A comparison of the prevalence and burdens of helminth infections in growers and adult free-range chickens

Diversity of Parasitic Fauna in Semi-Scavenging Indigenous Chickens (Gallus gallus domesticus) in Bangladesh

BACKGROUND

Parasites are a major concern for profitable poultry production worldwide as they impede the health, welfare and production performance of poultry.

OBJECTIVES

The present study was designed to detect the diversity of parasitic fauna and associated factors of gastrointestinal (GI) helminths and lice in indigenous chickens.

METHODS

A total of 310 indigenous chickens were collected from different villages at Gauripur and Mymensingh Sadar, Mymensingh, and Bangladesh, and various parasites were identified.

RESULTS

Out of 310 indigenous semi-scavenging chickens, 281 were infected with one or more species of helminths with an overall prevalence of 90.6%. The identified species of helminths were Ascaridia galli (60.6%), Heterakis gallinarum (29.0%) and Cheilospirura hamulosa (14.2%), Catatropis verrucosa (7.7%), Echinostoma revolutum (7.4%), Raillietina spp. (76.5%) and Hymenolepis spp. (5.8%). The prevalence of lice infestations was 74.2%, and identified species were Menopon gallinae (72.6%), Goniodes gigas (11.6%) and Lipeurus caponis (10.3%). Co-infections with helminths were 65.8% and with lice were 19.4% in chickens. Univariate analysis was performed to measure the association between predictor variables and parasitic infections by considering several biotic and abiotic variables, including age, sex, flock size, farming nature, use of anthelmintic/insecticides and socio-economic status of owners. No significant (p < 0.05) variation was found in helminth infections but large flock size (87.0%) and mixed farming nature (81.2%) were significantly associated with lice infestations in chickens.

CONCLUSIONS

Awareness related to the management system of chickens rearing need to be increased for formulating control strategy against parasitic infections in indigenous chickens in Bangladesh.

Global and regional prediction of heterakidosis population prevalence in extensive backyard chickens in low-income and middle-income countries

Extensive backyard chickens are one of the most common production systems in low-income and middle-income countries (LMICs). In this production system, chickens are exposed to infectious forms of parasites as a result of the outdoor access and scavenging behaviour. Heterakis gallinarum is one of the most common nematode parasites present in the environment, and estimating its global and regional prevalence is essential for attributing the economic losses in extensive backyard chickens. The objective of this study is to predict the prevalence of heterakidosis in extensive backyard chickens at global and regional levels in LMICs using regression imputation methods. A binomial random effect model was developed using empirical data on heterakidosis prevalence and climatic factors as main predictors. Prevalence data were then imputed in all regions based on the regression model. Global and country prevalence were estimated based on regional predictions and their beta distributions. Minimum precipitation, minimum temperature and maximum temperature were selected as significant predictors. The population prevalence of heterakidosis was 0.24 (0.19-0.29). Countries with continental and dry climates had a higher mean prevalence, whereas countries with tropical climates had a lower mean prevalence of heterakidosis. As more empirical data on heterakidosis prevalence become available, this model and predictions should be redefined and updated to capture a more representative association and increase the accuracy of the predictions. The results of this study can be used to attribute the economic losses of extensive backyard chickens, taking into account a holistic approach as promoted by the GBADs programme and therefore, to identify which diseases are more costly to backyard farmers. Furthermore, results can be also served as a proxy for the risk of histomoniasis in extensive backyard chickens.

Seroprevalence of infectious bursal disease in backyard chickens of selected districts of Buno Bedelle zone, Southwestern Ethiopia

BACKGROUND

Infectious bursal disease (IBD) is a viral infectious disease that affects young chicks. A cross-sectional study was conducted from October 2020 to June 2021 to determine seroprevalence and associated risk factors of IBD on backyard chickens of purposively selected three districts of Buno Bedelle Zone, Southwestern Ethiopia.

METHODS

The study was carried out via a collection of serum samples, questionnaire surveys, and a total of 768 serum samples were collected from randomly selected backyard chickens of the study areas and examined for the presence of IBD virus. These serum samples were processed by using an indirect enzyme-linked immunosorbent assay test procedure in laboratories. SPSS version 20 was used for data analysis and descriptive statics techniques were used.

RESULTS

Out of a total serum samples collected, 361 of them were found positive for the disease with an overall seroprevalence of 47%. Different seroprevalence rates of IBD with 55.9%, 43.3% and 41.2% were recorded in Didessa, Chora and Gechi districts, respectively. The result indicated that there was statistically significant difference (p < 0.05) of the disease among the three districts. Among the nine Peasant Associations (PAs) observed for seroprevalence of IBD, highest (62.9%) and lowest (34.20%) seroprevalence of the disease was recorded in Yembero and Shengela PAs, respectively. However, IBD was statistically significant in only Shengela PA of Chora district (p = 0.04, OR = 1.93 and 95% CI 1.04-3.58) and Seko PA of Gechi district (p = 0.05, OR = 1.79 and 95% CI 1.01-3.16). Even though sex, breed, age, source and management-based seroprevalence was observed in the present study, the result indicated that there was only statistical significant difference (p = 0.004, OR = 0.62 and 95% CI 0.45-0.86) seen in which higher seroprevalence of IBD was determined in exotic (50.3%) than in local (38.6%) chickens breeds of the study areas.

CONCLUSION

Generally, higher seroprevalence of IBD in the present study indicates a widely distribution of the disease and one of the potential threats for poultry production in the study areas. So, chicken vaccination and improved management system should be warranted in order to control the disease effectively.

Prevalence of intestinal parasites in humans and domestic animals in Jirel community, Dolakha, Nepal

Introduction

Gastrointestinal (GI) parasites are major health concerns in both humans and domestic animals. Livestock farming is one of the common livelihood practices in rural Nepal. The proximity at human and domestic animal interface increases the chances of dissemination of enteric parasites, especially those of zoonotic importance. This study was aimed at finding the parasite prevalence and risk factors in both humans and their domestic animals in Jirel community.

Materials and Methods

A field survey was conducted on the Jirel ethnic people and their domestic animals in Dolakha district, where a total of 152 fresh fecal samples from humans and domestic animals (cow, pigs, goats, chickens, ducks, and pigeons) were collected. The feces were examined by wet mounts and concentration techniques. A structured questionnaire survey was carried out among the local people and owners of the domestic animals to gather sociodemographic information, awareness, and hygienic practices in relation to parasite transmission.

Results

The enteric parasite prevalence was found to be highest in goats (80.0%;12/15), followed by pigs (55.55%;5/9), cows (45.45%;6/11), chickens (11.7%;4/34), and humans (1.41%;1/71), while the fecal samples of ducks and pigeons did not contain any parasites. The only parasite identified in humans was Ascaris lumbricoides. Similarly, three genera of GI parasites (Eimeria sp., Strongyloides sp, and Trichuris sp.) from goats, two genera each from cow (Eimeria sp. and Strongyloides sp.), pigs (Entamoeba sp. and A. suum), and chickens (Eimeria sp. and Ascaridia galli), were detected.

Conclusions

Based on the direct field observation, questionnaire survey and laboratory analysis, it is concluded that the Jirel community people are aware of health and hygiene; however, intervention measures are necessary to prevent parasitic infection in their domestic animals.

