Chicken production has increased over the past decade, resulting in a concomitant rise in the demand for more humane options for poultry products including cage-free, free-range, and organic meat and eggs. These husbandry changes, however, have come hand-in-hand with increased prevalence of Ascaridia galli infection, which can cause clinical disease in chickens as well as the occasional appearance of worms in eggs. Additionally, development of anthelmintic resistance in closely related helminths of turkeys highlights the need for closely monitored anthelmintic treatment programs. Manual faecal egg counts (FECs) can be time-consuming and require specialist training. As such, this study sought to validate an automated FEC system for use in detection and quantification of A. galli eggs in chicken faeces. Automated counts using the Parasight System (PS) were compared to traditional manual McMaster counting for both precision and correlation between methods. Overall, ten repeated counts were performed on twenty individual samples for a total of 200 counts performed for each method. A strong, statistically significant correlation was found between methods (R2 = 0.7879, P < 0.0001), and PS counted more eggs and performed with statistically significant higher precision (P = 0.0391) than manual McMaster counting. This study suggests that PS is a good alternative method for performing A. galli FECs and provides a new tool for use in helminth treatment and control programs in chicken operations.

Ascaridia galli (Nematoda: Ascaridiidae) is the most common intestinal roundworm of chickens and other birds with a worldwide distribution. Although A. galli has been extensively studied, knowledge of the genetic variation of this parasite in detail is still insufficient. The present study examined genetic variation in the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene among A. galli isolates (n = 26) from domestic chickens in Hunan Province, China. A portion of the cox1 (pcox1) gene was amplified by polymerase chain reaction separately from adult A. galli individuals and the amplicons were subjected to sequencing from both directions. The length of the sequences of pcox1 is 441 bp. Although the intra-specific sequence variation within A. galli is 0–7.7%, the inter-specific sequence differences among other members of the infraorder Ascaridomorpha were 11.4–18.9%. Phylogenetic analyses based on the maximum likelihood method using the sequences of pcox1 confirmed that all of the Ascaridia isolates were A. galli, and also resolved three distinct clades. Taken together, the findings suggest that A. galli may represent a complex of cryptic species. Our results provide an additional genetic marker for the management of A. galli in chickens and other birds.

Susceptability of Ascaridia galli to benzimidazole (BZ) was investigated using faecal egg count reduction test (FECRT), in ovo larval development test (LDT) and genetic markers (mutations at codons 167, 198 and 200 of β-tubulin gene). Six flocks (F1−F6) of a commercial laying hen farm with different number of exposure to BZ were recruited. The FECR was calculated by analyzing individual faeces (F1, F2, F4 and F5) before and 10 days after treatment. The LDT was performed on parasite eggs from pooled samples from F1 to F6 and LC50 and LC99 were calculated. DNA was extracted from 120 worms and sequenced for β-tubulin gene. In all flocks, the FECRs were above 95% (lower CI above 90%). No significant difference was observed (p > 0·05) among obtained LC50 (F1/F4 and F2/F5 vs F3/F6) in the LDT. However, LC50 and LC99 were higher than suggested values for declaration of resistance in other nematode species. No variation was observed in codon positions involved in BZ resistance. Overall, our results indicated lack of evidence of resistance to BZ in A. galli. More research is needed to confirm these results and to further optimize the existing tools for detection and monitoring of anthelmintic resistance in A. galli.

Eggs of chicken ascarids (Ascaridia galli and Heterakis spp.) are believed to be hardy and survive for long periods. However, this has not been evaluated quantitatively and our study therefore aimed to determine development and recovery of chicken ascarid eggs after burying in pasture soil. Unembryonated eggs were mixed with soil, placed in sealed nylon bags and buried at 7 cm depth in pasture plots April (spring, n = 72) and December 2014 (winter, n = 72). Eight randomly selected bags per season were used to estimate pre-burial egg recovery [0 week post-burial (wpb)]. Eight random bags were removed at 5, 12, 23, 38, 52, 71 wpb per season and additionally at 104 wpb for spring burial. The content of each bag was analysed for numbers and development stages of eggs. Eggs buried in spring were fully embryonated within 12 wpb. In contrast, eggs buried in winter were developing between 23 and 38 wpb, so that all viable eggs seemed to be fully developed by 38 wpb. About 90% eggs disappeared within 23 wpb (spring) and 38 wpb (winter). Small proportions (2–3%) of seemingly viable and infective eggs were still recovered up to 2 years after deposition. In conclusion, most eggs buried in temperate pasture soil seem to experience a heavy mortality within a few months after the deposition, especially during warm periods. However, a small proportion of eggs may survive and remain infective for at least 2 years.

