Seroprevalence of Brucella infection and associated factors among pregnant women receiving antenatal care around human, wildlife and livestock interface in Ngorongoro ecosystem, Northern Tanzania. A cross-sectional study

Seroprevalence and molecular detection of brucellosis among Pakistani women with spontaneous abortion

Background

Human brucellosis is a neglected disease transmitted to humans from animals such as cattle, goats, dogs, and swine. The causative agents are bacteria of the genus Brucella, intracellular pathogens usually confined to the reproductive organs of their animal hosts causing sterility and abortions. The objective of the study was to determine the seroprevalence of brucellosis among women with spontaneous abortions (SAW) and compare this seroprevalence with that of healthy pregnant women (HPW).

Methods

The case-control study was designed to determine the seroprevalence and molecular detection of brucellosis in women who suffered from spontaneous abortion and healthy pregnant women of the Haripur District of Pakistan. A total of 770 blood samples (n = 385 for each group) were collected from 9 public and 11 private hospitals in Haripur District from December 2021-March 2023. Data on demographic features, epidemiological variables, and risk factors were collected from each participant by structured questionnaires. Initial screening for brucellosis was performed by Rose Bengal Plate Test followed by qRT-PCR for molecular detection of the genus-specific BCSP-31 gene of Brucella.

Results

The study showed that anti-Brucella antibodies were more found in SAW 23.63% (91/385) than in HPW 1.29% (5/385). Brucella specific DNA was amplified in 89.01% (81/91) seropositive samples of SAW. Demographic features and risk factors such as age, urbanicity, socioeconomic status, education, occupation, and animal contact were found significantly associated with brucellosis (p ≤ 0.05). Consumption of unpasteurized raw milk (OR = 18.28, 95%CI: 8.16-40.94) was found highly concomitant with seroprevalence.

Conclusion

This study reports the first evidence of involvement of brucellosis in spontaneous abortions in women of Pakistan. The study can be used to develop strategies for risk management during pregnancy, to raise awareness for brucellosis, and develop control programs.

Immune Responses Potentially Involved in the Gestational Complications of Brucella Infection

Infection by Brucella species in pregnant animals and humans is associated with an increased risk of abortion, preterm birth, and transmission of the infection to the offspring. The pathogen has a marked tropism for the placenta and the pregnant uterus and has the ability to invade and replicate within cells of the maternal-fetal unit, including trophoblasts and decidual cells. Placentitis is a common finding in infected pregnant animals. Several proinflammatory factors have been found to be increased in both the placenta of Brucella-infected animals and in trophoblasts or decidual cells infected in vitro. As normal pregnancies require an anti-inflammatory placental environment during most of the gestational period, Brucella-induced placentitis is thought to be associated with the obstetric complications of brucellosis. A few studies suggest that the blockade of proinflammatory factors may prevent abortion in these cases.

High Seropositivity of Brucella melitensis Antibodies among Pregnant Women Attending Health Care Facilities in Mwanza, Tanzania: A Cross-Sectional Study

Background

Brucellosis is one of the most prevalent zoonotic neglected tropical diseases across the globe. Brucella melitensis (B. melitensis), the most pathogenic species is responsible for several pregnancy adverse outcomes in both humans and animals. Here, we present the data on the magnitude of B. melitensis antibodies among pregnant women in Mwanza, Tanzania, the information that might be useful in understanding the epidemiology of the disease and devising appropriate control interventions in this region. Methodology. A hospital-based cross-sectional study involving pregnant women was conducted at two antenatal clinics in Mwanza between May and July 2019. The pretested structured questionnaire was used for data collection. Blood samples were collected aseptically from all consenting women followed by the detection of B. melitensis antibodies using slide agglutination test. Descriptive data analysis was done using STATA version 17.

Results

A total of 635 pregnant women were enrolled with the median age of 25 (interquartile range (IQR): 16-48) years and median gestation age of 21 (IQR: 3-39) weeks. Seropositivity of B. melitensis antibodies was 103 (16.2 (95% CI:13.3-19.1)). On the multivariate logistic regression analysis, as the gestation age increases, the odds of being seropositive decreases (aOR:0.972 (95% CI: 0.945-0.999), P = 0.045). Furthermore, being a housewife (aOR:3.902 (95% CI:1.589-9.577), P = 0.003), being employed (aOR:3.405 (95% CI:1.412-8.208), P = 0.006), and having history of miscarriage (aOR:1.940 (95% CI:1.043-3.606), P = 0.036) independently predicted B. melitensis seropositivity among pregnant women in Mwanza.

Conclusion

High seropositivity of B. melitensis was observed among employed and housewife pregnant women in Mwanza. This calls for the need of more studies in endemic areas that might lead to evidence-based control interventions.

