Herd-level risk factors for Campylobacter fetus infection, Brucella seropositivity and within-herd seroprevalence of brucellosis in cattle in northern Nigeria

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 analyzed 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 < 0.05) 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<0.05) than in other regions. Reports conducted using ELISA and serial Rose Bengal plate test (RBPT)-ELISA had higher (p<0.05) 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. This article is protected by copyright. All rights reserved.

Prevalence and Antibiotic Resistance in Campylobacter spp. Isolated from Humans and Food-Producing Animals in West Africa: A Systematic Review and Meta-Analysis

Campylobacter species are one of the leading causes of gastroenteritis in humans. This review reports on the prevalence and antibiotic resistance data of Campylobacter spp. isolated from humans and food-producing animals in West Africa. A systematic search was carried out in five databases for original articles published between January 2000 and July 2021. Among 791 studies found, 38 original articles from seven (41%) out of the 17 countries in West Africa met the inclusion criteria. For studies conducted in food-producing animals, the overall pooled prevalence of Campylobacter spp. was 34% (95% CI: 25–45). The MDR prevalence was 59% (95% CI: 29–84) and half (50%, 13/26) of the animal studies had samples collected from the market. The human studies recorded a lower pooled prevalence of Campylobacter spp. (10%, 95% CI: 6–17), but a considerably higher rate of MDR prevalence (91%; 95% CI: 67–98). The majority (85%, 11/13) of the human studies took place in a hospital. Campylobacter jejuni and Campylobacter coli were the most common species isolated from both animals and humans. Our findings suggest that Campylobacter spp. is highly prevalent in West Africa. Therefore, improved farm hygiene and ‘One Health’ surveillance systems are needed to reduce transmission.

Prevalence, distribution and risk factors for brucellosis infection in goat farms in Ningxiang, China

Background

In south China, goats are the major source of Brucellosis for human infection. However, there are few studies on the prevalence of and risk factors for goat brucellosis in south China. In this study, we conducted a cross-sectional study to investigate the herd prevalence, spatial distribution and relevant risk factors for goat brucellosis in Ningxiang county, south China. Commercial goat farms (n = 457) were randomly selected, and their disease status was ascertained by testing serum samples of chosen individuals using the Rose Bengal Test (screening test) and the Serum Agglutination Test (confirmatory test) in series. A farm with at least two positive individuals was defined as a case farm. Standardized questionnaires were used to collect information on management and hygiene practices in farms. A logistic model with a binomial outcome was built to identify risk factors for being seropositive.

Results

The true herd prevalence in commercial goat farms was 4.5% (95%CI: 0.2%-12.2%) and the townships in the centre of the county had higher herd prevalence. The risk factors associated with seropositive on local goat farms include “Introduction in the past 12 months” (OR= 61, 95%CI: 16-333), “Improperly disposal of the sick or dead goats” (OR= 33, 95%CI: 5-341) and “Poor hygiene in lambing pen” (OR= 25, 95%CI: 5-192).

Conclusions

These findings will aid in the development of control strategies of Brucellosis in south China and risk factors identified in this study should be taken into consideration when designing a control strategy.

Evaluation of a milk ELISA as an alternative to a serum ELISA in the determination of the prevalence and incidence of brucellosis in dairy herds in Hubei Province, China

This study was designed to compare a milk I-ELISA with a serum ELISA for the diagnosis of brucellosis in dairy cattle and then to use the milk I-ELISA to determine the prevalence and incidence of brucellosis in dairy herds in Hubei Province, China. The two tests were shown to have good agreement with a Cohen's kappa statistic of 0.747 (p < 0.001) when 147 animals originating from 4 dairy herds in the province were tested. The results of Bayesian Latent Class Analysis estimated that the sensitivity and specificity of the milk I-ELISA under field conditions were 87.2 % and 92.0 %, respectively. An epidemiological survey based on the milk I-ELISA was then conducted in 3091 cows from 15 commercial dairy herds from January to July 2018 in Hubei Province. The animal level real prevalence varied from 34.9 % (95 % CI: 28.5, 41.8) to 51.4 % (95 % CI: 48.2, 54.6) in the 15 herds tested. Most farms (93.3 %) tested contained at least one test-positive animal. As only ten farms met the inclusion criteria for the calculation of incidence risk, the overall real incidence risk in 10 of these farms was 0.4 % (95 % CI: 0.1, 1.2) per 3 months, which highlights the potential for spread of the disease within infected herds. It is concluded that the milk I-ELISA test could be used as a rapid screening test for brucellosis in unvaccinated dairy cows and, given the high occurrence of bovine brucellosis in this study, an effective prevention and control program needs to be developed and implemented in Hubei Province, China.

