Gallinarum Infection Research Articles

First report of typhlitis/typhlohepatitis caused by Tetratrichomonas gallinarum in three duck species

Two Red-breasted Mergansers (Mergus serrator), one Hooded Merganser (Lophodytes cucullatus), and one Common Eider (Somateria mollissima) from a German zoological collection died of necrotizing typhlitis/typhlohepatitis within 2 years. Using a newly established chromogenic in situ hybridization assay, numerous intralesional trophozoites of Tetratrichomonas gallinarum could be detected in formalin-fixed and paraffin-embedded tissues from the caeca and livers of the affected birds. Partial sequencing of the 18S rRNA-gene revealed two unique nucleotide sequences very similar to T. gallinarum strains isolated from avian and human hosts. One turkey kept in the same zoological collection succumbed to histomonosis (blackhead disease) confirmed with chromogenic in situ hybridization at the time of the first duck fatalities. This turkey also harboured T. gallinarum trophozoites within necrotic cell debris in the caecal lumen, which might be epidemiologically related to the T. gallinarum infections in the ducks.

Non-starch polysaccharides alter interactions between Heterakis gallinarum and Histomonas meleagridis

Nutrition of the host animal may not only influence interactions between the host and its parasites, but also relations between different parasites species residing on the same host. We investigated effects of insoluble and soluble non-starch polysaccharides (NSP) on establishment and development of Heterakis gallinarum in chicken being treated or left untreated against Histomonas meleagridis.Six groups of one-day-old birds were allocated to three diets, two on each diet. The birds were fed ad libitum either a basal diet (CON), or CON+insoluble NSP (I-NSP) or CON+soluble NSP (S-NSP) until an age of 11wk. At an age of 19d, one of each diet groups was prophylactically treated for 9d with dimetridazole (0.05%, w/v) via drinking water against histomonas. The remaining three groups were left un-treated. Two days after starting dimetridazole treatment (at 3wk), each of the 6 groups was divided into two sub-groups. One dimetridazole treated and one dimetridazole un-treated groups of birds on each diet (6 groups) were infected with 200 embryonated eggs of H. gallinarum that were previously harvested from histomonas-carrying H. gallinarum infected chickens. The remaining 6 groups of uninfected birds, either treated or left un-treated against H. meleagridis, served as controls. Worm burdens of infected birds were determined 8wk p.i.Treatment against H. meleagridis significantly increased incidence of H. gallinarum infection and average worm length in all infected groups independent of the diet consumed (p<0.001). An interaction between effects of diet and dimetridazole treatment on worm burden (p<0.001) indicated that the S-NSP diet resulted in lowest worm burden in dimetridazole un-treated birds, whereas it caused the highest worm burden in the treated birds (p<0.05). Furthermore, the treatment resulted in higher worm burdens when compared to un-treated birds on the corresponding diets (p<0.05). Infection with H. gallinarum impaired body weight (BW) of the chicks (p<0.05) and H. meleagridis aggravated this effect (p<0.05). Dimetridazole treated and un-treated uninfected birds developed similar BW (p>0.05). Both NSP supplemented diets resulted in lower (p<0.05) BW when compared with the CON diet, S-NSP being inferior to I-NSP (p<0.05).It is concluded that H. meleagridis harms the definitive host as well as H. gallinarum. Both insoluble and soluble NSP supplemented diets favor H. gallinarum infection while S-NSP additionally intensifies histomonas infection, which then impairs establishment and development of H. gallinarum.

Pathological and clinical findings and tissue distribution of Salmonella Gallinarum infection in turkey poults

This study aimed to experimentally induce Salmonella enterica subsp. enterica serovar Enteritidis (Salmonella Gallinarum) infection in turkey poults in order to detect S. Gallinarum using immunohistochemical, bacteriological, and histological procedures. The study included 90 white turkey poults that were divided into 3 groups (1-day-old, 3-week-old, and 2-month-old), each of which was orally inoculated with an inoculum of 0.3 mL of S. Gallinarum strain 9 broth culture that contained approximately 2 × 10^4, 1 × 10^6, and 1 × 10^9 cfu/mL, respectively. The duration of the experiment was 18 days. Clinical, pathological, and bacteriological findings were evaluated daily until 18 days post inoculation (pi). The most evident clinical symptoms in all 3 groups were diarrhea and somnolence, especially in 1-day-old group. S. Gallinarum strain 9 was isolated from organs and cloacal swabs up to 16 days pi. Inflammation and typical granulomatous nodules in the internal organs were observed in all 3 groups. Strong immunoreactivity was determined in the lungs, bursa of Fabricius, caecum, ileum, and cloaca of all infected poults up to 18 days pi. In conclusion, S. Gallinarum infection caused heterophilic granulomas, especially in the duodenum of turkey poults, and immunohistochemical analysis can be considered as an adjunct to bacteriological methods in the diagnosis of S. Gallinarum infection.

