Vector ecology of equine piroplasmosis

Quantitative detection of Theileria haneyi in South African horses

Theileria haneyi is an apicomplexan parasite closely related to Theileria equi, a known causative agent of equine piroplasmosis. The molecular distinction between these parasites relies on a nested polymerase chain reaction (PCR) assay, which has been reported to be unreliable. A recently reported indirect ELISA based on equi merozoite antigen 11 (Thema-11) of T. haneyi can detect geographically diverse T. haneyi strains. Since the ema-11 gene is exclusive to T. haneyi, it was chosen as the target for developing a TaqMan minor groove binder (MGB™) quantitative real-time PCR (qPCR). Published T. haneyi ema-11 gene sequences were used to design primers to amplify the ema-11 gene, and ema-11 amplicons from South African samples were cloned and sequenced. An alignment of the South African ema-11 gene sequences with published T. haneyi ema-11 gene sequences enabled the identification of a conserved region for the design of the qPCR assay. The T. haneyi ema-11 (Thema-11) qPCR assay was efficient, specific, and sensitive in detecting T. haneyi ema-11. The detection limit was determined to be 1.169 × 10-3 % parasitized erythrocytes. The performance of the Thema-11 qPCR assay was evaluated together with a T. equi ema-1-specific qPCR assay. Theileria haneyi was detected in 67.6 % of the South African field samples screened, while the occurrence of T. equi based on the quantitative amplification of the ema-1 gene was higher (91.8 %). Our results suggest that combined, the Thema-11 and T. equi ema-1 qPCR assays could detect and differentiate between T. haneyi and T. equi infections.

Risk factors for tick infestation and equine Piroplasmosis infection among draught horses in France

Equine piroplasmosis, caused by the protozoan parasites Babesia caballi and Theileria equi, is endemic in Europe's Mediterranean basin, creating significant health and economic challenges for the equine sector. With no available vaccine, an eco-epidemiological approach is essential in order to identify and implement effective preventive measures. With this aim in view, we identified risk factors associated with B. caballi and T. equi infections and tick infestation for draught horses in the Auvergne-Rhône-Alpes region of France, known for its high piroplasmosis seroprevalence. During the spring of 2021, blood samples from 146 horses and ticks from both hosts and pastures were collected across 38 farms, then analysed using PCR to determine parasite prevalence. Environmental and meteorological data, along with information on management practices and individual horse characteristics, were collected on-site and from national databases. The results showed significant spatial variability in T. equi and B. caballi prevalence in horses, ranging from 25.7 % [95 % CI: 13.1 - 43.6] to 83.7 % [95 % CI: 69.8 - 92.2] and from 0 % [95 % CI: 0.0 - 26.8] to 26.5 % [95 % CI: 15.4 - 41.3], respectively. Among 1046 collected ticks, 3 % carried either a species of Babesia or Theileria and were identified as Dermacentor marginatus, Dermacentor reticulatus or Ixodes ricinus. We showed a stronger link between the environment and tick exposure for T. equi infections, while B. caballi infections were more closely associated with individual horse characteristics and management practices. Key risk factors for tick infestation included environmental conditions (temperature, rainfall, vegetation cover, altitude, etc.) and the presence of wild animals in pastures. These findings provide a valuable foundation on which to develop targeted prevention and control strategies to protect horses in enzootic regions.

First Molecular Characterization of Theileria equi from Northeastern Algeria

PURPOSE

Equine piroplasmosis (EP) is a tick-borne disease that affects equids and is caused by the parasites Theileria equi, Theileria haneyi and Babesia caballi. This disease leads to significant economic losses for the global equine industry. The current study aimed to evaluate the prevalence of Piroplasmida infections in equines from El Tarf, located in northeastern Algeria, and investigate the phylogenetic diversity within isolates obtained from infected equines in this study and between those from previous studies.

METHODS

A total of 120 blood samples were collected from equines in three municipalities of El Tarf. The small subunit of the 18 S rRNA gene, commonly used for genotyping and phylogenetic analysis, was amplified from the positive samples and subsequently sequenced for further analysis.

RESULTS

The study found that 40% of equines were infected with T. equi, while no cases of B. caballi infection were detected. The positivity rate was almost identical across all three municipalities. Four distinct T. equi 18 S rRNA gene sequences were identified in equines from El Tarf. Phylogenetic analysis revealed that these T. equi sequences could be categorized into three distinct clades. The isolates identified in this study grouped into clades A and C, indicating the presence of two genotypes of T. equi 18S rRNA sequences in El Tarf, Northeastern Algeria.

CONCLUSION

The results confirmed a high prevalence of equine piroplasmosis in three municipalities of El Tarf. They also demonstrated that different isolates of T. equi can coexist within the same geographic region, offering additional insight into T. equi sequences. This finding emphasizes the significant implications for the surveillance of Apicomplexan parasites.

Epidemiology and genetic diversity of Theileria equi and Babesia caballi in draft horses in the Distrito Federal, Brazil

Equine piroplasmosis (EP) is a reportable disease according to the World Organization for Animal Health (WOAH), caused by Babesia caballi, Theileria equi and T. haneyi. This syndrome is prevalent in tropical and subtropical regions, including various areas in Brazilian. This study examines EP in the Distrito Federal, Brazil, focusing on prevalence, epidemiological characteristics, and circulating genotypes. Epidemiological data and whole blood samples were collected from horses in the Distrito Federal. DNA was analyzed using qPCR for Theileria sp. and B. caballi, followed by cPCR for 18S rDNA of Theileria sp and rap-1 gene for B. caballi and phylogenetic analysis. Results showed a high EP prevalence (56.23%) among the horses: 49.88% for Theileria sp, 1.47% for B. caballi and 4.89% for both. Phylogenetic analysis indicated genetic similarities with other countries, identifying of T. equi genotypes A and C and B. caballi genotype A. Factors linked to infection, included animals older than five years (p-value = 0.04; OR = 1.71, CI = 1.01-2.87) and health conditions (p-value = 0.049; OR = 1.91, CI = 1.003-3.64) as significantly associated with positivity for Theileria sp. and/or B. caballi. This study contributes to the awareness of the circulation and distribution of T. equi and B. caballi genotypes in Brazil, highlighting the importance of health condition and age as associated factors for infection. These findings deepen our understanding of the need for ongoing surveillance and control measures to manage EP effectively.

Molecular detection of piroplasms, Anaplasma, and Ehrlichia species in Kazakhstan

Tick-borne pathogens (TBPs) are a global public health issue. However, there have been few reports on the prevalence of piroplasms, Anaplasma, and Ehrlichia in Kazakhstan. To understand the distribution of piroplasms, Anaplasma, and Ehrlichia pathogens carried by ticks in Kazakhstan, a total of 10,461 ticks were collected from natural hosts (e.g., cattle, sheep, and horses) in six oblasts in eastern, southern, and western Kazakhstan between 2022 and 2024. After morphological identification, 272 representative ticks were further used for species-level detection and partial genotyping analysis of TBPs. Two Babesia species (Babesia occultans and Babesia caballi), four Theileria species (Theileria orientalis, Theileria equi, Theileria annulata, and Theileria ovis), two Anaplasma species (Anaplasma phagocytophilum and Anaplasma ovis), and three Ehrlichia species were detected. Furthermore, genotype B of B. caballi, genotype 1 (Chitose) of T. orientalis, and genotype A of T. equi were confirmed. For the first time, A. phagocytophilum, three phylogeny-independent Ehrlichia spp., genotype B of B. caballi, and genotype A of T. equi were found in Kazakhstan. These findings expand our understanding of the geographical distribution of piroplasms, Anaplasma, and Ehrlichia in Central Asia.

Occurrence and risk factors of equine piroplasmosis in Portugal: A five-year retrospective study

Equine piroplasmosis (EP) is a tick-borne disease of equids caused by Theileria equi, Theileria haneyi, and Babesia caballi. EP is endemic in most tropical and subtropical regions worldwide, and there is a likelihood that it is also endemic in Portugal. This retrospective study aimed to determine the seroprevalence, prevalence, and potential risk factors of EP in our country over the past five years. A total of 3063 diagnostic test records were analysed. Results from the competitive enzyme-linked immunosorbent assay (cELISA) revealed a seroprevalence of 32.7 % and 15.7 % for T. equi and B. caballi, respectively, with a coinfection rate of 7.4 %. For the indirect fluorescent antibody test (IFAT), 38.8 % of the samples were positive for T. equi, 45.7 % for B. caballi, and 23.1 % for both parasites. Prevalence determined using quantitative polymerase chain reaction (qPCR) showed 40.5 % T. equi-positive cases, 8.3 % B. caballi-positive cases, and 3.2 % mixed infections in the studied population. Considering risk factors, age and season appear to be associated with higher seropositivity, and location was also found to play a significant role. This study represents the first retrospective analysis carried out in Portugal, confirming the endemicity of EP in the country. Further studies are needed to corroborate our findings, to determine actual prevalence and seroprevalence in the Portuguese general equine population, and to identify risk factors better, helping breeders and owners to minimise the health and economic impact of EP.

