Prevalence and molecular characterisation of Eimeria species in Ethiopian village chickens

Molecular phylogenetic analysis and seasonal dynamics of Eimeria species infecting broilers of Kashmir, India

Globally, the poultry industry is seriously threatened by coccidiosis caused by various species of Eimeria. This protozoan parasite inhabits the epithelial lining of the gastrointestinal tract of poultry globally and can cause serious clinical disease. The present study was carried out on poultry farms located in various regions of Kashmir, India, to investigate the prevalence and phylogenetic relationships of Eimeria species affecting broiler chickens. Over a period of one year, fecal samples were collected from 60 poultry farms in Kashmir and morphological and molecular techniques were employed for Eimeria species identification. Results revealed a high prevalence of coccidiosis, with 58.3% (35/60) of farms positive for Eimeria. The most prevalent species were E. tenella (31/35, 88.6%) followed by E. acervulina (25/35, 71.4%), E. maxima (19/35, 54.3%), E. mitis (18/35, 51.4%), and E. necatrix (9/35, 25.7%). Seasonal variation in prevalence was also observed, with the highest rates in autumn (86.7%) and summer (66.7%). Additionally, younger birds (3-4 weeks) exhibited higher infection rates (85.7%) compared to older birds (57.9%) (5-6 weeks). Mixed infection was found in 94.2% (33/35) of positive farms. Phylogenetic analysis using ITS1 sequences confirmed species clustering and revealed evolutionary relationships among Eimeria species. E. tenella and E. necatrix formed a distinct clade, while E. acervulina formed another. The study underscores the importance of molecular techniques in accurate species identification and provides valuable insights into the epidemiology of coccidiosis in poultry in Kashmir. Effective control strategies, including vaccination and improved management practices, are necessary to mitigate the economic losses associated with this widespread poultry disease.

Prediction of coccidiosis prevalence in extensive backyard chickens in countries and regions of the Horn of Africa

Coccidiosis is one of the leading morbidity causes in chickens, causing a reduction of body weight and egg production. Backyard chickens are at risk of developing clinical and subclinical coccidiosis due to outdoor housing and scavenging behaviour, jeopardizing food security in households. The objectives of this study were to estimate clinical prevalence of coccidiosis at country and regional levels in the Horn of Africa in extensive backyard chickens. A binomial random effects model was developed to impute prevalence of coccidiosis. Previously gathered prevalence data (n = 40) in backyard chickens was used to define the model. Precipitation (OR: 1.09 (95% CI: 1.05-1.13) and the presence of seasonal rainfall (OR: 1.85, 95% CI: 1.27-2.70) significantly increase prevalence. Results showed an overall prevalence of coccidiosis in the Horn of Africa of 0.21 (95% CI: 0.15-0.29). Ethiopia, the Republic of South Sudan and Kenya showed the highest prevalence and Djibouti the lowest. Significant differences between Djibouti and the countries with highest prevalence were found. However, no evidence of a significant difference between the rest of the countries. Kenya and Ethiopia showed larger prevalence differences between regions. Results could assist with the targeting of testing for coccidiosis, the observation for clinical disease of chickens living in specific regions and as a baseline for the evaluation of future control measures.

Bioactive Components of Areca Nut: An Overview of Their Positive Impacts Targeting Different Organs

Areca catechu L. is a widely cultivated tropical crop in Southeast Asia, and its fruit, areca nut, has been consumed as a traditional Chinese medicinal material for more than 10,000 years, although it has recently attracted widespread attention due to potential hazards. Areca nut holds a significant position in traditional medicine in many areas and ranks first among the four southern medicines in China. Numerous bioactive compounds have been identified in areca nuts, including alkaloids, polyphenols, polysaccharides, and fatty acids, which exhibit diverse bioactive functions, such as anti-bacterial, deworming, anti-viral, anti-oxidant, anti-inflammatory, and anti-tumor effects. Furthermore, they also display beneficial impacts targeting the nervous, digestive, and endocrine systems. This review summarizes the pharmacological functions and underlying mechanisms of the bioactive ingredients in areca nut. This helps to ascertain the beneficial components of areca nut, discover its medicinal potential, and guide the utilization of the areca nut.