Evaluation of antibacterial effects of a combination of Coptidis Rhizoma, Mume Fructus, and Schizandrae Fructus against Salmonella

The antibacterial potential of a preparation of medicinal herbs for the treatment of salmonellosis was evaluated. The preparation contained a combination of methanolic extracts from Mume Fructus, Coptidis Rhizoma and Schizandrae Fructus, and is designated NP532. NP532 was tested against 26 different Salmonella stains. All these strains were affected by NP532 even though many of the salmonella strains were resistant to multiple antibiotics. The MIC values of this combination against the Salmonella strains varied from 0.49 to 7.8 mg/ml. The in vivo antibacterial activity of NP532 was examined using a S. Gallinarum infection chicken model. The chickens were initially infected with S. Gallinarum, and NP532 was then administered. This preparation was found to have major effects on mortality. The histopathological observations of the NP532 treated animals did not show any of the clinical signs and rarely showed histological damage associated with the disease. On the other hand, the untreated controls showed the clinical signs, e.g. congestion and necrotic changes in the liver, kidney, and spleen. This suggests that NP532 might be an effective treatment for salmonellosis.

Individual and combined effects of ochratoxin A and Salmonella enterica serovar Gallinarum infection on pathological changes in broiler chickens

A study was conducted to evaluate the individual and combined effects of ochratoxin A (OA) and Salmonella enterica serovar Gallinarum (S. Gallinarum) on gross and histopathological changes in broiler chickens. One hundred and seventy-six 1-day-old broiler chicks were divided into two groups of 88 chicks each; one group was fed a control mash diet, and the other group was fed a mash diet containing 2 parts/106 OA. On day 14, each group was further subdivided into two groups, with one group inoculated with S. Gallinarum intraperitoneally (1.25×1010 colony-forming units/0.5ml) whereas the other group was not inoculated with S. Gallinarum. Four birds from each group were sacrificed on 1, 2, 3, 5, 7, 10, 14 and 21 days post inoculation to record pathological changes in different organs. Gross and microscopic changes in OA-fed birds indicated the kidneys and bursa of Fabricius as the primary organs to be affected by this toxin. Gross and microscopic changes due to S. Gallinarum infection indicated the liver and spleen as the primary organs affected by this infection. The effects of OA on the kidney and bursa of Fabricius were enhanced following S. Gallinarum infection. Degenerative changes and interstitial nephritis in the kidneys, and lymphocyte depletion from bursal follicles were more pronounced and were observed earlier in the combination group. In conclusion, data indicate that birds fed OA and infected with S. Gallinarum will demonstrate increased pathology compared with birds fed OA alone or those infected with S. Gallinarum but not fed OA.

Observations on the occurrence of Heterakis gallinarum in laying hens kept on soil

The occurrence of Heterakis gallinarum infection in a flock of Rhode Island Red laying hens is described. These hens were entirely kept in houses on a farm for commercial egg production, where a deep litter production system was adopted. Faecal samples from 120 hens selected at random were examined by common flotation technique and modified McMaster’s technique. H. gallinarum eggs were detected in 50% of the examined samples with very low faecal egg counts (<50 eggs per gram of faeces). There was no evidence of clinical signs, gross pathological lesions, and consequences on production level linkable to heterakiasis. H. gallinarum is transmitted by direct ingestion of infective eggs from the soil and is one of the most important intestinal helminths of poultry due to the role it plays as vector of histomoniasis. In accordance with European legislation on the welfare of laying hens, a progressively increasing number of farmers can adopt breeding programs on soil. Periodic coprological examinations of chickens reared on commercial farms from areas throughout Italy are thus advisable to determine the exact distribution of H. gallinarum and the extent to which heterakiasis may influence health status and production of chickens in this country.