[Equine piroplasmosis: Case descriptions and overview of the epidemiological situation in Europe with focus on Germany]

Equine piroplasmosis (EP) is caused by Babesia (B.) caballi and Theileria (T.) equi and is transmitted by hard ticks. Predominantly, the Mediterranean region is known as being endemic for both pathogens in Europe. However, autochthonous infections in central European countries such as Germany can no longer be ruled out due to individual case reports in horses without any stays abroad as well as the geographical expansion of the habitats of different tick species. The case reports presented underline the risk of infection for horses travelling to endemic areas and in horses imported from such areas to non-endemic countries. Clinical signs are often unspecific and include fever, icterus, lethargy, inappetence, weight loss, and reduced performance. Mild to severe anemia is the most common hematologic abnormality, but thrombocytopenia has also been described. Direct (polymerase chain reaction, microscopical analysis of blood smears) and indirect detection methods (detection of antibodies) are available for the diagnosis of pathogen contact and/or infection. Imidocarb-dipropionate is recommended as treatment of choice against EP. Infections with B. caballi can be cleared, while infections with T. equi often result in a life-long carrier status despite treatment. Prevention is limited to controlling or avoiding tick contact. Aside from potentially severe and life-threatening clinical signs, equine piroplasmosis has a significant economic impact on the international trade of horses worldwide. EP is classified as a notifiable disease according to WOAH guidelines, which recommend serological screening for B. caballi and T. equi according to the respective national guidelines when travelling across borders. To date, EP is not classified as a notifiable nor reportable disease in Germany.

Evaluation of Theileria equi vertical transmission rate and routes in a cohort of asymptomatic mares and their foals

Equine piroplasmosis is a tick-borne disease mainly caused by Theileria equi and Babesia caballi. The objectives of this study were to analyse the frequency and routes of vertical transmission of these blood parasites from 179 asymptomatic mares to their foals. Foals were sampled within 72 h post-partum. The seroprevalences determined by Indirect Immunofluorescent Antibody Test (IFAT) and based on a subset sample of 107 couples, were 59.8% and 42.1% for T. equi and B. caballi, respectively in the mare population, and 54.2% and 40.2% in the foal population. A species-specific nested PCR was performed on all blood samples (358) and on available samples of placenta (24), umbilicus (6) and colostrum (18). For mares, 30.2% (54/179) and 2.2% (4/179) were PCR-positive for T. equi and B. caballi, respectively. Vertical transmission was not observed in the case of B. caballi, and four foals were born T. equi PCR-positive, giving a transmission rate of 7.4% (4/54). The blood smear evaluation showed viable T. equi parasites for the four foals without clinical signs of neonatal equine piroplasmosis, but one foal had acute renal failure. Theileria equi DNA was detected in umbilical cords, placenta and/or colostrum from PCR-positive mares, without correlation with the carrier status of the foal. One foal was born carrier but T. equi DNA had not been detected in the placenta. The 18S rRNA genotype E of T. equi was characterized in the four foals, foetal parts of the placenta and colostrum. The routes of transmission and particularly the possibility of colostral passage warrant further investigation.

Equine piroplasmosis in different geographical areas in France: Prevalence heterogeneity of asymptomatic carriers and low genetic diversity of Theileria equi and Babesia caballi

Equine piroplasmosis is a worldwide tick-borne disease caused by the parasites Theileria equi sensu lato and Babesia caballi, with significant economic and sanitary consequences. These two parasites are genetically variable, with a potential impact on diagnostic accuracy. Our study aimed to evaluate the frequency of asymptomatic carriers of these parasites in France and describe the circulating genotypes. We developed a species-specific nested PCR protocol targeting the 18S small sub-unit (SSU) rRNA gene and used it on blood samples collected from 566 asymptomatic horses across four National Veterinary Schools. The carrier frequency varied from 18.7 % around Paris (central-north) to 56.1 % around Lyon (southeast), with an overall prevalence of 38.3 %. Theileria equi carriers were ten times more frequent (91.7 %; 209/228 isolates) compared to B. caballi carriers (8.3 %; 19/228 isolates). Notably, T. equi carrier frequency was significantly lower in the northern region (Ile de France) compared to the southeastern regions. A positive relationship was observed between the frequencies of asymptomatic carriers and the frequency of previous acute piroplasmosis reported from the owner across all four geographic areas. Neither horse gender nor age showed a significant effect on the frequency of asymptomatic carriers. In some areas, a substantial proportion of horses (22.2 % to 37.5 %) carried T. equi before the age of three years, indicating high infection pressure. Genotyping of 201 T. equi isolates revealed a predominance of genotype E (98 %) and few isolates belonging to genotype A (2 %). Notably, two of the four T. equi genotype A isolates were detected in horses originating from Spain. All 19 B. caballi isolates belonged to the genotype A. The discussion section explores the link between these results, the tick distribution and abundance, and the frequency of detection of T. equi and B. caballi in febrile cases attributed to piroplasmosis.

Molecular Investigations of Babesia caballi from Clinically Healthy Horses in Southwestern Romania

Babesia caballi is a tick-borne hemoparasite that causes equine piroplasmosis. It has a significant economic impact, decreasing performance and affecting animal welfare. This study aimed to identify B. caballi DNA in the blood of horses from households in the southwestern and western regions of Romania. We included 310 animals, from which blood was collected via EDTA. To test the samples for the B. caballi parasite genome, we used real-time PCR and conventional PCR. The prevalence of B. caballi was 5.81% (18/310) in apparently healthy horses, suggesting that this parasite is enzootic in the regions studied, although veterinarians did not indicate any symptoms resembling clinical babesiosis. In Romania, there are insufficient epidemiologic data on equine babesiosis, and the results of the present study suggest the need for further investigations into the dynamics of transmission and to identify potential prevention and control strategies.

Molecular prevalence and genotypic diversity of Theileria equi and Babesia caballi infecting horses in Kyrgyzstan

Equine piroplasmosis is caused by Theileria equi and Babesia caballi, which are hemoprotozoan parasites. Understanding the epidemiology and genotypes of T. equi and B. caballi is crucial for developing effective control strategies in endemic countries. However, the endemic status of these two parasite species remains uncertain in Kyrgyzstan due to lack of surveys. Our study, therefore, aimed to detect T. equi and B. caballi infections in Kyrgyzstan and identify their genotypes. Blood samples were collected from 226 horses across all seven provinces of Kyrgyzstan, namely Chuy, Issyk-Kul, Naryn, Talas, Jalal-Abad, Osh, and Batken. These blood samples were subjected to DNA extraction, followed by specific PCR assays targeting T. equi and B. caballi. We found that 56 (24.8%, confidence interval (CI): 19.6-30.8%) and 7 (3.1%, CI: 1.5-6.3%) of the tested horses were positive for T. equi and B. caballi infections, respectively. Theileria equi was detected in all surveyed provinces, whereas B. caballi was found in five provinces, except for Talas and Osh. Subsequent genotype-specific PCR assays showed that T. equi-positive horses harbored all five genotypes: A, B, C (also known as Theileria haneyi), D, and E. On the other hand, phylogenetic analysis of B. caballi rap-1 sequences detected the genotypes A and B1. The prevalence of T. equi and B. caballi suggests a potential risk of clinical equine piroplasmosis among horses in Kyrgyzstan, and the observed genotypic diversity underscores the challenges in managing the disease. Our findings emphasize the need for comprehensive control measures to effectively address equine piroplasmosis in Kyrgyzstan.

Significance of Anaplasma phagocytophilum, Babesia caballi, and Theileria equi as etiologic agents in horses with clinical manifestations from the metropolitan area of Rio De Janeiro, Brazil

Equine Piroplasmosis (EP) and Equine Granulocytic Anaplasmosis (EGA) are diseases that affect horses, transmitted by ixodid ticks, causing a nonspecific febrile syndrome. Equine Piroplasmosis is endemic in Brazil, and most horses are in enzootic stability. Serological and molecular studies carried out on horses in Brazil have shown the presence of Anaplasma phagocytophilum, however, the clinical relevance of this infection has not yet been established. The present study aims to evaluate the importance of Babesia caballi, Theileria equi, and A. phagocytophilum as etiological agents in horses with clinical manifestations suggestive of these diseases in the metropolitan mesoregion of Rio de Janeiro. A total of 45 animals with clinical signs were submitted to DNA extraction followed by qPCR test. Anaplasma phagocytophilum, Neorickettsia risticii and Theileria haneyi were not found in any of the horses with clinical signs, however 62.2% were infected with at least one agent of EP. Theileria equi was the most frequent etiologic agent (35.5%), followed by coinfection (15.5%) and B. caballi (11.2%). These results suggest that A. phagocytophilum has minor clinical importance in the region, while EP is frequently found in symptomatic horses, representing an important differential diagnosis in suspected cases.

First Molecular Evidence of Babesia caballi and Theileria equi in Imported Donkeys from Kyrgyzstan

Equine piroplasmosis (EP) is an important tick-borne disease of equids, caused by Theileria equi, Theileria haneyi, and Babesia caballi. Nonetheless, there has been a scarcity of systematic reports on EP parasites in donkeys in Kyrgyzstan, Central Asia. In this study, piroplasms were screened in 1900 blood samples from imported donkeys from the Osh Oblast (southwestern Kyrgyzstan) by targeting partial 18S ribosomal RNA using the polymerase chain reaction (PCR). Through molecular and phylogenetic analyses, all positive samples were sequenced to identify the species and genotypes. The results indicated the presence of both B. caballi and T. equi, with prevalence rates of 8.4% (160/1900) and 12.2% (232/1900), respectively. By amplifying part of the Erythrocyte Merozoite Antigen 1 (EMA-1) and Rhoptry-Associated Protein (RAP-1) genes, B. caballi genotype B and T. equi genotype A were identified. To the best of our knowledge, this is the first report on piroplasm infection among donkeys from Kyrgyzstan.

