Detection of Brucella antibodies in domestic animals of southern Cameroon: Implications for the control of brucellosis

Seroprevalence study of brucellosis in wild boar hunted for private consumption in northeast Portugal

Brucellosis is an important infectious disease caused by bacteria of the genus Brucella. In the northeast region of Portugal, infection with Brucella melitensis is endemic in small ruminants, and there are also humans' cases. However, the epidemiological role of the wild boar in the dynamics of this disease in this region is unknown. In this study, a total of 332 blood samples were collected from wild boar hunted in thirty-six hunting areas during the 2022/2023 hunting season. All were taken by the hunters for private consumption, with no evisceration or examination in the field. Serum samples were tested by indirect ELISA (i-ELISA). It was observed that 88 wild boars were exposed to Brucella spp., pointing to a seroprevalence of 26.5% (95% CI: 21.8 - 31.3%). This high prevalence underlines the importance that wild boar may have in the dynamics of this disease in the region and its potential transmission to other animals, and to humans (for example, during the handling of carcasses). Increased awareness and knowledge of brucellosis in wild boar is essential for the implementation of effective practices and habits and, consequently, for the control and prevention of this important zoonosis.

A study on the epidemiology of brucellosis in bovine population of peri-urban and rural areas of district Multan, southern Punjab, Pakistan

BACKGROUND

Brucellosis is a zoonotic disease caused by a bacterial pathogen belonging to the genus Brucella. It is one of the most frequent bacterial zoonoses globally but unfortunately, it is still considered as a neglected disease in the developing world. Keeping in view, this study was conducted to determine the prevalence and risk determinants of brucellosis in large ruminants of peri-urban and rural areas of district Multan-Pakistan. For this purpose, blood samples (n = 490) were collected from the cattle (n = 245) and buffalo (n = 245) population of the study area and subjected to preliminary screening of brucellosis using local and imported RBPT reagents. All the samples were further analyzed using commercially available multi-specie indirect ELISA kit followed by their confirmation by PCR using genus and species-specific primers. Data obtained from lab analysis and questionnaires were subjected to statistical analysis for Pearson Chi-square, Odds Ratio and Confidence intervals (95%).

RESULTS

The results showed that the maximum seropositivity was recorded with local RBPT reagent (VRI, Pakistan; 12.45%; 95%CI = 9.72-15.65%) followed by RBPT-IDEXX (12.24%; 95%CI = 9.52-15.45%) and RBPT-ID.vet (11.84%; 95%CI = 9.18-14.95%) however statistical difference was non-significant (P = 0.956). The ELISA results showed an overall seroprevalence rate of 11.22% (95%CI = 8.59-14.33%) with comparatively higher rate in cattle (12.65%; 95%CI = 8.82-17.44%) as compared to buffaloes (9.80%; 95%CI = 6.49-14.15%). The PCR analysis confirmed the presence of genus Brucella in all seropositive samples whereas frequency of B. abortus and B. melitensis in seropositive samples was 80% and 20%, respectively. The co-existence of both species was also observed in 5.45% samples. The statistical analysis showed a significant association of bovine brucellosis with herd size, breed, reproductive disorders, mode of insemination, educational status and farmers' awareness about brucellosis (P < 0.05). Conversely, locality, age, weight, gender, pregnancy status, parity and puberty status had no associations with brucellosis (P > 0.05).

CONCLUSION

In conclusion, brucellosis is prevalent in large ruminants of district Multan, Pakistan. It is suggested to devise and implement stringent policies for the effective control and prevention of brucellosis in the region. Further, the current situation also warrants the need to strengthen interdisciplinary coordination among veterinarians and physicians in one health perspective to ensure and strengthen the human and animal health care systems in the region.

