Risk factors for the persistence of bovine brucellosis in Sicily from 2008 to 2010

Risk Factors for the Spread of Brucellosis in Sheep and Goats in the Campania Region in the Years 2015-2020

Brucella is a Gram-negative facultative intracellular pathogen that causes infection in sheep and goats (B. melitensis.); B. melitensis can also infect other animals. Sheep and goat brucellosis is still present in some regions of Italy, including Campania, and causes considerable economic losses and health threats. The aim of this study was to evaluate the possible risk factors influencing the spread of brucellosis among sheep and goat farms in the Campania region in order to provide the local veterinary services with practical support in evaluating and planning diagnostic, preventive and control interventions. The results of official controls for brucellosis carried out from 2015 to 2020 in the sheep and goat farms of the Campania Region were analyzed. Data were extracted from the National Veterinary Information Systems and the Laboratory Management System of the Experimental Zooprophylactic Institute of Southern Italy. Statistical analysis was carried out through the software R version 4.1.0; the dataset consisted of 37,442 observations, and 9 qualitative and quantitative variables were evaluated on 8487 farms, 248 of which were positive. The association between covariates and the outcome (presence/absence of the disease) was evaluated (Fisher and Wilcoxon tests). A logistic regression model with mixed effects was carried out. This study confirmed that brucellosis in sheep and goats in the Campania region mostly occurs through contact with infected animals imported from other farms (OR = 3.41-IC 95% [1.82-6.41]). Farms with a greater number of animals were seen to be at the greatest risk of infection (OR = 1.04-IC 95% [1.03-1.05]); previous suspension of healthy status also proved to be a risk factor (OR = 55.8-IC 95% [26.7-117]).

Zoonotic Problems Reported by Sheep and Goat Farmers and Factors Potentially Contributing to the Occurrence of Brucellosis among Them

The study aimed to investigate the occurrence of zoonotic problems reported by dairy small ruminant farmers in Greece and to study potential associations with socio-demographic characteristics of the farmers and management practices applied in the farms. A countrywide investigation was performed in 325 sheep and 119 goat farms in the 13 administrative regions of Greece. The selected farms were visited and interviews were conducted with respective farmers. The occurrence of zoonotic problems in the farmers was recorded. A total biosecurity score (0−6) was devised, based on biosecurity practices followed in farms. Sixty-seven farmers (15.10%, 95% confidence intervals (CI): 12.1−18.7%) reported experiencing a zoonotic problem. Most of the farmers (n = 57) (85.1%, 95% CI: 74.76−91.7%, of those with a zoonotic problem) (12.8%, 95% CI: 10.0−16.3%, of all) reported that the zoonotic problem had been brucellosis. Odds ratio for the occurrence of brucellosis in goat farmers was 1.879 (95% CI: 1.051−3.359) compared to the occurrence of the infection in sheep farmers (p = 0.033). For the outcome ‘occurrence of brucellosis’ in sheep farmers, the application of hand-milking, the availability of a separate lambing area and the presence of cats in the farm emerged as significant (p < 0.01); for the same outcome in goat farmers, only the availability of a separate kidding area emerged as significant (p = 0.001). The mean biosecurity score in farms in the continental area of the country was significantly higher than in the islands: 3.45 ± 0.05 versus 2.76 ± 0.28, respectively (p = 0.006), whilst there was also a significantly higher score in farms, where the farmer reported occurrence of brucellosis: 3.68 ± 0.15 versus 3.34 ± 0.06 in farms, where the farmer did not report such an incident (p = 0.042). In farms, where the above predictors prevail, farmers should be warned of an increased potential risk for human infection and biosecurity measures should be implemented and tightened.

Knowledge and practices of dairy farmers relating to brucellosis in urban, peri-urban and rural areas of Assam and Bihar, India

Background

Brucellosis is one of the most common zoonotic diseases in the world. This study aimed at assessing farmers’ knowledge about brucellosis as well as practices relevant to transmission of brucellosis and their associated determinants.

