Epidemiology of brucellosis among cattle in Korea from 2001 to 2011

Trends in Nationally Notifiable Infectious Diseases in Humans and Animals during COVID-19 Pandemic, South Korea

We investigated trends in notifiable infectious diseases in both humans and animals during the COVID-19 pandemic in South Korea and compared those data against expected trends had nonpharmaceutical interventions (NPIs) not been implemented. We found that human respiratory infectious diseases other than COVID-19 decreased by an average of 54.7% after NPIs were introduced. On the basis of that trend, we estimated that annual medical expenses associated with respiratory infections other than COVID-19 also decreased by 3.8% in 2020 and 18.9% in 2021. However, human gastrointestinal infectious diseases and livestock diseases exhibited similar or even higher incidence rates after NPIs were instituted. Our investigation revealed that the preventive effect of NPIs varied among diseases and that NPIs might have had limited effectiveness in reducing the spread of certain types of infectious diseases. These findings suggest the need for future, novel public health interventions to compensate for such limitations.

A review of three decades of use of the cattle brucellosis rough vaccine Brucella abortus RB51: myths and facts

Cattle brucellosis is a severe zoonosis of worldwide distribution caused by Brucella abortus and B. melitensis. In some countries with appropriate infrastructure, animal tagging and movement control, eradication was possible through efficient diagnosis and vaccination with B. abortus S19, usually combined with test-and-slaughter (T/S). Although S19 elicits anti-smooth lipopolysaccharide antibodies that may interfere in the differentiation of infected and vaccinated animals (DIVA), this issue is minimized using appropriate S19 vaccination protocols and irrelevant when high-prevalence makes mass vaccination necessary or when eradication requisites are not met. However, S19 has been broadly replaced by vaccine RB51 (a rifampin-resistant rough mutant) as it is widely accepted that is DIVA, safe and as protective as S19. These RB51 properties are critically reviewed here using the evidence accumulated in the last 35 years. Controlled experiments and field evidence shows that RB51 interferes in immunosorbent assays (iELISA, cELISA and others) and in complement fixation, issues accentuated by revaccinating animals previously immunized with RB51 or S19. Moreover, contacts with virulent brucellae elicit anti-smooth lipopolysaccharide antibodies in RB51 vaccinated animals. Thus, accepting that RB51 is truly DIVA results in extended diagnostic confusions and, when combined with T/S, unnecessary over-culling. Studies supporting the safety of RB51 are flawed and, on the contrary, there is solid evidence that RB51 is excreted in milk and abortifacient in pregnant animals, thus being released in abortions and vaginal fluids. These problems are accentuated by the RB51 virulence in humans, lack diagnostic serological tests detecting these infections and RB51 rifampicin resistance. In controlled experiments, protection by RB51 compares unfavorably with S19 and lasts less than four years with no evidence that RB51-revaccination bolsters immunity, and field studies reporting its usefulness are flawed. There is no evidence that RB51 protects cattle against B. melitensis, infection common when raised together with small ruminants. Finally, data acumulated during cattle brucellosis eradication in Spain shows that S19-T/S is far more efficacious than RB51-T/S, which does not differ from T/S alone. We conclude that the assumption that RB51 is DIVA, safe, and efficaceous results from the uncritical repetition of imperfectly examined evidence, and advise against its use.

Bifurcation analysis of a sheep brucellosis model with testing and saturated culling rate

Testing-culling is a very effective measure for the prevention and control of animal diseases. In this paper, based on sheep brucellosis control policies and animal testing characteristics and considering the limitation of culling resources, a dynamic model is established to study the impact of testing-culling measure. Theoretical analysis reveals that the model may have one or three positive equilibria. The equilibrium in the middle is always unstable, and the model shows saddle-node bifurcation, generalized Hopf bifurcation and Bogdanov-Takens bifurcation. Moreover, the theoretical results are verified via numerical analysis. These results reveal that testing and culling strategies can induce complex transmission dynamics that can help us develop appropriate prevention and control measures for animal brucellosis.

Interactive web-based tool for evaluating the spread of bovine tuberculosis and brucellosis in Colombia

Background: Bovine tuberculosis (BTB) and brucellosis are associated with devastating losses in the livestock sector in Colombia and even in developed countries. Real-time disease surveillance is a key strategy to control and eradicate infectious disease outbreaks. Objective: To design an epidemiological tool for monitoring BTB and brucellosis in Colombia. Methods: An interactive platform for disease mapping of BTB and brucellosis during an observation period between years 2004 and 2019 was designed. Results: Our analysis showed that the provinces of Cundinamarca and Valle del Cauca are regions affected by BTB and brucellosis epidemics, respectively (p<0.001). Furthermore, increased case detection of BTB was reported in 2012 and brucellosis in 2019 (p<0.001). Conclusions: This epidemiological platform allows tracking BTB and tuberculosis hotspots, identifying trends over time, and provides useful information to animal health authorities for designing new strategies in control programs.

