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Biomedical subjects

A Michault

Publications and source records attributed to A Michault.

At least 19 recordsLinked to original sources
PubMed2006

[Chikungunya infection in pregnancy: Evidence for intrauterine infection in pregnant women and vertical transmission in the parturient. Survey of the Reunion Island outbreak].

PURPOSE: Since February 2005, an outbreak of Chikungunya virus (CHIKV) infections occurred in Reunion Island. It is transmitted by the Aedes albopictus mosquito. Neonatal cases observations suggest possible fetal transmission during pregnancy. MATERIAL [corrected] AND METHODS. Observations made in 160 pregnant mothers infected by CHIKV between June 1, 2005 and February 28, 2006, in the south of Reunion island were recorded. RESULTS: Three of nine miscarriages before 22 weeks of gestation could be attributed to the virus. 3,829 births took place during this time. Among the 151 infected women, 118 were viremia negative at delivery, and none of the newborns showed any damage. Among the 33 with positive viremia at delivery, 16 newborns (48.5%) presented neonatal Chikungunya. DISCUSSION: Though fetal contamination risks appear to be rare before 22 weeks of gestation, they are potentially dangerous. After 22 weeks gestation, newborns infection occurs if the mother is viremia positive at delivery. Transplacental transmission is suspected, but the pathogenic mechanism remains unknown.

Abortion, Spontaneous↗
PubMed2005

[Antimicrobial resistance of Streptococcus pneumoniae strains isolated in the Reunion Island during 2004].

OBJECTIVE AND METHOD: Available data from the Southern Reunion Island Medical Group was processed to assess the evolution of Streptococcus pneumoniae resistance to antibiotics since 1994 when the first penicillin-non-susceptible S. pneumoniae (PNSSP) was identified. In addition, 249 strains, isolated between 1998 and 2004, were tested against telithromycin and moxifloxacin. RESULTS: Between 1994 and 2004, the percentage of PNSSP increased from 0 to 59.2%. Among PNSSP, 13.9% were resistant strains in 2004 with MICs<4 microg/ml. Before 2001 the rate of resistance to penicillin was superior to 50%. In 2004, 15.8 and 8.7% of the isolated strains were of decreased susceptibility to amoxicillin and cefotaxime respectively while none were resistant to either treatment. Other antibiotics followed the pattern of resistance to penicillin. Between 1998 and 2004, resistance to erythromycin decreased from 42.5 to 35.1%, from 35.1 to 22.8% for cyclins, from 18.8 to 8.8 for chloramphenicol, and from 38.3 to 12.3% for cotrimoxazole. All tested strains were susceptible to both telithromycin and moxifloxacin. CONCLUSION: Amoxicillin remains efficient for all strains isolated in the Reunion Island in 2004. The presence of strains with decreased susceptibility to third generation cephalosporins implies combination with vancomycin for empirical treatment of pneumococcal meningitis. Moxifloxacin can be used when using a fluoroquinolone is justified. Telithromycin is efficient even on strains resistant to erythromycin and consequently this molecule can be prescribed in the case of a required macrolide treatment.

Aza Compounds↗
PubMed2002

[Antibiotic resistance of Helicobacter pylori in Reunion Island: therapeutic consequences].

The aims of this paper were to assess resistance of Helicobacter pylori to antibiotics included in the so-called French triple regimens and to identify the possible causes of therapeutic failure in Reunion island. Antibiotic resistance was determined for 109 strains. All the strains were sensitive to amoxicillin and tetracycline, 93.6% were sensitive to ciprofloxacin, 92.7% to erythromycin and 60.6% to metronidazole. Fifty three patients who had previously tested positive for H. pylori received for one week regimen of amoxicillin (1 g bd), clarithromycin (0.5 g bd) and omeprazole (20 mg bd). Eradication rate after therapy was of 73.6%. Therapeutic failure was analysed for 9 patients using random amplified polymorphic DNA and the presence or not of antibiotic resistance. One cause of failure is clarithromycin resistance. These data show that triple therapy can be used in Reunion Island. In case of failure, sensitivity must be detected because the rate of resistance to metronidazole is over 30%.

Amoxicillin↗
PubMed2001

[Seasonal trends of respiratory syncytial virus infections on Réunion Island gathering data among hospitalized children].

Little is known about the epidemiology of respiratory syncytial virus (RSV) infections in tropical countries and in particular in tropical islands of the Indian Ocean. Our study reviewed all cases of RSV infections diagnosed among hospitalized children in the Hospital de Saint Pierre de la Réunion, from January 1993 to December 1999. 849 cases were identified of which 67.7% were infants under 6 months old. Most cases occurred from December to May (89% of all cases), showing a significant correlation with the hot and rainy season. These data confirm the previous studies and support the existence of seasonal trends of RSV infections in the tropics.

