Assessment of Babesia spp. prevalence in various domestic animals across Southern Punjab, Pakistan.

Parasitic diseases, notably babesiosis, exert a substantial impact on the global cattle industry, posing challenges to commerce, economies, and human health. This study, conducted in Southern Punjab, Pakistan, aimed to assess the prevalence of Babesia spp. across various livestock species using microscopic and PCR methods. A total of 180 blood samples (60 from each district) were systematically collected from apparently healthy animals, with 36 samples obtained from each domestic animal species, including camel, cattle, buffalo, goat, and sheep, noting that 12 samples were collected from each district for each animal species. Overall prevalence was determined to be 32.8% (59/180), with varying rates among species: 25.0% in cattle, 41.66% in buffalo, 30.55% in goats, 33.3% in sheep, and 33.3% in camels. Microscopic examination revealed slightly varied infection rates among large and small domestic animals (22.2%), while PCR results indicated a 32.8% overall infection rate in both large and small domestic animals, with no statistical significance. District-wise analysis showed regional variations, with Muzaffargarh recording a prevalence rate of 23.33% through microscopic examination, while Lodhran and Bahawalpur recorded 21.67%. PCR results revealed higher rates (38.33%, 26.67%, and 33.33%, respectively), underlining the importance of employing PCR for accurate detection. Examining ruminant types, large ruminants exhibited a 32.4% infection rate, while small domestic animals showed 33.3%, with no significant difference (p=0.897). District-wise prevalence showcased significant variation, with Muzaffargarh demonstrating a 25% prevalence, Lodhran 22%, and Bahawalpur 22%, through microscopic examination. PCR results displayed 38.33%, 27%, and 33.3%, respectively, with no statistical significance. Detailed analysis of individual districts highlighted variations in infection rates among camels, cattle, buffalo, goats, and sheep. The binomial test indicated significant differences through microscopic analysis (P=0.011) but non-significant variations through PCR (P=0.065), emphasizing the precision of PCR. Regional variations in prevalence, notably with Punjab exhibiting the highest frequency (33.87%) and KPK the lowest (13.24%), suggest potential influences from varying veterinary practices and environmental factors. This study underscores the pivotal role of PCR alongside microscopy for accurate babesiosis diagnosis. These findings contribute to the broader understanding of babesiosis prevalence, emphasizing the necessity of advanced molecular techniques for informed control measures.

Risk of transfusion-transmitted Babesia microti in Canada.

BACKGROUND: Babesia microti has gained a foothold in Canada as tick vectors become established in broader geographic areas. B. microti infection is associated with mild or no symptoms in healthy individuals but is transfusion-transmissible and can be fatal in immunocompromised individuals. This is the first estimate of clinically significant transfusion-transmitted babesiosis (TTB) risk in Canada. STUDY DESIGN AND METHODS: The proportion of B. microti-antibody (AB)/nucleic acid amplification test (NAT)-positive whole blood donations was estimated at 5.5% of the proportion of the general population with reported Lyme Disease (also tick-borne) based on US data. Monte Carlo simulation estimated the number and proportion of infectious red cell units for three scenarios: base, localized incidence (risk in Manitoba only), and donor study informed (prevalence from donor data). The model simulated 1,029,800 donations repeated 100,000 times for each. RESULTS: In the base scenario 0.5 (0.01, 1.75), B. microti-NAT-positive donations would be expected per year, with 0.08 (0, 0.38) recipients suffering clinically significant TTB (1 every 12.5 years). In the localized incidence scenario, there were 0.21(0, 0.7) B. microti-NAT-positive donations, with 0.04 (0, 0.14) recipient infections (about 1 every 25 years). In the donor study informed scenario, there were 4.6 (0.3, 15.8) B. microti-NAT-positive donations expected, and 0.81 (0.05, 3.14) clinically significant TTB cases per year. DISCUSSION: The likelihood of clinically relevant TTB is low. Testing would have very little utility in Canada at this time. Ongoing pathogen surveillance in tick vectors is important as B. microti prevalence appears to be slowly increasing in Canada.

