Biomedical subjects

I Navarrete

Publications and source records attributed to I Navarrete.

At least 19 recordsLinked to original sources

PubMed2005

Epidemiology of Oestrus ovis (Linneo, 1761) infestation in goats in Spain.

This survey was conducted to determine the chronobiology and seroprevalence of nasal bot infestation (Oestrus ovis) in Spain and to identify the risk factors associated with this disease in caprine herds. A total of 1590 sera from adult goats were collected at random on 175 farms in southwestern Spain. Sera were tested by ELISA, using crude protein from second stage larvae as antigen. The mean seroprevalence was 46.04% and mean percentage of optical densities was 41.83. These data indicate a high prevalence of this parasite in the investigated areas. The serological survey revealed that goats managed at higher altitudes, at meridians latitudes and on farms with small herds had a smaller probability of infestation. Eighty goat heads, obtained from abattoirs in the central region of Spain, were collected and examined for nasal botflies from February to October 2002. O. ovis larval stages were recovered from the nasal-sinus cavities of 23 goats, reaching a prevalence of 34.94%. The mean larval burden was 3.9 larvae per infested head. No first instars were found during February and March, when the second instar reached its larger count. The third instar was observed in very small number during the whole period of study, with one peak occurring in July--August. These data show the existence of a favourable period for the development of larval instars of O. ovis in goats that starts in February and finishes in September.

Animals↗

PubMed2005

Analysis of larval antigens of Oestrus ovis for the diagnosis of oestrosis by enzyme-linked immunosorbent assay.

A serodiagnostic test for the diagnosis of infestation by the sheep nasal bot fly, Oestrus ovis (Linné) was examined. The enzyme-linked immunosorbent assay (ELISA) technique was used to analyze and compare the production of immunoglobulin G (IgG) antibodies against excretory-secretory products (ESP) and crude extract (CE) antigens from all the different larval stages of O. ovis in the sera of 276 adult sheep sampled in summer (n = 135) and winter (n = 141). ESP from first stage larvae was the most sensitive, coating antigen in winter and ESP from second stage larvae during summer. The most specific values were obtained by ESP against L1 in winter and by CE against L3 in summer. These results show that the stage of larval development has a significant impact on the humoral immune response over the course of a season. A significant correlation (P < 0.001) was found between the number of O. ovis larvae and the serum antibody levels using all differents antigens, except L3 CE. In Spain, where a long favourable period exists for the evolution and development of the different stage larvae between March and November, the ELISA test using L1 ESP antigen during winter and L2 ESP antigen in summer may be used for ovine oestrosis immunodiagnosis.

Animals↗

PubMed2004

Evidence of interaction between Ascaris suum and Metastrongylus apri in experimentally infected pigs.

A study has been carried out with the aim to determine possible interactions between Ascaris suum and Metastrongylus apri under experimentally infected pigs. Twenty-eight Iberian pigs were allocated into four groups. Group 1 was inoculated with 5000 infective A. suum eggs; group 2 received concurrently 5000 infective A. suum eggs and 5000 infective M. apri larvae; group 3 received 5000 infective M. apri larvae; group 4 served as uninfected controls. In each group, pigs were necropsied on day 7 (n = 4) and day 28 (n = 3) post-infection (p.i.). Pigs with single M. apri infections showed earlier and more severe respiratory symptoms compared to pigs with mixed infection, while no clinical signs were observed in pigs single infected with A. suum. Mean burdens of immature A. suum and immature and adult M. apri were reduced in pigs with concomitant infection both on day 7 and 28 p.i., respectively. In contrast, the number of white spots was significantly increased on day 7 in pigs with mixed infection. In addition, pigs of group 1 showed the highest eosinophil levels in blood compared to pigs in groups 2 (intermediate levels) and 3 (moderate levels). The results suggest an antagonistic interaction between A. suum and M. apri in concomitantly infected pigs.

Animals↗

PubMed2004

Presence of immunoglobulins and antigens in serum, lung and small intestine in Ascaris suum infected and immunised pigs.

