Ticks and hemoparasitic diseases in cattle in Senegal. IV. The southern Sudan area

The authors report on the results of an investigation on ticks and hemoparasitoses of cattle, sheep and goats in the South Sudanian area of Senegal. Systematic routine dipping against ticks of cattle, 40 sheep and 40 goats was set during 15 months, with a view to determine the population dynamics together with an acurate localization of the different species concerned. The following parasites were collected from these ruminants: Amblyomma variegatum, Boophilus geigyi, Hyalomma truncatum, H. m. rufipes, Rhipicephalus lunulatus, Rh. sulcatus, Rh. e. evertsi, Rh. senegalensis. At the same time joint research was conducted on hemoparasitoses by mean of blood smears and of splenectomy. In cattle were found Theileria velifera, Th. mutans, Anaplasma marginale, Babesia bigemina, Ehrlichia bovis, and microfilaria of Setaria labiatopapillosa. Anaplasma ovis, Theileria ovis, Ehrlichia ovina, Trypanosoma vivax, T. congolense are involved in infections detected in goats and sheep. Among grown up and found apparently healthy animals, the hematocrite values have been studied as well as the seasonal variations of the haematological parameter.     

Babesia, Theileria and Anaplasma spp. infecting sable antelope, Hippotragus niger (Harris, 1838), in southern Africa

Some observations are recorded on blood parasites of sable antelopes. Blood smears of 124 of these antelopes from South Africa and Zimbabwe were examined and 7 were found to be positive for a Babesia sp., identified as Babesia irvinesmithi Martinaglia 1936. A total of 70 of the smears were positive for theilerial piroplasms, while 1 smear had macroschizonts (with cytomeres) and microschizonts of a Theileria (= Cytauxzoon) sp. One blood smear was positive for an Anaplasma sp. Attempts to isolate the Babesia sp. by subinoculating blood from sable to splenectomized and intact sable and splenectomized cattle were unsuccessful. Attempts to infect sable with Babesia bovis and Babesia bigemina were likewise unsuccessful. Theilerial piroplasms reached high levels in a splenectomized sable but could not be transmitted with blood to cattle. The Anaplasma sp. was found to be infective for sheep but not for cattle.     

Observed prevalence of tick-borne pathogens in domestic animals in Sicily, Italy during 2003-2005

The objective of this study was to characterize the observed prevalence of tick-borne pathogens (TBP) in domestic animals in Sicily, Italy during 2003-2005. Serological (competitive ELISA and indirect immunofluorescence antibody, n = 3299) and DNA tests (polymerase chain reaction and reverse line blot, n = 2565) were conducted on horse, donkey, cattle, sheep, goat, pig and dog samples. Pathogens analysed included Anaplasma, Ehrlichia, Rickettsia, Babesia and Theileria species, and Coxiella burnetii. The most prevalent TBP were Anaplasma and Babesia species. The results reported herein suggested that cattle could serve as the major reservoir for Babesia and Theileria spp. while for Anaplasma spp. cattle, dogs, sheep and goats may be the most important reservoir species. These results expanded our knowledge about the prevalence of TBP in Sicily and provided information to understand the epidemiology of tick-borne diseases and may help to implement measures to diagnose, treat and control transmission to humans and animals in this region.     

Detection and quantification of Anaplasma marginale DNA in blood samples of cattle by real-time PCR