Assessment of Babesia bovis 6cys A and 6cys B as components of transmission blocking vaccines for babesiosis.

BACKGROUND: Babesia bovis reproduces sexually in the gut of its tick vector Rhipicephalus microplus, which involves expression of 6cys A and 6cys B proteins. Members of the widely conserved 6cys superfamily are candidates for transmission blocking vaccines (TBV), but intricacies in the immunogenicity of the 6cys proteins in the related Plasmodium parasites required the identification of transmission blocking domains in these molecules for vaccine design. Hereby, the immunogenic efficacy of recombinant (r) B. bovis 6cys A and B proteins as a TBV formulation was studied. METHODS: The immunogenicity of r6cys A and 6cys B proteins expressed in a eukaryotic system was evaluated in a cattle immunization trial (3 immunized and 3 control calves). A B. bovis sexual stage induction in vitro inhibition assay to assess the ability of antibodies to block the production of sexual forms by the parasite was developed. RESULTS: Immunized cattle generated antibodies against r6cys A and r6cys B that were unable to block sexual reproduction of the parasite in ticks. Additionally, these antibodies also failed in recognizing native 6cys A and 6cys B and peptides representing 6cys A and 6cys B functional domains and in inhibiting the development of sexual forms in an in vitro induction system. In contrast, rabbit antibodies generated against synthetic peptides representing predicted B-cell epitopes of 6cys A and 6cys B recognized recombinant and native forms of both 6cys proteins as well as peptides representing 6cys A and 6cys B functional domains and were able to neutralize development of sexual forms of the parasite in vitro. CONCLUSIONS: These data, combined with similar work performed on Plasmodium 6cys proteins, indicate that an effective 6cys protein-based TBV against B. bovis will require identifying and targeting selected regions of proteins containing epitopes able to reduce transmission.

Stochastic Model of Bovine Babesiosis with Juvenile and Adult Cattle.

A stochastic model for Bovine Babesiosis (BB) including ticks, and both juvenile and adult cattle is developed. This model is formulated by a system of continuous-time Markov chains (CTMCs) that is derived based on an extension of the deterministic ordinary differential equation model developed by Saad-Roy et al. (Bull Math Biol 77:514-547, 2015). The nonlinear CTMC model is approximated by a multitype branching process, giving a theoretical estimate of the probability of an outbreak of BB. Unlike the deterministic dynamics where the basic reproduction number is a sharp threshold parameter, the stochastic model indicates that there is always a positive probability of disease extinction within the cattle population. For parameter values from Colombia data, conditional probability distributions are numerically obtained for the time to disease extinction or outbreak, and are found to depend on the host type at the initiation of infection. The models with and without the inclusion of juvenile cattle are compared, and our result highlights that neglecting juvenile bovine in the models may lead to faulty predictions of critical disease statistics: particularly, it may underestimate the risk of infection. Endemic disease prevalence in adult cattle is examined for certain parameter values in the corresponding deterministic model. Notably, with long-lasting immunity, increased tick to juvenile infectivity decreases the proportion of infectious adults.

Zoonotic Babesia: A scoping review of the global evidence.

BACKGROUND: Babesiosis is a parasitic vector-borne disease of increasing public health importance. Since the first human case was reported in 1957, zoonotic species have been reported on nearly every continent. Zoonotic Babesia is vectored by Ixodes ticks and is commonly transmitted in North America by Ixodes scapularis, the tick species responsible for transmitting the pathogens that also cause Lyme disease, Powassan virus, and anaplasmosis in humans. Predicted climate change is expected to impact the spread of vectors, which is likely to affect the distribution of vector-borne diseases including human babesiosis. METHODS: A scoping review has been executed to characterize the global evidence on zoonotic babesiosis. Articles were compiled through a comprehensive search of relevant bibliographic databases and targeted government websites. Two reviewers screened titles and abstracts for relevance and characterized full-text articles using a relevance screening and data characterization tool developed a priori. RESULTS: This review included 1394 articles relevant to human babesiosis and/or zoonotic Babesia species. The main zoonotic species were B. microti, B. divergens, B. duncani and B. venatorum. Articles described a variety of study designs used to study babesiosis in humans and/or zoonotic Babesia species in vectors, animal hosts, and in vitro cell cultures. Topics of study included: pathogenesis (680 articles), epidemiology (480), parasite characterization (243), diagnostic test accuracy (98), mitigation (94), treatment (65), transmission (54), surveillance (29), economic analysis (7), and societal knowledge (1). No articles reported predictive models investigating the impact of climate change on Babesia species. CONCLUSION: Knowledge gaps in the current evidence include research on the economic burden associated with babesiosis, societal knowledge studies, surveillance of Babesia species in vectors and animal hosts, and predictive models on the impact of climate change. The scoping review results describe the current knowledge and knowledge gaps on zoonotic Babesia which can be used to inform future policy and decision making.