The spatiotemporal distribution of human brucellosis in mainland China from 2007-2016

Background

Despite the considerable efforts made to address the issue of brucellosis worldwide, its prevalence in dairy products continues to be difficult to estimate and represents a key public health issue around the world today. The aim of the present study was to better understand the epidemiology of this disease in mainland China. We set out to investigate the yearly spatial distribution and possible hotspots of the disease.

Methods

Human brucellosis data from mainland China between 2007 and 2016 were collected from the China Information System for Disease Control and Prevention. A geographic information system ArcGIS10.3 (ESRI, Redlands) was used to identify potential changes in the spatial and temporal distribution of human brucellosis in mainland China during the study period. These distributions were evaluated using three-dimensional trend analysis and spatial autocorrelation analyse. A gravity-center was used to analyse the migration track of human brucellosis.

Results

A total of 399,578 cases of human brucellosis were reported during the 10-year study period. The monthly incidence of brucellosis in China demonstrates clear seasonality. Spring and summer are the peak seasons, while May is the peak month for brucellosis. Three-dimensional trend analysis suggests that brucellosis is on the rise from south to north, and that the epidemic situation in northern China is more severe. Between 2007 and 2016, the overall migration distance of the brucellosis incidence gravity-center was 906.43 km, and the direction was southwest. However, the overall gravity center of brucellosis was still in the northern part of China. In the global autocorrelation analysis, brucellosis in China demonstrated a non-random distribution between 2013 and 2014, with spatial autocorrelation (Z > 1.96, P < 0.05) and a clustering trend, while no clustering trend was found from 2007 to 2012 or from 2015 to 2016. In the local autocorrelation analysis, a Low-Low cluster phenomenon was found in the south of China in 2013 and 2014.

Conclusion

Human brucellosis remains a widespread challenge, particularly in northern China. The hotspots highlight potential high-risk areas which may require special plans and resources for monitoring and controlling the disease.

Epidemiology and antimicrobial resistance of Campylobacter spp. in animals in Sub-Saharan Africa: A systematic review

Introduction

Low sanitary conditions characterize the rural and urban households in Sub-Saharan African region. Those environmental conditions propitiate the transmission of bacterial infections between animals and humans. Campylobacter spp. is a zoonotic bacterium and cause of human gastroenteritis worldwide, whose main symptom is diarrhea. It is normally found in the digestive tract of many farm animals as a commensal but some species cause diseases in animals. It is important to understand the occurrence of these bacteria in animals, as they may also play a role in transmission to humans. The main objective of this review was to describe the prevalence of Campylobacter in animals in Sub-Saharan Africa. We also report findings on antibiotic resistance.

Methods

We followed PRISMA guidelines to find studies about occurrence of Campylobacter spp. in animals in all countries from Sub-Saharan Africa. PubMed, Cochrane Library, CINAHL, African Index Medicus, African Journals Online, Google Scholar and Science Direct were searched for studies published between 2000 and 2019.

Results

We found 70 studies that described occurrence of Campylobacter spp. in animals in 18 out of 53 countries of Sub-Saharan Africa. Campylobacter jejuni and C. coli were the predominant species isolated. The majority of studies were found in Western Africa. Middle Africa had the lowest amount of data. Most records presented data from Nigeria (n = 25), South Africa (n = 14) and Tanzania (n = 11). Cattle and chickens appear to be important hosts and may be playing an important role in transmitting to humans. Most Campylobacter isolates were resistant to erythromycin (44%), ampicillin (39%), tetracycline (33%), nalidixic acid (31%) and ciprofloxacin (30%).

