Brucella Infection Research Articles

BtpB inhibits innate inflammatory responses in goat alveolar macrophages through the TLR/NF-κB pathway and NLRP3 inflammasome during Brucella infection

Brucella species are infectious facultative intracellular pathogens. They have evolved multiple strategies to thwart immune responses and replicate in macrophages for chronic persistence in the host. As a Brucella effector, BtpB is transferred into target cells through the type IV secretion system. BtpB, a Toll/interleukin-1 receptor domain-containing protein, blocks host innate immune responses by interfering with Toll-like receptor signaling. However, the intracellular targets and their activated downstream pathways remain unclear. In this study, we constructed a strain of Brucella suis S2 with a deletion in the gene for BtpB, ΔbtpB, and the complemented strain, C-ΔbtpB with a restored copy of the btpB gene. The bacterial growth curves and stress resistance results showed that BtpB did not affect B. suis S2 growth. Infection of alveolar macrophages with WT and ΔbtpB strains showed that BtpB inhibited TLR2 and TLR4 expression and attenuated NLRP3 inflammasome activation. BtpB also attenuated secretion of the Brucella-induced proinflammatory cytokines, IL-1β, IL-6, and TNF-α, in alveolar macrophages while up-regulating IL-10 expression. In general, the results confirmed that BtpB specifically inhibits TLR2/TLR4 and disrupts NLRP3 signaling pathways to inhibit host immune responses in early Brucella infections.

Brucella Infection: A Major Public Health Concern

Zoonotic infectious diseases are common in societies where poverty is widespread, and where people rely on animals for their livelihood, that severely hinders livestock productivity and human health worldwide, particularly in the developing world and have been historically neglected by decision makers over the decades. WHO has identified a subgroup of eight endemic or neglected zoonotic diseasesanthrax, bovine tuberculosis, brucellosis, Taenia solium cysticercosis, hydatid disease, leishmaniasis, rabies, and human African trypanosomiasis.

Detection of Brucella infection in dairy buffaloes using conventional and molecular methods

Detection of Brucella infection in dairy buffaloes using conventional and molecular methods

Detection of Brucella Infections from Clinically Suspected Cases of Brucellosis in Garmain City- Sulaimani Province Kurdistan- Iraq

Brucellosis is a zoonotic disease transmitted between animals and humans by contaminated food, direct contact with an affected animal, or inhalation of aerosols. The research was for the period October 2019 to March 2020, 67vein blood samples of clinically suspected brucellosis (Malta fever) and 20 from healthy persons as control were tested. Control samples showed negative for brucellosis infection when serological testing was performed. while out of 67 suspected patients, 14 were significantly positive for Rose Bengal at titer (160), 39 positive for ELISA (37 for IgG and 2 for IgM). Out of 37 positive samples for IgG by ELISA, only seven samples were positive for Rose Bengal while two positive samples for IgM was negative for Rose Bengal.

Prevalence of Brucella infection and associated risk factors among children in livestock keeping communities of Morogoro, Tanzania

Brucellosis is among the most common bacterial zoonotic diseases worldwide. It is estimated that up to 500,000 new human cases occur each year. Brucellosis is a priority zoonosis in most East African countries. In Tanzania, the disease is one of six priority zoonoses, however, little disease burden information is available especially in children. Children are of particular interest especially in pastoral communities due to increased risk of exposure in their routine activities associated with handling of livestock and their products. This study investigated brucellosis exposure status and associated risk factors among non-febrile children in pastoral communities. A cross-sectional design was used involving a total of 361 non-febrile children of six months to 14 years old, randomly selected from households and schools. Risk practices were evaluated using focus group discussions among selected children and thematic analysis was performed. Serum samples were collected and analyzed using Rose Bengal Test (RBT) and indirect Enzyme-Linked Immunosorbent Assay (iELISA) in parallel. The overall seroprevalence of Brucella infection was 3.3% (95%CI, 2%-5%) determined by both RBT and iELISA. Risk practices observed and cited by children comprised of direct and indirect contact with animals and their products. These include: consumption of raw milk and their products, unhygienic handling of animals and their waste especially assisting cows during parturition. Girls/female respondents were more likely to test brucella positive than boys (male) respondents (2.23 OR, 95%CI 66%-754%). Brucellosis among non-febrile children in the study area was present at a relatively low prevalence. Risk practices for transmission of this zoonosis were also identified which included consumption of raw milk, contact with animals, their products and discharges including abortion materials which represent the basis for increased pathogen circulation in the area. General education on the epidemiology of brucellosis and prevention of infection spread should be provided to the community including children.

