Biomedical subjects

R Sánchez-Andrade

Publications and source records attributed to R Sánchez-Andrade.

At least 19 recordsLinked to original sources

PubMed2006

Analysis of the IgG antibody response against Paramphistomidae trematoda in naturally infected cattle. Application to serological surveys.

The IgG antibody response to Calicophoron daubneyi (Digenea: Paramphistomidae) excretory/secretory antigens was evaluated in naturally infected cattle from Lugo (Galicia, NW Spain) by using an ELISA procedure. Two studies were conducted, first a survey in 524 cattle separated into three groups according to age, G-1 (0-2 years old), G-2 (3-5 years old) and G-3 (> 6 years old). In the second study, three groups of cattle were employed: G-I, naturally infected; G-T, naturally infected and treated with oxyclozanide plus levamisole (Nilzan Plus); G-C, cattle maintained in a farm where C. daubneyi has never diagnosed. Variations on egg-output and haematic parameters (erythrocytes, haematocrite, leukocytes and lymphocytes) were also analyzed. The ELISA procedure showed that 61.2% of the cattle in the first study had been exposed to the trematode, but only 10.1% passed eggs in the feces. Age-association with egg-output was shown but not with the IgG values. In the second experiment, the administration of the anthelmintic reduced significantly the IgG kinetic levels and the C. daubneyi-egg-output was suppressed during 12 weeks in the G-T group. The values of red cells, haematocrite, leukocytes and lymphocytes increased significantly in the treated cattle 5 weeks after chemotherapy; however, new reduction after week 5 was recorded, as results of the challenge of these cattle. This is the first investigation in which evaluation of the IgG humoral response against C. daubneyi in cattle has been carried out. We proved that a notable IgG response in naturally infected cattle is induced, and can be detected by using an ELISA procedure. The IgG antibodies did not increase after challenge infection. Our results proved an important percentage of cattle were exposed to this trematode in the area of study and suitable measures for preventing this relationship must be considered.

Age Factors↗

PubMed2006

Toxocara canis larvae viability after disinfectant-exposition.

The effect of three routinely used disinfectants on the embryonary development of Toxocara canis eggs was evaluated both in vivo and in vitro. In the in vitro experiment, T. canis eggs were treated with the ethanol, sodium hypochlorite, and one commercial mix of benzalconium chloride and formaldehyde, and the embryonary development was assessed. After a period of 24 days incubation, ethanol was the best disinfectant because it prevented the development of the T. canis larvae 2 in the eggs, and sodium hypochlorite caused degeneration in 50% eggs. By using the commercial mix, 25% T. canis eggs developed to 2nd stage larvae. In the in vivo experiment, the embryonated eggs treated with the disinfectants were inoculated to mice, and their brain tissues were examined for larval presence on the 24th day postinfection. In addition, a control group was set up for comparison with the infected groups. No injury or T. canis larvae were observed in mice infected with sodium hypochlorite-treated eggs, opposite to that recorded in the animals infected with the commercial disinfectant-treated eggs. These results showed that both ethanol and sodium hypochlorite are very appropriate because of their full efficacy against infective T. canis eggs. Disinfection of kennels, animal shelters, cages, and veterinary clinics with one of these products to eliminate T. canis eggs and to avoid contamination is strongly recommended.

Animals↗

PubMed2006

Prevalences of gastrointestinal parasites in sheep and parasite-control practices in NW Spain.

A coprological survey to know the presence of gastro-intestinal nematode parasites infecting sheep was done in Galicia (NW Spain), an area with Atlantic climate where sheep production is replacing cattle due to the Agricultural Community Politics of the European Union. From September 2001 to November 2002, 1710 faecal samples were randomly collected from 49 sheep farms and examined by using the flotation technique to determine the prevalence of gastro-intestinal nematode parasites. The sheep-level prevalence was 100%, and the genera identified were Chabertia, Cooperia, Haemonchus, Nematodirus, Oesophagostomum, Teladorsagia, Trichostrongylus and Trichuris spp. A questionnaire was distributed to the farmers (at the same time as sampling) about parasite-control practices during the year before sampling (2000). Ninety percent (95% CI 81%, 98%) of the farmers said they used antiparasitic drugs occasionally, but none of them asked for a coprological analysis prior to the treatment and the efficacy of the drugs was never evaluated. A higher median EPG was observed in the treated sheep (163) than in the untreated ones (26). Chemotherapy was the only parasite-control practice. Flocks that treated according to the farmer's previous experience had higher median EPG (236) than other flocks (185 following the prescription of their veterinary clinician and 232 based on the commercial agent's counsel). Typically, one benzimidazole-treatment per year was applied in autumn and non-veterinary counsel was used. Sheep treated with imidotiazoles had lower EPG (144) than other drugs (164 for the benzimidazoles and 166 for the macrocyclic lactones). We found a higher median EPG in the sheep receiving two treatments/year (175) than in those treated only once per year (156). These results suggest lack of knowledge about worm-control strategies and anthelmintic use or unwillingness to apply such knowledge.