The effect of chitosan on body weight and protection against &amp;lt;i&amp;gt;Salmonella gallinarum&amp;lt;/i&amp;gt; infection in broiler chickens (short communication)

Abstract. Chitosan adipate was administered orally to broiler chickens to investigate its effect on body weight and protection against Salmonella gallinarum. The study was conducted on 80 six-day-old broiler chickens from the ROSS line that were divided in four groups (20 birds each): I – control; II – infected with S. gallinarum and treated with chitosan adipate; III – infected with S. gallinarum; IV – chitosan adipate treatment only. Chitosan salt was administered as a feed additive in an amount that guaranteed that the chitosan contained in the salts constituted 3% of the chicken diet. (Phenotypic characteristics of Salmonella gallinarum and Salmonella pullorum isolated from layers). The chickens were infected with a suspension containing 1800x106 bacteria in 2 ml (on the McFarland scale gruppe 3). The chickens pretreated orally with chitosan were highly resistant to S. gallinarum infection. The clinical symptoms and anatomicopathological changes in chickens infected with bacteria and treated with chitosan (group II) were weak in comparison with chickens infected with S. gallinarum only (group III). Weight gain was significantly higher (by about 12.5%) in the control group than in the chickens infected with S. gallinarum (group III). In the birds that were infected and treated (group II), and in those that were given chitosan (group IV), weight gain was about 2–2.5 % lower in comparison with the control group.

Differences in resistance to Salmonella enterica serovar Gallinarum infection among indigenous local chicken ecotypes in Tanzania

A study was conducted to evaluate the disease resistance potential in 105 chickens of six indigenous local chicken ecotypes in Tanzania by orally challenging 1-week-old chicks with 2.5 x 10(8) colony-forming units of virulent S. Gallinarum. For 14 days post infection, clinical signs, necropsy findings, antibody titres, packed cell volume, leukocyte population count, and viable bacterial cell counts in the liver and spleen were recorded. Clinical signs were recorded daily but other parameters were recorded on the day of infection, then on days 3, 6, 10 and 14 after infection. Clinical signs of fowl typhoid were evident in chickens from day 3 post infection and disappeared by day 9 post infection. Pathological lesions on sacrificed birds included enlargement of the liver and spleen with foci of necrosis on the liver, spleen and myocardium. The mean viable bacterial cell counts in the liver and spleen varied between ecotypes, although the differences were not statistically significant. There were significant differences in the leukocyte population in the peripheral blood, with one ecotype (Morogoro-medium) showing a consistent and significantly higher heterophil count compared with other ecotypes. It was concluded that there is a selectable resistance potential to S. Gallinarum among the local chicken ecotypes in Tanzania that may be attributable to non-specific host immune responses. Further studies are suggested.

Effect of ochratoxin A on broiler chicks challenged with Salmonella gallinarum

1. A study was conducted to evaluate the effects of ochratoxin A (OA) on broiler chicks challenged with Salmonella gallinarum. 2. One hundred and seventy-six 1-d-old broiler chicks were divided into two groups of 88 chicks each, with one group fed on a control mash diet and the other given a mash diet containing 2 ppm OA. On d 14, each group was further subdivided into two groups with one group infected with S. gallinarum and the other uninfected. 3. Following S. gallinarum inoculation on d 14, 4 birds from each group were killed at 1, 2, 3, 5, 7, 10, 14 and 21 d post inoculation. 4. S. gallinarum infection caused dullness, depression, weakness, increased thirst, droopy wings, ruffled feathers and greenish-yellow diarrhoea. S. gallinarum infection in the absence of OA caused 11·5% mortality which increased to 28·8% in the presence of OA. 5. Decreased body weight and reduced feed intake were observed in chicks fed on the diet containing OA. S. gallinarum infection also reduced the body weights of chicks, with the effects being more marked in chicks receiving OA. The OA diet led to increased serum levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, uric acid and creatinine, and decreased levels of total proteins, albumin, globulins, calcium and phosphorus. S. gallinarum infection did not cause significant alteration in any of the serum biochemical parameters. 6. Mortality and the severity of S. gallinarum infection in broiler chicks were increased by the presence of OA in the diet.