Brucellosis in pregnancy and its response to the changing immunoglobulin A: A prospective controlled study.

Objective:This study aimed to define the rare Brucella infection in pregnancy and its effects on immunoglobulins (Ig).Materials and Methods:This prospective study has conducted Brucella screening using the Rose Bengal test on pregnant and non-pregnant outpatients who did not show any specific Brucella symptoms. The immunoglobulin levels were measured using the enzyme-linked immunosorbent assay. The study group consisted of pregnant women who were at 20 weeks or below gestation and applied to our hospital outpatient clinic for routine check-ups. The control group consisted of healthy patients who applied for routine controls.Results:This study included a total of 584 participants, 293 of whom were controls and 291 were the study (pregnant) participants. The study revealed a 1.5% incidence of Brucella during pregnancy. In acute and chronic Brucella infection, lower levels of IgA response were observed in pregnant cases compared to the control group.Conclusion:Brucella infection is a disease that can cause fetal problems, especially in endemic areas. The role of the altered IgA response in pathologies that are associated with Brucella infection stands out as a new target for disease pathophysiology.

Seroprevalence of Brucella Infection in a Cohort of HIV-Positive Malawian Pregnant Women Living in Urban Areas.

Background: The seroprevalence of Brucella infection in sub-Saharan regions is high, and no recent data are available for Malawi, a country in which >60% of the population is involved in agropastoral activity. Aim: To evaluated the seroprevalence of Brucella in a cohort of HIV-positive pregnant women, living in an urban setting in Malawi. Methods: Sera of 201 pregnant women were tested for Brucella IgG. The Rose Bengal Plate Test and Serum Agglutination Tube test were used to determine antibody titer. Results: Five out of 201 (2.48%) women show positivity to Brucella, consistent with a past exposition to the infection. All five women delivered healthy infants, but two of them reported previous abortion/stillbirths, with a higher rate than those of the rest of the cohort (40% vs. 21.5%). Conclusions: This is one of the first reports of exposure of pregnant women to Brucella infection in Malawi, providing evidence of Brucella occurrence in an urban setting. Control programs should be introduced to reduce its impact on animal and human health.

