Brucellosis Infection Research Articles

Detection of Brucellae in peripheral blood mononuclear cells for monitoring therapeutic efficacy of brucellosis infection

BackgroundBrucellosis is one of the most severe widespread zoonoses caused by the Gram-negative bacterium Brucella species. The diagnosis and clinical assessment of human brucellosis are very important for the management of patients, while there is a lack of effective methods to detect Brucellae. Classical culture of Brucella species is time consuming and often fails. A simple and sensitive assay is needed for diagnosis of Brucella infection and monitoring of treatment in man.MethodsBlood samples and peripheral blood mononuclear cells (PBMCs) were collected from 154 patients hospitalized for brucellosis. Brucella antibodies were detected by Rose Bengal Plate Test (RBPT), Standard Tube Agglutination Test (SAT) and enzyme-linked immunosorbent assay (ELISA). Intracellular Brucellae were detected by blood culture and immunofluorescence staining (IFS).ResultsAmong 154 brucellosis patients, 59.7% (92/154) were antibody reactive by RBPT, 81.8% (126/154) by SAT and 95.5% (147/154) by ELISA, respectively. Only 3.2% (5/154) of patient blood samples resulted in positive Brucella culture, while 68.8% (106/154) carried IFS detectable Brucella antigens in PBMCs. Gender (P = 0.01) but not age (P > 0.05) was a significant risk factor. The frequency of intracellular Brucella antigens was similar between patients receiving different treatment regimens (P > 0.05). However, a significant decrease of intracellular Brucellae was observed only in patients with acute brucellosis after the third course of treatment (P < 0.05), suggesting that current regimens to treat chronic brucellosis were not effective.ConclusionsIFS appears a sensitive assay for detection of Brucella antigens in PBMCs and could be used for diagnosis and therapeutic monitoring of brucellosis in clinical practice.

Epidemiology of human brucellosis and source of Brucella isolates in Hunan province

Objective: To analyze the epidemiological characteristics of human brucellosis and trace back source of infection of human brucellosis in Hunan province during 2010-2018, and provide evidence for the prevention and control of human brucellosis. Methods: The surveillance data of human brucellosis in Hunan during 2010-2018 were analyzed with software Excel 2016 and ArcGIS 10.5, the epidemic characteristics were described using cases number, constituent ratio and rate. The conventional biotype methods were used for the identification of Brucella species, UTS-PCR was applied to further confirm the results from conventional biotype detections, then six virulence genes of two clinical Brucella strains were detected by PCR assay. Cluster analysis of two Brucella strains were performed with Multiple locus variable-number tandem repeat analysis (MLVA) for the investigation of the infection source of human brucellosis. Results: From 2010 to 2018, a total of 728 human brucellosis cases were reported in Hunan with the annual incidence rate of 0.12/100 000. The incidence rate was 2.50/100 000 in Chenzhou and 1.90/100 000 in Yongzhou, higher than those in other areas. The number of counties reporting cases increased from 5 in 2010 to 69 in 2018. Most cases were reported in age group 45-54 years, accounting for 38.32% (279/728). The cases in farmers accounted for 59.07% (430/728) of the total. The male to female ratio of the cases was 2.75 ∶ 1. The reported case number was highest during May-July, accounting for 45.33% (330/728). The incidence was high in summer and autumn, and the peak was in May. The conventional identification showed that two strains were all Brucella melitensis biovar 1, consistent with UTS-PCR amplification results. Six virulence genes were found in two isolated strains, suggesting that the Brucella melitensis strains in this study had strong virulence. MLVA results confirmed that two strains detected in Hunan had complete identical MLVA-16 genotype with strains isolated from goat and camel in Inner Mongolia Autonomous Region, indicating that there was molecular epidemiology relationship between these strains and the source of infection were originated from Inner Mongolia. Conclusions: The epidemic of human brucellosis in Hunan is becoming serious, and disease has spread to general population and non-epidemic areas. Two Brucella melitensis strains detected in Hunan were originated from Inner Mongolia. The quarantine and inspection in animal transportation should be strengthened to prevent human outbreaks of brucellosis.

