.84～2.64×0.42～1.22微米,双梨形虫体大小为0.64～1.64×0.37～0.97微米,以后逐渐下阵。该牛出现体温升高)41.6℃)、严重贫血(血红蛋白量2克,红细胞压积14％,红细胞总数177万/毫米~3)、黄疸及精神萎顿等症状。上述结果表明,该牛感染了巴贝斯虫病,由此证实镰形扇头蜱是经卵传递巴贝斯虫,其感染阶段是成蜱。  相似文献   

5.
Bovine babesiosis is responsible for serious economic losses in Uruguay. Haemovaccines play an important role in disease prevention, but concern has been raised about their use. It is feared that the attenuated Babesia bovis and Babesia bigemina vaccine strains may be transmitted by the local tick vector Boophilus microplus, and that reversion to virulence could occur. We therefore investigated the possibility that these strains could be transmitted via the transovarial route in ticks using a Babesia species-specific polymerase chain reaction (PCR) assay. DNA was extracted from the developmental stages of the tick vector that had fed on calves immunized with the haemovaccine. It was possible to detect Babesia DNA not only in adult ticks, but also in their eggs and larvae. In addition, it was shown that calves infested with larvae derived from eggs laid by ticks fed on acutely infected calves, were positive for Babesia using PCR. Caution should therefore be shown with the distribution of the haemovaccine in marginal areas. It is still advisable that suitable tick control measures be used to prevent transovarial transmission and the potential risk of attenuated Babesia reverting to virulence.  相似文献   

6.
Abstract

The distribution of ticks is increasing in many parts of the world, including Norway. It has been suggested that this is linked to climate change while the role of different land use practices appears less clear. Here, we investigate the variation in abundance of questing ticks on the west coast of Norway and relate this to the presence of sheep, a tick host that also modifies the landscape through grazing. We found that questing tick abundance was higher in areas without sheep, suggesting that sheep alter vegetation in turn reducing tick survival. However, we cannot exclude that other mechanisms may also lead to reduced abundance of questing ticks; sheep may negatively affect the local density of red deer which is an important alternative host. In any case, sheep farming may contribute to limiting the local abundance of questing ticks and related diseases.  相似文献   

7.
Gao J  Luo J  Fan R  Guan G  Ren Q  Ma M  Sugimoto C  Bai Q  Yin H 《Veterinary parasitology》2007,147(1-2):140-149
There should be some differences between antibodies generated by feeding ticks on animals and those derived by immunizing animals with tick extracts. Here, we found serum collected from sheep immunized with Haemaphysalis qinghaiensis salivary gland extracts could detect two more protein bands with molecular weights of 22 and 37 kDa (P22 and P37) on Western blots of extracts of tick salivary glands than serum from tick infected animals. Rabbit anti-H. qinghaiensis differential protein immune serum was then generated from P22 and P37 and was used to immunoscreen a cDNA library constructed from salivary glands, Malpighian tubules and ovaries of partially engorged H. qinghaiensis. A cDNA contains an open reading frame of 483 bp that codes for 160 amino acid residues with a coding capacity of 18 kDa was cloned and designated Hq02. Expression analysis by RT-PCR showed that this gene is expressed in salivary glands, midguts, other organs and different developmental stages of H. qinghaiensis. The predicted amino acid sequence of the Hq02 gene had high homology to some known myosin alkali light chain (MLC) proteins. A fusion protein consisting of 130 amino acids of Hq02 protein and 335 amino acids of T7 gene 10 protein was expressed in Escherichia coli and used to immunize sheep. Western blot showed that only rabbit anti-H. qinghaiensis differential protein immune serum could recognize the expressed Hq02 protein, while rabbit anti-H. qinghaiensis saliva immune could not. This proved Hq02 protein was a "concealed" antigen. Immunization with the recombinant Hq02 conferred a 21.8% reduction of engorgement weight for adult female ticks that fed on the immunized sheep. This is the first report of tick myosin alkali light chain and the function of this protein is discussed.  相似文献   

8.
An accumulation of autochthonous cases of canine babesiosis caused by Babesia canis has been registered in a small animal clinic in the Saarland since the beginning of 2006, some cases with fatal outcome. This study aims to contribute to the explanation of strong focal occurrence of infections with B. canis in this region.Therefore, patient owners who had presented their dogs in the years 2006 and 2007 because of babesiosis and who had claimed not having left the Saarland with their dogs at least six months before the outbreak of Babesiosis, were asked for their dog walking habits. Accordingly, a selection often tick collection sites of various landscape structures was made.Tick sampling by flagging the vegetation took place every month from March to December 2008. The collected ticks were identified morphologically. In eight of ten collecting sites a total of 397 adult Dermacentor reticulatus ticks were collected from March to December with the highest frequencies during the months of May, October and November. All collected specimens were examined by genus-specific conventional PCR for the presence of Babesia-DNA. In positive samples, the PCR-products were differentiated by sequencing. ten D. reticulatus (2.5%) ticks examined were found positive for DNA of B. canis canis originating from three out of eight collection sites. Consequently, an endemic distribution of D. reticulatus was confirmed and a natural  相似文献   