HUMAN BRUCELLOSIS AMONG PYREXIA OF UNKNOWN ORIGIN CASES IN TWO TERTIARY HOSPITALS, IN SANA'A, YEMEN

Background and objectives: Brucellosis continues a most important health problem in numerous parts of the world and in the Middle East regions is a significant origin of acute febrile illness. This study was conducted to determine Brucella antibodies among patients with PUO, the association of brucellosis with demographic characteristics, identify clinical symptoms and risk factors for Brucella infection among PUO cases. Materials and Methods: This cross-sectional research study was conducted in two health institutions; Al-Jumhouri Hospital and Al-Thawra Hospital, between January 2021 to January 2022. The required data were gathered from each patient by using pre-defined standardized questionnaire. Five mL of sterile whole blood was collected from each patient and then tested for Brucella antibodies using a standard tubular agglutination test. The data were then analyzed using the statistical software Epi Info version 6. Results: Among the 241 PUO patients, females were 72.2% and males 27.8%. The mean ± SD for total age was 28.8±15.8 years. The rate of Brucella antibody among patients with PUO was 29%, females 78.6% higher than males by 21.4%. Clinical characteristics of PUO patients were persistent fever (36.9%), intermittent fever (63.1%), sweating (63.5%), shivering (61.4%), joint pain (78.4%), muscle pain (78.4%), back pain (74.7) back head pain (66.4%), headache (60.4%), weight loss (52.9%), body weakness (89.2%), loss of appetite (50.6%), and nausea (46.1%). The risk factors for brucellosis among the PUO patients was handling of animals during parturition (69.2%, OR=7, p<0.0001). Conclusion: These findings revealed a high prevalence of human brucellosis among PUO patients in Sana'a city and will becoming a serious problem that threats the health care system in Yemen. So, awareness programs should be provided to doctors, population about Brucella infection and its risk factors. Peer Review History: Received: 4 January 2022; Revised: 16 February; Accepted: 10 March, Available online: 15 March 2022 Academic Editor: Dr. Amany Mohamed Alboghdadly, Princess Nourah bint abdulrahman university, Riyadh, amalbgadley@pnu.edu.sa UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency. Received file: Reviewer's Comments: Average Peer review marks at initial stage: 6.0/10 Average Peer review marks at publication stage: 7.5/10 Reviewers: Dr. Bilge Ahsen KARA, Ankara Gazi Mustafa Kemal Hospital, Turkey, ahsndkyc@gmail.com Dr. Wadhah Hassan Ali Edrees, Hajja University, Yemen, edress2020@gmail.com Similar Articles: PATTERNS OF ANTIMICROBIAL RESISTANCE AMONG MAJOR BACTERIAL PATHOGENS ISOLATED FROM CLINICAL SAMPLES IN TWO TERTIARY’S HOSPITALS, IN SANA'A, YEMEN

MicroRNA-155 expression with Brucella infection in vitro and in vivo and decreased serum levels of MicroRNA-155 in patients with brucellosis

Infection with Brucella is characterized by the inhibition of host immune responses. MicroRNA-155 (miR-155) has been implicated in the immune response to many diseases. In this study, its expression during Brucella 16M infection of macrophages and mice was analyzed. Expression of miR-155 was significantly induced in macrophages at 24 h post infection. Further, an analysis of infected mice showed that miR-155 was inhibited at 7 and 14 days but induced at 28 days. Interestingly, this trend in induction or inhibition was reversed at 7 and 14 days in 16M△virB-infected mice. This suggested that decreased expression of miR-155 at an early stage of infection was dependent on intracellular replication. In humans with brucellosis, serum levels of miR-155 were significantly decreased compared to those in individuals without brucellosis and healthy volunteers. Significant correlations were observed between serum level of miR-155 and serum anti-Brucella antibody titers and the sweating symptom. This effect suggests that Brucella interferes with miR-155-regulated immune responses via a unique mechanism. Taken together, data from this study indicate that Brucella infection affects miR-155 expression and that human brucellosis patients show decreased serum levels of miR-155.

Brucellosis in Ethiopia: A comprehensive review of literature from the year 2000-2020 and the way forward.