A TaqMan-based real-time PCR assay was developed for the diagnosis of Anaplasma marginale infection of cattle. The established assay was proven to be highly specific, since no cross-reactions were observed with other Anaplasma species of ruminants, including the closely related Anaplasma centrale, or other haemoparasites of ruminants (Anaplasma bovis, Anaplasma ovis, Anaplasma phagocytophilum, Babesia bovis, Babesia bigemina, Theileria annulata and Theileria buffeli). The detection limit was equal to that of nested (n)PCR (10(1) copies of standard DNA and 3 x 10(1) infected erythrocytes ml(-1) of blood). The assay was also reproducible, as shown by satisfactory low intra-assay and inter-assay coefficients of variation. Fifty-four blood samples of ruminants (cattle, n = 51; sheep, n = 2; goats, n = 1), that had been tested previously by reverse line blot (RLB) hybridisation, were subjected to an nPCR assay and the newly established real-time PCR assay. By using real-time PCR, A. marginale DNA was detected in 39/51 bovine samples, with DNA titres ranging from 3.60 x 10(3) to 5.70 x 10(8) copies ml(-1) of blood, whereas sheep and goat samples tested negative. The concordance with nPCR was 100%, whereas a unique sample that had tested negative by RLB gave positive results by nPCR and real-time PCR. The established assay could overcome the limitations of existing diagnostic methods, allowing for simultaneous detection and quantification of the A. marginale DNA in bovine blood, that is essential to support the clinical diagnosis, to assess the carrier status of the animals and to evaluate the efficacy of vaccines and antirickettsial drugs.     

Haemoparasite prevalence and Theileria parva strain diversity in Cape buffalo (Syncerus caffer) in Uganda

Cape buffalo (Syncerus caffer) are considered to be an important reservoir for various tick-borne haemoparasites of veterinary importance. In this study we have compared the haemoparasite carrier prevalence in buffalo from four geographically isolated national parks in Uganda [Lake Mburo National Park (LMNP), Queen Elizabeth National Park (QENP), Murchison Falls National Park (MFNP) and Kidepo Valley National Park (KVNP)]. Differences were seen in haemoparasite prevalence in buffalo from the four national parks. All the buffalo sampled in LMNP were carriers of Theileria parva however, buffalo from MFNP and KVNP, which are both located in the north of Uganda, were negative for T. parva. Interestingly, 95% of buffalo in the northern part of QENP were T. parva positive, however all buffalo sampled in the south of the park were negative. A high multiplicity of infection was recorded in all the buffalo found to be carrying T. parva, with evidence of at least nine parasite genotypes in some animals. Most of the buffalo sampled in all four national parks were carriers of T. mutans and T. velifera, however none were carriers of T. taurotragi, Babesia bovis, Babesia bigemina, Ehrlichia bovis or Ehrlichia ruminantium. All the buffalo sampled from LMNP were positive for T. buffeli and T. sp. (buffalo) however, buffalo from the parks in the north of the country (KVNP and MFNP) were negative for these haemoparasites. Anaplasma centrale and Anaplasma marginale were circulating in buffalo from all four national parks. T. parva gene pools from two geographically separated populations of buffalo in two of the national parks in Uganda (LMNP and QENP) were compared. The T. parva populations in the two national parks were distinct, indicating that there was limited gene flow between the populations. The results presented highlight the complexity of tick-borne pathogen infections in buffalo and the significant role that buffalo may play as reservoir hosts for veterinary haemoparasites that have the potential to cause severe disease in domestic cattle.     

羊泰勒虫PCR检测方法的建立和初步应用

利用羊泰勒虫18SrRNA基因的序列特点,设计合成种特异性引物,建立羊泰勒虫PCR检测方法,该方法能特异性扩增398bp的羊泰勒虫18SrRNA基因片段,而对羊巴贝斯虫、羊无浆体、牛环形泰勒虫和牛伊氏锥虫的基因组DNA没有扩增带出现。对羊泰勒虫基因组DNA的最小检测量为0.12fgDNA。通过检测124份临床样品,24份为羊泰勒虫感染阳性,其余为阴性。结果表明,建立的PCR检测方法具有极高的敏感性和特异性,可用于羊泰勒虫病和临床健康带虫羊的诊断。     

Current status of bovine haemoparasitic diseases in Martinique (French West Indies)]

A serological survey using indirect immunofluorescence (IFAT) for bovine babesiosis (Babesia bovis and B. bigemina) and card test for anaplasmosis, indicates that these haemoparasites are widespread in Martinique. The high prevalences (62% for B. bovis, 52% for B. bigemina and 43% for Anaplasma marginale) lead to the hypothesis of an unstable epizootic situation for these three haemoparasitic diseases. However, the number of smears examined was too low to evaluate their clinical incidence. Both the American and Cuban card tests gave similar results in the detection of antibodies to A. marginale. Theileria mutans is described for the first time in Martinique. Trypanosomosis (Trypanosoma vivax) has disappeared from Martinique, on clinical and serological evidence.     