Conclusion

Several studies about Campylobacter spp. in animals have been published in the last 19 years but information on the epidemiology of campylobacteriosis is scarce in most Sub-Saharan African countries. Antibiotic resistance is an increasing concern in many countries. Measures should be taken to prevent infection by this pathogen in the region and to control antibiotic resistance.

A retrospective epidemiological analysis of shared risk factors for bovine trichomoniasis and bovine genital campylobacteriosis in La Pampa province (Argentina)

The venereal diseases bovine trichomoniasis (BT) and bovine genital campylobacteriosis (BGC) cause economic losses in endemic areas like La Pampa province in Argentina, where beef cattle are usually managed extensively. The eradication of both diseases is a priority in Argentine. The aim of this case-control study was to identify shared and specific risk factors of both diseases from the data obtained from the Provincial Program for the Control and Eradication of BT and BGC in La Pampa (PCE). The study population included 5777 breeding beef herds tested for BT and BGC in 2013. The study comprised 3481 herds that were surveyed in situ by official PCE veterinarians, distributed as follows: 3159 negative herds (with no BT or BGC positive bulls), 121 BT case herds (with at least a BT positive bull), 170 BGC case herds (with at least a BGC positive bull) and 31 BT and BGC co-infected case herds (with at least a positive bull for each disease). Three multivariable analyses were performed in order to identify the risk factors using a logistic regression model. Results showed that the risk factors shared by both diseases were the number of bulls (OR for BT = 1.03, 95% CI: 1.02-1.04, p <  0.001; OR for BGC = 1.02, 95% CI: 1.01-1.03, p <  0.001; OR for BT and BGC co-infection = 1.02, 95% CI: 1.01-1.04, p =  0.003) and the presence in the previous year of each disease (OR for BT = 18.69, 95% CI: 11.82-29.57, p <  0.001; OR for BGC = 4.65, 95% CI: 3.18-6.81, p <  0.001; OR for BT and BGC co-infection = 39.18, 95% CI: 16.72-91.80, p <  0.001). Disease-specific risk factors were continuous breeding season for BT (OR = 1.59, 95% CI: 1.04-2.47, p =  0.034), and inadequate condition of the fences for BGC (OR = 1.51, 95% CI: 1.06-2.15, p =  0.022). An integrated approach to venereal disease management needs to consider the risk characteristics identified in this study. This could lead to reduce both diseases and improve the efficiency of BT and BGC control activities in La Pampa.

Ocorrência da infecção por Campylobacter fetus subsp. venerealis e Tritrichomonas foetus em búfalos no estado de Pernambuco, Brasil

RESUMO Objetivou-se com estudo determinar a ocorrência da infecção por Campylobacter fetus subsp. venerealis e Tritrichomonas foetus em búfalos no estado de Pernambuco, Brasil. Foram coletadas 133 amostras biológicas (muco cervicovaginal e raspado prepucial) de animais, procedentes de oito propriedades, de diferentes regiões do estado. O material biológico coletado foi transferido para solução salina tamponada (PBS) e, posteriormente, inoculado em meios de transporte específicos, Lander para diagnóstico de C. fetus subsp. venerealis e Diamond para T. foetus. Para o diagnóstico das infecções por Campylobacter fetus subsp. venerealis e Tritrichomonas foetus, as amostras foram submetidas à reação em cadeia da polimerase (PCR) e cultivadas em meio ágar Columbia acrescido de antibiótico e Diamond, respectivamente. Para pesquisa de C. fetus subsp. venerealis, observou-se uma ocorrência de 1,8% (2/113) de animais positivos no exame microbiológico com confirmação pela PCR. Em relação à procedência, observou-se que 100% das amostras positivas pertenciam a dois machos do mesmo rebanho. Nenhum animal foi positivo na pesquisa de T. foetus. Este é o primeiro registro da infecção por C. fetus subsp. venerealis em búfalos no Brasil. Apesar da baixa ocorrência, recomenda-se adoção de medidas de controle, com o intuito de se evitar a disseminação do agente para outros rebanhos.

