Prevalence of piroplasmosis in equines in the Colombian province of Cordoba

Sero-molecular survey and risk factors of equine piroplasmosis in horses in Spain

BACKGROUND

Theileria equi and Babesia caballi cause equine piroplasmosis (EP), one of the most important tick-borne diseases of horses due to its high negative impact to the equine industry. Although infections with these parasites have been reported for decades in Spain, epidemiological studies have only been carried out in certain regions.

OBJECTIVES

To determine the (sero)prevalence of these parasites in asymptomatic horses nationwide in Spain and to identify potential individual and environmental factors associated with seropositivity to EP.

STUDY DESIGN

Sample size was calculated according to the horses registered in Spain in 2013 and by autonomous community using a random stratified sampling. A questionnaire was used to collect data on factors associated with EP seropositivity.

METHODS

Serological (cELISA and complement fixation test) and molecular (real-time PCR) analyses were carried out in 740 horses. Risk factors were identified computing two independent logistic regression models with the collated data.

RESULTS

Antibodies against EP were detected in 42.9% (95% CI 39.4-46.5) of horses, whereas 30.3% (95% CI 27.0-33.6) were EP positive by PCR. A substantial strength of agreement (k = 0.721) was estimated between serological tests. Exposure to T. equi was significantly higher than to B. caballi and the highest (sero)prevalence was detected in the northern communities. Increasing horse age, presence of ticks and contact with cows were factors related to EP seropositivity in the horses, whereas tetanus vaccination and fairs attendance were associated with lower seropositivity.

CONCLUSIONS

Almost half of the horses residing in Spain had antibodies against EP or circulating parasitaemia. Appropriate prevention measures and implementation of a EP surveillance programme should be considered in order to reduce and control the infection.

Garrapatas duras (Acari: Ixodidae) de Colombia, una revisión a su conocimiento en el país

Las garrapatas son artrópodos de gran impacto sobre la economía pecuaria y la salud humana debido a las pérdidas generadas en la producción, y a su capacidad de transmitir microorganismos. Pese a la evidencia de circulación de una gran diversidad de garrapatas en Colombia, no se cuenta con compilaciones actualizadas de la variedad de especies presentes, por lo cual los autores presentan una revisión de literatura sobre las garrapatas de la familia Ixodidae reportadas en Colombia incluyendo su distribución geográfica, sus hospederos y los microorganismos reportados en aquellas especies registradas en este país. En la recopilación se evidenció la presencia en Colombia de diferentes especies de garrapatas de los géneros Amblyomma, Ixodes, Haemaphysalis, Rhipicephalus y Dermacentor. El género con mayor variedad fue Amblyomma con 29 especies, seguido de Ixodes con 11 especies, y de los géneros Dermacentor, Haemaphysalis y Rhipicephalus se reportaron dos especies para cada uno. Las especies se distribuyeron en la mayoría de los departamentos de Colombia y en una amplia diversidad de hospederos entre los cuales se incluyen animales domésticos, sinantrópicos y silvestres. Adicionalmente se encontró que algunas garrapatas reportadas podrían jugar un papel como vectores potenciales de diversos microorganismos que pueden afectar a la salud pública y veterinaria. Esperamos que este trabajo sea un aporte para apoyar la investigación en garrapatas y el estudio de los agentes transmitidos por estas en Colombia.

Seroprevalence of Theileria equi and Babesia caballi in horses in Spain

Equine piroplasmoses are enzootic parasitic diseases distributed worldwide with high incidence in tropical and subtropical regions. In Spain, there is insufficient epidemiological data about equine piroplasmoses. The main aim of the present study was therefore to estimate the prevalence of Theileria equi and Babesia caballi in five regions and obtain information about the risk factors. This study was conducted in the central and south-western regions of Spain, using indirect fluorescence antibody testing (IFAT) in 3,100 sera samples from apparently healthy horses of different ages, breeds, coat colours, genders and geographical locations. The overall seroprevalence was 52%, consisting of 44% seropositive for T. equi and 21% for B. caballi. There was a significant association between age (p < 0.0001), breed (p < 0.004), geographical location (p < 0.0001) and the seroprevalence, but neither the coat colour nor the gender was significantly associated with prevalence. In addition, it was proved that most of the geographic areas showed a moderate to high prevalence. The statistical κ value was used to compare the results obtained by the IFAT and the competitive enzyme-linked immunosorbent assay (cELISA) utilised to test some samples (n = 108) and showed a higher concordance for T. equi (κ = 0.68) than for B. caballi (κ = 0.22). Consequently, this revealed the importance of developing an appropriate technique to detect each haemoparasite.

Serological prevalence of Babesia caballi and Theileria equi in horses of Lara State, Venezuela

The main objective of this study was to demonstrate the occurrence of equine piroplasmosis (EP) in horses of Lara State, Venezuela, and to correlate it with the factors host's sex and age in order to know the epidemiology of this disease at the Venezuelan Centroccidental Region. Antibody levels to Babesia caballi and Theileria equi were assessed in 360 equine serum samples, collected from 9 municipalities of Lara State, using an ELISA technique with recombinant antigens and monoclonal antibodies (Mabs). Antibodies to B. caballi were found in 254 horses (70.6%), whereas 181 animals (50.3%) were detected as seropositives to T. equi. In addition, 128 samples (35.56%) were seropositives to both hemoparasites. There were no significant differences between the seropositivity to B. caballi and T. equi with the factors sex and age of the horses. These results show that Lara State is an enzootic area for equine piroplasmosis, and are a contribution to a partial knowledge of the dynamic of this disease in Venezuela.

