Epidemiological investigation of brucellosis in breeding female cattle under the traditional production system of Jimma zone in Ethiopia

Using participatory epidemiology to investigate the causes of cattle abortion in Southwest Ethiopia

Cattle abortion, stemming from both infectious and non-infectious causes, lead to notable financial setbacks in the cattle industry. Between October 2020 and October 2021, an epidemiological investigation took place in Southwest Ethiopia. The objective was to determine the magnitude and seasonal occurrence of the presumed causes of cattle abortion. Information for this research was collected through 30 group discussions, each involving 8-12 participants. Various participatory epidemiological tools, including semi-structured interviews, pairwise ranking, matrix scoring, proportional piling, and seasonal calendars, were employed in the designated areas. By employing the pairwise ranking approach, the relative significance of presumed causes contributing to cattle abortion was established. The identified major presumed causes of cattle abortion, listed in increasing order of importance, were blackleg, foot-and-mouth disease, pasteurellosis, lumpy skin disease, listeriosis, trypanosomosis, Q fever, leptospirosis, and brucellosis. Participants identified brucellosis (6.1%), leptospirosis (6.0%), and Q-fever (5.7%) as the primary presumed causes of abortion, determined through proportional piling. Matrix scoring analysis indicated a robust agreement (W = 0.464-0.989; P < 0.001) among different informant groups regarding both the presumed causes of abortion and the associated clinical signs. Brucellosis and Q-fever were perceived to be more prevalent during the dry season, while leptospirosis, listeriosis, and lumpy skin disease were associated with the wet, hot, and rainy seasons. However, Pasteurellosis, blackleg, and physical/mechanical factors were deemed to be consistently encountered causes of abortion throughout the year. The patterns of seasonal occurrence of suspected abortion causes were widely acknowledged across informant groups (W = 0.977-0.863; P < 0.001). Local practices involving herbal remedies and traditional methods were employed by participants to manage cattle abortion. Moreover, the results underscore the necessity for additional laboratory research to pinpoint the exact causes of abortion in the study areas.

Seroprevalence of Coxiella burnetii, Leptospira interrogans serovar hardjo, and Brucella species and associated reproductive disorders in cattle in southwest Ethiopia

In Ethiopia, Coxiella burnetii, Leptospira Hardjo, and Brucella spp are recognized as the primary factors contributing to cattle reproductive issues. A cross-sectional study was conducted in southwest Ethiopia from October 2020 to October 2021 to assess the risk of reproductive disorders associated with L. Hardjo, Coxiella burnetii, and Brucella spp. Moreover, the study aimed to identify the factors associated with reproductive disorders. Using an indirect ELISA, antibodies against these pathogens were observed in serum samples collected from 461 cattle. We employed multivariable random effect logistic regression analysis to identify potential risk factors associated with reproductive disorders in cattle. The study areas showed a prevalence of 25.16 % (95 % CI: 21.20-29.12) for cattle reproductive disorders. The presence of Leptospira Hardjo (OR = 2.9, 95 % CI: 1.17-4.02) and Coxiella burnetii (OR = 3.0, 1.49-5.94) antibodies was associated to the occurrence of cattle reproductive disorders. Seropositivity to pathogens B. abortus, C. burnetii, and L. Hardjo, along with co-infection of all three, showed association with cattle abortion. The presence of L. Hardjo seropositivity and co-infection with C. burnetii were related to dystocia in cattle. Cattle with retained fetal membranes were associated with co-infection seropositivity to these pathogens. Additionally, B. abortus seropositivity was linked to cases of repeated breeding in cattle. Age, breeding practices, and dog access to cattle showed associations with reproductive disorders, with odds ratios of 2.3 (95 % CI: 2.03-4.69), 2.9 (95 % CI: 1.83-4.82), and 6.5 (95 % CI: 1.04-2.53) respectively. This research indicates that Brucella abortus, Coxiella burnetii, and Leptospira Hardjo, which are responsible for severe zoonotic diseases, have a substantial negative impact on cattle production by causing reproductive disorders. To address the transmission of these diseases, it is essential to implement effective mitigation strategies and enhance public awareness. Additional investigation is necessary to identify and understand the factors contributing to cattle reproductive disorders in the specified area.

