Eosinophil cationic protein, specific IgE and IgG4 in human toxocariasis.

Among 67 French patients presenting a toxocaral infection, various demographic, environmental, clinical and laboratory parameters (blood eosinophil count, eosinophil cationic protein (ECP), serum total IgE, specific IgE against common inhalant allergens, specific IgE and IgG4 against Toxocara excretory-secretory antigens) were investigated. Correlation studies and logistic regression analyses were conducted, testing elevated levels of ECP, specific anti-Toxocara IgE or IgG4 as outcome variables An elevated ECP level was significantly associated with both cough and rhinitis, a high level of specific anti-Toxocara IgE with itchy rashes and possible atopic status, and an increase of specific anti-Toxocara IgG4 with rural residence.

Epidemiology of alveolar echinococcosis in southern Cantal, Auvergne region, France.

Alveolar echinococcosis (AE) is a helminth zoonosis which is encountered only in the northern hemisphere. In central France, the Auvergne region represents the most western and southern extension of this helminthiasis. In 1999, a human case of AE was diagnosed in the southern part of the Cantal department, where AE was supposed absent, and an epidemiological survey was subsequently carried out. The transmission of the zoonosis in the sylvatic and peridomestic definitive hosts was studied, as well as that in the rodent and human intermediate hosts. Eleven red foxes (Vulpes vulpes) were shot, and 50 fox faecal deposits were collected. Twelve farm dogs had their faeces taken by rectal touch, and four were checked after arecoline purgation. Optical detection of Echinococcus multilocularis worms was achieved on fox intestines after scraping, and also on dog stools after arecoline therapy. Coproantigen ELISA assay was performed for the 11 scraping products, for the 50 fox faeces, and for the 12 dog faecal samples. No adult AE agent was observed by microscopy, and the ELISA assay yielded positive results in one of 11 fox intestines, one of 50 fox faeces, and 2 of 12 dog faecal samples. Twenty-five small mammals were trapped, of which 19 were Arvicola terrestris water voles. One rodent liver exhibited a hepatic lesion consistent with AE. An epidemiological questionnaire was completed in 85 human volunteers, who were also serologically tested for AE. Only one (the case's husband) exhibited a Western-blotting pattern indicative of a low-grade AE infection. The results of this preliminary study suggested a slow AE extension to the south of Cantal department from the northern focus.

Comparative assessment of conventional PCR with multiplex real-time PCR using SYBR Green I detection for the molecular diagnosis of imported malaria.

For the diagnosis of imported malaria, optical or immunochromatographic methods are known to be less sensitive and less specific than PCR-based methods, which are conversely more complicated and time-consuming. An original strategy, based upon the sequential use of a multiplex competitive real-time PCR detecting Plasmodium falciparum or Plasmodium spp. infection, followed by, if necessary, a single real-time PCR for species identification, was therefore performed and then tested versus conventional PCR in routine conditions. Conventional PCR has been used since October 1999 in the Department of Parasitology, University Hospitals in Toulouse, as a 2nd line diagnostic method. Out of 183 patients tested, 48 were found to be harbouring a falciparum infection by conventional microscopy, 60 by conventional PCR and 60 by multiplex competitive real-time PCR. Nine further patients had a non-falciparum infection, and concordant species identifications were obtained by both conventional PCR and single real-time PCR. The major value of PCR-based methods, when compared to microscopical techniques, was to ascertain the negativity of a suspect sample. Moreover, real-time PCR allows simplification of the operating procedure, with a diagnosis being made within 2 h.

Immunodiagnosis of ocular toxocariasis using Western-blot for the detection of specific anti-Toxocara IgG and CAP for the measurement of specific anti-Toxocara IgE.

A prospective multicentric study was carried out to assess both the performance of Western-blot (WB) detecting specific anti-Toxocara IgG and that of CAP measuring specific IgE titre for the immunodiagnosis of ocular toxocariasis. For 14 outpatients presenting ophthalmic symptoms (choroiditis, chorioretinitis, papillar oedema, hyalitis, retinal detachment and/or uveitis), samples of serum and aqueous fluid (AF) were sent to the Department of Parasitology, University Hospitals, Toulouse, France. All patients but two tested positive with WB on the serum; 13 WB tests were performed on the AF, 12 of which were positive. The two patients who had a negative WB serum result tested positive for the AF. Specific IgE detection was considered as a complementary test of WB. Two patients showed a greater specific IgE titre in the AF than in the serum, and one had a positive result in the AF, but not in the serum. These six patients were considered as clear cases of ocular toxocariasis. Western-blot coupled with specific anti-Toxocara IgE detection appeared therefore to be an accurate procedure for the immunodiagnosis of ocular toxocariasis, provided the testing was simultaneously performed on the serum and AF.

One year's experience with the polymerase chain reaction as a routine method for the diagnosis of imported malaria.