Brucellosis is a zoonotic disease of considerable economic and public health significance globally. Despite the limited bacteriological evidence, a large number of serological works revealed that it is prevalent both in livestock and humans in Ethiopia. The current comprehensive review was carried out to provide apparent pooled seroprevalence (APS) estimates at individual animal and herd levels in livestock, and identify factors causing variability between studies conducted over the last two decades, show the spatial distribution, as well as summarizes Brucella species reported from livestock. It also provides APS of brucellosis in humans and evaluates the public health awareness of zoonotic brucellosis. In this review, systematic and synthetic review approaches were followed to summarize the available information. For the systematic review and meta-analysis, articles were selected based on predefined criteria. Data extracted from these articles were analysed using meta-analytical approaches to provide APS estimates and in-between study variations for humans and all livestock species considered. Sensitivity analyses and bias assessments were conducted using influence plot analysis and, Egger's and Begg's statistics along with funnel plots, respectively. Synthetic review approaches were used to summarize data on isolates and public health awareness. Pooled seroprevalence estimate of brucellosis at national level was 2.6% (95% CI: 2.2-3.0) in cattle, 4% (95% CI: 3.1-5.1) in goats, 3% (95% CI: 2.3-3.9) in sheep and 3% (95% CI: 2.4-3.7) in camels. At a herd level, 16.3% (95% CI: 12.9-20.5) of cattle, 12.1% (7.1-19.9) of goat, 13.3% (7.6-22.1) of sheep and 19.7% (13.8-27.4) of camel herds in the country had at least one seropositive animal. Cattle in the pastoral/agropastoral production systems had significantly higher (p<.05) APS compared to mixed crop-livestock and urban/peri-urban dairy production systems. Pooled seroprevalence of brucellosis in small ruminants (8.3%, 95% CI: 6.3-10.8) and camels (4.4%, 95% CI: 3.5-5.6) in Afar were significantly higher (p<.05) than in other regions. Reports conducted using ELISA and serial Rose Bengal plate test (RBPT)-ELISA had higher (p<.05) APS estimates than serial RBPT and complement fixation test. Brucella melitensis and B. abortus were reported from goats and cattle, respectively, from three available reports. The APS of brucellosis in humans was 5% (95% CI: 3.3-7.3). Public awareness of brucellosis was low (18.4%), while, practices that expose humans to Brucella infection were high. Scenario-based control interventions on regions and production systems using one health approach are suggested.

Platelet depletion does not alter the course of Brucella abortus infection in vivo

Brucellosis is a bacterial disease of animals and a zoonotic infection. Thrombocytopenia is a common outcome in long-lasting brucellosis in humans. Likewise, ex vivo experiments have shown that platelets may play a role in Brucella abortus infections. Following these reports, we explored the course of brucellosis in thrombocytopenic mice, using the non-toxic low-molecular-weight aspercetin protein that depletes platelets in vivo. Aspercetin does not induce systemic hemorrhage or inflammation, and when injected into mice, it generates a rapid dose-dependent drop in platelet counts without affecting central organs, disrupting hematological parameters, or the proinflammatory cytokine profile. Compared to the B. abortus infected control group, the infected thrombocytopenic mice did not show significant differences in the hematological profiles, pathological score, spleen, liver histopathology, or bacterial loads. Except for IL-6, which was higher in the infected thrombocytopenic mice, the TNF-α, IFN-γ and IL-10 did not significantly differ with the PBS-infected group. The results indicate that platelets do not play a significant role in modulating Brucella infection in vivo at the early stages of infection, which is commensurate with the stealthy strategy followed by Brucella organisms at the onset of the disease.

Brucella induces M1 to M2 polarization of macrophages through STAT6 signaling pathway to promote bacterial intracellular survival

Brucella are serious intracellular pathogens that parasitize macrophages and cause persistent infection in humans and animals. Although macrophages are an important bridge between natural and acquired immunity, their role in Brucella infection is not completely clear. Recently, studies have reported that Brucella can induce macrophage polarization, although the specific molecular mechanism involved is not known. Therefore, in the current study the replication ability of Brucella melitensis strain M5 (Brucella M5) was examined as well as its macrophage polarization and cytokine production, in a host. The role of Signal transducers and activators of transcription 6 (STAT6) in macrophage polarization induced by Brucella infection was also investigated. The results showed that Brucella M5 survived in vivo for a prolonged period of time and caused damage to the spleen and uterus tissues. The expression of type M2 cytokines was induced after Brucella M5 infection. Immunohistochemistry showed that STAT6 was upregulated in spleen and uterus tissues. At the cellular level, Brucella M5 induced macrophagetransformation from M1 to M2-type during the later stage of infection. When STAT6 was silenced, the polarization of M2-type was inhibited, and the intracellular survival rate of Brucella decreased significantly. In conclusion, these findings demonstrate that STAT6 is the key factor regulates M2 polarization of macrophages and promotes the intracellular survival of Brucella in the late stage of infection and provides an explanation of the mechanism responsible for persistent Brucella infection.