Serodiagnostic potential of Brucella outer membrane and periplasmic proteins

The aim of this study was to evaluate the serological diagnostic potential of the Brucella recombinant outer membrane (rOMP25, rOMP31) and periplasmic proteins (rBP26, rSOD) in a comparative way using an indirect enzyme-linked immunosorbent assay (i-ELISA). Rabbit and/or mouse antibodies to Brucella whole cell and/or soluble protein preparations recognized all recombinant proteins used, which confirms the expression of target antigens in E. coli in active form. The recombinant proteins showed different antigenicity to antibodies of cattle kept on a brucellosis-affected (endemic) farm and/or a new focus of infection. Thus, the presence of anti-Brucella antibodies was confirmed by i-ELISA/rSOD in 79% of cows from endemic conditions with positive results by conventional serological tests (RBPT and/or CFT). However, antibodies specific to this protein were detected in only 14% of seropositive animals kept in the hotbed of a new brucellosis infection. Moreover, rSOD-specific antibodies were not detected in the sera of vaccinated cattle from a brucellosis-free farm, whereas antibodies to other recombinant proteins were found in 2%-8% of animals. Using recombinant proteins in immunoassays significantly reduced the number of cows positive for brucellosis. Furthermore, there was not a single protein among the rOMPs that would show the total positive results of all proteins used. Thus, the development of reliable ELISA tests for the diagnosis of brucellosis requires further comprehensive study of the recombinant proteins in order to design a multiprotein antigen that consists of a combination of several proteins with diagnostic potential.

A multifaceted risk model of brucellosis at the human-animal interface in Egypt.

Brucellosis is a highly contagious zoonosis affecting humans and a wide range of domesticated and wild animal species. An important element for effective disease containment is to improve knowledge, attitudes and practices (KAP) of afflicted communities. This study aimed to assess the KAP related to brucellosis at the human-animal interface in an endemic area of Egypt and to identify the risk factors for human infection. A matched case-control study was conducted at the central fever hospitals located in six governorates in northern Egypt. Face-to-face interviews with cases and controls were conducted using a structured questionnaire. In total, 40.7% of the participants owned farm animals in their households. The overall mean practice score regarding animal husbandry, processing and consumption of milk and dairy products were significantly lower among cases compared with controls (-12.7±18.1 vs. 0.68±14.2, respectively; p<.001). Perceived barriers for notification of animal infection/abortion were predominate among cases and positively correlated with participants' education. The predictors of having brucellosis infection were consumption of unpasteurized milk or raw dairy products and practicing animal husbandry. Applying protective measures against infection significantly reduced its risk. A model predicting risk factors for brucellosis among those who own animal showed that frequent abortions per animal increased the chance for brucellosis infection among human cases by 50-fold (95% CI: 8.8-276.9), whereas the use of protective measures in animal care reduced the odds (OR=0.11 [95% CI: 0.03-0.45]). In conclusion, consumption of unprocessed dairy products was equally important as contact with infected/aborted animals as major risk factors for Brucella spp. infection among humans in Egypt. There is poor knowledge, negative attitudes and risky behaviours among villagers which can perpetuate the risk of brucellosis transmission at the human-animal interface. This supports the need for integrating health education into the national brucellosis control programme.

Differentiation of Brucella species by repetitive element palindromic PCR

Brucellosis is one of the most prevalent zoonotic diseases among animals and humans. It is a well known fact that the differentiation and rapid typing of Brucella spp. is crucial for the early detection of infection, prevention of infection progress, and/or introducing treatment solutions. Analyzing the sequences could be an effective method in achieving these purposes. The aim of this study was to analyze palindromic sequences for Brucella spp., differentiation using the rep-PCR method. The authors collected 80 animal samples, which were suspected to brucellosis infection. After the cultivation of Brucella, identification was performed through standard biochemical, microbiological, and IS711 PCR assays. By designing the specific primers for polymorphism sequence, the rep-PCR was performed. The resultant pattern was compared with the obtained patterns of the standard Brucella melitensis and Brucella abortus samples, which showed dissimilar patterns. For this reason, the PCR products were sequenced, and consequently two new patterns were introduced. This rapid and repeatability assay has the ability to potentially differentiate the B. abortus and B. melitensis species, which could be useful in early diagnosis and treatment of patients with brucellosis.

