Management factors associated with Babesia bovis seroprevalence in cattle from eastern Yucatán, Mexico.

The effect of management on the seroprevalence of Babesia bovis was studied in 399 Bos indicus cattle 1–2 years old from 92 farms in the eastern Yucatán, México. The management factors studied were: farm-type, production system, herd size, farm size, stocking density, vector control, dipping interval, type of dipping, type of acaricide and cattle introduction to the farm. A cross-sectional study was carried out (2-stage cluster sampling). The number of serum samples was proportionally distributed according to the number of farms in the nine locations of eastern Yucatán, México (399 animals from 92 farms). Antibody activity to B. bovis was tested using an indirect ELISA. The farms with a seroprevalence ≤75% were considered as cases and those with seroprevalence >75% were considered as controls. The variables with p ≤ 0.20 were included in fixed effects logistic regression. The seroprevalence of the zone was 73.8% (66.3–81.3%). The following risk factors were found: Stocking density (<1 head/ha, OR = 4.04, CI (OR) = 1.20–13.62) and dipping interval (>60 days, OR = 5.07 CI (OR) = 1.26–20.48).     

Estimates of within-herd incidence rates of Mycobacterium bovis in Canadian cattle and cervids between 1985 and 1994

We analysed the individual-animal data from six of the nine outbreaks of tuberculosis in Canadian cattle and cervids from 1985 to 1994. A “positive/reactor” animal was one which had either a positive culture or a positive or suspicious reaction on a mid-cervical, comparative cervical, or gross or histopathological test for tuberculosis. Individual-animal data were collected only for herds which had one or more positive/reactor animals. Data were collected from the outbreak records in the Regional or District offices of Agriculture and Agri-food Canada’s Animal and Plant Health Directorate. The within-herd spread of Mycobacterium bovis was studied by determining the most-likely date at which the herd was first exposed to M. bovis and the number of reactions which had developed by the time the herd was investigated. The animal-time units at risk in the herd were probably overestimated, resulting in conservative estimates of the within-herd incidence rates. Negative-binomial regression was used to investigate factors which might have influenced the within-herd spread of tuberculosis. Increasing age appeared to be a risk factor for being a positive/reactor animal. When compared to animals 0–12 months old, animals 13–24 months old had an incidence rate ratio (IRR) of 7.6, while animals >24 months old had an IRR of 10.4 (p=0.009). Actual and predicted incidence rates for tuberculosis in mature (>24 months old) animals were calculated. Actual and predicted incidence rates were similar for cervids, within an outbreak. There was more variability between actual and predicted rates in the dairy and beef animals. In the one outbreak (Ontario) where there were positive/reactor cervid, dairy and beef herds, the actual incidence rate for cervids (IR=9.3 cases per 100 animal-years) was almost twice that of dairy cattle (IR=5.0) and three times that of beef cattle (IR=3.1).     

Clinicopathological findings, molecular detection and characterization of Babesia gibsoni infection in a sick dog from Italy

A 4-year-old intact female American Pit Bull Terrier from Italy descendant of an American-born bitch was evaluated for anorexia, lethargy, weakness, and intermittent vomiting. On physical examination, the dog was dehydrated, had pale mucous membranes, hunched posture and abdominal pain. A moderate anemia was observed. Splenomegaly and hyperechoic regions suspected as infarcts in the spleen were seen on abdominal ultrasound. Based on the suspicion of splenic torsion, splenectomy was performed. After surgery, the clinical condition deteriorated. A follow-up complete blood count demonstrated severe macrocytic normochromic anemia with evidence of marked regeneration, left shift neutrophilia, monocytosis and marked thrombocytopenia. Blood smear evaluation revealed single to multiple, variable sized (1–3 μm in diameter), and round to oval to band-like piroplasms within many red blood cells consistent with small form Babesia spp. or Theileria spp. A partial segment of the 18S rRNA gene was amplified and the PCR product was analyzed by direct sequencing. The nucleotide sequence was completely identical to that of Babesia gibsoni present in GenBank^®. This is the first molecular detection and characterization of B. gibsoni infection in a sick dog from Italy.     