Seroprevalence, clinical profile and knowledge, attitudes, and practices (KAPs) of brucellosis in North India in patients with pyrexia of unknown origin and chronic joint pain

Introduction: Brucellosis is a significant but lesser-known cause of pyrexia of unknown origin (PUO) in India. Studies documenting the prevalence of Brucellosis in different parts of India are sparse and few. Clinicians thus usually don’t consider it in their differential diagnosis. This study assesses its prevalence in two groups: febrile patients with unknown etiology and individuals presenting with arthritis and/or joint pains. Knowledge, Attitude, and Practices (KAP) among clinicians about the disease was evaluated.Materials and Methods: This is a prospective study conducted at a tertiary care center of North India catering to urban, semi-urban, and rural populace. Ninety-two patients with fever of unknown origin, arthralgia, or similar constitutional symptoms were recruited in this study. Detailed clinical history was elicited from all patients as per predesigned proforma and a rigorous physical examination was conducted. Following primary screening to rule out malaria, enteric fever, and leptospirosis, secondary screening for Brucellosis was done by Rapid Screen Test (PUO screen) and IgM and IgG ELISA. A predesigned survey was used for assessing KAP among clinicians about Brucellosis.Results: Brucella infection was diagnosed in 27 (29.3%) cases. The most common symptoms among the patients apart from fever were arthralgia (77.8%), fatigue (70.8%), pallor (66.1%), headache (59.2%), backache (53.8%) and cough (33.3%). PUO screen is a specific test for brucellosis but lacks sensitivity. It detects acute cases but misses chronic cases. IgM ELISA being more sensitive should be used for confirmation. Low ODs point to chronic brucellosis which was confirmed by IgG ELISA. Normal CRP levels in patients with PUO and chronic joint pains should point to brucellosis. KAP revealed that 25% to 50% of doctors considered Brucella in their differential diagnosis of acute and chronic fever respectively while 10% Orthopedics considered it in cases of arthralgia.Conclusion: Our results highlight the significance of Brucella as a cause of PUO and arthralgia. Brucellosis is an underrecognized but important cause of pyrexia of unknown origin and chronic joint pain. It should be actively suspected, diagnosed, and treated.International Journal of Human and Health Sciences Vol. 06 No. 01 January’22 Page: 80-88

Brucellosis relapse causing thoracic aortic ulcers and aneurysm formation: a case report

BackgroundBrucellosis is an infectious disease caused by Brucella spp, which can involve the cardiovascular, digestive, and respiratory systems. Cardiovascular involvement is a rare occurrence, it has an extremely high mortality rate.Case presentationA 67-year-old Chinese man presented with thoracic aortic multiple ulcers and partial aneurysm formation that caused symptoms of left waist and left buttock pain. The man was admitted to our hospital due to abdominal aorta pseudoaneurysms 5 years ago. The diagnosis was made by thoracic computed tomography angiography (CTA), previous history, and positive culture of Brucella, and the patient was successfully treated by thoracic aortic covered stent-graft implantation and specific medical treatment.ConclusionsPeople who have a history of contact with cattle and sheep, should beware of the possibility of Brucella infection. If chest and abdominal pain occur, timely medical treatment is recommended, aortic aneurysm, the disease with a high risk of death, can be identified or excluded by CTA. Early treatment and prevention of disease progression are more beneficial to patients.

Brucella induces heme oxygenase-1 expression to promote its infection.