Seroprevalence of Brucellosis Infection in Sheep and Goats of Raichur District in Karnataka

Seroprevalence of Brucellosis Infection in Sheep and Goats of Raichur District in Karnataka

Application of dynamic contrast enhanced MRI in the diagnosis of brucellar spondylitis

ObjectiveTo explore the value of Dynamic Contrast Enhanced(DCE) MRI in the clinical diagnosis, especially in the early stage of brucellar spondylitis. MethodsFifty six patients and ten healthy volunteers were included in this study. All the patients with brucellosis infections, ranged in age between thirty-five and sixty-two years old. This sample included thirty-two patients with brucellar spondylitis and twenty-four patients with strong back pain, however, the routine MRI showed no obvious abnormalities. The participants were scanned with routine MRI and DCE-MRI. The values of Ktrans,Kep,Ve, and Vp between the vertebral lesions of the patients suspected of brucellar spondylitis with no obvious abnormalities and the normal bodies in healthy volunteers were measured and compared. Under the Receiver Operating Characteristic(ROC) curve analysis, the sensitivity and specificity of the above four parameters were calculated. ResultsQuantitative parameters in this study have normal distribution and expressed as the mean (±standard deviation). The Ktrans, Kep, Ve and Vp values of the vertebral bodies in the pathological group were:(0.856 ± 0.539)ml/min, (1.482 ± 0.711)ml/min, (0.542 ± 0.267), and (0.034 ± 0.017), respectively. The normal vertebral bodies were (0.315 ± 0.298)ml/min, (0.713 ± 0.548)ml/min, (0.358 ± 0.259), and (0.056 ± 0.031), respectively. The differences between the two groups were statistically significant (P < 0.05). The values of Ktrans, Kep, Ve and Vp in the early lesion group were (0.666 ± 0.411) ml/min, (1.225 ± 0.824) ml/min, (0.429 ± 0.287) and (0.033 ± 0.025), respectively. Compared with the normal group, the values of Ktrans, Kep and Vp had significant difference (P < 0.5), and the values of Ve had no significant difference (P > 0.05); compared with the lesion group, the differences of Ktrans, Kep, Ve and Vp had no statistical significance (P > 0.05). The areas of Ktrans, Kep under the ROC curve were the largest. ConclusionThe DCE-MRI quantitative analysis plays an important role in the early diagnosis of brucellar spondylitis. This technique should be further studied and widely applied.

Biosurveillance study of Schmallenberg disease in Azerbaijan in 2012-2017

ObjectiveSchmallenberg virus (SBV) is an orthobunyavirus that primarily infects domestic and wild ruminants and causes symptoms such as transient fever, diarrhea, reduced milk production, congenital malformations and abortion. The first virus was identified in 2011 at the onset of a major outbreak in Europe (Germany, Hungary, and France).IntroductionIn 2012 - 2017 in Azerbaijan there was an unexpected increase of abortions in cattle and sheep that was unrelated to brucellosis or chlamydia infection. The first confirmed case of Schmallenberg disease was received from Beylagan district of Azerbaijan in October 2012. The import of cattle from Europe to Azerbaijan has commenced in 2012. Therefore, the surveillance study was launched to determine spread of infection among cattle and sheep and to monitor the situation in the country.MethodsState Veterinary Control Service notified 42 Regional Veterinary Offices of Azerbaijan to commence the monitoring of Schmallenberg disease. Blood samples were collected from sheep, and cattle and biopsies of heads or necks from aborted fetuses were sampled too.. The collected samples were tested in the Republican Veterinary Laboratory. ELISA was used to investigate the presence of specific antibodies against Schmallenberg virus in the blood samples using IDEXX Schmallenberg Ab Test Kit. The commercially available real-time PCR kits (VetMAX™ Schmallenberg Virus Kit) were applied to test the biopsy samples. Both tests were recommended by the World Organization for Animal Health.ResultsTotal, 40,257 blood samples were collected from suspicious cattle and sheep. 671 biopsies samples were taken from fetuses. 4,281 cattle and 999 sheep with antibodies against SBVwere detected. The PCR results showed that the 77 biopsies samples were positive for SBV. The highest numbers of seropositive animals were found in Ganja, Aghdash, Barda, and Baku.ConclusionsThis biosurveillance study determined SBV in the samples of cattle and sheep in Azerbaijan, therefore, it is important to carry out annual seromonitoring and start the vaccination program. It is essential to check the passport of imported cattle, which has the disease history and seroprevalence of SBV.ReferencesLaloy, E., Breard, E., Sailleau, C., Viarouge, C., Desprat, A., Zientara, S., Klein, F., Hars, J., Rossi, S., 2014. Schmallenberg virus infection among red deer, France, 2010-2012. Emerg. Infect. Dis. 20, 131–134. https://doi.org/10.3201/eid2001.130411Larska, M., Krzysiak, M.K., Kesik-Maliszewska, J., Rola, J., 2014. Cross-sectional study of Schmallenberg virus seroprevalence in wild ruminants in Poland at the end of the vector season of 2013. BMC Vet. Res. 10, 967. https://doi.org/10.1186/s12917-014-0307-3