Bovine borreliosis in Botswana

Clinical Borrelia theileri infection was reported for the first time in cattle from Botswana concurrent with Babesia bovis and Theileria mutans infections. Two animals, an ox and a cow of the Tswana breed demonstrated clinical signs of fever, haemoglobinuria, inappetance, diarrhoea, pallor of mucous membranes, enlarged superficial lymph nodes and rough hair coats. Examination of the blood smears from the affected animals revealed numerous B. theileri, and very few B. bovis and T. mutans organisms. Oxytetracycline was administered parenterally to all the animals in the herd. The ox, being extremely weak and recumbent for the previous 4-5 days, succumbed to death the day after the examination. The clearance of spirochaetes from the blood circulation and recovery of the cow three days after treatment with oxytetracycline suggest an involvement of B. theileri in producing clinical disease.     

Ticks and hemoparasitoses of livestock in Senegal. III. The Northern Sudan area

The authors describe the results of a study on ticks and hemoparasitoses of cattle and small ruminants in the Senegalese north-sudanian area. For 15 months, 40 bovine, 40 sheep and 40 goats received a routine dipping treatment, aimed at the determination of the tick population dynamics together with an accurate localization of the preferential sites for the different species. The following parasites were collected from the animals: Hyalomma marginatum rufipes, H. truncatum, Rhipicephalus lunulatus, Rh. e. evertsi, Rh. sulcatus, Rh. senegalensis, Boophilus decoloratus. Joint studies were conducted on the hemoparasites using blood smear and splenectomy. Among bovine, Anaplasma marginale, Ehrlichia bovis, Theileria mutans, Th. velifera, Trypanosoma congolense, T. brucei and microfilariae from Setaria labiatopapillosa were observed. Babesia bigemina was observed after a splenectomy. In small ruminants, the detected infections are brought about by A. ovis, Th. ovis and T. vivax. Hematocrite value of apparently healthy animals are studied as well as the seasonal variation of this hematological factor.     

Detection of haemoparasites in cattle by reverse line blot hybridisation with a note on the distribution of ticks in Sicily

A reverse line blot hybridisation (RLB) of 21 oligonucleotides with polymerase chain reaction (PCR) amplified regions of 16S rRNA (Ehrlichia/Anaplasma group) or 18S rRNA (Babesia/Theileria group) genes of haemoparasites detected Theileria annulata, T. buffeli/orientalis, Babesia bovis, B. bigemina, B. divergens, Ehrlichia bovis, Anaplasma marginale, A. centrale and unknown species within the Rickettsia tribe.A very high prevalence of mixed infections was detected, which indicated that animals infected with Babesia spp. were also infected with Theileria spp. and/or Anaplasma spp.The tick distribution appeared to be seasonal with Hyalomma marginatum as the most frequently observed tick and Boophilus annulatus and Ixodes ricinus as the least frequently observed ticks. Other species identified in the 818 ticks collected during the five sampling periods between April 1998 and November 1999 included H. lusitanicum, Rhipicephalus sanguineus group, R. bursa, Dermacentor marginatus, Haemaphysalis punctata, B. annulatus and I. ricinus.     

甘肃省牛蜱传性血液原虫生物学特性研究及病原的分离

用病原检查法对甘肃省４２个县市的１３１１头牛进行了牛蜱传性血液原虫病的大面积调查,证实该省牛蜱传染性血液原虫的种类为双芽巴贝斯虫,大巴贝斯虫,瑟氏泰勒虫,环形泰勒虫及国边虫等５种病原,     

Comparison of blood smear and indirect fluorescent antibody techniques in detection of haemoparasite infections in trade cattle in Nigeria