The immunodetection of local Ascaris suum antigens and local and systemic antibodies were analysed in pigs reinfected with eggs or immunized with the 14, 42 and 97 kilodalton (kDa) fractions from A. suum. Twenty-one Iberian pigs were divided in 7 groups of 3 pigs. Groups 1 and 2 were uninfected and challenge control groups, respectively. Groups 3 and 4 were infected weekly with increasing doses of A. suum eggs and Group 4 was additionally treated with pyrantel pamoate. Groups 5, 6 and 7 were immunised with the 14, 42 or 97 kDa fractions from adult worms, respectively. Groups 2-7 were challenged with 10,000 infective eggs. Animals of Groups 3 and 4 showed a pulmonary granulomatous reaction with moderate number of eosinophils and leukocytes, while Groups 5-7 presented higher number of cells, especially in animals immunized with the 42 kDa fraction. These immunized groups presented abundant deposition of Ascaris body fluid (BF) and body wall (BW) antigens as well as the 14 and 42 kDa fractions in the pulmonary and intestinal tissues, while lower deposition of antigens was observed in animals of Groups 3 and 4. The immunized pigs of Groups 5 and 6 showed the highest systemic IgG titres in serum and these antibodies were negatively correlated with the number of larvae recovered in the lungs, suggesting that the IgG response may have a protective function against the ascariosis. The highest concentrations of IgA-bearing cells were observed in animals of Groups 3 and 4 compared to the immunised pigs (Groups 5-7), suggesting that local IgA production may be involved in the protection against migrating larvae. The main localisations of IgA-bearing cells were the bronchial and peribronchial areas of lungs and the lamina propia of duodenum. Low numbers of local IgG-bearing cells were observed in all animals and no IgM-bearing cells were detected in the local tissues.

Animals↗

PubMed2003

Seasonal variations in the larval burden distribution of Oestrus ovis in sheep in the southwest of Spain.

A chronobiological study of oestrosis was conducted for larval instars of Oestrus ovis from November 2000 to September 2002 with the examination of 477 adult sheep of the southwest region of Spain. Skulls from slaughtered sheep were examined and the different O. ovis larval stages (L1, L2, L3) were recovered from the nasal-sinus cavities. O. ovis larvae were detected in 339 sheep, reaching a prevalence of 71.1%. Only one farm was free of infested sheep indicating a prevalence of the 97.91% among studied flocks. The mean larval burden was 18.54 larvae per infested head during the coldest months in the southwest of Spain when the larval burden reached its highest levels, especially of the first larval stage (L1). However, the maximum percentage of L1 coincided with the minimum percentage of the second larval stage (L2). The third larval stage (L3) was observed in relatively low levels during the entered study period, but two peaks occurred in April-May and in September-October. During the 2 years of sampling, all the different larval stages were simultaneously recovered throughout the year, indicating the existence of a long favourable period for the evolution and development of the larval instars, which would start between February and March and finishing in November.

Animals↗

PubMed2003

Immunohistochemical distribution of antigens in liver of infected and immunized pigs with Ascaris suum.

In the present work, we carry out an immunopathological study of the swine ascariosis, under different conditions (control, infection and immunization). Twenty-one Iberian pigs were used and divided in seven groups. Groups 1 and 2 were the uninfected and challenged controls, respectively. Groups 3 and 4 were weakly infected with increasing doses of Ascaris suum eggs and treated with pyrantel (Group 4). Groups 5-7 were immunized with 14, 42 and 97 kDa proteins from the parasite, respectively. Groups 2-7 were challenged with 10,000 infective eggs 7 days before the sacrifice. The focal parasitic granulomata with eosinophils and lymphocytes were the main histopathological lesions in the liver of reinfected pigs, while more marked cellular infiltrate and abundant connective tissue were seen in the livers of immunized animals. There were important deposits of antigens in the livers of immunized and infected pigs. Antigens were mainly located in the connective tissue, with positive staining detection of the somatic larvae antigen, the body wall from the adult worms and the 14-, 42- and 97-kDa proteins. However, cholangiols, biliary ducts and macrophages presented an immunohistochemical positive stain against excretory-secretory and somatic antigens from the larvae and the body fluid antigen from the adult parasite. The detection of A. suum antigens in the liver of infected pigs improves the diagnosis of swine ascariosis. It may be possible to apply these procedures for diagnosis of human ascariosis in liver biopsies since A. suum from swine have been previously used as a substitute for the study of the human parasite Ascaris lumbricoides.