Application of structural equation modelling to inform best management strategies for Marek's disease in Amhara region, Ethiopia

Marek's disease, a highly contagious and an economically significant oncogenic and paralytic viral diseases of poultry, is becoming a serious problem in Ethiopia's poultry sector. The aim of the study was to examine the relationship between risk factors and their contribution to develop risk with the intentions to implement MD control measures in the different chicken production systems of Ethiopia using the SEM framework. A questionnaire was designed based on the framework and each model constructed was measured using a set of rating scale items. Thus, a sample size of 200 farmers from different production systems were chosen for the data collection. From the analysis, Cornbrash's Alpha (coefficient of reliability) based on the average inter-item correlations were evaluated for each parameter. The result showed that when litter management goes up by 1, the number of sick goes down by 37.575, the number of staff goes up by 1, the number of sick goes down by 7.63, litter management goes up by 1, the number of deaths goes down by 2.505, flock size goes up by 1, the number of deaths goes down by 0.007 than the rest of the activities. The result of this structural equation modeling finding indicates that the data fit the model well (χ2 = 0.201, RMSEA = 0.000, CFI = 1.00, TLI = 1.496, Degrees of freedom = 2) and the model was appropriated. In conclusion, flock size, litter management and number of staff activities have more impact on the numbers of sick, drops in egg production and the number of deaths. Therefore, practicing regular awareness creation for producers regarding management techniques is recommended.

Transverse study of Eimeria spp. infection in broiler and layer chickens in central Kashmir

The present study was carried out to isolate and identify various species of Eimeria and to study overall prevalence of coccidiosis in central Kashmir (Srinagar, Ganderbal and Budgam). A total of 45 outbreaks, 15 from each district, of coccidiosis in chicken were recorded over the period of two years. A total of 15, 15, 10 and 5 outbreaks were recorded in chicken of 2-3, 3-4, 4-5 weeks of age and layers, respectively. The overall mortality in the flocks was 2.6%, with the highest mortality of 3.2% recorded in the age group of 3-4 weeks. An overall prevalence of coccidiosis among the total necropsies was 10.63%. A total of seven different species of Eimeria were identified in broilers and layers namely E. tenella, E. acervulina, E. maxima, E. necatrix, E. mitis, E. praecox and E. brunetti. Among these species, E. tenella (39.7%) was recorded with highest and E. brunetti (3.1%) with lowest prevalence in broilers, whereas, in case of layers E. necatrix (27.7%) recorded highest and E. mitis, E. praecox and E. brunetti (2.7%) recorded the lowest prevalence. Morphometrically, oocyst of Eimeria maxima (30.4 × 20.8 μm) and Eimeria mitis (16.21 × 16.0 μm) exhibited the largest and smallest sizes, respectively. Most of the Eimeria species had a sporulation time of 18 h with highest in Eimeria maxima (30 h) and lowest in E. praecox (12 h).

Phenotypical Identification and Toxinotyping of Clostridium perfringens Isolates from Healthy and Enteric Disease-Affected Chickens

