Dispersal of the northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago), and the chicken body louse, Menacanthus stramineus (Nitzsch), among thirty strains of egg-type hens in a caged laying house

Genotypic and Dietary Effects on Egg Quality of Local Chicken Breeds and Their Crosses Fed with Faba Beans

The quality of chicken eggs is an important criterion for food safety and the consumers' choice at the point of sale. Several studies have shown that egg quality can be influenced by the chickens' genotype and by the composition of the diet. The present study aimed to evaluate the effect of faba beans as a substitute for soybeans in the diet of chickens originating from traditional low-performance breeds in comparison with high-performing laying type hens and their crosses on egg quality parameters. Chickens of six different genotypes were fed either with a feed mix containing 20% faba beans with high or low vicin contents or, as a control, a feed mix containing soybeans. The genotypes studied were the local breeds Vorwerkhuhn and Bresse Gauloise, as well as commercial White Rock parent hens and their crosses. Yolk weight, Haugh units, yolk and shell color, the frequency of blood and meat spots and the composition of the eggs were significantly influenced by the genotype. The feeding of faba beans had an effect on yolk and shell color, Haugh units and shell portion, while there was no significant influence on the frequency of blood and meat spots.

Beak condition drives abundance and grooming-mediated competitive asymmetry in a poultry ectoparasite community

OBJECTIVE

Ornithonyssus sylviarum (northern fowl mite) and Menacanthus stramineus (chicken body louse) are key poultry pests currently controlled by exclusion or pesticide application. We studied how host beak condition affected their populations over time and how the lice and mites might interact on a host.

METHODS

Beak-trimmed or beak-intact white leghorn hens were infested initially with either mites or lice and subsequently challenged using the alternate ectoparasite species (reciprocal transfer), while other hens harboured only the initial ectoparasite species.

RESULTS

Beak-trimmed hens had far higher ectoparasite numbers relative to beak-intact hens, and the 2 ectoparasites showed evidence of grooming-mediated competitive asymmetry. On beak-trimmed hens, larger numbers of lice quickly nearly completely excluded mites in competition for enemy-free space (lower abdomen), while in the reciprocal transfer mites did not affect louse numbers on beak-trimmed hosts. The 2 ectoparasites co-existed on beak-intact hens, which were better able to defend the lower abdomen habitat by grooming.

CONCLUSION

Lice are somewhat less damaging and much easier to control relative to mites, and might be used to eliminate mites in commercial, beak-trimmed flocks. Beak trimming impairs host grooming and contributes greatly to the high ectoparasite populations seen in commercial flocks. The study adds incentives for poultry breeders to develop more docile hen strains that can be held without beak trimming. This has advantages both to welfare advocates and producers who may no longer need to use insecticides for pest control or be concerned about worker exposure to pesticides.

Review of the carriage of zoonotic bacteria by arthropods, with special reference to Salmonella in mites, flies and litter beetles

This systematic review considers the relationship between arthropods commonly found in and around livestock premises and zoonotic bacteria. The principal focus is upon insects and arachnids on poultry units, where houses, litter and manure provide good conditions for the growth, multiplication and protection of flies, beetles and mites, and where zoonotic pathogens such as Salmonella and Campylobacter are prevalent. Other members of the Enterobacteriaceae and the taxa Clostridium, Helicobacter, Erysipelas and Chlamydiaceae are also discussed. Salmonella is widely distributed in the flies of affected livestock units and is detectable to a lesser degree in beetles and mites. Persistent carriage appears to be common and there is some field and experimental evidence to support arthropod-mediated transmission between poultry flocks, particularly carry-over from one flock to the next. Campylobacter may readily be isolated from arthropods in contact with affected poultry flocks, although carriage is short-lived. There appears to be a role for flies, at least, in the breaching of biosecurity around Campylobacter-negative flocks. The carriage of other zoonotic bacteria by arthropods has been documented, but the duration and significance of such associations remain uncertain in the context of livestock production.

EFFECTS OF HOST SOCIALITY ON ECTOPARASITE POPULATION BIOLOGY

Theory predicts a positive relationship between parasite infection intensity and host density. However, this generalization is complicated in natural systems by differences in life history among parasite taxa, e.g., transmissibility. Accordingly, predictions relating host density to parasite load should be specific to each parasite taxon. To illustrate this, we studied parasites that differed greatly in life history in the context of the Galapagos hawk's (Buteo galapagoensis) variably cooperative mating system. Two louse (Phthiraptera) species were collected: Colpocephalum turbinatum (Amblycera), with 53 host species, and Degeeriella regalis (Ischnocera), with 10 host species, although B. galapagoensis was the only known Galapagos host. Sixty territorial adult male hawks from 26 groups of 1-6 males were quantitatively sampled for lice. Average abundance and intensity of C. turbinatum but not D. regalis were significantly larger in large groups of hawks than small groups. Males from the same polyandrous group harbored significantly correlated abundances of C. turbinatum but not D. regalis. Prevalence, average abundance, and intensity of C. turbinatum were significantly higher than D. regalis. These are the first results to demonstrate significant differences in a suite of population responses between these louse suborders in the context of host sociality.