Astragalus polysaccharide strengthens the inflammatory and immune responses of Brucella suis S2-infected mice and macrophages

Brucella infection is one of the most serious zoonoses worldwide, affecting humans and domestic and wild animals. Astragalus polysaccharide (APS) is extracted from astragalus, which exhibits bioactive properties, including immunomodulation and anti-tumour and antiviral activity. The present study revealed that APS treatment promoted macrophage activation, the production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-12 and interferon-γ, and Brucella clearance in murine macrophages and spleens. APS treatment was also demonstrated to protect the integrity of macrophages during infection with live attenuated Brucella suis strain 2 (B. suis S2). The results from in vitro experiments were consistent with the findings from the in vivo study, showing the elevated secretion of TNF-α and nitric oxide in APS-treated murine peritoneal macrophages following B. suis S2 infection. The current study demonstrated the potential of APS in the control and treatment of Brucella infection, and the enhancement of host inflammatory and immune responses.

Spatial analysis to assess the relationship between human and bovine brucellosis in South Korea, 2005-2010

The first case of human brucellosis in South Korea was reported in 2002, and cases of human infection continue to occur. Although an association between human and bovine brucellosis has been identified, the spatial relationship has not been studied in South Korea. Here, we analysed the spatial patterns of human and bovine brucellosis retrieved from the human and veterinary surveillance data, as well as the spatial correlation between human and bovine brucellosis and associated factors that contribute to its occurrence. The risk of human brucellosis was analysed using a Bayesian spatial model with potential risk factors. Our results show that, for both human and bovine brucellosis, hotspots were clustered in the southeast regions of Korea, whereas coldspots were clustered in the northwest regions of Korea. Our study suggests that the risk of human brucellosis increases in rural regions with the highest risk of bovine brucellosis. Collaborative strategies between human and veterinary health sectors (e.g, public health intervention and region-specific eradication programs for bovine brucellosis) would reduce the burden of brucellosis in South Korea.

The impact of expanded brucellosis surveillance in beef cattle on human brucellosis in Korea: an interrupted time-series analysis

BACKGROUND

Korean surveillance program for bovine brucellosis was improved by extending it to beef slaughterhouses and by pre-movement testing of bulls on May 2005 (Intervention 1). The bovine brucellosis surveillance program was further extended to beef cattle farms with more than 10 heads of cattle on June 2006 (Intervention 2).

METHODS

To quantify the temporal relationship between bovine and human brucellosis, a time-series analysis was conducted using Korean national notification data reported between January 2004 and December 2014.

RESULTS

Our findings indicate that while during the pre-intervention phase (January 2004 to March 2005) there was no significant temporal relationship between the incidences of bovine and human brucellosis, significant temporal relationships were observed after Intervention 1 (June 2005 to June 2006, no lag, β = 0.57, p = 0.04), and Intervention 2 (July 2006 to June 2007, 1-month lag, β = 0.65, p = 0.03). Furthermore, significant changes in incidence in human were observed after Intervention 1 (β = - 0.17 per 10 million-people, p = 0.03) and Intervention 2 (β = - 0.19 per 10 million-people, p = 0.04).

CONCLUSIONS

These findings indicated the changes of a nationwide comprehensive surveillance programme targeting all cattle is required for effective reduction in the human population.

Brucellosis seroprevalence in ovine and caprine flocks in China during 2000-2018: a systematic review and meta-analysis

Background

Brucellosis remains one of the most common zoonotic diseases globally, with more than half million human cases reported annually. Brucellosis is an emerging and re-emerging disease in China since the 1990s. An infectious reservoir constituted by domestic animals with brucellosis, especially ovine and caprine herds, poses a significant threat to public health. The seroprevalence of brucellosis in sheep and goat flocks in a national context is unavailable so far. Therefore, we conducted this systematic review and meta-analysis to assess the overall status of brucellosis in sheep and goats in China in almost two decades.

Results

The pooled prevalence of brucellosis in ovine and caprine flocks in China increased in 2000–2009 (1.00%; 95% CI, 0.70–1.30) to 2010–2018 (3.20%; 95% CI, 2.70–3.60). The seroprevalence of brucellosis in sheep and goat flocks was higher in Eastern China, with 7.00% of positive rate, than that in any other region, especially Shandong province (18.70%). Brucellosis is highly endemic in some local regions. The high prevalence of brucellosis in agricultural regions is suggestive of a shift of geographic distribution. The pooled prevalence of brucellosis is higher in goat flocks than in sheep flocks in China.

Conclusions

The overall data in this meta-analysis demands comprehensive intervention measures and further surveillance to facilitate the control of brucellosis in livestock. Further studies aimed at evaluating the risk factors associated with spreads of brucellosis in domestic animals unaddressed so far, and sufficient epidemiological data is important to the exploration and understanding of the prevalent status of brucellosis throughout the country and to disease control.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1715-6) contains supplementary material, which is available to authorized users.

