Detection of Brucella spp. in dogs at Pantanal wetlands

Molecular and serological investigation of Brucella species in kennel and farm dogs in Iran

INTRODUCTION

Brucellosis is still a significant emerging threat to public health, as it can infect humans, wild, domestic animals, and livestock. Hence, the current study aims to determine the frequency of canine brucellosis (CB), its relationship with clinical findings and reproductive disorders in kennel and farm dogs, and its importance on public health.

MATERIALS AND METHODS

From January 2022 to December 2023, a total of 150 blood samples were taken from 100 adult dogs in breeding kennels and 50 shepherd dogs in breeding farms in Kerman, Iran. Rose Bengal test (RBT) and Wright tests were used for the primary screening of Brucella abortus (B. abortus) and Brucella melitensis (B. melitensis) species, and conventional IS711-based PCR and real-time polymerase chain reaction (RT-PCR) were performed to determine the Brucella genus and species in all samples.

FINDINGS

In kennel dogs, 34 % (34/100) had a history of breeding disorders, and 30 % (30/100) were RBT-positive. Moreover, B. canis and B. abortus species were detected in kennel dogs. Among farm dogs, 16 % (8/50) had a history of breeding disorders, and 28 % (14/50) were RBT positive. Additionally, B. canis, B. abortus, and B. melitensis species were detected in farm dogs. Feeding with unpasteurized milk was significantly related to a positive RBT in kennel dogs (p = 0.009), and there was a significant correlation between breeding disorders and seropositivity in kennel (p = 0.045) and farm dogs (p = 0.03).

CONCLUSION

The current study represents a significant advancement in understanding CB in Iran by the first molecular detection of B. canis, revealing B. melitensis and B. abortus as important pathogens in kennel and farm dogs and highlighting the public health significance of disease in Iran.

A first insight into seropositivity and risk factors for Brucella spp. and Coxiella burnetii in free-roaming dogs in Ecuador

Brucellosis and Q fever are two bacterial zoonoses caused by Brucella spp. and Coxiella burnetii, respectively. Dogs are reservoirs of these pathogens and play an important role in their spread. In this research, we determined the seroprevalence of antibodies against Brucella spp. and C. burnetii in free-roaming dogs from Ecuador and conducted a statistical analysis based on geographical variables. Serum samples were collected from 397 free-roaming dogs between November 2018 and May 2019 and analyzed with commercial ELISA tests for Brucella spp. and Q fever. An overall seroprevalence of 2.8 % (CI: 95 %, 0.0-6.2 %) and 1.8 % (CI: 95 %, 0.0-5.6 %) was found for Brucella spp. and C. burnetii, respectively. No statistical differences in seroprevalence values were found between geographical regions in Ecuador or between dogs from rural or urban settings, except for the association of C. burnetii infection with the Coastal Region. This is the first study of this kind in Ecuador and points out the need for a One Health approach for control and surveillance of zoonotic diseases like brucellosis and Q fever including feral and stray dogs as reservoirs to spread those pathogens to cattle, humans, or wildlife.

Detection of Brucella S19 Vaccine Strain DNA in Domestic and Wild Ungulates from Brazilian Pantanal

The Pantanal region, the largest floodplain in the world, has a huge biodiversity and is an important livestock center. Bovine brucellosis has been reported in the region over the last three decades, posing implications for cattle industry as well as for the maintenance of biodiversity. We aimed to investigate the presence of B. abortus S19 vaccine strain DNA in unvaccinated domestic and wild ungulates from the Brazilian Pantanal. Fifty-two heifers, 63 ovine, 24 domestic pigs, 28 feral pigs, and three Pampas deer were sampled. Brucella spp. was detected through bcsp31 PCR of blood samples in 45.3% (77/170) of the sampled animals, of which 36.4% (28/77) showed positivity in ery PCR corresponding to B. abortus S19 strain. Feral pigs presented the highest occurrence of positive samples in bcsp31 PCR (75%), followed by ovine (47.6%), domestic pigs (41.7%), and unvaccinated heifers (30.8%). We did not observe positivity in Pampas deer. Our results strongly suggest that vaccination against bovine brucellosis may promote spill-over of B. abortus S19 strain in the Pantanal region. Moreover, our data indicate that wild strains of Brucella circulates in the Pantanal Biome.

Brucellosis in the Brazilian Pantanal wetland: threat to animal production and wildlife conservation

This review was performed to gather knowledge about brucellosis in livestock and wildlife in the Brazilian Pantanal, a biome with a huge biodiversity and extensive livestock production. Following the preferred reporting items for narrative review guidelines and using the terms "Brucella" and "Pantanal," we explored the PubMed, SciELO, Jstor, Science Direct, and Scholar Google databases. Information on host species, diagnostic test, number of positive animals, and positivity rates were acquired. Articles dating from 1998 to 2022 registered 14 studies including cattle, dogs, and the following wildlife species: Ozotoceros bezoarticus, Sus scrofa, Tayassu peccari, Nasua nasua, Cerdocyon thous, Panthera onca, Dasypus novemcintus, Cabassous unicinctus, Euphractus sexcinctus, Priodontes maximus, Myrmecophaga tridactyla and Hydrochoerus hydrochaeris. Brucella occurrence in cattle was demonstrated through the serological confirmatory test 2-mercaptoetanol. Molecular diagnosis detected Brucella abortus in dogs, smooth Brucella in O. beoarticus, and Brucella spp. in T. peccari. Cattle may have a pivotal importance in maintenance and spreading of Brucella spp. due to their high population density, environmental contamination from abortion of infected cows, and eventual excretion of B. abortus S19 strain from vaccinated heifers. The occurrence of Brucella spp. in O. bezoarticus and T. peccari represent a risk for wildlife conservation. These data indicate that Brucella spp. are enzootic in the Pantanal wetland, sustained by a reservoir system including domestic and wild mammals. Due to marked seasonality and large populations of wildlife species sharing same environments with livestock, brucellosis acquires great complexity in Pantanal and, therefore, must be analyzed considering both animal production and conservation.

