Development of a pooled antigen for use in the macroscopic slide agglutination test (MSAT) to detect Sejroe serogroup exposure in cattle

Guedes, Israel Barbosa; Souza, Gisele Oliveira de; Castro, Juliana Fernandes de Paula; Filho, Antônio Francisco de Souza; Rocha, Katarine de Souza; Gomes, Maria Érika Teixeira; Moraes, Carla Cristina Guimarães de; Heinemann, Marcos Bryan

doi:10.1016/j.mimet.2019.105737

Cited by 9 publications

(7 citation statements)

References 25 publications

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“…In other investigations conducted in semiarid regions, Sejroe (58.17%) was the most prevalent serogroup, followed by Icterohaemorrhagiae (17.32%) and Australis (4.58%) [ 7 ], as well as Sejroe (36.8%), Hebdomadis (26.3%), Australis (10.5%), Djasiman (10.5%), Ballum (5.3%) and Pomona (5.3%) [ 35 ]. Surveys of different regions of Brazil have demonstrated that regardless of the biome involved, Sejroe was most prevalent: 50.68% average prevalence in northeastern region [ 7 , 35 , 36 , 37 ]; 72.65% in northern region [ 38 , 39 ]; 30.3% in central-western region [ 40 ]; 47.01% in southeastern region [ 41 , 42 , 43 , 44 ]; and 48.56% in southern region [ 45 , 46 ]. The plurality of types of Leptospira suggests that contact with other animals exists, but there is the possibility that cattle without signs and symptoms of Leptospira spp.…”

Section: Discussionmentioning

confidence: 99%

Bovine Leptospirosis in Caatinga Biome, Brazil: New Insights into Diagnosis and Epidemiology

et al. 2023

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Bovine leptospirosis causes economic losses and raises public health concerns. It is possible that there are peculiarities in the epidemiology of leptospirosis in regions with a semiarid climate, such as the Caatinga biome in Brazil, where the climate is hot and dry, and the etiological agent require alternative routes of transmission. This study aimed to close knowledge gaps to the diagnosis and epidemiology of Leptospira spp. infection in cows from the Caatinga biome, Brazil. Samples of the blood, urinary tract (urine, bladder and kidney) and reproductive tract (vaginal fluid, uterus, uterine tube, ovary and placenta) were collected from 42 slaughtered cows. Diagnostic tests included were the microscopic agglutination test (MAT), polymerase chain reaction (PCR) and bacterial isolation. Anti-Leptospira spp. antibodies were found in 27 (64.3%) of the animals analyzed using MAT at a 1:50 dilution (cut-off 50), while 31 (73.8%) animals had at least one organ/fluid where the presence of Leptospira spp. DNA was identified, and 29 animals (69%) were positive at bacteriological culture. The highest sensitivity values for MAT were obtained at the cut-off point of 50. In conclusion, even under hot and dry climate conditions, it is possible that Leptospira spp. can spread through alternative routes such as venereal transmission; moreover, a cut-off of 50 is recommended for the serological diagnosis of cattle from the Caatinga biome.

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Section: Discussionmentioning

confidence: 99%

Bovine Leptospirosis in Caatinga Biome, Brazil: New Insights into Diagnosis and Epidemiology

et al. 2023

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“…The MSAT suggests the possible infective serovars using an antigen in suspension, which may include a pool of up to three inactivated serovars. The MSAT can be used for the diagnosis of leptospirosis in both humans [ 24 , 25 ] and animals [ 26 – 28 ]. Other serological assays, such as the enzyme-linked immunosorbent assay (ELISA) [ 29 , 30 ] can also be used to detect infection.…”