Seroprevalence and risk factors associated with seropositivity in sows from 67 herds in north-west Germany infected with Mycoplasma hyopneumoniae

Risk factors for the spread of Mycoplasma hyopneumoniae in sows have not been studied although vertical transmission from sows to their offspring is considered a significant risk factor in the development of enzootic pneumonia in growers and finishers. Seropositivity for M. hyopneumoniae in sows, as assessed by commercial ELISA, is a possible indicator of infection pressure among sows. The objective of this study was to estimate seroprevalence and associated risk factors of a sow being seropositive for M. hyopneumoniae. A cross-sectional study was carried out in 2578 sows from 67 herds in north-west Germany. Data concerning general herd characteristics, acclimatisation practices, indoor and outside contacts, as well as data describing the immediate local environment were collected during a herd visit via questionnaire. Blood samples were seropositive in 65% of the 2578 sows, and all herds had ≥14% seropositive sows. Data analysis was performed in two steps. First, univariate analysis of predictor variables for the risk of a sow being seropositive for M. hyopneumoniae was performed using chi-square test. Secondly, all variables associated with the risk of a sow being seropositive (P ≤ 0.25) were included in a multivariate model using a generalised linear model. The risk of a sow being seropositive for M. hyopneumoniae was increased in herds with two- or three-site production (OR 1.50), when piglets were not vaccinated against M. hyopneumoniae (OR 1.81), in herds with a 2-week farrowing intervals (OR 1.84) and in herds without all-in/all-out management of the farrowing units (OR 1.37). The lack of an acclimatisation period for replacement boars was also associated with the risk of a sow being seropositive (OR 2.10). The results indicate that M. hyopneumoniae seropositivity is common in sows in north-west Germany and is influenced by various management factors. It is recommended that evaluation of sow herd management should be included in any strategic health plan to control M. hyopneumoniae infection.     

Persistent immune responses in late infection and after treatment in experimental Schistosoma bovis infections in goats

This study explored host immune responses and their possible relationship to the anti-fecundity phenomenon in Schistosoma bovis-infected goats. The design comprised a primary infection with or without treatment at week (wk) 13, and with or without challenge at wk 36. Necropsy was performed at 36 or 52 wk. Serum levels of anti-egg IgG, and anti-worm IgG and IgM, were measured by ELISA. In chronic infection, anti-worm antibodies stayed high, reflecting persisting worm burdens, whereas anti-egg IgG remained high despite minimized egg excretion. After treatment, anti-worm IgM and anti-egg IgG were minimized, but anti-worm IgG remained above the values of the uninfected controls. Histopathology showed lowered numbers of perioval granulomas in chronic infection and resolution of liver fibrosis with time, but intestinal lymphoplasmacytic perivasculitis and hepatic eosinophilic infiltrates were maintained at wk 52. Significant splenic plasmacytosis persisted after treatment. The results indicated that persistent immune responses, in chronically infected and in treated goats, may explain sustained worm fecundity depression at challenge infection.     

Analyses of lipopolysaccharides, outer membrane proteins and DNA fingerprints reveal intraspecies diversity in Moraxella bovis isolated in Argentina

Intra-specific diversity within Moraxella bovis was investigated analysing DNA fingerprints, outer membrane proteins (OMP) and lipopolysaccharides (LPS) profiles. Three collection strains and 57 isolates of M. bovis, collected during 3 years from cattle with infectious bovine keratoconjunctivitis (IBK) symptoms, from diverse geographical locations of Argentina, were examined. The LPS and OMP profiles were studied through SDS–PAGE analysis and genotype was determined by PCR-DNA fingerprinting. Genotyping identified five DNA types while analysis of LPS and OMP profiles identified three rough LPS types and three OMP types among the 60 isolates of M. bovis including the three collection strains. None of the three methods employed to assess diversity was discriminating when used alone because the degree of heterogeneity in each group of surface structures was limited, but when data of each typing method were combined, 15 distinct subgroups were determined. This subgrouping was clearly able to differentiate isolates of the same genotype. These typing methods appear to be useful to assess different aspects of the disease such as the diversity within a population of M. bovis associated to epidemic conditions, track the causal agent in an outbreak of the disease, monitoring vaccination programs and studies on virulence.     

Cross-sectional study of the seroprevalence to Borrelia burgdorferi sensu lato and granulocytic Ehrlichia spp. and demographic, clinical and tick-exposure factors in Swedish horses

