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Reliable methods for detection of A. galli infection using excreta egg count (EEC) and ELISA assays to determine A. galli specific IgY levels in serum and yolk samples were compared from hens infected naturally and artificially. Artificially infected hens were used to generate samples for analysis of preferred detection methods and to generate contaminated ranges for use in the naturally acquired infection study in which Lohmann Brown hens (n = 200) at 16 weeks of age were randomly assigned to four treatments with five replicate pens. Hens of negative control (NC) ranged on a decontaminated area, hens of low infection, medium infection and positive control (PC) ranged on the areas previously contaminated by hens artificially infected with 250, 1000 and 2500 A. galli eggs/hen, respectively. Additionally, hens of PC were orally infected with 1000 A. galli eggs/hen. Anti A. galli antibody levels in hen serum (SIgY) and yolk (YIgY) were measured before range access, and 2, 7 and 12 weeks after access to the contaminated ranges. In a natural infection study, eggs were detected in the excreta of all hens 4 weeks after range access, with the exception of NC in which no eggs were detected. EEC increased to reach maximum value (2204 ± 307 eggs/g) after 11 weeks of range access and then declined at 12 weeks (905 ± 307eggs/g) (p 0.01). While SIgY OD values were not different in hens between any groups before range access, after 2 weeks, both SIgY and YIgY gradually increased in hens of PC (1.17 ± 0.03 and 0.88 ± 0.04) and medium infection (1.07 ± 0.03 and 0.96 ± 0.04) compared to low infection (0.38 ± 0.03 and 0.29 ± 0.04) (p 0.01) and NC. After 12 weeks, SIgY were similar in hens of PC, medium and low groups whereas YIgY was higher in hens of low infection group (p 0.01). Sensitivity of the serum and egg yolk antibody levels assay to detect A. galli infection was 100% and 96%, respectively, whereas the pooled EEC method yielded a sensitivity of 93%. The results of this study suggest that hens naturally infected with A. galli produce both SIgY and YIgY at different levels depending on the infection intensity and duration of exposure which allows the diagnosis of prior infection or early diagnosis of current infection. Use of the practical and non-invasive method of yolk sample analysis for detecting IgY can be just as informative as using serum samples to detect A. galli infection.

This study was conducted to determine: (1) the associations between anti-Fasciola hepatica antibody levels in milk and some productive and reproductive parameters in dairy cattle, and (2) the threshold antibody level associated with loss of productivity, at both herd and individual level. Anti-F. hepatica antibodies were analysed by MM3-SERO ELISA in milk samples from the bulk tanks of 490 dairy farms and from 686 lactating cows. The results of general linear model analysis revealed a significant (P0.05) negative association between the F. hepatica infection status at herd level, determined by analysis of specific antibodies in bulk tank milk, and the average herd milk production. Highly positive herds (MM3-SERO ELISA result0.405) produced an average of 1.5 kg milk/cow per day less than the negative herds. At cow-level, the mixed model analysis also revealed a significant (P0.05) association between anti-F. hepatica antibody levels and milk yield. A significant (P0.05) average reduction of 2 kg milk/day was observed in cows with highly positive ELISA results (0.762) in relation to cows with negative results. The results of the study led us to conclude that MM3-SERO ELISA is a powerful tool that can be successfully applied, if appropriate "economic thresholds" are established, to identify herds and cows suffering from milk production losses associated with natural infection by F. hepatica.

Antibody levels to Toxocara canis L2 excretory/secretory antigens were examined by ELISA in 400 serum samples from sheep in Powys and Gwent, Wales. A positive OD value was set at the mean +/-3S.D. of 45 control samples. Seroprevalence increased with age. Seven percent and 13% of 6-month-old sheep showed positive OD values as did 16% of 10-month-old, 27% and 31% of 15-month-old and 47% of cull ewes. Analysis of variance showed a significant increase in ELISA OD values among the seropositive sheep with increasing age of sheep.

Pasteurised and ultra high temperature (UHT)-treated milk were tested over the period November 1997-February 1998 in order to evaluate the applicability of an hypodermosis ELISA test on commercial milk samples. Milk samples from six dairy companies were analysed and the development of anti-Hypoderma antibodies recorded for the period from September 1998 to June 1999. For one dairy (no. 3) bulk milk samples were also obtained from the tankers, transporting milk away from the farms, and analysed; the results were compared to the parasitological status of the cows whose milk had been collected on the farms. Out of 32 pasteurised samples tested, 23 were positive, exceeding the cut-off (22%), while 9 samples were negative. UHT milk was always negative. The antibody levels in milk samples from four of the six companies were highest during January and decreased gradually during February to May 1999. The bulk milk samples also had high antibody levels and 47.2% of milk producing cows had lesions of hypodermosis. It was concluded that testing commercial milk for antibodies is an efficient way of detecting the presence of hypodermosis in cattle, especially in those countries for which no data on this disease are available.