Animal brucellosis control or eradication programs worldwide: A systematic review of experiences and lessons learned

Brucellosis is one of the most common zoonoses worldwide, causing huge economic losses in the animal industry and posing a serious threat to human health. Although the World Health Organization (WHO) and World Organization for Animal Health (OIE) has recommended strategies or measures to control or eradicate brucellosis, only some developed countries have achieved freedom from animal brucellosis. In developing countries, brucellosis remains a serious problem, and the importance of its control has attracted little attention. The strategies and measures are difficult to implement effectively in countries with limited resources because the eradication of brucellosis is an expensive, time-consuming and labor-intensive project. Therefore, more effort is needed to explore the appropriate strategies and measures in developing countries. In this study, we collected the available publications regarding brucellosis control or eradication programs in different countries and areas, and summarized the main strategies and measures, supplementary measures, effects, and lessons learned during their implementation. Results showed that the freedom from animal brucellosis was only achieved in three countries among the 23 included countries and areas after the implementation of the programs, which had lasted several decades. Either alone or together, vaccination and test-and-slaughter programs can effectively reduce brucellosis prevalence. Supplementary measures involve a number of aspects, and their effective implementation is crucial to the success of disease control and cannot be ignored. While disease control or eradication requires extensive resources, some studies have shown that a well-designed and well-implemented disease control or eradication program is economically effective. Experience has revealed that even if significant results have been achieved, the project could not be terminated without careful consideration due to the potential for recurrence.

Tannic acid-mediated immune activation attenuates Brucella abortus infection in mice

Brucellosis is an emerging infectious disease affecting humans and animals. In this study, we investigated the in vitro and in vivo effects of tannic acid (TA) against Brucella abortus infection. After infection, F-actin polymerization and mitogen-activated protein kinases (MAPKs) (ERK 1/2 and p38α) phosphorylation were reduced in TA-treated cells compared with that in control cells. The mice were infected via an intraperitoneal route and were orally given TA or phosphate-buffered saline for 14 days. Spleen weights of the TA-treated and control mice were not different; however, splenic proliferation of B. abortus was significantly reduced in the TA-treated group. Immune response analysis showed that, compared with the control group, non-infected TA-treated mice displayed increased levels of interferon-γ (IFN-γ), monocyte chemoattractant protein-1 (MCP-1), and interleukin-10 at 3 days post-infection and a further increase in IFN-γ and MCP-1 at 14 days post-infection. In contrast, compared with the control group, infected TA-treated mice displayed elevated levels of IFN-γ at 3 days post-infection, which continued to increase at 14 days post-infection, as was also observed for tumor necrosis factor. Taken together, the results showing TA activation of cytokine production and inhibition of bacterial proliferation in the host highlight a potential use of TA treatment in the control of Brucella infection.

An Imported Case of Brucella melitensis Infection in South Korea

Brucellosis is a zoonotic infection that is usually transmitted from cattle to humans through ingestion of animal milk, direct contact with animal parts, or inhalation of aerosolized particles. In Korea, brucellosis seem to be transmitted through close contact with blood, fetus, urine, and placenta of domestic cow that has been infected by Brucella abortus, or inhalation of B. arbortus while examining or slaughtering cow. Brucella melitensis infection is rare in Korea and there have been no reported cases of B. melitensis originating from other countries until now. This report details a case of complicated brucellosis with infective spondylitis in a 48-year-old male construction worker recently returned from Iraq. Infection with B. melitensis was confirmed using 16s rRNA sequencing and omp31 gene analysis. The patient was successfully treated using a combination of rifampin, doxycycline, and streptomycin, in accordance with WHO guidelines. This is the first reported case of complicated brucellosis with infective spondylitis in Korea caused by B. melitensis originating from Iraq.

An evaluation of ELISA using recombinant Brucella abortus bacterioferritin (Bfr) for bovine brucellosis

To date, detection of antibodies against the lipopolysaccharide portion is the backbone of most serodiagnostic methods for brucellosis screening. However this pose a risk for false positive reactions related to other pathogens especially that of Yersinia enterocolitica O:9 which has the most prominent cross reactivity with Brucella spp. In this study, cloning and expression of Brucella abortus bacterioferritin (Bfr) was accomplished by PCR amplification into an expression vector system, and purification of a recombinant B. abortus Bfr (rBfr). The immunogenicity of rBfr was confirmed by Western blot with Brucella-positive bovine serum. To determine whether rBfr has a potential benefit for use in the serodiagnosis of bovine brucellosis, rBfr-based ELISA was performed. Interestingly, rBfr was able to detect anti-Brucella antibodies in positive sera in a dependent manner of TAT values but did not show an immunoreaction with negative samples. Particularly, average OD492 values at the lowest, medium and highest TAT titer levels were 1.4, 2.2 and 2.6-fold increase compared with the cutoff value, respectively. The accuracy, specificity and sensitivity of rBfr showed 89.09%, 93.6% and 85.33%, respectively. These findings suggest that rBfr might be a good candidate for serological diagnosis development of bovine brucellosis.