A cross-sectional study of the seroprevalence to Borrelia burgdorferi sensu lato and granulocytic Ehrlichia spp. in Swedish horses was conducted to evaluate associations with demographic, clinical and tick-exposure factors. From September 1997–1998, blood samples from 2018 horses were collected from the animals presented to veterinary clinics affiliated with the Swedish Horserace Totalizator Board (regardless of the primary cause for consultation). Standardized questionnaires with information both from owners and attending veterinarians accompanied each blood sample. The apparent seroprevalences to B. burgdorferi s. l. and granulocytic Ehrlichia spp. were 16.8 and 16.7%, respectively. The northern region had the lowest seroprevalences. Four logistic models were developed (controlling for demographic variables). In the disease model of seropositivity to B. burgdorferi s. l., age, breed, geographic region, the serologic titer to granulocytic Ehrlichia spp., season and the diagnosis coffin-joint arthritis were significant. In the tick-exposure model of B. burgdorferi s. l., pasture access the previous year and gender were significant. Age, racing activity, geographic region, season and the serologic titer to B. burgdorferi s. l. were associated with positivity to granulocytic Ehrlichia spp. In the tick-exposure model of granulocytic Ehrlichia spp., pasture access was a risk factor. An interaction between racing activity and geographic region showed that the risk of positive serologic reactions to Ehrlichia spp. was increased in the horse population in the south and middle of Sweden, but only among horses not used for racing. Except for the positive association between coffin-joint arthritis and serologic reactions to B. burgdorferi s. l., there were no significant associations in the multivariable models between non-specific or specific clinical sign or disease with seropositivity to either of these agents.     

Monitoring of leptospirosis seroprevalence in a colony of captive collared peccaries (Tayassu tajacu) from the Peruvian Amazon

Leptospirosis, an endemic zoonoses, is maintained in the environment by several wildlife species in the Peruvian Amazon. In order to evaluate the possible role of collared peccaries (CP) in the maintenance this disease, two serological surveys of leptospirosis were performed and zootechnical parameters were monitored in a captive CP colony in an interval of 27 months. Total seroprevalence changed from 100% (n = 27) to 86.4% (n = 22), with reactions to a diversity of serogroups of zoonotic importance. Serological reactions to Leptospira licerasiae serogroup Iquitos, a new species recently identified locally and Leptospira interrogans serogroup Icterohaemorrhagiae were highly prevalent. The observation of leptospiral antibodies in both surveys, changes on serological reactions to different serogroups in large part of the herd and poor reproductive performances, provided an indication of the role of CP farms as a favourable environment for maintaining leptospirosis. Further research regarding the role of CP in the epidemiology of leptospirosis in the Peruvian Amazon is encouraged.     

Enhanced resistance to Listeria monocytogenes in mice injected with either whole cells or fractions of the aerobic corynebacterium, Corynebacterium catarrhalis

Resistance of mice to Listeria monocytogenes was shown to be enhanced by pretreatment with either intact or delipidated whole cells of a new species of aerobic corynebacteria, designated as Corynebacterium catarrhalis, as well as with fractions isolated therefrom. Both whole cells and a particulate fraction (CBAp40) proved to be effective when given intravenously, whereas a water-soluble fraction (CBA-LS) was not. In contrast, CBA-LS, as well as CBAp40 and whole cells were found to be effective when given subcutaneously as far as they had previously been adsorbed onto a gel of either calcium phosphate or aluminum hydroxide. Furthermore, pretreatment of mice with either of the mineral gels in the absence of the products failed to confer protection on them to the challenge with L. monocytogenes. It is suggested that C. catarrhalis or products derived therefrom could be used as agents for enhancing resistance to infections of immuno-compromised individuals.     

Prevalence of agglutinating antibodies to Sarcocystis neurona in raccoons, Procyon lotor, from the United States

Equine protozoal myeloencephalitis (EPM) is the most important protozoal disease of horses in North America and it is caused by Sarcocystis neurona. Natural cases of encephalitis due to S. neurona have been reported in raccoons, Procyon lotor. We examined 99 raccoons for agglutinating antibodies to S. neurona using the S. neurona agglutination test (SAT) employing formalin-fixed merozoites as antigen. Raccoons originated in Florida (N=24, collected in 1996), New Jersey (N=25, collected in 1993), Pennsylvania (N=25, collected in 1999), and Massachusetts (N=25, collected in 1993 and 1994). We found that 58 (58.6%) of the 99 raccoons were positive for antibodies to S. neurona using the SAT; 44 of 99 raccoons (44%) had titers of ≥1:500. This prevalence is similar to the reported seroprevalence of 33–60% for S. neurona antibodies in horses from the United States using the Western blot test.     