Results

Few farmers knew about brucellosis (3.4%, n = 18) and its zoonotic importance (0.8%, n = 4). Knowledge about brucellosis was higher for farmers with a larger herd size (p < 0.001) and fully using a stall-fed system (p < 0.001). Training on dairy cattle management (p < 0.001), training on animal disease (p < 0.01), consultation with veterinarians (p < 0.001) and farms being in urban areas (p < 0.01) were also significantly positively associated with knowledge about brucellosis. No significant association was observed between farmers’ knowledge about brucellosis and state, family size, education, age or gender of the farmers. Farmers knowledge about brucellosis was significantly associated with certain practices that include use of disinfectant while cleaning farms (p < 0.05), animal movement (p < 0.01), introduction of new animals (p < 0.05) and raw milk consumption (p < 0.05). The study did not find any association between knowledge about brucellosis and method of disposal of aborted materials, personal hygiene and quarantine practices.

Conclusion

More interaction with veterinarians and training on animal management may be an important tool for generating awareness among the farming community for reducing transmission of the disease.

Use of a generalized additive model for a spatial analysis of bovine brucellosis risk in the state of Mato Grosso in 2002 and 2014

Diseases that affect cattle represent obstacles to the development of livestock activity. Brucellosis is a significant such disease because it is transmissible, has a chronic nature, and causes health and economic damages to the herd and rural producer. Data from surveys performed in 2002 and 2014 were compared to identify the spatial distribution of bovine brucellosis and to evaluate clusters of outbreaks and areas of greater risk to have infected cattle in the state of Mato Grosso, Brazil. The present study analyzed the data obtained in the aforementioned investigations with a statistical model based on a spatial point process called a generalized additive model (GAM). The analysis made it possible to identify the regions of highest and lowest risk in the state of Mato Grosso. Of the 1001 properties analyzed in 2002, 198 were in areas with high-odds ratio, and 121 were in a low-odds ratio area. Of the 1248 properties sampled in 2014, 119 were in a high-odds ratio area, and 162 were in a low-odds ratio area. Areas with high-odds ratio are more likely to have infected cattle and can be considered to be at higher risk for the disease. The results of the present study highlight the reduction in foci, prevalence, and its relationship with the spatial distribution of bovine brucellosis. The study results should help the official defense service of Mato Grosso direct its activities according to the profile of each region.

A multifaceted risk model of brucellosis at the human-animal interface in Egypt

Brucellosis is a highly contagious zoonosis affecting humans and a wide range of domesticated and wild animal species. An important element for effective disease containment is to improve knowledge, attitudes and practices (KAP) of afflicted communities. This study aimed to assess the KAP related to brucellosis at the human-animal interface in an endemic area of Egypt and to identify the risk factors for human infection. A matched case-control study was conducted at the central fever hospitals located in six governorates in northern Egypt. Face-to-face interviews with cases and controls were conducted using a structured questionnaire. In total, 40.7% of the participants owned farm animals in their households. The overall mean practice score regarding animal husbandry, processing and consumption of milk and dairy products were significantly lower among cases compared with controls (-12.7 ± 18.1 vs. 0.68 ± 14.2, respectively; p < .001). Perceived barriers for notification of animal infection/abortion were predominate among cases and positively correlated with participants' education. The predictors of having brucellosis infection were consumption of unpasteurized milk or raw dairy products and practicing animal husbandry. Applying protective measures against infection significantly reduced its risk. A model predicting risk factors for brucellosis among those who own animal showed that frequent abortions per animal increased the chance for brucellosis infection among human cases by 50-fold (95% CI: 8.8-276.9), whereas the use of protective measures in animal care reduced the odds (OR = 0.11 [95% CI: 0.03-0.45]). In conclusion, consumption of unprocessed dairy products was equally important as contact with infected/aborted animals as major risk factors for Brucella spp. infection among humans in Egypt. There is poor knowledge, negative attitudes and risky behaviours among villagers which can perpetuate the risk of brucellosis transmission at the human-animal interface. This supports the need for integrating health education into the national brucellosis control programme.

Knowledge, attitudes and practices (KAPs) and risk factors of brucellosis at the human-animal interface in the Nile Delta, Egypt.. [DOI: 10.1101/607655]

Background

Brucellosis is a highly contagious zoonosis affecting human and almost all domestic species. It is a multi-burdens disease leading to severe economic losses due to disability in humans in addition to abortion, infertility and reduced milk production in animals. An Important element for effective prevention and control of brucellosis is to improve knowledge, attitude and practices of the community.

