Multiple Livestock Species Research Articles

Efficient markerless genetic manipulation of Pasteurella multocida using lacZ and pheSm as selection markers.

Pasteurella multocida is a zoonotic conditional pathogen that infects multiple livestock species, causing substantial economic losses in the animal husbandry industry. An efficient markerless method for gene manipulation may facilitate the investigations of P. multocida gene function and pathogenesis of P. multocida. Herein, a temperature-sensitive shuttle vector was constructed using lacZ as a selection marker, and markerless glgB, opa, and hyaE mutants of P. multocida were subsequently constructed through blue-white colony screening. The screening efficiency of markerless deletion strains was improved by the lacZ system, and the method could be used for multiple gene deletions. However, the fur mutant was unavailable via this method. Therefore, we constructed a pheSm screening system based on mutated phenylalanine tRNA synthetase as a counterselection marker to achieve fur deletion mutant. The transformed strain was sensitive to 20 mM p-chloro-phenylalanine, demonstrating the feasibility of pheSm as a counter-selective marker. The pheSm system was used for markerless deletions of glgB, opa, and hyaE as well as fur that could not be screened by the lacZ system. A comparison of screening efficiencies of the system showed that the pheSm counterselection system was more efficient than the lacZ system and broadly applicable for mutant screening. The methods developed herein may provide valuable tools for genetic manipulation of P. multocida.IMPORTANCEPasteurella multocida is a highly contagious zoonotic pathogen. An understanding of its underlying pathogenic mechanisms is of considerable importance and requires efficient species-specific genetic tools. Herein, we propose a screening system for P. multocida mutants using lacZ or pheSm screening markers. We evaluated the efficiencies of both systems, which were used to achieve markerless deletion of multiple genes. The results of this study support the use of lacZ or pheSm as counterselection markers to improve counterselection efficiency in P. multocida. This study provides an effective genetic tool for investigations of the virulence gene functions and pathogenic mechanisms of P. multocida.

Identification and validation of stable reference genes for expression profiling of target genes in diverse ovine tissues

Quantitative PCR (qPCR) is a widely-used technique for quantifying the expression of target genes across various tissues, as well as under different pathological and physiological conditions. One of the challenges associated with this method is the need to identify optimal reference genes (RGs) that maintain consistent expression levels under diverse experimental settings, thereby ensuring accurate biological interpretation. In this study, we conducted a thorough analysis of 18 candidate RGs (ACTB, BACH1, B2M, GAPDH, HMBS, HPRT1, PGK1, PPIA, PPIB, RPLP0, RPL19, RPS9, RPS15, RPS28, SDHA, TBP, UXT, and YWHAZ) across 10 ovine tissues (muscle, skin, kidney, liver, intestine, rumen, lung, testis, heart, and spleen) obtained from five individual sheep. We aimed to identify genes with stable expression across these tissues. A literature-based survey helped us shortlist candidate genes representing various functional classes from multiple livestock species. We employed four algorithms: geNorm, NormFinder, BestKeeper, and Delta Ct (ΔCt), to rank these genes based on their stability. A consistent trend in the rankings was observed across these different algorithms. RefFinder was then used for a comprehensive ranking, integrating the outputs from the various methods. ACTB, PPIB, BACH1, and B2M emerged as the most stable RGs, while RPS9, RPS15, and PGK1 displayed variable expression. We validated our findings through qPCR analysis of four target genes (ACTN2, CRYAB, DLK1, and TRIM54) in the skin samples from two different sheep breeds. Based on these results, we recommend ACTB, PPIB, BACH1, and B2M as reliable internal control genes for qPCR experiments involving diverse ovine tissues.

Grassland degradation induces high dietary niche overlap between two common livestock: cattle and sheep

AbstractIntroductionDiet selection of grazing livestock is one of the critical factors affecting the diversity and composition of plant communities in grasslands, with consequent impacts for ecosystem functioning. Co‐grazing of multiple livestock species could create additive or complementary effects on plant communities due to diet overlap or differentiation among livestock species. However, there is only limited knowledge about diet overlap and differentiation of co‐occurring livestock species and whether or how these diet characteristics change with grassland degradation.Materials and MethodsWe experimentally test the diets of two commonly co‐occurring livestock species (cattle and sheep) and the dietary niche partitioning/overlap between them in non‐degraded, moderately and severely degraded grasslands.ResultsCattle exhibited broader diet than sheep, and diet overlap between species was lower in non‐degraded grasslands. As grassland degradation increased the availability of annual plants, interspecific niche overlap between cattle and sheep gradually increased, and cattle suffered a resulting dietary niche compression. Sheep maintained a relatively narrow and constant dietary breadth.ConclusionThe increasing dietary niche overlap between livestock species with increasing extent of grassland degradation indicated increased additive effects of cattle and sheep co‐grazing on plant community, and thus stronger effects on plant community composition and diversity.