The incidence of blood parasites in trade cattle was surveyed with emphasis on tick-borne parasites, using blood smears and immunofluorescent antibody (IFA) techniques. With the blood smear method, about 9 and 8.9% of cattle examined were found positive for Babesia bigemina and Anaplasma marginale, respectively. Percentage infections with other parasites were 3.33, 1.92, 0.75, 0.75 and 0.58, respectively, for Babesia bovis, Trypanosoma brucei, Anaplasma centrale, Eperythrozoon and Theileria species as well as Trypanosoma congolense. The incidence of A. marginale infection was at its peak during the rainy season while B. bigemina was most prevalent during the dry season. There were mixed infections of Anaplasma and Babesia (1.42%); Babesia and trypanosomes (1.00%); Babesia and Eperythrozoon (0.75%) and Babesia and Theileria (0.75%). Using the indirect fluorescent antibody test, 93, 55 and 68% of cattle sera examined were found to be positive for B. bigemina, B. bovis and A. marginale, respectively. Forty-nine percent of the positive sera of B. bigemina had highest titres. The importance of using serological means for determining the endemic levels of tick-borne diseases in cattle in Nigeria is discussed.     

Bovine piroplasms in Minorca (Balearic Islands, Spain): a comparison of PCR-based and light microscopy detection

The present study provides the first epidemiological data regarding infection by Theileria and Babesia piroplasms in cattle in Minorca. More than 94% of the studied animals were positive for the presence of Theileria sp., and of those, 41.3% were positive for the presence of Theileria annulata. These results indicate that the prevalence of Mediterranean theileriosis caused by T. annulata is very high in Minorcan dairy farms and that other Theileria sp. are also present in the area. The prevalence of infection was similar throughout the study indicating an endemic situation in this island. The use of PCR resulted in significantly higher efficacy of detection of Theileria sp. compared to microscopical observation (MO) of blood smears and allowed the specific discrimination between pathogenic and non-pathogenic theilerias which cannot be accomplished by traditional diagnosis by MO. Babesia infection in the area was mainly due to Babesia bigemina (6.0% of the studied animals were infected), while one animal (0.75%) was found to be infected by Babesia bovis. It was observed that 31% of animals infected with B. bigemina had a concurrent infection of T. annulata. PCR also resulted in a significantly higher efficacy of detection of Babesia sp. compared to MO when infection levels were higher, towards the end of the study period. The results clearly demonstrate that parasitic infection by piroplasms, especially Theileria sp. is common and endemic in the island of Minorca and that PCR is the optimal approach for the detection and discrimination of these important parasites.     

Ehrlichia ruminantium seroprevalence in domestic ruminants in Ghana. II. Point prevalence survey

Serum samples collected on a single occasion from cattle, sheep and goats at sites in all 10 regions of Ghana were tested for antibodies to Ehrlichia (previously Cowdria) ruminantium, the causative agent of heartwater, by polyclonal competitive ELISA (PC-ELISA). The survey revealed the presence of heartwater-exposed ruminants throughout the country, with local seroprevalence up to 100%. Seronegative, and therefore presumably susceptible, animals were also present in all regions, in some areas in numbers high enough to indicate local endemic instability. Overall seroprevalences in cattle, sheep and goats were 61, 51 and 28% respectively, and were generally higher in the northern part of the country and lower in the forest zone. Amongst animals over 1 year old, two thirds of cattle and sheep, and around one third of goats throughout the country had been exposed to E. ruminantium. In the north, seroprevalence in sheep sampled with and without cattle was similar, whereas in the south seroconversion rates in sheep were significantly higher in areas where cattle were present.     