Objective(s)

This study aimed to assess the knowledge, attitudes and practices (KAP) related to brucellosis at human-animal interface and to determine the risk factors for human infection in the Nile Delta, Egypt.

Methods

A matched case-control study was conducted at the main fever hospitals located in 6 governorates in the Nile Delta, Egypt between June 2014 and June 2016. Face-to-face interviews with cases and controls was done using a structured questionnaire. Differences in proportions of KAP variables among the cases and controls were evaluated by Pearson’s Chi square test and apvalue <0.05 was set as a level of significance. A multivariate conditional logistic regression analysis was built to determine the risk factors for Brucella spp. infection among study participants.

Results

A total of 217 cases and 434 controls matched for age, gender and sociodemographic characteristics were enrolled and interviewed. In total, 40.7% of the participants owned animals in their households and lived in shared accommodation with animals [48.8% of cases vs 36.9% of controls; (p= 0.003)]. The majority (78.1%) used to accommodate cows and buffaloes with sheep and goats. Human brucellosis cases experienced more animal abortions comparing to the controls [(23.5% vs 9.7%, respectively), (p= 0.0003)]. The majority of the participants (82.4%) did not notify authorities in case that abortion occurs in their owned animals. Apparently, 67.4% of the participants [(70.0% of the cases vs 66.1% of the controls) (p= 0.315)] had not ever heard about brucellosis. The overall mean practice score regarding animal husbandry, processing and consumption of milk and dairy products was significantly lower among cases comparing to controls (−12.7±18.1 vs 0.68±14.2 respectively;p<0.0001). Perceived barrier for notification of animal infection and/or abortion was significantly higher among cases (p= 0.034) and positively correlated with participants’ education. Results of univariate analysis showed that participants who have animals’ especially small ruminates were at a higher risk of gettingBrucellaspp. infection than others. In the proposed multivariate conditional logistic regression model, the predictors of having brucellosis infection were consumption of unpasteurized milk, having consumed dairy products in the last 3 months before the study, consumption of yoghurt or home-made cheeses and involvement in contact with animals [OR (95% CI) = 4.12 (1.62 - 10.75); 2.71 (1.06 – 6.93); 2.51 (1.21 – 5.24); 1.96 (1.17- 3.30),p<0.05; and 4.97 (2.84 - 8.72)], respectively. Participants who take more protective measures against infection were at a significant lower risk of being diseased with brucellosis; [OR (95% CI) = 0.23 (0.10 - 0.58);p<0.001], respectively. A model predicting risk factors for brucellosis among those who own animal showed that frequent abortions per animal increased the chance for brucellosis infection among human cases by 49.33 fold [(95% CI)= (8.79 – 276.91);p= 0.001] whereas the practice protective measures with animals was protective for humans as well [OR (95% CI)= 0.11 (0.03-0.45);p= 0.002].

Conclusion

Consumption of dairy products stands side by side with the contact with infected animals particularly aborted ones as the major risk factors forBrucellaspp. infection among humans in Egypt. On the other hand, there is a poor knowledge, negative attitudes and risky behaviors among villagers which increase the magnitude of the risk of brucellosis transmission at the human-animal interface. This supports the need for integrating health education in the national brucellosis control programs in Egypt with a special emphasis on hygienic animal husbandry, disease notification and benefits of animal vaccination.

Author summary

Zoonotic brucellosis has a vast global burden and remains neglected in many areas of the world despite notable advances in disease containment strategies. Despite the implementation of a national brucellosis control program in Egypt, the challenges for the disease eradication are intractable and multifaceted. We modeled in the present study the multivariate factors for brucellosis persistence in Egypt which apparently pointed to lack of basic understanding of the nature of brucellosis, traditional practices, beliefs and risky behaviors being undertaken on farms and at households across a wide region of the country. Predominantly, consumption of dairy products from unregulated sources; underreporting animal infection and abortion; underutilization of animal vaccination service; unsanitary disposal of abortus; use of milk of infected/aborted ruminants and lack of protective measure when practicing animal husbandry. Together, these conflict with disease intervention strategies and contribute to disease spread and re-emergence. The proposed model can provide a framework for future containment strategies that should be adopted to support and enhance the adherence to the current national brucellosis control program.