Animals↗

PubMed2006

A 2.9 kDa Fasciola hepatica-recombinant protein based ELISA test for the detection of current-ovine fasciolosis trickle infected.

The suitability of an enzyme linked immunosorbent assay (ELISA) test with a 2.9 kDa Fasciola hepatica-recombinant protein (FhrAPS) for diagnosing early and current-ovine fasciolosis was analyzed, and compared to that obtained by using a direct ELISA for detecting F. hepatica-circulating FhES antigens and to the coprological sedimentation for fluke egg quantitation. Fourteen Gallega autochthonous breed sheep were experimentally infected with metacercariae by a trickle system (small repetitive infections) and divided into two groups: G-I represented a primary infection for 34 weeks; G-R, animals with primary infection and reinfected 18 w.a.p.i. Seven sheep were left uninfected as the control group (G-C). Serum IgG antibody values against the FhrAPS rose rapidly by 1st w.a.p.i. in all infected sheep. Antibody levels in those with primary infection (G-I, G-C) peaked at 10 weeks, diminishing slightly and levelling from 16 to 34 weeks. Those with primary infection reinfected at 18 weeks had a rebound effect with the highest values observed. Circulating F. hepatica-ES antigens were detected by the 1st w.a.p.i. in all infected groups peaking at 6 weeks, decreasing rapidly to uninfected control values by 10 weeks of infection. Faecal egg-output started 11 weeks after primary infection. An increase in the IgG antibody as well as antigen responses to the FhrAPS and to anti-FhES from the 18 w.a.p.i. was recorded in G-T and G-R after the challenge infection. Antibody levels remained high whereas antigenemia values diminished after 6 weeks. A positive significant correlation between the IgG response against the FhrAPS and the F. hepatica circulating antigens (r2 = 0.428, p = 0.001) was obtained. In conclusion, our standardized diagnostic ELISA for fasciolosis based on the detection of IgG responses to the FhrAPS would be a valuable tool to diagnosis early and current F. hepatica-infections in sheep.

Animals↗

PubMed2005

Analysis of the humoral immune response to Oestrus ovis in ovine.

Antibody responses (IgG, IgM and IgA) against Oestrus ovis were analyzed in sheep and in first year grazing lambs from Sardinia (Italy) by an indirect-enzyme-linked immunoassay test and L2 O. ovis excretory/secretory antigens. Serum samples from 208 sheep were obtained prior to be slaughtered, and then heads were removed and cut open along their longitudinal axis to collect the parasites from the nasal cavities, turbinates and sinus. Besides this, blood samples were monthly collected from the lambs of G-1 (maintained under field conditions) and the lambs of G-2 (kept housed since birth to avoid Oestrus infestations) throughout a year. In the sheep, a positive significant correlation was observed between the number of first instar O. ovis larvae and the values of IgM, and between the second instar larvae and the IgG optical densities. In the lambs, all classes of antibodies increased significantly from July in G-1. The highest values of IgG were reached in September (IgG) and decreased in November-December. The IgM response peaked in November, and very low values of IgA were observed during the study. Matching these data with chronobiology of O. ovis in this region, we conclude that the first infection occurs on May, stimulating the production of humoral antibodies. The reduction of the IgG antibody levels starting from October means the beginning of the diapause while the IgM response seems to be associated to the presence of L1 in the nasal cavities. The data obtained led us to forecast an early treatment of the ovine on June-July, which should keep away from the maturation of O. ovis L1 larvae, avoiding the development of clinical lesions and interrupting the life cycle of this parasite.

Animals↗

PubMed2005

Comparison of Oestrus ovis metabolic and somatic antigens for the immunodiagnosis of the zoonotic myasis oestrosis by immunoenzymatic probes.