Research on Babesia: A bibliometric assessment of a neglected tick-borne parasite.

Given the emergence and reemergence of tick-borne diseases, here we assessed the publishing patterns of research focused on Babesia. We also discuss the implications for the articles published in the last decade, and how more clinical and epidemiological information concerning Babesia is still required. The findings of this article would be useful to define research priorities about Babesia and diagnose the important of scientific production on this pathogen.

A flow cytometric assessment of the lymphocyte immunophenotypes in dogs naturally infected with Babesia rossi.

Immunity to Babesia infection requires both innate and acquired responses, including cell mediated- and humoral responses. The aims of this study were to investigate the variation in selected peripheral blood lymphocyte phenotypes in dogs with virulent babesiosis at presentation and over time after treatment, and to determine whether these were correlated with the severity of clinical signs. Forty-four dogs naturally infected with B. rossi were studied and 5 healthy dogs were included as controls. Blood samples were collected from the jugular vein at admission, prior to any treatment, and at 24h and 48-72h. Leukocytes were incubated with canine specific, fluorochrome conjugated anti-CD3, anti-CD4, anti-CD8, and anti-B cell markers. Babesia-infected dogs were divided into complicated or uncomplicated groups on clinical grounds and in-house laboratory assays. The percentage CD3+ lymphocytes in the complicated group was lower compared to the controls (P=0.014) and uncomplicated group (P=0.007). The percentage CD4+ T lymphocytes in the complicated group was lower compared to the controls (P=0.027) and uncomplicated group (P=0.014). Both the complicated as well as the uncomplicated groups expressed a lower percentage CD8+ T lymphocytes compared to the control group (P<0.001 and P=0.005, respectively). The percentage B lymphocytes was higher in the complicated group at 48-72h. These findings could indicate the presence of a functional immune suppression secondary to increased apoptosis or redistribution of effector lymphocytes and/or a combination of other immune modulatory mechanisms induced by B. rossi infection.

Assessment of Theileria equi and Babesia caballi infections in equine populations in Egypt by molecular, serological and hematological approaches.

BACKGROUND: Equine piroplasmosis (EP) caused by Theileria equi, Babesia caballi, or both, contributes to significant economic loss in the equine industry and remains uncontrolled in Egypt. This study focuses on surveying T. equi and B. caballi infections and hematological disorders in equine populations in Egypt. METHODS: Theileria equi and B. caballi infections were assessed in blood from 88 horses and 51 donkeys in Egypt using light microscopy, indirect immunofluorescent antibody test (IFAT), nested PCR (nPCR), and competitive-ELISA (cELISA) assays. PCR products were examined for specificity by DNA sequencing. Hematological alterations were evaluated using a standard cell counter. RESULTS: Microscopic analysis revealed EP infection in 11.4% and 17.8% of horses and donkeys respectively. IFAT detected 23.9% and 17.0% infection of T. equi and B. caballi, respectively, in horses, and 31.4% of T. equi and B. caballi in donkeys. T. equi cELISA detected 14.8% and 23.5% positive horses and donkeys, respectively, but the B. caballi RAP-1-based cELISA failed to detect any positives, a result hypothesized to be caused by sequence polymorphism found in the rap-1 genes. Nested-PCR analysis identified 36.4% and 43.1% positive horses and donkeys, respectively for T. equi and it also identified 19.3% and 15.7% positive horses and donkeys, respectively for B. caballi. The overall EP incidence found in the population under study was relatively high and comparable regardless of the diagnostic method used (56.8% using nPCR and 48.9% using IFAT). Hematologic analysis revealed macrocytic hypochromic anemia and thrombocytopenia in all piroplasma-infected horses. CONCLUSIONS: The data confirm relatively high levels of EP, likely causing hematological abnormalities in equines in Egypt, and also suggest the need for an improved serological test to diagnose B. caballi infection in this region.