Epidemiological aspects of Babesia equi in horses in Minas Gerais, Brazil

The prevalence of Babesia equi in two climatic regions of Minas Gerais state was determined using the indirect fluorescent antibody test (IFAT) with blood samples obtained from horses in two slaughterhouses. Of 399 samples, 241 (60.4%) showed a positive reaction. Anti-B. equi antibody was detected in every county studied, the prevalence being 59.7% for horses in the area where the temperature rises above 18 degrees C in winter and 61.4% in the area where it remains below 18 degrees C, indicating that climatic variation has no substantial effect on the prevalence of the infection in Brazil. Blood samples collected from all 95 horses on a ranch in the state of Minas Gerais, Brazil, on which clinical babesiosis had never been reported, were subjected to the IFAT Anti-B. equi antibodies were detected in horses of all ages, but with a significantly lower prevalence in animals less than 6 months old.

Seroepidemiologic studies on Babesia equi and Babesia caballi infections in Brazil

Horses from six stud farms representing the most frequent types of horse breeding in Brazil were tested for Babesia antibodies by the IFA test. The farms are located at the tropic of Capricorn at an altitude of 472-715 m where temperatures below 0 degrees C may occur. Horses of conventional stud farms were infested with Dermacentor nitens, Amblyomma cajennense, and Boophilus microplus. Infestation with Bo. microplus was associated with direct or indirect contact of horses with cattle, and was not detected at professional stud farms. At one large professional stud farm, only D. nitens was observed. Prevalence of Babesia equi correlated positively (p<0.001) with contact of pastured horses to cattle (67.1% versus 17.5%). The IFA test was validated using sera from 92 non-infected horses and from 18 ponies infected experimentally with the USDA strains of B. equi or B. caballi or with the Brazilian isolates from the study area. Differences in test results obtained using antigens from USDA strains or Brazilian isolates were not significant. The specificity was 100% except for the IFA test using Brazilian antigen of B. caballi (98%). The sensitivity was 100% except for the IFA test using the USDA antigen of B. caballi. Accuracy of the tests ranged from 98 to 100%, and predictive values from 99 to 100%. Only 59% (132/224) of sera, positive by the IFA test for B. equi, tested positive by CF test, and 45% (232/515) of sera, positive by the IFA test for B. caballi, also tested positive by CF test. In all, 740 field sera from 140 horses, including 63 mares and their foals, were tested. Prevalence and incidences of B. caballi infections were significantly higher than those of B. equi infections: 49.2% (31/63) of the mares were infected with B. equi, but 79.4% (50/63) with B. caballi; 36% (18/50) of the foals became infected with B. equi within 12 months, but 100% (50/50) with B. caballi within 10 months. Maternal antibodies against B. equi and B. caballi in foals were 44 (22/50) and 68% (34/50), respectively. Titers persisted for 1-5 months for B. equi and 1-4 months for B. caballi.

Seroprevalence of Babesia equi among horses in Israel using competitive inhibition ELISA and IFA assays

Sera from 361 horses were tested by indirect immunofluorescence antibody test (IFA) and by competitive inhibition ELISA (cELISA), to detect antibodies to Babesia equi. The concordance between the assays was 95.7%. Application of a cutoff based on a calculated percent inhibition of < 20% gave a total of 22 discrepant results, while only 8 sera negative by the cELISA were found positive by the IFA when a cutoff of > 20% inhibition was used. Approximately one-third of all the horses tested were found serologically positive to B. equi, with more horses testing positive from northern Israel. Among horses raised with access to pasture there was a significant difference in the percentage of seropositive reactors (76.6% in the north and 20.1% in the central region), compared with horses without access to pasture (14.3 and 10.3%, respectively). Nineteen percent of stallions were found to be positive, which was significantly less than the proportions of seropositive mares and geldings: 38 and 42%, respectively. No significant association was found between the mean age of horses and seroreactivity to B. equi.

Epidemiological aspects of equine babesioses in a herd of horses in Brazil

Epidemiological studies of Babesia equi and B. caballi were undertaken in a herd of 120 pastured horses in Rio de Janeiro, Brazil. The area where the horses were held was shown to be highly endemic for both Babesia spp., i.e. the prevalence of B. equi antibodies in horses aged 6 months or older ranged from 90.6% to 100% as determined by the immunofluorescence antibody (IFA) test, and the prevalence of B. caballi antibodies as determined by Western blot ranged from 59.4% to 65.5%. From the herd, 20 foals and their dams were selected to estimate the degree of tick infestation and the foals were bled at monthly intervals to determine the incidence of antibodies to B. equi and B. caballi. The incidence of B. equi was 100% by about 127 days of age as determined by IFA of B. caballi was 100% by about 150 days of age as determined by Western blot. Tick infestation of the horses estimated by using a semiquantitative key ranged from at least five ticks on every horse to more than 100 ticks on many horses throughout the year. Except for three Boophilus microplus female ticks, they were identified as Amblyomma cajennense and Anocentor nitens. A. cajennense had one generation per year, whereas An. nitens had three. Kinetes of B. caballi were detected in the haemolymph of two of 68 An. nitens female ticks and in the ovary and eggs of one of these, suggesting that this tick is a significant vector of B. caballi.(ABSTRACT TRUNCATED AT 250 WORDS)