Clostridium perfringens is a ubiquitous spore-forming anaerobic pathogen that is frequently associated with enteric disease in chickens. Moreover, enterotoxin-producing C. perfringens has high zoonotic potential as well as serious public health concerns due to the emanation of food-borne intoxication. The present study was designed to isolate, identify, and toxinotype C. perfringens from both healthy and cases of necrotic or ulcerative enteritis chickens. A total of 110 samples were collected from July 2019 to February 2021. Among the samples, 38 (34.5%, 95% CI: 26.39-43.83) were positive for C. perfringens and were obtained from broiler 21 (33.3%, 95% CI: 22.91-45.67), Sonali 9 (34.6%, 95% CI: 19.31-53.88), and layer 8 (38%, 95% CI: 20.68-59.20). C. perfringens was highly prevalent (35.7%, 95% CI: 25.48-47.44) in enteritis chickens compared with healthy ones. In multiplex PCR toxinotyping, 34 (89.4%) isolates were identified as C. perfringens type A by the presence of the alpha toxin gene (cpa). Moreover, in addition to the cpa gene, 3 (14.3%, 95% CI: 4.14-35.48) broiler and 1 (11.1%, 95% CI: 0.01-45.67) Sonali isolates harbored the enterotoxin gene (cpe) and were classified as type F. However, none of the isolates carried genes encoding beta (cpb), epsilon (etx), iota (iap), or beta-2 (cpb2) toxins. Multivariable logistic regression analysis identified the following variables such as; "previously used litter materials" (OR 21.77, 95% CI 2.22-212.66, p ≤ 0.008); intestinal lesions, "presence of ulceration" (OR 30.01, 95% CI 3.02-297.91, p ≤ 0.004); "ballooned with gas" (OR 24.74, 95% CI 4.34-140.86, p ≤ 0.001) and "use of probiotics" (OR 5.24, 95% CI 0.74-36.75, p ≤ 0.095) act as risk factors for C. perfringens colonization in chicken gut. This is the first study of molecular toxinotyping of C. perfringens from healthy and enteric-diseased chickens in Bangladesh, which might have a potential food-borne zoonotic impact on human health.

Prevalence and pathology of Cephalopina titillator infestation in Camelus bactrianus from Xinjiang, China

BACKGROUND

In camels, nasopharyngeal myiasis is caused by the larvae of Cephalopina titillator, which parasitize the tissues of nasal and paranasal sinuses, pharynx, and larynx. C. titillator infestation adversely affects the health of camels and decreases milk and meat production and even death. However, the C. titillator infestation in Bactrian camels has not been widely studied.

METHODS

The present study was conducted to determine the prevalence and risk factors of C. titillator in Bactrian camels of northwestern Xinjiang. Suspected larvae recovered from infested camels were evaluated for C. titillator by microscopy and polymerase chain reaction. Nucleotide sequences of the partial mitochondrial cytochrome c oxidase subunit I (COX1) and cytochrome b (CYTB) genes from the C. titillator of camels were aligned from the NCBI database. Furthermore, the gross and histopathological alterations associated with C. titillator infestation were evaluated via pathological examination.

RESULTS

Of 1263 camels examined 685 (54.2%) camels were infested with suspected C. titillator larvae. Different larval stages were topically detected in the nasal passages and pharynx of the camel heads. Microscopy analysis of the pharyngeal mucosa tissue revealed necrotic tissue debris and some inflammatory cells. Molecular detection of the larval COX1 and CYTB genes indicated that pathogen collected in Bactrian camels was C. titillator. The epidemiological study demonstrated that the prevalence rate of C.titillator infestation was significantly higher in camels of Bestierek Town Pasture (67.2%) and Karamagai Town Pasture (63.6%) compared to Kitagel Town Pasture (38.7%) and Qibal Town Pasture (35.8%) (P < 0.05). No significant difference was observed between the prevalence rates in male (52.6%) and female (54.6%) camels (P > 0.05). The prevalence was higher in warm (64.2%) than that in cold (48.4%) seasons (P < 0.001). The prevalence in camels with non-nomadic method (67.2%) was significantly higher than in animals with nomadic method (47.5%) (P < 0.001). The prevalence of C.titillator infestation was significantly higher in animals of aged 5-10 (60.1%) and aged > 10 (61.1%) years old compared to those of aged < 5 (31.7%) years old camels (P < 0.001).

CONCLUSION

Our results confirm that there is a high prevalence of C. titillator in Bactrian camels from Xinjiang, closely related to age, season, pasture environment, and husbandry methods. Developing prevention, diagnosis, and control programs to prevent transmission is necessary.