9.
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   

10.
Mortality rates and the prevalence of disease were assessed in 115 flocks of traditionally managed sheep and goats in two Divisions of the North West Province of Cameroon by means of a questionnaire to the owners. The mortality rate was significantly higher in sheep than in goats and also higher in young stock than in adults. Tethering the animals during the day resulted in significantly lower mortality in both adult and young sheep and also in kids. Disease problems of small ruminants, identified on the basis of signs reported by their owners, included intestinal parasitism, especially helminthiasis, tick infestation and associated diseases, pneumonia, goat plague (peste des petits ruminants) and Oestrus ovis infestation. Treatment of sick animals was only practised on a very small scale, often by possibly ineffective traditional methods. The owners identified tick infestation and diarrhoea as common causes of death. Recommendations are made on control measures suitable for application in this area.  相似文献   

11.
The infectivity rate of Babesia equi in the salivary glands of Hyalomma anatolicum anatolicum was assessed. The hungry nymphs were fed on a donkey experimentally infected with B. equi. The engorged dropped-off nymphs were collected at different levels of parasitaemia and kept in BOD incubator. After ecdysis, the hungry adults were prefed on rabbits for different time intervals, thereafter the salivary glands were dissected out and acini were examined after methyl green pyronin (MGP) staining. A total of 134 male and 139 female ticks were dissected out. Average infected acini per tick were found to be significantly higher (p<0.05) in male as compared to the female ticks. Further, maximum infected acini in both male and female ticks were found at 24h of prefeeding on rabbits and overall infected acini per tick increased with rise in parasitaemia. The release of infected ticks on susceptible donkeys resulted in development of clinical babesiosis.  相似文献   

12.
A shrubby plant, abundant in east Kenya, Gynandropsis gynandra (L.) Brig., was shown to exhibit repellent and acaricidal properties to larvae, nymphs and adult Rhipicephalus appendiculatus and Amblyomma variegatum ticks. All stages of ticks avoided the leaves of the plant and a high percentage of the ticks which were continuously exposed to its leaves died; surviving ticks were weak and inactive but regained activity when exposed to fresh air. The effectiveness of the plant's leaves as a repellent and acaricide was most pronounced on nymphs and least pronounced on adults. Field investigations indicated that ticks were not found up to 2-5 m from the plant in areas where the plant was predominant. The potential of using the plant for tick control within an integrated tick management system in the resource-poor farming context in Africa was highlighted.  相似文献   

13.
Suppose one of your clients from southern Florida starts talking about cattle egrets while you are vaccinating her cat. It seems she found a nearly dead egret near the cattle pen a few days ago, picked it up, and noticed a number of what looked like small ticks on the legs. Or, suppose you are called out to a small dairy in central Texas to look at some cows that are feverish and anemic. The first animal you examine has a few brown ticks attached just under the tail. Finally, perhaps you are looking at a lame tortoise for a reptile fancier, a new client, and find a large, colorful tick on a hind leg, well up under the shell. Ring any bells? Egrets are great hosts for the immature stages of Amblyomma ticks and have been captured and marked in the eastern Caribbean, then recaptured in the Florida Keys. Those cattle ticks in Texas might be acaricide-resistant Boophilus ticks that originated in Mexico. The Amblyomma tick on the tortoise could well have "hitch-hiked" all the way from South Africa. By now you remember that both Amblyomma and Boophilus ticks are efficient vectors of two tickborne diseases in this hemisphere, heartwater (in the case of Amblyomma) and babesiosis (transmitted by Boophilus ticks). Both of these diseases are exotic to the United States, and because our livestock are considered to be totally susceptible, an introduced infection could result in high initial death losses (approximately 70%); thus, both the ticks and the diseases pose immediate threats to the health and economic security of United States animal industries. Most importantly, you, whether as a small animal or large animal practitioner, are the first line of defense against such exotic diseases and their vectors.  相似文献   

14.
Recent outbreaks of bovine babesiosis caused by Babesia bovis in Swaziland had indicated the presence of the vector tick Boophilus microplus in the country although it had never before been directly identified. Engorged female Boophilus ticks were collected from cattle at diptanks in the course of a tick resistance survey and used to map the distribution of the two different species of Boophilus. B. decoloratus was found to be widespread throughout the country. B. microplus was identified for the first time in Swaziland and was found to have a patchy distribution. The implications of these findings are discussed.  相似文献   

15.
Yin H  Luo J  Guan G  Lu B  Ma M  Zhang Q  Lu W  Lu C  Ahmed J 《Veterinary parasitology》2002,108(1):21-30
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   