Multiple-year farm-level assessments of trade-offs between GHG emissions and income: case examples of two farming systems in Northern Nigeria.

This study quantifies the trade-offs between welfare (measured by income) and greenhouse gas (GHG) emissions in two farming systems of Northern Nigeria using data for 5 years from 2015 to 2019. The analyses employ a farm-level optimization model that maximizes the value of production less purchased input costs for agricultural activities including the production of trees, sorghum, groundnut or soybeans, and multiple livestock species. We compare income and GHG emissions without constraints to scenarios requiring reductions in emissions of either 10% or the maximum reduction feasible while maintaining minimum household consumption levels. For both locations and all years, we find that reductions in GHG emissions would lower household incomes and require substantive modifications to production patterns and input use. However, the extents to which reductions are possible and the patterns of income-GHG trade-offs vary, indicating that such effects are site-specific and time-variable. The variable nature of these trade-offs suggests challenges for the design of any program that would seek to compensate farmers for reductions in their GHG emissions.

Utilisation of Non-Conventional Animal Waste as Feeds by Multiple Livestock Species Farmers in Lake Victoria Crescent of Central Uganda

Utilisation of Non-Conventional Animal Waste as Feeds by Multiple Livestock Species Farmers in Lake Victoria Crescent of Central Uganda

Risk factors of Shiga toxin-producing Escherichia coli in livestock raised on diversified small-scale farms in California.

The increasing number of diversified small-scale farms (DSSF) that raise outdoor-based livestock in the USA reflects growing consumer demand for sustainably produced food. Diversified farms are small scale and raise a combination of multiple livestock species and numerous produce varieties. This 2015-2016 cross-sectional study aimed to describe the unique characteristics of DSSF in California, estimate the prevalence of Shiga toxin-producing Escherichia coli (STEC) in livestock and evaluate the association between risk factors and the presence of STEC in livestock, using generalised linear mixed models. STEC prevalence was 13.62% (76/558). Significant variables in the mixed-effect logistic regression model included daily maximum temperature (OR 0.95; CI95% 0.91-0.98), livestock sample source (cattle (OR 4.61; CI95% 1.64-12.96) and sheep (OR 5.29; CI95% 1.80-15.51)), multiple species sharing the same barn (OR 6.23; CI95% 1.84-21.15) and livestock having contact with wild areas (OR 3.63; CI95% 1.37-9.62). Identification of STEC serogroups of public health concern (e.g. O157:H7, O26, O103) in this study indicated the need for mitigation strategies to ensure food safety by evaluating risk factors and management practices that contribute to the spread and prevalence of foodborne pathogens in a pre-harvest environment on DSSF.

Gender relations in livestock production and animal-source food acquisition and consumption among smallholders in rural Timor-Leste: A mixed-methods exploration

Among smallholders, gender relations shape how agricultural products are produced and how foods are acquired and consumed, which impacts food security and nutrition. In Timor-Leste, most rural households own multiple livestock species, yet intake of animal-source foods (ASF) is low and malnutrition high. This study explores how gender relations inform livestock production and ASF acquisition and consumption in four Timorese villages in Baucau and Viqueque districts. We examined women's empowerment within the relational sphere of gender relations and applied a qualitative-dominant mixed-methods design. We used ownership and decision-making data from the Abbreviated Women's Empowerment in Agriculture Index (n = 161 women, n = 106 men) and 24-hr ASF recalls (n = 161 mother-child pairs). Findings were complemented with those from 33 semi-structured interviews, mostly with women and/or their husbands, analyzed through the Gender Relations Framework. We found that most women and men reported joint livestock ownership and joint decision-making on production and income. However, interviews revealed that for many women, joint decisions meant requiring their husband's consent, without which they would not proceed with selling livestock or purchasing ASF. Women's unequal bargaining position was influenced by social norms on the gendered division of labor, and by men's role and framing as income generators. In a setting where rice security was a priority concern, ASF were considered non-essential and unaffordable. Mixed-methods are valuable to understand the contextual significance of decision-making processes, as only through qualitative methods did the limited agency of women to exercise their voice in shaping final decisions become apparent. In their design, nutrition-sensitive programmes could include men as important actors in financial decisions that might affect dietary composition.