Effects of Fusarium moniliforme Culture Material Containing Known Levels of Fumonisin B1on Progress of Salmonella Gallinarum Infection in Japanese Quail: Clinical Signs and Hematologic Studies

To study the individual and combined effects of fumonisin B1 (FB1) toxicity and Salmonella serotype Gallinarum infection, Japanese quail (Coturnix coturnix japonica) were fed Fusarium moniliforme culture material (2.5%), 150 mg FB1/kg ration, and were subsequently challenged orally with Salmonella Gallinarum organisms (2 x 10(4) colony-forming units) at 21 days of age. The chicks were fed culture material containing FB1 from day 5 till the end of the experiment. After being infected with Salmonella Gallinarum, observations were made 1, 2, 3, 5, 7, 10, 14, and 21 days postinfection. The clinical signs of diarrhea with bloody discharges were more pronounced in the Salmonella-infected birds on the FB1 diet. Mortality caused by Salmonella Gallinarum increased by 12% in the presence of FB1. Mean body weights in both the Salmonella-infected and FB1-fed groups were significantly lower than those of the controls at almost all intervals. Mean values of hemoglobin, packed cell volume, and total erythrocyte count were slightly higher in birds fed FB1 but were lower in the Salmonella Gallinarum groups fed FB1 and plain chick mash. Anemia was evident, between 5 and 10 days postinfection, in quail chicks infected with Salmonella Gallinarum alone. Total leukocyte counts were higher in Salmonella-infected and FB1-fed groups because of an increase in the number of heterophils and lymphocytes. However, the increase in lymphocyte response to infection was lower by 4.27%-30.09% between 3 and 21 days postinfection in the FB1-fed chicks compared with chicks infected with Salmonella Gallinarum. Alanine transaminase and total serum protein were slightly higher in both the infected and FB1-fed groups. This study revealed that the continuous presence of fumonisins in the diets of quail chicks might increase the susceptibility to or the severity of Salmonella Gallinarum infection.

Comparison of the immune responses against Salmonella enterica serovar Gallinarum infection between naked neck chickens and a commercial chicken line

The immune responses of indigenous naked neck (NaNa and Nana) and normally feathered (nana) chickens against a Salmonella Gallinarum (SG) infection were evaluated and compared withth ose of a commercial line (B-380). Groups of 28-day-old chickens (NaNa, Nana, nana, and B-380) were immunized orally and subcutaneously with 50 μg of SG antigens. Control non-immunized animals were inoculated withsterile saline solution. All chickens were challenged with 1 LD50 of SG and mortality was recorded daily for 20 days. Antibodies to SG were measured in sera before immunization, before the challenge, 10 days after the challenge, and at sacrifice. Peripheral blood lymphocyte proliferation assays were performed using concanavalin A and SG antigens. Results showed that non-immunized Nana chickens exhibited the best natural resistance to Salmonella infection, since only 30% of them died. In contrast, all control B-380 chickens died by the 13th day. Immunization with SG induced immunity in chickens of all genotypes. Indigenous naked neck and normally feathered chickens showed a higher survival rate when compared with B-380 chickens. Immunized Nana chickens showed the highest antibody titres (P < 0.05) as well as the highest thymidine incorporation in peripheral blood lymphocytes stimulated with con A or SG antigens (P < 0.05). The results show that Nana chickens are the most resistant to SG infection and the best responders to vaccination with SG antigens.

Mycoplasma gallinarum Infection in Commercial Layers and Onset of Fatty Liver Hemorrhagic Syndrome

Fatty liver hemorrhagic syndrome (FLHS) was observed in each of three trials in which commercial layers were utilized to determine the effect of Mycoplasma gallinarum (MGn) on egg and eggshell quality parameters and egg production. In each of three trials, FLHS occurred 31-54 days later in MGn-inoculated hens as compared with the Mycoplasma-clean (control) hens. In trials 1 and 2, no therapeutic intervention was initiated to ameliorate FLHS. In trial 3, therapeutic intervention was instituted and consisted of the addition of 1 pound of choline chloride/ton of feed. Total mortality recorded throughout the duration of each trial and attributable to FLHS was not significantly different between the control and the MGn-inoculated treatment. However, FLHS-associated mortality in each of the three trials was numerically greater for the control treatment.

