Babesia Bigemina Research Articles

Molecular detection and characterization of Babesia bovis, Babesia bigemina, Theileria species and Anaplasma marginale isolated from cattle in Kenya.

BackgroundInfections with Babesia bovis, Babesia bigemina, Theileria species and Anaplasma marginale are endemic in Kenya yet there is a lack of adequate information on their genotypes. This study established the genetic diversities of the above tick-borne hemoparasites infecting cattle in Kenya.MethodsNested PCR and sequencing were used to determine the prevalence and genetic diversity of the above parasites in 192 cattle blood samples collected from Ngong and Machakos farms. B. bovis spherical body protein 4, B. bigemina rhoptry-associated protein 1a, A. marginale major surface protein 5, Theileria spp. 18S rRNA, T. parva p104 and T. orientalis major piroplasm surface protein were used as the marker genes.ResultsB. bovis, B. bigemina, T. parva, T. velifera, T. taurotragi, T. mutans and A. marginale were prevalent in both farms, whereas T. ovis, Theileria sp. (buffalo) and T. orientalis were found only in Ngong farm. Co-infections were observed in more than 50 % of positive samples in both farms. Babesia parasites and A. marginale sequences were highly conserved while T. parva and T. orientalis were polymorphic. Cattle-derived T. parva was detected in Machakos farm. However, cattle and buffalo–derived Theileria were detected in Ngong farm suggesting interactions between cattle and wild buffaloes. Generally, the pathogens detected in Kenya were genetically related to the other African isolates but different from the isolates in other continents.ConclusionsThe current findings reaffirm the endemicity and co-infection of cattle with tick-borne hemoparasites, and the role of wildlife in pathogens transmission and population genetics in Kenya.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-1106-9) contains supplementary material, which is available to authorized users.

Identification of a vertically transmitted strain from Anaplasma marginale (UFMG3): Molecular and phylogenetic characterization, and evaluation of virulence

Bovine anaplasmosis is a disease caused by the intraerythrocytic rickettsia species Anaplasma marginale and results in great economic losses in tropical and subtropical regions. Vertical transmission is an important phenomenon that contributes to the persistence of different strains of the agent within the same herd. The identification of new strains and genetic characterization studies are essential to understanding their epidemiology and virulence and for vaccine development. The aim of this study was to perform molecular and phylogenetic characterizations of a new vertically transmitted strain from A. marginale and to evaluate its virulence by experimental inoculation of rickettsia-free calves. Thirty newborn Holstein calves were subjected to molecular tests for the detection of A. marginale, Babesia bovis and Babesia bigemina. Calves positive for A. marginale (n=3) were splenectomized and monitored for the clinical manifestations of anaplasmosis. Blood samples from one of the calves that presented rickettsemia of 42.8% and spontaneous recovery of clinical parameters were used for molecular and phylogenetic characterization (msp1a gene), and inoculum production was used for the evaluation of virulence. This strain was identified as UFMG3. Three tandem repeat forms (13 and MGI19) were identified from the analysis of the msp1a gene, in which the form MGI19 appeared twice. Analysis of these repeats revealed the presence of the sequences QASTSS and SSASGQQQESS and of aspartic acid (D) at position 20 of both repeats. Phylogenetic analysis showed a close relationship among the UFMG3, MGI19 and UFMG2 strains. For virulence evaluation, six Holstein calves were inoculated intravenously with 2×107A. marginale UFMG3-infected erythrocytes. The calves showed maximum rickettsemia of 5.1%, a moderate decrease in packed cell volume and spontaneous recovery of clinical parameters without the need for treatment. The results of experimental inoculation suggest that the strain A. marginale UFMG3 has low virulence and potential application for use as a live vaccine against A. marginale.

Molecular and Parasitological Survey of Bovine Piroplasms in the Black Sea Region, Including the First Report of Babesiosis Associated with Babesia divergens in Turkey.

