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.

Seropositivity of Leptospira spp. Antibodies among Febrile Patients Attending Outpatient Clinics in Mwanza, Tanzania: Should It Be Included in Routine Diagnosis?

Leptospirosis is a zoonotic neglected tropical disease with a worldwide distribution caused by the pathogenic spirochetes of the genus Leptospira. Despite being a widespread disease in tropical regions, it has never been considered in the routine diagnostic panel for febrile patients. This study determined seropositivity and factors associated with Leptospira antibodies among febrile adult patients in Mwanza, Tanzania. The cross-sectional study involving 296 febrile patients attending different outpatient clinics in Mwanza region was conducted between May and July 2019. Detection of Leptospira serovars antibodies was done using a microscopic agglutination test (MAT). Descriptive analysis was done using STATA version 13. The median age of the febrile patients was 32 (IQR: 24–45 years). Out of 296 patients, 36 (12.16%, 95%CI: 8–15) were seropositive for Leptospira antibodies. Common circulating serovars were Sokoine 28 (9.45%), followed by Lora 12 (4.05%) and Grippotyphosa 2 (0.67%). In the multivariable logistic regression analysis, the odds of being Leptospira seropositive were significantly higher with increased age (aOR: 1.03, 95%CI 1.00–1.07, p = 0.03). About one tenth of febrile patients in Mwanza were seropositive for Leptospira antibodies and this was significantly associated with age. With the decline of malaria fever in endemic areas, other causes of febrile illness like Leptospiral spp. should be considered in the routine diagnostic panel for febrile patients.

Existence of Similar Leptospira Serovars among Dog Keepers and Their Respective Dogs in Mwanza, Tanzania, the Need for a One Health Approach to Control Measures

This study investigated seroepidemiology of Leptospira serovars among the dog keepers and their dogs in the city of Mwanza, Tanzania. A total of 205 dog keepers and 414 dogs were tested for Leptospira antibodies using a microscopic agglutination test (MAT). The median age of the dog keepers was 26 (inter quartile range (IQR): 17-40) years and median duration of keeping dogs was 36 (IQR: 24-120) months. The seropositivity of Leptospira antibodies was (33/205 (16.1%, 95% CI: 11.0-21.1) among dog keepers and (66/414 (15.9%, 95% CI: 12.4-19.4) among dogs, p = 0.4745. Among the serovars tested (Sokoine, Grippotyphosa, Kenya, Pomona and Hebdomadis), the most prevalent serovar was Sokoine in both dog keepers and their dogs (93.9% (31/33) vs. and 65.1% (43/66), p = 0.009). Thirty-one out of thirty-three seropositive dog keepers (93.9%) had dogs positive for Leptospira antibodies with 28 (84.9%) having similar serovars with their respective seropositive dogs. Having tertiary education (AOR: 0.24, 95% CI: 0.07-0.84, p = 0.026) independently protected individuals from being Leptospira seropositive. More than three quarters of dog keepers had similar serovars as their dogs, necessitating one health approach to control measures in endemic areas.

Predominance of Brucella abortus antibodies among women with spontaneous abortion in the city of Mwanza: unrecognized link or coincidence?

OBJECTIVE

This study investigated the association of Brucella seropositivity and spontaneous abortions in human population in the city of Mwanza, Tanzania.

RESULTS

A comparative cross sectional study which used 148 sera from women with spontaneous abortion and 250 sera from full-term delivered women was conducted in July 2017. Detection of Brucella abortus and Brucella melitensis antibodies was done using slide agglutination test. Data were analyzed using STATA version 13 software. The median age of the study participants was 25 (interquartile range 21-30) years. The overall seropositivity of Brucella antibodies was significantly higher among sera from women with spontaneous abortion than full term delivered women; (86/148, 58.1%: 95% CI 50-66 vs. 65/250, 26%: 95% CI 18-33, P < 0.001). Seropositivity of B. abortus was significantly higher among sera from women with spontaneous abortion than full-term delivered women (31.8% vs. 10.8%, P < 0.001). Women with abortion had 3.59 odds of being brucella seropositive compared to full term women (OR: 3.59, 95% CI; 2.25-5.74, P < 0.001). Seropositivity of Brucella antibodies is significantly higher among women with spontaneous abortion than full-term delivered women necessitating a need to investigate the relationship between Brucellosis and adverse pregnancy outcomes.