Molecular Characterization of Eimeria Species in Broiler Chickens, Ethiopia

Background

Eimeria is a parasitic organism causing coccidiosis, an enteric disease of major economic importance in poultry. The conventional methods for species identification of Eimeria have major limitations.

Methods

Fresh fecal samples were randomly collected from 50 small and large-scale commercial broiler farms located in Adama, Bishoftu, Dukem, and Mojo towns. Polymerase chain reaction (PCR)-based assay was used for the differentiation of Eimeria species circulating among study sites and broiler farms. DNA was extracted from Eimeria oocytes using a DNeasy Tissue Kit. The extracted DNA templates and the genus-specific primers (Invitrogen) were used for the amplification of the ITS-1 region from seven Eimeria species of chicken. Descriptive statistical analysis and t-test were used to summarize and analyze the data.

Results

The PCR result confirms that all the seven species of Eimeria were detected in both small and large-scale broiler farms. Prevalence variation was found among broiler farms and between study sites. The frequency of E. brunetti (P<0.006) and E. tenella (P<0.04) in the small-scale broiler farms was significantly higher compared to that of in large-scale farms. A significantly higher frequency of E. acervulina (P<0.03) and E. brunetti (P<0.03) was detected in broiler farms of Dukem and Mojo compared to the broiler farms in Bishoftu. The study also revealed that multiple infections of Eimeria species per sample are common in most farms. Among the evaluated small-scale broiler farms of Bishoftu, 80% showed up to 5 mixed species. In addition, about 33% of large-scale and 20% of small-scale broiler farms showed 6–7 mixed species.

Conclusion

This study characterized all the seven Eimeria species and revealed that multiple infections of Eimeria species per sample are common in most of the evaluated farms. The current findings might be useful for future anticoccidial vaccine development and for effective chemoprophylactic and control strategies.

Controlling the causative agents of coccidiosis in domestic chickens; an eye on the past and considerations for the future

Coccidiosis is a potentially severe enteritis caused by species of obligate intracellular parasites of the genus Eimeria. These parasites cause significant economic losses to the poultry industry, predominantly due to compromised efficiency of production as well as the cost of control. These losses were recently estimated to cost chicken producers approximately £10.4 billion worldwide annually. High levels of Eimeria infection cause clinical coccidiosis which is a significant threat to poultry welfare, and a pre-disposing contributory factor for necrotic enteritis. Control of Eimeria parasites and coccidiosis is therefore an important endeavour; multiple approaches have been developed and these are often deployed together. This review summarises current trends in strategies for control of Eimeria, focusing on three main areas: good husbandry, chemoprophylaxis and vaccination. There is currently no "perfect solution" and there are advantages and limitations to all existing methods. Therefore, the aim of this review is to present current control strategies and suggest how these may develop in the future.

Prioritizing smallholder animal health needs in East Africa, West Africa, and South Asia using three approaches: Literature review, expert workshops, and practitioner surveys

Managing the health needs of livestock contributes to reducing poverty and improving the livelihoods of smallholder and pastoralist livestock keepers globally. Animal health practitioners, producers, policymakers, and researchers all must prioritize how to mobilize limited resources. This study employed three approaches to prioritize animal health needs in East and West Africa and South Asia to identify diseases and syndromes that impact livestock keepers. The approaches were a) systematic literature review, b) a series of expert workshops, and c) a practitioner survey of veterinarians and para-veterinary professionals. The top constraints that emerged from all three approaches include endo/ ectoparasites, foot and mouth disease, brucellosis, peste des petits ruminants, Newcastle disease, and avian influenza. Expert workshops additionally identified contagious caprine pleuropneumonia, contagious bovine pleuropneumonia, mastitis, and reproductive disorders as constraints not emphasized in the literature review. Practitioner survey results additionally identified nutrition as a constraint for smallholder dairy and pastoralist small ruminant production. Experts attending the workshops agreed most constraints can be managed using existing veterinary technologies and best husbandry practices, which supports a shift away from focusing on individual diseases and new technologies towards addressing systemic challenges that limit access to veterinary services and inputs. Few research studies focused on incidence/ prevalence of disease and impact, suggesting better incorporation of socio-economic impact measures in future research would better represent the interests of livestock keepers.