Characterization and evolution of countries affected by bovine brucellosis (1996-2014)

This paper describes the global distribution and temporal evolution of bovine brucellosis due to Brucella abortus during a 19-year period (1996-2014) using the information officially reported to the World Organisation for Animal Health (OIE) by veterinary services of 156 countries. Variables that can influence the health status of bovine brucellosis (i.e., year, per capita Gross Domestic Product (GDP), continent and bovine population) were also analysed. Countries were classified into three categories of health situations: ENZOOTIC: countries infected, which may have been free of brucellosis but for periods of fewer than 3 years; NON-ENZOOTIC: countries where the disease was present but that had at least a 3-year period without the disease; and FREE: countries where the disease remained absent during the whole period. The countries free from bovine brucellosis, or in the process of eradication, were located in Oceania and Europe, while the more affected regions were Central and South America, Africa and parts of Asia. Among the Non-Enzootic countries, the results showed that a very high proportion managed to control the disease during the period of study, with a sharp decline in the percentage of infected countries from 71% in 1996 to 10% in 2014. Among the Enzootic countries, a much smaller proportion managed to control the disease, with a slight drop in the percentage of infected countries from 92% in 1996 to 80% in 2014. A relationship was found between the status of the disease and the availability of economic resources; thus, countries with a high GDP per capita tended to be free from bovine brucellosis. On the other hand, countries with a larger bovine population showed a greater probability to have the disease present. An increase in surveillance programmes and implementation of control policies were observed during the period of study.

Prevalence and risk factors associated with bovine brucellosis in herds under extensive production system in southwestern Nigeria

Using a cross-sectional survey, we determined the prevalence and risk factors associated with bovine brucellosis in herds under extensive production system in southwestern Nigeria. Antibodies to Brucella species in serum samples were tested using the Rose Bengal test (RBT) and competitive enzyme-linked immunosorbent assay (cELISA); for milk, the milk ring test (MRT) and indirect-ELISA (i-ELISA) were used. Questionnaire was administered to cattle herdsmen to determine factors predisposing the animals to bovine brucellosis. Data were analyzed using STATA 12. From 513 serum and 635 milk samples tested among 120 herds, overall animal-level prevalence of 10.1% (95% CI 7.5-12.7%) and 20.2% (95% CI 17.1-23.3%) were recorded by RBT and MRT, respectively; while 9.4% (95% CI 6.9-11.9%) and 17.8% (95% CI 14.8-20.8%) were obtained using cELISA and i-ELISA, respectively. In all, from the 120 herds tested, 29.2% and 43.3% were positive by RBT and MRT, respectively. Multivariable logistic regression revealed that herd location (OR = 8.12, 95% CI 1.68-38.90) and improper disposal of placenta/fetus (OR = 17.33, 95% CI 4.81-62.33) were predictors for a seropositive herd using RBT; while herd location (OR = 5.13, 95% CI 1.27-20.28), large herd size (OR = 2.62, 95% CI 1.15-5.85), and occurrence of abortion for a year or more (OR = 4.62, 95% CI 1.53-13.71) were predictors of seropositivity to antibodies to Brucella spp. using MRT. We found high prevalence of brucellosis in cattle herds under extensive management system in southwestern Nigeria. Urgent and coordinated control strategies are required to mitigate this problem.

Development of a forecasting model for brucellosis spreading in the Italian cattle trade network aimed to prioritise the field interventions

Brucellosis caused by Brucella abortus is an important zoonosis that constitutes a serious hazard to public health. Prevention of human brucellosis depends on the control of the disease in animals. Livestock movement data represent a valuable source of information to understand the pattern of contacts between holdings, which may determine the inter-herds and intra-herd spread of the disease. The manuscript addresses the use of computational epidemic models rooted in the knowledge of cattle trade network to assess the probabilities of brucellosis spread and to design control strategies. Three different spread network-based models were proposed: the DFC (Disease Flow Centrality) model based only on temporal cattle network structure and unrelated to the epidemiological disease parameters; a deterministic SIR (Susceptible-Infectious-Recovered) model; a stochastic SEIR (Susceptible-Exposed-Infectious-Recovered) model in which epidemiological and demographic within-farm aspects were also modelled. Containment strategies based on farms centrality in the cattle network were tested and discussed. All three models started from the identification of the entire sub-network originated from an infected farm, up to the fifth order of contacts. Their performances were based on data collected in Sicily in the framework of the national eradication plan of brucellosis in 2009. Results show that the proposed methods improves the efficacy and efficiency of the tracing activities in comparison to the procedure currently adopted by the veterinary services in the brucellosis control, in Italy. An overall assessment shows that the SIR model is the most suitable for the practical needs of the veterinary services, being the one with the highest sensitivity and the shortest computation time.