Development of vaccines against canine visceral leishmaniasis (CVL) may provide a prophylactic barrier, but antibody response detected by standard diagnostic techniques may not separate vaccinated from naturally infected dogs. Moreover, anti-Leishmania antibody levels in vaccinated dogs may be detectable for months. Accordingly, the aim of the present study was to comparatively evaluate an "in-house" ELISA with three serological tests officially adopted by the Brazilian Ministry of Health for the diagnosis of CVL in dogs vaccinated with Leishmune(®). A total of 18 mongrel dogs were submitted to a complete protocol of the vaccine, monitored and evaluated in 5 times (T0-T4) up to 180 days after T0. Twenty-one days after the first dose (T1), 50% of the dogs were seropositive by the "in-house" ELISA and 5.5% by IFAT, while by the official ELISA and DPP(®) CVL rapid test all dogs tested negative. At time T2, 42 days after of the first dose, 100%, 83.3%, 11.1%, and 5.5% of the dogs were seropositive by the "in-house" ELISA, IFAT, official ELISA kit and the DPP(®) CVL rapid test, respectively. Ninety days after the first dose (T3), 100%, 83.3%, 72.2% and 33.3% of the dogs were seropositive by the "in-house" ELISA, official ELISA kit, IFAT, and the DPP(®) CVL rapid test, respectively. Finally, at time T4, 88.8%, 33.3%, 11.1% and 5.5% of the dogs were seropositive by the "in-house" ELISA, official ELISA kit, DPP(®) CVL rapid test and IFAT, respectively. In conclusion, dogs vaccinated with Leishmune(®) cross-react by an "in-house" ELISA and by the three official Brazilian serological tests for the diagnosis of canine visceral leishmaniasis up to six months after the first vaccine dose, and may be mistakenly diagnosed and removed.

This study evaluated a vaccine made from crude rhoptry proteins of Toxoplasma gondii with Quil-A, which was administered to cats by the intranasal route. Eleven short-hair domestic cats were divided into four groups: G1 (n = 3) received three doses (200 μg/dose) of the rhoptry vaccine with Quil-A (20 μg); G2 (n = 3) received PBS with Quil-A (20 μg); G3 (n = 3) and G4 (n = 2) received only PBS. Treatments were administered at days 0, 21, and 42 by the intranasal route. Challenge was done to G1, G2, and G3 animals with 600 cysts of the VEG strain on day 51 (challenge day); G4 animals were unchallenged. The anti-T. gondii IgG and IgA antibody levels from sera were measured by indirect enzyme-linked immunosorbent assay (ELISA). At challenge, two animals from G1 revealed antibody levels for both IgG and IgA; oocysts were not detected in feces of these two cats. There were no differences in hematological values between groups throughout the experiment (p > 0.10). Preventable fractions were 67% in G1 and 0% in G2 and G3. Comparatively, G1 animals shed 89.3% and 90.8% less oocysts than G3 and G4, respectively. Two out of three cats were protected against T. gondii oocyst shedding when the rhoptry vaccine was administered by the intranasal route. This is the first study using crude rhoptry proteins as vaccine by the intranasal route in cats to evaluate protection against oocysts shedding.

A cross-sectional questionnaire survey was performed on dairy herds in Flanders (Belgium) to detect management factors that are associated with an increased gastrointestinal parasite infection level of adult dairy cows. At the end of the grazing season, information concerning general herd factors, pasture management and anthelmintic treatment strategy was obtained from 956 herds. A bulk tank milk sample was obtained from 779 out of the 956 herds and the antibody levels (ODR) against Ostertagia ostertagi were determined. The associations between ODR and herd management factors were studied by two linear regression models. The first model evaluated the effect of general herd factors and the level of the cows' exposure to pasture. Large sized herds had significantly lower ODRs as compared to medium (P=0.001) or small sized herds (P=0.03). Herds with only dairy cows had lower ODRs than herds with both dairy and beef cows (P=0.02). An increased exposure to pasture of the cows was associated with higher ODRs (P0.001). The second model was built to evaluate the effect of pasture management factors and anthelmintic treatment strategy. Later turn-out on pasture (P0.001) and mowing (P=0.002) were both significantly associated with lower ODRs. Cows that had a restricted grazing time per day tended to have lower ODR than cows that grazed 24 h per day (P=0.07). An increased exposure to pasture of the heifers was significantly associated with higher ODRs (P=0.001). No associations were found between ODR and calf related management factors, anthelmintic treatment strategy, time of turn-in, rotational grazing type or stocking rate. Later turn-out on pasture, mowing and restricting the grazing time per day are factors that can be applied immediately on dairy farms to reduce economical losses due to gastrointestinal nematodes.

