Biomedical subjects
Publications and source records attributed to G Bigaignon.
We report serial MRI findings in a 58-year-old man with cervical cord involvement by Toxocara canis, in whom antihelminthic chemotherapy yielded improvement of the neurological deficits and cord lesions seen on MRI.
Different techniques for identifying Toxoplasma gondii were compared. PCR was used to amplify part of the major surface antigen P30 gene of T. gondii. Amplified-DNA detection with the DNA enzyme immunoassay (PCR-DEIA) was more sensitive than ethidium bromide staining after agarose gel electrophoresis and as sensitive as nested PCR. PCR-DEIA, using common enzyme-linked immunosorbent assay (ELISA) methods, avoids agarose gel electrophoresis for the identification of amplified products. T. gondii can also be detected with equal sensitivity in infected fibroblasts, but only after at least 8 days of cell culture. PCR-DEIA is thus recommended because of its sensitivity and convenience for detecting early parasitemia in the surveillance of toxoplasmosis among pregnant women and immunocompromised hosts. The courses of infection in mice infected with two strains of T. gondii were compared. Tachyzoites of the virulent strain T. gondii RH, killing the host in 4 days, were identified in urine specimens and blood samples of mice 24 to 94 h after inoculation but not in brains, but no antibodies were detected. After intraperitoneal inoculation with cysts of the low-level virulence Beverley strain of T. gondii, parasites were identified in blood samples 4 days later and up to 17 days (but not in urine specimens) and in the brain from day 6 through day 525. By ELISA, high antibody titers were found from day 11 to day 525, with parasitemia preceding the appearance of antibodies. The usefulness of PCR-DEIA tests in conjunction with the search for circulating antibodies for the early diagnosis of toxoplasmosis in humans is discussed.
The performance of Western blots (immunoblots) prepared with eight strains of Borrelia burgdorferi representing B. burgdorferi sensu stricto, B. garinii, and B. afzelii genospecies was tested with a panel of sera with various clinical presentations collected from eight geographic regions. European sera were generally more reactive to blots prepared with B. garinii or B. afzelii strain antigens, in particular B. garinii 20047 and B. afzelii VS461. North American sera were more reactive with B. burgdorferi sensu stricto strains. Our observation of significant differences in the levels of reactivity of some sera on Western blots of certain strains is potentially important for the development and implementation of generic interpretive criteria. Preferential reactivity of sera from patients with nerve and/or palsy symptoms to B. garinii strains and with cutaneous disease to B. afzelii strains was observed. On the basis of our results, we have concluded that strain 20047 is the best strain to use for the development of a generic Lyme borreliosis Western blot for Europe.
Lyme borreliosis is a multisystem disease caused by the tick-borne spirochaete Borrelia burgdorferi. In addition to causing human illness, borreliosis has been recorded in many species of mammals, including domestic animals which come into contact with the infected tick vector. This paper describes the first two cases to the authors' knowledge of Lyme borreliosis in dogs in Belgium. Both animals suffered recurrent lameness and general prostration. In addition, one of the dogs had recurrent paralysis of nerves V, VII, IX and X, leading to dysphagia and total bilateral paralysis of the mandibular muscles. This complication of Lyme borreliosis has been well documented in human pathology, but has not previously been recorded in the veterinary literature.
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Oligonucleotide primers based on Borrelia burgdorferi sensu lato ospA gene sequences have been designed for use in the PCR to type all (SL primers) or each (GI to GIII primers) of the B. burgdorferi sensu lato genospecies involved in Lyme disease. These genospecies-specific primers were then used in the PCR on 24 biological fluids collected from 18 neuroborreliosis patients. Among the samples tested, 20 contained DNA from Borrelia garinii, 11 contained DNA from B. burgdorferi sensu stricto, and 10 contained DNA from Borrelia afzelii. In toto, 10 patients appeared to have been infected by a single genospecies and 8 were infected by more than one Lyme disease-associated genospecies. Serum specimens from six patients were absorbed with heterologous antigens and tested by Western blotting (immunoblotting). In four cases, residual immunodetection revealed specific epitopes of genospecies also detected by PCR; in two of them, the concordant results indicated pluri-infection of the patients. In the other two cases, Western blotting showed specific antibodies for two genospecies of Borrelia, while PCR detected DNA from only one. In summary, the data underscored the relatively high prevalence of pluri-infections in Lyme disease and confirmed the association of B. garinii with neuroborreliosis.
The authors, in a forest in Brittany previously studied for several years, caught by flagging, each month from April 1992 to May 1993, nymphs of I. ricinus tick, and looked by indirect immunofluorescence, for B. burgdorferi infestation. An amount of 1,506 ticks was thus studied. Infestation frequency was varying from 0 per cent in January and February to 14.4 per cent in August. Standarding of tick collecting method allowed to establish, for each month, a tick, "availability" index, and, according to the spirochete infestation frequency, to do estimation of the risk level, for human visiting the concerned forest, of being infected by B. burgdorferi. Obtained results show that this risk is the highest in August, and quite non-existent in January and February.