Sero-prevalence of brucellosis among slaughterhouse workers in Bahr el Ghazal region, South Sudan

BackgroundBrucellosis is an infectious zoonotic disease and is common especially among pastoral communities in most low and middle-income countries. The aim of this study was to determine sero-prevalence, and risk factors of Brucella infection among Slaughterhouse workers, in Bahr el Ghazal region, South Sudan.MethodsA cross sectional study was conducted among Slaughterhouse workers in Bahr el Ghazal region, South Sudan from December 2015 to May 2016. A pre-tested questionnaire was used in data collection. Each randomly selected participant was interviewed and a venous blood sample collected. The blood samples were screened for Brucellosis infection using Rose Bengal Plate Test (RBPT) and confirmed using Competitive Enzyme link Immuno Sorbet Assay (c-ELISA). Data was analyzed using Stata version 13 at 95% level of confidence.ResultsA total of 234 Slaughterhouse workers were screen for Brucella infection. Overall, a third, 32.1% (75/234) of the participants were sero-positive for brucellosis. The prevalence of brucellosis was higher, 17.1% (40/234) in Wau state compared to other states. There was high prevalence among males, 28.6% (67/234) compared to females 3.4% (8/234). The mean age of study participants was 34.4 ± 9.6 years. A high proportion, 12.8% (30/234) of participants with confirmed brucellosis infection were 31–40 years of age. Brucellosis prevalence was high among butchers, 14.5% (34/234), and meat handlers, 9.0% (21/234).ConclusionsBrucellosis is common among animal slaughterhouse workers in Bahr el Ghazal region, South Sudan. There is need for public awareness campaigns and educational programs to help sensitize communities on Brucella infection.

FEATURES OF SEASONAL MANIFESTATION OF BRUCELLOSIS INFECTION AMONG THE POPULATION OF THE REPUBLIC OF TAJIKISTAN

The aim of this work was to study modern manifestations of seasonal brucellosis among the population of the Republic of Tajikistan. The materials and methods: of the study were the official statistics, as well as the results of previously performed studies on the risk assessment of the incidence in population. A retrospective epidemiological analysis of annual incidence rate for the period from 1997 to 2016 was conducted, depending on the most significant social and environmental risk factors. Results. The article shows the impact on the annual incidence rate of socio-economic transformations, including the privatization of collective livestock farms, accompanied by the massive movement of farm animals to private ownership, the loss of practice in animal breeding, and changes in environmental and climatic conditions. Against the background of the intensification of sheep breeding, there is a tendency in seasonality smoothing and shifting the maximum levels of population incidence of brucellosis to the spring season. Conclusion. The modern features of seasonal manifestation of brucellosis infection in the Republic of Tajikistan make it necessary to apply a differentiated approach to planning and conducting preventive measures in various areas of the country.