The bovine annexin 9 gene (ANXA9) is significantly associated with milk-fat yield in a Spanish Holstein–Friesian population

On the basis of QTL studies for milk-fat yield trait on BTA3, annexin 9 protein (ANXA9), fatty acid transport protein type 3 (SLC27A3) and diacylglycerol O-acyltransferase 1 (DGAT1) were selected as candidate genes. Three different single nucleotide polymorphisms (SNPs) of bovine ANXA9, SLC27A3 and DGAT1 genes have been tested in a selective genotyping design for milk-fat yield. Significant allele frequency differences were found for ANXA9 (p = 0.02), in Holstein–Friesian animals with high and low breeding values for milk-fat yield. Regression analysis also showed a significant effect (p = 0.0207) between estimated breeding values (EBVs) for fat milk content and ANXA9 polymorphism. So ANXA9 gene falls into a significant quantitative trait loci interval for milk-fat yield that was previously reported on bovine chromosome 3 in other dairy populations. Our results suggest that the ANXA9 gene polymorphism or a linked segregating QTL contributes to variation in milk-fat yield.     

Host factors associated with the detection of Aeromonas salmonicida and Yersinia ruckeri in Ontario, Canada government fish hatcheries

This paper presents an epidemiological investigation of Ontario Ministry of Natural Resources Fish Health Laboratory data from 1981 to 1997, to determine whether fish species and age were associated with lot-level detection of Aeromonas salmonicida and Yersinia ruckeri in hatchery fish. In stepwise logistic regression, the species brook trout and back-cross (lake trout crossed with the hybrid “splake”) were more likely to test A. salmonicida-positive compared to all other species reared in the hatcheries. Similarly, the species brook trout was significantly more likely to test Y. ruckeri-positive compared to all other species. For both pathogens, the 1–5-month age group was associated significantly with detection. These findings suggest that purposive sampling of higher-risk fish lots could increase the likelihood of detecting both study pathogens.     

Canine babesiosis caused by Babesia canis vogeli in rural areas of the State of Minas Gerais, Brazil and factors associated with its seroprevalence

This epidemiological survey on canine babesiosis was carried out in three distinct rural regions (Lavras, Belo Horizonte and Nanuque) of the State of Minas Gerais, Brazil. Ticks and blood samples were collected during a dry season (Lavras, n = 92; Belo Horizonte, n = 50; Nanuque, n = 102) and the subsequent rainy season (Lavras, n = 71; Belo Horizonte, n = 28; Nanuque, n = 66) from dogs living on farms. Plasma samples were analyzed by the indirect fluorescent antibody test for detection of anti-Babesia canis vogeli antibodies. DNA was extracted from blood of serologically positive dogs and molecular characterization of Babesia species was performed. Rhipicephalus sanguineus, Amblyomma cajennense and Boophilus microplus were the tick species identified in all regions. In Lavras, in addition to those tick species, A. tigrinum and A. ovale were also identified. The most prevalent tick species was A. cajennense (35.3%), followed by R. sanguineus (19%) and B. microplus (4.0%). Dogs living in Nanuque region were more heavily infested with ticks than dogs living in Belo Horizonte and Lavras regions. The overall frequency of anti-B. c. vogeli antibodies in the canine population in rural areas of Minas Gerais was 28.7%, with prevalence rates of 49.0% in Nanuque, 34.0% in Belo Horizonte and 3.3% in Lavras. The age of the animals and tick infestation were associated with seroprevalence of B. c. vogeli. The sequence analysis showed that B. c. vogeli was the only Babesia species present in all three regions. This study showed different rates of prevalence and incidence of canine babesiosis among the three rural regions sampled in Minas Gerais State. The results point to the importance of canine babesiosis in rural areas and to the need for further studies related to its transmission and maintenance in nature.     

Prevalence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies in sheep from Mossoró, Rio Grande do Norte, Brazil

Toxoplasma gondii is an obligate intracellular parasite with a variety of hosts, responsible for reproductive problems and economic losses in sheep flocks. Neospora caninum was recently identified and its clinical presentation in sheep is similar to that of toxoplasmosis, which can cause repeated abortions, though less frequently in this species. In order to confirm the prevalence of these agents in the city of Mossoró, Rio Grande do Norte, Brazil, 409 serum samples from adult sheep (364 females and 45 males) were tested by the indirect immunofluorescence antibody test, using cut-off point at a dilution of 1:64 and 1:50 for T. gondii and N. caninum, respectively. From the 35 properties examined, 23 (65.7%) had at least one seropositive animal for T. gondii and six (17.1%) for N. caninum. The prevalence of seropositive animals for T. gondii was 20.7% and for N. caninum 1.8%. There was no association between the presence of the agent’s antibody and gender, reports of reproductive problems and presence of dogs and/or cats in the properties. T. gondii is well distributed and N. caninum has low prevalence in sheep and in the properties of the studied region.     