The retail market share of organic eggs in Denmark is high, and the consumers expect high animal welfare standards in the organic production. Documentation of animal welfare is important, however, knowledge about the associations between animal-based welfare indicators is limited. The aims of the study were to investigate the associations between selected welfare indicators at two ages (peak and end of lay), and to examine the development with age of the chosen welfare indicators. The chosen welfare indicators were Ascaridia galli (roundworm) infection, Heterakis sp. (caecal worm) infection, keel bone damages, back feathering, body feathering, foot damages, comb colour and wounds on the body. An observational study with 12 organic egg farms was conducted in 2012 and 2013 with a total of 214 hens assessed individually at the peak and the end of lay. Insufficient data were obtained on helminth infection at the peak of lay. At the end of lay, all helminth infected hens were positive for A. galli, and only three of them had in addition a Heterakis sp. infection. Foot damages, pale combs and wounds on the body occurred at frequencies <5% and were therefore, together with the prevalence of Heterakis sp. infection, left out of the analysis of associations. A graphical model was used to analyse the associations between the remaining clinical welfare indicators, A. galli infection, housing systems and age of the hens at end of lay. A. galli infection was only directly associated with back feathering at end of lay (P=0.011) with an increased incidence of A. galli infection in hens with good back feathering. Between the two visits, the prevalence of hens with keel bone damages increased (P<0.001), and the plumage condition deteriorated (P<0.001), whereas the number of hens with plantar abscess (P=0.037) and pale combs (P=0.020) decreased. No significant differences were found for other foot damages or for skin damage. In conclusion, back feathering at end of lay provided information about a possible helminth infection, but this is not a useful indicator in daily on-farm management. In addition, evidence was found that the deterioration of the plumage condition with age was not only due to accumulation of damage over time.

Infectious diseases are major constraint that hinders the poultry industry. Among them parasitic diseases are very common and Ascaridia galli is one of the most common parasitic roundworms found in poultry. Haemorrhages, diarrhoea and listlessness are signs of infection. Parasitic infections such as A. galli are treated with chemical anthelmintics (piperazine, albendazole, levamisole, Ivermectin, benzimidazoles and fenbendazole). These synthetic chemicals can promote resistance, so there is need for alternative ways to treat the disease. Medicinal plants have the potential to combat such parasitism and the development of anthelmintic resistance appears to be very slow against such treatment. This review covers the studies related to the screening of plant materials having in vitro and in vivo anthelmintic activities against A. galli throughout the world. Medicinal plants showing in vitro anthelmintic activity include Anacardium occidentale, Allium sativum, Tribulus terrestris, Bassia latifolia, Piper betle, Morinda citrifolia L.I, Cassia occidentalis L. and Aloe secundiflora while in vivo studies include the use of Psorelia corylifolia, Piper betle, Pilostigma thonningi, Caesalpinia crista, Ocimum gratissimum and Anacardium occidentale. In conclusion, medicinal plants appear to have good anthelmintic activities in poultry and may substitute conventionally used synthetic drugs, and their use may moderate drug resistance in endemic pathogen populations and drug residues in poultry meat.

The population dynamics of Ascaridia galli was studied in 70 ISA Brown layer pullets, 42 of them were each experimentally infected with 500 embryonated A. galli eggs and 28 chickens were kept as uninfected controls. Six chickens from the infected group and 4 from the control group were necropsied at 3, 7, 10, 14, 21, 28 and 42 days post-infection (d.p.i.). The mean worm recovery varied from 11–20% of the infection dose with the highest recovery at 3 d.p.i. and the lowest at 21 and 42 d.p.i. (P < 0·05). More larvae were recovered from the intestinal wall than from the content (P < 0·0001) and intestinal content larvae were longer than those from the wall (mean length 1·6 and 1 mm, respectively, P < 0·0001). Although larvae were growing over time, a population of small-sized larvae (length  < 1 mm) was recovered at all d.p.i. During the first week of infection most of the larvae were located in the anterior half of the jejunoileum but they moved posteriorly with the age of infection. Thus, a subpopulation of larvae mainly in the lumen grew with time while another subpopulation remained small and associated with the mucosa. During the infection both subpopulations moved to a more posterior localization in the gastrointestinal (GI) tract.

This study examined whether Ascaridia galli infection can be controlled by dietary non-starch polysaccharides (NSP) in chickens. One-day-old chicks were fed either a basal diet (CON) or CON plus insoluble NSP (I-NSP), or CON plus soluble NSP (S-NSP) for 11 weeks. Three weeks later, birds from half of each feeding group were inoculated with 250 embryonated eggs of A. galli, and slaughtered 8 weeks post-infection to determine worm counts. Both NSP diets, particularly S-NSP, increased prevalence of infection (P<0·05) and worm burden (roughly +50%) of the birds (P<0·001). A. galli infection caused a less efficient (P=0·013) feed utilization for body weight gain (BWG) resulting in lower body weights (P<0·001) irrespective of type of diet consumed. NSP-fed birds, particularly those on I-NSP, consumed more (+8%) feed per unit BWG and showed retarded (P<0·001) BW development compared to CON-fed birds. Intracaecal pH was lowered by S-NSP (P<0·05). Both NSP diets increased the volatile fatty acids pool size in caeca (P<0·001) with S-NSP exerting a greater effect (+46%) than I-NSP (+24%). It is concluded that both NSPs supplemented diets alter gastrointestinal environment in favour of the nematode establishment, and thus have no potential for controlling A. galli infection in chickens.