Canine babesiosis in northwestern India: molecular detection and assessment of risk factors.

In the current study, a total of 214 blood samples from dogs in and around Ludhiana, Punjab (India), suspected for canine babesiosis were examined with conventional and molecular assays. Examination of Giemsa-stained peripheral thin blood smears revealed an overall prevalence of 7.47% (16/214) for canine babesiosis encompassing 0.93% (2/214) of large Babesia and 6.54% (14/214) of Babesia gibsoni. However, molecular diagnosis revealed 15.42% (33/214) samples positive for B. gibsoni infection as evident by the presence of 671 bp amplicon. The results of multivariate analysis showed that the prevalence of B. gibsoni was associated with various risk factors, namely, age (P<0.001; OR: 0.398; CI 95%: 0.080-1.799), sex (P=0.022; OR: 0.849; CI 95%: 0.403-1.791), breed of host (P=0.371; OR: 3.345; CI 95%: 1.045-10.710), and season (P=0.230; OR: 2.143; CI 95%: 0.788-5.830). The prevalence of B. gibsoni was higher in summer as compared to winter season and in younger dogs, while breed and sex of the host were not significantly associated with the occurrence of the disease.

Molecular prevalence of Babesia bigemina and Trypanosoma evansi in dairy animals from Punjab, India, by duplex PCR: a step forward to the detection and management of concurrent latent infections.

Specific duplex polymerase chain reaction (PCR) was employed on 411 (386 cattle and 25 buffaloes) blood samples of dairy animals from 9 districts of Punjab, India, for simultaneous detection of Babesia bigemina and Trypanosoma evansi. The results were compared and correlated with conventional Giemsa stained thin blood smear (GSTBS) examination and haematological alterations to know the clinical status and pathogenicity of infections. The Bg3/Bg4 and TR3/TR4 primers were used in duplex PCR for B. bigemina and T. evansi amplified products of 689 bp and 257 bp, respectively. The overall prevalence by duplex PCR was found to be 36.49, 2.43, and 3.41% for T. evansi, B. bigemina, and dual infection, respectively. A more significant difference was observed for dual infection status (P ≤ 0.005) as compared to T. evansi (P ≤ 0.05) and B. bigemina (P ≤ 0.01) among various districts under study. A very low prevalence of T. evansi (0.73%) and B. bigemina (0.48%) was seen by GSTBS. The highly sensitive, specific, and cost-effective duplex PCR was able to detect latent T. evansi and B. bigemina infection in cattle and buffaloes. Haematological evaluation revealed marked pathology in B. bigemina infected group and in dual infected group in contrast to that infected with T. evansi alone.

Assessment of exposure to piroplasms in sheep grazing in communal mountain pastures by using a multiplex DNA bead-based suspension array.