Clinical cases of babesiosis were evaluated, and the frequency of bovine Babesia and Theileria parasites was determined in cattle. Blood samples and thin blood smears were collected from 23 cattle exhibiting clinical signs of babesiosis. In addition, tick and blood samples were collected from 100 apparently healthy cattle cograzing from the same area. Egg masses obtained from fully engorged female ticks were included. DNA isolated from blood and tick samples was screened for Babesia and Theileria by reverse line blot assay. Piroplasms compatible with Babesia spp. were observed microscopically for symptomatic cattle as circular, oval, elongated, or pear-shaped bodies. Parasitemia ranged from 0.08 to 0.9% for Babesia bovis, 2.5 to 15.4% for Babesia bigemina, and 7.4% for Babesia divergens. Reverse line blot showed positivity in 13 (13%) of the sampled clinically normal cattle and revealed the presence of three Babesia species. Babesia bovis was the most prevalent (9/100, 9%), followed by Babesia occultans (3/100, 3%) and B. bigemina (1/100, 1%). One animal infected with B. bigemina was also infected with B. bovis. The single animal infected with B. divergens showed symptoms of babesiosis. Ticks were identified as Rhipicephalus annulatus, Rhipicephalus turanicus, and Ixodes ricinus. One female R. annulatus and its egg mass were infected with B. bigemina. Neither Theileria annulata nor Theileria buffeli/orientalis infections were observed in cattle or ticks. This is the first report of clinical babesiosis caused by B. divergens in cattle from Turkey.

In vitro cultivation and cryopreservation of Babesia bigemina sporokinetes in hemocytes of Rhipicephalus microplus

Cultures of tick hemocytes represent alternative cell lines for the isolation and cultivation of a variety of hemoparasites. The present study reports the development and evaluation of methods for the in vitro culture and maintenance of sporokinetes of Babesia bigemina in association with hemocytes of the tick Rhipicephalus microplus. Hemolymph, from engorged females infected with B. bigemina sporokinetes, was incubated at 28°C in L15 culture medium supplemented with 40% fetal bovine serum. Adherence of hemocytes to flask surfaces and the development of B. bigemina sporokinetes commenced on the first day of cultivation. The protozoa demonstrated clear motility and the capacity to adhere to hemocyte membranes for up to 25 days, at which time the hemocytes began to show signs of degeneration. Examination of Giemsa stained hemocyte cultures, revealed the presence of pyriformis forms, as well as mature and immature sporokinetes with dark red nuclei, centralized or near the apical extremities. Sporokinetes harvested from culture supernatants were cryopreserved in liquid nitrogen. Inoculation of parasite-free hemocyte cultures with defrosted sporokinetes, demonstrated the viability and interaction of the protozoa with the hemocytes over 21 days. Cultured hemocytes of R. microplus hold potential for development as a tool in the study of host parasite interactions and as a substrate for the in vitro maintenance of B. bigemina sporokinetes.

Tick-borne agents in domesticated and stray cats from the city of Campo Grande, state of Mato Grosso do Sul, midwestern Brazil

Anaplasmataceae agents, piroplasmids and Hepatozoon spp. have emerged as important pathogens among domestic and wild felines. The present work aimed to detect the presence of species belonging to the Anaplasmataceae family, piroplasmas and Hepatozoon spp. DNA in blood samples of domesticated and stray cats in the city of Campo Grande, state of Mato Grosso do Sul, midwestern Brazil. Between January and April 2013, whole blood samples were collected from 151 cats (54 males, 95 females and two without gender registration) in the city of Campo Grande, state of Mato Grosso do Sul, Brazil. DNA extracted from cat blood samples was submitted to conventional PCR assays for Theileria/Babesia/Cytauxzoon spp. (18S rRNA, ITS-1), Ehrlichia spp. (16S rRNA, dsb, groESL), Anaplasma spp. (16S rRNA, groESL) and Hepatozoon spp. (18S rRNA) followed by phylogenetic reconstructions. Out of 151 sampled cats, 13 (8.5%) were positive for Ehrlichia spp. closely related to Ehrlichia canis, 1 (0.66%) for Hepatozoon spp. closely related to Hepatozoon americanum and Hepatozoon spp. isolate from a wild felid, 1 (0.66%) for Cytauxzoon sp. closely related do Cytauxzoon felis, and 18 (11.9%) for Babesia/Theileria (one sequence was closely related to Babesia bigemina, eight for Babesia vogeli, five to Theileria spp. from ruminants [Theileria ovis, Theileria lestoquardi] and four to Theileria sp. recently detected in a cat). The present study showed that Ehrlichia spp., piroplasmids (B. vogeli, Theileria spp. and Cytauxzoon spp.) and, more rarely, Hepatozoon spp. circulate among stray and domesticated cats in the city of Campo Grande, state of Mato Grosso do Sul, midwestern Brazil.