Study on the prevalence and genetic diversity of Eimeria species from broilers and free-range chickens in KwaZulu-Natal province, South Africa

This study was conducted from January to October 2018 with the objective to determine the prevalence and genetic diversity of Eimeria species in broiler and free-range chickens in KwaZulu-Natal province, South Africa. A total of 342 faecal samples were collected from 12 randomly selected healthy broiler chicken farms and 40 free-range chickens from 10 different locations. Faecal samples were screened for the presence of Eimeria oocysts using a standard flotation method. The species of Eimeria isolates were confirmed by amplification of the internal transcribed spacer 1 (ITS-1) partial region and sequences analysis. Among broiler and free-ranging chickens, 19 out of 41 pens (46.3%) and 25 out of 42 faecal samples (59.5%) were positive for Eimeria infection. Molecular detection revealed the following species: Eimeria maxima, Eimeria tenella, Eimeria acervulina, Eimeria brunetti and Eimeria mitis in all the samples screened. Similarly, polymerase chain reaction assays specific for three cryptic Eimeria operational taxonomic units were negative for all the samples. Phylogenetic analysis of the ITS-1 sequences supported species identity with the greatest variation detected for E. mitis. This study provides information on the range and identity of Eimeria species, and their genetic relatedness, circulating in commercially reared broilers and free-ranging chickens from different locations in KwaZulu-Natal province.

Infectious and parasitic diseases of poultry in Ethiopia: a systematic review and meta-analysis

In Ethiopia, poultry production is an important source of domestic food and nutrition security while providing income for nearly 80% of Ethiopians. However, several infectious and parasitic diseases hamper poultry production. To date, evidence on the nationwide burden of specific diseases has not been collated to inform targeting of poultry health interventions. The objective of this systematic review is to summarize and analyze the literature on poultry diseases since 2000. A detailed systematic review protocol was designed according to Cochrane collaboration, Strengthening the Reporting of Observational Studies in Epidemiology (STROBE), and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statements. The review revealed that 14 infectious and parasitic diseases of poultry were reported in 110 published studies from 2000 to 2017, and 81.82% (90/110) of the studies covered 6 diseases: Newcastle disease (ND), infectious bursal disease (IBD), avian coccidiosis, helminth infestation, ecto-parasite infestation, and Salmonella infection. The pooled prevalence estimates of ND and IBD were 44% (95% confidence interval [CI]: 27 to 63) and 41% (95% CI: 23 to 60), respectively. Among the parasitic diseases, avian coccidiosis, helminth infestation, and ecto-parasite infestation had estimated pooled prevalences of 37% (95% CI: 30 to 44), 62% (95% CI: 45 to 78), and 50% (95% CI: 33 to 68), respectively. The pooled prevalence estimate of Salmonella infection was found to be 51% (95% CI: 32 to 70). Most of the studies were conducted in central Ethiopia, in the State of Oromia, and focused on extensive farming systems. While the number of studies was low, the overall trend of disease reporting in the literature is increasing (Y = 0.99X-3.34). In conclusion, the high-pooled prevalence estimates of diseases and the scarcity of reported data for all of Ethiopia indicate an important data gap on infectious-disease distribution in the country. While the high-pooled prevalence points towards the need for intervention to control poultry diseases, there is also a need to ensure all diseases that result in production losses and public health risks are studied appropriately in all Ethiopian production systems.