IgG, IgM and IgA in the serum of cattle naturally infected with Mycobacterium paratuberculosis

Serum IgG, IgM and IgA antibody response in 20 cattle naturally infected with Mycobacterium paratuberculosis and in 15 non-infected cattle were measured by enzyme-linked immunosorbent assay. A strong IgG response was detected in 16 (80%) of the infected animals. Diagnostic levels of IgM were detectable in all of the infected animals as well as in 8 (53%) of the non-infected animals. Animals with paratuberculosis had a very weak specific serum IgA response and this appears to be of little value in detection of infection in these animals.     

Endophily in Culicoides associated with BTV-infected cattle in the province of Limburg, south-eastern Netherlands, 2006

Culicoides were captured at a BTV-infected dairy near Gulpen in the province of Limburg (south-east Netherlands) between 14 September and 4 October 2006. Onderstepoort-type blacklight traps were used to sample Culicoides both inside and outside a partially open shed housing 11 cattle. A total of 28 light trap collections were made at the shed and yielded:

• 9371 Culicoides representing 11 species; >90% comprised five potential vectors of BTV and in order of abundance were Culicoides obsoletus and Culicoides scoticus (of the Obsoletus Complex), Culicoides dewulfi, Culicoides pulicaris and Culicoides chiopterus; Culicoides imicola, the principal Mediterranean (and African) vector of BTV, was absent.

• 2339 Culicoides representing seven species were captured inside (endophily) the cattle shed; >95% comprised the Obsoletus Complex and C. dewulfi. Conversely, the Pulicaris Complex, represented by five species and including C. pulicaris, showed strong exophily with >97% captured outside the shed.

• 7032 Culicoides were captured outside the shed, approximately threefold more than inside. This trend was reversed on an overcast day, when eightfold more Culicoides were captured inside; this indicates that when the light intensity outdoors is low Culicoides will attack (i) earlier in the day while cattle are still at pasture, and (ii) might follow cattle into the sheds in the late afternoon leading to elevated numbers of biting midges being trapped inside the shed during the subsequent hours of darkness.

• Culicoides were captured inside the shed on all 14 sampling nights. On occasion up to 33% were freshly blood fed indicating they had avidly attacked the cattle inside (endophagy); because half the cattle had seroconverted to BTV, and because no cattle were left outdoors at night, the data indicate that (i) the housing of animals in partially open buildings does not interrupt the transmission of BTV, and/or (ii) BTV is being transmitted while cattle are grazing outdoors during the day.

• The capture of partially engorged midges inside the shed shows they are being disturbed while feeding; this may lead to cattle being attacked repeatedly, and if these attacks include older parous BTV-infected Culicoides, may enhance virus dissemination (particularly in sheds where cattle stand close together).

• Endo- and exophagy by potential vector Culicoides – coupled to increased adult longevity and multiple feeding events in single (potentially) infected midges – would ensure an R₀ of >1, resulting in the continued maintenance and spread of BTV within local vertebrate populations.

• Four light trap collections made additionally in a mature deciduous forest 70 m from the shed yielded a high proportion (48%) of gravid females amongst which 10% had incompletely digested blackened blood meals in their abdomens; the absence of this age category in Culicoides captured at the sheds indicates that all Culicoides, after engorgement, exit the buildings to undergo oogenesis elsewhere.

In Europe, the blacklight trap is used widely for the nocturnal monitoring of Culicoides; a drawback to this approach is that this trap cannot be used to sample midges that are active during the day. Because diurnal biting in vector Culicoides may constitute a significant and underestimated component of BTV transmission a novel capture methodology will be required in future and is discussed briefly.     

Vaccination of calves with Mycobacteria bovis Bacilli Calmete Guerin (BCG) induced rapid increase in the proportion of peripheral blood γδ T cells