BACKGROUND: Piroplasms are tick-borne hemoprotozoans with a major impact on extensive management systems. Detection of sub-clinical low-level carriers, which can act as source of infection for vector ticks, is key to protect livestock trade and facilitate preventive control programs. The purpose of this study was to develop a method for the detection of ovine piroplasms and to use it in a field study aimed at investigating piroplasms infection in semi-extensive production systems in the Basque Country (northern Spain). METHODS: A DNA bead-based suspension array using the Luminex xMAP technology that included a generic Theileria-Babesia control probe, 6 species-specific probes, and an internal control probe was developed to detect and identify piroplasms that infect sheep. To monitor piroplasm infection in clinically healthy sheep from 4 flocks that share communal mountain pastures, blood samples were collected during 2 grazing seasons. RESULTS: Piroplasms were detected in 48% (214/446) of blood samples, nearly half of them (49.1%, 105/214) as mixed infections. Five different piroplasms were identified: Theileria sp. OT3 in 34.8% of the samples, Theileria ovis in 20.9%, and at lower prevalences Babesia motasi (12.3%), Theileria luwenshuni/OT1 (10.5%) and Babesia ovis (6.3%). Despite differences among flocks associated to differences in management, an increasing trend in the incidence of piroplasm infection with increasing age of animals after increased tick exposure was observed. This increment could be attributed to continued re-infection associated with re-exposure to ticks at grazing. Ticks were collected from animals (4 species) and vegetation (8 species), and associations between tick abundance seasonality and risk of infection with the different piroplasms were established. CONCLUSION: The multiplex Luminex xMAP procedure is a rapid and high throughput technique that provided highly specific and sensitive identification of single and mixed piroplasm infections in blood of sheep carriers. This study confirmed a situation of endemic stability for piroplasm infection in the region, where infection is present in the absence of clinical signs, and mountain grazing allows for sufficient inoculation rates to maintain such situation.

Assessment of renal dysfunction using urinary markers in canine babesiosis caused by Babesia rossi.

Renal damage is deemed a common, yet poorly documented, complication in canine babesiosis. Serum urea and creatinine are insensitive and non-specific markers of early renal dysfunction and their measurements are influenced by hemolysis caused by babesiosis. Therefore, the aim of this study was to use urinary markers to assess the localization and degree of renal dysfunction in dogs with Babesia rossi infection. Urinary immunoglobulin G (uIgG) and urinary C-reactive protein (uCRP) were measured as markers for glomerular dysfunction, while urinary retinol-binding protein (uRBP) was used as a marker for tubular dysfunction. Eighteen dogs presenting with uncomplicated babesiosis were included and compared with eight clinically healthy dogs. Previously validated commercial ELISA kits were used for the measurement of uIgG, uCRP, and uRBP. Results were related to urinary creatinine concentrations (c). Dogs with babesiosis had significantly higher concentrations of all three measured urinary markers compared to healthy dogs. Except for urinary protein/c ratio (UPC), routine urinary and serum markers for renal function (urine specific gravity (USG), serum urea and creatinine (sCr)) were not significantly different between dogs with babesiosis and healthy dogs. All three urinary markers were positively correlated with each other and with UPC. The data supports the presence of both glomerular and tubular dysfunction in dogs suffering from uncomplicated B. rossi infection. Urinary markers were superior to USG, serum urea and creatinine concentrations for the early detection of renal dysfunction in dogs with babesiosis.

Prevalence of livestock diseases and their impact on livelihoods in Central Equatoria State, Southern Sudan.

A participatory epidemiological (PE) study was conducted in Kajo Keji and Yei Counties, Central Equatoria State, southern Sudan to assess the impact of livestock diseases on livelihoods. A serological survey of tick-borne diseases was conducted to supplement the PE study. PE data collection tools consisted primarily of focus group interviews and key informant interviews supplemented by observation. Information was collected on the social context, history and species of livestock kept. Constraints in livestock keeping were explored through description and probing. Proportional piling on the importance of different diseases and relative incidence scoring were also conducted. 243 sera were collected from cattle and tested for antibodies to Anaplasma marginale, Babesia bigemina, B. bovis, Theileria mutans and T. parva by ELISA. Additionally, 173 blood samples were collected for a PCR assay of T. parva. Livestock diseases were ranked as the most important constraint to livestock keeping. While East Coast fever was ranked as the most important disease in Kajo Keji, diarrhoea in small ruminants was reported as the most important disease in Yei. Serological analyses of the sera indicated that A. marginale, B. bigemina, T. mutans and T. parva were most prevalent. Prevalence of B. bovis was found to be low (4.0% and 7.4% in Kajo Keji and Yei, respectively). 35% of the samples screened with the T. parva p104 gene nested PCR assay were positive. The study concludes that while ECF is the most important disease in Kajo Keji, it was not the case in Yei. Additional epidemiological studies are proposed before control strategies are recommended.