Seropositivity of Brucella spp. and Leptospira spp. antibodies among abattoir workers and meat vendors in the city of Mwanza, Tanzania: A call for one health approach control strategies

INTRODUCTION

Brucellosis and leptospirosis are among neglected tropical zoonotic diseases particularly in the resource limited countries. Despite being endemic in these countries, there is paucity of information on its magnitude. This study investigated seropositivity of Brucella spp. and Leptospira spp., and associated factors among abattoir workers and meat vendors in the city of Mwanza, Tanzania.

METHODOLOGY

A community based cross-sectional study was conducted in Mwanza city from May to July 2017. Socio-demographic and other relevant information were collected. Detection of Brucella spp. and Leptospira spp. antibodies were done using slide agglutination test and microscopic agglutination test, respectively. Data were analyzed using STATA version 13 Software.

FINDINGS

A total of 250 participants (146 abattoir workers and 104 meat vendors) were enrolled with median age of 31 (IQR: 25-38) years. The overall, seropositivity of Brucella spp. antibodies was 48.4% (95% Cl: 42-54). Seropositivity of B. abortus was significantly higher than that of B. melitensis (46.0%, 95%Cl: 39-52 vs. 23.6%, 95% Cl: 18-28, P<0.001) while seropositivity of both species was 21.2% (95%Cl: 16-26). The seropositivity of Leptospira spp. was 10.0% (95% CI: 6-13) with predominance of Leptospira kirschneri serovar Sokoine which was detected in 7.2% of the participants. Being abattoir worker (OR: 2.19, 95% CI 1.06-4.54, p = 0.035) and long work duration (OR: 1.06, 95%CI: 1.01-1.11, p = 0.014) predicted presence of both B.abortus and B. melitensis antibodies. Only being married (p = 0.041) was significantly associated with seropositivity of Leptospira spp. Primary education was the only factor independently predicted presence of Brucella spp. antibodies among abattoir workers on sub-analysis of occupational exposure. None of factors were found to be associated with presence of Brucella spp. antibodies among meat vendors on sub-analysis.

CONCLUSION

Seropositivity of B.abortus antibodies among abattoir workers and meat vendors is high and seem to be a function of being abattoir worker, having worked for long duration in the abattoir and having primary education. In addition, a significant proportion of abattoir workers and meat vendors in the city was seropositive for Leptospira kirschneri serovar Sokoine. There is a need to consider 'one health approach' in devising appropriate strategies to control these diseases in the developing countries.

Predictors of specific anti-Brucella antibodies among humans in agro-pastoral communities in Sengerema district, Mwanza, Tanzania: the need for public awareness

Background

Human brucellosis remains to be a neglected zoonotic disease among agro-pastoral communities where livestock rearing is one of the main economic activities. This study was conducted in different agro-pastoral communities in Sengerema district, Mwanza, Tanzania, to determine seroprevalence and predictors of anti-Brucella antibodies, information that may influence public awareness on the risk factors and strategies to improve the diagnosis of brucellosis in developing countries.

Methods

A cross-sectional community-based study was conducted between July and September 2008 in ten villages of Sengerema district. Sociodemographic and other related information were collected using a standardized data collection tool. Detection of Brucella abortus and Brucella melitensis antibodies were done using rapid Brucella serum agglutination test. Data were analysed by using STATA version 11.0. Adjusted odds ratios (AOR) were calculated using multivariate logistic regression analysis.

Results

A total of 382 adults were enrolled with the median age of 30 (interquartile range 15–40) years. Males formed the majority of the participants 234 (61.5 %). Overall, seroprevalence of anti-Brucella antibodies was found to be 14.1 % (54/382, 95 % CI 10.6–17.5). Seroprevalence of B. melitensis was 11 % (42/382) while that of B. abortus was found to be 7 % (26/282), P = 0.0267. Co-infection of B. melitensis and B. abortus was observed in 3.6 % (14/382, 95 % CI 1.7–5.4) of participants. On a multivariate logistic regression analysis, male sex (AOR 3.2, 95 % CI 1.3–7.5, P = 0.007), touching goat placenta (AOR 2.54, 95 % CI 1.05–6.14, P = 0.012) and agro-pastoralist occupation (AOR 2.07, 95 % CI 1.01–4.24, P = 0.04) were found to predict B. melitensis infection. Males (AOR 3.07, 95 % CI 1.45–6.51, P = 0.003) and agro-pastoralists (AOR 2.98, 95 % CI 1.38–6.43, P = 0.005) were found to be predictors for specific anti-Brucella antibodies.

Conclusions

A significant proportion of the agro-pastoralist male population in agro-pastoral communities in Sengerema district is positive for anti-Brucella antibodies. With the decrease incidence of malaria fever, other causes of fever such as Brucella spp. should be considered of public health concern in Tanzania especially in agro-pastoral communities.