Quantification of Eimeria necatrix, E. acervulina and E. maxima genomes in commercial chicken farms by quantitative real time PCR

Advent of quantitative polymerase chain reaction and its variants have enabled identification and quantification of seven known Eimeria species of poultry in biological samples. Attempts were made in the present study to identify and quantify three important pathogenic Eimeria species responsible for intestinal coccidiosis in domestic farmed chicken, E. necatrix, E. acervulina and E. maxima in droppings collected from thirty one poultry farms of North Indian states of Haryana, Punjab, Uttar Pradesh and Uttarakhand. The study included broiler, layer and backyard rearing units. Overall occurrence of E. necatrix, E. maxima and E. acervulina was 64.5%. E. necatrix was detected in 55% (11/20) broiler farms, 66.7% (4/6) layer farms and 100% (5/5) backyard rearing units studied. Thus, occurrence of E. necatrix was detected in 64.5% (20/31) farms studied. E. maxima and E. acervulina were detected in droppings of 65% (13/20) broiler farms, 66.7% (4/6) layer farms and 60% (3/5) back yard rearing units. Genome counts of each Eimeria species revealed maximum parasite load of E. necatrix followed by E. acervulina in broiler farms and least in layer farms. The mean parasite load (genome) copies for these parasite species were intermediate for backyard units while E. maxima had the lowest number of genome copies in droppings. Mean E. maxima counts were highest in boiler farms, while it was similar for layer and back yard units. However, statistically no significant differences were observed for parasite load existing either between the broiler, layer or back yard units or between the genome counts of E. necatrix, E. acervulina or E. maxima.

The role of local adaptation in sustainable village chicken production

Village chickens are ubiquitous in smallholder farming systems, contributing to household, local and national economies under diverse environmental, economic and cultural settings. However, they are raised in challenging environments where productivity is low while mortality is high. There is much interest in utilizing indigenous genetic resources to produce a chicken resilient to its environment, whilst providing the basis of an economically sustainable enterprise. Globally, however, a wide variety of interventions have so far proved unable to deliver sustainable improvements. Here, we show that regional differences in trait preferences and parasite burden are associated with distinct chicken genepools, likely in response to interacting natural and human-driven (economic and social) selection pressures. Drivers of regional differences include marketing opportunities, cultural preferences, agro-ecologies and parasite populations, and are evident in system adaptations, such as management practices, population dynamics and bird genotypes. Our results provide sound multidisciplinary evidence to support previous observations that sustainable poultry development interventions for smallholder farmers, including breeding programs, should be locally tailored and designed for flexible implementation.

Populations of Eimeria tenella express resistance to commonly used anticoccidial drugs in southern Nigeria

Coccidiosis is one of the most economically important diseases of poultry. This study determined the preponderance of chicken Eimeria in southern Nigeria and assessed the parasite's resistance to three anticoccidial drugs: Amprolium hydrochloride; Amprolium hydrochloride + Sulfaquinoxaline-Sodium; and Toltrazuril. Multiplex PCR amplification of the SCAR region was used to confirm Eimeria preponderance. Resistance was assessed following the inoculation of 2.32 × 10⁵ infective oocysts into broilers. Data on weight gain, feed intake, feed conversion and fecal oocyst shed were recorded. At 7 days post inoculation 9 birds per treatment were sacrificed and assessed for macroscopic lesions in four intestinal regions. Percent optimum anticoccidial activity (POAA), Anticoccidial index (ACI) and Anticoccidial sensitivity test (AST) were used to access resistance. The preponderance of Eimeria spp. were E. tenella (77%), E. necatrix (55%), E. acervulina (44%) and E. mitis (11%), with multi-species infection occurring in 55% of samples assessed. Fecal oocyst shedding was low (P < 0.05) in the medicated groups. Lesions in the cecal region were present in all infected groups regardless of treatment and accounted for 27.8% of lesion scores by severity and 37.5% of lesion scores by frequency. Overall, lesion scores were less (P < 0.05) in birds of the medicated groups compared with the infected-unmedicated group. The high preponderance of E. tenella in the field, and the occurrence of cecal lesions - caused mainly by E. tenella- despite drug administration, indicate resistance in populations of this species in our isolate. Based-on the POAA, ACI and AST values, the Eimeria isolate showed reduced sensitivity to toltrazuril.