Dairy farm demographics and management factors that played a role in the re-emergence of brucellosis on dairy cattle farms in Fiji

Little is published on risk factors associated with bovine brucellosis in Pacific island communities. The 2009 re-emergence of bovine brucellosis in Fiji enabled us to do an interview-based questionnaire survey of 81 farms in the Wainivesi locality of the Tailevu province on the main island of Fiji to investigate what risk factors could have played a role in the re-emergence of the disease. The survey was conducted on 68 farms that had no positive cases of bovine brucellosis and on 13 farms in the same area where cattle had returned a positive result to the Brucella Rose Bengal test. Descriptive statistical methods were used to describe the demographic data while univariate analysis and multivariate logistic regression were used to evaluate the association between the selected risk factors and the presence of brucellosis on the farms at the time of the outbreak. The demographics of Fijian dairy farms are presented in the article and the biosecurity implications of those farming systems are discussed. Two risk factors were strongly associated with farms having brucellosis, and these were history of reactor cattle to brucellosis and or bovine tuberculosis on the farm (OR = 29, P ≤ 0.01) and farms that practised sharing of water sources for cattle within and with outside farms (OR = 39, P ≤ 0.01). Possible reasons why these were risk factors are also discussed. The potential risks for human health was also high as the use of personal protective equipment was low (15%). A high proportion of farmers (62%) could not recognise brucellosis thus contributing to the low frequency of disease reports (44%) made. The article also highlights other important risk factors which could be attributed to farming practices in the region and which could contribute to public health risks and the re-emergence of diseases.

First isolation, identification, phenotypic and genotypic characterization of Brucella abortus biovar 3 from dairy cattle in Tanzania

BACKGROUND

Brucellosis is a disease of worldwide public health and economic importance. Successful control is based on knowledge of epidemiology and strains present in an area. In developing countries, most investigations are based on serological assays. This study aimed at investigating a dairy herd experiencing abortions in order to establish within-herd seroprevalence to Brucella spp., identify, characterize Brucella strains by Multiple Loci Variable Number of Tandem Repeats Analysis (MLVA-VNTR) and investigate possible spillover to other species.

RESULTS

The within-herd seroprevalence in cattle (n = 200) was 48 % (95 % CI 41-55), using an indirect ELISA, while the Rose Bengal Test (RBT) yielded lower prevalence (21.5 %; 95 % CI 16-27). Two sheep (n = 35) and one goat (n = 50) were seropositive using ELISA while none of the dogs (n = 6) was positive with the RBT. Three Brucella were isolated from an aborted fetus and associated membranes. Real time PCR (IS711), Bruce-ladder and classical biotyping classified the isolates as B. abortus biovar 3. MLVA-VNTR revealed two different but closely related genotypes. The isolates showed unique profiles, providing the first genotypic data from Tanzania. These genotypes were not related to B. abortus biovar 3 reference strain Tulya originally isolated from a human patient in Uganda in 1958, unlike the genotypes isolated and characterized recently in Kenya. High within-herd prevalence, isolation of the pathogen and abortion confirm that B. abortus is circulating in this herd with cattle as reservoir hosts. A low seroprevalence in sheep and goats suggests a spillover of B. abortus from cattle to small ruminants in the herd.

CONCLUSIONS

This is the first isolation and characterization of B. abortus biovar 3 from a dairy cow with abortion in Tanzania. The origin of the Tanzanian genotypes remain elusive, although they seem to be related to genotypes found in Europe, Turkey and China but not related to B. abortus biovar 3 reference strain or genotypes from Kenya. Importantly, replacement heifers are commonly sourced from large farms like this to smallholder farmers, which poses risk of spread of bacteria to other herds. B. abortus is a significant zoonotic risk and animal health problem in this production system, therefore further studies on humans is recommended.

Prevalence and risk factors associated with bovine genital campylobacteriosis and bovine trichomonosis in the state of Pernambuco, Brazil