Animals↗

PubMed2003

Specific systemic IgG1, IgG2 and IgM responses in pigs immunized with infective eggs or selected antigens of Ascaris suum.

A total of 35 pigs aged 15 weeks old, and 21 pigs aged 8 weeks old were divided into 7 groups. Groups 1 and 2 were uninfected and challenge control groups, respectively. Groups 3 and 4 were infected weekly with 6 increasing doses of Ascaris suum eggs, and group 4 was additionally treated with pyrantel. Groups 5, 6, and 7 were immunized weekly with the 14, 42, or 97 kDa fractions from adult worms, respectively. Animals of groups 2-7 were challenged with 10000 A. suum eggs 7 days after the last infection/immunization. Serum was sampled weekly and specific IgG1, IgG2, and IgM responses were measured. Pigs of groups 5, 6, and 7 showed high IgG1 and IgG2 responses especially against adult worms antigens, while infected groups had high IgG1 and IgM responses, especially against larva. The IgG1 responses were negatively correlated to the numbers of larvae in the lungs, and positively associated with the liver white spot numbers. There was a positive correlation between IgG2 and the numbers of white spots and lung larvae, while IgM was negatively correlated with these parasitological measures. These findings are discussed and it is suggested that acquired resistance against A. suum larvae is correlated with the induction of IgG1 and IgM, and not with IgG2, and that future vaccination protocols may focus on inducing the Th2 activity.

Animals↗

PubMed2003

Serological responses to Ascaris suum adult worm antigens in Iberian finisher pigs.

Adult Ascaris suum were dissected to obtain different worm components (body wall, body fluid, ovaries, uterus and oesophagus) which were used as antigens when testing 95 sera of naturally A. suum-infected Iberian pigs by enzyme-linked immunosorbent assay (ELISA) and Western blot (WB). Pigs with patent Ascaris infections had significantly lower ELISA optical density values than pigs without adult worms when using the body fluid and the body wall as antigens. A poor negative correlation was found between adult intestinal worm burden or eggs in faeces and specific antibody responses, measured by ELISA and WB using all antigens. By WB, the recognition of specific bands was variable, but three groups of bands with molecular weights of 97 kDa, 54-58 kDa and 42-44 kDa were generally recognized by sera from naturally infected pigs as well as from hyperimmunized pigs when using the five antigen extracts. The ELISA and WB techniques may be used for immunodiagnosis, using somatic adult worm antigens, to declare young pigs to be Ascaris-free but cannot be used for individual Ascaris-diagnosis in adult Iberian pigs.

Animals↗

PubMed2001

Meningeal leishmaniosis induced by Leishmania infantum in naturally infected dogs.

We report two cases of meningitis caused by Leishmania infantum in naturally infected dogs. In both of these dogs the typical phenotypic features of granulomatous meningitis were observed with important lympho-plasma-cellular infiltrates and the presence of large numbers of parasites inside and outside macrophages. The immunological study of the cerebrospinal fluid of both animals showed that a large number of protein bands were recognized by those fluids and that they were similar to the ones recognized by the sera from the same animals. To our knowledge, this is the first description of meningitis associated to leishmaniosis.

Animals↗

PubMed2001

Comparison of IgM, IgG1 and IgG2 responses to Trichinella spiralis and Trichinella britovi in swine.

Pigs infected with T. spiralis and T. britovi were followed by double (IgG) and triple antibody ELISA (IgG1, IgG2 and IgM) during a 12-week-period. Specific IgG and IgG1 responses were similar and showed a significant relation with the infecting doses and intensity of infection. Response to T. britovi was slightly lower than in groups infected with the same dose of T. spiralis. IgG2 response was weak and almost undetectable in the lowest infected pigs, but relationship with the intensity of infection was unclear. IgM antibodies showed rapid but transient increases, generally simultaneous to peaks of IgG response.