Given the problems encountered in westernized countries with the laboratory diagnosis of malaria, namely sensitivity of the conventional methods and detection of mixed infections, a polymerase chain reaction (PCR)-based diagnosis has been developed and routinely used. The PCR used two sets of primers to simultaneously detect any infection due to the genus Plasmodium, or to the species P. falciparum. The PCR results were available within six hours. Five hundred twenty-nine patients were tested, of whom 136 were found positive by the PCR, and only 104 by the quantitative buffy coat (QBC) method. The 32 discrepancies were analyzed on the basis of the clinical data, and technical, molecular, and sequencing findings to ascertain the presence of Plasmodium DNA. The PCR-based diagnosis of malaria appeared to be a useful tool that was suitable as a second-line method when the results of conventional techniques were negative in patients presenting a syndromeconsistent with malaria, as well as yielding an accurate species identification.

Eosinophil cationic protein as a possible marker of active human Toxocara infection.

BACKGROUND: Human toxocariasis is a common, worldwide helminthozoonosis that may elicit syndromes including various allergy symptoms. The diagnosis relies upon specific serology. However, this parasitosis is often self-limiting, and many subjects have residual antibodies, thus making differential diagnosis quite difficult when blood eosinophilia, a commonly accepted criterion of active helminthiasis due to tissue-dwelling parasites, is lacking. METHODS AND RESULTS: We present a patient with chronic irritant cough displaying negative allergologic screening, normal blood eosinophilia, but positive toxocariasis immunodiagnosis. Therefore, this case presented the fortuitous association of an unexplained allergic picture with residual anti-Toxocara antibodies. In an attempt to distinguish between active and past toxocaral infection, the subject's level of eosinophil cationic protein (ECP) was assessed and then compared to those of four control groups, namely, healthy volunteers, subjects presenting anti-Toxocara residual antibodies, patients with various helminthiases, and patients with active toxocaral disease. Since the patient's ECP level was found to be sharply elevated, we hypothesized that viable Toxocara larvae were still present in the tissues, and the patient was given anthelmintic therapy. At the control checkup, the cough had waned and the ECP level had decreased to below the mean value observed in both healthy subjects and in subjects with past toxocaral infections. CONCLUSIONS: These data suggest, first, that patients presenting unexplained allergic syndromes should be checked for helminthiases, even if blood eosinophilia is lacking, and, second, in such subjects displaying positive toxocariasis immunodiagnosis, ECP assessment would be a useful marker to distinguish between active and past toxocaral disease.

Highlights of human toxocariasis.

Human toxocariasis is a helminthozoonosis due to the migration of Toxocara species larvae through human organism. Humans become infected by ingesting either embryonated eggs from soil (geophagia, pica), dirty hands or raw vegetables, or larvae from undercooked giblets. The diagnosis relies upon sensitive immunological methods (ELISA or western-blot) which use Toxocara excretory-secretory antigens. Seroprevalence is high in developed countries, especially in rural areas, and also in some tropical islands. The clinical spectrum of the disease comprises four syndromes, namely visceral larva migrans, ocular larva migrans, and the more recently recognized "common" (in adults) and "covert" (in children) pictures. Therapy of ocular toxocariasis is primarily based upon corticosteroids use, when visceral larva migrans and few cases of common or covert toxocariasis can be treated by anthelmintics whose the most efficient appeared to be diethylcarbamazine. When diagnosed, all of these syndromes require thorough prevention of recontamination (especially by deworming pets) and sanitary education.

[A case of external human ophthalmomyiasis by Oestrus ovis in Toulouse (France)]. / Un cas d'ophtalmomyiase externe humaine à Oestrus ovis L. à Toulouse (France).

We report a case of external human ophthalmomyiasis by OEstrus ovis was observed in a child living in southwestern France. The patient was contaminated on the playground of a school in a suburban village near Toulouse. Eleven first stage larvae were extracted from the eye. This case illustrates that contamination can occur in suburban areas of a large city remote from any cattle breeding zone.

[A new case of subcutaneous dirofilariasis]. / A propos d'un nouveau cas de dirofilariose sous-cutanée.

Authors describe another case of subcutaneous dirofilariasis due to Dirofilaria (Nochtiella) repens in France. A 26-year-old woman was infected while on vacation in Cap d'Agde on the Mediterranean coast. The patient presented with a subcutaneous nodule in the right subclavicular region. Examination of the nodule after surgical excision revealed the presence of a worm identified as an immature female Dirofilaria repens. Dirofilariasis is a rare anthroponotic disease encountered only in the Old World, particularly in Southeastern France including Corsica which has the second highest number of reported cases after Italy. Since man is a dead-end for the parasite, Dirofilaria repens does not mature and hence most human infections present as isolated subcutaneous nodules. Nodules are usually located in areas exposed to bites by the dipteres, i.e. the face (46 p. 100 of cases reported in the world) and the periocular and palpebral region (30 p. 100). Diagnosis is based mainly on morphological examination of the worm after surgical excision. However promising results in diagnosis of ocular and visceral forms of Dirofilaria repens and understanding of helminthiasis have been achieved thanks to progress in immunological techniques, i.e., ELISA and western blot, and DNA analysis based on polymerase chain reaction.