Prevalence of gastrointestinal helminth parasite infections in country chicken from Visakhapatnam district Andhra Pradesh India

Birds in a free environment carry huge risk of helminth parasite infections affecting the health of poultry and thereby indirectly leading to great economic loss. The present study aimed to evaluate the prevalence, intensity and species diversity of gastrointestinal helminth parasites (GIH) of country chicken (Gallus gallus domesticus) from local chicken markets of Visakhapatnam district, Andhra Pradesh. A total of 300 gastrointestinal tract (GIT) samples were examined from January to December 2021 and the collected parasites were separated, counted, identified and statistically analysed. The overall prevalence of infection was found to be 87% with an intensity of 139.29. The study showed high prevalence with mixed infections (66%), whereas the prevalence with individual groups i.e. cestodes, nematodes and trematodes was found to be 83.00%, 70.33%, and 0.67% respectively. Altogether 10 parasite species were identified viz. Raillietina echinobothrida being the most dominant with a prevalence of 72.67%, followed by Raillietina tetragona (62.00%), Heterakis gallinarum (59.33%), Ascaridia galli (45.33%), Davainea proglottina (43.00%), Amoebotaenia cuneata (42.67%), Raillietina cesticillus (38.33%), Hymenolepis sp. 1 (36.00%), Cotugnia spp. (29.67%) and the least was Hymenolepis sp. 2 (21.00%). In month-wise data, highest prevalence was recorded in July (100%), and the highest seasonal prevalence was recorded in summer (90%), followed by monsoon (87%) and winter (84%). No major significant difference in prevalence was noted between males (88.51%) and females (85.53%). Hosts with high body temperature and low GIT pH levels showed increased prevalence and parasite intensity.

Interactions between the helminth and intestinal microbiome in smallholder chicken farming systems

Helminth parasite infections are widespread in smallholder farming systems affecting farmers and livestock animals. There are pathogenic parasites that populate the gut of their host and coexist closely with the gut microbiota. The physical and immunological environment of the gut can be modified by parasites and microbiota creating a wide range of interactions. These interactions modify the development of infection, affects overall host health, and can modify the way a host interacts with its bacterial microbiota. In addition, where there is a high worm burden parasites will affect the health of the host and intestinal tract colonization. This review highlights key studies on the interaction between helminth parasites and the intestinal microbiome to understand the relationship between parasitic worm infections and gut microbiome health in chickens. Finally, the review discusses modulations, molecular changes, and the importance of helminth-microbiome interactions for the host.

Genetic Comparisons of Body Weight, Average Daily Gain, and Breast Circumference between Slow-Growing Thai Native Chickens (Pradu Hang dum) Raised On-Site Farm and On-Station

To ensure that any new technology developed within an experimental station is appropriate to the community’s needs and compatible with the existing systems, on-site farm research is an important component in examining the effectiveness of agricultural research. The present study examined the growth performance and genetics of Thai native chickens under conditions typically experienced by farmers on smallholder farms (on-site farms) compared with at an experimental unit (on-station). There were 1694 Thai native chickens (Pradu Hang dum) used in this experiment, and they were divided into 613 chickens for the on-station and 1081 chickens for the on-site farm experiments. The individual chicken data included the birth weight (BW0) and body weight at 4, 8, 12, and 16 weeks of age (BW4, BW8, BW12, and BW16, respectively), ADG from 0−4, 4−8, 8−12, 12−16 weeks of age (ADG0−4, ADG4−8, ADG8−12, ADG12−16, respectively), and breast circumference at 8, 12, and 16 weeks of age (BrC8, BrC12, BrC16, respectively). A multiple traits animal model and a selection index were used to estimate the variance components, genetic parameters, and breeding values of growth traits. The results showed that the body weight, average daily gain, and breast circumference at 8, 12, and 16 weeks of age of Thai native chickens raised on-station were higher than those raised on-site at the farm among mixed-sex and sex-segregated chickens, while the birth weight and body weight at four weeks of age (BW0 and BW4) and ADG from 0−4 weeks of age (ADG0−4) were not significantly different (p > 0.05). The heritability estimates of body weight, average daily gain, and breast circumference in the chickens raised at the on-site farm and on-station were moderate to high, with on-station values slightly higher than on-site farm values. The heritability estimates of body weight were 0.236 to 0.499 for the on-site farm, and 0.291 to 0.499 for on-station. For average daily gain, the heritability estimates were 0.274 to 0.283 for the on-site farm and 0.298 to 0.313 for on-station; meanwhile, and for breast circumference, the heritability estimates were 0.204 to 0.268 for the on-site farm and 0.278 to 0.296 for on-station. Both phenotypic and genetic correlations among and between growth traits were positive and ranged from low to high values. The top 20% of the estimated breeding values and selection indices in the on-site farm and on-station experiments showed that the body weight at eight weeks of age (BW8), ADG from 4−8 weeks of age (ADG4−8), and breast circumference at eight weeks of age (BrC8) should be used as selection criteria for Thai native chicken breeding programs. In conclusion, the genetic parameters and breeding values in on-station experiments showed that the breeding program by selection index for improving growth performance is valid. Therefore, to implement such a breeding program in an on-site farm, an intensive or semi-intensive farm system should be considered to minimize the effect of genotype-environment interaction.

Identification of The Main Intestinal Helminths of Local Breed Chickens (Gallus Gallus Domesticus Linnaeus, 1758) Reared in Traditional Mode in The Oran Region

In order to gain a better etiological and epidemiological knowledge of the parasitic diseases of local breed chickens reared in extensive (traditional) mode, a study was carried out in the Oran region during the periods from February 2020 to April 2020. Ten chickens were examined by the helminthologic autopsy method to identify parasitic helminths in the digestive tract. Four species of helminths have been identified: two species of nematodes: Ascaridia galli and Heterakis gallinarum and two species of cestodes: Raillietina cesticillus and Raillietina tetragona. Six chickens were carriers of the parasites, for an overall level of infestation of 60 % with an average infestation of 7 parasites per chicken. The rate of parasitism and infestation varied from species to species, Heterakis gallinarum being the most dominant species. The estimate of the infestation rate by each group shows a predominance of nematodes with 62 parasites (88.5 %) compared to cestodes (8 parasites) with a significantly higher difference (P <0.05). The results obtained show that chickens of the local Gallus gallus domesticus breed in the Oran region are heavily infested by parasites including Heterakis gallinarum, the predominant species.

Seroprevalence and Associated Risk Factors of Infectious Bursal Disease in Chickens Managed Under Intensive and Backyard Production Systems in Western Oromia, Ethiopia

Background

Infectious bursal disease (IBD) is a highly contagious viral disease challenging poultry industry throughout the world. It is also among the main obstacles in the different chicken production system in Ethiopia. This study was conducted with the aim of determining seroprevalence and associated risk factors of IBD in backyard and intensively managed chickens of the study area.

Methods

A cross-sectional study was conducted in selected districts of western Oromia on intensive and backyard production systems to investigate seroprevalence of IBD and associated risk factors from September 2020 to August 2021. A total of 384 chickens of either sex, 128 from each district, were included from three randomly selected peasant associations (PAs). In addition, 180 individual poultry keepers, of both sexes, and different educational backgrounds, were included for questionnaire survey (Supplementary Material). Data were analyzed using SPSS Version-20, and results were presented as percentages. The samples were processed by using (ProFLOKIBV, USA) indirect enzyme-linked immunosorbent assay (I-ELISA) kits.

Results

Out of 384 serum samples tested, 66.93% (n = 257) were found positive by indirect ELISA. The highest prevalence was recorded from Sasiga district Balo Bareda PA. Prevalence of IBD showed significant statistical association (p < 0.05) among owner education level, chicken rearing practice, origin and breed. Questionnaire survey results showed the majority of respondents lack sufficient knowledge about IBD and other chicken diseases. The practice of backyard chicken producers on vaccination and treatment of sick birds is limited.

Conclusion

In conclusion, IBD is a major factor hindering production and health of birds. Proper vaccination programs coordinated with awareness creation of chicken owners on how to isolate and treat sick birds should be implemented.

Prevalence and seasonal dynamics of gastrointestinal nematodes of domestic fowls (Gallus gallus domesticus) in Kashmir, India

Objective:

The current study was undertaken to evaluate the seasonal dependency and prevalence of gastrointestinal roundworms (nematodes) infecting domestic fowls (Gallus gallus domesticus) in Kashmir.

Materials and Methods:

From August 2017 through July 2019, the investigation was undertaken during each of the four seasons. We tested 400 guts obtained from varied places around the Kashmir valley for nematode infestation. The nematodes found within the digestive tract were collected and identified using a variety of identification keys under the microscope. Statistical Package for the Social Sciences was used to analyze the data (version 20). Chi-square (χ²) test was carried out to analyze the sample data.