Animals↗

PubMed2000

Efficacy of doramectin against naturally acquired nematode infection in Iberian swine.

Studies were carried out to determine the therapeutic efficacy of doramectin, administered intramuscularly at a dose of 300 microg/kg live weight, against naturally acquired helminths of extensively farmed Iberian pigs. The first study (slaughter study) evaluated, through necropsy of the study animals, the product's efficacy against gastrointestinal and pulmonary nematodes (Ascaris suum, Oesophagostomum dentatum and Metastrongylus sp.) whilst the second, faecal egg count reduction study, (FECR study) evaluated the drug's efficacy only against gastrointestinal helminths (A. suum, Trichuris suis and Oesophagostomum sp.). The first study used 20 animals divided into two equal groups of 10 on the basis of body weight and faecal egg count. One group constituted saline treated controls and the other was doramectin treated. On Day 14 post treatment half of the animals in each group were necropsied and the number of parasites present counted. On Day 15 the remaining half of each group underwent the same procedure. The second study was carried out with 40 animals divided equally into two groups of 20. This study determined the effect of doramectin treatment on faecal egg counts as an indicator of parasite burden. The first study demonstrated an efficacy of 100% against adult Metastrongylus sp. and A. suum, whilst the efficacy against O.dentatum was 96.3%. The second study indicated that at Day 21 post treatment there was a 100% reduction in egg counts in faeces in comparison to untreated controls.

Animals↗

PubMed2000

Experimental bovine hypodermosis in Spain.

An experimental survey was carried out in western Spain to investigate both the chronobiology of Hypoderma spp. and the immunoresponse of their bovine hosts. This study was initiated with a new system of obtaining Hypoderma spp. larvae directly from their host, including the eclosion of adults from their pupae, infestation under natural but controlled conditions, and confirmation of the resulting infection. This survey was carried out over 2 cattle grub seasons; it was possible to infest and reinfest the experimental animals and to monitor them by both parasitological methods and by an enzyme-linked immunosorbent assay. This method permitted the evaluation of the development of anti-Hypoderma antibodies during the experiment. The experimental design also enabled us to establish the period of detectable H. lineatum infection to be from December until the end of April with the largest number of warbles observed during March and April. After a pupal period of < 30 d, adults were seen in April and May. Hypoderma bovis (de Geer) showed a delay of 2 m.o. relative to H. lineatum (de Villiers). This study reports a completed biological life cycle of Hypoderma spp. under controlled conditions in both natural and experimental environments.

Animals↗

PubMed2000

Sylvatic trichinellosis in southwestern Spain.

The epidemiology of Trichinella spp. in their main sylvatic hosts, wild boar (Sus scrofa ferus and red fox (Vulpes vulpes), in Extremadura (southwestern Spain) was studied. We examined 88 Trichinella spp.-positive wild boar muscle-tissue samples from a total of 29,333 killed animals, referred to the Veterinary Parasitology Department (University of Extremadura, Spain) by the Extremadura Veterinary Service. Additionally, 227 red foxes killed during the hunting season and thus not subject to veterinary controls were examined for trichinellosis. Trichinella spp. larvae were found in six (3%) of the red foxes. All samples were examined using direct diagnostic techniques, including trichinoscopy and artificial digestion. The mean intensity of infection was 74.8 larvae/g (LPG) of muscle tissue in wild boars, compared to 30.6 LPG in foxes. Trichinella spiralis (sensu stricto) predominated over T. britovi in wild boars. Random amplified polymorphic DNA (RAPD) and alloenzyme typing showed that 74% of infected wild boars had only T. spiralis, 21% had only T. britovi, and 5% showed mixed infections. In contrast, 33% of infected foxes were infected only with T. spiralis, while 67% had T. britovi, suggesting a clear predominance of the latter in foxes. We suspect the existence of a paranthropic or sylvatic cycle in large areas of this region; given the ease of transfer between sylvatic and domestic or semi-domestic animals, this implies a high epidemiological risk.

Animals↗

PubMed1999

Analysis of the humoral immune response against total and recombinant antigens of Leishmania infantum: correlation with disease progression in canine experimental leishmaniasis.