Origins and global context of Brucella abortus in Italy

Background

Brucellosis is a common and chronic disease of cattle and other bovids that often causes reproductive disorders. Natural infection in cattle is caused by Brucella abortus and transmission typically occurs during abortions, calving, or nursing. Brucellosis is also a major zoonotic disease due to contamination of dairy products or contact with the tissues of infected animals. Brucellosis has been eradicated from most of the developed world in the last 40 years but persists in many regions—the disease remains prevalent in portions of Africa, the Middle East, Asia, and Central and South America, as well as in the Mediterranean basin. In Italy, B. abortus has persisted in southern regions in both cattle and water buffalo. Previous attempts at analyzing the phylogenetics of B. abortus in Italy have been challenging due to limited genetic variability and unresolved global population genetic structure of this pathogen.

Results

We conducted genome-wide phylogenetic analyses on 11 representative strains of B. abortus from Italy, and compared these sequences to a worldwide collection of publically available genomes. Italian isolates belong to three clades that are basal to the main and global B. abortus lineage. Using six SNP-based assays designed to identify substructure within the Italian clades, we surveyed a collection of 261 isolates and found that one clade predominates throughout endemic districts in the country, while the other two clades are more geographically restricted to portions of southern Italy.

Conclusions

Although related strains exist worldwide, B. abortus isolates from Italy are substantially different than those found in much of the rest of Europe and North America, and are more closely related to strains from the Middle East and Asia. Our assays targeting genetic substructure within Italy allowed us to identify the major lineages quickly and inexpensively, without having to generate whole genome sequences for a large isolate collection. These findings highlight the importance of genetic studies to assess the status and the history of pathogens.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-017-0939-0) contains supplementary material, which is available to authorized users.

Sources of spatial animal and human health data: Casting the net wide to deal more effectively with increasingly complex disease problems

During the last 30years it has become commonplace for epidemiological studies to collect locational attributes of disease data. Although this advancement was driven largely by the introduction of handheld global positioning systems (GPS), and more recently, smartphones and tablets with built-in GPS, the collection of georeferenced disease data has moved beyond the use of handheld GPS devices and there now exist numerous sources of crowdsourced georeferenced disease data such as that available from georeferencing of Google search queries or Twitter messages. In addition, cartography has moved beyond the realm of professionals to crowdsourced mapping projects that play a crucial role in disease control and surveillance of outbreaks such as the 2014 West Africa Ebola epidemic. This paper provides a comprehensive review of a range of innovative sources of spatial animal and human health data including data warehouses, mHealth, Google Earth, volunteered geographic information and mining of internet-based big data sources such as Google and Twitter. We discuss the advantages, limitations and applications of each, and highlight studies where they have been used effectively.

Epidemiology of brucellosis among cattle in Korea from 2001 to 2011

In the present study, the outbreak patterns of bovine brucellosis in Korea from 2000 to 2011 were analyzed to understand the epidemiological evolution of this disease in the country. A total of 85,521 brucella reactor animals were identified during 14,215 outbreaks over the 12-year study period. The number of bovine brucellosis cases increased after 2003 and peaked in 2006 before decreasing thereafter. The majority of the bovine brucellosis cases were Korean native cattle, Han Woo. The numbers of human brucellosis cases and cattle outbreaks increased and decreased in the same pattern. The correlation coefficient for human and bovine cases per year was 0.96 (95% confidence interval = 0.86~0.99; p < 10^-3). The epidemiological characteristics of bovine brucellosis appeared to be affected by the intensity of eradication programs that mainly involved a test-and-slaughter policy. Findings from the present study were based on freely available statistics from web pages maintained by government agencies. This unlimited access to information demonstrates the usefulness of government statistics for continually monitoring the health of animal populations.