A high-throughput screening for inhibitors of riboflavin synthase identifies novel antimicrobial compounds to treat brucellosis.

Brucella spp. are pathogenic intracellular Gram-negative bacteria adapted to life within cells of several mammals, including humans. These bacteria are the causative agent of brucellosis, one of the zoonotic infections with the highest incidence in the world and for which a human vaccine is still unavailable. Current therapeutic treatments against brucellosis are based on the combination of two or more antibiotics for prolonged periods, which may lead to antibiotic resistance in the population. Riboflavin (vitamin B2) is biosynthesized by microorganisms and plants but mammals, including humans, must obtain it from dietary sources. Owing to the absence of the riboflavin biosynthetic enzymes in animals, this pathway is nowadays regarded as a rich resource of targets for the development of new antimicrobial agents. In this work, we describe a high-throughput screening approach to identify inhibitors of the enzymatic activity of riboflavin synthase, the last enzyme in this pathway. We also provide evidence for their subsequent validation as potential drug candidates in an invitro brucellosis infection model. From an initial set of 44000 highly diverse low molecular weight compounds with drug-like properties, we were able to identify ten molecules with 50% inhibitory concentrations in the low micromolar range. Further Brucella culture and intramacrophagic replication experiments showed that the most effective bactericidal compounds share a 2-Phenylamidazo[2,1-b][1,3]benzothiazole chemical scaffold. Altogether, these findings set up the basis for the subsequent lead optimization process and represent a promising advancement in the pursuit of novel and effective antimicrobial compounds against brucellosis.

Field Epidemiological Study of the Risk Factors of Brucellosis Insidence in the Jalal-Abad Region of Kyrgyz Republic

Objective of this study was to determine the risk factors of brucellosis morbidity in the Jalal-Abad Region of Kyrgyzstan. Materials and methods. A case-control study was conducted in the process of field epidemiological survey of risk factors of brucellosis incidence that lasted for 6 month in the year 2018 in the Jalal-Abad Region. The study involved 180 respondents (90 cases and 90 controls). Cases of brucellosis were identified on the basis of epidemiological, clinical and laboratory criteria. Respondents were interviewed using the developed questionnaire to obtain information on the risk factors. To determine the exposure/ disease ratio, the odds ratio (OR) was calculated for each factor. Results and discussion. It was revealed that the intake of unpasteurized homemade cream (OR = 2.8; CI = 1.5–5.2; p = 0.0001), grilled meat (shish-kebabs) (OR = 5.1; CI = 2.5–10.4; p = 0.0001); cases of abortion or stillbirth among animals in households (OR = 11.3; CI = 4.2–30.6; p = 0.0001), stall cleaning (OR = 2.5; CI = 1.3–4.626; p = 0.0001), shearing of sheep (OR = 2.6; CI = 1.2–5.6; p = 0.01) and animal slaughter (OR = 2.9; CI = 1.2–6.5; p = 0.01) are statistically significant in relation to the risk of infection with brucellosis. To that end, the listed factors are the key risk factors for brucellosis infection. The livestock keeping in private households (OR = 7.1; CI = 3.0–16.5; p = 0.0001) is also of great importance as a risk factor. For implementation of any preventive measures against brucellosis the value of the OR indicator (OR = 0.8, CI = 0.04–0.18; p = 0.0001) proves their reasonability.