Detection of Theileria and Babesia species in ticks collected from cattle

The present study was carried out to detect tick species that infest cattle, and Theileria and Babesia species transmitted by these ticks in Kayseri province (Turkey). A total of 300 cattle were examined for tick infestations. Of the 300 cattle, 117 (39%) were infested with ticks. A total of 1160 ticks belonging to 11 Ixodid genera were collected from the infested animals and their shelters. The most prevalent tick species was Boophilus annulatus 26.37% (306/1160) followed by Hyalomma marginatum marginatum 21.12% (245/1160) and Rhipicephalus turanicus 18.7% (217/1160). The collected ticks were separated into 43 tick pools, according to their species. These pools were examined for bovine Theileria and Babesia species (Theileria sp., Babesia sp., Theileria annulata, T. buffeli/orientalis, Babesia bigemina, B. bovis and B. divergens) by using the reverse line blotting method (RLB). Of the 43 tick pools examined, 6 (14%) were infected with B. bigemina, 4 (9.3%) with T. annulata, and 1 (2.3%) with Babesia sp., whereas 1 (2.3%) displayed mixed infection with T. annulata + B. bigemina. The sequence and phylogenetic analyses of Babesia sp., which could not be identified to the species level by RLB, were performed. In the phylogenetic tree, Babesia sp. (Kayseri 1) grouped with Babesia sp. (Kashi 2), Babesia sp. (Kashi 1), Babesia sp. (Xinjiang) and B. orientalis with 96.8-100% identity.     

Development of a polymerase chain reaction method for diagnosis of Babesia ovis infection in sheep and goats

In this study, a pair of oligonucleotide primers were designed according to the nucleotide sequence of the small subunit ribosomal RNA (ssu rRNA) gene of Babesia ovis isolated from sheep in eastern Turkey. The primers were used to detect parasite DNA from blood samples of B. ovis-infected sheep and goats by polymerase chain reaction (PCR). A 549-bp DNA fragment was specifically amplified from blood samples from sheep and goats, naturally infected with B. ovis. No PCR products resulted from Babesia motasi, T. ovis, Theileria sp. OT1, Theileria sp. OT3, T. lestoquardi, B. canis, B. microti,T. annulata or normal sheep leucocytes DNA using these specific primers. B. ovis-infected erythrocytes with 1% parasitemia were subjected to 10-fold serial dilutions (from 10(-1) to 10(-9)) using an uninfected sheep erythrocytes, and DNA was extracted from each diluted sample for testing the sensitivity of the PCR. The PCR was sensitive enough to detect parasite DNA from the dilution of 10(-5) with 0.00001% parasitemia. This is more sensitive than examining 200 fields under light microscopy. In addition, 98 field samples collected from small ruminanats in eastern Turkey were tested for B. ovis infection. Four samples were positive Babesia spp. in blood smears, 21 samples were positive for B. ovis DNA by PCR. These results indicate that the PCR provides a useful diagnostic tool for the detection of B. ovis infection in sheep and goats.     

Detection of Theileria and Babesia in brown brocket deer (Mazama gouazoubira) and marsh deer (Blastocerus dichotomus) in the State of Minas Gerais, Brazil

Intraerythrocytic protozoan species of the genera Theileria and Babesia are known to infect both wild and domestic animals, and both are transmitted by hard-ticks of the family Ixodidae. The prevalences of hemoprotozoa and ectoparasites in 15 free-living Mazama gouazoubira, two captive M. gouazoubira and four captive Blastocerus dichotomus from the State of Minas Gerais, Brazil, have been determined through the examination of blood smears and the use of nested polymerase chain reaction (nPCR). The cervid population was inspected for the presence of ticks and any specimens encountered were identified alive under the stereomicroscope. Blood samples were collected from all 21 animals, following which blood smears were prepared, subjected to quick Romanowsky staining and examined under the optical microscope. DNA was extracted with the aid of commercial kits from cervid blood samples and from tick salivary glands. The nPCR assay comprised two amplification reactions: the first was conducted using primers specific for a 1700 bp segment of the 18S rRNA gene of Babesia and Theileria species, whilst the second employed primers designed to amplify a common 420 bp Babesia 18S rRNA fragment identified by aligning sequences from Babesia spp. available at GenBank. The ticks Amblyomma cajennense, Rhipicephalus microplus and Dermacentor nitens were identified in various of the cervids examined. Of the animals investigated, 71.4% (15/21) were infected with hemoprotozoa, including Theileria cervi (47.6%), Theileria sp. (14.3%), Babesia bovis (4.8%) and Babesia bigemina (4.8%). However, only one of the infected wild cervids exhibited accentuated anaemia (PCV=17%). This is first report concerning the occurrence of Theileria spp. in Brazilian cervids.     

