Abstract: Equine brucellosis significantly impacts the health and functionality of horses, leading to complications such as bursitis infection, septic tenosynovitis, septic arthritis, and non-specific lameness resulting from joint infections. In the present study, we used the Rose Bengal plate agglutination test (RBPT), serum agglutination test (SAT), and the 2-mercaptoethanol (2-ME) assays to find equine brucellosis. From June 2018 to September 2022, 876 blood samples were randomly taken from apparently healthy racing horses in certain parts of Iran, such as Kerman, Isfahan, Tehran, Qom, and Kurdistan. DNA extraction was carried out directly on all 63 serum samples identified as seropositive through RBPT. An additional 30 seronegative serum samples were also randomly chosen for study. Bacterial culture was also done on milk, blood, and vaginal swabs taken from seropositive horses.The bacteria that were found in the samples were then put through Bruce-ladder PCR. Our results indicated that 63 (7.1%), 21 (2.3%), and 2 (0.2%) of horses were seropositive using RBPT, SAT, and 2-ME, respectively. Also, none of the 30 DNA-extracted serum samples from seronegative horses tested positive for Brucella DNA, while 44.5% (28/63) of the DNA samples from seropositive horses yielded positive results for Brucella DNA. Out of the seropositive samples, 26 had DNA from Brucella abortus and 2 had DNA from Brucella melitensis. Also, B. melitensis biovar 1 was found in two milk samples from mares in the provinces of Kerman and Isfahan. It was identified using classical biotyping, and molecular assays. It was seen that some of healthy racing horses in some parts of Iran had antibodies against Brucella. The bacteriology and PCR methodologies provide a more comprehensive and reliable means of identifying Brucella spp. infections in horse, especially when the RBPT test came back positive. This underscores the imperative for employing molecular, bacterial, and serological methods in the diagnosis and monitoring of this zoonotic infection. Additionally, this finding suggests that Brucella is being transmitted to equine hosts as a result of its presence in ruminants. The mechanism of transmission may involve interactions between infected ruminants and susceptible equines. This discovery is significant as it underscores the potential cross-species transmission of Brucella and highlights the importance of understanding and managing the spread of the pathogen in both ruminant and equine populations.
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This study investigates the prevalence and transmission of Brucella bacteria in healthy racing horses from various regions in Iran, using a combination of serological, bacteriological, and molecular methods.
Methodology
In this research, the scientists collected 876 blood samples from apparently healthy racing horses in Iran’s various provinces such as Kerman, Isfahan, Tehran, Qom, and Kurdistan between June 2018 and September 2022.
To detect the presence of equine brucellosis, three different tests were utilized: the Rose Bengal plate agglutination test (RBPT), serum agglutination test (SAT), and the 2-mercaptoethanol (2-ME) assays. These tests help in identifying the antibodies against Brucella bacteria in horses’ blood.
63 serum samples that tested positive for Brucella antibodies through RBPT were chosen for further testing through DNA extraction. Similarly, 30 seronegative serum samples were also randomly selected for the study.
Bacterial culture was performed on milk, blood, and vaginal swabs taken from seropositive horses. The bacteria found in these samples were then subjected to Bruce-ladder PCR analysis for further identification.
Findings from the study
The results showed that out of 876 horses, 63 (7.1%) were identified as seropositive for Brucella antibodies through RBPT, 21 (2.3%) through SAT, and 2 (0.2%) through 2-ME test.
Out of the 63 seropositive blood samples, DNA extraction indicated that 44.5% (28 samples) tested positive for Brucella DNA. None of the 30 seronegative samples showed presence of Brucella DNA.
Among the seropositive samples, 26 had DNA from Brucella abortus species, and 2 had DNA from Brucella melitensis species.
Moreover, B. melitensis biovar 1, a specific subtype of Brucella melitensis, was detected in two milk samples from mares in the provinces of Kerman and Isfahan, using both classical biotyping and molecular assays.
Implications of the Findings
The outcomes from this research suggest that the combination of bacterial, serological, and molecular tests can provide a more comprehensive and reliable method for detecting Brucella spp. infections in horses, especially when the RBPT test result is positive.
The study also revealed that even healthy racing horses in some regions of Iran carry antibodies against Brucella, indicating exposure to the bacteria.
The results suggest potential cross-species transmission of Brucella, as the presence of the bacteria in equine hosts could be due to interactions with infected ruminants. This finding highlights the importance of controlling the spread of Brucella across both ruminant and equine populations.
Cite This Article
APA
Amini M, Alamian S, Talebhemmat M, Dadar M.
(2024).
Equine brucellosis in Iran: serological, bacteriological and molecular analysis.
Vet Res Commun.
https://doi.org/10.1007/s11259-024-10332-0
Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education and Extension Organization (AREEO), Kerman, Iran.
Alamian, Saeed
Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
Talebhemmat, Mahdokht
Reference laboratory of veterinary organization, Kerman, Iran.
Dadar, Maryam
Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran. dadar.m77@gmail.com.
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