An intrathecal synthesis of IgA has been reported in various neurological disorders. However, the frequency of its occurrence and the electrophoretic characteristics of the locally produced IgA remained a matter of controversy. We developed a sensitive immunoaffinity-mediated capillary blot technique for the detection of polyclonal and oligoclonal IgA in the CSF of 115 patients with various neurological disorders. Paired CSF and serum samples containing 50 ng IgA after appropriate dilutions were submitted to isoelectric focusing in agarose gels; IgA was then blotted onto a polyvinylidene difluoride sheet coated by an anti-IgA antiserum or by infectious antigens. The immunoblots were revealed by an alkaline phosphatase-conjugated anti-IgA antiserum. Only five samples displayed CSF-restricted oligoclonal IgA bands, including two out of 33 from MS patients. In herpetic encephalitis (n = 5) and varicella-zoster meningitis (n = 2), a strong intrathecal production of virus-specific IgA antibodies was detectable. In such cases, faint oligoclonal IgA antibodies were superimposed on a polyclonal background. A weak local production of anti-Borrelia burgdorferi IgA antibodies was present in two out of four cases of neuroborreliosis.
After two seizures, a 13 year-old boy experienced headache, fatigue and loss of appetite over a period of 3 weeks. There was a bilateral papilledema with normal visual acuity. CT and MRI disclosed two ischemic foci, that were interpreted as evidence of vasculitis. High serum levels of IgG and IgM antibodies specific to Borrelia burgdorferi, were present. The patient had attended an outdoor scout camp in a area, in south-east Belgium, known to be endemic for tick-born borreliosis. The clinical symptoms, the levels of the specific antibodies and the radiologic abnormalities responded dramatically to treatment. We believe that seizures in this case were related to cerebral vasculitis. This case confirms the extreme diversity of the neurological manifestations of Borreliosis.
Six children with leishmaniasis, aged 10 months to 10 years, were treated in the Paediatric Department. Four patients had visceral leishmaniasis (kala-azar): diagnosis was based on bone marrow examination and therapy consisted of a combination of Glucantime and Lomidine. The remaining two children had cutaneous leishmaniasis: diagnosis was made by skin biopsy and the patients were treated with Glucantime alone. In all children, serology was clearly positive at the time of the diagnosis and all patients improved. The only side effects were cough associated with fever in one child, and supraventricular premature beats in another one. They were ascribed to Glucantime, and proved reversible after discontinuation of the treatment.
In a recent report, we gave results of a 4 year consecutively survey (1987 to 1990) of the level of Ixodes ricinus nymphs infested by Borrelia burgdorferi in two forests of the western part of France. This brought us to conclude that there was a relative stability for this level in course of time. Results of this survey kept on in 1991 oblige us to partly modify our conclusion, on account of an important dropping of the tick infection frequency in one of the two forests, this perhaps in connection with a large observed decreasing of the micromammals populations (but not of ticks ones) due probably to an exceptional drought during all the 1990 year.
Oligonucleotide primers were used in the polymerase chain reaction assay to amplify specific DNA regions of the Borrelia burgdorferi 49-kb linear plasmid. One set of primers identifies a 442-bp DNA fragment in the OspA gene and a second pair of amplimers, a 176-bp DNA piece located in the OspB gene. The last set of primers, OspBpc3/pc4, outperformed the other pair in discriminating pathogenic North American or European isolates from related bacterial species, detected down to 4 spirochaetes, and was suitable for the identification of B. burgdorferi in biological samples, such as synovial and cerebrospinal fluids.
The authors followed, during 4 years consecutively, from 1987 to 1990, by immunofluorescence, the frequency of B. burgdorferi in an amount of 677 nymphs of I. ricinus tick, collected fasting by flagging in 2 forests in Brittany (France). Percentages obtained in each of these forests do not reveal significative differencies statistically and seem to show a relative stability, from one year to the following, during the considered period, of the infestation levels in ticks.
An enzyme-linked immunosorbent assay with larval stage antigen was used to measure the concentration of antibodies to Toxocara sp in 2206 human sera. The results led to the determination of the specificity of our method, the experimental cutoff estimation and the Toxocara sp seroprevalence in different human populations. The prevalence of canine toxocariasis in pet dogs and the associated environmental contamination were studied through examination of 107 faecal and 20 sand-pits samples for Toxocara sp eggs. Our immunological studies and environmental research revealed the existence of toxocariasis as a zoonotic disease in Belgium. We compare here our results with those found in the world literature: in spite of some surprising results, the environmental factors are important for toxocaral infection. The urban residence, the restricted number of playgrounds for children and areas for dogs, the socioecological status are preponderant in the spread of infection.
We have collected sera from 4053 patients of different parts of Belgium. Sera were randomly selected whatever the kind of pathology. Anti-Helicobacter (Campylobacter) pylori IgG were determined with an ELISA technique using whole formalized bacteria. The results suggest that the mean antibody titres differ between various areas, with an overall higher prevalence in the north-western part of the country.
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Lyme disease is a multi-systemic infection caused by the spirochaete Borrelia burgdorferi: this bacterium, discovered in 1982 in the United States, is mainly transmitted by a tick bite, Ixodes ricinus in Europe. In Belgium, a first seroepidemiological study of 3 years has revealed 190 patients and the whole spectrum of clinical pictures was observed, including the early stage of this infection in the skin (erythema chronicum migrans), neurological involvement and arthritis. The Lyme borreliosis is endemic in our country: the incidence ranges from low near the coast to high in the south-eastern part of Belgium.
A case of insect bite with a peculiar evolution is presented. The simultaneous inoculation of Borrelia burgdorferi and the treatment are discussed.