Accuracy of molecular diagnostic methods for the detection of bovine brucellosis: A systematic review and meta-analysis

Background and Aim:

Bovine brucellosis is a disease of global socio-economic importance caused by Brucella abortus. Diagnosis is mainly based on bacterial culture and serology. However, these methods often lack sensitivity and specificity. A range of molecular diagnostic methods has been developed to address these challenges. Therefore, this study aims to investigate the diagnostic accuracy of molecular tools, in comparison to gold standard bacterial isolation and serological assays for the diagnosis of bovine brucellosis.

Materials and Methods:

The systematic review and meta-analysis were conducted based on analyses of peer-reviewed journal articles published between January 1, 1990, and June 6, 2020, in the PubMed, Science Direct, Scopus, and Springer Link databases. Data were extracted from studies reporting the use of molecular diagnostic methods for the detection of B. abortus infections in animals according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The quality of included journal articles was assessed using the quality assessment of diagnostic-accuracy studies assessment tool and meta-analysis was carried out using Review Manager.

Results:

From a total of 177 studies, only 26 articles met the inclusion criteria based on PRISMA guidelines. Data from 35 complete studies were included in the meta-analysis and used to construct 2 × 2 contingency tables. Improved diagnostic performance was observed when tissue (sensitivity 92.7% [95% confidence interval (CI) 82.0–98.0%]) and serum samples (sensitivity 91.3% [95% CI 86.0–95.0%]) were used, while the BruAb2_0168 locus was the gene of preference for optimal assay performance (sensitivity 92.3% [95% CI 87.0–96.0%] and specificity 99.3% [95% CI 98.0–100.0%]). Loop-mediated isothermal amplification (LAMP) had a higher diagnostic accuracy than polymerase chain reaction (PCR) and real-time quantitative PCR with sensitivity of 92.0% (95% CI 78.0–98.0%) and specificity of 100.0% (95% CI 97.0–100.0%).

Conclusion:

The findings of this study assign superior diagnostic performance in the detection of B. abortus to LAMP. However, due to limitations associated with decreased specificity and a limited number of published articles on LAMP, the alternative use of PCR-based assays including those reported in literature is recommended while the use of LAMP for the detection of bovine brucellosis gains traction and should be evaluated more comprehensively in future.

Molecular detection of Brucella abortus in wild and captive felids

Purpose

Brucellosis is a zoonotic disease of great public health importance. In wild animals, Brucella abortus is one of the most diagnosed species, mainly in enzootic environments where domestic animals share the same environment. B. abortus is common in environments shared by cattle, wild, and domestic animals. This study aimed to detect the presence of B. abortus DNA in free-ranging and captivity felids at Mato Grosso State, Brazil.

Method

Polymerase chain reaction, based on the genetic element IS711, was performed in blood samples collected from 23 free-ranging and captive felids. The species represented include Leopardus colocolo, Leopardus pardalis, Leopardus wiedii, Panthera onca, Puma concolor, and Puma yagouaroundi.

Results

DNA amplification of B. abortus was observed in only one captive P. concolor (4.34%).

Conclusion

The detection of this pathogen in captive animals using molecular tools demonstrates the importance of monitoring, as it raises concerns about the possibility of transmission between humans and wild and domestic animals, especially in regions of vast biodiversity, such as in the State of Mato Grosso, Brazil.

Brucella melitensis infection in dog: a critical issue in the control of brucellosis in ruminant farms

Canine brucellosis is a contagious disease associated with health implications for humans as well as for a wide range of wild and domesticated animals. In this study, 173 dog blood specimens were sampled from herding dogs in three different provinces including Tehran (n = 127), Qom (n = 40) and Alborz (n = 6) provinces. The presence of Brucella antibodies was determined using Rose Bengal plate test (RBPT), slow agglutination test (SAT) and 2-mercaptoethanol (2-ME), respectively. The seropositive samples were further screened using blood culture and PCR tests to identify and differentiate the implicated Brucella species. According to our results, 24.3% (42/173), 13.8% (24/173) and 6.3% (11/173) of blood samples were tested positive using RBPT, SAT and 2-ME, respectively. However, among 42 seropositive samples, only 38.1% (16/42) and 14.2% (6/42) were positive by PCR and culture, respectively. Brucella melitensis biovar 1 and biovar 2 was isolated from the bacterial cultures of 6 blood samples and confirmed by biotyping, AMOS PCR and Bruce-ladder PCR assays. These findings highlight the potential risk of Brucella transmission from dog to humans along with other livestock and reflect the critical role of infected dogs in the persistence of Brucella infections among ruminant farms. This study stresses the need for further epidemiological investigations on canine brucellosis among herding dogs and suggests the systematic screening of the disease among companion animals such as dogs in order to improve brucellosis surveillance and control programs.