Eimeria species occurrence varies between geographic regions and poultry production systems and may influence parasite genetic diversity

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Multivariate analysis revealed comparable poultry clusters in north and south India.

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Eimeria species occurrence varied between system clusters.

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E. tenella occurrence across systems may underpin region-specific genetic diversity.

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E. necatrix was found to be more common in north than south India.

Coccidiosis is one of the biggest challenges faced by the global poultry industry. Recent studies have highlighted the ubiquitous distribution of all Eimeria species which can cause this disease in chickens, but intriguingly revealed a regional divide in genetic diversity and population structure for at least one species, Eimeria tenella. The drivers associated with such distinct geographic variation are unclear, but may impact on the occurrence and extent of resistance to anticoccidial drugs and future subunit vaccines. India is one of the largest poultry producers in the world and includes a transition between E. tenella populations defined by high and low genetic diversity. The aim of this study was to identify risk factors associated with the prevalence of Eimeria species defined by high and low pathogenicity in northern and southern states of India, and seek to understand factors which vary between the regions as possible drivers for differential genetic variation. Faecal samples and data relating to farm characteristics and management were collected from 107 farms from northern India and 133 farms from southern India. Faecal samples were analysed using microscopy and PCR to identify Eimeria occurrence. Multiple correspondence analysis was applied to transform correlated putative risk factors into a smaller number of synthetic uncorrelated factors. Hierarchical cluster analysis was used to identify poultry farm typologies, revealing three distinct clusters in the studied regions. The association between clusters and presence of Eimeria species was assessed by logistic regression. The study found that large-scale broiler farms in the north were at greatest risk of harbouring any Eimeria species and a larger proportion of such farms were positive for E. necatrix, the most pathogenic species. Comparison revealed a more even distribution for E. tenella across production systems in south India, but with a lower overall occurrence. Such a polarised region- and system-specific distribution may contribute to the different levels of genetic diversity observed previously in India and may influence parasite population structure across much of Asia and Africa. The findings of the study can be used to prioritise target farms to launch and optimise appropriate anticoccidial strategies for long-term control.

Improving animal health for poverty alleviation and sustainable livelihoods

Animals are vital to ensuring food security for individuals, families and communities in countries around the world. In this, the latest article in Veterinary Record's series promoting One Health, Andy Stringer, director of veterinary programmes at the Society for the Protection of Animals Abroad, discusses how improving animal health, particularly of poultry and working equids, has the potential to reduce poverty and promote food security and sustainable livelihoods in low-income countries.

Infection-interactions in Ethiopian village chickens

Chickens raised under village production systems are exposed to a wide variety of pathogens, and current or previous infections may affect their susceptibility to further infections with another parasite, and/or can alter the manifestation of each infection. It is possible that co-infections may be as important as environmental risk factors. However, in cross-sectional studies, where the timing of infection is unknown, apparent associations between infections may be observed due to parasites sharing common risk factors. This study measured antibody titres to 3 viral (Newcastle disease, Marek's disease and infectious bursal disease) and 2 bacterial (Pasteurella multocida and Salmonella) diseases, and the infection prevalence of 3 families of endo- and ecto-parasites (Ascaridida, Eimeria and lice) in 1056 village chickens from two geographically distinct populations in Ethiopia. Samples were collected during 4 cross-sectional surveys, each approximately 6 months apart. Constrained ordination, a technique for analysis of ecological community data, was used to explore this complex dataset and enabled potential relationships to be uncovered and tested despite the different measurements used for the different parasites. It was found that only a small proportion of variation in the data could be explained by the risk factors measured. Very few birds (9/1280) were found to be seropositive to Newcastle disease. Positive relationships were identified between Pasteurella and Salmonella titres; and between Marek's disease and parasitic infections, and these two groups of diseases were correlated with females and males, respectively. This may suggest differences in the way that the immune systems of male and female chickens interact with these parasites. In conclusion, we find that a number of infectious pathogens and their interactions are likely to impact village chicken health and production. Control of these infections is likely to be of importance in future development planning.