Long term dynamics of dermanyssus gallinae in relation to mite control measures in aviary systems for layers

1. The dynamics of the poultry red mite, Dermanyssus gallinae, in aviary systems for layers were studied in an empirical study in Sweden between 1994 and 1997. Fluctuations were monitored with mite traps at monthly intervals during 3 laying cycles at each of 2 commercial poultry farms. 2. When mites were first detected in the system it then took about 5 months for the populations to reach equilibrium levels around which they fluctuated. Within flocks when the population growth was unaffected by temporary control activities, it was demonstrated that the mite populations were significantly denser in summer than in winter. 3. Current control methods had limited effects as mite populations were only temporarily suppressed. One exception was the control achieved with permethrin impregnated plastic strips, which reduced the population at equilibrium level to approximately 22%, compared with the previous flock. 4. The distribution of mites was patchy horizontally, along the aviary system, at low burden wlhereas it became more evenly dispersed at equilibrium. 5. Significant differences in vertical mite distributions that correlated with the hybrids used and their rearing conditions were also observed. In flocks with brown hens, mites gathered at the lower tiers, whereas they were found at the highest tiers in association with white hens. As the hens are attacked mainly at night-time the most likely explanation is that the mites adjust their behavioural pattern to the birds' roosting behaviour.

Topical application of garlic reduces northern fowl mite infestation in laying hens

Northern fowl mites (NFM) are external parasites that can lower egg production and cause anemia and even death in laying hens. An experiment was conducted with New Hampshire Red and Single Comb White Leghorn laying hens. Hens were individually caged and provided a complete laying diet and water ad libitum. Hens were assigned to groups in a way that assured that treatments, within each breed, would be applied to comparable numbers of birds with light and heavy mite infestations. Each hen was sprayed around the vent with either water or 10% garlic juice in water. Spraying continued each week for 3 wk. During the fourth week, each bird was scored for the presence of NFM on its skin and feathers. A small snippet of feathers was removed from below the vent of each hen and placed in a labeled petri dish with a round, white filter paper insert. The NFM content of each dish was scored by two individuals approximately 1 h after sampling. There was no significant difference in the NFM scores for hens based on breed or future treatment. After the birds were treated for 3 wk, there was no significant difference in external NFM scores based on breed. There were significantly fewer NFM on the birds treated with garlic juice compared with controls, based on external and petri dish scoring (P < 0.002 and P < 0.04, respectively). The reduction in external NFM score was also significant (P < 0.004), with controls declining approximately 0.2 units, whereas garlic-treated hens had a 1.8-unit decrease in external NFM score. Topical application of garlic juice may be an effective way to decrease NFM in laying hens.

Monitoring northern fowl mites (Acari: Macronyssidae) in caged laying hens: feasibility of an egg-based sampling system

Northern fowl mites were monitored on a caged-layer operation in southern California for 22 mo. Three experienced observers underestimated actual numbers of mites in the vent region approximately 80% of the time. Errors were higher for heavy infestations. Observer estimates were highly correlated with each other (r > 0.89, P < 0.01) and with mite numbers estimated by vent feather removal (r > 0.82, P < 0.01). Mites on hens varied between houses and over time. Molting consistently reduced mite numbers, but did not eliminate then in a flock. Long-term monitoring of individual sentinel hens demonstrated that some hens would support high numbers of mites for several months or more. Use of a new sequential hen sampling plan required approximately 1 min per hen, if mite numbers were estimated. At this site, treatment decisions often could be reached in < 20 min per house. Mite scores (index of estimated mites per hen) were well correlated with percentage of hens infested in both test houses. In a chronically infested house, prevalence of mites on eggs averaged 8.5%, with a range of 0-55%. Applications of tetrachlorvinphos-dichlorvos by the producer appeared to be based on mites on > about 20% of eggs. The chemical was marginal for controlling mites on hens (25% reduction in percentage of hens infested), but effectively reduced mites on eggs (95% fewer mites on eggs at 1 wk and 90% at 2 wk). When data were grouped by mite index score on hens, there was a strong relationship (r2 = 0.83, P < 0.01) between mite prevalence on eggs and the scores of the hens which laid them. Sampling 100 eggs evenly spaced in a house required < 7 min, and adult mites were easily seen. Sampling mites on eggs appears to be useful to localize at least high-level infestations, and egg-based sampling for mites merits further investigation.

Ectoparasite virulence is linked to mode of transmission

Theory suggests that the evolution of parasite virulence is linked to the dynamics of parasite transmission. All else being equal, parasites transmitted vertically from parents to offspring should be less virulent than parasites capable of horizontal transmission to unrelated hosts. This is because the fitness of vertically transmitted parasites is tightly linked to the reproductive success of the host, whereas the fitness of horizontally transmitted parasites is relatively independent of host reproduction. The virulence-transmission relation has seldom been tested because of difficulties inherent in comparing virulences of different parasite-host systems. We compared the virulence of lice and mites infesting a single group of captive rock doves (Columba livia). Lice, which were vertically transmitted, had no detectable effect on host fitness, whereas horizontally transmitted mites drove host reproductive success to zero. These results, in conjunction with a survey of the literature, support the hypothesis that ectoparasite virulence is linked to the mode of transmission.