Tick-borne blood parasites in nyala (Tragelaphus angasii, Gray 1849) from KwaZulu-Natal, South Africa

A total of 97 blood samples of nyala (Tragelaphus angasii, Gray 1849) from South Africa were tested for the presence of tick-borne haemoparasites by means of polymerase chain reaction (PCR) and reverse line blot (RLB) hybridization. The majority of blood samples contained several different haemoparasites, often in combination. Prevalent haemoparasites were Theileria sp. (kudu), T. buffeli, Theileria sp. (sable), T. bicornis, Ehrlichia sp. Omatjenne, Anaplasma marginale and A. bovis. This serves as the first report of Theileria sp. (kudu), T. buffeli, T. bicornis, Ehrlichia sp. Omatjenne, A. marginale and A. bovis in nyala, who seem to carry multiple haemoparasites without ill effect.     

Seroprevalences of vector-transmitted infections of small-holder dairy cattle in coastal Kenya

A cross-sectional study was carried out from July to September 1989 in Kaloleni Division, Coast Province, Kenya to estimate the prevalence of vector-transmitted diseases in small-holder dairy cattle and to identify the risk factors associated with different management systems. One hundred and thirty of the 157 herds with dairy cattle in Kaloleni Division were surveyed. These were from three agro-ecological zones (coconut-cassava, cashew nut-cassava and livestock-millet), comprised two management systems (stall-feeding and herded grazing) and were herds with either dairy cattle only or with Zebu and dairy cattle. A formal questionnaire sought answers to questions on cattle health and management practices. A total of 734 dairy and 205 Zebu cattle in 78 dairy and 52 mixed (dairy and Zebu) herds were sampled and screened for haemoparasites (Trypanosoma, Anaplasma, Babesia, and Theileria infections). Sera were tested for antibodies to Theileria parva, using the schizonts-antigen indirect fluorescent-antibody (IFA) test and to antibodies for Babesia bigemina and antigens to Anaplasma marginale by enzyme-linked immunosorbent assay (ELISA). Packed-cell volume (PCV) also was measured. Tick-control measures were practised by all except three of the farmers. Despite this, overall seroprevalence to T. parva was >70%--suggesting either that control practices were not strictly implemented or they were ineffective. The seroprevalence of T. parva in adult cattle kept in stall-feeding systems in the coconut-cassava zone was significantly lower (57+/-8% (S.E.)) than in herded-grazing systems (79+/-3%) and there was no association between antibody prevalence and age of cattle in this zone. Antibody prevalences in cattle in the cashew nut-cassava and the drier livestock-millet zone increased with age. Cattle in herded-grazing systems had an overall lower seroprevalence of T. parva infection in the livestock-millet zone (45+/-6%) than in the other two zones.Analysis was confined to the coconut-cassava zone for B. bigemina and to the coconut-cassava and cashew nut-cassava zones for A. marginale. Mean prevalences of B. bigemina were 40.9+/-9 and 73+/-6% for dairy cattle under stall-feeding and herded-grazing systems, respectively, and increased with age. Antigen prevalences of A. marginale were over 80% in all age groups of cattle in the coconut-cassava and cashew nut-cassava zones. Overall trypanosome prevalence in cattle was <1%. Trypanocidal treatment was uncommon. The variations in antibody prevalence associated with risk factors such as feeding system, agro-ecological zone and age of animal suggest that management system influenced exposure to tick-borne infection (particularly, T. parva infections) in small-holder dairy cattle in coastal Kenya.     

Observations on blood-borne parasites of domestic livestock in the Lower Juba Region of Somalia

The commonest parasite to be found in blood of cattle in the Lower Juba Region is Theileria mutans. Antibodies against Trypanosoma spp. and Anaplasma marginale could be detected serologically whereas no antibodies against T. parva and T. annulata were present. A list of ticks collected between 1980 and 1982 in the above mentioned area shows that vectors of T. mutans are common. As the cattle throughout the region are indigenous Somali Boran it seems that endemic stability is maintained and mortality from T. mutans infection is negligible. It is not yet clear whether pathogenic strains of T. mutans similar to those isolated in East Africa occur.