Molecular characterization of the Israeli B. bigemina vaccine strain and field isolates

The present study demonstrated the genetic character of the Israeli Babesia bigemina vaccine strain and field isolates, based on rap-1a and rap-1c gene sequences. The RAP-1a of blood-derived Israeli B. bigemina field isolates shared 100% amino acid sequence identity. However, comparison of RAP-1c from various Israeli B. bigemina field isolates revealed that the total sequence identity among the field isolates ranged from 98.2 to 100%. High identity was observed when RAP-1a sequences from the Israeli vaccine strain and field isolates were compared with RAP-1a from Egypt, Syria, Mexico and South Africa, while, the Israeli RAP-1c sequences showed the highest identity to the Mexican isolate JG-29 and to the PR isolate from Puerto-Rico. Based on sequence variations between the rap-1a of the vaccine strain and that of the field isolate, and between the rap-1c of the vaccine strain and that of the field isolates, nPCR-RFLP procedures were developed that enable, for the first time differentiation between the Israeli B. bigemina vaccine strain and field-infection isolates. These assays could serve as fast and sensitive methods for detection and differentiation between Israeli B. bigemina vaccine strains and field isolates, as well as for epidemiological investigations.

BmVDAC upregulation in the midgut of Rhipicephalus microplus, during infection with Babesia bigemina

The molecular mechanisms involved during the infection of Rhipicephalus microplus midgut cells by Babesia bigemina are of great relevance and currently unknown. In a previous study, we found a voltage-dependent anion channel (VDAC)-like protein (BmVDAC) that may participate during parasite invasion of midgut cells. In this work, we investigated BmVDAC expression at both mRNA and protein levels and examined BmVDAC localization in midgut cells of ticks infected with B. bigemina at different times post-repletion. Based on the RT-PCR results, Bmvdac expression levels were significantly higher in infected ticks compared to uninfected ones, reaching their highest values at 24h post-repletion (p<0.0001). Similar results were obtained at the protein level (p<0.0001). Interestingly, BmVDAC immunolocalization showed that there was an important differential expression and redistribution of BmVDAC protein between the midgut cells of infected and uninfected ticks, which was more evident 24h post-repletion of infected ticks. This is the first report of BmVDAC upregulation and immunolocalization in R. microplus midgut cells during B. bigemina infection. Further studies regarding the function of BmVDAC during the infection may provide new insights into the molecular mechanisms between B. bigemina and its tick vector and could result in its use as an anti-tick and transmission-blocking vaccine candidate.

Molecular epidemiological survey and genetic analysis of vector-borne infections of cattle in Luzon Island, the Philippines