Women’s thirty-year contribution to cheetah conservation: An insight into volunteer-based conservation program supported by female scientists

Women make up a small percentage of the scientific community, including conservation. Today, conservation efforts are vital for the survival of many species, however there is a gender bias within the conservation field. Encouraging more women into conservation could be a key to increasing efficiency and success in conservation goals of organizations and governments. Here we investigate the long running Earthwatch, working guest and intern volunteer programs of the Cheetah Conservation Fund (CCF) to understand women’s involvement with volunteer based conservation, and questionnaire data to understand women’s contribution to conservation after volunteering and what challenges women face in conservation. Our results showed there was significantly more female volunteers than male volunteers (p-value <0.000) and on average, females contributed to 73.7% of the volunteer population annually. Volunteer’s age at time of volunteering varied between the three volunteer programs. Women’s motivations for volunteering and challenges that women face in conservation was dependent on the volunteers’ age. CCF’s holistic approach to conservation, volunteers’ love for cheetahs and ability to gain practical skills were the leading motivations why women volunteered with CCF. Many (87%) of the female interns said volunteering was a means of helping them gain employment. Women’s credibility, family responsibility and personal safety were the main challenges that women face working in conservation today. Addressing gender disparities in every stage of career progression will lead to overall improved conservation outcomes.

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.

Brucellosis testing patterns at health facilities in Arusha region, northern Tanzania

BACKGROUND

Brucellosis is listed as one of six priority zoonoses in Tanzania's One Health strategic plan which highlights gaps in data needed for the surveillance and estimation of human brucellosis burdens. This study collected data on current testing practices and test results for human brucellosis in Arusha region, northern Tanzania.

METHODS

Retrospective data were extracted from records at 24 health facilities in Arusha region for the period January 2012 to May 2018. Data were captured on: the test reagents used for brucellosis, procurement and testing protocols, the monthly number of patients tested for brucellosis and the monthly number testing positive. Generalised linear mixed models were used to evaluate relationships between health facility characteristics and the probability that brucellosis testing was conducted in a given month, and the proportion of individuals testing positive.

RESULTS

Four febrile Brucella agglutination tests were used widely. The probability of testing for brucellosis in a given month was significantly associated with an interaction between year of testing and facility ownership. Test probability increased over time with more pronounced increases in privately owned as compared to government facilities. The proportion of individuals testing positive for brucellosis was significantly associated with facility type and district, with individuals tested in hospitals in Meru, Monduli and Ngorongoro districts more likely to test positive.

CONCLUSIONS

Febrile Brucella agglutination tests, known for their poor performance, were the mainstay of brucellosis testing at health facilities in northern Tanzania. The study indicates that historical data on human brucellosis in Arusha and other regions are likely to provide an inaccurate measure of true disease burden due to poor performance of the tests used and variation in testing practices. Measures to address these identified shortcomings could greatly improve quality of testing and surveillance data on brucellosis and ultimately inform prevention and control of this priority disease.

Occurrence and risk factors of brucellosis among domestic animals: an artificial neural network approach

Brucellosis is a zoonotic infectious disease with a worldwide distribution. This cross-sectional study aimed to determine the occurrence of Brucella in milk and blood samples of ruminants and the importance factors associated with animal brucellosis in Eastern Iran. A total of 200 paired samples, including blood (100) and milk (100), were obtained from the goats, sheep, and cows in Eastern Iran. Serum agglutination (SAT) and 2-mercapto ethanol (2-ME) tests were performed on the sera. A multiplex-polymerase chain reaction (m-PCR) assay was performed to identify the following species of Brucella, including B. abortus biovar 1, 2, 4, 3b, 5, 6, and 9, B. abortus S19, B. melitensis, and B. melitensis Rev.1 vaccine strain. B. abortus RB51 vaccine strain was also investigated in a second PCR assay. Risk factors for infection with Brucella spp. including the effect of abortion, contact with the wild animals, herd type, age, and previous vaccination in predicting blood contamination with B. abortus biovar 1, 2, and 4 were modeled by use of the artificial neural network. A total of 23 samples were seropositive regarding SAT and 2-ME tests. In total, B. abortus was detected in 35% and 15% of blood and milk samples, respectively, by the m-PCR assay. One sample of each of milk and blood was detected to have B. melitensis. Some samples were simultaneously contaminated with two Brucella species or two biovars of B. abortus. B. abortus S19 and B. melitensis Rev.1 vaccine strains were also detected in milk and blood samples. The sensitivity and specificity of the ANN model were 81% and 62%, respectively. In conclusion, B. abortus had higher frequency than B. melitensis in blood and milk samples. ANN determined herd type, previous vaccination, and age of the animal as the largest predictors of blood contamination with B. abortus.

Circulating Brucella species in wild animals of the Serengeti ecosystem, Tanzania

BACKGROUND

Brucellosis is a bacterial zoonosis of public health and economic importance worldwide. It affects a number of domestic animals, wild animals and humans. Human brucellosis originates from either livestock or wildlife. The species of Brucella circulating in wild animals in Tanzania is largely unknown due to insufficient surveillance. This study was carried out to identify Brucella species found in selected wildlife hosts in the Serengeti ecosystem.