Control of zoonosis implies reduction of infected animal hosts, and the first measure consists of a suitable and accurate detection test. An experimental study for determining the most appropriate antigen (metabolic or somatic) to be used in the detection of the oestrosis (Oestrus ovis) zoonotic myasis by means of immunoenzymatic probes was carried out. A flock of 23 uninfected goats was maintained under field conditions to allow their infection in Sassari (Sardinia, Italy). Caprine were bled monthly and serum samples processed by means of an iELISA. After comparing these results to the chronobiology of O. ovis, we proved that the IgG humoral response against the metabolic antigens increased only during the period of real risk of infestation (when adults fly, from May to September), whereas the absorbances against the somatic products were positive from the beginning of the study (in January, prior to infection). We concluded that the excretory/secretory products are most useful and suitable for the immunodiagnosis of oestrosis in goats, because a direct relation between the development of O. ovis and the IgG humoral response is possible, allowing a more accurate diagnostic.

Animals↗

PubMed2004

Isolation, identification and expression of a Fasciola hepatica cDNA encoding a 2.9-kDa recombinant protein for the diagnosis of ovine fasciolosis.

A 400-bp Fasciola hepatica cDNA clone was isolated from an expression library by immunological screening using rat sera taken 2 weeks after experimental infection. The nucleotide sequence of the cDNA revealed the presence of an open reading frame of 78 bp which encoded a 25 amino acid polypeptide with a predicted molecular weight of 2.9 kDa. This polypeptide was expressed in bacteria as a GST-fusion protein and used for the production of specific antigen. The 2.9 kDa recombinant protein (APS) was evaluated against sera from experimentally infected sheep using an indirect ELISA, and the results were compared to those obtained using F. hepatica excretory/secretory products (ESP). The pattern of IgG was very similar both against the recombinant and the native proteins, increasing early following the infection. After treatment with triclabendazole, the IgG response against the APS seroreverted to negative values, whereas it remained elevated against the ESP. We conclude that this recombinant protein could be used in diagnostic assays for the identification of recently infected sheep.

Amino Acid Sequence↗

PubMed2004

Larval development of Aelurostrongylus abstrusus (Nematoda, Angiostrongylidae) in experimentally infected Cernuella (Cernuella) virgata (Mollusca, Helicidae).

The larval development of the cat lungworm Aelurostrongylus abstrusus was studied for the first time in the helicid mollusc Cernuella (Cernuella) virgata, in order to know its performance as intermediate host (I.H.). This snail is very common in the north-west of Spain. First-stage larvae (L1) of A. abstrusus were obtained by the Baermann-Wetzel method from the faeces of a naturally infected cat. Then, 120 specimens of C. (C.) virgata were infected with 500 L1/snail and maintained under laboratory conditions (20+/-2 degrees C). Every 2 days, from day 8 to day 76 post-infection (p.i.), three snails were killed in order to study the larval development of the parasite. Morphological features of the different larval stages were also recorded. The apparent rate of penetration of L1 into the snail foot was 65.5%, but only 4.78% completed their development to the infective stage (L3). The total number of larvae was 49.8+/-28.8 larvae/snail and the average number of L3 was 23.9+/-18.4 L3/snail. The first L2 and L3 were observed on day 12 and day 18 p.i., respectively. From day 52 p.i. onwards, all larvae were at the infective stage in the snail. Considering those results, it was concluded that C. (C.) virgata is a suitable I.H. for A. abstrusus.

Animals↗

PubMed2003

Prevalence of natural ovine fasciolosis shown by demonstrating the presence of serum circulating antigens.

The prevalence of fasciolosis in sheep (Galicia, Northwest Spain) kept under field conditions was determined by using a sandwich-enzyme-linked immunosorbent assay (sELISA). Serum Fasciola hepatica circulating antigens were captured by means of a rabbit polyclonal IgG antibody to F. hepatica excretory/secretory products. Results were compared to those obtained by faecal sedimentation and an indirect ELISA (iELISA) and excretory/secretory antigens. Prevalences were 39.1% by sELISA, 30.4% by faecal sedimentation and 56% by iELISA; 83.3% of the sheep were positive to any one of the three tests. We observed that 59.5% of the sheep examined had active fasciolosis, 29.1% (117) had antigenaemia, 20.4% (82) passed eggs, and 40 (10%) were positive to both probes. We conclude that there is a high prevalence of fasciolosis in sheep from the studied region, and that the combination of sELISA and coprological sedimentation is extremely helpful for demonstrating current fasciolosis, so its application can be strongly recommended for epidemiological surveys.