Leishmaniasis by Leishmania infantum in the Mediterranean Basin constitutes an important problem in both human and veterinary medicine. Based in both the importance of canids as reservoirs for the human disease and the fact that the canine disease may be an excellent model for the human condition, the present work has been conducted to analyze clinical and immune mechanisms associated with canine experimental leishmaniasis. Six-month-old mixed-breed dogs were intravenously infected with L. infantum promastigotes and the infection course was monitored along a 343 days-period. On day 75 post-infection (p.i.), amastigotes were observed in the lymph nodes of all dogs. The analysis of the humoral response against total L. infantum antigens by both ELISA and Western blotting evidenced a correlation between the levels of IgG isotypes (IgG1 and IgG2) and disease progression. It was observed that in those animals showing either a regressive or an oligosymptomatic form of the disease, the anti-Leishmania IgG1 antibodies were undetectable whereas those animals developing active disease showed high levels of anti-Leishmania IgG1 antibodies. Additionally, the time-course of antibody production against L. infantum recombinant antigens in the experimentally infected dogs has been analyzed. The present data suggest that reactivity against the heat-shock protein 70 (HSP70) may be used as diagnostic marker of early steps of infection, and that the appearance of anti-histone antibodies is associated with progression of infection to disease status.

Animals↗

PubMed1999

Influence of infection intensity on predilection sites in swine trichinellosis.

The muscular distribution of Trichinella spiralis or T. britovi was studied by digestion in 59 experimentally infected pigs and seven wild boars. Crus muscle was the predilection site in 89.3% of 28 heavily infected swine with 146-3634 larvae per gram (lpg), but in 51.6% of middle to light infections (0.005-59 lpg) the basis of the tongue showed higher larval densities than the crus muscle. The basis of the tongue was also the predilection site in 71.4% of wild boars. Highest counts in other muscles were found only in lightly infected pigs. The influence of intensity of infection, host species, and Trichinella species on muscle distribution is discussed.

Animals↗

PubMed1998

Method for collecting Hypoderma spp. (Diptera: Oestridae) larvae from cattle.

A new method for collecting 3rd-instar Hypoderma lineatum (Villers) and Hypoderma bovis (L.) is described. A procedure for carrying out chronobiological and other studies involving the life cycle of these flies is included. The larvae are collected from cattle using a dressing made of a circle of cardboard attached to a piece of tulle similar in color to the coat of the animal. These small cloth cages were attached to the animal skin with fast-drying contact glue wherever the swellings produced by 2nd- or 3rd-instar Hypoderma spp. had been previously detected. Each animal was inspected daily to detect the appearance of new larvae. This procedure allows the collection of each emerged larva without contact with other larvae and avoids friction of the cloth cages or dressing with the larvae, thus reducing larval death and increasing viability of the parasite.

Animals↗

PubMed1997

Evidence of potential gene flow in Trichinella spiralis and in Trichinella britovi in nature.

During a study on the epidemiology of trichinellosis in Spain, 91 animals and 9 samples of sausages homemade with pork were found positive for Trichinella. Parasite identification at the species level was carried out by the polymerase chain reaction with a random primer on single muscle larvae. Seventy-one animals harbored Trichinella spiralis (17 domestic pigs, 53 wild boars, 1 fox), and 17 were infected with Trichinella britovi (1 domestic pig, 13 wild boars, 3 foxes). Sausages were infected with T. spiralis. Three wild boars (3.3% of infected animals) harbored both species. The presence of both T. spiralis and T. britovi in the same host suggests that infections with 2 isolates of the same species can also occur, permitting the gene flow within the species.

Animals↗

PubMed1997

Deer hypodermosis.

Hypodermyiasis is a common myiasis which affects a wide variety of deer species in many parts of the world. In this article a great review of the disease is made, treating the different species of flies that cause the myiasis in the different species of hosts. Biologies of deer and flies are also studied, with special dedication to the chronobiology of the life cycle of the parasite. Prevalence and intensity of parasitization in many parts of Europe are recorded like expression of the importance of hypodermyiasis in deer. Finally, some remarks about treatment and control are included.

Animal Husbandry↗