In the Philippines, vector-borne disease is one of the important problems in the livestock industry. To elucidate the epidemiology of vector-borne diseases in cattle on Luzon Island, the Philippines, the prevalence of five protozoan agents was assessed by polymerase chain reaction. Out of the 339 samples, 324 (95.5%), 154 (45.4%), 209 (61.6%), 140 (41.3%), and 2 (0.6%) were positive for Anaplasma marginale, Babesia bigemina, Babesia bovis, Theileria spp., and Trypanosoma evansi infections, respectively. Mixed infections were detected in 290 (85.5%) samples, of which 115 (33.9%) had two pathogens, 144 (42.5%) had three pathogens, and 31 (9.1%) had four kinds of pathogens. 16S rRNA gene was 100% identical in A. marginale compared with the same lineage across the world. B. bovis RAP-1 and B. bigemina AMA-1 genes were identical with 92.27%–100% and 97.07%–100% sequences, respectively, in the database (Asian isolates). MPSP genes of Theileria spp. were 83.51%–100% identical with the one another. Phylogenetic analysis showed that they belong to the groups of T. sergenti and T. buffeli. Positive rates of the tick-borne pathogens were extremely high in this area. These findings provide vital information that can be used for the planning and execution of effective control measures for vector-borne diseases in the Philippine cattle industry.

Seroprevalence of Babesiosis and Anaplasmosis in Apparently Healthy Large Ruminants of Punjab, India

Bovine babesiosis and anaplasmosis are two important enzootic, tick-borne diseases of cattle in India. The present study reports the seroprevalence of Babesia bigemina and Anaplasma marginale infection in bovines from different district of Punjab, India. A total of 184 serum samples from six districts of Punjab were evaluated for the presence of antibodies to both the parasitic antigens using a commercially available enzyme linked immunosorbent assay kit. The overall seroprevalence of B. bigemina and A. marginale was 30.9 and 20.6 % respectively, out of which cattle (46 and 31.3 %) showed more prevalence than the buffaloes (5.8 and 2.9 %). A co-infection percentage of 14.1 (24 cattle and 2 buffaloes) were also observed. These results may serve as a support either in prevention or control of the diseases.

Seasonal incidence of parasitic diseases in bovines of south western Gujarat (Junagadh), India.

The current study was conducted to investigate the incidence of parasitic diseases in bovines which were sick and brought at veterinary hospital for treatment. A total of 366 samples were investigated from cattle (n=175) and buffaloes (n=191) presented at Teaching Veterinary Clinical Complex (TVCC), Veterinary College, Junagadh, Gujarat during January to December 2014. Examination of Giemsa-stained peripheral blood smears exhibited that 58.6% of cattle and 41.2% of buffaloes were infected with haemoparasites comprising Babesia bigemina, Theileria annulata, and Anaplasma marginale @ of 54.0, 3.4 and 1.1 in cattle and 38.8, 1.2 and 1.2 percent in buffaloes, respectively. The incidence of total haemoparasites and B. bigemina infections was significantly higher (p<0.05) in cattle whereas, incidence of haemoparasites were recorded significantly higher in the month of July to November (i.e., rainy and autumn) in both cattle and buffaloes, respectively (p<0.01 and p<0.001). Coprological examination revealed that the overall incidence of gastrointestinal (GI) parasitic infection was 45.5% in cattle and 43.4% in buffaloes. The incidence of individual parasite was 11.4, 1.1, 2.3, 4.5, 1.1, 3.4, 2.3 and 19.3 in cattle and 4.7, 0.9, 0.0, 2.8, 0.9, 5.7, 0.0 and 28.3% in buffaloes for Eimeria spp., Trichuris spp., Toxocara vitulorum, Strongyle, Fasciola spp., amphistomes, Schistosoma indicum and Buxtonella sulcata, respectively which differ insignificantly (p>0.05). Seasonal prevalence of GI parasites was highest in summer in both cattle and buffaloes, the data being statistically non-significant (p>0.05). However, the incidence of B. sulcata in both cattle (19.3%) and buffaloes (28.3%) was higher in comparisons to other GI parasites. The present investigation emphasized that B. bigemina and B. sulcata are the most important parasites of bovines of this region.