Pathology of an atypical strain of Pasteurella gallinarum infection in chickens

Gross and microscopic pathology caused by an atypical strain of Pasteurella gallinarum (Fresno strain) was compared in chickens with that caused by the American Type Culture Collection type strain. Ten 21-day-old broiler chickens were inoculated intranasally with 10 7 colony forming units or intramuscularly with 10 5 colony forming units of either strain. The birds were killed 7 days later, and gross and microscopic lesions were studied. Grossly, there was extensive white discoloration of pectoral muscles with mild fibrinous exudate in birds inoculated intramuscularly with the Fresno strain of P. gallinarum . Most of these birds also had severe fibrinous exudation over the heart, the capsule of the liver, the air sac, and in the hock joints. Microscopically, there was severe chronic pyogranulomatous airsacculitis, pericarditis, perihepatitis, myositis, synovitis, and granulomatous pneumonia. One bird had severe acute multifocal hepatitis. From this study, it is evident that the Fresno strain of P. gallinarum was more pathogenic than the American Type Culture Collection type strain when given intramuscularly.

The effect of an experimental infection of the nematode Heterakis gallinarum on hand-reared grey partridges Perdix perdix

We compared 26 hand-reared grey partridges given an experimental infection of the caecal nematode Heterakis gallinarum with 26 uninfected ones. Under laboratory conditions after 91 days, there were no measurable clinical effects of the infection. We found no effect of treatment on the amount of food eaten or on caecal dropping production. However, treated birds, in particular females, developed slightly lower body mass (around 2%) compared to the controls. At post-mortem examination, we found a positive relationship between breast muscle mass and the number of worms collected from the caeca of treated birds. Treated birds with no worms when examined had smaller breast muscle mass (4.6%) compared to the uninfected control birds. These results are largely different to those found in a similar study that documented significant negative impacts on most of these factors in 8 infected birds compared to 6 controls. Its findings were used in a published model to support a hypothesis that H. gallinarum maintained in the environment by common pheasants, the primary host for this worm, could negatively affect wild grey partridge productivity and survival. In the same model our data would not support this hypothesis. Possible explanations for the different results from the 2 experiments are discussed. Together they suggest that only in certain, as yet unidentified circumstances, could experimental H. gallinarum infections have deleterious effects on hand-reared grey partridges.

Molecular epidemiology of Salmonella gallinarum in chickens in Tanzania

A molecular epidemiological investigation of Salmonella gallinarum infection in scavenging local chickens and commercial layers in Tanzania was conducted between August 1997 and April 1998. A total of 1152 chickens were randomly selected from 10 villages and seven commercial farms. For serological and cultural prevalence studies, 1152 blood samples and 912 cloacal swabs were collected. In scavenging local chickens, the individual serological and cultural prevalences were 6.3 and 0%, while the prevalences were significantly higher in commercial layers at 18.4 and 2.6% (P < 0.001), respectively. The risk of infection in flocks of scavenging local chickens that had contact with commercial chickens was six times greater than the risk of infection in flocks of scavenging local chickens that had no contact with commercial chickens. Thirty-four S. gallinarum isolated from commercial chickens in this study, together with 29 Tanzanian historical isolates, were characterized using plasmid profiling and ribotyping. Fifty-one isolates contained both 85 and 2.5kb plasmids, five isolates contained only one plasmid of 85kb, and seven isolates had no plasmids. Ribotyping using HindIII restriction endonuclease demonstrated seven different ribotypes. Forty-seven isolates had similar results in both typing systems, suggesting they belonged to one clone. It is concluded that S. gallinarum infection in chickens in Tanzania is more prevalent in commercial layers than in scavenging local chickens. One strain of S. gallinarum from chickens first isolated in a Dar es Salaam hatchery was found to be common throughout the country.

The role of shared parasites in the exclusion of wildlife hosts: Heterakis gallinarum in the ring-necked pheasant and the grey partridge.