Herd and animal level seroprevalence and associated risk factors of bovine brucellosis in different agro-ecologies of southwest Ethiopia

Brucellosis is a zoonotic infection that commonly affects cattle in Ethiopia, causing significant negative economic impact. A cross-sectional study was carried out between November 2020 and November 2021 in southwest Ethiopia to determine the seroprevalence of brucellosis and its associated risk factors in cattle herds. Blood samples were taken from 461 randomly selected cattle to test for the presence of Brucella antibodies using the Rose Bengal Plate test, with positive serum confirmed through the complement fixation test. A multivariable random effect logistic regression analysis was used to identify potential risk factors for Brucella seropositivity. The study found 7.14% (95% CI: 4.44-9.01) seroprevalence at the animal level and 12.23% (95% CI: 6.52-16.05) at the herd level based on the complement fixation test. Age (OR = 6.9, 95%CI: 1.83-15.97), herd size (OR = 3.66, 95%CI: 1.39-9.61), introducing new animals (OR = 2.72, 95%CI: 1.17-6.29), management system (OR = 12.2, 95%CI: 1.53-26.80), species composition (OR = 4.24, 95%CI: 1.51-11.91), and abortion (OR = 7.1, 95%CI: 1.93-15.39) were found to be associated with Brucella seropositivity. The analysis also revealed two risk factors for Brucella infection at the herd level, including herd size (OR = 3.4, 95% CI: 1.05-10.68) and species composition (OR = 3.1, 95% CI: 1.20-7.88). The presence of Brucella antibodies in cattle highlights the need for increased awareness and measures to mitigate the identified risk factors of the disease to prevent its spread. Furthermore, further studies are necessary to investigate the zoonotic transmission of brucellosis to humans and its role in cattle reproduction disorders in the study area.

Occurrence and Risk Factors of Brucellosis in Commercial Cattle Farms from Selected Districts of the Eastern Coast Zone, Tanzania

Brucellosis is a disease of major socio-economic importance worldwide, particularly in low-income countries. This retrospective study aimed to estimate seroprevalence and risk factors associated with brucellosis in commercial cattle farms in the eastern coast zone of Tanzania (ECZT). A total of 1,052 serum samples collected from 20 commercial farms were subjected to rose bengal plate test (RBPT) and indirect enzyme-linked immunosorbent assay (i-ELISA). Descriptive analysis was employed to determine frequencies and proportions. To establish risk factors, a multivariate logistic regression analysis was carried out using a backward elimination procedure, following a univariate analysis, with 0.1 set as a cut-off point for the selection of putative risk factors. Agreement between RBPT and i-ELISA was determined using a Kappa coefficient (κ). The overall animal-level seroprevalence was 25.9% based on i-ELISA. Logistic regression analysis revealed that odds of infection were significantly higher in females (OR = 1.8, 95% CI: 1.2-2.5, p = 0.002) and in young animals than in adults (OR = 3.6, CI: 2.1-6.2, p < 0.001). In addition, odds of infection were higher during the wet season (OR = 3.4, CI: 3.2-5.2, p < 0.001), in cattle reared in rural farms (OR = 4.8, CI: 2.0-11.5, p < 0.001), in cattle reared in areas, not in contact with wildlife (OR = 2.9, CI: 1.4-2.3, p = 0.004), and in medium-sized farms (OR = 12.5, CI: 6.9-22.9, p < 0.001). These findings confirm that bovine brucellosis was prevalent among commercial cattle farms in the ECZT, posing a serious public health concern to the community living in these settings. The one health approach should be adopted for effective control of brucellosis.

Antimicrobial Profiles and Conventional PCR Assay of Shiga Toxigenic Escherichia coli O157:H7 (STEC) Isolated from Cattle Slaughtered at Bedele Municipal Abattoir, South West Ethiopia

Background

Shiga toxin producing Escherichia coli O157:H7 (STEC) is considered the most prevalent food borne pathogen that has gained increasing attention worldwide in recent years.

Methods

A cross-sectional study was carried out at Bedele Municipal abattoir on cattle that were reported healthy from detailed ante-mortem inspections and having various body conditions scores. A total of 516 samples were collected and examined after enriched in modified peptone water. Following an enrichment, the samples were plated onto MacConkey agar and then onto Eosin methylene blue agar. Finally after a few similar procedures, 14 E. coli O157:H7 (STEC) isolates were confirmed through latex agglutination test. The collected data were analyzed using SPSS version 20 statistical software.

Results

This study finding revealed that the overall prevalence of E. coli O157:H7 out of 516 samples was found to be 2.7%. However, on sample type basis, the prevalence of E. coli O157:H7 from feacal samples, carcass swabs, butcher hand swabs and knife swabs were 4.7%, 3.3%, 1.1% and 1.1%, respectively. It was also found that that the prevalence of E. coli O157:H7 was significantly affected by age groups of slaughtered cattle (p<0.05). Moreover, in vitro antimicrobial susceptibility test result on average showed that almost all of E. coli O157:H7 isolates were highly susceptible to kanamycin and no resistance was shown to ciprofloxacin and gentamicin. Finally, the conventional PCR detection of stx1, st2 and hylA genes revealed that only 21.4% and 14.3% were found to contain stx1 and hylA genes respectively.

Conclusion

To wrap up, this study showed that Shiga toxin producing E. coli O157:H7 (STEC) isolates were found with almost low overall prevalence rate from all sample sources in this study site. Therefore, improving abattoir facilities and slaughter house workers' personal hygiene are recommended to curtail E. coli O157:H7 meat contamination in this abattoir.