Child, Preschool↗
PubMed2000

[Prevalence of hepatitis A, B, C virus markers in Réunion (south hospital and Saint Pierre prison)].

We studied the prevalence of Hepatitis A, B, C in different groups in the population of the South of Reunion Island. The aims of this study were the following: to estimate the prevalence of Hepatitis C virus (HCV) (anti-HCV antibodies) and Hepatitis B virus (HBV) (anti-HBc, HBs Ag and anti-HBs) in a population of 1455 women, who delivered in the Centre hospitalier Sud Reunion (CHSR), to estimate the prevalence of these two viruses in a population selected for risk factors (100 prisoners), to estimate the prevalence of Hepatitis A in a group of 400 persons (aged 0 to 19) hospitalised in CHSR since 1st January 1998 (100 for each 5-year age bracket), to research risks factors in these populations and immunity. The overall prevalence of anti-HCV was 0.14% in pregnant women and risk factor associated was found in 28.9% of this population (2.9% history of transfusion, 0.21% drug users). In the group of prisoners seroprevalence was 2%, far below that of prisoners in France. Anti-HCV seroprevalence is weak in Reunion Island and very inferior to seroprevalence in the French population as in other Indian Ocean islands. This is due to the low risk of parenteral transmission. Anti-HBc was found in 90 serum samples from women (overall prevalence 6.35%) and of these 90 positive samples, 9 were positive for HBs Ag (overall prevalence 0.63%), 68 were positive for anti-HBs (4.81%) and 22 (1.54%) were anti-HBc isolated (without HBs Ag and anti-HBs). The overall prevalence of anti-HBs was 62.8%. In the population of 100 prisoners, 2 were HBs Ag positive, 10 anti-HBc positive (2 anti-HBc isolated, 2 associated with HBs Ag, 6 with anti-HBs). The prevalence of anti-HBs was 22%. The major risk factor observed in this population of prisoners was tattooing and/or piercing (46%). These results show that: Reunion island is an area of low endemicity for HBV virus. The measure of protective inoculation is well followed. i.v. drug abuse and previous transfusion are weak routes of transmission. In the group aged 0 to 19, overall prevalence of anti-HAV was 11.9% with the highest rate found among 15 to 19 year-olds (25%). Seroprevalence falls with socio-economic progress. At the present time, the endemic is intermediate in Reunion Island. Given immunity levels within the young population, there is a risk of outbreak. This risk is due to the conditions in Reunion Island, but also to people who travel to other Indian Ocean countries where endemicity is high. It is thus very important that a vaccination strategy be determined.

Adolescent↗
PubMed2000

[Bacteriological and epidemiological data on Streptococcus pneumoniae in the hospital of southern Reunion Island].

We studied the epidemiology of Streptococcus pneumoniae in southern Reunion Island from 1993 to 1998. Data were collected from the Centre hospitalier Sud Reunion. Incidence of pneumonia was calculated by applying published ratios to two different types of data (bacteriological, clinical). Survey of pneumococci showed that antimicrobial resistance of S. pneumoniae to penicillin G appeared in 1994 and reached high levels in 1998. We confirmed the increase of multiresistant strains among penicillin resistant S. pneumoniae. Serotyping the penicillin resistant S. pneumoniae has shown that these strains belonged to serogroups 9, 14, 19, 23. The MIC determined in PRP showed that imipenem was the most active agent among beta-lactamin antibiotics followed by ceftriaxone. Strains with high resistance to amoxicillin are rare. Annual incidence of meningitis was almost 0.4 per 100,000 inhabitants. Estimation of pneumonia incidence was between 44 and 78 per 100,000 inhabitants. Incidence in Reunion Island is twice to three times lower than the incidence in France. Death rate from pneumoniae (10%) is similar to that in France. In the course of the study, the number of isolated S. pneumoniae increased. Changing socio-economic conditions are probably associated with the emergence of PRP since 1994 and the increase in numbers of infections. Pneumococcal infections in Reunion Island are becoming a public health problem of the same importance as in France.

Adolescent↗
PubMed1999

Serologic and genetic characterization of HIV type 1 subtypes on Reunion Island.