Co-immunization of cattle with a vaccine against babesiosis and Lactobacillus casei increases specific IgG1 levels to Babesia bovis and B. bigemina

The effect of Lactobacillus casei administered along with a live attenuated vaccine vs. bovine babesiosis (VAC) on induction of IgG1 and IgG2 antibodies to Babesia bovis and Babesia bigemina was assessed by the indirect fluorescent antibody test (IFAT) in bovines of an endemic babesiosis area before (day 0) and after vaccination (days 15 and 30). We previously reported that L. casei increases the efficiency of VAC under controlled conditions and under extreme conditions in the field; however, the levels of IgG1 and IgG2 antibodies to B. bovis and B. bigemina are not known in vaccinated animals. Twenty-one dairy cows were allocated into three groups (seven animals per group): unvaccinated, vaccinated with VAC and vaccinated simultaneously with VAC and L. casei (VAC–LC). All animals were kept in a babesiosis endemic area at Tlalixcoyan, Veracruz. At days 15 and 30 after vaccination, the average levels of IgG1 to B. bovis and to B. bigemina were significantly higher in VAC–LC group than levels observed in VAC and control groups (P<0.01). Levels of IgG2 were similar in VAC and VAC–LC groups but higher than in the control group (P<0.01). When tested in in vitro cultures of B. bovis, sera from VAC–LC group significantly inhibited parasite growth as compared with the sera of the other two groups. It is suggested that the efficiency improvement of VAC, in part, is due to the L. casei boost of IgG1 over IgG2 antibodies to B. bovis and B. bigemina when the bacteria is co-inoculated with this vaccine.

First report of Babesia bigemina infection in white yaks in China

White yaks, a unique yak breed and the pearl of the plateau, only live in Tianzhu Tibetan Autonomous County (TTAC), Gansu Province, northwest China, contributing significantly to local economy. However, there was no information on the prevalence of Babesia bigemina in white yaks. In this study, a total of 974 serum samples collected from white yaks in TTAC were examined for specific antibodies against B. bigemina using a commercially available ELISA kit. The overall seroprevalence of B. bigemina in white yaks was 17.76% (173/974). A multivariate logistic regression analysis was performed to determine the risk factors associated with B. bigemina seroprevalence, and the results indicated that age, gender and the numbers of pregnancies of white yaks were not the significant risk factors. However, the white yaks in spring (OR=3.523, 95% CI=1.899–6.538, P<0.001) and summer (OR=3.439, 95% CI=1.909–6.193, P<0.001) encountered higher risk of being exposed to B. bigemina than that in winter. Thus, season was considered as a risk factor associated with B. bigemina infection. This is the first survey of B. bigemina seroprevalence in white yaks in China, which extends the host range for B. bigemina and provides useful information for controlling B. bigemina infection in white yaks.

Detection of Babesia bigemina infection in cattle from north-eastern India by polymerase chain reaction and its genetic relatedness with other isolates.

A total of 333 blood samples were collected from cattle suspected for haemoprotozoan infections from three states of north-eastern part of India. All the samples were examined for diagnosis of Babesia bigemina infection using PCR for detection of specific DNA. Out of these, 12 (3.60%) samples were found positive for B. bigemina DNA on PCR using the organism-specific primers derived from 18S ribosomal RNA (rRNA) gene of B. bigemina. An expected size of 1124-bp PCR product was visualized on agarose gel electrophoresis with all the 12 samples, and four of the products was further cloned and sequenced. Basic Local Alignment Search Tool (BLAST) analysis of B. bigemina sequences generated in the present study share 99.2 to 99.7% identity at 18S rRNA gene nucleotide sequence level. These Indian B. bigemina sequences were found to be closely related with the cognate gene nucleotide sequences of B. bigemina from Argentina and Kenya where 99.1 to 99.9% and 99.0 to 99.7% nucleotide identities were observed, respectively. Distant relationship of these Indian organisms was observed with few cognate gene sequences from China where more than 7% divergence was observed in the distance matrix.