Three commercial enzyme-linked immunosorbent assays (ELISAs) were compared for the detection of antibodies to Sarcoptes scabiei var. suis using experimental sera of six 8-week-old pigs after contact infection with Sarcoptes scabiei var. suis. Six non-infected pigs were monitored as a control group. Blood sera were taken once a week from all animals. After successful infection the pigs were treated with an antiparasitic agent (12 weeks post infection (p.i.)) and the antibody titres were monitored until they were negative. The antibody levels of the experimental pigs reached the cut-off level 5 weeks after introduction of an infected animal to the group and were positive by both the Sarcoptes-ELISA 2001® PIG and the Acar-Test P -ELISA®. Four weeks after treatment mean results showed optical densities (% OD) below the cut-off level in the Sarcoptes-ELISA 2001® and 8 weeks after treatment in the Acar-Test P -ELISA®. In the Chekit® Sarcoptest pigs had elevated antibody levels in comparison to control animals, but ODs remained below the given cut-off level at all times. In a second examination with Chekit® Sarcoptest (different lot) and at a lower cut-off level, the sera of most of the piglets tested positive. Eight weeks after treatment, four from six pigs still had positive OD values. Therefore this investigation showed a higher sensitivity for the Sarcoptes-ELISA 2001® and the Acar-Test P -ELISA® than for the Chekit® Sarcoptest. Different test sensitivities must be considered when serologic methods are used for the diagnosis of swine sarcoptic mange, especially for monitoring and controlling eradication programs.

Hypodermosis is a myiasis of cattle mainly found in the Northern Hemisphere. In Italy it has been reported primarily in southern regions with a farm prevalence reaching a peak of 85%, while few data are available in the north of the country. This paper reports the results of a serological survey carried out on hypodermosis in Vicenza province (northeastern Italy). During January and February 1999, bulk milk samples were collected from 224 dairy farms and tested, using an hypodermosis ELISA kit. Epidemiological data, such as farm location, herd size, number of cows, grazing management, treatments against Hypoderma larvae, presence of imported animals, were gathered and statistically analysed in relation to the serological results. In 15 farms the presence of warbles was monitored by manual palpation and larvae collected for identification.Ninety-seven (43.3%) samples were detected as positive, whereas 12 (5.4%) and 115 (51.3%) were inconclusive and negative, respectively. Thirteen farms were positive upon parasitological examination and the larvae collected were identified as Hypoderma bovis.Seroprevalence was highly correlated with the practice of free grazing and slightly, but significantly, correlated with the number of cows on the farm. The mean antibody level of positive herds was significantly higher on farms without imported animals. On farms with warbled animals there was a high inverse correlation between antibody level and quantity of milk in the tanks and the number of lactating cows. The ELISA test on bulk milk samples has been shown, under field conditions, to be a useful, cost-effective and easy test for the diagnosis of bovine hypodermosis.

The susceptibility and distribution of Trichinella spiralis infection in goats was examined in ten autochthonous kids, 2 months old and about 10 kg body weight. The animals were divided into two groups: one experimental group with eigth animals, infected with 10 000 T. spiralis ‘T1’ encysted larvae and a control group with two non-infected animals. All the animals of the experimental group infected by the parasite showed that Trichinella larvae have a special affinity for the tongue, masseters, diaphragm, flexor-extensor muscles, intercostal muscles and myocardium, in decreasing order. The ELISA test carried out showed the first increments of optical density (OD) on Day 16 postinfection (p.i.), peaking on Days 37–44 p.i. and remaining elevated from this day on, with a slight fall at the end of the experiment (Day 90 p.i.). No alterations were observed in the OD obtained in control animals throughout the experiment. The great muscular establishment of T. spiralis larvae and the sigmoidal evolution of antibody levels confirm the host character of the goat to the parasite.