Use of the quantum dot-labeled solid lipid nanoparticles for delivery of streptomycin and hydroxychloroquine: A new therapeutic approach for treatment of intracellular Brucella abortus infection

Brucellosis is considered one of the most important infectious diseases affecting any tissue and organ in the human body. Due to the intracellular pathogenesis of Brucella species, the use of conventional antibiotics for managing chronic brucellosis has several limitations. Therefore, the study focused on the use of solid lipid nanoparticles (SLN) to deliver streptomycin (STR) for intracellular infection, with or without the combination of hydroxychloroquine (HCQ) to evaluate if there might be a boost in the antibiotic effect when using the STR or STR-NPs alone. We used the double emulsion technique to synthesize Nano drug carriers; afterward, the physicochemical characteristics of synthesized Nano drug carriers were determined. The in vitro antibacterial activity of free drugs and Nano drug carriers were evaluated using well diffusion, broth microdilution assays (BMD), and murine macrophage-like cells cell line J774A.1. Additionally, acute and chronic phases of brucellosis were inducted into Wistar rats, and healing capacity of Nano drug carriers on liver and spleen tissues was compared with free drugs. The zeta potential of nanoparticles, means of size, Polydispersity Index (PDI), drugs loading, and encapsulation efficiency were 15.2 mV, 312.5 ± 26 nm, 0.433 ± 0.09, 16.6% and 89.5%, respectively. Well diffusion and BMD methods did not show a significantly differ between free drugs and nano drug carriers. However, the Nano drug carriers remarkably decreased the number of bacteria in the cell line compared to the free drugs. STR/HCQ-SLN enhanced the healing processes of the liver and spleen after brucellosis induction. STR/HCQ-SLN showed better inhibitory effects against the chronic phase of B. abortus infection in comparison to the STR-SLN, but this difference was not statistically significant. Using nanoplatforms to enhance conventional anti-brucellosis agents is promising, green and safe. Due to the continuous release of drugs, drugs increase their accumulation at the site of infection, causing a more significant effect on the chronic and acute phases of brucellosis.

Detection of Brucella S2 vaccine strain by a loop-mediated isothermal amplification (LAMP) method

Introduction

Brucellosis is a highly prevalent zoonotic disease caused by Brucella spp. Brucella suis S2 vaccination is an effective strategy to prevent animal brucellosis. However, S2 induces antibodies against the smooth lipopolysaccharide,making it challenging to distinguish field infected from vaccinated livestock. Early and accurate diagnosis is essential for infection control and prevention. In this study, we aimed to develop a quick and accurate assay to distinguish the BrucellaS2 vaccine strain from closely related B. abortus and B. melitensis.

Methods

Whole-genome sequencing of B. suis S2 was performed, and the sequence was compared with that of the genomes of B. abortus and B. melitensis. One specific gene, GL_0002189, was selected as a marker to differentiate the BrucellaS2vaccine strain from B. abortus and B. melitensis. A loop-mediated isothermal amplification (LAMP) assay was developed, based on the GL_0002189 gene, and then assessed for target specificity, lower limit of detection, and repeatability.

Results

Our results revealed that there was no cross-reaction with other strains, and the LAMP assay displayed high sensitivity for detecting S2 with a minimum detection limit of 18.9×103 copies/µL DNA input, it is nearly 100 times higher than conventional PCR technology. Concordance between the LAMP assay and a conventional polymerase chain reaction method was assessed using 54 blood samples collected from sheep with suspected brucellosis. Total concordance between the two assays was 92.6%, without a significant difference (p > 0.05) in the test results.

Conclusion

This is the first report of a LAMP assay for the detection of the B. suis S2vaccine strain. Our approach can be helpful for the control and eradication of brucellosis, and its simplicity in requiring no specialized equipment or personnel makes it useful for implementation in resource-limited settings as well as for field use.

Co-Delivery of Doxycycline and Hydroxychloroquine Using CdTe-Labeled Solid Lipid Nanoparticles for Treatment of Acute and Chronic Brucellosis

Brucellosis is a systemic disease in both acute and chronic forms which can affect any organ or tissue in the body. One of the biggest issues in treating this disease is its relapse. In this study, a complete treatment of brucellosis was evaluated using enhanced performance of doxycycline and hydroxychloroquine drugs by using solid lipid nanoparticles (SLN) conjugated cadmium-telluride quantum dots. The double emulsion method was used to prepare SLN and cadmium-telluride quantum dots. The physicochemical properties of NPs were determined. The effect of nanoparticle-loaded antibiotics against Brucella melitensis was determined by well diffusion, minimum inhibitory concentration (MIC), cell culture, and animal studies. The means of particle size, PDI, zeta potential, drugs loading, and encapsulation efficiency were 214 ± 25 nm, 0.385 ± 0.022, −18.7 ± 2.3 mV, 17.7 ± 1.5%, and 94.15 ± 2.6%, respectively. The results of FTIR and DSC showed that no chemical reaction occurred between the components of the NPs. The effect of free drug and NPs on bacteria was the same by well diffusion and MIC method. Drug-loaded NPs significantly reduced the number of CFUs in the cell line and acute and chronic brucellosis compared to the free drug. In conclusion, the synthesized nanoparticles were safe and green. With the slow release of the drug (100 h), the accumulation of the drug at the bacterial site increases and causes a greater effect on the B. melitensis and improves the disease of brucellosis. The use of synthesized nanodrugs in this study had promising therapeutic results.