What drives small-scale farmers to vaccinate their multiple livestock species animals against common infectious diseases in Myanmar?

Livestock rearing is an important income source for small-scale farmers in Myanmar, but Foot and Mouth Disease (FMD) and Newcastle disease (ND) are major constraints to livestock production. A study was conducted to identify perceptions of farmers about FMD and ND disease risks and perceptions about vaccination practices by using the modified health belief model. The majority of livestock farmers (>70%) reported that they were aware of the risk and impact of FMD and ND and were willing to vaccinate their livestock (>60%). Focusing on three main livestock farmer groups, about 17.0% of cattle, 15.4% of village chicken, but only 2.3% of small ruminant owners, indicated that the non-availability of vaccinations in the villages was the major constraint to vaccinations (p<0.001), while in contrast twice as many small ruminant farmers compared to cattle and village chicken farmers indicated they had no knowledge about vaccinations and no funds to conduct vaccinations. Limited accessibility to vaccines and vaccinators was related to size of villages (p = 0.001 for cattle; p = 0.027 for small ruminants; p = 0.005 for village chicken). Willingness to vaccinate small ruminants against FMD was associated with the perceived impact of the disease on sales and accessibility of information about vaccination. Accessibility to information about ND vaccination influenced the willingness of village chicken farmers to conduct vaccinations. In addition, beliefs in the effectiveness of vaccinations played a major role in the willingness to carry out vaccinations on both, cattle (β = 0.3, p = 0.018) and village chicken farms (β = 0.5, p<0.001). Our study highlights that policies that increase the accessibility of vaccines and the dissemination of information about disease prevention and vaccination practices in villages of all sizes, have the potential to increase FMD and ND vaccination rates and thereby reduce outbreak occurrence in Myanmar. On the other hand, indirect factors, such as village size strongly influenced the availability of vaccinations.

A scientific basis for promoting grassland ecosystemmultifunctionality by diversifying grazing livestock: A review

The grassland is the largest terrestrial ecosystem in the world. How to manage and maintain grassland ecosystem functionality is becoming a critical issue as grasslands face serious degradation under the increasing pressures of global change. Livestock grazing is one such pressure, and it is the most widespread land use on Earth. Here, we explore theories and empirical evidence regarding how diversifying grazing livestock species and breeds could potentially improve grassland ecosystem multifunctionality. First, livestock grazing has been known to affect grassland multitrophic biodiversity, and thereby ecosystem multifunctionality. Different livestock species, such as cattle and sheep, vary in their foraging mode, diet, trampling effect and movement as well as in the quantity, distribution, and chemical composition of their excreta deposited in grasslands. As a result, diversity in livestock grazers leads to a variety of disturbances, higher landscape heterogeneity and more varied niches for plants, insects and soil organisms to inhabit. Therefore, diversity in grazers promotes higher overall ecosystem biodiversity. Second, livestock is an important dispersal agent for plants because they reduce intraspecific competition, minimize loss of genetic diversity and mitigate inbreeding. This leads to a more viable and diverse plant population. Third, diverse livestock species in natural grassland ecosystems may ecologically replace large-bodied and extinct native herbivores, and they certainly directly increase herbivore diversity, in grassland ecosystems. Finally, when a variety of livestock species or breeds grazes in the same grassland, it can lead to complex multi-species interactions. These interactions can be attributed to different nutritional demands and selections, and they thus greatly enhance trophic complexity and ecosystem functioning. At its core, the theory of diversifying livestock grazing aims to choose herbivores with different morphological, physiological or behavioral characteristics to thereby exert diverse disturbance on grasslands, rather than a single stressor. These diversified groups of livestock could comprise animal species of different functional groups, such as grazers and browsers, different species of the same functional group, or even different breeds of the same species. The greater the morphological, physiological and behavioral differences among livestock, the more sustainable is the grazing. Further, this diversity can also be created by adjusting the relative abundance of each species or variety, or by adopting one of two grazing modes; where all livestock graze in the same grassland at the same time (i.e., mixed grazing), or at different times (i.e., alternate grazing). In conclusion, altering livestock species composition and grazing intensity may improve grassland ecosystem functioning. We suggest that the ecological effects of grazing by diversifying livestock species and breeds should be empirically tested across different grassland types worldwide, and each specific mode of diversifying livestock grazing should be explored in turn. Future studies should test the following key questions: (1) Can altering the proportion or grazing sequence of different livestock species help achieve optimal grazing by multiple livestock species? (2) How do introduced diverse livestock interact with native herbivores? (3) Can diverse livestock be used as a long-term ecological substitute for large wild herbivores to maintain grassland ecosystem functioning?