New insights in the diagnosis and treatment of equine piroplasmosis: pitfalls, idiosyncrasies, and myths

Equine piroplasmosis (EP) is a global tick-borne disease of equids caused by the intraerythrocytic apicomplexan parasites Theileria equi and Babesia caballi, and the more recently discovered Theileria haneyi. These parasites can be transmitted by several tick species, including Dermacentor, Hyalomma, and Rhipicephalus, but iatrogenic and vertical transmission are also common. Clinical signs of EP include poor performance, fever, icterus, abortions, among others, and peracute or acute forms of infection are associated with high mortality in non-endemic areas. EP is a reportable disease and represents an important barrier for the international trade of horses and other equids, causing disruption of international equine sports. Tick control measures, serological and molecular diagnostic methods, and parasiticidal drugs are currently used against EP, while vaccines remain unavailable. Since most acaricides used in equids are non-environmentally friendly and linked to drug resistances, this is considered as an unsustainable approach. Imidocarb dipropionate (ID) and buparvaquone (BPQ) are currently the main drugs used to control the disease. However, while ID has several side and toxic effects and recurrent failures of treatment have been reported, BPQ is less effective in the clearance of T. equi infection and not available in some countries. Thus, novel alternative and effective therapeutics are needed. While current trade regulations require testing equids for EP before exportation, the lack of standardized PCR tests and limitations of the currently recommended serological assays entail a risk of inaccurate diagnosis. Hereby, we propose a combination of standardized PCR-based techniques and improved serological tests to diminish the risks of exporting EP-infected animals making equid international trade safer. In addition, this review discusses, based on scientific evidence, several idiosyncrasies, pitfalls and myths associated with EP, and identifies weaknesses of current methods of control and gaps of research, as initial steps toward developing novel strategies leading to control this disease.

Molecular and immunological studies on Theileria equi and its vector in Egypt

Equine piroplasmosis is not fully understood regarding pathogenicity, prophylaxis, host immune response expression, and specific vectors. Accurately identifying the parasite vector is crucial for developing an effective control plan for a particular infection. This study focused on morphologically identifying two Hyalomma species (H. anatolicum and H. marginatum) and one Rhipicephalus annulatus (R. annulatus) at the species level. The identification process was followed by phylogenetic analysis using the neighbor-joining method based on the cytochrome oxidase subunit 1 (COXI) gene as a specific vector for Theileria equi (T. equi) in horses. T. equi was diagnosed morphologically and molecularly from infected blood samples and crushed tick species using conventional PCR. Subsequently, phylogenetic analysis based on the amplification of the 18 S rRNA gene was conducted. The obtained sequence data were evaluated and registered in GenBank under accession numbers OR064161, OR067911, OR187727, and OR068139, representing the three tick species and the isolated T. equi, respectively. The study demonstrated that T. equi infection leads to immune system suppression by significantly increasing the levels of oxidative stress markers (CAT, GPx, MDA, and SOD) (P ≤ 0.0001), with this elevation being directly proportional to parasitemia levels in infected blood cells. Furthermore, a correlation was observed between parasitemia levels and the expression of immune response infection genes (IFN-gamma, TGF-β1, and IL-1β cytokines) in infected horses compared to non-infected equine. Common macroscopic symptoms indicating T. equi infection in horses include intermittent fever, enlarged lymph nodes (LN), and tick infestation.

The first study of the prevalence and genetic diversity of Theileria equi and Babesia caballi in horses in Russia

Equine piroplasmosis (EP) is a global worldwide infection, which can lead to the death of animals. Despite the causative agents of EP being well studied, there are no data on the distribution and genetic characteristics of EP agents in any region of Russia. In this study, blood samples from 750 horses from Novosibirsk province, Irkutsk province, and Altai region of Russian Siberia were examined for the presence of EP agents. Theileria equi and Babesia caballi were detected in all examined regions, with mean prevalence rates of 60.4% and 7.2%, respectively. The identified pathogens were genetically characterized by the 18S rRNA gene. The determined T. equi sequences were highly conserved and belonged to genotypes A and E, with genotype E being found in 88.6% of genotyped samples. In contrast to T. equi, B. caballi sequences were genetically diverse. Seven sequence variants of B. caballi were identified, and only two of them matched known sequences from the GenBank database. The determined B. caballi sequences belonged to four distinct branches within genotype A. Mixed infections with several variants of B. caballi or with T. equi and B. caballi were common. The conducted phylogenetic analysis based on all available B. caballi sequences of the 18S rRNA gene (> 900 bp) from GenBank and from this study first demonstrated the presence of five monophyletic clusters within genotype A and three clusters within genotype B. Thus, the genetic study of B. caballi from Siberia has significantly expanded the data on the genetic diversity of this pathogen.

Germany-wide citizen science study reveals spread of Babesia canis-infected Dermacentor reticulatus ticks by dogs travelling within the country

The ornate dog tick Dermacentor reticulatus, vector of Babesia canis, has shown a considerable range expansion in several European countries. Previously, only few areas in Germany were recognised as endemic for B. canis, but a marked increase in autochthonous canine babesiosis cases and spread to new areas has been noted recently. To better assess the current risk for dogs, the present study screened 5913 specimens of D. reticulatus from all over Germany, collected in the frame of a Citizen Science study during 2019-2023. Moreover, 343 Dermacentor marginatus ticks were also included. Babesia detection was achieved by quantitative real-time PCR (qPCR). Positive samples were confirmed by sequencing. Moreover, a MGB-probe-based triplex qPCR was established to detect and distinguish between the canine Babesia spp. relevant in Europe, i.e. B. canis, Babesia vogeli and Babesia gibsoni. Overall, B. canis DNA was detected in five D. reticulatus specimens (0.08%). Two of the B. canis-positive ticks originated from areas previously known as endemic for canine babesiosis, namely from the area of Freiburg im Breisgau, federal state of Baden-Wuerttemberg, and from the district St. Wendel, federal state of Saarland. Three further B. canis-positive ticks were detected in districts not yet recognised as endemic, one each in the district of Mansfeld-Suedharz, federal state of Saxony-Anhalt, the district of Ravensburg, federal state of Baden-Wuerttemberg and in the city of Fürth, federal state of Bavaria. However, the tick in Fürth was found on a dog who had returned from a trip to the Breisgau region on the previous day, indicating translocation of the specimen out of this well-known endemic focus. The geographical distribution of the positive samples shows that B. canis is currently spreading in Germany, particularly via dogs travelling within the country, increasing the infection risk throughout the country. Important measures to contain a further spread of the pathogen include comprehensive year-round tick prophylaxis with licensed acaricides, not only to protect the individual pet, but also the entire dog population. Moreover, screening of dogs entering Germany from B. canis-endemic countries is required and any treatment should aim at pathogen elimination by use of appropriate imidocarb dosages.

Molecular and Serological Detection of Vector-Borne Pathogens Responsible for Equine Piroplasmosis in Europe between 2008 and 2021

Equine piroplasmosis (EP) is caused by Theileria (T.) equi and/or Babesia (B.) caballi. The aim was to assess the percentage of positive test results for EP in horses in Europe and to identify risk factors for pathogen contact/infection. This study included results from PCR and competitive enzyme-linked immunosorbent assay testing requested by European veterinarians between 2008 and 2021. Binary bivariate logistic regression was used to analyze risk factors. A total of 4060 horses were included. PCR testing was positive in 9.7% (154/1589), serology for T. equi in 15.2% (393/2591) and for B. caballi in 6.8% (175/2578). The odds of positive serology increased by 6.8% (B. caballi, p = 0.008) and 9.5% (T. equi, p < 0.001) each year. Regionality had a statistically significant impact on PCR (Eastern p = 0.047/OR = 1.605; Southern p = 0.029/OR = 1.451; Central p = 0.007/OR = 0.617) and serological testing for T. equi (Southern p < 0.001/OR = 2.521; Central p < 0.001/OR = 0.537; Northern p = 0.003/OR = 0.462), as well as breeds on seroprevalence of B. caballi (heavy horses: p = 0.016/OR = 2.239) and T. equi (ponies: p = 0.007/OR = 0.340; warmbloods: p = 0.025/OR = 1.602). In conclusion, there was a significant geographical impact on the results of PCR and serology, consistent with known vector habitats. The rising numbers of horses tested serologically positive highlights the importance of surveillance.

Diagnostic performance of a rapid immunochromatographic test for the simultaneous detection of antibodies to Theileria equi and Babesia caballi in horses and donkeys

BACKGROUND

Equine piroplasmosis is caused by two tick-borne protozoan parasites, Theileria equi and Babesia caballi,, which are clinically relevant in susceptible horses, donkeys, and mules. Moreover, equine piroplasmosis significantly constrains international trading and equestrian events. Rapidly diagnosing both parasites in carrier animals is essential for implementing effective control measures. Here, a rapid immunochromatographic test for the simultaneous detection of antibodies to T. equi and B. caballi was evaluated using samples from horses and donkeys collected in Greece, Israel, and Italy. The results were compared with an improved competitive enzyme-linked immunosorbent assay (cELISA) for detecting antibodies to both parasites using the same panel of samples.

METHODS

Blood samples were collected from 255 horses and donkeys. The panel consisted of 129 horses sampled at four locations in northern Greece, 105 donkeys sampled at four locations in Sicily, and 21 horses sampled at two locations in Israel. The rapid test and the cELISA were performed according to the manufacturer's instructions, and the results were subjected to a statistical analysis to determine the sensitivity and specificity of both tests and their association.

RESULTS

The immunochromatographic test provided a result within 15 min and can be performed in the field, detecting both pathogens simultaneously. The overall coincidence rate between the rapid test and the cELISA for detecting antibodies against T. equi was 93% and 92.9% for B. caballi. The rapid test's sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for T. equi were above 91.5%. Sixteen samples were positive for both parasites in the rapid test and eight in the cELISA. Either test had no significant association between T. equi and B. caballi detection. The detection rates of both parasites were significantly higher in Italy than in Greece or Israel and in donkeys than in horses. The agreement for T. equi between the results of both tests was high in Greece (93.8%) and Italy (95.2%) and moderate in Israel (76.2%). For B. caballi, the specificity and NPV of the rapid test were high (94.2% and 98.3%, respectively), although the sensitivity and PPV were moderate (69.2% and 39.1%, respectively) due to the small sample size. However, for B. caballi, the sensitivity was higher with the rapid test.