Animals↗

PubMed2003

Serum antibodies to Dicrocoelium dendriticum in sheep from Sardinia (Italy).

An indirect enzyme-linked immunosorbent assay (ELISA) with Dicrocoelium dendriticum excretory/secretory antigens was used to evaluate the presence of serum antibodies against the trematode in 738 sheep randomly chosen in Sardinia (Italy). Coprological sedimentation was used to discover egg-output. Seropositivity was detected in 86.2% tested sheep, whereas faecal prevalence was 6.7%; all that were faecal-positive also were ELISA-positive.

Animals↗

PubMed2003

Diagnosis of parasitic zoonoses by immunoenzymatic assays--analysis of cross-reactivity among the excretory/secretory antigens of Fasciola hepatica, Toxocara canis, and Ascaris suum.

Several parasitic infections such fasciolosis, toxocariosis or ascariosis are important zoonoses. During the infection with Fasciola hepatica, Toxocara canis and Ascaris suum, an important intraorganic phase in their hosts takes place, releasing antigens responsible for a humoral immune response, which enables the diagnosis of that parasitosis. A study to identify the existence of cross-reactivity among the excretory/ secretory antigens of F. hepatica, T. canis and A. suum was developed. One group of Sprague-Dawley rats was infected with 20 metacercariae of F. hepatica and another group remained uninfected as control. By means of an Indirect-ELISA, the rat humoral immune response (IgG and IgM) against the excretory/secretory antigens of F. hepatica was analysed and measured for cross reactivity with T. canis and A. suum. IgM cross-reaction was mainly observed in the first 10 weeks post-infection. IgG cross-reaction was observed throughout the study, and was maximal at the 2-3 weeks and 3-6 weeks post-infection, which corresponds to the intraorganic migratory phase of these parasites. The western-blot showed that the rat IgG recognised three proteins of 190, 160 and 33 kDa in the antigens from F. hepatica, T. canis and A. suum. The existence of cross-reactivity among these antigens seems to demonstrate also the presence of structural similarities, such as tegumental proteins. These results should be consider when immunoassay probes are used in the diagnosis of parasitic infections.

Animals↗

PubMed2002

Time-course analysis of coproantigens in rats infected and challenged with Fasciola hepatica.

The influence of a challenge infection during an acute or chronic primary infection on Fasciola hepatica-coproantigen kinetics was established in rats. Egg-output and IgG humoral responses were also established. Two primary-infected groups were reinfected at different periods, one 4 weeks after primary infection (w.p.i.) (acute phase) and the other 11 w.p.i. (chronic phase). Another group remained without reinfection as a control. Coproantigens were first detected in the group challenged on acute fascioliasis. The highest values of coproantigens were recorded in the group reinfected during acute fascioliasis and the lowest in the group challenged during chronic fascioliasis. The IgG responses to F. hepatica excretory/secretory antigens increased after reinfection. Neither the egg output nor the parasitic burden were significantly different among the three infected groups. Our results indicate that the time of challenge affects the kinetics of coproantigens. Thus, challenge during acute fascioliasis favours the migration of the juvenile flukes from the primary infection to the bile ducts, and is responsible for the earlier presence of coproantigens in these animals. The possible relationship between coproantigen detection and T1 and T2 tegumentary antigens is discussed.

Animals↗

PubMed2002

Influence of age and breed on natural bovine fasciolosis in an endemic area (Galicia, NW Spain).

An analysis was undertaken of the effect of breed and age on bovine fasciolosis using antibody and antigen detection ELISAs. A total of 84.3% of the 1284 serum samples examined had positive antibody values and 20.4% exhibited antigenaemia. The seroprevalence of antibodies in crossbred cattle was higher than that in autochthonous Rubia Gallega, Friesian or Brown Swiss cows. The highest percentage antigenaemia occurred in the Brown Swiss cattle, but the breed differences were not statistically significant. Cattle aged 3-5 years had the highest antibody and circulating antigen prevalence and the age differences were significant. It was concluded that the apparent influence of breed was probably closely associated with the husbandry system. The autochthonous Rubia Gallega may be better adapted to fasciolosis as its percentage of antigenaemia was the lowest.

Aging↗

PubMed2001

Effect of fasciolicides on the antigenaemia in sheep naturally infected with Fasciola hepatica.