Molecular prevalence ofBabesia bigeminainfection in cattle in western semi-arid and foothill regions of Punjab (India)

A nested PCR based prevalence study was done from June, 2011 to May, 2013 to determine the carrier status of Babesia bigemina infection in apparently healthy crossbred cattle from Western semi-arid and Foothill regions of Punjab (India). Of the 278 blood samples collected, an amplicon of 170 bp size was detected in 16.19% animals by nested PCR aa compared to the routine blood smear examination which showed parasitic piroplasms in only 1.80% samples. Regarding various risk factors, statistically nonsignificant variation was observed with respect to zone-wise, sex-wise and age-wise prevalence whereas season-wise disease prevalence showed significant variation (p<0.05).

Bovines immunized with Babesia bigemina surface-exposed peptides containing conserved B-cell epitopes elicit an improved Th1 response when supplemented with live, probiotic yeasts.

Bovines immunized with Babesia bigemina surface-exposed peptides containing conserved B-cell epitopes elicit an improved Th1 response when supplemented with live, probiotic yeasts.

Molecular biological identification of Babesia, Theileria, and Anaplasma species in cattle in Egypt using PCR assays, gene sequence analysis and a novel DNA microarray

In this preliminary study, a novel DNA microarray system was tested for the diagnosis of bovine piroplasmosis and anaplasmosis in comparison with microscopy and PCR assay results. In the Dakahlia Governorate, Egypt, 164 cattle were investigated for the presence of piroplasms and Anaplasma species. All investigated cattle were clinically examined. Blood samples were screened for the presence of blood parasites using microscopy and PCR assays. Seventy-one animals were acutely ill, whereas 93 were apparently healthy. In acutely ill cattle, Babesia/Theileria species (n=11) and Anaplasma marginale (n=10) were detected. Mixed infections with Babesia/Theileria spp. and A. marginale were present in two further cases. A. marginale infections were also detected in apparently healthy subjects (n=23). The results of PCR assays were confirmed by DNA sequencing. All samples that were positive by PCR for Babesia/Theileria spp. gave also positive results in the microarray analysis. The microarray chips identified Babesia bovis (n=12) and Babesia bigemina (n=2). Cattle with babesiosis were likely to have hemoglobinuria and nervous signs when compared to those with anaplasmosis that frequently had bloody feces. We conclude that clinical examination in combination with microscopy are still very useful in diagnosing acute cases of babesiosis and anaplasmosis, but a combination of molecular biological diagnostic assays will detect even asymptomatic carriers. In perspective, parallel detection of Babesia/Theileria spp. and A. marginale infections using a single microarray system will be a valuable improvement.

Molecular and serological detection of Babesia Bovis and Babesia Bigemina in cattle in the Rio de Janeiro, Brazil

A babesiose bovina é uma importante doença do gado, onde Rhipicephalus microplus atua como um vetor para os dois organismos causais Babesia bovis e Babesia bigemina. Um total de 22 animais foram aleatoriamente e monitorados durante três anos, por nested PCR e teste de ELISA para determinar a prevalência de B. bovis e B. bigemina. A prevalência global de B. bovis e B. babesia foi de 30% e 35%, em nPCR, e 70% e 75% por ELISA, respectivamente. A análise estatística das características dos animais mostrou que a idade e carrapatos (p &lt;0,05) podem desempenhar um papel importante na propagação de babesiose em animais com menos de 6 meses de idade. Uma correlação elevada (índice Kappa de 0,70 para B. bovis e B. babesia 0,65, respectivamente) entre os testes sorológicos e moleculares sugere que a combinação das técnicas utilizadas no presente estudo é adequado para o diagnóstico da babesiose numa área de instabilidade endémica.