Scoping review of brucellosis in Cameroon: Where do we stand, and where are we going?

Brucellosis is a zoonotic disease known to be endemic to parts of western and sub-Saharan Africa. However, the epidemiology for humans and animals remains largely unknown in many of these countries with Cameroon being a typical example. Despite common knowledge that brucellosis affects livestock, the actual number of infected animals remains unknown. Through a scoping review, the current known status of the disease is described. The aim is to ascertain relevant and publicly accessible research and knowledge of human and animal brucellosis in the country, and to provide an overview of the factors associated with its known persistence. Seroprevalence has been estimated and published in 12 separate instances (1 human; 9 cattle; 1 human and cattle; and 1 that includes cattle, pigs, and small ruminants), between 1982 and 2020, in 9 of the country's 10 geopolitical regions. In 1983, Brucella abortus and B. melitensis were isolated in cattle, but no further bacterial isolation has been published since. The seroprevalence from 196 total humans has ranged between 5.6% and 28.1%, and between 3.0% and 30.8% for 14,044 total cattle. As there is no ongoing surveillance program, it is not currently possible to identify the specific Brucella spp. that are endemic to the country and its regions. There are sufficient agricultural systems of cattle, pigs, goats, and sheep to sustain the presence of multiple Brucella spp. Surveillance information is the cornerstone of epidemiologic decision making, and is needed to direct policy makers, public health authorities, and veterinary services to appropriate actions. A combination of serological and molecular based diagnostics for surveillance is necessary to identify, quantify, and direct the appropriate public health interventions. Cameroon has an opportunity to build public and animal health infrastructure, leading the way for central Africa in the management and future eradication of brucellosis.

Detection of Brucella antibodies in domestic animals of southern Cameroon: Implications for the control of brucellosis

Brucellosis is one of the world's most widespread bacterial zoonoses caused by Brucella. It leads to considerable economic losses as a result of low productivity of infected animals and the long debilitating illness in humans. Despite its impact on human and animal health, little attention has been paid on Brucella infections in domestic animals. It is in this light that the prevalence of Brucella antibodies was determined in domestic animals with the overarching goal of improving our knowledge on brucellosis in southern Cameroon. During cross-sectional studies conducted from December 2016 to August 2018 in five sites of southern Cameroon, blood samples were collected in cattle, sheep, goat, pig and dog. Plasma was obtained from each blood sample and Brucella antibodies were detected using the Rose Bengal test and the enzyme-linked immunosorbent assay (ELISA). From 1873 animals that were sampled, the overall prevalence of Brucella antibodies using Indirect enzyme-linked immunosorbent assay (i-ELISA) was 6.35% (118/1873): 9.12% (78/855) in cattle; 8.04% (30/373) in sheep; 6.06% (2/33) in dog, 1.87% (3/160) in pig and 1.1% (5/452) in goat. Between animal species (p-value < .0001, x2  = 33.63) as well as sampling sites (p-value = .0001, x2  = 18.97), significant differences were observed in the prevalence of Brucella antibodies. Yoko and Noun localities have shown the highest prevalence of 8.6% (30/348) and 7.2% (78/1070), respectively. This prevalence was significantly higher (p = .03, x2  = 1.25) in female than male cattle. Between adult (16.923%) and young cattle (7.8%), significant difference (p = .04, x2  = 6.42) was observed in the prevalence of Brucella antibodies. This study shows that the prevalence of Brucella antibodies varies between animal species and localities. It also shows several domestic animals of southern Cameroon that have been in contact with Brucella. It enabled to identify villages where investigations on the transmission dynamic must be focused for the final goal of developing control measures for this neglected zoonotic disease.