Employing papain as the enzyme and agarose bound Ricinus communis agglutinin as the affinity gel, a glycoprotein has been isolated and purified from the surface of Ascaridia galli. The glycoprotein shows an apparent molecular weight of 68 kilo daltons and contains fucose, galactose, rhamnose and glucosamine as sugar moieties. Only 2% of its entire molecule has been found to possess α-helical configuration.

Inorganic analysis of Ascaridia galli has shown the levels of sodium, potassium, copper, magnesium, calcium, zinc, iron, nitrogen, phosphorus, sulphur, chlorine and cobalt (expressed as percentage of dry weight) to be higher in females than in males.

Male Hisex chicks were used in two experiments to investigate the interaction between Ascaridia galli infection and supplemental copper from basic and neutral salts. This was assessed by means of body weights, mortality, parasite burden and liver copper level. Cu2(OH)3Cl reduced the number of parasites but CuSO4.5H2O and CuCO3.Cu(OH)2.nH2O did not affect the parasite burden.

The possibility of safe immunization of chicks at an appropriate age with a double-dose irradiated Ascaridia galli vaccine given orally at two weeks interval was explored. Chicks immunized at 7 or 10 days of age were not affected adversely since they did not develop any clinical signs and there was no worm establishment after challenge infection. Immunization also elicited detectable circulating antibody titres, with IHA and the conglutinating complement absorption test having a tendency to be enhanced after the booster dose.

The metabolism of 5-hydroxytryptamine (5-HT), octopamine (OA) and dopamine (DA) by adult male Ascaridia galli was investigated by incubating worms cut into 5 mm lengths with radio-isotope labelled amine. [14C]5-hydroxytryptamine and [14C]octopamine were taken up by the tissues and were metabolized to apolar products that co-chromatographed using both high-performance liquid chromatography and thin-layer chromatography with N-acetyl 5-hydroxytryptamine (NA5-HT) and N-acetyloctopamine (NAOA), respectively. N-acetylation was by far the most important reaction detected under these experimental conditions. A brief incubation of cut worms with [3H]dopamine resulted in the formation of a radio-isotope labelled metabolite that co-chromatographed with N-acetyldopamine (NADA) on reversed-phase high-performance liquid chromatography. The N-acetyltransferase activity towards 5-hydroxytryptamine and octopamine was detected in crude homogenates of male worms only when the co-substrate, acetyl CoA, was added to the reaction mixture. This enzyme activity appeared to be mainly localized in a 40 000 g supernatant fraction. The failure of previous studies to detect N-acetylation of biogenic amines in tissue homogenates of nematodes may have been due to the low levels of acetyl CoA present in these enzyme preparations.

Evidence for the presence of adipokinetic hormone/hypertrehalosaemic hormone (AKH/HrTH)-like peptides in the parasitic nematodes Ascaridia galli and Ascaris suum has been obtained using insect bioassays which measure hyperglycaemic responses to peptides belonging to the AKH/HrTH family of insect hormones. A peptide fraction extracted from heads and tails of Ascaridia galli evoked a dose-dependent hyperglycaemic response when injected into the cockroach, Periplaneta americana. Maximal bioactivity was obtained with material that was equivalent to 38 mg (wet weight) of nematode. Bioactivity appeared to be highest in extracts from heads and tails of both male and female worms and could be fractionated into at least three peaks of hyperglycaemic activity by reversed-phase high-performance liquid chromatography. An extract from heads and tails of A. suum also evoked a hyperglycaemic response when injected into the cockroach, Blaberus discoidalis. The bioactivity was inactivated on incubation with pure endopeptidase 24.11, confirming the peptidic nature of the bioactive material. These results provide evidence for the existence of peptides related to the insect AKH/HrTH family of peptides in parasitic nematodes.

Vasoactive intestinal polypeptide (VIP)-Hke protein was detected by dot blot analysis in the excretions/secretions (E/S) of Nematodirus battus and Ascaridia galli and was confirmed in the E/S of Nippostrongylus brasiliensis. ELISA analysis showed that N. brasiliensis E/S contained the highest proportion of VIP-like protein (28·04 pmoles/mg of total E/S protein) and A. galli E/S contained the lowest (10·89 pmoles/mg of total E/S protein). Peptide histidine isoleucine (PHI)- like protein was detected by dot blot analysis in the E/S products of N. brasiliensis, N. battus and A. galli. ELISA analysis suggested that A. galli E/S contained the highest proportion of PHI (20·77 nmoles/mg of total E/S protein) and N. battus E/S contained the lowest (0·67 nmoles/mg of total E/S protein). The possible significance of VIP-like and PHI-like substances in the E/S of gastrointestinal nematodes is discussed.

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.