Section: Discussionmentioning

confidence: 99%

A machine learning model of microscopic agglutination test for diagnosis of leptospirosis

et al. 2021

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Leptospirosis is a zoonosis caused by the pathogenic bacterium Leptospira. The Microscopic Agglutination Test (MAT) is widely used as the gold standard for diagnosis of leptospirosis. In this method, diluted patient serum is mixed with serotype-determined Leptospires, and the presence or absence of aggregation is determined under a dark-field microscope to calculate the antibody titer. Problems of the current MAT method are 1) a requirement of examining many specimens per sample, and 2) a need of distinguishing contaminants from true aggregates to accurately identify positivity. Therefore, increasing efficiency and accuracy are the key to refine MAT. It is possible to achieve efficiency and standardize accuracy at the same time by automating the decision-making process. In this study, we built an automatic identification algorithm of MAT using a machine learning method to determine agglutination within microscopic images. The machine learned the features from 316 positive and 230 negative MAT images created with sera of Leptospira-infected (positive) and non-infected (negative) hamsters, respectively. In addition to the acquired original images, wavelet-transformed images were also considered as features. We utilized a support vector machine (SVM) as a proposed decision method. We validated the trained SVMs with 210 positive and 154 negative images. When the features were obtained from original or wavelet-transformed images, all negative images were misjudged as positive, and the classification performance was very low with sensitivity of 1 and specificity of 0. In contrast, when the histograms of wavelet coefficients were used as features, the performance was greatly improved with sensitivity of 0.99 and specificity of 0.99. We confirmed that the current algorithm judges the positive or negative of agglutinations in MAT images and gives the further possibility of automatizing MAT procedure.

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“…An interesting result was that L. santarosai was not detected in the buffalo samples, differing from what is reported for cattle in other regions of the country, such as the southeast, where this species is one of the most prevalent (8,24,35). The dimensions and heterogeneity of the with climatic conditions in the Amazon make this region unique and different from other parts of the country, which is reflected in the etiological agenthost relationships and may account for the situation found in cattle from the Amazon region, where L. santarosai may not be involved in leptospirosis in these animals (9,36). Regarding buffalo, more work is needed to evaluate the participation of L. santarosai and others species in buffalo leptospirosis.…”

Section: Discussionmentioning

confidence: 99%

Identification of Pathogenic Leptospira Species in the Urogenital Tract of Water Buffaloes (Bubalus bubalis) From the Amazon River Delta Region, Brazil

et al. 2020

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In the current context of deforestation and fire in the Amazon, buffaloes could be a cost-effective and sustainable alternative for cattle production in the region, as they can convert low-quality foods and be raised in floodplain areas. However, little is known about the reproductive diseases that affect these animals; thus, the purpose of this study was to perform the molecular characterization of Leptospira spp. in the urogenital tract of water buffaloes (Bubalus bubalis) raised in the Amazon River Delta region in Brazil. Samples were collected from 114 kidneys, 204 ovaries, and 160 uterine swabs of slaughtered buffaloes in the Macapá microregion of Amapá State (Brazil) and were subjected to PCR to detect bacterial DNA. Positive amplicons were sequenced to identify Leptospira species. Among the total samples, 11/473 were PCR positive (2.3%), including 10 kidney samples and one uterine swab sample. DNA sequencing identified two pathogenic species from the kidney samples: L. interrogans, accounting for 60.0% (6/10) of these samples, and L. borgpetersenii, accounting for 20.0% (2/10), while 20.0% (2/10) were identified only at the genus level. The bacterium in the uterine swab sample was identified as L. interrogans with genetic proximity to strains belonging to the serovar Hardjo. This is the first report of leptospires species identified in buffaloes from the Amazon River Delta region and revealed that these animals may be carriers of different pathogenic Leptospira species, similar to bovines, including showing genital colonization.

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Development of a pooled antigen for use in the macroscopic slide agglutination test (MSAT) to detect Sejroe serogroup exposure in cattle

Cited by 9 publications

References 25 publications

Bovine Leptospirosis in Caatinga Biome, Brazil: New Insights into Diagnosis and Epidemiology

Bovine Leptospirosis in Caatinga Biome, Brazil: New Insights into Diagnosis and Epidemiology

A machine learning model of microscopic agglutination test for diagnosis of leptospirosis

Identification of Pathogenic Leptospira Species in the Urogenital Tract of Water Buffaloes (Bubalus bubalis) From the Amazon River Delta Region, Brazil

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