Results:

196 hosts were infected with various nematodes, indicating an overall prevalence of 49% (196/400). The findings revealed that the prevalence of Ascaridia galli was 32.97% (61/185) in the first year and 35.34% (76/215) in the second year. Heterakis gallinarum had a prevalence rate of 20.80% (38/185) in the first year and 24.18% (52/215) in the second year, whereas Capillaria spp. had a prevalence rate of 10.81% (20/185) in the first year and 12.55% (27/215) in the second year. The overall prevalence of A. galli was determined to be 34.25% in both years (August 2017–July 2019), with a mean intensity of 4.86. Summer months had the highest parasitic load. Heterakis gallinarum had a prevalence rate of 22.5% and a mean intensity of 26.83. Summer was shown to have the most considerable parasitic burden. Capillaria spp. had an overall prevalence of 11.75% and a mean intensity of 4.59; autumn had the highest parasite load. The most abundant species was identified as A. galli. It was shown that there is a significant (p < 0.01) link between seasonality and helminth parasite prevalence.

Conclusion:

The study’s findings indicate that these gastrointestinal nematodes are ubiquitous throughout the year, but are particularly abundant in the summer and fall seasons among domestic poultry in the study area. This study on the prevalence of gastrointestinal nematodes in Gallus gallus domesticus demonstrates the seasonality of infection rates and also offers various methods and techniques for framing effective strategies for controlling these helminthes to maximize profit from backyard chicken farming.

Chicken Ascariasis and Heterakiasis: Prevalence and Associated Risk Factors, in Gondar City, Northwest Ethiopia

Introduction

Chicken nematodes are found all over the world. Ascaris and Heterakis are among the cosmopolitan chicken nematodes. In different parts of Ethiopia, these parasites have long been thought to be the leading cause of illness and loss of productivity. However, there has been little research on their burden in Gondar city; hence, this study was carried out to establish a realistic estimate of the prevalence of Ascariasis and Heterakiasis in chickens.

Methodology

A cross-sectional study was undertaken in Gondar city, North West Ethiopia, from November 2019 to May 2020 to evaluate the prevalence and different related risk factors of chicken Ascaris and Heterakis infections. A total of 384 hens were tested utilizing the faecal flotation technique, with 170 native and 214 alien varieties. During the collection of faecal samples, the breed, age, production system, and feces consistency of chickens were all taken into account.

Results

One hundred seventy-one (44.5%) of the total (384) investigated feces tested positive for at least one of these parasite illnesses. The parasite's prevalence was influenced by age, breed, and the type of production technique used. A higher infection rate was observed in the younger (68.9%) indigenous (67.1%) chickens reared under the extensive production system (46.9%).

Discussion and Conclusion

The prevalence of ascariasis and heterakiasis was nearly half percent in this study, even though the study was conducted in dry season, which is relatively unfavorable to parasites living in the environment and it specified only on the two common chicken ascaris nematodes. This study strongly suggested that Ascaris and Heterakis parasites were serious problems for chickens in Gondar city, and appropriate control strategies needed to be advised.

An overview of health challenges in alternative poultry production systems

Due to consumer demand and changing welfare standards on health, ecology, equity, and safety concepts, poultry production has changed markedly over the past 20 y. One of the greatest changes to poultry production standards is now offering poultry limited access to the outdoors in alternative and organic poultry production operations. Although operations allowing access to the outdoors are still only a small portion of commercial poultry production, it may impact the gastrointestinal (GIT) health of the bird in different ways than birds raised under conventional management systems. The present review describes current research results in alternative systems by identifying how different poultry production operations (diet, environmental disruptive factors, diseases) impact the ecology and health of the GIT. Various research efforts will be discussed that illustrate the nutritional value of free-range forages and how forages could be beneficial to animal health and production of both meat and eggs. The review also highlights the need for potential interventions to limit diseases without using antibiotics. These alternatives could enhance both economics and sustainability in organic and free-range poultry production.

Global and regional prevalence of helminth infection in chickens over time: a systematic review and meta-analysis

Gastrointestinal helminth parasites are a concern for the poultry industry worldwide as they can affect the health, welfare, and production performance. A systematic review of the prevalence over time in different countries may improve our understanding of gastrointestinal helminthiasis in chickens and subsequently lead to improved poultry health. The aim of this systematic review and meta-analysis was to provide an overview of the published information regarding the epidemiology and the diagnostic approaches of chicken helminth infection. Six databases were searched for studies, and a total of 2,985 articles published between 1942 and 2019 were identified and subsequently screened for eligibility using title or abstract and full text assessment, resulting in 191 publications to be used in the study. Postmortem diagnostics (73.8%) and the flotation technique (28.8%) were commonly used to detect helminth infections with a pooled prevalence of 79.4% ranging from 4 to 100%. More than 30 helminth species in chicken populations were identified including Ascaridia galli (35.9%), Heterakis gallinarum (28.5%), Capillaria spp. (5.90%), and Raillietina spp. (19.0%) being the most prevalent. The reported prevalence of helminth infection decreased over time in developing countries while it increased in the developed world. Chicken kept in backyard and free-range systems had a markedly higher pooled prevalence of helminth infection (82.6 and 84.8%, respectively) than those housed in cage production systems (63.6%). This may indicate the need for more rigorous control and prevention measures in free-range and backyard production systems using regular deworming coupled with access to early and accurate diagnosis allowing for early intervention.

The influence of hydro-meteorological conditions on the spread of chicken cestodiasis

Today one of the important problems in poultry farming and bird keeping both in homesteads and on farms is the spread of endoparasites, which cause a significant decrease in productivity and significant economic damage. Raillietinosis and daveniosis are natural focal tape helminthiases that parasitize in the small intestine of poultry. The research on chicken cestodiasis was carried out on poultry farms in the south of Odessa Region of Ukraine during 2017 and 2019. 4219 chickens of different age groups were examined, which used walking areas, with 1965 chickens – in 2017 and 2254 – in 2019. To assess the wet and dry periods with daily average temperatures above 10 °C, that is the period of active vegetation, the Selyaninov hydrothermal coefficient (SHC) was used (1937), according to which the spread of chicken cestodiasis was determined. In the south of Odessa Region, the moderate and severe period increased from four to seven months, at which the hydrothermal coefficient amounted to 0.4–0.8. The period of sufficient moisture at a hydrothermal coefficient of 1.0–1.5 decreased from three months of 2017 to two months of 2019 and the hydrothermal coefficient was not calculated for five and three months, respectively. In 2017, the hatching of cestode eggs with bird manure was recorded for nine months: from March (10.1%) to November (5.8%) with high rates in June (27.2%) and September (37.1%), while in 2019, cestode eggs were recorded in February (12.7%) and up to December (2.4%), that is, for 11 months, with the highest rates in May (41.8%) and September (43.9%). The species composition of chicken cestodes is represented by four species: Raillietina echinobothrida (74.2%), which dominates due to a longer low hydrothermal coefficient, as well as R. tetragona (9.8%), R. cesticillus (10.8%) and Davainea proglottina (5.2%). The invasion of ants with cysticercoid R. echinobothrida in 2017 amounted to 19.6%, and in 2019 – 25.9% with an intensity of 1 to 4 specimens.

Morphological and Molecular Characteristics of the Gastro-Intestinal Nematode Parasite Ascaridia columbae Infecting the Domestic Pigeon Columba livia domestica in Saudi Arabia

BACKGROUND

Parasitism is a complex problem that is often ignored in companion animals, including birds, unless it develops into a severe clinical disorder. The present study was, therefore, aimed to investigate the presence of the gastrointestinal nematode infecting the domestic pigeon and provide a complete morphological description and clarify its taxonomic position through phylogenetic analysis of the ITS1-5.8s-ITS2 rDNA gene region.

MATERIALS AND METHODS

During the current study, a total of twenty-six domestic pigeons, Columba livia domestica, were collected and internal organs examined for helminth detection. Using light and scanning electron microscopy, the recovered parasite species are studied. In addition, the selected gene region was obtained and sequenced using appropriate primers that aid in the formation of the phylogenetic dendrogram for the recovered parasite species with others retrieved from GenBank.