Changes in the proportion of peripheral blood T cell subsets after subcutaneous inoculation of cattle with Mycobacterium bovis Bacille Calmette-Guerin (BCG) were studied. Calves were injected with approximately 8 × 10⁶ BCG bacillus and blood samples collected at weekly intervals for flow-cytometric analyses to determine the proportion of CD4⁺, CD8⁺ and γδ T cells. In addition, whole blood samples were stimulated in vitro with M. bovis purified protein derivative (PPD) and the secreted IFN-γ quantified by ELISA. Results showed cellular and cytokine changes which could be categorized into three phases. The first phase occurred within the first 2 weeks after vaccination involving an increase in proportion of WC1⁺ γδ T cells and a concomitant increase in the secretion of IFN-γ. These two responses peaked at 2 weeks and waned thereafter. The second phase involved an increase in the CD4/CD8 ratio as a result of an increase in the proportion of CD4⁺ T cells between 4 and 6 weeks. The third phase involved a decrease in the CD4/CD8 ratio due to an increase in the proportion of CD8⁺ T cells between 8 and 10 weeks. Surprisingly, the IFN-γ response was associated with changes in the γδ rather than the CD4⁺ or CD8⁺ T cells, suggesting that this cytokine was secreted by γδ-T cells. These results are consistent with the reported ability of γδ T cells to act rapidly and bridging the innate and classically adaptive immune responses.     

Seroprevalence and risk factors associated with Toxoplasma gondii infection in pig farms from Catalonia, north-eastern Spain

Seroprevalence and associated risk factors for Toxoplasma gondii infection in pigs were analyzed in 1202 sera samples, including sows and pigs of three, seven, 11, 15 and 20 weeks of age, from 23 farms in Catalonia, north-eastern Spain. Antibodies were tested by the modified agglutination test (MAT) at titers ?1:25. Antibodies to T. gondii were found in 228 samples (19.0%; 95% CI: 16.8-21.2). The individual prevalence in animals higher than 7 weeks of age was 22.8% (174/762; 95% CI: 16.6-29.0) and the within-farm prevalence ranged from 7.1% to 36.4%. Statistically significant differences were found among age classes. The risk factors significantly associated with T. gondii seroprevalence were the presence of cats, percentage of mortality at weaning and the presence of outdoor facilities in the farms. The seroprevalence observed in the present study indicates widespread exposure to T. gondii among domestic pigs in Catalonia, which may have important implications for public health.     

Characterization of shiga toxin-producing Escherichia coli strains isolated from calves in Poland

Fecal samples from 67 3–5-months-old calves with diarrhea were screened for the presence of shiga toxin-producing Escherichia coli (STEC). Several accessory virulence factors genes were also tested. Among 192 E.coli isolates tested, 15 (7.6%) were found to harbour the shiga toxin 1 or 2 (stx1 or stx2) genes. The stx2-carrying samples were further subtyped by PCR for the stx2c, stx2d, and stx2e toxin variants. It was shown that stx2-positive bacteria mainly possessed the stx2c shiga toxin type gene. The enterohemolysin (hlyA) and intimin (eae) genes were found in seven (46.7%) STEC strains whereas the cytotoxic necrotizin factor 1 and 2 or the P fimbrial genes were detected in two isolates only. This study confirmed that calves are a reservoir of STEC strains (with all pathogenicity genes) that may be virulent for humans.     

Antibody-ELISA for Trypanosoma evansi: Application in a serological survey of dairy cattle, Thailand, and validation of a locally produced antigen

Trypanosoma evansi is generally considered a mild pathogen in bovines. However, in Asia, acute and chronic signs have been observed in cattle, with high levels of parasitaemia, abortion and death. Investigations in Asian cattle are needed to better understand this epidemiological situation. To generate comparable data at a regional level, development and standardization of an antibody-enzyme linked immunosorbent assay for T. evansi (ELISA/T. evansi) was initiated and applied in an epidemiological survey carried out in dairy cattle in Thailand. A batch of 1979 samples was collected from dairy farms located throughout the country's four regions. Soluble T. evansi antigens initially produced in France were also produced in Thailand for comparison and technology transfer. Screening of 500 samples allowed us to identify reference samples and to determine the cut-off value of the ELISA. Seropositive animals – some of them confirmed by PCR – were found in the four regions, in 12 out of 13 provinces, in 22 out of 31 districts, in 56 farms out of 222 (25%, 95%CI ± 6%) and in 163 animals out of 1979 (8.2, 95%CI ± 1.2%). Estimated seroprevalence in 35 farms ranged between 1% and 30%, and in 21 farms it was >30%. Approximately 25% of survey cattle were exposed to the infection, in various situations. A sub-sample of 160 sera was tested on both antigens. Wilcoxon's (Z = 1.24; p = 0.22) and McNemars's tests (CHI2 = 3.55; p = 0.09) did not show any significant differences, showing that the locally produced antigen is suitable for further evaluation in the surrounding countries. Use of this standardized serological method will broaden knowledge of the prevalence and impact of the disease at the regional level in South-East Asia. Further validation of this ELISA will be necessary in other host species such as buffalo, horse and pig.