16.
A cross-sectional survey of ticks infesting sheep was conducted in Sennar State, Sudan. A total body collection of ticks was carried out at five localities Sennar town, Singa, Dinder, Abu Naama and Um Banein on two types of Desert sheep (Watish and Ashgar) on two farms at each locality at two monthly intervals for one year starting July 2002 to May 2003. Four tick genera and eight species were identified. They were Amblyomma lepidum, Hyalomma anatolicum anatolicum, Hyalomma truncatum, Rhipicephalus (Boophilus) decoloratus, Rhipicephalus camicasi, Rhipicephalus evertsi evertsi, Rhipicephalus guilhoni and Rhipicephalus muhsamae. A significant (P < or = 0.05) seasonal pattern of activity was observed for A. lepidum and R. guilhoni with peak activity occurring during rainy seasons. The highest mean number of ticks (7.26 +/- 0.58) was recorded at Abu Naama, while the lowest mean (3.61 +/- 0.31) was recorded in Sennar. Watish type sheep carried significantly (P < or = 0.05) more ticks than Ashgar type.  相似文献   

17.
A survey of ticks on cattle, camels, sheep, goats and donkeys in four different geographical locations of the Yemen Arab Republic (YAR) was carried out to provide more information on the possible risk of tick-borne diseases to imported exotic cattle included in the YAR's plans for livestock development. The most abundant ticks were Hyalomma spp. particularly on camels. Ticks found on cattle included Hyalomma spp., Amblyomma variegatum, Boophilus annulatus and Rhipicephalus spp. In general with the exception of camels tick burdens on all species of domestic livestock were very low. Two hundred and ninety eight serum samples from miscellaneous adult cattle throughout the country were negative to a test for Anaplasma marginale antibodies. It is speculated that tick burdens in the YAR are too low for significant disease transmission and the implications of the findings are discussed.  相似文献   

18.
SUMMARY Transmission of Babesia bovis by the tick Boophilus microplus was studied in 4 breeding herds of European and Zebu x European cattle under different levels of tick infestation. The observations consisted of weekly counts of female ticks on the cattle, monthly serological tests for antibodies to B. bovis, examination of tick larvae from the pasture to determine B. bovis infection rates and comparison of the suitability of paddocks for tick reproduction. The rate of transmission (inoculation rate) was estimated in terms of the daily probability of infection and consisted of the product of the mean daily tick infestation head-1 and the babesial infection rate in tick larvae. The theoretical value of the minimum inoculation rate required to produce stability of babesiosis is 0.01. This value was exceeded only in a herd of European cattle with minimal tick control and grazing on a pasture favourable for tick reproduction. Instability of babesiosis occurred in the other herds of European cattle after tick numbers had been reduced by pasture spelling and strategic dipping and after reduction in the babesial infection rate in ticks apparently caused by unfavourable environmental conditions. Over a period of years, the tick infection rates also declined as a consequence of the reduction in numbers of ticks. The Zebu x European cattle failed to generate inoculation rates greater than the minimum level, even though no tick control measures were applied. This was attributed to lower babesial infection rates in the ticks than those observed in a comparable herd of European cattle and to the high tick resistance of the Zebu crosses which maintained the tick populations at low levels. Both factors combined to produce a low inoculation rate.  相似文献   

19.
The epidemiology of Karoo paralysis, induced by the tick Ixodes rubicundus, was investigated in a paralysis-enzootic area of the southwestern Orange Free State, Republic of South Africa. Sheep became paralysed during the last week of April and the first week of May during the 1985 and 1986 seasons, respectively. Paralysis cases were recorded up until July, but most paralysis cases occurred during the first week of May with a second but smaller peak occurring during June. Tick numbers on paralysed sheep closely followed peak periods in paralysis. A total of 65 and 50% of the naive sheep became paralysed during the 1985 and 1986 seasons, respectively. The seasonal pattern of tick infestation by female I. rubicundus was similar on both previously exposed and on naive sheep. The results of this study indicate that a certain number of ticks per kilogram host body mass is required before symptoms of paresis of paralysis are observed. In general the tick burden per kilogram host mass was significantly greater in paralysed compared to non-paralysed sheep. The range in the number of ticks per kilogram host mass may, however, overlap between non-paralysed and paralysed groups. Previously exposed or previously paralysed sheep are less susceptible to paralysis in the following year. Differences in susceptibility between individual sheep seems likely.  相似文献   

20.
Four to 10 Dorper sheep on each of 12 farms in the Cape Province and 3 farms in the Orange Free State were examined for adult ixodid ticks at approximately 2- to 4-weekly intervals over periods varying from 4 to 18 months, commencing during January, February or April 1989. The farms in the Cape Province were located in the north-west, south-west and south of the province. Those in the Orange Free State were situated in the north-east and in the south. The sheep in the Cape Province harboured 10 species of ixodid ticks and the seasonal abundances of Ixodes rubicundus, Rhipicephalus evertsi evertsi, Rhipicephalus gertrudae and Hyalomma truncatum were determined. The animals in the Orange Free State were infested with 7 tick species and the seasonal abundances of I. rubicundus, R. evertsi and Hyalomma marginatum rufipes were determined.  相似文献   

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