CONCLUSIONS

The rapid test detected T. equi and B. caballi simultaneously in the field, potentially replacing laborious cELISA testing and is recommended for import/export purposes. The test can also be helpful for the differential diagnosis of clinical cases, since seropositivity may rule out equine piroplasmosis since it does not indicate current or active infection.

Equine Piroplasmosis in Asymptomatic Horses of Western Iran: Comparison of Microscopic Examination and Multiplex PCR

PURPOSE

Piroplasmosis is responsible for anemia, fever, loss of physical activity and even death in equines. In epidemiological studies, accurate diagnostic tests are essential for detecting asymptomatic carriers. This study aimed to investigate the prevalence of infection in asymptomatic horses from Lorestan province, western Iran by developing a multiplex PCR.

METHODS AND RESULTS

Blood samples were examined by microscopy and multiplex PCR targeting the SSU rRNA gene of Theileria equi and Babesia caballi. Out of the total of 165 horses, 19 (11.51%) and 31 (18.78%) cases were positive for piroplasms by microscopy and PCR, respectively. The detection rates of both genera were significantly higher in multiplex PCR compared to microscopy (p < 0.0001). Compared with multiplex PCR, the sensitivities of microscopy for the detection of Babesia were only 28.5%. The prevalence of T. equi infection was significantly higher in summer (p = 0.035). The prevalence of B. caballi was significantly higher in males (p = 0.038).

CONCLUSION

Findings indicate that the multiplex PCR described here is a sensitive technique for the detection of piroplasm DNA in carriers. Furthermore, asymptomatic carriers must be considered as an important source of infection for equids living in this region.

Development and evaluation of specific polymerase chain reaction assays for detecting Theileria equi genotypes

BACKGROUND

Theileria equi causes equine piroplasmosis, an economically significant disease that affects horses and other equids worldwide. Based on 18S ribosomal RNA (18S rRNA sequences), T. equi can be classified into five genotypes: A, B, C, D, and E. These genotypes have implications for disease management and control. However, no conventional polymerase chain reaction (PCR) assays are available to differentiate the genotypes of T. equi. To overcome this limitation, we developed and evaluated PCR assays specific for the detection of each T. equi genotype.

METHODS

A pair of forward and reverse primers, specifically targeting the 18S rRNA sequence of each genotype, was designed. The genotype-specific PCR assays were evaluated for their specificity using plasmids containing inserts of the 18S rRNA sequence of each genotype. Subsequently, the assays were tested on 270 T. equi-positive equine blood DNA samples (92 from donkeys in Sri Lanka and 178 from horses in Paraguay). 18S rRNA sequences derived from the PCR amplicons were analyzed phylogenetically.

RESULTS

Each genotype-specific PCR assay accurately targeted the intended genotype, and did not produce any amplicons when 18S rRNA from other T. equi genotypes or genomic DNA of Babesia caballi or uninfected horse blood was used as the template. Previous studies employing PCR sequencing methods identified T. equi genotypes C and D in the Sri Lankan samples, and genotypes A and C in the Paraguayan samples. In contrast, our PCR assay demonstrated exceptional sensitivity by detecting four genotypes (A, C, D, and E) in the Sri Lankan samples and all five genotypes in the Paraguayan samples. All the Sri Lankan samples and 93.3% of the Paraguayan samples tested positive for at least one genotype, further emphasizing the sensitivity of our assays. The PCR assays also had the ability to detect co-infections, where multiple genotypes in various combinations were detected in 90.2% and 22.5% of the Sri Lankan and Paraguayan samples, respectively. Furthermore, the sequences obtained from PCR amplicons clustered in the respective phylogenetic clades for each genotype, validating the specificity of our genotype-specific PCR assays.

CONCLUSIONS

The genotype-specific PCR assays developed in the present study are reliable tools for the differential detection of T. equi genotypes.

Impact of Equine and Camel Piroplasmosis in Egypt: How Much Do We Know about the Current Situation?

Piroplasmosis is a global tick-borne disease caused by hemoprotozoan parasites, which causes high morbidity and substantial economic losses in farm animals. Equine and camel piroplasmosis causes significant losses worldwide and in Egypt. The multifactorial effects and overall impact of equine and camel piroplasmosis in Egypt remain poorly characterized. However, several Babesia and Theileria spp. as well as potential tick vectors affecting these two species have been identified in the country. Equine and camel piroplasmosis has been reported by all governates in the country. Thus, in this work, we intend to provide a broad depiction of the current approaches used for diagnosis and control and the impact of piroplasmosis on the equine and camel industries in Egypt. We also identified current gaps in knowledge that might help develop future research efforts towards improved intervention and control of equine and camel piroplasmosis. It is important to develop specific diagnostic tools suitable for the early and chronic diagnosis of this disease. Altogether, the current situation warrants the development of large-scale epidemiological studies in order to obtain an accurate estimate for equine and camel piroplasmosis to secure the highly needed food resources in the country.

Clinical and epidemiological aspects of the infection by Babesia, Theileria and Trypanosoma species in horses from northeastern Colombia

Piroplasmosis and trypanosomiasis are debilitating diseases of great economic impact on the equine industry of Latin America. Considering the lack of studies in the northeastern part of Colombia, this study aimed to determine the epidemiological, clinical and genetic features associated with infection of the Babesia, Theileria, and Trypanosoma species in horses from this geographical area. Two hundred and eighty horses from the Arauca, Meta, and Santander departments were molecularly analyzed for infection with Babesia caballi, Theileria equi, Trypanosoma evansi, and Trypanosoma vivax. Furthermore, clinical, epidemiological and entomological analyses were performed on the data sets. Molecular analysis showed 25.7% and 3.9% prevalence for T. equi and T. evansi, respectively, without positive animals for B. caballi and T. vivax. There were no differences in the prevalence of T. equi between departments, whereas T. evansi was detected exclusively in Santander. A total of 633 ticks were collected from 72 horses across the three departments, with 84.7% corresponding to Dermacentor nitens, 10.9% to Amblyomma cajennense (sensu lato) (s.l). and 4.4% to Rhipicephalus microplus. For T. equi, genetic analyses showed that Colombian isolates belong to genotype C of species, along with sequences of Brazil and Mexico. Epidemiological analysis revealed a significant association between tick infestation and lack of vector control with molecular infection of T. equi, whereas clinical analysis revealed a significant reduction in packed cell volume, red blood cells, and mean corpuscular volume in positive animals to this pathogen. Furthermore, molecular infection by T. evansi was associated with epidemiological characteristics in the Santander department. In conclusion, our analysis revealed a moderate infection rate by T. equi of genotype C in horses from northeastern Colombia, which affects their clinical conditions. Control of ticks and treatment of symptomatic animals should be considered to reduce the economic impact associated with these infections in the equine industry.

Haemato-biochemical characterization of equine piroplasmosis asymptomatic carriers and seropositive, real-time PCR negative horses

Equine piroplasmosis (EP) is caused by Theileria equi and Babesia caballi, transmitted by tick vectors. Horses can suffer an acute, subacute, and chronic forms of the disease, with clinical signs such as poor performance, fever, pale mucosal membranes, and jaundice. The diagnosis of EP subclinical cases is complex due to the sensitivity of real-time PCR and the limited parasite load in some carriers, making it challenging to differentiate them from seropositive, PCR negative (S+PCR-) individuals. This study aimed to describe haematological and biochemical changes in asymptomatic EP carriers, EP S+PCR- horses and control horses (EP seronegative and PCR negative). It also investigated potential haemato-biochemical markers to aid in distinguishing true EP carriers alongside molecular and serological tests. A comprehensive haematology and biochemistry profile was conducted on 410 sera and EDTA blood samples, comprising 130 EP positives by real-time PCR and competitive ELISA (cELISA) (carriers), 130 EP negatives by real-time PCR but positive to cELISA (S+PCR-) and 150 EP negative horses to real-time PCR and c-ELISA (controls). Our study confirmed that a haematological and biochemistry profile could help to differentiate between EP carriers/S+PCR- from healthy horses. Carriers and S+PCR- horses showed significant increases in the white blood cell count (WBC), high total proteins (TP) and total globulins (GLOB) concentration, and liver function markers compared to controls. Additionally, the evaluation of uric acid (UA) suggested oxidative stress in carrier horses. However, no useful haemato-biochemical diagnostic markers were identified to aid the challenging differentiation of EP carriers and S+PCR- horses, highlighting the need for improvement in molecular/serological diagnosis for these horses.

Development of a Real-Time Quantitative PCR Based on a TaqMan-MGB Probe for the Rapid Detection of Theileria haneyi

Equine piroplasmosis (EP) is a parasitic disease caused by Theileria equi (T. equi), Babesia caballi (B. caballi) and Theileria haneyi (T. haneyi). This disease is considered to be reportable by the World Organization for Animal Health (WOAH). Real-time quantitative PCR (qPCR) is regarded as a straightforward, rapid and sensitive diagnostic method to detect pathogens. However, qPCR has not been employed in the various epidemiological investigations of T. haneyi. In this study, we developed a new qPCR method to detect T. haneyi based on the chr1sco (chromosome 1 single-copy open reading frame (ORF)) gene, which has no detectable orthologs in T. equi or B. caballi. A TaqMan MGB probe was used in the development of the qPCR assay. A plasmid containing the chr1sco gene was constructed and used to establish the standard curves. The novel qPCR technique demonstrated great specificity for detecting additional frequent equine infectious pathogens and sensitivity for detecting diluted standard plasmids. This qPCR was further validated by comparison with an optimized nested PCR (nPCR) assay in the analysis of 96 clinical samples. The agreement between the nPCR assay and the established qPCR assay was 85.42%. The newly established method could contribute to the accurate diagnosis of T. haneyi infections in horses.