Brucellosis is a zoonotic and contagious infectious disease caused by Brucella spp, which causes substantial economic losses to animal husbandry and leads to severe public health problems. Brucella have evolved multiple strategies to escape host immunity and survive within host cells. Elucidating the immune evasion strategies during Brucella infection will facilitate the control of brucellosis. The host enzyme, heme oxygenase-1 (HO-1), is a multifunctional protein that functions during inflammatory diseases and microbial infections. However, how HO-1 functions during Brucella infection is rarely studied. In this study, we evaluated the role of HO-1 during Brucella infection. We found that Brucella infection induced HO-1 expression in macrophages. We further showed that HO-1 was regulated by PI3K, AMPK kinase, and nuclear erythroid-related factor 2 (Nrf2) in macrophages. Interestingly, knocking out HO-1 or inhibiting the activity of HO-1 significantly decreased Brucella intracellular growth. Inducing the expression of HO-1 by treatment with CoPP promoted Brucella intracellular growth. Mechanistic analyses indicated that the effect of HO-1 was not meditated by HO-1 metabolites, but by decreasing the production of reactive oxygen species (ROS), TNF-α, and IL-1β. Moreover, Brucella induced HO-1 expression in bone marrow-derived macrophages (BMDMs) and mice. When the expression of HO-1 was knocked down in BMDMs, the intracellular survival of Brucella was reduced. Furthermore, the induction of HO-1 by CoPP significantly increased bacterial loads in vivo. Thus, we demonstrated that Brucella induced HO-1 expression to promote its survival and growth in vitro and in vivo. This study also identified HO-1 as a novel innate immune evasion factor during Brucella infection.

Isolation of Brucella Melitensis and Evaluation of Serum Biochemical Changes in Camels: A Pilot Study to Prevent Human Brucellosis

Brucellosis is an infectious disease of livestock animals, which is reflected as one of the most severe public health issues worldwide. The main aim of this study is to isolate the B.melitensis and to examine the biochemical parameters in the serum of brucella infected and healthy camels. A total of 200 blood samples were collected from the camels of Shahaniya Governorate, Qatar. The Brucella isolation was done using different bacterial growth techniques. The status of blood metabolites and hepatic marker enzyme activities, kidney function markers, and mineral contents were estimated in the serum samples. Our findings revealed the probability of B.melitensis growth with 93-98%. The 34-50% of other species such as S.paucimobilis, A.lwoffii, A.salmonicida, and O.ureolytica were also noted in the serum of camels. In biochemical studies, the decreased status of glucose, total protein, albumin, and globulin in the serum of brucella-affected camels. The activities of AST, ALT, ALP, LDH, and GGT were up-regulated in the serum of brucella-infected camels. The levels BUN, creatinine, urea, creatine kinase, and bilirubin were also increased in the serum of brucella-affected camels. The calcium, magnesium, phosphorus, and iron were decreased in the brucella-infected camels. Here, we found the 93-98% probability of B.melitensis growth in the blood samples of camels. Furthermore, Brucella infection adversely altered the blood metabolites, liver function marker enzyme activities, kidney function markers, and mineral contents in the serum of camels.

Nucleomodulin BspJ as an effector promotes the colonization of Brucella abortus in the host.

Background Brucella infection induces brucellosis, a zoonotic disease. The intracellular circulation process and virulence of Brucella mainly depend on its type IV secretion system (T4SS) expressing secretory effectors. Secreted protein BspJ is a nucleomodulin of Brucella that invades the host cell nucleus. BspJ mediates host energy synthesis and apoptosis through interaction with proteins. However, the mechanism of BspJ as it affects the intracellular survival of Brucella remains to be clarified.ObjectivesTo verify the functions of nucleomodulin BspJ in Brucella's intracellular infection cycles.MethodsConstructed Brucella abortus BspJ gene deletion strain (B. abortus ΔBspJ) and complement strain (B. abortus pBspJ) and studied their roles in the proliferation of Brucella both in vivo and in vitro.ResultsBspJ gene deletion reduced the survival and intracellular proliferation of Brucella at the replicating Brucella-containing vacuoles (rBCV) stage. Compared with the parent strain, the colonization ability of the bacteria in mice was significantly reduced, causing less inflammatory infiltration and pathological damage. We also found that the knockout of BspJ altered the secretion of cytokines (interleukin [IL]-6, IL-1β, IL-10, tumor necrosis factor-α, interferon-γ) in host cells and in mice to affect the intracellular survival of Brucella.ConclusionsBspJ is extremely important for the circulatory proliferation of Brucella in the host, and it may be involved in a previously unknown mechanism of Brucella's intracellular survival.