RESULTS

Morphological examination showed that this nematode parasite belongs to the Ascaridiidae family within the genus Ascaridia. The material was assigned to the previously described Ascaridia columbae by providing all the characteristic features as the presence of a mouth opening surrounded by three tri-lobed lips; each lip has two triangular teeth with a spoon-like structure, cephalic papillae and amphidal pores on lips surface, presence of lateral cuticular alae and pre-cloacal sucker, 10 pairs of caudal papillae, and two equal spicules in male worms. The morphological investigations of this species were supplemented by molecular analysis of ITS1-5.8s-ITS2 rDNA gene region. The data showed that the present A. coulmbae is deeply embedded in the Ascaridia genus with a 74-99% sequence similarity to other species in the Chromadorea class. Ascaridiidae appears as monophyly and represented as a sister group to Heterakidae. The ascaridiid species examined belong to the Ascaridia genus and displaced a close relationship with the previously described A. coulmbae (gb| KF147909.1, gb| AJ001509.1, gb| KC905082.1, gb| JQ995321.1, gb| JX624729.1) as putative sister taxa.

CONCLUSION

The present study revealed that the species Ascaridia is the first account of this genus as an endoparasite from the domestic pigeon inhabiting Saudi Arabia. Therefore, the combination of morphological and molecular studies helps to identify this species correctly and identified as Ascaridia columbae.

Molecular characterization of Raillietina isolates from the gastrointestinal tract of free range chickens (Gallus Gallus domesticus) from the southern region of Zimbabwe using the 18S rDNA gene

Parasitic diseases are among the major constraints of poultry production. The common internal parasitic infections occurring in poultry include cestodes and other gastrointestinal helminths. The aim of this study was to characterize Raillietina spp. from the gastrointestinal tract of free-range chickens using 18S rDNA genes. This was achieved through the DNA extraction from tapeworms isolated from the gastrointestinal tract of routine slaughtered free-range chickens using 18S and amplifying the partial 18S rDNA genes using PCR. A total of 34 intestine samples were collected from 9 different areas in Matabeleland region and tapeworms were isolated for microscopic examination and morphological characterization. All 34 chickens examined had tapeworms and morphological characterization confirmed those used in the study as belonging to the Raillietina group. DNA extraction was then successfully carried out for 9 cestode isolates followed by the PCR amplification of the 18S genes. The products were sequenced and 4 of the 9 isolates were positively identified using BLAST as Raillietina tunetensis and the other 5 were only identified as Raillietina spp. These sequences were then aligned with other known sequences of Raillietina isolates from GenBank and a phylogenetic tree was constructed using the neighbor-joining method and distance computed using the maximum composite method. The phylogenetic tree showed that three of the unidentified Raillietina species are in the neighboring position with Raillietina sonini whilst the other two are in the neighboring position with Raillietina tetragona. This is the first record of R. tunetensis in Gallus Gallus domesticus from Zimbabwe. This clustering on the phylogenetic tree however, did not differentiate samples according to geographical location showing that this tool can be used to infer phylogenetic data for speciation.

Haemato-biochemical changes and prevalence of parasitic infections of indigenous chicken sold in markets of Kiambu County, Kenya

This study aimed at determining parasitic prevalence and probable haemato-biochemical changes that may occur from parasitic infections in marketed indigenous chickens in Kiambu County, Kenya. Thirty adult chickens were purchased and examined for ectoparasites, haemoparasites and haemato-biochemical changes. Post mortem was conducted to recover gastro-intestinal parasites and fecal samples taken for egg/oocyst counts. Forty-seven percent (14/30) of chickens examined were in poor body condition, 43% (13/30) in fair and 10% (3/30) in good body condition. Ectoparasites infection prevalence was 66.7% (20/30). Four haemoparasites were isolated. Overall helminths prevalence was 86.6% (26/30), nematodes at 76.7% (23/30) and cestodes at 40% (12/30). After processing fecal samples, 30% (9/30) were positive for helminth eggs and 30% (9/30) had coccidial oocysts. Relative to normal values, total erythrocyte count was low and total leucocyte count with band cells high. Mean haematocrit and heterophil values were high (p=0.0005; p=0.0061). Mean lymphocyte count was low (p=0.0128) in chickens with ectoparasitic infestation. Eosinophils increased significantly (p=0.0363) although mean erythrocytes counts decreased (p=0.0176), in chickens with gastrointestinal parasites. Creatine phosphokinase and blood glucose levels were high, serum protein and albumin levels were low. Blood glucose level decreased significantly (p=0.0239) and total plasma protein increased (p=0.045) in chickens with Haemoproteus spp. infection. The study showed, ecto- and endo-parasites are prevalent and may contribute to alteration of haemato-biochemical parameters of sub-clinically infected marketed indigenous chickens. These results are expected to contribute towards and encourage usage of clinico-pathological parameter testing as a measure of poultry health status for enhanced poultry disease diagnoses.

Rearing system causes changes of behavior, microbiome, and gene expression of chickens

It has been long demonstrated that cage rearing (CR) deprives the animal of the possibility to express natural behaviors and results in stress. However, the effect of the rearing system on gene expression and the molecular levels of the gut microbiome are unknown. 10-wk-old Beijing You chickens were studied in parallel CR and free-range (FR) systems for 30 wk, to investigate the effect of rearing systems on behavior, microbiota composition, and gene expression. From week 40, a match-mismatch design was conducted for 5 wk. The results indicated that CR deprives the animals of natural behaviors, evidenced by sham dust-bathing behavior. A decreased alpha diversity of gut microbiome composition of CR chickens was seen in FR compared to CR-FR chickens (P < 0.001), and the alpha diversity of gut microbiome composition of FR-CR was decreased as compared to FR chickens (P = 0.045). The heat map and beta-diversity analysis showed that the cluster of gut microbial compositions were similar between the mismatch groups (FR-CR and CR-FR), while those of CR showed the lowest diversity from the 4 groups. The relative abundance of gut microbes at genera and species levels was different between comparisons (P < 0.05). Moreover, the CR (both CR and FR-CR) triggered the downregulation of most Kyoto encyclopedia of genes and genomes pathways, while it was upregulated in 2 genetic information processing pathways, compared to FR hens regardless of long or short term. In conclusion, CR deprived chickens of their normal behavior and resulted in changes in the microbiome diversity and pathways and gene expression of chickens.

Gastrointestinal Helminth Parasites of Chicken under Different Management System in Mekelle Town, Tigray Region, Ethiopia

The poultry industry is an infant but fast growing sector in Ethiopia. However, it is largely dependent on local chicken managed under backyard production system. The sector is facing different challenges, mainly emanated from prevalence of infectious diseases such as helminth parasite species. Hence, this study came up with an aim to determine the infection rate and identify helminth parasite species in chickens managed under different production systems, in Mekelle, Ethiopia. A cross-sectional study design was employed, from November 2015 to March 2016. Postmortem (N=138) and fecal (N=410) samples of chicken were considered for necropsy and coproscopic examination to see both adult and eggs of helminth parasites, respectively. Similar gastrointestinal helminth parasites infection rate of chicken was obtained from both examination approaches (necropsy, 90.60%; and coproscopy, 90.97%). The study attested high prevalence (87.7%) of mixed infection with helminth parasites of chicken. Heterakis gallinarum (72.5%) and Ascaridia galli (68.8%) were found as the most dominant species (necropsy). During coproscopic examination cestode (89%) infections showed a relatively higher prevalence than nematodes (84.4%), although no difference was observed during that of necropsy examination results. Chickens of local breed from backyard production system had shown more likelihood of getting helminth infection when compared with their corresponding relatives (coproscopy). However, the variation was not statistically significant during that of necropsy finding. Therefore, the higher prevalence of parasitism and mixed infection observed in the study area would warrant for an urgent intervention with regular deworming scheme, and strict attention should be given towards hygienic measures and other health related management activities.