Chromosome-level genome assembly of Babesia caballi reveals diversity of multigene families among Babesia species

BACKGROUND

Babesia caballi is an intraerythrocytic parasite from the phylum Apicomplexa, capable of infecting equids and causing equine piroplasmosis. However, since there is limited genome information available on B. caballi, molecular mechanisms involved in host specificity and pathogenicity of this species have not been fully elucidated yet.

RESULTS

Genomic DNA from a B. caballi subclone was purified and sequenced using both Illumina and Nanopore technologies. The resulting assembled sequence consisted of nine contigs with a size of 12.9 Mbp, rendering a total of 5,910 protein-coding genes. The phylogenetic tree of Apicomplexan species was reconstructed using 263 orthologous genes. We identified 481 ves1-like genes and named "ves1c". In contrast, expansion of the major facilitator superfamily (mfs) observed in closely related B. bigemina and B. ovata species was not found in B. caballi. A set of repetitive units containing an open reading frame with a size of 297 bp was also identified.

CONCLUSIONS

We present a chromosome-level genome assembly of B. caballi. Our genomic data may contribute to estimating gene expansion events involving multigene families and exploring the evolution of species from this genus.

Comparison of Seroprevalence and Identification of Risk Factors for Theileria equi in Horses From Vector-Free and Infested Areas in Southern Brazil

The apicomplexan hemoprotozoan Theileria equi is a tick-borne pathogen that causes disease in equids, and together with Babesia caballi, causes equine piroplasmosis (EP). Many ticks are associated with EP around the world, and in South America three species may be related: Dermacentor nitens, Amblyomma sculptum, and Rhipicephalus microplus, as they are commonly found in horses. Among the species cited above, only R. microplus is found in Rio Grande do Sul state, Southern Brazil. In addition, this state has the only area legally free of R. microplus in Brazil. This study aimed to compare the seroprevalence for T. equi on farms located in a tick-free area (23 farms, 215 horses) and a tick-infested (25 farms, 141 horses) adjacent areas, as well as to identify potential risk factors for exposure to T. equi. Blood was collected from 356 horses from both areas, and later an indirect enzyme-linked immunosorbent assay was performed to detect anti-T. equi antibodies. Besides the blood collection, questionnaires and interviews were conducted in an attempt to identify potential risk factors. The R. microplus-free zone had 6% seropositive horses against 70% in the tick-infested zone. Previous observation of ticks on horses of the herd increased four times the odds of a horse to be seropositive for T. equi, and by three times if ticks were observed on cattle which share paddocks with horses on the farm. The results showed a large difference in T. equi seroprevalence between tick-infested and free areas, and also emphasized the relevance of R. microplus in the epidemiology of T. equi. The study also reveals the potential of the establishment of a T. equi-free zone for horse breeding in Southern Brazil.

Occurrence and genotyping of Theileria equi in dogs and associated ticks in Egypt

Theileriosis is a tick-borne protozoal disease caused by a piroplasm of the genus Theileria. Hard ticks are obligate hematophagous ectoparasites that serve as vectors of Theileria spp. Studies of the presence of theileriosis in Egyptian dogs and associated ticks are scarce. This study was conducted to detect and identify Theileria spp. in dogs and Rhipicephalus sanguineus ticks and to monitor the epidemiological data of this disease. The prevalence rates of Theileria equi infection were 12.02%, 0.73%, 2.93%, and 1.83% by microscopic examination of dog blood, tick hemolymph, tick midgut, and tick salivary smears, respectively. Conversely, the T. equi prevalence in dog blood and associated ticks assessed by PCR was 25.81% and 10.42%, respectively. Epidemiological data about Theileria infection revealed a significant difference in the infection between different seasons and different dog breeds (p value <0.05), whereas host, sex, and age of dogs had no significant effect on the infection. Sequencing of PCR products showed that all PCR positive samples were infected with T. equi. Transmission electron microscopy (TEM) described the different stages of Theileria in the midgut and salivary gland of infected ticks. The current study confirmed that T. equi is not specific to equine hosts, and confirmed that dogs are a susceptible host to T. equi.

Prevalence and genetic diversity of Theileria equi from horses in Xinjiang Uygur Autonomous region, China

Theileria equi is a tick-borne intracellular apicomplexan protozoan parasite that causes equine theileriosis (ET). ET is an economically important disease with a worldwide distribution that significantly impacts international horse movement. Horses are an essential part of the economy in Xinjiang which is home to ∼10% of all the horses in China. However, there is very limited information on the prevalence and genetic complexity of T. equi in this region. Blood samples from 302 horses were collected from May to September 2021 in Ili, Xinjiang, and subjected to PCR examination for the presence of T. equi. In addition, a Bayesian latent class model was employed to estimate the true prevalence of T. equi, and a phylogenetic analysis was carried out based on the 18S rRNA gene of T. equi isolates. Seventy-two horses (23.8%) were PCR positive. After accounting for the imperfect PCR test using a Bayesian latent class model, the estimated true prevalence differed considerably between age groups, being 10.8% (95%CrI: 5.8% - 17.9%) in ≤ 3-year-old horses and 35.7% (95%CrI: 28.1% - 44.5%) in horses that were > 3 year-old. All T. equi isolates had their 18S rRNA gene (430bp) sequenced and analyzed in order to identify whether there were multiple genotypes of T. equi in the Xinjiang horse population. All of the 18S rRNA genes clustered into one phylogenetic group, clade E, which is thus probably the dominant genotype of T. equi in Xinjiang, China. To summarize, we monitored the prevalence of T. equi in horses of Xinjiang, China, with a focus on the association between age and the occurrence of T. equi by Bayesian modelling, accompanied by the genotyping of T. equi isolates. Obtaining the information on genotypes and age structure is significant in monitoring the spread of T. equi and studying the factors responsible for the distribution.

A U.S. Isolate of Theileria orientalis Ikeda Is Not Transstadially Transmitted to Cattle by Rhipicephalus microplus

Theileria orientalis Ikeda has caused an epidemic of bovine anemia and abortion across several U.S. states. This apicomplexan hemoparasite is transmitted by Haemaphysalis longicornis ticks; however, it is unknown if other North American ticks are competent vectors. Since the disease movement is largely determined by the host tick range(s), the prediction of the T. orientalis spread among U.S. cattle populations requires determination of additional competent tick vectors. Although Rhipicephalus microplus has mostly been eradicated from the U.S., outbreaks in populations occur frequently, and the U.S. remains at risk for reintroduction. Since R. microplus is a vector of Theileria equi and T. orientalis DNA has been detected in R. microplus, the goal of this study was to determine whether R. microplus is a competent vector of T. orientalis. Larval R. microplus were applied to a splenectomized, T. orientalis Ikeda-infected calf for parasite acquisition, removed as molted adults, and applied to two T. orientalis naïve, splenectomized calves for transmission. After 60 days, the naïve calves remained negative for T. orientalis by PCR and cytology. Additionally, T. orientalis was not detected in the salivary glands or larval progeny of acquisition-fed adults. These data suggest that R. microplus is not a competent vector of the U.S. T. orientalis Ikeda isolate.

Analysis of the tick communities associated to domestic mammals in rural areas of the Yungas montane forest from Argentina

The aim of this work was to describe the tick community associated to domestic mammals in rural areas from the Yungas lower montane forest of Argentina. The circulation of tick-borne pathogens was also analyzed. Samples of ticks parasitizing cattle, horses, sheep and dogs were carried out in different seasons, and questing ticks were collected from vegetation and analyzed to detect the presence of Rickettsia, Ehrlichia, Borrelia and Babesia by a battery of different PCRs. The structure of the tick communities was analyzed through the Chao1 species richness estimator, the Shannon-Wiener index and the Horn index of community similarity. Eight tick species were collected in the study area: Amblyomma sculptum, Rhipicephalus microplus, Amblyomma hadanii, Dermacentor nitens, Amblyomma ovale, Haemaphysalis juxtakochi, Ixodes pararicinus and Rhipicephalus sanguineus sensu stricto. However, A. sculptum was by far the dominant species in the tick assemblages analyzed, and this was reflected in the low diversity values obtained. Dermacentor nitens, A. sculptum and R. microplus were the three species associated to horses. The predominance of A. sculptum was also observed in the tick samples obtained from dogs, even on two tick species, namely A. ovale and R. sanguineus s.s., which have dogs as the principal domestic host. Rhipicephalus microplus and A. sculptum were the most abundant ticks on cattle, while few specimens of I. pararicinus, A. hadanii and D. nitens were found on bovines. Dermacentor nitens ticks were found to be infected with B. caballi, which indicate the circulation of this pathogen of horses in the Yungas area. The detection of a strain of Borrelia sp. belonging to the B. burgdorferi s.l. complex in I. pararicinus is consistent with previous findings made in Argentina, but the public health relevance of this vector-microorganism association is far from being similar to that occurs in the northern hemisphere because there are practically no records of these tick species parasitizing humans in South America. The tick community of rural areas of the Yungas lower montane forest is composed by species which are potential vectors of pathogenic microorganism with veterinary and public health importance, circulating in a human-wildlife-livestock interface.

