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F Simón

Publications and source records attributed to F Simón.

At least 37 records · Page 2Linked to original sources
PubMed1999

Human dirofilariasis in the European Union.

The dog parasites Dirofilaria immitis and D. (Nochtiella) repens, well known as zoonotic agents, are widely distributed in southern Europe. Although both species are canine parasites, infection with immature worms has been found in humans, who develop nodules, mainly in subcutaneous tissue or in lung parenchyma arising from branches of the pulmonary artery. In humans, the parasites do not usually reach the adult stage and microfilaremia is absent, as has been shown by diagnosis using invasive methods for removing the nodules. In this article, Antonio Muro, Claudio Genchi, Miguel Cordero and Fernando Simón review the current situation concerning the clinical and epidemiological aspects, immune response and diagnosis of human dirofilariases.

Adult↗
PubMed1999

Serological assays on eight cases of human dirofilariasis identified by morphology and DNA diagnostics.

Specimens of Dirofilaria sp. removed from eight Italian patients were identified as D. repens by morphology and confirmed as such by a PCR-based method of DNA analysis. Blood samples were also drawn from the patients so that two serological tests (ELISA and western blot), one based on the recognition of molecular markers recently identified in the somatic antigenic complex of D. repens, could be evaluated. The antigenic complex used in the ELISA only gave a weak sensitivity. However, the western-blot assays, based on the polypeptide molecular markers, were found to have greater sensitivity and should be useful in detecting human cases of dirofilariasis.

Animals↗
PubMed1998

Subconjunctival infection with Dirofilaria repens: serological confirmation of cure following surgery.

Cases of zoonotic dirofilariasis infection, caused by Dirofilaria repens, occur widely throughout European, African, Middle Eastern, and Asian countries. The reports of this infection in humans in Spain are limited, and we herein report the case of a 43-year-old man from Elche (Alicante), Spain, who was seen with acute hyperemic reactivity of the temporal limbus of the right eye. A large nematode was visualized on examination and the intact worm was surgically removed. The parasite was identified as a mature but infertile female D repens. The level of serum antibodies against D repens was monitored for 6 months after surgery using immunoenzymatic assays. Serological results confirmed, as expected, the presence of a single worm and the parasitological cure after the surgical removal of the parasite. To our knowledge, this is the fourth autochthonous case of D repens infecting humans in Spain and also the first autochthonous case of subconjunctival localization.

Adult↗
PubMed1998

Utility of antibodies against a 22 kD molecule of Dirofilaria immitis in the diagnosis of human pulmonary dirofilariasis.

To assess the characteristics of an ELISA test for the diagnosis of human pulmonary dirofilariasis, we studied the sera of 24 subjects with other helmintoses and of 37 patients suffering from non-parasitic focal lung diseases, comparing them with negative and positive sera. ELISA and Western blot with complete somatic antigen and ELISA with protein Di22 (specifically recognized in cases of lung dirofilariasis) were performed. With ELISA SA the false positive rate was 25% in cases with other parasitoses and 30% in cases with focal lung diseases. ELISA Di22 decreases this positivity levels. Only 2 cases with visceral larva migrans (8.3%) and a case with lung nodules metastatic from renal adenocarcinoma (2.7%) were positive. ELISA Di22 therefore greatly decreases the false positive rate of ELISA SA.

Aged↗
PubMed1997

Fasciola hepatica: vaccination of rabbits with native and recombinant antigens related to fatty acid binding proteins.

The current study was designed to compare the immunogenic and immunoprophylactic properties of native (nFh12) and recombinant (rFh15) antigens from Fasciola hepatica in rabbits infected with the fluke. Levels of specific anti-nFh12 and anti-rFh15 antibodies were significantly higher in the rabbits vaccinated twice compared with non-vaccinated infection controls. A reduction of 40% in worm burdens was found in rabbits immunized with nFh12 and infected 4 weeks after the second immunization. The recombinant vaccine induced lesser levels of protection than the native one, suggesting that both molecules may have slight differences either in immunogenicity or in their configuration. Further biochemical studies are required to define these differences. The mean length of flukes recovered was always smaller in all vaccinated rabbits. In addition, infected control rabbits had higher gamma glutamil transferase (GGT) levels than immunized rabbits. Lastly, gross anatomic observation always showed fewer liver lesions in all vaccinated rabbits than in controls. This finding clearly supports the possibility of vaccination regimes in fasciolosis.