Expert Elicitation To Estimate the Feed Safety Impact of Criteria Included in the Canadian Food Inspection Agency Risk Assessment Model for Feed Mills

The Canadian Food Inspection Agency is developing an Establishment-based Risk Assessment (ERA) model for commercial and on-farm mills involved in the manufacture, storage, packaging, labeling, or distribution of livestock feed (ERA-Feed Mill model). This model will help inform the allocation of inspection resources on the basis of feed safety risk, including animal health and food safety risk. In a previous study, 34 risk factors, grouped into inherent, mitigation, and compliance clusters, along with assessment criteria were selected. The objective of this current study was to estimate the relative risk (RR) of the 203 assessment criteria on the basis of the impact on feed safety to design an ERA-Feed Mill model algorithm. Furthermore, the intent of this study was to assess the maximum increase or decrease of risk obtained when multiple criteria belonging to a same cluster were identified in a specific feed mill. To do so, a two-round face-to-face expert elicitation was conducted with 28 Canadian feed experts. Results showed no significant association between respondent profiles (years of experience and work sector) and estimated RR. Uniformity of answers between experts improved between rounds. Criteria having the highest increase in risk (median RR ≥ 4) included the presence of materials prohibited to be fed to ruminants in a facility that produces ruminant feed, the presence of multiple livestock species on-site, and historical noncompliances related to the inspection of the feed mill's process control and end-product control programs. Risk mitigation criteria having the highest impact on decreasing the risk were the implementation of feed safety certifications, the use of dedicated manufacturing lines (prohibited materials or medications), and having a hazard sampling plan in place for finished feed. The median RR assigned to each criterion and cluster will be used to build an algorithm of the Canadian Food Inspection Agency's ERA-Feed Mill model.

Antimicrobials use and resistance on integrated poultry-fish farming systems in the Ayeyarwady Delta of Myanmar

Antimicrobials are used to support livestock health and productivity, but might pose a risk for the development of antimicrobial resistance; in particular, when multiple livestock species are raised together in production systems. On integrated chicken-fish farms, chickens are raised over fish ponds and poultry faeces is excreted into the ponds. We investigated antimicrobial usage and the antimicrobial susceptibility of Escherichia coli cultured from poultry faeces on 301 integrated farms in Ayeyarwady Delta of Myanmar. Antimicrobials were used by 92.4% of farmers for chickens, but they were not applied to fish. The most common antimicrobials used were Octamix (amoxicillin and colistin sulfate) on 28.4%, enrofloxacin on 21.0% and amoxicillin on 16% of farms. Overall, 83.1% (152/183) of the E. coli were resistant to at least one antimicrobial. The highest level of resistance was to amoxicillin (54.6%), tetracycline (39.9%), sulfamethoxazole/trimethoprim (35.5%) and enrofloxacin (34.4%). Multidrug resistance was identified in 42.4% of isolates. In general, we found similar levels of antimicrobial resistance in non-users of antimicrobials as in users of antimicrobials for more commonly applied antimicrobials. Overall, antimicrobial resistance was lower in chickens on these integrated farms in Myanmar, compared to poultry farms in other countries of South East and East Asia.

Crop-livestock integrated systems for more sustainable agricultural production: a review.