The aim of this study was to determine the HIV subtypes present on Reunion Island, a French island located in the Indian Ocean, where the first case of AIDS was diagnosed in 1987. Paired sera and blood samples were collected between September 1996 and September 1997 from 53 HIV-1-positive patients. Subtyping was performed by serotyping with a previously described subtype-specific enzyme immunoassay (SSEIA) and by genotyping with the heteroduplex mobility assay (HMA). When samples gave uninterpretable results with either of the methods, or discordant results, the V3 env region was sequenced and genetic subtypes were determined by phylogenetic analysis. Genetic subtyping showed that 48 of 53 patients were infected with HIV-1 subtype B (90.5%). This high prevalence of subtype B on Reunion Island is probably due to the regular exchanges with metropolitan France. The other five patients were infected with subtype A (9.5%); they had been directly linked to African populations. Of the 48 subtype B samples, 44 (91.7%) were correctly subtyped by SSEIA and 43 (89.6%) by HMA. However, the SSEIA did not allow the subtyping of A strains in three of five patients. Thus, the SSEIA could be an alternative routine technique for screening subtype B versus nonsubtype B HIV-1 strains.

Amino Acid Sequence↗
PubMed1999

Serological diagnosis of human cysticercosis by use of recombinant antigens from Taenia solium cysticerci.

A Taenia solium metacestode cDNA expression library in the lambda ZAPII vector was screened with pooled sera from patients with neurocysticercosis. Sixty primary clones were identified and shown to belong to two classes. The clones NC-3 and NC-9 did not reveal any significant homologies to sequences deposited in the databases and were further characterized. Both recombinant antigens were expressed as glutathione S-transferase fusion proteins and applied for serological diagnosis of human cysticercosis. An enzyme-linked immunosorbent assay was established and evaluated with 27 serum samples of La Réunion and Madagascar patients with cysticercosis. Diagnosis in these patients was established with radiological and serological procedures. For antigen NC-3 a sensitivity of 96.3% and a specificity of 91.5% for the serodiagnosis were achieved. In contrast, the sensitivity of antigen NC-9 was only 33.3%.

Animals↗
PubMed1999

[Prevalence of hepatitis C virus infection in pregnant woman on the island of Réunion].

AIMS: The aim of this prospective study was to assess the prevalence of anti-hepatitis C virus antibodies in a population of pregnant women in Réunion. METHODS: Over a 6-month period, all blood samples of pregnant women who delivered at a hospital in the south of Réunion were tested with a third generation enzyme-linked immunoassay. In addition, risk factors for hepatitis C transmission were systematically looked for. RESULTS: Among the 1,455 women tested during this period, only 2 sera were found to be positive, resulting in a prevalence of 0.14%. One of these women had a history of intravenous drug use, whereas the other had no identified risk factor. This low prevalence was found to be associated with a low frequency of risk factors of C virus infection in this population: a history of transfusion and intravenous drug use was found in 2.9% and 0.21% of cases, respectively. CONCLUSIONS: The prevalence of hepatitis C virus infection is particularly low in Réunion. This low prevalence is explained by the rarity of risk factors for hepatitis C transmission in this region which is close to the African continent and has a similar high prevalence of hepatitis B virus infection.

Female↗
PubMed1998

[Insularity and epidemic risks in Réunion].

The risks of epidemics in Reunion island depend on determining or favourable factors. The determining factors, links in the epidemic chain, may or may not exist but they can be introduced from the outside. The risk of importing these factors is especially important when the exchanges with the epidemic zones are easy and frequent. Reunion island, at the moment exempt from certain pathologies such as malaria, dengue-fever and urinary Schistosomiasis, is a good example. However, if the presence of these determining factors is necessary, that is not enough in itself. Other factors come into play; in particular physical (leptospirosis) or socio-economic conditions (cysticercosis, intestinal parasitic diseases). The latter play a major role in the hygienic conditions and also in the research and prevention which are easier on an island.

Cysticercosis↗
PubMed1998

[Epidemiological surveillance of grippe and dengue. Réunion, 1996].

The local Welfare and Health Authorities together with the country council of Reunion Island set up a medical supervision network for influenza and dengue fever in March 1996. Influenza of which the spreading over the island has never been well-researched is anticipated by a vaccination campaign organised in an empirical way after a model from the mother country (France). Dengue fever of which one of the vectors is omnipresent on the island ranged in an epidemic way in 1978. The aim of this network based on watching doctors, the laboratories of the island as well as the Pasteur Institute of Madagascar, is to adapt the prevention (Flu) and alert the Health Authorities in case of epidemic (Dengue). The article shows the results of 1996 observation and touches on the future of this type of supervision in a tropical environment.

Dengue↗
PubMed1998

[Serologic studies of non-venereal treponematoses in infants in Niamey, Niger].