PCR detection of Theileria equi and Babesia caballi in apparently healthy horses in Paraguay

Equine piroplasmosis (EP) is a tick-borne disease caused by Theileria equi and Babesia caballi in equids, including horses. EP has a global distribution and often leads to a significant socioeconomic impact on the equine industry. Infected animals remain as carriers and become a source of infection for tick vectors, thereby posing an immense challenge in the disease management. Therefore, detection of these carriers is crucial to assess the risk of transmission and to implement appropriate control measures in endemic countries. Paraguay is a tropical country where various tick-borne diseases are common among livestock; however, the status of EP remains unknown in this country. Because the tick vectors capable of transmitting T. equi and B. caballi are endemic in Paraguay, we hypothesised that Paraguayan horses are infected with these parasite species. To test our hypothesis, we prepared blood DNA samples from a total of 545 apparently healthy horses in 16 of the 17 departments of Paraguay and analysed them with specific PCR assays to detect T. equi and B. caballi. The PCR results showed that 178 (32.7%) and 8 (1.5%) of the horses were infected with T. equi and B. caballi, respectively. Among the infected horses, two (0.4%) were infected with both parasite species. Our analyses further indicated that the positive rates of T. equi infection did not differ between horse breeds, males and females, or age groups. We also found that haematological parameters were the same between the non-infected animals and animals with single infections. By contrast, the two horses co-infected with T. equi and B. caballi had haemoglobin and haematocrit values lower than the normal ranges. In conclusion, the present study demonstrated that Paraguayan horses are infected with T. equi and B. caballi and that the rate of T. equi infection is higher than that of B. caballi. Our findings highlight the need to add EP to the list of differential diagnoses when anaemic horses are presented to equine clinics in Paraguay.

An Update of Evidence for Pathogen Transmission by Ticks of the Genus Hyalomma

Current and likely future changes in the geographic distribution of ticks belonging to the genus Hyalomma are of concern, as these ticks are believed to be vectors of many pathogens responsible for human and animal diseases. However, we have observed that for many pathogens there are no vector competence experiments, and that the level of evidence provided by the scientific literature is often not sufficient to validate the transmission of a specific pathogen by a specific Hyalomma species. We therefore carried out a bibliographical study to collate the validation evidence for the transmission of parasitic, viral, or bacterial pathogens by Hyalomma spp. ticks. Our results show that there are very few validated cases of pathogen transmission by Hyalomma tick species.

A risk assessment of equine piroplasmosis entry, exposure and consequences in the UK

BACKGROUND

Equine piroplasmosis (EP) is currently not endemic in the UK, despite a lack of formal surveillance and the presence of carrier horses in the equine population. Pathogen establishment would have significant welfare and economic impacts on the national equine industry, but the disease is often overlooked by UK practitioners.

OBJECTIVES

To assess the risk of disease entry, exposure and consequences to the UK equine population.

STUDY DESIGN

Qualitative risk assessment.

METHODS

A qualitative risk assessment was constructed utilising the current World Organisation for Animal Health (OIE) published framework for importation risk assessment, assessing the key areas of disease entry, exposure and consequences to the UK equine population.

RESULTS

The overall risk of EP entry to the UK via importation of infected equidae with acute disease is very low but considered medium with subclinical carrier animals. Entry via importation of ticks or the importation of blood is considered very low. The risk of EP exposure to susceptible equidae in the UK is considered low by the infection routes of tick-bites, contaminated needles and contaminated blood, but very high via transplacental transfer. However, the consequences of EP endemic establishment are considered of high significance to the UK equine industry.

MAIN LIMITATIONS

A lack of available numerical data for events and variables in disease import risk meant a qualitative assessment was the most practical method for this scenario.

CONCLUSIONS

This risk assessment highlights that EP positive animals are able to enter and are currently present in the UK, and that conditions do exist that could allow forward transmission of the disease. It has highlighted a gap in existing policy where the UK falls behind OIE guidelines and has suggested steps to correct this discrepancy and improve national biosecurity.

Differential Expression of Immune Genes in the Rhipicephalus microplus Gut in Response to Theileria equi Infection

Rhipicephalus microplus is the only tick species known to serve as a biological vector of Theileria equi for horses and other equids in Brazil. The protozoan T. equi is one of the causal agents of equine piroplasmosis, a major threat in horse breeding systems. Vector competence is closely linked to the pathogens' ability to evade tick defense mechanisms. However, knowledge of tick immune response against infections by hemoparasites of the Theileria genus is scarce. In the present study, the expression of genes involved in immune signaling pathways of R. microplus adults' guts when challenged with a high or low parasitic load of T. equi was evaluated. This research demonstrates divergences in the immune gene expression pattern linked to T. equi infection in R. microplus since the Toll, IMD, and JNK signaling pathways were transcriptionally repressed in the guts of adult ticks infected with T. equi. Moreover, the results showed that different infectious doses of T. equi induce differential gene expression of key components of immune signaling cascades in R. microplus gut, suggesting a link between the intensity of infection and the activation of tick immunity response. The present study adds knowledge to elucidate the gut immune signaling response of R. microplus to T. equi infection. In addition, the generated data can serve as a basis for further investigations to develop strategies for controlling and preventing equine piroplasmosis.

Comparison of direct and indirect methods to maximise the detection of Babesia caballi and Theileria equi infections in Central Southern Italy

Equine piroplasmosis is a disease of equids, caused by tick-borne apicomplexan protozoan pathogens Babesia caballi and Theileria equi, which, according to the World Organisation for Animal Health (OIE), can be diagnosed by enzyme-linked immunosorbent assay (ELISA), immunofluorescent antibody test (IFAT) and polymerase chain reaction (PCR). The present study was conducted to evaluate and compare the assays available for the diagnosis of equine piroplasmosis. Data employed were obtained from 1300 blood samples collected between 2012-2014 from asymptomatic and symptomatic equines (horses and donkeys) of central-southern regions of Italy and analyzed by ELISA, IFAT, PCR (one commercial and one from literature) and blood smear microscopic examination. Statistical differences of the proportions of positivity for each parasite and group (asymptomatic and symptomatic) among the methods were verified by the z test to identify the most sensitive. The concordance between each pair of methods - for each parasite and within the groups - and trends in detection of suspect samples of four hypothetical diagnostic algorithms using serological and biomolecular assays were evaluated to identify the most suitable laboratory diagnostic workflow. The results of this study highlighted a lower capacity to detect suspect samples of commercial ELISA for B. caballi in all groups when compared to biomolecular methods and IFAT; and of the commercial PCRs in asymptomatic animals, identifying a PCR from literature and IFAT as the best choice for a combined diagnosis. For T. equi, IFAT detected more suspect samples than ELISA, even if the latter showed good performance and some samples were positive only by the ELISA and PCR, indicating that their simultaneous employment is still advantageous. Host-parasite interaction, amino-acid/genetic diversity and differences in detection limits among the assays could be among the reasons in explaining the present results. In view of further studies, ELISA should be used in combination with PCR, that should regularly be included in the laboratory diagnosis to maximise the detection of early infections and support the evaluation of pharmacological treatment.

Theileria equi in the horses of Iran: Molecular detection, genetic diversity, and hematological findings

In all equids worldwide, Theileria equi and Babesia caballi are believed to be two important erythrocytic protozoa that cause equine piroplasmosis. In addition, it was recently discovered that Theileria haneyi is another potential equine piroplasmosis (EP) agent. Ixodid ticks are the major vectors of these parasites. Equine piroplasmosis is of international importance and affects enormously the equine industry. In this study, for the first time, molecular prevalence and genetic diversity of piroplasma parasites (T. equi and B. caballi) in horses from Fars province (south of Iran) were determined. Also, hematological alterations of naturally infected horses were analyzed. PCR positive horses showed anemia, thrombocytopenia, leukocytosis with a left shift of neutrophilia, and monocytosis. PCR results revealed that, from 133 blood samples of horses, 40 samples were positive (30.07%). The occurrence of T. equi in this area (30.07%) was more than the national average prevalence of T. equi (24.11%), but B. caballi prevalence in study area (0%) was less than the average of previous studies in Iran (5.47%). Our findings revealed that the T. equi was widespread in Fars province of Iran. PCR products of 18S rDNA and EMA-1 genes of T. equi strains were sequenced successfully. All 18S rDNA sequences collected in this experiment revealed 100% similarity together. According to the phylogenetic tree constructed using the 18S rDNA gene, Iranian T. equi is clustered with strains from Cuba (KY111762, KY111761) and USA (CP001669, JX177672). So, this could be concluded that T. equi studied in this research, and those strains are initiated from a common T. equi ancestor at an unknown time ago. Also, the phylogenetic tree based on EMA-1 gene demonstrated a genetically diverse population of Iranian T. equi strains (10 different genotypes). As EMA-1 is one of the most immunogenic antigens in this parasite, such variability could be a concern about the efficacy of T. equi vaccines. Finally, more studies on equine piroplasmosis in the provinces of the southern region of Iran are recommended to create a better vision of disease in this region.

The Prevalence of Pathogens among Ticks Collected from Livestock in Kazakhstan

Ticks carry and transmit a wide variety of pathogens (bacteria, viruses and protozoa) that pose a threat to humans and animals worldwide. The purpose of this work was to study ticks collected in different regions of Kazakhstan for the carriage of various pathogens. The collected ticks were examined by PCR for the carriage of various pathogens. A total of 3341 tick samples parasitizing three animal species (cattle, sheep and horses) were collected at eight regions of Kazakhstan. Eight tick species were found infesting animals: Dermacentor marginatus (28.08%), Hyalomma asiaticum (21.28%), Hyalomma anatolicum (17.18%), Dermacentor reticulatus (2.01%), Ixodes ricinus (3.35%), Ixodes persulcatus (0.33%), Hyalomma scupense (12.87%) and Hyalomma marginatum (14.90%). Ticks collected from livestock animals were examined for the pathogen spectrum of transmissible infections to determine the degree of their infection. Four pathogen DNAs (lumpy skin disease virus (LSDV), Coxiella burnetti, Teileria annulata, and Babesia caballi) were detected by PCR in Dermacentor marginatus, Hyalomma asiaticum, Hyalomma scupense, Hyalomma anatolicum. The infection of ticks Dermacentor marginatus and Hyalomma asiaticum collected on cattle in the West Kazakhstan region with LSDV was 14.28% and 5.71%, respectively. Coxiella burnetti was found in the ticks Dermacentor marginatus (31.91%) in the Turkestan region and Hyalomma anatolicum (52.63%) in the Zhambyl region. Theileria annulata was found in ticks Hyalomma scupense (7.32%) and Dermacentor marginatus (6.10%) from cattle in the Turkestan region. Babesia caballi was isolated only from the species Hyalomma scupense (17.14%) in the Turkestan region. There were no PCR-positive tick samples collected from sheep. RNA/DNAs of tick-borne encephalitis virus (TBEV), African swine fever virus (ASFV), Hantavirus hemorrhagic fever with renal syndrome (HFRS), and chlamydia pathogens were not found in ticks. The new data give a better understanding of the epidemiology of tick-borne pathogens and the possibility of the emergence of tick-borne animal diseases in Kazakhstan.