METHODOLOGY

The study used a total of 189 archived samples that were obtained from cross-sectional studies previously conducted between 2000 and 2017 in the Serengeti ecosystem in Tanzania. Whole blood, serum and amniotic fluid collected from buffalos, lions, wildebeest, impala, zebra and hyena were available for DNA extraction. Multiplex polymerase chain reaction for B. abortus, B. melitensis, B. ovis and B. suis (AMOS PCR) and quantitative real-time PCR (qPCR) targeting the bcsp31 and IS711 genes for Brucella genus detection and the IS711 targets alkB for B. abortus and BMEI1162 for B. melitensis were used to detect Brucella strains.

RESULTS

Out of the 189 samples tested, 12 (6.35 %) and 22 (11.6 %) were positive to AMOS-PCR and qPCR, respectively. Most of the positive samples were from lions (52.6 %) and buffaloes (19.6 %). Other animals that were positive included: wildebeest (13.6 %), impala (13.6 %), zebra (4.5 %) and hyena (4.5 %). Out of 22 positive samples, 16 (66.7 %) were identified as B. abortus and the other six samples did not amplify for neither B. abortus nor B. melitensis.

CONCLUSIONS

The detection of Brucella DNA in archived wild animal samples shows testing potential of samples collected from this population. The zoonotic species B. abortus and B. melitensis detected in wild animals have previously been reported in livestock and humans in the region. The findings suggest that, due to the contact network, some of the identified wild animal hosts in this study could be reservoirs for infections in domestic animals and humans within the Serengeti ecosystem while others are likely dead-end hosts. One Health control strategies and continuous surveillance programs in other wildlife reserved areas should be implemented to help predicting transmission in livestock and humans in the region.

Performance characteristics and costs of serological tests for brucellosis in a pastoralist community of northern Tanzania

The control of brucellosis across sub-Saharan Africa is hampered by the lack of standardized testing and the use of tests with poor performance. This study evaluated the performance and costs of serological assays for human brucellosis in a pastoralist community in northern Tanzania. Serum collected from 218 febrile hospital patients was used to evaluate the performance of seven index tests, selected based on international recommendation or current use. We evaluated the Rose Bengal test (RBT) using two protocols, four commercial agglutination tests and a competitive enzyme-linked immunosorbent assay (cELISA). The sensitivity, specificity, positive predictive value, negative predictive value, Youden's index, diagnostic accuracy, and per-sample cost of each index test were estimated. The diagnostic accuracy estimates ranged from 95.9 to 97.7% for the RBT, 55.0 to 72.0% for the commercial plate tests, and 89.4% for the cELISA. The per-sample cost range was $0.69-$0.79 for the RBT, $1.03-$1.14 for the commercial plate tests, and $2.51 for the cELISA. The widely used commercial plate tests performed poorly and cost more than the RBT. These findings provide evidence for the public health value of discontinuing the use of commercial agglutination tests for human brucellosis in Tanzania.

Formyl peptide receptor 2 (FPR2) antagonism is a potential target for the prevention of Brucella abortus 544 infection

Here, we explore the potential role of formyl peptide receptor 2 (FPR2) during Brucella abortus infection. FPR2 manipulation affected B. abortus internalization but not its growth within macrophages. During the activation of FPR2 induced by its agonist AGP-8694, a high level of Brucella uptake was accompanied by an increase in ERK phosphorylation, while intracellular survival at 24 h postincubation was observed to be associated with slightly reduced nitrite accumulation but augmented superoxide anion production. Attenuated secretion of IL-6 and IL-10 were observed 48 h postincubation in the bone marrow-derived macrophages (BMDMs) treated with the FPR2 antagonist WRW4. An opposite pattern of bacterial uptake was observed upon treatment with the FPR2 antagonist, but no significant changes in the activation of MAPKs or the production of nitrite or superoxide anion were observed. Interestingly, AGP-8694 treatment of mice did not lead to differences in spleen or liver weight but slightly enhanced bacterial proliferation was observed in the spleen. Although the weights of the spleen or liver did not differ, WRW4 treatment led to reduced bacterial proliferation in the spleen. Furthermore, FPR2 antagonist treatment was associated with high serum levels of the proinflammatory cytokines IL-12, TNF-α, IFN-γ and MCP-1, while the production of TNF-α was inhibited in AGP-8694-treated mice. IL-6 and IL-10 levels were slightly increased in AGP-8694-treated mice at 24 h postinfection. Our findings demonstrated the contribution of FPR2 via manipulating this receptor using its reported agonist AGP-8694 and antagonist WRW4 in both in vitro and in vivo systems. Although activation of the receptor did not consistently induced Brucella infection, FPR2 inhibition may be a promising strategy to treat brucellosis in animals which encourages further investigation.