Gastrointestinal helminths of backyard chickens in selected areas of West Shoa Zone Central, Ethiopia

Gastrointestinal parasites of chickens are prevalent in many parts of the world including Ethiopia. This study was conducted with backyard chickens in Ambo, Holeta and, Dire Inchini in the West Shoa zone with the objectives of estimating the prevalence of gastrointestinal helminth infections, identifying the species present and determining associated risk factors. A cross-sectional study was conducted using 252 chickens purchased from local markets. Chickens were killed humanely and gastrointestinal tracts were examined for adult helminths. Identification of the helminths was performed using morphology and microscopy. The overall prevalence of helminth parasites in chickens was 92.1% (232/252) [95% confidence interval (CI): 88.0% - 95.1%]. 80.2% (204/252) [95% CI: 75.3% - 86.9%] and 77.8% (196/252) [95% CI: 72.1% - 82.8%] of chickens were infected with diverse nematode and cestode species, respectively. Parasitological examination revealed the presence of three nematode and five cestode species. Ascaridia galli (69.8%) and Heterakis gallinarum (13.5%) were the dominant nematode species and Railletina tetragona (54.0%) and Railletina echinobothrida (46.8%) were the most prevalent species of cestodes identified. A significant difference (p < .05) was observed between the prevalence of nematode parasites and sex, age, and origin of the chicken. Similarly, sex and origin of the chickens were significantly different with the prevalence of cestode infections. Higher prevalence was observed in male versus female chickens, in young versus adult chickens and in chickens from Holeta and Direinchin compared to Ambo. In contrast, weight, health status, diarrhea status, and age (for cestodes) were not significantly associated with nematode and cestode infection. In conclusion, the present study detected a high prevalence of diverse types of gastrointestinal helminths in backyard chickens, which could result in poor health and reduce productivity. Therefore, the present study strongly suggests appropriate and strategic control of helminthiasis to improve the health and output of backyard chickens in the study areas.

Ascaridia galli isolates with ITS1-5.8rRNA-ITS2 fragment homologous to Ascaridia columbae

Ascaridia (A.) galli is one of the most commonly occurring nematodes in poultry worldwide, often in hens and broiler chickens. The infection with Ascaridia galli in free-range chickens was even 70%. There is not much information about A. galli genetic features. The present study was conducted to assess the genetic diversity of A. galli isolated from hens in Poland by analyzing the nucleotide sequence of the region ITS1-5.8rRNA-ITS2 and to define its homology within the family Ascaridiidae. Adult A. galli were collected from the intestines of naturally infected hens from two flocks of free-run laying hens from the Wielkopolska region in Poland. From all parasites an identical ITS1-5.8rRNA-ITS2 sequence was obtained, which was homologous in 99% with A. columbae (JQ995321.1) sequence. The high homology sequences of A. galli (KX683286) from Poland and A. columbae (JQ995321.1) isolate from the USA, support the observations of other authors suggesting that A. galli and A. columbae might be closely related. It is the first whole ITS1-5.8rRNA-ITS2 of A. galli in the GenBank database, so there is not enough data for detailed phylogenetic analysis of A. galli. Detailed genetic analysis is necessary to get better insight into the birds' Ascaridia species.

Prevalence and burden of gastrointestinal helminthes among grey-breasted helmet guinea fowls (Numida meleagris galeata) encountered in Gombe state, Nigeria

This cross sectional survey was conducted from July to December 2015 in order to investigate the burden of gastrointestinal helminthes among guinea fowls in Gombe, Northeastern Nigeria. A total of six hundred fowls (viscera) were purchased from six randomly selected slaughter slabs. Out of the 600 birds examined, 479 (79.83%; 95% CI: 76.4, 82.9) were found harbouring one or more gastrointestinal helminthes. Of this, 238 birds (39.7%; 35.8, 43.6) were infected by nematode species and 392 birds (65.3%; 61.4, 69.0) by cestode species. A total of nine nematodes and seven cestodes species were recovered from these birds. There was no any trematode observed among the studied birds. The prevalences of the nematodes identified in descending order were: Ascaridia galli 56.7% (52.7, 60.6); Ascaridia numidae 38.0% (34.2, 42.0); Heterakis gallinarum 17.2% (14.4, 20.4); Heterakis meleagridis 8.3% (6.4, 10.8); Strongyloides avium 3.5% (2.3, 5.3); Subulura brumpti 3.2% (2.0, 5.0); Gongylonema ingluvicola 2.2% (1.3, 3.7) and both Dispharynx spiralis and Tetrameres numidae had 0.7% (0.3, 1.7). While for cestodes: Raillietina tetragona 72.8% (69.1, 76.2); Raillietina echinobothrida 67.3% (63.5, 71.0); Raillietina cesticillus 50% (46.0, 54.0); Raillietina magninumida 25.7% (22.3, 29.3); Hymenolopsis cantaniana 17.3% (14.5, 20.6); Davainea nana 4.2% (2.8, 6.1) and the lowest was observed in Choanotaenia infundibulum with 2% (1.2, 3.5). Infection rates did not differ significantly based on sex (P > 0.05). However, the occurrence of mixed infection as compared with single infection was statistically significant in both cestodes and nematodes (P < 0.001). The results obtained indicated high prevalence of gastrointestinal helminthes among guinea fowls. These birds may serve as important source of helminthes to other commercial birds in the study area.

Seasonal prevalence of gastrointestinal parasites in desi fowl (Gallus gallus domesticus) in and around Gannavaram, Andhra Pradesh

A study was carried out to know the prevalence of gastrointestinal parasites in desi fowl in and nearby villages of Gannavaram, Andhra Pradesh for a period of 1 year. Screening of 492 samples comprising faecal samples and gastrointestinal tracts from freshly slaughtered desi birds at local poultry shops and samples from post mortem examinations at NTR College of Veterinary Science, Gannavaram revealed 63.21 % of gastrointestinal parasites. Faecal samples were examined by floatation technique using salt solution and samples positive for coccidian oocysts were sporulated in 2.5 % potassium dichromate solution for species identification. Adult worms were identified after routine processing and mounting. The species identified includes Davainea proglottina, Raillietina cesticillus and Raillietina echinobothrida in cestodes (32.47 %), Ascaridia galli, Capillaria annulata, Heterakis gallinarum in nematodes (39.87 %), Eimeria tenella, Eimeria acervulina and Eimeria necatrix in Eimeria spp. (39.87 %). Ascaridia galli and R. cesticillus and A. galli and Eimeria spp. were common in mixed infection (12.86 %). Ascaridia galli was the more prevalent species. No trematode parasite was identified during the study period. Significant (p = 0.001) relationship between the seasonality and prevalence of gastrointestinal parasites was observed (χ2 = 17.46, df = 2). Data revealed high prevalence in rainy season (43.41 %) followed by summer (38.91 %) and winter (17.68 %) seasons for all parasites except for A. galli and C. annulata infections which were higher in summer season. Results indicated high prevalence of gastrointestinal parasites in desi fowl in study area emphasizing the need of improved management practices of backyard poultry.

Morphological characterization of nematodes of the genera Capillaria, Acuaria, Amidostomum, Streptocara, Heterakis, and Ascaridia isolated from intestine and gizzard of domestic birds from different regions of the temperate Kashmir valley

During a random survey of parasitisation of poultry birds of Kashmir, conducted for 3 years more than 300 poultry birds were randomly collected from different parts of the Kashmir valley and were examined for the helminth parasites. The most dominant group of parasites which was parasitizing the poultry birds was found to be the Cestode, whose prevalence in the infected birds was 76.9 %. Nematodes were found to be the second dominant group of parasites after cestodes with the prevalence of 70 %. Among the different species of nematodes Heterakis gallinae were found infecting almost all the birds autopsied. The highest intensity of H. gallinae might be because of the fact that it requires cockroaches, beetles and grasshoppers as intermediate hosts in addition of having a direct life cycle. Nematodes which were recovered from the intestine and gizzard of the birds belong to the genera Capillaria, Acuaria, Amidostomum, Streptocara, Heterakis, and Ascaridia.