1. A two-host shared-macroparasite model was parameterized from the results of infection and transmission experiments, to investigate whether apparent competition between the ring-necked pheasant (Phasianus colchicus) and the grey partridge (Perdix perdix), mediated via the shared nematode Heterakis gallinarum, could theoretically cause partridge exclusion. 2. Both the model created and the experiments conducted show that the bulk of H. gallinarum infection to partridges, when they occur in the same locations as pheasants, will be from the pheasants and not from the partridges themselves. This is due to R0 for the parasite being 1·23 when infecting pheasants, but only 0·0057 when infecting partridges. Thus, when the pheasant is present in the model the partridge population is impacted by the shared parasite but, when the pheasant is absent, the parasite is lost from the system. 3. Based on best available parameter estimates, the observed impact of H. gallinarum on the grey partridge may be sufficient to cause exclusion when the pheasant is present in the model. This supports the hypothesis that the UK grey partridge decline observed over the past 50 years may be partly due to apparent competition with pheasants. 4. Habitat separation between the two host species, where it decreases the rate of H. gallinarum transmission from the pheasant to the partridge, may allow them to co-exist in the field in the presence of the parasite. We predict, however, that grey partridge exclusion would still occur if separation was less than 43%.

Serological Response of Chickens to Infection with Salmonella gallinarum-S. pullorum Detected by Enzyme-Linked Immunosorbent Assay

The serological response to Salmonella pullorum and S. gallinarum infection in chickens was studied with an indirect enzyme-linked immunosorbent assay (ELISA). In broiler chickens, a more virulent strain of S. pullorum produced a significantly lower serum IgG titer than did a less virulent strain. In laying hens, the serum and egg-yolk IgG titers were very similar. In chickens infected with S. gallinarum, high IgG titers persisted for 30 weeks. In chickens reinfected with this strain, each reinfection was followed by transitory increases in IgG lasting no longer than 2 weeks. Serum samples from Brazil taken from a laying flock with evidence of fowl typhoid showed much higher antibody levels than did those from three uninfected flocks. Using lipopolysaccharide as the detecting antigen, infections caused by these salmonellae could be differentiated from those caused by other groups. Incorporation of the appropriate flagella antigen in the ELISA allowed differentiation between infections caused by S. pullorum and S. enteritidis.

Effect of Salmonella gallinarum Infection on Zinc Metabolism in Chicks

The effect of Salmonella gallinarum infection in chicks on serum, liver, and kidney zinc concentrations was studied. Within 48 h after intraperitoneal administration of the organism, serum zinc declined to approximately one-half the control value. In one experiment, the serum zinc concentration remained low for the 12 days of the experiment, whereas in a second experiment, the concentration gradually increased after 6 days postinoculation but never returned to the control value. Feeding as much as 500 ppm supplemental zinc did not prevent the infection-induced decline in the serum zinc concentration. The infection resulted in a sequestering of zinc in the liver; the kidney remained relatively unresponsive in this system. Fractionation of liver homogenates by gel filtration column chromatography revealed that the zinc in the livers of the infected animals eluted in a volume characteristic of metallothionein, whereas that of control animals was associated with high molecular weight proteins. Increasing the zinc content of the serum by repeated subcutaneous injections of zinc had no effect on mortality from this infection. Restricting feed consumption of uninfected chicks to that of infected animals did mimic the influence of infection of serum zinc and hepatic metallothionein concentrations.

Cecal and Hepatic Granulomas in Chickens Associated with Heterakis gallinarum Infection

Heterakis gallinarum infection was detected in the ceca of chickens with cecal and hepatic granulomas found at slaughter. The chickens were diagnostic submissions from four small backyard flocks in Saskatchewan. Detailed dissection of some cecal granulomas in one flock and pepsin digestion of cecal granulomas in the three other flocks demonstrated the presence of the parasite within granulomas in three of the flocks. A possible causal relationship between Heterakis gallinarum and the cecal and hepatic granulomas is discussed.

Survey of the health and husbandry of small poultry flocks in Great Britain.

An investigation into the health and husbandry of 15 small poultry flocks was undertaken. Each flock was visited in July and a questionnaire on management practices and disease history was completed. The flocks were clinically examined and serological tests for Salmonella pullorum, Mycoplasma gallisepticum, M synoviae, M meleagridis, Newcastle disease, infectious bursal disease, infectious bronchitis, eggdrop syndrome 76, adenoviruses and reoviruses were carried out. Oesophageal and cloacal swabs were cultured for mycoplasma and pullorum reactors were cultured. M gallisepticum, M synoviae, M meleagridis and M gallinarum infections were detected and serological reactions for all the viral diseases, except egg drop syndrome 76, were found. Evidence of Newcastle disease and pullorum disease was encountered. Lice were present in five flocks and mites in four flocks. Welfare standards varied.