Low seroprevalence of equine piroplasmosis in horses exported from the Netherlands between 2015 and 2021

Equine piroplasmosis (EP) is a tick-borne disease affecting horses, donkeys, mules and zebras, caused by the intracellular apicomplexan protozoa Babesia caballi and Theileria equi. The geographical distribution of EP is closely related to the distribution of its vector tick species belonging to the genera of Dermacentor, Rhipicephalus and Hyalomma. Since the discovery of Dermacentor reticulatus ticks in 2007 and the first reported autochthonous cases in the South of the Netherlands in 2012, no data on the (sero)prevalence of EP in horses in the Netherlands have been reported and it remains unclear whether B. caballi and T. equi have been able to establish themselves in the Netherlands. This study aims to give an update on the current status of EP in horses in the Netherlands using data from serological tests performed in the context of export and screening of 12,881 horses from 2015 through 2020. Horses were categorized as “Dutch,” “Foreign,” or “Unknown” based on microchip number. The overall seroprevalence of EP in Dutch horses was found to be 0.5% (95% exact CI [0.4–0.7]), compared to 1.9% (95% exact CI [1.3–2.6]) in horses in the category “Foreign” and 1.7% (95% exact CI [1.2–2.3]) in horses in the category “Unknown.” In addition, the seroprevalence per country in the category “Foreign” ranged from 0% (0.95% exact CI [0–2.8]) for Ireland to 6.0% (0.95% exact CI [3.5–9.3]) for Spain. In light of the reports on the seroprevalence during the outbreak of autochthonous EP reported in 2012 and on seroprevalences of EP in other countries in Northwestern Europe, the seroprevalence of EP in horses exported from the Netherlands is very low. However, the higher seroprevalence of EP in horses from abroad warrants the need for the monitoring of EP, as tick vectors are present in the Netherlands and the import of horses from endemic areas increases the chances of EP becoming more prevalent in the Netherlands.

Seroprevalence of Anti-Theileria equi Antibodies in Horses from Three Geographically Distinct Areas of Romania

Equine piroplasmosis (EP) is an endemic tick-borne disease found in most countries around the world. It affects all species of Equidae, and it is caused by Theileria equi, Babesia caballi and T. haneyi. The research herein is the second study on the prevalence of piroplasms in Romania conducted in the past two decades. The aim of this study was to assess the seroprevalence of anti-Theileria equi antibodies and the geographical distribution of this disease in the southwest, west, and northwest regions of Romania in order to obtain a more thorough understanding of the parasitological status of horses in this country. This study included 522 apparently healthy, mixed-breed horses from three different counties. The serum samples were analysed using the cELISA Theileria equi Antibody Test Kit. The overall seroprevalence rate was 12.84%. From the total number of positive horses, 13.96% were females and 11.21% were males. Based on the distribution of positive cases into age groups, the following values were obtained: 0−60 months: 16.26%, 60−180 months: 10.03%, and >180 months: 15.83%. There was no statistically significant difference between samples, based on age or gender. The positivity percentage in the localities included in the study ranged from 8.33 to 100%. In the population under study, the seroprevalence rate was high, indicating a possible exposure risk in this area of Romania, which could have severe effects on equids in the case of clinical manifestations of the disease. EP represents a serious threat for equine health in Romania; therefore, close and continuous monitoring of the situation is required.

Molecular investigation of Babesia caballi in horses from the state of Rio de Janeiro, Brazil: Epidemiological aspects associated with the infection

The epidemiological aspects of Babesia caballi infection were evaluated in 516 horse samples from Rio de Janeiro, Brazil. The presence and infestation level of ticks on horses, breed conditions, and animal management were evaluated on each farm through an epidemiological questionnaire. The gene that codes for rhoptry-associated protein-1 (RAP-1) of B. caballi was amplified by nested PCR (nPCR). Among the horses sampled, 17.2% (n = 89/516) presented B. caballi DNA. The characterized samples showed 99-100% similarity with other isolates of B. caballi based on the RAP-1 gene, available in GenBank. In the final logistic regression model, the variables associated with B. caballi infection in horses were as follows: age below two years (OR = 3.33; IC = 1.7-6.5), farms located in low altitudes (OR = 3.52; IC = 1.7-7.3) and Dermacentor nitens infestation (OR = 1.91; IC = 1.1-3.4). Furthermore, a high level of D. nitens infestation in horses was also a factor associated with positivity for B. caballi (OR = 2.11; IC = 1.25-3.54). In summary, young horses bred in low altitude regions characterized with high temperatures, and infested by D. nitens, mainly with a higher level of infestation, are more likely to be infected by B. caballi. This epidemiological study provides statical evidence that the D. nitens tick play a role as the biological vector of B. caballi in the studied region.

Dynamics of Theileria equi Infection in Rhipicephalus (Boophilus) microplus during the Parasitic Phase in a Chronically Infected Horse

Experimental studies have demonstrated that Rhipicephalus (Boophilus) microplus transmits Theileria equi to horses. However, the degree and dynamics of this protozoan infection in the vector’s organism have not been fully elucidated. Therefore, this study aimed to evaluate the infection rate and parasitic load of T. equi in R. (B.) microplus, the infection dynamics in this arthropod during experimental infestation in a horse chronically infected with T. equi, and to evaluate the trans-stadial and intrastadial transmission competence of T. equi by R. (B.) microplus. The experimental infestation period of R. (B.) microplus on the horse was 33 days, but males were found on the animal up to 60 days post-infestation. After the fifth day post-infestation, ticks and equine blood were collected every two days. Whole ticks from the same developmental stage collected in the same day were pooled. Adult ticks were dissected to extract salivary glands and gut. DNA extraction was performed for all the samples, and they were then submitted to qPCRs for T. equi diagnosis. Freshly molted nymphs collected as larvae in the horse and freshly molted males and females collected as nymphs in the horse showed equal to or greater than 75% positivity for T. equi, indicating a strong possibility of trans-stadial transmission. The longest permanence of the male ticks on the horse associated with the high positivity rate of this type of sample for T. equi indicate that the male may play a role in the intrastadial transmission of T. equi to infection-free horses. The salivary glands displayed 77.78% positivity for T. equi and presented a higher infection rate at the end of the experimental period (100% from 29 to 33 days post-infection). This study shows that R. (B.) microplus has high T. equi infection rates and that the infection rate and parasitic load increased over the experimental period. These findings confirm the importance of chronically infected horses with T. equi as a source of infection for R. (B.) microplus.

Serological and molecular detection of Babesia caballi and Theileria equi in Mexico: A prospective study

Equine piroplasmosis is a disease of horses, mules and donkeys, caused by the hemoprotozoans Babesia caballi and Theileria equi and transmitted by ticks of tropical and subtropical regions. Because the clinical signs are not specific, the diagnosis of equine piroplasmosis is difficult. In Mexico, where the environmental factors are conducive to the persistence of these pathogens, there is a lack of molecular studies to evaluate the occurrence of both parasites in horses. In the present study, matching serum and whole blood samples were obtained from 269 horses residing in 24 locations with tropical or subtropical climate and the presence of ticks. Testing of serum samples by ELISA demonstrated 55.7% seroprevalence of B. caballi and 68.4% prevalence of antibodies to T. equi. Blood samples analyzed with nPCR test were 7.8% positive to B. caballi and 78.8% positive to T. equi, while a duplex qPCR showed 15.24% positive samples to B. caballi and 59.11% to T. equi. From these results, 27 samples were sequenced for T. equi and 13 for B. caballi, confirming the presence of both horse parasites that cause equine piroplasmosis and suggesting that they are widespread in Mexico. This is the first study confirming the presence of B. caballi and T. equi in Mexico using both serological and molecular diagnostic methods. This study shows a high incidence of exposure to the etiological agents of equine piroplasmosis in horses in the studied areas.

The distribution of Dermacentor reticulatus in the Czech Republic re-assessed: citizen science approach to understanding the current distribution of the Babesia canis vector

Background

The range of the ornate dog tick Dermacentorreticulatus is rapidly expanding in Europe. This tick species is the vector of canine babesiosis, caused by Babesiacanis, and also plays a role in the transmission of Theileriaequi and Babesiacaballi in equids.

Methods

The geographic range of D.reticulatus in the Czech Republic was re-assessed, and an up-to-date distribution map is presented based on material and data obtained during a nationwide citizen science campaign. Received and flagged individuals of D.reticulatus were also analysed for the presence of B.canis DNA.

Results

In striking contrast to historical records, D.reticulatus was found in all regions of the Czech Republic, with most reports coming from the southeast and northwest of the country. Between February 2018 and June 2021, the project team received 558 photo reports of ticks and 250 packages containing ticks. Of the former, 71.1% were identified as Dermacentor sp. with the remainder identified as Ixodes sp., Haemaphysalis sp., Argas sp. or Hyalomma sp. The majority of specimens in the subset of ticks that were received (N = 610) were D.reticulatus (N = 568, 93.7%), followed by Ixodesricinus and Hyalomma spp. A total of 783 adult D.reticulatus, either received (568) or collected by flagging (215), were tested for the presence of B.canis DNA using species-specific nested PCR targeting part of the 18S rRNA gene; B.canis DNA was demonstrated in 22 samples (2.81%).