Risk factors for new bovine brucellosis infections in Colombian herds

BackgroundBovine brucellosis is a zoonotic disease that causes substantial economic losses and has a strong impact on public health. The main objective of this paper is to determine the risk factors for new infections of Brucella abortus on Colombian cattle farms previously certified as being free of brucellosis. A case-control study was conducted by comparing 98 cases (farms certified as brucellosis-free for three or more years but became infected) with 93 controls (farms that remained brucellosis-free during at least the previous three years). The farms were matched by herd size and geographical location (municipality). Information was obtained via a questionnaire completed by veterinary officers through a personal interview with the herd owners.ResultsTwo-thirds of the herds (67%) were dairy herds, 16% were beef herds, and 17% were dual-purpose (beef and milk) herds. After exploratory univariate analysis, all explanatory variables with a p-value of ≤0.20 were included in a logistic regression model using the forward stepwise method to select the model with the best goodness of fit. The significant risk factors were the replacement of animals from farms not certified as brucellosis-free compared to replacement from certified brucellosis-free farms (OR = 4.84, p-value < 0.001) and beef cattle farms compared to dairy cattle farms (OR = 3.61, p-value = 0.017). When herds with and without artificial insemination were compared, it was observed that farms that used natural breeding with bulls from non-certified herds had a higher risk than farms using artificial insemination (OR = 2.45, p-value = 0.037), but when the bulls came from brucellosis-free farms, farms with natural breeding were less affected (OR = 0.30, p-value = 0.004) than farms using artificial insemination, whether with frozen semen from certified brucellosis-free herds or fresh semen from uncontrolled herds. The latter is commonly sold to neighbouring farms.ConclusionsThe government should make efforts to inform farmers about the risks involved in the introduction of semen and replacement heifers from farms that are not certified as brucellosis-free and to establish measures to control these practices.

Occurrence of brucellosis in cattle and goats in Malaysia: a review

The occurrence of brucellosis in Malaysian livestock population even though reported for many decades is low when compared to other countries in Asia. The presence of brucellosis in Malaysia was first confirmed in 1950 when B. abortus was first isolated from large ruminants. However, it was observed that there was a shift in the status of bovine brucellosis and unsubstantiated evidence suggests an increase of brucellosis infection among cattle. The most reliable and unambiguous method of diagnosing Brucella specie in animals is by isolation. Microscopic examination of smears made from vaginal, placenta or aborted foetus swabs have proven to be promising in the bacteriological examination of B. melitensis. Since the original recognition of the causative agent of brucellosis, large numbers of serological tests and various modifications to enhance accuracy have been developed for diagnosis of brucellosis. Serological testing for brucellosis among livestock is usually conducted as a component of the disease eradication and surveillance program. Rose Bengal plate test is the most widely used screening test for brucellosis. The test is internationally acknowledged as the choice for the screening of brucellosis in small ruminants and the OIE considers this test “prescribed tests for trade”. Many countries are undergoing a re-emergence of the disease especially in sheep and goats. In many countries, vaccination of animals has been found as the most successful method for prevention and control of brucellosis. Crucial factors for the successful eradication programme are the implementation of an effective surveillance system with adequate laboratory support.

Lipopolysaccharide-binding protein, neopterin and interferon-gamma as indices of inflammation activity in patients with acute brucellosis

Brucellosis is characterized by nonspecific clinical manifestations, the possibility of subclinical flow, the development of relapses and chronic course. Currently, there are nolaboratory criteria to assess the activity of inflammation in brucellosis, the effectiveness of the therapy, predict the outcome of the disease and the risks of recurrence. Available in clinical practice, laboratory tests to assess inflammation, in particular, erythrocyte sedimentation rate, C-reactive protein, leukocyte level, with brucellosis infection are almost not informative. An important role in the development of the cellular immune response against brucella is played by interferon-γ, lipopolysaccharide-binding protein and neopterin. The aim of the study was to determine the level of lipopolysaccharide-binding protein, neopterin and interferon-γ,in the serum of patients with acute form of brucellosis beforeand after antibacterial treatment. When studying the blood of patients with acute brucellosis before and after therapy, the indices of neopterin, lipopolysaccharide-binding protein and interferon-γ were significantly higher than normalvalues. The obtained results testify to the persisting active inflammation and the formation of a chronic brucellosis. Determination of the level of lipopolysaccharide-binding protein, neopterin and interferon-γ in the blood of patients withbrucellosis can be used as markers of inflammation and in monitoring the effectiveness of antibacterial therapy.

