Association of brucellosis to abortions in humans and domestic ruminants in Kagera ecosystem, Tanzania

Abstract

Brucellosis is a worldwide zoonotic disease of socio‐economic importance. Understanding the association of this disease with pregnancy outcome has the potential of contributing to the reduction of its reproductive burden in humans and animals among pastoral communities in Tanzania. A prospective cohort study was conducted in Kagera Region on pregnant women (n = 76) and gravid ruminants (121 cattle, 125 goats and 111 sheep). Exposed and non‐exposed groups to brucellosis were followed for 6 months (from 15 November 2017 to 15 April 2018). Sera were collected and analysed using Rose Bengal Test (RBT) and Fluorescence polarization assay (FPA) test. Measures of effect, univariable and multivariable logistic regression analyses were computed. Positivity to both RBT and FPA tests was 21% (95% CI: 12.5–32) in pregnant women and 5% (95% CI: 3.1–8) in gravid ruminants. Among aborted cases, four women (out of nine), two cows (out of seven), two goats (out of 26) and zero sheep (out of 11) were positive to brucellosis. The abortion rate in humans and ruminants was 11.8% and 12.3%, respectively. Seropositivity to brucellosis was similar in aborted and non‐aborted cases in humans (p = .08) and in ruminants (p = .2). At the population level, brucellosis was associated with abortions (population attributable risk: PAR) at 3.5% in pregnant women and at 0.5% in gravid ruminants in the study area. Infections to brucellosis were increased in exposed pregnant women (OR = 19; 95% CI: 1.8–203, p = .01) and in cattle (OR = 11; 95% CI: 1.3–88, p = .02). There is an indication that brucellosis could be contributing to abortions in pregnant women and domestic ruminants Kagera Region. Molecular tools could support more the results from serological tests to avoid cross‐reaction with other pathogen agents. Control of brucellosis in animals is likely to reduce the threat of abortions in humans.

A 10-year retrospective comparative analysis of the clinical features of brucellosis in children and adults

“…In this study, 2 children and 34 adults were diagnosed with orchiepididymitis. According to previous studies, women infected with Brucella suffer from oophoritis, salpingitis, endometritis and others complications, resulting in abortion [13] although the above were not reported in this study. Understanding the damage caused to the reproductive system is helpful in reducing adverse outcomes in pregnancy.…”

Molecular characterization of Brucella species detected in humans and domestic ruminants of pastoral areas in Kagera ecosystem, Tanzania

“…This study detected Brucella in sera from abortive woman, cow and goat. Although there was a failure to detect Brucella from a limited sample size of aborted materials, the detection of Brucella from sera of aborted individuals could raise the same suspicions regarding the contribution of brucellosis to reproductive failure in this pastoral area as reported earlier (Ntirandekura et al, 2020). The failure to detect Brucella species in aborted materials could have been associated to the transport medium used (liquid nitrogen), long time for conservation of samples before analysis (9 months) and the low DNA concentration among other factors.…”

“…The samples were collected during previous cross‐sectional and prospective cohort studies conducted in Ngara and Karagwe districts (Figure 1) in June 2017 (personal communication) and November 2017‐ April 2018 in Kagera region, Tanzania (Ntirandekura, Matemba, Kimera, Muma, & Karimuribo, 2020). Five millilitres of venous blood were firstly taken from humans going for malaria checking (July 2017) (personal communication) and from cattle, goats and sheep in the same villages.…”

“…Five millilitres of venous blood were firstly taken from humans going for malaria checking (July 2017) (personal communication) and from cattle, goats and sheep in the same villages. Secondly, 5ml of venous blood were taken from pregnant women attending antenatal care (November 2017‐April 2018) and gravid ruminants in the same pastoral area (Ntirandekura et al., 2020). Each blood samples reacting to the rose Bengal, C‐Elisa and FPA tests was aliquoted and kept at −20°C for molecular analysis.…”

A Retrospective Survey of the Abortion Outbreak Event Caused by Brucellosis at a Blue Fox Breeding Farm in Heilongjiang Province, China

“…Similarly, a previous study reported that brucellosis was found in a fox farm ( 27 ). Molecular tools can support the results from serological tests to avoid cross-reaction with other pathogens ( 28 ). AMOS-PCR results showed the presence of this special 731 bp band in many aborted fetuses' samples.…”