Abstract Integrated crop-livestock systems have been proposed as a method to sustainably intensify agricultural systems. However, it is important to understand what is known about these systems and where potential gaps are in our current knowledge. I reviewed over 116 different research and review articles focused on integrated crop-livestock systems and based on their focus, divided them into one of the three different aspects of sustainability: environmental, economic, or social. Most of the 116 articles focused on environmental (77) or economic (72) aspects of integrated crop-livestock systems, with 42 articles having both environmental and economic aspects. Of the 32 articles focused on social issues, there were 17 articles that included both environmental and social aspects and 13 articles that evaluated both economic and social aspects of integrated crop-livestock systems. Only nine articles evaluated all three aspects of sustainability in crop-livestock systems. Most social articles focused on potential adoption strategies, but there was little information about the impact that integrated crop-livestock systems have on the social fabric of communities. Other areas of limited research included how the spatial arrangement of different components of integrated crop-livestock systems may affect system synergies and the inclusion of multiple livestock species, including monogastrics, into these systems.

Risks a la carte: Modelling the occurrence and intensity of wolf predation on multiple livestock species

Predation on livestock is a source of human-wildlife conflicts and can undermine the conservation of large carnivores. To design effective mitigation strategies, it is important to understand the determinants of predation across livestock species, which often differ in husbandry practices, vulnerability to predators and economic value. Moreover, attention should be given to both predation occurrence and intensity, because these can have different spatial patterns and predictors. We used spatial risk modelling to quantify factors affecting wolf predation on five livestock species in Portugal. Within the 1619 parishes encompassing the entire wolf range in the country, the national wolf compensation scheme recorded 17,670 predation events in 2009–2015, each involving one or more livestock species: sheep (31.7%), cattle (27.7%), goats (26.8%), horses (14.8%) and donkeys (3.2%). Models built with 2009–2013 data and validated with 2014–2015 data, showed a shared general pattern of predation probability on each species increasing with its own density and proximity to wolf packs. For some species there were positive relations with the density of other livestock species, and with habitat variables such as altitude, and land cover by shrubland and natural pastures. There was also a general pattern for predation intensity on each species increasing with its own density, while proximity to wolf packs had no significant effects. Predation intensity on goats, cattle and horses increased with the use of communal versus private pastures. Our results suggest that although predation may occur wherever wolves coexist with livestock species, high predation intensity is mainly restricted to particular areas where husbandry practices increase the vulnerability of animals, and this is where mitigation efforts should concentrate.

Lateral flow assay for brucellosis testing in multiple livestock species

Lateral flow assay (LFA) for brucellosis was standardized and evaluated. The test showed high diagnostic sensitivity, specificity and accuracy for diagnosis of brucellosis in bovines, small ruminants and swine. The study emphasized the importance of LFA as a useful, rapid, and easy-to-perform tool for the testing of brucellosis.

Comparative evaluation of blood based lateral flow assay for diagnosis of brucellosis in livestock species

Brucellosis is a zoonotic and economically important disease of livestock. Pen side diagnostics are the need of the hour for the rapid diagnosis of brucellosis. The present study aimed to evaluate blood based lateral flow assay (LFA) with serum based LFA and rose bengal plate test (RBPT) for diagnosis of brucellosis. Sera/blood samples [792: cattle, 153; buffalo, 55; sheep, 140; goats, 219; and pigs, 225] were collected from Karnataka, India with history of repeat breeding, retention of placenta and abortion.The seropositivity of brucellosis in cattle, buffalo, sheep, goats and pigs was 7.84, 3.63, 12.85, 2.73 and 39.11% by RBPT; 5.88, 3.63, 8.57, 2.73 and 31.1% by blood-LFA; and 7.18, 3.63, 10.71, 3.19 and 32.88% by serum-LFA. Relative specificity of blood based LFA was between 98.97 to 99.53% and 97.42 to 100% in comparison to serum-LFA and RBPT, respectively in all the species. The relative sensitivity for all the species ranged from 64.29 to 83.33% by blood-LFA and 57.14 to 84.09% by serum-LFA. The diagnostic accuracy of blood-LFA to RBPT and serum- LFA ranged from 91 to 99% among the species studied. It is opined that blood based LFA can serve as diagnostic test in place of serum based LFA for brucellosis screening in multiple livestock species and suggested for adaptation on-farm, slaughter, market, clinical and prepurchase surveillance of brucellosis in the country.

Characterization of a Broadly Reactive Anti-CD40 Agonistic Monoclonal Antibody for Potential Use as an Adjuvant.