Occurrence and HAT-RAPD analysis of gastrointestinal helminths in domestic chickens (Gallus gallus domesticus) in Phayao province, northern Thailand

The present study determined the prevalence and distribution of gastrointestinal helminths in domestic chickens (Gallus gallus domesticus) between November 2012 and August 2013. One hundred and twenty domestic chickens were purchased from villages in four districts of Phayao province; Mae Chai, Dok Khamtai, Chun and Chiang Kham. Morphological differences were used to identify the helminth species, and HAT-RAPD technique was used to differentiate among closely related species. The results revealed that the total prevalence of infection was 99.2%. Cestode and nematode infections showed the highest prevalence in rainy season, while trematode infections were low and only found in hot season. The species and their prevalence were: Ascaridia galli (50.8%), Heterakis gallinarum (86.7%), Prosthogonimus macrorchis (1.7%), Echinostoma revolutum (0.8%), Raillietina echinobothrida (48.3%), Raillietina tetragona (57.5%), Raillietina cesticillus (12.5%), Raillietina sp. (35.8%), Cotugnia chiangmaii (14.2%) and Cotugnia sp. (32.5%). The prevalence of helminth infections did not differ significantly between male and female chickens. HAT-RAPD analysis, the specific fragment of 400 and 250 bp indicated that Raillietina sp. and Cotugnia sp. found, respectively, differ from other closely related species. This study has confirmed that HAT-RAPD technique can be used to differentiate among related species combined with morphological observations.

Spatio-temporal factors influencing the occurrence of Syngamus trachea within release pens in the South West of England

Syngamus trachea is a pathogenic tracheal nematode that causes syngamiasis in wild and game birds, especially when birds are managed at high densities. Despite its pathogenic nature, very little is known about its epidemiology and relationship with ambient temperature and humidity. The spatial and temporal modelling of disease was undertaken on two pheasant estates within the South West of England from April 2014 to August 2014. Significant differences between the mean numbers of eggs per gram of soil were identified between pens at both site 1 and site 2 but did not differ significantly between sites. Egg abundance was significantly associated with soil moisture content, with greater egg survival between years in pens with higher average volumetric soil moisture content. Previous years stocking density and pen age were also associated with greater egg survival between years with more eggs being recovered in pens with greater stocking densities, and pens that had been sited longer. The greatest model to explain the variation in the numbers of eggs per gram of soil per pen was a combination of soil moisture content, stocking density and pen age. Larval recovery differed significantly between sites. Larval abundance was significantly and positively associated with temperature and relative humidity at site 1. Similarly, temperature and humidity were also positively and significantly associated with larval abundance at site 2. Rainfall did not influence larval recovery at either site 1 or site 2. The model with the greatest ability to explain larval abundance at both sites, was a combination of temperature, humidity and rainfall. Infection status (positive faecal egg counts) was significantly and positively associated with larval abundance at both sites, but rainfall was only positively associated at site 1. Temperature and humidity were positively associated with infection status at site 2, but not at site 1. The present study highlights the influence of climatic variables on both egg survival and larval abundance, and could therefore be used to develop more targeted treatment strategies around periods of higher disease risk. The frequent use of release pens is a clear factor in the epidemiology of syngamiasis, and it is recommended that pens be rested and/or rotated in order to reduce infection pressure in subsequent flocks.

Prevalence of the gastro-intestinal parasites of domestic chicken Gallus domesticus Linnaeus, 1758 in Tunisia according to the agro-ecological zones

Helminthosis is a very important disease affecting the poultry industry, especially the traditionally reared free ranging chickens. In Tunisia, the poultry production is considered as the most important source of protein in as much as chickens provide 53 % of animal protein production. The traditionally reared poultry farming system exposes chickens to many types of parasites, however, very little work has been done to establish the extend of helminth infection in Tunisia. The aim of this work is to investigate various aspects of helminth infections. A significant difference (p < 0.01) was found between the prevalence rates of helminth parasites in the different agro-ecological zones. The highest prevalence was observed in lowland areas of northern Tunisia (Siliana district). This suggests that agro-ecology has a major influence on the distribution of helminth parasites. Recovered nematodes included Heterakis spp. (100 %), Ascaridia galli (53.33 %) and Acuaria hamulosa (37 %). The principal cestode species encountered were Hymenolepis spp. (73.33 %) and Raillietina spp. (33.33 %).

Biochemical and molecular characterization of the tegument protein RT10 from Raillietina tetragona

Tegument antigens of tapeworm play an important role in modulation of host response and parasite survival. Characterizing appropriate antigens for parasite infection diagnosis and vaccination is rational and could have both economic and epidemiological significance in poultry industry. In the present study, a major protoscolex homologue (named RT10) of Echinococcus and Taenia spp. was amplified from Raillietina tetragona cestode. The RT10 cDNA was 1,877 bp long containing an open reading frame of 1,683 bp nucleotides, which encoded a deduced protein of 560 amino acids with an isoelectric point of 6.33. Secondary structure analysis demonstrated that RT10 was both hydrophilic and antigenic, and possessed N-terminal FERM domain and C-terminal ERM domain, respectively. With the same structural properties of previously reported antigens from Echinococcus and Taenia spp., RT10 tegument antigen had a more than 82% similarity in nucleotide level with initially reported antigens from Echinococcus and Taenia spp., and a more than 83% similarity in protein level, with the highest similarity of 85.2% to Taenia antigen H17g. In addition, phylogenetic analysis illustrated a high consistency between different genus antigens and evolutionary branching. Although the detailed function of RT10 is still unknown, the high sequence conservation and structural similarity to formerly identified tegument antigens from Echinococcus and Taenia spp. suggested that RT10 may play a similar role as the previous reported antigens between cestode and host. It is significant to clarify the antigenic and serodiagnostic characteristics in the subsequent work.

Proteomic analysis of Ascaridia galli. Identification of immunoreactive proteins in naturally and experimentally infected hens

Ascaridia galli, intestinal parasite of domestic fowl, is responsible of economic losses in avian exploitations. However, molecular mechanisms that govern avian ascaridiasis remain largely unknown. The aim of the present work was to identify proteins of A. galli recognized by the immune system of naturally and experimentally infected hens, using two-dimensional electrophoresis (2-DE) and mass spectrometry (MS). Sixteen immunoreactive proteins of A. galli were identified. These proteins are mainly related to different metabolic processes, cell motility and binding activities. The timing evolution of this recognition pattern was studied using serum samples from experimentally infected hens, allowing us to observe an early recognition of many of these antigens. Many of them were isoforms from lipid and plasminogen-binding proteins. Moreover, plasminogen-binding activity has been related in other parasites with the facilitation of intra-organic migration, which represents an important fact in avian ascaridiasis. This work represents the first proteomic study of A. galli and could contribute to explain some aspects of parasite/host relationships of avian ascaridiasis.

Gastrointestinal helminths are highly prevalent in scavenging chickens of selected districts of Eastern Shewa zone, Ethiopia

A cross-sectional survey on gastrointestinal helminths was conducted on 124 chickens raised under traditional management system in two selected districts namely Ada'a and Adamitulu of Eastern Shewa zone, Ethiopia. Of these chickens, 111 (89.5%) were found to harbor one of the five different helminth parasites and 13 (10.48%) were free of helminths parasites. The study also found that 103 (83.0%) and 72 (58.0%) of the examined chickens were invariably infected by diverse species of cestodes and nematodes species, respectively. There was a statistically significant difference (p < 0.05) in the prevalence between cestodes and nematodes of helminths parasites within the same district. The major cestode species recovered form chickens were Raillietina echinobothrida 79 (63.7%), Raillietina tetragona 70 (56.5%), Raillietina cesticillus 50 (40.3%) and Choanotaenia infundibulum 17 (13.7%), Davainea proglottina 10 (8.1%), Hymenolepis contaniana 22 (17.7%) and Hymenolepis carioca 7 (17.7%). The major nematode species encountered were Heterakis gallinarum 47 (37.9%), Ascaridia galli 40 (32.0%), Gongylonema ingluvicola 32 (25.8%), Dispharynx nasuta 5 (4.0%), Heterakis isolonche 11 (8.9%), Allodapa suctoria 9 (7.3%), Capillaria anatis 4 (3.2%) and Heterakis dispar 8 (6.5%). The study also tried to see the prevalence of these parasites in relation with age and sex however, it has no significant difference (p > 0.05) with those risk factors. On the other hand district significantly affect the prevalence of some parasites (p < 0.05). This study strongly suggested that helminthosis is a very serious problem of backyard chickens in eastern Shewa zone of Oromia and appropriate control strategies need to be devised.