Conclusions

The continuous spread of D.reticulatus in the Czech Republic was documented in this study. In addition, DNA of B.canis was also detected in a number of ticks, suggesting the establishment of B.canis in the Czech Republic. These results suggest that veterinarians need to consider the possibility of canine babesiosis even in dogs without a history of travel.

Graphical Abstract

First detection of Theileria equi in free-roaming donkeys (Equus africanus asinus) in Sri Lanka

Equine piroplasmosis (EP) is a tick-borne disease caused by Theileria equi and Babesia caballi in equids, including horses, donkeys, zebras, and mules. It is globally endemic with significant economic impact on the equine industry. Infected animals may serve as carriers, and they may be a source of infection for ticks, thereby posing a great challenge for disease management. Sri Lanka is a tropical country, where infections by various tick-borne parasites are common among livestock animals. However, infections by T. equi and B. caballi remain unstudied in Sri Lanka. Therefore, in the present study, we conducted an epidemiological survey to investigate the presence of T. equi and B. caballi in apparently healthy free-roaming donkeys. Blood samples were randomly taken from 111 donkeys in Mannar (n = 100) and Kilinochchi (n = 11) districts in Sri Lanka. Thin blood smears were prepared from the blood samples and subjected to microscopic examination. Additionally, blood DNA samples were prepared and screened for T. equi and B. caballi infections using species-specific PCR assays. Our results showed that 64 (57.7%) and 95 (85.6%) of the donkeys were positive for T. equi by microscopy and PCR, respectively. However, all samples were negative for B. caballi. Phylogenetic analysis of the T. equi 18S rRNA sequences detected two distinct genotypes, namely C and D. To our knowledge, this is the first report of T. equi in Sri Lanka and of genotype C in donkeys. The present study highlights the importance of monitoring the shrinking donkey population in Sri Lanka owing to EP caused by T. equi.

Effects of Competitive ELISA-Positive Results of Piroplasmosis on the Performance of Endurance Horses

Simple Summary

Equine piroplasmosis (EP) is a common infectious disease in southern Europe. To better understand the impact and influence of EP on the performance of endurance horses, we collected blood samples from national elite horses during different endurance competitions. The horses were tested against piroplasmosis, and several blood parameters related to performance were also evaluated. It seems that horses without clinical signs of piroplasmosis can participate without performance impairment in competitions of up to 80 km. Although it is recommended that longer distance competitions should be further evaluated, this is the first step for decision-making by organizers and participants in this sport.

Abstract

Endurance is an increasingly popular equestrian sport. However, in southern Europe, there is a high prevalence of horses that are asymptomatic carriers of equine piroplasmosis (EP), a tick-borne disease that could affect their performance. This study aimed to evaluate the impact and influence of EP on the performance of endurance horses. Blood samples were collected from 40 horses in Extremadura, Spain, before and after a race, in different national elite horse endurance competitions. Hematological and biochemical parameters and EP seroprevalence were analysed by competitive enzyme-linked immunosorbent assay. The global seroprevalence of EP was 70%, with 27 horses testing positive for Theileria equi (67.5%) and three (7.5%) for Babesia caballi, with two of these horses (5%) positive for both. Approximately 82.5% of the horses (33 of 40) completed the competition, with no influence on performance or position achieved in those with subclinical parasitosis. There were also no significant differences in hematological or biochemical values between seropositive and seronegative horses. The data suggest that horses without clinical signs of EP can participate without performance impairment in competitions of up to 80 km. Although it is recommended that longer distance competitions should be further evaluated, this is the first step for decision-making by organizers and participants in this sport.

Molecular characterization of some equine vector-borne diseases and associated arthropods in Egypt

Equine vector-borne diseases (EVBDs) are emerging and re-emerging diseases, and most of them are zoonotic. This study aimed to investigate EVBDs in equines and associated arthropods (ticks and flies) from Egypt using molecular analyses, in addition to a preliminary characterization of associated ticks and flies by the matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) and molecular techniques. In this study, 335 blood samples were obtained from equines that appeared to be in good health (320 horses and 15 donkeys) in Cairo and Beni Suef provinces, Egypt. From the same animals, 166 arthropods (105 sucking flies and 61 ticks) were collected. Ticks and flies were preliminary characterized by the MALDI-TOF and molecular tools. Quantitative PCR (qPCR) and standard PCR coupled with sequencing were performed on the DNA of equines, ticks, and flies to screen multiple pathogens. The MALDI-TOF and molecular characterization of arthropods revealed that louse fly (Hippobosca equina) and cattle tick (Rhipicephalus annulatus) infesting equines. Anaplasma platys-like (1.6%), Anaplasma marginale (1.6%), Candidatus Ehrlichia rustica (6.6%), a new Ehrlichia sp. (4.9%), and Borrelia theileri (3.3%) were identified in R. annulatus. Anaplasma sp. and Borrelia sp. DNAs were only detected in H. equina by qPCR. A. marginale, Anaplasma ovis, and Theileria ovis recorded the same low infection rate (0.6%) in donkeys, while horses were found to be infected with Theileria equi and a new Theileria sp. Africa with recorded prevalence rates of 1.2% and 2.7%, respectively. In conclusion, different pathogens were first detected such as A. platys-like, Candidatus E. rustica, and a new Ehrlichia sp. in R. annulatus; A. marginale, A. ovis, and T. ovis in donkeys; and a new Theileria sp. "Africa" in horses.

Spatial and Temporal Circulation of Babesia caballi and Theileria equi in France Based on Seven Years of Serological Data

Caused by two blood parasites, Babesia caballi and Theileria equi, equine piroplasmosis is a tick-borne disease that poses major health and economic issues for the equine industry. Our objective was to gain insight into the spatio-temporal variations of parasite circulation in France, where the disease is known to be enzootic, but has been the subject of few studies. Seroprevalence was assessed for each parasite thanks to 16,127 equine sera obtained between 1997 and 2003 from all over France and analysed through complement fixation tests. Results indicated that 13.2% (5-27% depending on the region) of horses were seropositive for T. equi and 9.5% (3-25%) for B. caballi. Regardless of the year, horses from the southern regions of France were the most affected by B. caballi or T. equi infection, while the proportion of horses having antibodies against T. equi increased over time. These results highlight the heterogeneity of the circulation of both piroplasms, which may be linked with ecological diversity and vector distribution. Our data provide baseline information regarding the sero-epidemiology of B. caballi and T. equi infection in horses in France, making it now possible to select regions for future studies on risk factors, and design and implement effective targeted measures against equine piroplasms.

Molecular assessment of Theileria equi and Babesia caballi prevalence in horses and ticks on horses in southeastern France

Equine piroplasmosis (EP) is a tick-borne disease caused by Babesia caballi and Theileria equi that is potentially emerging in non-endemic countries. We conducted a descriptive study to investigate EP prevalence and spatial distribution in an endemic region: the Camargue and the Plain of La Crau in France. In spring 2015 and 2016, we carried out sampling at stables (total n = 46) with a history of horses presenting chronic fever or weight loss. Overall, we collected blood from 632 horses, which were also inspected for ticks; these horses had been housed in the target stables for at least 1 year. We obtained 585 ticks from these horses and described land use around the stables. Real-time PCR was employed to assess T. equi and B. caballi prevalence in the horses and in the ticks found on the horses. For the horses, T. equi and B. caballi prevalence was 68.6% and 6.3%, respectively. For the ticks found on the horses, prevalence was 28.8% for T. equi and 0.85% for B. caballi. The most common tick species were, in order of frequency, Rhipicephalus bursa, R. sanguineus sl., Hyalomma marginatum, Haemaphysalis punctata, and Dermacentor sp. Horses bearing Rhipicephalus ticks occurred in wetter zones, closer to agricultural areas, permanent crops, and ditches, as well as in drier zones, in the more northern countryside. Compared to horses bearing R. bursa, horses bearing R. sanguineus sl. more frequently occurred near the Rhone River. Prevalence of T. equi in the ticks was as follows: Hyalomma marginatum (43%), Dermacentor sp. (40%), R. bursa (33%), R. sanguineus sl. (19%), and Haemaphysalis punctata (17%). In contrast, B. caballi only occurred in Dermacentor sp. (20%) and R. bursa (1%).

How many cattle can be infected by Trypanosoma vivax by reusing the same needle and syringe, and what is the viability time of this protozoan in injectable veterinary products?

It was investigated how many cattle become infected with Trypanosoma vivax by subcutaneous (SC), intramuscular (IM) and intravenous (IV) routes, using the same syringe and needle from an animal with acute T. vivax infection. Besides, the T. vivax viability in 109 injectable veterinary drugs (antibiotics, antiparasitics, reproductive hormones, vitamin complex and derivatives, vaccines, anaesthetics, anti-inflammatory/antipyretics, antitoxics). In the field assay, four groups were performed: T01, T02 and T03 animals that received saline solution with the same syringe and needle contaminated with T. vivax via SC, IM and IV routes, respectively, and T04 control animals that received only saline solution with the same syringe and needle IV. In the laboratory, drugs had their pH measured and T. vivax viability verified. The number of cattle infected with T. vivax via SC (3/20) was lower (P ≤ 0.05) compared to via IM (9/20), which was lower (P ≤ 0.05) compared to IV (15/20). The solution pH did not influence T. vivax viability. In 44% (48/109) of the products, T. vivax remained viable regardless of time, stooding out that in 100% of oxytocins the protozoan was verified, at some evaluation times. The mean of T. vivax quantified in foot-and-mouth and brucellosis vaccines and in doramectin-based products were higher (P ≤ 0.05) than found in blood + saline solution.