Seroreactivity and Risk Factors Associated with Human Brucellosis among Cattle Slaughterhouse Workers in South Korea

The prevalence rate of human brucellosis in high-risk populations, as well as their risk factors, have not been well understood in South Korea. In this cross-sectional study, we investigated the seroreactivity and risk factors associated with human brucellosis among South Korean cattle slaughterhouse workers. We enrolled 922 subjects working in 71 slaughterhouses across the country in 2012. A structured questionnaire was used to obtain data from the subjects, following which blood samples were collected and tested using the microagglutination test; serum titers ≥ 1:20 were considered reactive. Independent risk factors were identified using multivariate logistic regression analysis with backward elimination. Overall, 62 of 922 participants (6.7%) exhibited seroreactivity for brucellosis, and 0.4% had a seroprevalence at a dilution of 1:160. Multivariate analysis revealed that the risk factors for human brucellosis seroreactivity included large-scale slaughtering (≥100 cattle per day; odds ratio (OR), 5.41; 95% confidence interval (CI), 2.95–9.91) and medium-scale slaughtering (50–99 cattle per day; OR, 2.53; 95% CI, 1.16–5.51). Moreover, the risk of brucellosis infection was significantly lower among slaughterhouse workers who always wear protective glasses (OR, 0.27; 95% CI, 0.11–0.69) than in those who sometimes or rarely wore such glasses. Regular and consistent use of personal protective equipment, especially protective glasses, should be encouraged among cattle slaughterhouse workers to reduce brucellosis infection.

Molecular Investigation of the Transmission Pattern of Brucella suis 3 From Inner Mongolia, China.

Brucellosis is an endemic disease in China affecting both humans and livestock. The aim of the present study was to analyze two Brucella strains isolated from sheep spleens from Ulanqab in Inner Mongolia, China using classical and molecular typing techniques. The two strains were identified as Brucella suis biovar 3 and were closely related to isolates previously obtained from two different hosts (human and swine) in Guangxi Province. Our results suggest that B. suis can be directly or indirectly transferred from swine to sheep, which act as reservoirs for B. suis infection and later transmitted to humans. Multiple locus variable-number tandem repeat analysis (MLVA) is a useful tool for tracing the geographical origin of brucellosis infections and elucidating its transmission patterns.

Analysis of domestic animal movements in Colombia (2006-2014) and their possible influence on the bovine brucellosis spread.

Bovine brucellosis is a zoonotic disease that causes great economic losses. The disease is endemic in Colombia and animal movements from infected herds carry a risk of introduction to other herds. With the objective of analyzing the animal movements and determining their relationship with bovine brucellosis, we performed a descriptive analysis of the space-time movement of livestock in Colombia between 2006 and 2014. Multiple linear regression models (MLR) were employed to determine the relationship between brucellosis status and animal movements at the province level. The prevalence of bovine brucellosis in cattle was the dependent variable, and a total of 14 independent variables related to location, year, census, and animal movements were included. The prevalence of bovine brucellosis was significantly affected by the province (F = 3.42; P < 0.001), the year (F = 9.03; P < 0.001), and bovine (F = 5.45; P = 0.02) and equine movements (F = 3.8; P = 0.053). Fewer cattle and more horses entered provinces with high prevalence than those with low prevalence, indicating the possible relationship between the animal movements and the brucellosis infection in the country.

On the dynamics of brucellosis infection in bison population with vertical transmission and culling

We introduce a new mathematical modeling framework that seek to improve our quantitative understanding of the influence of chronic brucellosis and culling control on brucellosis dynamics in periodic and non-periodic environments. We conduct both epidemic and endemic analysis, with a focus on the threshold dynamics characterized by the basic reproduction numbers. In addition, we also perform an optimal control study to explore optimal culling strategy in periodic and non-periodic environment.

Dynamics and Stability Analysis of a Brucellosis Model with Two Discrete Delays

We present a mathematical model for brucellosis transmission that incorporates two discrete delays and culling of infected animals displaying signs of brucellosis infection. The first delay represents the incubation period while the second account for the time needed to detect and cull infectious animals. Feasibility and stability of the model steady states have been determined analytically and numerically. Further, the occurrence of Hopf bifurcation has been established. Overall the findings from the study, both analytical and numerical, suggest that the two delays can destabilize the system and periodic solutions can arise through Hopf bifurcation.