Prevalence of parasites of the local scavenging chickens in a selected semi-arid zone of Eastern Kenya

A study to identify and estimate the prevalence of parasites of local chickens in a semi arid area of Kenya was conducted between March 2005 and August 2006. Three hundred and sixty (360) local chickens purchased from Yathui division of Machakos were examined. Of those, 93.3% had helminths. Nematodes were recovered in 268 (74.4%) chickens whereas 245 (68.1%) had cestodes. Tetrameres americana (37.7%), Ascaridia galli (33.3%) and Heterakis gallinarum (22.8%) were the most important nematode species identified. Raillietina echinobothrida (33.3%) and Davainea proglottina (19.4%) were the two most important cestode species identified. Two coccidia species, namely Eimeria necatrix (6.7%) and E. tenella (16.7%) were isolated and identified as per location in the digestive system. Important ectoparasites identified included Echidnophaga gallinacea (76.7%), Menacanthus stramineus (79.4%) and Dermanyssus gallinae (60.0%). Endo-parasites (helminths and coccidia) occurred in significantly (p<0.05) higher frequencies during the wet season than during the dry season. On the contrary, ecto-parasites were significantly (p<0.05) more fequent during the dry season. Male chickens generally exhibited increased odds for the occurrence of parasites than female birds. Further investigations are required to establish a plausible explanation for this. Overall, parasitism was a big constraint to chicken productivity in the study area. Urgent integrated parasite control approaches should be initiated to address parasitism in chickens in the Yathui cluster.

Local chicken production system in Malawi: household flock structure, dynamics, management and health

Household flocks of scavenging chickens were monitored from August 2002 to August 2003 in 27 villages in Lilongwe, Malawi. The objective was to evaluate the local chicken production system by investigating flock structure, utilization, management and constraints. Farmers and researchers jointly obtained data on household flocks. Mean flock size was 12.9, with a range of 1-61 chickens. The flock dynamics of chickens over 8 weeks old constituted 91% migrating out of flocks and 9% into the flocks. Primary functions based on flock dynamics were, in order of importance, household consumption, participation in socio-cultural ceremonies, selling, exchanging breeding stock and gifts. Of the flock exits, 43.9% were due to losses from diseases, predation and theft. Most flocks (85%) were housed in human dwelling units. Scavenging was the main source of feed. The majority (77.6%) of farmers supplemented their chickens erratically with energy-rich feeds, mostly maize bran. Most supplementation took place during the cold-dry season. Village chicken production offers diverse functional outputs but faces animal health (diseases, parasites, predation) and management (feeding) constraints, which require an integrated intervention approach at community and household level.

Prevalence and distribution of gastrointestinal helminths and their effects on weight gain in free-range chickens in Central Zambia

Examination of helminths from gastrointestinal tracts of 125 free-range chickens in Zambia revealed a 95.2% prevalence rate. The species and their prevalences were: Allodapa suctoria (85.6%), Tetrameres americana (80.8%), Ascaridia galli (28.8%), Gonglonema ingluvicola (50.4%), Raillietina spp. (81.6%) and Heterakis gallinarum (32.8%). No trematodes or Syngamus trachea were found. Mixed infections accounted for 88.2% as compared to 7.2% of single infections. Effects of helminthoses on weight gain were investigated in 100 growing chickens randomly assigned to treatment (levamisole) and untreated control groups. There was a significant mean (+/- SEM) weight gain (grams) of 812.8 +/- 51.4 in the treatment group and 623 +/- 57.4 in the control group (p < 0.01). The mean (+/- SEM) worm burdens from the control group and the treatment group were 96.3 +/- 5.61 and 22.05 +/- 2.61, respectively. These results confirm the higher risk of helminth infections in free-range systems and may explain the deleterious effects in chickens.

Macrogeographic population structure in a parasitic nematode with avian hosts

Much remains to be discovered about the population genetic structure of parasites, despite the importance of such knowledge to understanding the processes involved in the spread of drug resistance through populations. Here we present a study of population genetic diversity in Trichostrongylus tenuis, an avian parasitic nematode infecting both poultry and game birds, where anthelmintic use is common. We examined diversity of nicotinamide dehydrogenase subunit 4 (nad4) mtDNA sequences within and between seven locations: five in the UK (red grouse hosts), one in Iceland (domestic goose) and one in Norway (willow grouse). Within-UK comparisons showed high nucleotide diversity (pi=0.015, n=23) but no structure between locations (Phi(ST)=0.022, P=0.27), with over 97% of variation distributed within-hosts. The highest diversity was found in Iceland (pi=0.043, n=4), and the lowest in Norway (pi=0.003, n=4). Differentiation between countries was considerable (Phi(CT)=0.44, P<0.05), in spite of the potential mixing effects of gene flow via migrating wild hosts and the poultry trade. However, significant pairwise F(ST) values were found only between Norway and the other locations. Phylogenetic analysis provided statistical support for a separate clade for Norwegian samples only, with unresolved diversity leading to a star-shaped relationship between Icelandic and UK haplotypes. These results suggest that Norwegian T. tenuis are isolated, but that there is some connectivity between UK and Icelandic populations. Although anthelmintic resistance has not yet been reported for T. tenuis, the population structure is such that emerging resistance has the potential to spread by gene flow over a large geographic scale.

Gastrointestinal helminths in indigenous and exotic chickens in Vietnam: association of the intensity of infection with the Major Histocompatibility Complex

This study compared the prevalence and intensity of infections of helminths in 2 chicken breeds in Vietnam, the indigenous Ri and the exotic Luong Phuong. Also, possible correlations with the Major Histocompatibility Complex (MHC) were tested. The most prevalent helminths were Ascaridia galli, Heterakis beramporia, Tetrameres mothedai, Capillaria obsignata, Raillietina echinobothrida and Raillietina tetragona. Differences in prevalence and intensity of infection were found between the 2 breeds. Comparing the 2 groups of adult birds, Ri chickens were observed to have higher prevalence and infection intensities of several species of helminths, as well as a higher mean number of helminth species. In contrast, A. galli and C. obsignata were shown to be more prevalent in Luong Phuong chickens. Furthermore, an age-dependent difference was indicated in the group of Ri chickens in which the prevalence and the intensity of infection was higher for the adult than the young chickens for most helminths. The most notable exception was the significantly lower prevalence and intensities of A. galli in the group of adult chickens. In contrast, the prevalence and intensity were very similar in both age groups of Luong Phuong chickens. Using a genetic marker located in the MHC, a statistically significant correlation between several MHC haplotypes and the infection intensity of different helminth species was inferred. This is the first report of an association of MHC haplotype with the intensity of parasite infections in chickens.