Comparison of indirect fluorescent antibody test (IFAT) and slide enzyme linked immunosorbent assay (SELISA) for diagnosis of Babesia bigemina infection in bovines.

An indirect fluorescent antibody test (IFAT) and slide enzyme linked immunosorbent assay (SELISA) were standardized for the detection of antibodies specific to Babesia bigemina in experimentally infected bovine calves and subsequently used for the screening of naturally infected bovine and bubaline sera. In experimentally infected calves positive reactivity was detected in sera at the earliest on day 7 by both the tests. Serological studies for detection of B. bigemina specific antibodies in 180 cow and 120 buffalo serum samples procured from endemic zones of Uttar Pradesh and Punjab revealed 56.11% and 23.33% seropositivity, respectively, both by SELISA and IFAT. Variation in the reactivity pattern between these tests was found to be non significant. The sensitivity of SELISA was determined to be 94.85% whereas the specificity was 90.85% in comparison to IFAT. The agreement between the two tests by kappa statistics at 95% confidence interval revealed kappa- value of 0.853 that depicts almost a perfect degree of agreement. The findings employing experimental as well as test sera from cattle and buffalo from some of the tick infested zones of India suggested that SELISA could be a useful tool for seroprevalence studies on babesiosis, as the test is less cost intensive with high levels of sensitivity and specificity.

Assessment of primers designed for the subspecies-specific discrimination among Babesia canis canis, Babesia canis vogeli and Babesia canis rossi by PCR assay.

Canine babesiosis is an infectious disease caused by either Babesia gibsoni or Babesia canis protozoans. The latter is also classified under three different phylogenetic groups, referred to as subspecies B. canis canis, B. canis vogeli and B. canis rossi. The objective of the present study was to validate and standardize a PCR assay to discriminate the organisms at the subspecies level. First, the reference sequences of the 18S rRNA, 5.8S rRNA and 28S rRNA genes, including the internal transcribed spacer 1 (ITS1) and 2 (ITS2) of the most common species and subspecies of the genus Babesia were retrieved from the GenBank database. Subspecies-specific primers (BAB3, BAB4 and BAB5) and one genus-specific primer were designed from the alignment of the sequences. The PCR assays were evaluated in three different combinations of primer pairs in order to assure complete specificity for each reaction. The results of the tests had demonstrated effectiveness of the novel primer pairs BAB1/BAB3, BAB1/BAB4 and BAB1/BAB5 for the amplification of the subspecies-specific target fragments of 746 bp (B. c. canis), 546 bp (B. c. vogeli) and 342 bp (B. c. rossi) by PCR. The original enzymatic amplification assays with novel primers reported in this paper were confirmed to be a reliable tool for the specific discrimination among B. canis subspecies by single-step PCR assays.

Estimation of the transmission dynamics of Theileria equi and Babesia caballi in horses.

For the evaluation of the epidemiology of Theileria equi and Babesia caballi in a herd of 510 horses in SW Mongolia, several mathematical models of the transmission dynamics were constructed. Because the field data contain information on the presence of the parasite (determined by PCR) and the presence of antibodies (determined by IFAT), the models cater for maternal protection with antibodies, susceptible animals, infected animals and animals which have eliminated the parasite and also allow for age-dependent infection in susceptible animals. Maximum likelihood estimation procedures were used to estimate the model parameters and a Monte Carlo approach was applied to select the best fitting model. Overall, the results are in line with previous experimental work, and add evidence that the epidemiology of T. equi differs from that of Babesia spp. The presented modelling approach provides a useful tool for the investigation of some vector-borne diseases and the applied model selection procedure avoids asymptotical assumptions that may not be adequate for the analysis of epidemiological field data.

Genome sequence of Babesia bovis and comparative analysis of apicomplexan hemoprotozoa.