Trichostatin A, a potential drug for treatment of animal Babesia infections

In the present study, we evaluated the inhibitory effect of trichostatin A on the asexual growth of bovine, equine, and canine Babesia parasites in vitro as well as on the in vivo growth of Babesia microti (B.microti) in mice. The growth of Babesia bovis (B.bovis), Babesia bigemina (B.bigemina), Babesia caballi (B.caballi), Theileria equi (T.equi), and Babesia gibsoni (B.gibsoni) species was significantly inhibited (P &lt; 0.05) by very low concentrations of trichostatin A (IC50 values = 2.6, 2.4, 2.3, 2.4, and 2.3 nM, respectively). Furthermore, in B.microti-infected mice, trichostatin A caused significant higher (P &lt; 0.05) inhibition of the growth of B.microti at the dose of 2 mg/kg body weight than that in the control group. These results indicated the trichostatin A might be a chemotherapeutic agent for treatment of babesiosis. DOI: http://dx.doi.org/10.5564/mjas.v11i2.210 Mongolian Journal of Agricultural Sciences Vol.11(2) 2013 pp.24-26

Species distribution modelling for Rhipicephalus microplus (Acari: Ixodidae) in Benin, West Africa: Comparing datasets and modelling algorithms

Rhipicephalus microplus is one of the most widely distributed and economically important ticks, transmitting Babesia bigemina, B. bovis and Anaplasma marginale. It was recently introduced to West Africa on live animals originating from Brazil. Knowing the precise environmental suitability for the tick would allow veterinary health officials to draft vector control strategies for different regions of the country. To test the performance of modelling algorithms and different sets of environmental explanatory variables, species distribution models for this tick species in Benin were developed using generalized linear models, linear discriminant analysis and random forests. The training data for these models were a dataset containing reported absence or presence in 104 farms, randomly selected across Benin. These farms were sampled at the end of the rainy season, which corresponds with an annual peak in tick abundance. Two environmental datasets for the country of Benin were compared: one based on interpolated climate data (WorldClim) and one based on remotely sensed images (MODIS). The pixel size for both environmental datasets was 1km. Highly suitable areas occurred mainly along the warmer and humid coast extending northwards to central Benin. The northern hot and drier areas were found to be unsuitable. The models developed and tested on data from the entire country were generally found to perform well, having an AUC value greater than 0.92. Although statistically significant, only small differences in accuracy measures were found between the modelling algorithms, or between the environmental datasets. The resulting risk maps differed nonetheless. Models based on interpolated climate suggested gradual variations in habitat suitability, while those based on remotely sensed data indicated a sharper contrast between suitable and unsuitable areas, and a patchy distribution of the suitable areas. Remotely sensed data yielded more spatial detail in the predictions. When computing accuracy measures on a subset of data along the invasion front, the modelling technique Random Forest outperformed the other modelling approaches, and results with MODIS-derived variables were better than those using WorldClim data.The high environmental suitability for R. microplus in the southern half of Benin raises concern at the regional level for animal health, including its potential to substantially alter transmission risk of Babesia bovis. The northern part of Benin appeared overall of low environmental suitability. Continuous surveillance in the transition zone however remains relevant, in relation to important cattle movements in the region, and to the invasive character of R. microplus.

Functional genomics of tick vectors challenged with the cattle parasite Babesia bigemina.

Ticks are obligate hematophagous ectoparasites considered as vectors of animal diseases, having a huge economic impact in cattle industry. Babesia spp. are tick-borne pathogens that cause a disease called babesiosis in a wide range of animals and in humans. Control of tick infestations is mainly based on the use of acaricides, which have limited efficacy reducing tick infestations, mostly due to wrong usage, and is often accompanied by the selection of acaricide-resistant ticks, environmental contamination, and contamination of milk and meat products. Vaccines affecting both vector and pathogens constitute new control strategies for tick and tick-borne diseases and are, therefore, a good alternative to chemical control. In this chapter we describe the identification of Rhipicephalus (Boophilus) annulatus genes differentially expressed in response to infection with B. bigemina by using suppression-subtractive hybridization (SSH), which allows the identification of differentially expressed genes. The results of the SSH studies are validated by real-time reverse transcription (RT)-PCR. Functional analyses are conducted by RNAi on selected R. annulatus genes to determine their putative role in B. bigemina-tick interactions. Gathered data may be useful for the future development of improved vaccines and vaccination strategies to control babesiosis.