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Biomedical subjects

M Marjolet

Publications and source records attributed to M Marjolet.

At least 19 recordsLinked to original sources

Serological and molecular characterization of Mesoplasma seiffertii strains isolated from hematophagous dipterans in France.

Three strains of nonhelical mollicutes previously isolated in France from two different mosquitoes and one tabanid fly were designated strains Ar 2328 (isolated from Aedes detritus), Ar 2392 (isolated from Aedes caspius), and CP 13 (isolated from Chrysops pictus). All of these strains exhibited properties of the genus Mesoplasma, a recently described genus of non-sterol-requiring mollicutes isolated from plants and insects. The results of metabolism inhibition and growth inhibition tests revealed that these strains and Mesoplasma entomophilum TAC or Mesoplasma florum L1 were not serologically related, but all three dipteran strains reacted strongly with Mesoplasma seiffertii F7T (T = type strain) antibodies. Using metabolism inhibition and growth inhibition tests, we found that the dipteran strains were related to each other and to strain F7T but were not identical. We also found that they were able to multiply and persist in the central nervous systems of suckling mice inoculated intracerebrally, a property that makes their use as biological control agents for pest dipterans inadvisable. Scanning electron microscopy revealed marked differences in the morphologies of the colonies of the different strains on SP4 solid medium. The levels of DNA-DNA homology for strains Ar 2328, Ar 2392, CP 13, and F7T were more than 70%, indicating that these strains are closely related members of the same species, M. seiffertii. In addition, one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that each strain produced about 40 protein bands. This technique also revealed differences between strains. Using the coefficient of Smeath-Jacquart, we constructed a dendrogram that allowed us to estimate of the levels of relatedness of these four strains. The results which we obtained were confirmed by two-dimensional protein electrophoresis results.

Aedes↗

[Argas and arbovirus update].

At the opportunity of the recent discovery of a new Phlebovirus, Tunis virus, the authors discuss the importance of the genus Argas as for its potential role in the transmission of arboviruses: twelve species of Argas are known to carry about twenty viruses. The wide distribution of Argas reflexes hermanni prompt us to explain its position in the Argas reflexes "complex" group: this species seems to be more liable to infection by viruses. Some ecological and entomological data are added to facilitate its typing. The Tunisian specimens recollected are remarkable by the lack of seta n degree 5 on basis capituli.

Animals↗

[Prevalence of pulmonary tuberculosis and HIV infection in the district of Diré in Mali].

In 1990, a study was made in the district of Diré, North Mali in West Africa, to determine the prevalence of pulmonary tuberculosis and HIV infections in general population. From 1,814 subjects tested, 1.1% (n = 20) have active pulmonary tuberculosis and 0.2% (n = 4) were seropositive with HIV1 or HIV1 + 2. No relation was made between the two diseases.

Adolescent↗

Epidemiologic approach to human toxocariasis in western France.

Toxocara canis is a common parasite in puppies. The danger to human health has not been properly established. We estimated the current incidence of this pathogen in two western districts of France, Loire-Atlantique and Maine et Loire. Blood samples from 1836 eosino-philic patients were collected and tested by an enzyme-linked immunosorbent assay (ELISA) excretory-secretory Toxocara antigen test. We obtained positive results in 22% of the cases and highly positive results in 7%. The ELISA data seemed to be age-dependent, with older patients having more positive results (P < 0.0001). The interlaboratory distribution of positive test results was statistically significantly different (P < 0.0001), suggesting regional sources. The main clinical expressions of toxocariasis were: asthenia, gastric pain, and pulmonary disease. Individual and collective surveys of this zoonotic disease need to be carried out.

Animals↗

[Transmission of hepatitis B virus from mother to child in Bamako-Mali].

Results of a study about mother-infant transmission of hepatitis B virus (HBV) confirm the high degree of positivity of HBV markers in Bamako, Republic of Mali. Among 372 sera of mother-newborn pairs, seroprevalence of HBs Ag has been around 11% in mothers. The lack of anti HBc IgM in all sera agree probably with a relative old contamination. Pre-S2 epitope marker has been found in more than 70% of HBs Ag positive mothers and 50% of their children. Large discordance has been noted between the prevalence rate of this marker and the HBe Ag and viral DNA, other markers of HBV replication. Further studies are necessary for the clear understanding of HBV transmission systems in our country.

Adolescent↗

[Prevalence of hepatitis B virus in women of childbearing age in Mali].

A serological investigation on adult female in Mali show a high degree of positivity of hepatitis B virus (HBV) markers, of which 42% HBs Ag +. Only 6% exhibit active replication. The low prevalence of anti-HBs (+) with a high degree of anti-HB (+) explain a high incidence of infection with a low immune response to HBs antigen. The existence of anti-Delta (+) asymptomatic carriers is an additional support to a vaccination programme.

Adolescent↗

[Does Boutonneuse fever in France have equivalents outside the Mediterranean area?].

In western of France, outside of mediterranean spotted fever area, several sera from autochthonous patients were positive for the presence of anti-R. conori antibodies by indirect immunofluorescence test. What is it all about: authentic rickettsiosis or paraspecific seroreactions with other microorganisms? We discuss these hypothesis.

Arachnid Vectors↗

[Value and limits of serological methods: electrosyneresis and E.L.I.S.A. for the study of the prevalence of histoplasmosis in Mali].

The authors have looked for circulating antibodies on 168 subjects for the study of the prevalence of histoplasmosis in Mali. Two serologic systems were employed: with counter-immunoelectrophoresis precipitating bands were detected in 42% of sera, while 57% were positive with Enzyme-linked immunosorbent assay. E.L.I.S.A. appear less specific because many cross-reactions were observed with other diseases.

Antibodies↗

[Babesiasis, pediatric malaria: does confusion exist in Africa?].

The authors describe a case of febrile disease acquired by a nursling in Africa: was it induced by Pl. falciparum or by Babesia sp.? In spite of numerous microscopic and serological appraisals from veterinary and medical authorities, it is difficult to state definitively this subject, but it is more probably a babesiosis of canine or rodent origin.

Animals↗