Animals↗
PubMed1997

A preliminary assessment of the recombinant antigen PLA2 in the diagnosis of human dirofilariosis.

Two recombinant antigens (P22U and PLA2), cloned in a L4 Dirofilaria immitis cDNA library, were analyzed by Western-blot and ELISA to investigate their characteristics for the diagnosis of human dirofilariosis. P22U seems related to a Di22 native antigen useful for the diagnosis of pulmonary dirofilariosis, but it is unspecifically recognized by sera from patients with different parasitic and non parasitic pulmonary diseases. PLA2 is not related to Di22 but specifically reacts in Western-Blot and ELISA with sera from patients with subcutaneous dirofilariosis.

Antigens, Helminth↗
PubMed1997

Human humoral immune response to Dirofilaria species.

Dirofilaria immitis and D. repens, the agents of human pulmonary and subcutaneous dirofilariosis respectively, may coexist in areas of Southern Europe, and L3 and L4 of both species develop in subcutaneous tissue. Previous studies have shown that humans develop high levels of specific IgM, IgG and IgE anti-D. immitis. An antigen of approximately 22 kDa (Di22) is a marker of pulmonary dirofilariosis. In this work, we demonstrate that D. repens also induces IgG in infected humans. Polypeptides between 40 and 26 kDa from adult somatic antigenic complex of the later species, are specifically recognized by sera from individuals with subcutaneous dirofilariosis due to D. repens. These findings complement the previous studies on specific antigens for the serological diagnosis of pulmonary dirofilariosis.

Animals↗
PubMed1995

Evaluation of Dirofilaria immitis excretory/secretory products for seroepidemiological studies on human dirofilariosis.

The usefulness of excretory/secretory (E/S) products of adult Dirofilaria immitis for the diagnosis of human dirofilariosis was evaluated in 97 human sera using an ELISA and a Western Blot analysis with E/S antigens. Results of the ELISA analysis show that in healthy individuals from an endemic area seropositivity is high (22%). Immuno Blot analysis shows that the reaction pattern with E/S antigens differentiates healthy seropositives, which recognize a 43 kDa band, from patients with pulmonary dirofilariosis, which specifically recognize bands between 22-28 kDa.

Animals↗
PubMed1995

Serological diagnosis of subcutaneous dirofilariosis.

We present serological evidence that Dirofilaria immitis was the causative agent of subcutaneous nodules in two patients. ELISA and enzyme-linked immunoblot analysis showed that the two human sera had a reactivity pattern similar to that of D. immitis rabbit immune serum. The reaction pattern of the human sera was very different to that of Dirofilaria repens rabbit immune serum. In the light of our findings, the traditional view that subcutaneous filarial nodules are due to D. repens has to be revised.

Adult↗
PubMed1994

Evaluation of a 22 kDa Dirofilaria immitis antigen for the immunodiagnosis of human pulmonary dirofilariosis.

Human pulmonary dirofilariosis usually appears as a solitary pulmonary nodule. A 22 kDa antigen from Dirofilaria immitis adult worms specifically recognized by three sera from individuals diagnosed with pulmonary dirofilariosis was identified by enzyme-linked-immunoelectrotransfer blot. This antigen was purified by elution from acrylamide gels and evaluated in enzyme-linked immunoassay using sera from 92 patients with pulmonary dirofilariosis and other pulmonary and parasitic diseases. Its use in the diagnosis of human pulmonary dirofilariosis should be considered.

Animals↗
PubMed1994

[Human dirofilariasis: identification of a 44kD antigen recognized by IgM against Dirofilaria immitis].