The aim of the present study was to determine the prevalence and risk factors associated with Campylobacter fetus subsp. venerealis and Tritrichomonas foetus infection in cows from dairy herds in the state of Pernambuco, Brazil. In total, 383 samples of cervico-vaginal mucus were collected from cows on 21 herds in 19 districts. Genomic DNA was extracted from the samples and submitted for polymerase chain reaction analysis. An investigative questionnaire was used to analyze the risk factors, using questions related to reproductive and hygiene/sanitation management. A prevalence of 1.8% (0.8-3.9%; confidence interval (CI) 95%) and 33.4% (28.7-38.4%; CI 95%) was found for C. fetus subsp. venerealis and T. foetus, respectively. In terms of the number of foci, 28.6% of the herds contained at least one animal that was positive for C. fetus subsp. venerealis and 90.5% for T. foetus. The present study identified herds larger than 100 animals as a risk factor for bovine genital campylobacteriosis (OR = 7.2; CI 1.3-38.4%; p = 0.020) and the use of natural breeding as a risk factor for bovine trichomonosis (OR = 2.4; CI 1.1-5.9%; p = 0.041). In conclusion, C. fetus subsp. venerealis and T. foetus infections occurred in the region studied and high numbers of foci were found. Thus, prophylaxis and control measures, such as diagnosis, separation, and sexual rest for infected females, are suggested. An artificial insemination program with early rigorous sanitary care should be implemented on the properties in order to avoid the spread of agents in the herds.

Brucellosis, genital campylobacteriosis and other factors affecting calving rate of cattle in three states of Northern Nigeria

Background

Reproductive diseases limit the productivity of cattle worldwide and represent an important obstacle to profitable cattle enterprise. In this study, herd brucellosis and bovine genital campylobacteriosis (BGC) status, and demographic and management variables were determined and related to predicted calving rate (PrCR) of cattle herds in Adamawa, Kaduna and Kano states, Nigeria. Serum samples, preputial scrapings, questionnaire data, trans-rectal palpation and farm records were used from 271 herds. The Rose-Bengal plate test and competitive enzyme-linked immunosorbent assay were used for Brucella serology and culture and identification from preputial samples for BGC. A herd was classified as positive if one or more animals tested positive. The PrCR was determined as the number of calvings expected during the previous 6 and next 6 months as a percentage of the number of postpubertal heifers and cows in the herd. A multilevel linear regression model was used to estimate the herd-level effect of Brucella abortus seropositivity, Campylobacter fetus infection and other factors on calculated PrCR.

Results

The reproductive performance of the cattle herds was generally poor: Only 6.5% of the nursing cows were pregnant and 51.1% were non-pregnant and acyclic; the mean annual PrCR was 51.4%. Brucella abortus and C. fetus infection of herds were independently associated with absolute reduction in PrCR of 14.9% and 8.4%, respectively. There was also a strong negative association between within-herd Brucella seroprevalence and PrCR. Presence of small ruminants, animal introduction without quarantine and the presence of handling facilities were associated with lower PrCR, whereas larger herd size, supplementary feeding, routine mineral supplementation and care during parturition were associated with higher PrCR.

Conclusions

Brucellosis and BGC may be largely responsible for the poor reproductive performance of indigenous Nigerian cattle. Farmer education and measures to improve the fertility of cattle herds are suggested.

A case-control study of risk factors for bovine brucellosis seropositivity in Peninsular Malaysia

Bovine brucellosis was first reported in Peninsular Malaysia in 1950. A subsequent survey conducted in the country revealed that the disease was widespread. Current knowledge on the potential risk factors for brucellosis occurrence on cattle farms in Malaysia is lacking. Therefore, we conducted a case-control study to identify the potential herd-level risk factors for bovine brucellosis occurrence in four states in the country, namely Kelantan, Pahang, Selangor and Negeri Sembilan. Thirty-five cases and 36 controls of herds were selected where data on farm management, biosecurity, medical history and public health were collected. Multivariable logistic regression identified that Brucella seropositive herds were more likely to; have some interaction with wildlife (OR 8.9, 95% CI = 1.59–50.05); originated from farms where multiple species such as buffalo/others (OR 41.8, 95% CI = 3.94–443.19) and goat/sheep (OR 8.9, 95%Cl = 1.10–71.83) were reared, practice extensive production system (OR 13.6, 95% CI 1.31–140.24) and have had episodes of abortion in the past (OR 51.8, 95% CI = 4.54–590.90) when compared to seronegative herds. Considering the lack of information on the epidemiology of bovine brucellosis in peninsular Malaysia and absence of information on preventing the inception or spread of the disease, this report could contribute to the on-going area-wise national brucellosis eradication program.