Though no longer reported by health centers, non-venereal treponematoses is still endemic in both arid (Bejel) and Sahelo-soudanian (Pian) areas of Niger. This study describes randomized TPHA testing carried out among children under 5 years of age living in three different sections of Niamey. Clinical examination was not performed before testing. In the overall sample of 183 children, the percent of positive tests was 12.0% with no difference according to place of residence or age. Only 3 of 37 children under the age of 12 months were seropositive Relative levels were too high to be dismissed as serological artifacts. The most likely explanation for the high antitreponemic antibodies is endemic syphilis, or Bejel, which is increasing in this region. Results in children under the age of 12 months suggest that congenital syphilis is uncommon.

Child, Preschool↗
PubMed1997

[The progress of malaria in sahelian eastern Niger. An ecological disaster zone].

The south eastern part of the Republic of Niger was ecologically damaged by the dryness since 1971. Rainfall decreased by 30 to 40% as compared to 1961-70 and lake Chad retreated 100 km to the south. Now it does not reach any more the Republic of Niger. Malaria studies have been carried out in urban and suburban places in Zinder and in the Diffa area at the extreme east. In Zinder parasitic indexes (PI) after the rainy season were around 30% to 10% according to the situation of the corner in respect with surface waters during the rains. In dry season the index fell to 3%. In Diffa in a part of the city at high risk because lining the Komadougou river, PI was only 6.7% in October after the rains. Before 1970 PI recorded in Niamey were up to 50%. In Diffa area they were of 49% in N'Guigmi and 32% in Bosso, ecologically similar to Diffa. Obviously there was a sharp decrease of malaria which could be due to the disappearance of An. funestus after 1970. It was one of the main malaria vectors. Its larvae were developing in pools remaining after the rains with heavy standing vegetation. These breeding sites have been destroyed by both dryness and human activities. Now the area has became hypoendemic and is suitable for epidemic because population has not much immunity. A surveillance system for epidemic control should be settle.

Animals↗
PubMed1997

[Eco-epidemiology of malaria in Niamey and in the river valley, the Republic of Niger, 1992-1995].

The Niger valley is an original ecosystem in the Sahelian belt. For more than 25 years it has been affected by dryness and rainfall decreased by more than 30% as compared to the period 1950-1960. Moreover the demography has sharply increased and the capital town Niamey grew by 10% a year. The Niger valley including Niamey has about 1 million inhabitants. Three sites have been selected to study the status of malaria and its evolution for the last 30 years: Niamey, Karma 40 km on the N.W. on the river and the nearby fossil valley of Fatay-Karma. In the sixties the malaria vectors were An. gambiae, An. arabiensis et An. funestus. The last species was no more harvested after 1970 because its breeding places have been destroyed on the combined action of dryness and human activities. In Niamey, parasite index was very low in the dry season but grew by 5 to 10 times during the rainy season to reach 50% in certain corners. The highest plasmodic index (PI) were recorded along the river banks where vectors are found all the year long. It decreases in the central part of the city and becomes very low in some peripheral suburban settlements. This situation is quite different of most of the cities of the area where prevalence decrease from outskirts to city centre. The serology confirms these points. In Karma, along the Niger and despite a perennial transmission, the PI removes low as well as the malaria antibodies, probably because of the self use of antimalarial drugs by the population. In Fatay-Karma the PI of 23.9% after the rainy season drops to 6% in the dry one. In data prior to 1970 the PI was over 60%, reaching 89% in young children of Niamey suburbs. Obviously it has strongly decreased. It is very likely that this is due partly to the disappearance of An. funestus after the drought.

Adolescent↗
PubMed1997

[Serological study of rickettsia infections in Niamey, Niger].

Rickettsioses is a possible alternative to presumptive diagnosis of malaria. A serologic study was carried out in 1994 to determine the prevalence of rickettsioses in children under 5 years of age from three different areas of Niamey, Niger. Indirect immunofluorescent assays using the micromethod were performed with antigens for Rickettsia conori, Rickettsia mooseri, and Coxiella burneti. Results were read from a positive threshold of 1/160 up to 1/640. Out of a randomized population of 177 children 35 were positive for at least one antigen: 17.5% for Rickettsia conori, 15.8% for Rickettsia mooseri, and 9.6% for Coxiella burneti. The incidence of positivity for Rickettsia mooseri and Coxiella burneti. was significantly higher in an area where contact between people and animals was particularly close. This high rate of positivity is in agreement with previous reports in other countries in West Africa and suggests that close contact between man and rickettsiae is common. Although dogs carry ticks in Niger, direct contact with Rickettsia conori is probably the most mode of transmission. Rodents like Cricetomys gambianus and Rattus norvegicus carry Rickettsia mooseri and goats and sheep which are often kept in the courtyards of buildings carry Coxiella burneti. The recently identified species Rickettsia africae could be transmitted by other vectors such as cattle ticks.

Animals↗