BACKGROUND: Dirofilaria immitis is a nematode parasite of canids that, in endemic areas, can infect humans. The use of adult somatic antigens for the diagnosis of human dirofilariasis has the disadvantage of a low sensibility because of cross-reactivity with other helminths, specially with IgM antibodies. We describe in this work proteins of the adult somatic antigenic complex that are specifically recognized by human IgM. METHODS: Human sera with different characteristics were analyzed by an enzyme-linked immunosorbent assay (ELISA) for the detection of anti-D. immitis IgM seropositive individuals. Moreover, an enzyme-linked immuno-electro-transfer blot (EITB) was performed for the detection of polypeptides that specifically react with IgM anti-D. immitis. RESULTS: EITB analysis shows that 2 proteins of 44 and 18 kD are recognized by IgM in human sera from an endemic area with a high antibody titer against D. immitis measured by ELISA. Sera from a non-endemic area and from patients suffering from other parasitic and non-parasitic diseases did not recognize these antigens. CONCLUSIONS: We believe that the 44 kD protein could be a good marker of recent D. immitis infection.

Animals↗
PubMed1993

Anti-Dirofilaria immitis IgE: seroepidemiology and seasonal variation in an exposed human population.

The seroprevalence of seasonal variation of human anti-Dirofilaria immitis IgE levels were studied in an area where specific IgM and IgG had been previously investigated. An antibody capture ELISA assay was used to detect specific IgE. The IgE seroprevalence observed in the whole population was 12.6%. No specific IgE was detected in atopic individuals or in sera from people suffering other helminthiases. The distribution of the IgE anti-D. immitis seroprevalence by age groups did not show differences. Females had significantly higher levels than males. This isotype of immunoglobulin peaks in July, decreasing sharply in October, and persisting at a level similar to that of a non exposed population during the rest of the year. No specific IgE were detected in subjects with pulmonary alterations related to the parasite, suggesting a possible relationship between the clinico-radiological status and the type of immunoglobulin synthesized in subjects infected by D. immitis.

Adult↗
PubMed1993

Natural infection of dogs by influenza C virus: a serological survey in Spain.

Two seroepidemiological surveys carried out so far, one in Japan, the other in France, gave a strong indication that dogs may be naturally infected by influenza C virus, considered to be exclusively human until recently. In this work, 101 serum samples were collected during winter 1989/1990 from dogs in Castilla y León, Spain. Sera were tested for the presence of antibodies to influenza C virus by Hemagglutination Inhibition (HI) test. Using antibody absorption by staphylococcal protein A, we demonstrated the specificity of the results. Significant HI activity was found in 56.3% of the 101 tested sera and titres ranged from 25 to 200.

Animals↗
PubMed1992

Are transient pulmonary solitary nodules a common event in human dirofilariosis?

Infection by Dirofilaria immitis is a rare cause of solitary pulmonary nodule. We describe the second case of transitory pulmonary nodule found by us in the course of a case-finding study, the third one reported in the literature. The detection of cases of transient pulmonary dirofilariotic nodules suggests that human infection is more prevalent than usually thought, and that this kind of manifestation is frequent in human dirofilariosis. Greater awareness is warranted in endemic areas.

Aged↗
PubMed1992

Differential recognition of Dirofilaria immitis antigens by human IgG and IgM positive sera. Preliminary data based on EITB analysis.

Preliminary data are presented on the differential recognition of Dirofilaria immitis antigens by sera positive for IgG and IgM (detected by enzyme linked immunosorbent assay, ELISA) using the enzyme-linked immunoelectrotransfer technique (EITB). The sera were followed prospectively over a year to detect seasonal variations. IgG mainly recognized antigens with a molecular weight (MW) lower than 74 kDa, while IgM recognized those with a MW higher than 43 kDa. The antigens with MW between 74 and 61 kDa were recognized by both isotypes. In IgG positive sera all bands were recognized throughout the year, albeit more mildly in summer. For IgM it is noteworthy that antigens with a MW between 43 and 20 kDa were not recognized in spring. These data are in accordance with those obtained with ELISA in the seasonal follow-up of positive sera.

Animals↗