Recombinant protein G/Au nanoparticles/graphene oxide modified electrodes used as an electrochemical biosensor for Brucella Testing in milk

In this study, a simple label-free biosensor for Brucella was constructed, which based on the screen-printed carbon electrode (SPCE) modified by Recombinant protein G/gold nanoparticles/graphene oxide (RpG/Au/GO). The impedance responses of the proposed biosensor were measured by electrochemical AC impedance method in Brucella antigen gradient concentration solutions. The results showed that the linear range of this biosensor was from 1.6 × 102 CFU/mL to 1.6 × 108 CFU/mL with the minimum detection limit of 3.2 × 102 CFU/mL (S/N = 3). Moreover, the biosensor for Brucella detection possessed acceptable reproducibility with a relative standard deviation of 5.15% and acceptable stability with a relative standard deviation of 4.68%. The spiked recovery rate in actual pasteurized milk samples was more than 92%. Therefore, the developed biosensor exhibits excellent prospects in the selective quantification detection of Brucella abortus.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05544-8.

Cross-Sectional Study of Seroprevalence and Associated Risk Factors of Bovine Brucellosis in Selected Districts of Jimma Zone, South Western Oromia, Ethiopia

Bovine brucellosis is one of the most widespread but neglected zoonotic diseases in developing countries where it is an endemic and growing problem causing public health impacts. Developing a cost-effective control strategy of the disease can only be guaranteed by knowledge of the disease epidemiology that defines its risk profiles. Hence, this study was designed to evaluate epidemiological aspects of bovine brucellosis in selected districts of Jimma zone. A cross-sectional study with multistage sampling techniques was conducted on 424 cattle to evaluate its seroprevalence. Likewise, 114 households were included for the investigation of risk factors. SPSS version 20 for data analysis and C-ELISA test for antibody detection were used. Moreover, the chi-square test for univariable analysis and logistic regression model for multivariable analysis were employed to assess association between seropositivity and risk factors. From this study, 3.3% (95% CI: 1.82-5.48) and 12.3% (95% CI: 6.88-19.75) seroprevalence of the disease was detected with the highest proportion found at Kersa district (6.5 (95% CI: 1.37-17.90) and (21.4 (95% CI: 4.66-50.80)) followed by Seka Chokorsa (1.76 (95% CI: 0.37-5.07) and (6.7 (95% CI: 1.40-18.27)) and Mana (1.75 (95% CI: 0.21-6.20) and (7.1 (95% CI: 0.88-23.50)) at individual animals and herd levels, respectively. Cattle of poor body condition, pregnant, and cows with history of abortion and repeat breeding were found 4.8 (95% CI: 2.00-22.74), 4.3 (95% CI: 1.43-13.04), 3.3 (95% CI: 1.07-10.21), and 2.7 (95% CI: 1.86-8.15) times more likely seropositive than their counterparts, respectively. Besides these, mixed feeding style was highly associated with seropositive reactors than separate feeding (AOR = 8.3; 95% CI: 1.76-38.99). These findings depicted substantial areas to be addressed in implementation of appropriate and immediate control actions and establishment of intervention mechanisms of bovine brucellosis.

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.

Epidemiological investigation of bovine trypanosomosis and distribution of vectors in Jimma zone, Ethiopia

Trypanosomosis is highly reliant on the distribution of vectors responsible for transmission. A cross-sectional study was conducted to determine the prevalence and associated risk factors of bovine trypanosomosis as well as the distribution of vectors in the Jimma zone, Ethiopia. Blood samples from a total of 2088 cattle were collected and tested using a buffy coat and Giemsa techniques. An overall 13.36% prevalence of trypanosomosis was recorded in study areas. The highest proportion of the infections was caused by T. vivax (44.80%) followed by T. congolense (36.92%) and mixed infection (18.28%) of both species. The study also revealed that trypanosomosis was associated with anemia as the mean PCV was significantly lower among trypanosome-infected animals (20.34 ± 4.39) than non-infected ones (27.98 ± 3.68). Moreover, anemia was more pronounced with T. congolense infection (19.54 ± 3.22) than T. vivax (21.07 ± 3.96) and mixed infection of both species (20.16 ± 2.71). This study identified age, body condition, and agro-ecology as risk factors for the occurrence of trypanosomosis in cattle. Vector survey was conducted by deploying 377 mono-pyramidal traps in selected districts. Accordingly, Glossina species and other biting flies (Stomoxys and Tabanus) were identified with an apparent density of 5.27 and 1.74 fly/trap/day, respectively. Moreover, a higher 4.49 fly/trap/day of G. tachinoides than G. morsitans submorsitans (0.79 fly/trap/day) was noted in study areas. The present study indicated that trypanosomosis is the major cattle production constraint in the areas. Hence, applicable management techniques of the disease and its vector should be implemented and further investigation involving molecular technique should be conducted in different seasons.