Bovine Brucellosis: Epidemiology, Public Health Implications, and Status of Brucellosis in Ethiopia.

Brucellosis is a globally distributed zoonotic disease that causes serious problems in developing countries such as Ethiopia. Brucella abortus is the primary cause of brucellosis in cattle, and Brucella melitensis and Brucella suis also occasionally cause Brucella infection in cattle. Abortion and the retained fetal membrane are typical signs in females, whereas orchitis and bursitis are the known signs in male cattle. Brucellosis is typically transmitted to healthy cattle by direct or indirect contact with diseased cattle or their discharges. Humans can acquire brucellosis through the consumption of unpasteurized milk or milk products, and through contact with diseased cattle or their discharges. The occurrence of bovine brucellosis is affected by different factors related to the management system, host, and environmental factors. In Ethiopia, the occurrence of brucellosis is high in pastoral and mixed cattle management systems, wherever humans live closely with cattle and so have a higher probability of picking up the Brucella organism. The most suitable technique in the management of Brucella infection is the vaccination of young female cattle. Brucella abortus can also be eradicated by the isolation of diseased cattle, administration of immunizing agents, and test-and-slaughter methods. Therefore, it is important to implement applicable management techniques and to increase public awareness about the transmission of brucellosis, and further research should be conducted on brucellosis in high-risk groups.

Immune response and recent advances in diagnosis and control of brucellosis

Brucellosis is a zoonotic disease that has serious animal welfare and economic consequences worldwide. In mammals, this stealthy intracellular pathogen causes abortion and infertility, and in humans, it produces a terrible febrile illness that can progress into a long-term condition with serious implications. The pathogenicity of brucellae is based on their ability to survive and replicate in host cells, which allows them to escape from the immune system. The gold standard test for diagnosis, which demands competence, is still isolation and identification. Advancements in diagnostic procedures and screening of recently infected animals are required to achieve effective control. Despite their drawbacks, the most widely used vaccine strains to protect against Brucella infection and relevant abortions in cattle are B. abortus strains S19 and RB51 and in small ruminants is B. melitensis Rev1. However, there are no safe vaccine candidates for humans. Therefore, it is critical needs to improve vaccine production using advanced techniques such as subunit vaccines that are both effective and safe. Studying the overview of the Brucella immune response mechanism and advances in the diagnosis procedures allow more understanding of effective control strategies. The current review provides an overview on the immune response and updates on the diagnosis and control of brucellosis based on published literature on different search engines

Bibliographic Synthesis of Sero-Epidemiological Studies on Brucellosis in Domestic Ruminants (Cattle, Sheep and Goats) in Cameroon

Brucellosis is a neglected zoonosis in Cameroon but it remains enzootic in some agro-ecological zones of the country. This review aims to describe the current status of this disease in domestic ruminants in Cameroon. In order to know the current status of this disease, a systematic and synthetic review was conducted on brucellosis in domestic ruminants in Cameroon. Different types of studies with serological results were reported and considered. A total of 16 studies from 1980 to 2020 were included in this synthetic review of the literature. Most of the studies were cross-sectional descriptive studies (p = 0.12). However, there were also studies with simplified survey methods, modelling approaches, stratified non-probabilistic and probabilistic surveys. 5095 cases of brucellosis infection were identified in the literature, for which the laboratory diagnosis allowed confirmation of brucellosis in the different species (indirect or direct Elisa in the majority of studies (41%), followed by rose Bengal (26%)). In most cases cattle represent 80% of the most studied species. Associated with this, the northern part of Cameroon was the preferred study area at 70% followed by the west (27%) and the south (3%). The biological material of choice for the studies was serum (75%). In addition, other biological materials (15%) were used. This systematic review has identified the tools used over the last 40 years to diagnose brucella infection in ruminants in Cameroon. However, it highlights the need for continuous monitoring of the spatio-temporal evolution of abortive microorganisms on farms.