Babesia bovis is an apicomplexan tick-transmitted pathogen of cattle imposing a global risk and severe constraints to livestock health and economic development. The complete genome sequence was undertaken to facilitate vaccine antigen discovery, and to allow for comparative analysis with the related apicomplexan hemoprotozoa Theileria parva and Plasmodium falciparum. At 8.2 Mbp, the B. bovis genome is similar in size to that of Theileria spp. Structural features of the B. bovis and T. parva genomes are remarkably similar, and extensive synteny is present despite several chromosomal rearrangements. In contrast, B. bovis and P. falciparum, which have similar clinical and pathological features, have major differences in genome size, chromosome number, and gene complement. Chromosomal synteny with P. falciparum is limited to microregions. The B. bovis genome sequence has allowed wide scale analyses of the polymorphic variant erythrocyte surface antigen protein (ves1 gene) family that, similar to the P. falciparum var genes, is postulated to play a role in cytoadhesion, sequestration, and immune evasion. The approximately 150 ves1 genes are found in clusters that are distributed throughout each chromosome, with an increased concentration adjacent to a physical gap on chromosome 1 that contains multiple ves1-like sequences. ves1 clusters are frequently linked to a novel family of variant genes termed smorfs that may themselves contribute to immune evasion, may play a role in variant erythrocyte surface antigen protein biology, or both. Initial expression analysis of ves1 and smorf genes indicates coincident transcription of multiple variants. B. bovis displays a limited metabolic potential, with numerous missing pathways, including two pathways previously described for the P. falciparum apicoplast. This reduced metabolic potential is reflected in the B. bovis apicoplast, which appears to have fewer nuclear genes targeted to it than other apicoplast containing organisms. Finally, comparative analyses have identified several novel vaccine candidates including a positional homolog of p67 and SPAG-1, Theileria sporozoite antigens targeted for vaccine development. The genome sequence provides a greater understanding of B. bovis metabolism and potential avenues for drug therapies and vaccine development.

Prevalence of blood parasites in cattle from wilayates of Annaba and El Tarf east Algeria.

Between June and September 2002, a preliminary study was conducted to assess the prevalence of blood parasites of cattle in eastern Algeria. Fifty-four bovines of different genotypes were submitted to clinical examination. From each animal, blood smears were made and stained by Giemsa. Four species of parasites, namely Theileria annulata, T. orientalis, Babesia bovis and Anaplasma marginale were encountered. Fifty animals carried single or multiple infections with blood parasites and four were found negative. The rate of single infections (72.3%, n = 39) was almost three times higher than multiple infections (20.3%, n = 11). The high percentage of single infections was recorded with T. annulata (53.7%). However single infection with Anaplasma marginale (7.4 %), B. bovis (5.6%) and T orientalis (5.6%) were very low compared to T. annulata infection. The rates of mixed infection were as follows: T. annulata/A. marginale 9.3%, T. annulata/T. orientalis 5.6%, A. marginale/T. orientalis 3.7% and B. bovis/A. marginale 1.9%.

Babesiosis in China.

The importance of babesiosis in livestock in China is discussed and mainly focused on bovine and equine babesiosis. Babesiosis is still one of the most important diseases affecting livestock and has caused great economic loss. Nine species of Babesia have been recognized in livestock: B. bigemina, B. bovis, B. major, B. motasi, B. ovis, B. perroncitoi, B. trautmanni, B. equi (Theileria equi), B. caballi. The distribution of Babesia follows the distribution of the tick vectors. The main vectors of bovine babesiosis are the one-host tick Boophilus microplus and the three-host ticks Rhipicephalus haemaphysaloides haemaphysaloides, Haemaphysalis punctata and Haemaphysalis longicornis. Bovine babesiosis has caused significant losses in milk and meat from cattle in most parts of China. The disease is also a barrier to improving productivity of local cattle by cross-breeding due to the high mortality of genetically superior but highly susceptible cattle, especially dairy cattle, imported from Babesia-free areas. Dermacentor nuttalli is the major vector of equine babesiosis and the tick is distributed in almost all parts of North China. Outbreaks of equine babesiosis have not been very common, but in some districts the disease has seriously affected horses, donkeys and mules.