Correlation of estimated and actual northern fowl mite populations with the evolution of specific antibody to a low molecular weight polypeptide in the sera of infested hens

In order to demonstrate the population dynamics of the northern fowl mite (NFM), Ornithonyssus sylviarum (Canestrini and Fanzago), and to characterize the chicken's immune response to the mites, White Leghorn hens were infested with mites. Visual estimates revealed populations peaked on Wk 5, 4, and 3 after being infested with 10, 50, or about 2,000 mites, respectively. Individual feathers pulled from the vent area of hens 4 wk (28 days) after the hens were infested with either 10 or 50 mites had means of 7,513 and 7,009 mites, respectively. Estimated mean total populations of NFM on these same hens were 182,000 and 258,000, respectively. In two replications, actual counts of viable NFM following infestation with 50 mites increased ca. 10-fold by the 2nd wk after infestations were established in the feathers and then another two-fold during the 3rd wk. Populations in the 4th wk were about one-third of levels observed during the 3rd wk and continued to decline rapidly. Western blot analyses demonstrated the appearance of a mite-specific antibody in sera of White Leghorn hens that was approximately proportional in time of appearance and intensity to estimated NFM populations. Detection of mite-specific antibodies in the hens' sera continued through 12 wk of the study even though mite populations declined after 3 to 6 wk. The rapid increase and then decline of NFM following infestation in previously uninfested chickens and the fact that the immune response persisted strongly suggests that the population decline was due to an immune response. Therefore control of the mite population by a vaccine may be possible.

Effect of biologically active plants used as netst material and the derived benefit to starling nestlings

The European starling Sturnus vulgaris preferentially incorporates fresh sprigs of particular plant species for use as nesting material. Chemicals found in these plants may act to reduce pathogen and ectoparasite populations normally found in nest environments. The present experiments were performed to test this Nest Protection Hypothesis. In the fild, we experimentally determined that wild carrot Daucus carota, a plant species preferred as nest material, effectively reduced the number of hematophagous mites found within nests relative to control nests without green vegetation. Chicks from nests containing wild carrot had higher levels of blood hemoglobin than chicks from control nests. However, there were no differences in weight or feather development. In the laboratory, we found that wild carrot and fleabane, Erigeron philadelphicus, (also preferred by starlings as nest material) substantially reduced the emergence of feeding instars of mites, while garlic mustard, Alliaria officinalis, (commonly available but not preferred) had little effect on the emergence of mites. We infer that preferred plant material may act to inhibit feeding or otherwise delay reproduction of mites, thereby reducing risk of anemia to developing nestlings.

Control of the northern fowl mite on inanimate objects by fumigation: laboratory studies

Laboratory studies were conducted to determine the efficacies of phosphine, methyl bromide, and sulfur dioxide as fumigants for the northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago), on inanimate objects. We were able to demonstrate that either methyl bromide or sulfur dioxide could kill all physiological forms of mites within 24 hr, which would be desirable for field use. Prosphine gas, released from Phostoxin pellets, had an LD95 of 18 hr for motile forms of the mites; however, it took 30 hr to kill the mite eggs. Therefore, it would be an unsuitable fumigant for practical field usage.

Residual activity of selected pesticides on laying hens treated for northern fowl mite control by dipping

Aqueous suspensions of malathion, stirofos, Ravap, and carbaryl formulations (.25 to 1.0%) were tested as dips for control of the northern fowl mite (NFM), Ornithonyssus sylviarum (Canestrini and Fanzago), on caged White Leghorn hens. Hens treated with Ravap showed symptoms of organophosphorus insecticide poisoning soon after treatment and some died as a result of the dip; however, dipping with the other insecticides did not result in any apparent toxic effects. Malathion gave residual control of mites for about 4 weeks posttreatment, but both stirofos and carbaryl dips gave complete control for at least 6 weeks against repeated challenges with the NFM. There were no significant differences in the percent hen-day egg production, feed consumption, or body weight of the hens that could be attributed to any of the chemical treatments.

Residues of stirofos (rabon) in eggs of laying hens treated for northern fowl mite control by dipping

Laying hens were treated with a wettable powder formulation of stirofos [Rabon, 2-chloro-1-(2,4,5-trichlorophenyl) vinyl dimethylphosphate] by dipping in a .5 or 1.0% actual ingredient (AI) water suspension of a 50% wettable powder (WP) stirfos formulation. Stirofos residues were detected in eggs within 1 day after treatment and reached maximum levels 3 days after dipping (.021 and .035 ppm in the low- and high-dose birds, respectively). After that time, levels of residues in eggs declined rapidly and no sample contained detectable quantities (less than .004 ppm) of stirofos after 21 days. Dipping may be a practical control method for the northern fowl mite on chickens, because stirofos dips effectively control this mite on laying hens for at least 6 weeks and because resulting residues in eggs are well below established tolerances.