Lack of safe and effective adjuvants is a major hindrance to the development of efficacious vaccines. Signaling via CD40 pathway leads to enhanced antigen processing and presentation, nitric oxide expression, pro-inflammatory cytokine expression by antigen presenting cells, and stimulation of B-cells to undergo somatic hypermutation, immunoglobulin class switching, and proliferation. Agonistic anti-CD40 antibodies have shown promising adjuvant qualities in human and mouse vaccine studies. An anti-CD40 monoclonal antibody (mAb), designated 2E4E4, was identified and shown to have strong agonistic effects on primary cells from multiple livestock species. The mAb recognize swine, bovine, caprine, and ovine CD40, and evoked 25-fold or greater proliferation of peripheral blood mononuclear cells (PBMCs) from these species relative to cells incubated with an isotype control (p<0.001). In addition, the mAb induced significant nitric oxide (p<0.0001) release by bovine macrophages. Furthermore, the mAb upregulated the expression of MHC-II by PBMCs, and stimulated significant (p<0.0001) IL-1α, IL6, IL-8, and TNF-α expression by PBMCs. These results suggest that the mAb 2E4E4 can target and stimulate cells from multiple livestock species and thus, it is a potential candidate for adjuvant development. This is the first study to report an anti-swine CD40 agonistic mAb that is also broadly reactive against multiple species.

Genotyping of Indian antigenic, vaccine, and field Brucella spp. using multilocus sequence typing.

Brucellosis is one of the most important zoonotic diseases that affects multiple livestock species and causes great economic losses. The highly conserved genomes of Brucella, with > 90% homology among species, makes it important to study the genetic diversity circulating in the country. A total of 26 Brucella spp. (4 reference strains and 22 field isolates) and 1 B. melitensis draft genome sequence from India (B. melitensis Bm IND1) were included for sequence typing. The field isolates were identified by biochemical tests and confirmed by both conventional and quantitative polymerase chain reaction (qPCR) targeting bcsp 31Brucella genus-specific marker. Brucella speciation and biotyping was done by Bruce ladder, probe qPCR, and AMOS PCRs, respectively, and genotyping was done by multilocus sequence typing (MLST). The MLST typing of 27 Brucella spp. revealed five distinct sequence types (STs); the B. abortus S99 reference strain and 21 B. abortus field isolates belonged to ST1. On the other hand, the vaccine strain B. abortus S19 was genotyped as ST5. Similarly, B. melitensis 16M reference strain and one B. melitensis field isolate were grouped into ST7. Another B. melitensis field isolate belonged to ST8 (draft genome sequence from India), and only B. suis 1330 reference strain was found to be ST14. The sequences revealed genetic similarity of the Indian strains to the global reference and field strains. The study highlights the usefulness of MLST for typing of field isolates and validation of reference strains used for diagnosis and vaccination against brucellosis.

Vaccination control programs for multiple livestock host species: an age-stratified, seasonal transmission model for brucellosis control in endemic settings.

BackgroundBrucella melitensis causes production losses in ruminants and febrile disease in humans in Africa, Central Asia, the Middle East and elsewhere. Although traditionally understood to affect primarily sheep and goats, it is also the predominant Brucella species that affects cows in some endemic areas. Despite this, no licensed vaccine is available specifically for use against B. melitensis in cows. The mainstay of most control programs is vaccination of sheep and goats with a live vaccine, Rev-1. The aim of this study was to investigate how critical vaccination of cows might be, in order to control B. melitensis on a mixed sheep-and-cattle farm.MethodsA dynamic, differential-equation, age-structured, seasonal model with births and deaths, was used to investigate whether vaccination of both sheep and cattle had an impact on time to elimination of brucellosis on an individual mixed species farm, when compared to vaccination of sheep only. The model was a Susceptible-Exposed-Infectious-Recovered-Susceptible (SEIRS) model with an additional compartment for Persistently Infected (PI) individuals. Transmission parameters were fit based on a nation-wide probabilistic seroprevalence survey in Jordan.ResultsThe model predicted that it would take 3.5 years to eliminate brucellosis (to less than 0.5 % of adult sheep seropositive as a result of infection) on a mixed-species B. melitensis-endemic farm with the median field-study seroprevalence, following vaccination of both sheep and cattle, assuming a vaccine effectiveness of 80 %. Limiting the vaccination to sheep only, increased the time to 16.8 years. Sensitivity analysis showed that the finding that vaccination of cattle was of significant importance, was robust. Vaccine effectiveness had a strong influence on time to elimination.ConclusionsIn the absence of further data, vaccination of cattle should be considered essential in Brucella-endemic settings where mixed small ruminant and cattle flocks predominate. Further evidence that Brucella melitensis predominates in cattle in Jordan, as opposed to Brucella abortus, is needed in order to validate this model. The results may be applicable to other mixed-species settings with similar livestock management practices. These methods may be applied to other pathogens affecting multiple livestock species or with seasonal transmission.