A study was developed to evaluate the influence of triclabendazole (Fasinex) and netobimin (Hapasil) the antigenaemia in sheep naturally infected with Fasciola hepatica during 16 weeks. A sandwich-ELISA (enzyme-linked immunosorbent assay) using a rabbit polyclonal IgG antibody to F. hepatica antigens was employed and the data obtained were compared to those from coprological and indirect-ELISA techniques. Triclabendazole reduced the values of circulating antigens at weeks 2-4 post-treatment and faecal output at weeks 2-8 post-treatment, but antibodies showed positive values until the end of the study. Netobimin did not reduce circulating antigens of the trematode nor egg-excretion; and IgG antibodies did not decrease throughout the study.

Animals↗

PubMed2000

Use of a sandwich-enzyme-linked immunosorbent assay (SEA) for the diagnosis of natural Fasciola hepatica infection in cattle from Galicia (NW Spain).

An indirect-enzyme immune-linked immunosorbent assay (IEA) was compared to a sandwich-enzyme-linked immunosorbent assay (SEA) to diagnose fasciolosis in naturally infected cattle. By means of a rabbit polyclonal IgG antibody to F. hepatica antigens, captured circulating antigens were detected by an SEA technique. A total of 85.1% of the samples examined was considered positive by using the IEA-test, whereas this percentage was of 37.3% by the SEA test. Using the two enzymatic probes, only the 38.3% resulted positive to both immunoassay probes. Our data indicate that circulating antigen detection assay in combination with results of antibody detection may offer a more reliable diagnostic technique than classic coprologic ones, with results very appropriate for epidemiologic studies carried out on a wide area.

Animals↗

PubMed1999

Subclass profile of specific IgG antibodies in rats challenged during acute and chronic primary infection with Fasciola hepatica.

The influence of a previous infection (acute and chronic) on the kinetics of the immune humoral response in rats challenged with Fasciola hepatica was studied. Two infected groups were reinfected at different times--one, at 4 weeks after primary infection (w.a.p.i.); and the other, at 11 w.a.p.i. Signs of reinfection were observed in the two challenged groups as evidenced by an increment in glutamate dehydrogenase and gamma-glutamyl transpeptidase activity after secondary infection. IgG subclass (IgG1, IgG2a, IgG2b, IgG2c) responses to F. hepatica excretory/secretory products (FhESP) differed, depending on the time of challenge infection, but no difference was observed between the reinfected groups. A predominance of the IgG1 subclass was noted in the group challenged at 4 w.a.p.i., and IgG2b and IgG2c were prominent in the group reinfected at 11 w.a.p.i. These results indicate that the presence of juvenile or adult flukes in the liver at the time of challenge seems to influence the immune response to a secondary infection.

Acute Disease↗

PubMed1998

IgG isotype specific immune response in rats infected with Fasciola hepatica.

Antibody responses (IgG1, IgG2a, IgG2b, and IgG2c subclasses) against Fasciola hepatica L. in rats infected with metacercariae were analysed by ELISA. Animals of group 1 (R-1) remained infected throughout 21 weeks, and rats of group 2 (R-2) received a single oral dose of triclabendazole (Fasinex 10%, Ciba-Geigy) at 4 weeks after infection. Group C (R-C) consisted of rats left intact which served as uninfected controls. All IgG subclasses increased during the first weeks after infection, but when triclabendazole was administered IgG1 and IgG2b diminished markedly. IgG2c showed a different profile to the other antibodies evaluated, increasing earliest and decreasing profoundly from the 9-11th week after infection (w.a.i). The infected-untreated rats produced higher titres of antibodies than the rats of R-2, and these differences were statistically significant (p < 0.05) in all subclasses evaluated except in IgG2a titres.

Animals↗

PubMed1998

Subclasses of IgG in different aged rats with fasciolosis.

The variations in antibody responses (total IgG and IgG1, IgG2a, IgG2b, and IgG2c subclasses) were studied in two groups of rats infected with metacercariae of the trematode Fasciola hepatica L. Animals of group 1 were 4 weeks old, and rats of group 2 were 13 weeks old. All IgG subclasses increased during the course of infection except IgG2c, which decreased. The younger rats reached more marked responses than the older, at least during the period of this trial. IgG1 and IgG2a antibodies reached the highest levels, and among these two, IgG2a response was slightly superior to IgG1.

Age Factors↗