The impact of natural helminth infections and supplementary protein on growth performance of free-range chickens on smallholder farms in El Sauce, Nicaragua

Three on-farm studies were conducted in Nicaragua during three consecutive years (1999-2001) to assess the impact of natural helminth infections on growth performance of free-range chickens aged 3-4 months. On all participating farms, half of the chickens were treated regularly with anthelmintics (Trifen avicola - a combined formulation of piperazine, phenothiazine and dichlorophen - or albendazole) to express the growth potential of non-infected birds, whereas the other half served as non-treated controls. In 1999, treated chickens had a 39% higher weight gain compared to the control group 6 weeks after the first treatment on 15 farms. In 2000 and 2001, treated chickens had similar weight gain as the control group 10 weeks after the first treatment on 7 farms and 12 farms, respectively. The main reason for the very-different weight gain figures seems to be the weather conditions. In 1999, the study site experienced a rainy season with precipitation far above average, whereas in 2000 and 2001 the rainy seasons had precipitations far below average. Based on these findings, routine use of anthelmintics in the study area would only be recommended in wet years when production losses due to helminth infections seem to be pronounced. In 2001, the study set-up included an assessment of the effect of protein supplementation (soybean) on growth on six farms. Supplemented chickens (treated and non-treated with anthelmintics) had 17% higher weight gain than non-supplemented. Protein supplementation affected neither worm burdens nor faecal egg counts for any of the studied helminths. The post-mortem examinations showed that Trifen reduced burdens of Ascaridia galli, Heterakis gallinarum, and cestodes (efficacies of 100, 100 and 67%, respectively). Albendazole reduced burdens of H. gallinarum (efficacy of 100%). Efficacies against other helminths were difficult to assess due to low worm burdens. Chickens treated with albendazole had lower Ascaridia and Heterakis faecal egg counts than non-treated chickens.

A Coprological and Serological Survey for the Prevalence of Ascaridia spp. in Laying Hens

Ascaridia galli is a common nematode found in the intestine of domesticated chickens. The objectives of the study were to conduct a coprological and serological survey on the prevalence of ascaridiosis in laying hens of commercial farms. The farms recently adopted a breeding programme, where the hens have access to outdoor pens. Different amounts of Ascaridia eggs were detected in five of seven studied farms, while the other two farms were found to be free from the parasite. Serological tests revealed a seroprevalence of 21.8% (range 7.6-95%). No positive serum samples were detected in the same farms with previous negative coprological analysis. Western blot analyses confirmed the results obtained by the enzyme-linked immunosorbent assay (ELISA) test. In four experimentally infected hens, a progressive increase of the IgG antibody levels was observed, surpassing the cut-off point established for ELISA test 6 weeks post-infection. Serological tests are able to detect the infection before the eggs of the parasite appear in the faeces of infected hens, providing a useful tool to detect infections with Ascaridia spp. in avian farms.

An experimental infection model for Tetrameres americana (Cram 1927)

An experimental infection model for the heteroecious spiruid nematode Tetrameres americana (Cram 1927) was developed. The cockroach Blattella germanica (L.) and the locust Locusta migratoria (L.) were found to serve as intermediate hosts for the parasite. T. americana larvae developed to full maturity in these intermediate hosts and were infective to young Lohman Brown chickens after 32 days in the cockroach and 28 days in the locust. The maximum length of the larvae was reached in the insects at 28-30 degrees C after 10-15 days, at which time the larvae measured up to 2.2 mm. The parasite did not develop in the cockroach Periplaneta americana (L.), the woodlouse Oniscus asellus (L.), or the pupal stage of the giant mealworm Zophobas morio (Fabricius). Trials in which chickens were infected directly without an intermediate host failed. Infection of 24 chickens with a dosage of 100 larvae was followed by weekly post-mortems until day 48 post-infection (p.i.) and used to describe the development of T. americana. The average establishment rate (%) and the average worm burden varied from 16.5 to 30.8. The total numbers of parasites recovered ranged from 9 to 40. During mating, in the first 2 weeks p.i. females and males were equally abundant, whereas from day 20 p.i. twice as many females were recovered. From day 13 p.i. the females average length fluctuated between 2.6 and 3.7 mm, whereas they reached their maximum width of 2.4 mm on day 48 p.i. Males reached their full length after 27 days p.i. and measured up to 6.7 mm.

First report of five nematode species in Phasianus colchicus Linnaeus (Aves, Galliformes, Phasianidae) in Brazil

This paper deals with the first report of the nematodes Dispharynx nasuta (Rudolphi, 1819) Stiles & Hassall, 1920, Gongylonema ingluvicola Ransom, 1904, Oxyspirura mansoni (Cobbold, 1879) Ransom, 1904, Subulura brumpti (Lopez-Neyra, 1922) Cram, 1923 and Tetrameres fissipina (Diesing, 1860) Travassos, 1914, parasitizing the ring-necked pheasant, Phasianus colchicus Linnaeus, 1758 in Brazil. Morphological data on the parasites as well as on the prevalence, mean intensity, mean abundance and range of intensity of the nematodes in the infected birds are provided.

Tetrameres americana Cram (1927) populations in chickens infected with different dose levels

Three groups of 20-45 Lohman brown chickens aged 3 weeks were orally infected with doses of 25, 100 and 400 Tetrameres americana, respectively. Fifteen chickens were kept as uninfected controls. Every third week in a period of 12 weeks, 5-15 chickens were slaughtered and the proventriculi were examined for the presence of adult stages of T. americana. From day 21 post-infection, pooled feacal samples were examined for parasite eggs, whereas the weight gain of the chickens was monitored weekly. The parasite established the infection in similar rates in all the three groups, 9.5-15.2%, except on day 84 post-infection, when the establishment rate of the high-dose group was significantly lower (P < 0.005). The average worm burden increased with increasing dosages, though displaying the worm burden of the high-dose group as being roughly halved on day 84 post-infection, thus suggesting an expulsion of worms. Females were more abundant than males. The mean lengths of male and female specimens showed no significant differences between the groups. The egg output was also increased with increasing dosages with the earliest prepatent period of 38 days post-infection found in the high-dose group. Infected chickens exhibited no difference in weight gain in comparison with the controls. This study demonstrated that single infections with varying doses influenced the establishment rate and the worm burden but not the parasites egg excretion, worm size nor the weight gain and mortality of the final host.

Host age only partially affects resistance to primary and secondary infections with Ascaridia galli (Schrank, 1788) in chickens

Two experiments were conducted to compare the effect of chickens' age on resistance to primary and secondary infections with Ascaridia galli. In Experiment I, three groups, each of 80 female Lohman Brown chickens, aged one day, one month, or four months were compared. Within each group, 54 chickens were infected orally with 500 embryonated eggs and 26 were kept as non-infected controls. Weights were recorded weekly and five chickens in each group were slaughtered every 2 weeks for worm counts. At week 10 post-infection, 17 of the infected chickens and 18 of the controls were challenged with 500 eggs. In a replicate experiment (Experiment II), 35 one-day-old and 53 one-month-old female Lohman Brown chickens were infected orally with 500 A. galli eggs. Weights and fecal egg counts were recorded every week and infected chickens were necropsied every two weeks for determination of the worm burden. Chickens infected at one month of age excreted significantly fewer A. galli eggs when measured at 14 weeks of inoculation. The worms recovered from the one-month-old age group were significantly shorter than those from the chickens infected at one day of age in the first experiment. Worm burden and female fecundity values, however, were not significantly different between age groups in both Experiments I and II. Weight gains of infected chickens were not significantly different from the controls' and only a few chickens exhibited occasional slight diarrhea in both experiments. The results from these experiments demonstrate that the chickens' age only partially influences resistance to A. galli infection.

New morphological data on Cheilospirura hamulosa (Nematoda, Acuarioidea) by means of bright-field and scanning electron microscopy

This study reports on the morphology and morphometry of the nematode Cheilospirura hamulosa on the basis of bright-field and scanning electron microscopy. Specimens were recovered after necropsies of 28 Brazilian ring-necked pheasants ( Phasianus colchicus) and 30 domestic chickens ( Gallus g. domesticus) from backyard flocks. Measurements relate to the buccal capsule in the males and the distance of the excretory pore from the anterior end in both sexes, while the vulva and ovijector are studied for the first time. The most important taxonomic characters for the diagnosis of this nematode are the four long, longitudinal cordons which are neither anastomosed nor recurrent. They are composed of a groove with margins formed by cuticular specializations that change in appearance and width backward along the body and which run backward from the cephalic region ending near the posterior end as a cuticular depression. According to their morphology, these cordons could probably have nutritional, attachment and/or sensory functions.