Public health knowledge and attitudes in rural Vietnam and mitigation strategies

Background: Integrated management of multiple livestock species, aquaculture, and crops has been a part of rural Vietnam for centuries and is formally promoted by the Ministry of Agriculture. However, management methods may be contributing to the emergence of zoonotic diseases of recent concern (e.g., avian influenza and coliform diseases). This suggests a need for change in public health awareness and farm management. Methods & Materials: We used farm visits, questionnaires, focus groups, and analysis of water samples to investigate the public health knowledge, livestock management, and association with presence of coliform bacteria on 600 small scale integrated farms in north (Thai Binh) and south (An Giang) Vietnam in 2013. Water samples were analyzed in national government laboratories for E. coli as an indicator organism for fecal contamination of water using culture and tryptose broth methods. Questionnaire and focus group data were analyzed using summary statistics, probit regression, and clustering techniques for qualitative data. Results: More than 80% (p < .01) of drinking and household water samples from 600 homes in the sampling frame tested positive for E. coli at unsafe levels exceeding WHO standards (0 cfu/100 ml for drinking water and 6 cfu/100 ml for household water). Presence of E. coli in drinking water ranged from 0 to 500 cfu/100 ml (mean = 10, s.d. = 39.6). Farmers expressed high level awareness (>90%) that avian influenza or parasites could spread from livestock via water but low level awareness that bacteria such as E. coli could spread from livestock to humans via water. Although a majority of farmers (>70%) indicated they filter and/or boil their drinking water, other basic mitigation strategies such hand washing or preventing mixing of livestock was not common. Conclusion: In general, the presence of E. coli in drinking water was unacceptably high in most households we sampled in Thai Binh and An Giang provinces in Vietnam. Although farmers revealed some intuitive knowledge of public health, farm management procedures such as incomplete separation of livestock are likely to contribute to cross-contamination of drinking and household water. Basic public health training is recommended to help farmers appreciate the benefits of simple mitigation strategies.

Seroepidemiological study of livestock brucellosis in a pastoral region

A seroepidemiological study of Brucella infections in multiple livestock species in the Borana pastoral system of Ethiopia was performed between December 2007 and October 2008. A cross-sectional multi-stage sampling technique was employed to select 575 cattle, 1073 camels and 1248 goats from the target populations. Sera were collected from the animals, and serially tested using Rose Bengal test and complement fixation test. Overall prevalence and prevalence with respect to explanatory variables were established, and potential risk factors for seropositivity were analysed using a multivariable logistic regression. The results showed that 8·0% (95% CI 6·0-10·6), 1·8% (95% CI 1·1-2·8) and 1·6% (95% CI 1·0-2·5) of the tested cattle, camels and goats, respectively, had antibodies to Brucella antigen. Positive reactors were found in 93·8% of the villages with more frequent detection of positive cattle (93·3%) than camels (56·3%) and goats (37·5%). Risk factors identified for cattle were: keeping more livestock species at household level (OR 4·1, 95% CI 1·9-8·9), increasing age of the animal (OR 2·8, 95% CI 1·3-6·0) and wet season (OR 3·3, 95% CI 1·6-6·9). Increase in household-level species composition (OR 4·1, 95% CI 1·2-14·2) and wet season (OR 3·7, 95% CI 1·5-9·1) were found to be risk factors for seropositivity in camels and goats, respectively. Existence of more than one seroreactor animal species in most villages and association of increased livestock species composition with seropositivity may add more credence to the possibility of cross-species transmission of Brucella infections. Although no attempt to isolate Brucella spp. was made, our results suggest that cattle are more likely maintenance hosts of Brucella abortus which has spread to goats and camels. This should be substantiated by further isolation and identification of Brucella organisms to trace the source of infection and transmission dynamics in various hosts kept under mixed conditions. In conclusion, the present study suggests the need for investigating a feasible control intervention and raising public awareness on prevention methods of human exposure to brucellosis.