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C Chastel

Publications and source records attributed to C Chastel.

At least 55 records · Page 3Linked to original sources
PubMed1994

[Pathogen role of coronavirus in pediatric intensive care: retrospective analysis of 19 positive samples with indirect immunofluorescence].

BACKGROUND: Coronaviruses (CV) are ARN-containing agents that are responsible for mild upper respiratory tract infections in adults and children. Their pathogenicity in neonates is not wellknown. POPULATION AND METHODS: Eighty five samples of tracheal or nasopharyngeal secretions were obtained from January to October 1991 from 53 children (29 less than 1 month of age; 19 from 1 month to 1 year; five older than 1 year). They were examined for respiratory syncytial virus, adenovirus, myxovirus influenza and parainfluenza and coronavirus by immunofluorescence (IF). RESULTS: Nineteen samples from nine newborns and three infants were positive for coronavirus. The mean birth weight of the nine neonates was 2100 +/- 840 g; their mean gestational age was 34 +/- 5 weeks and their mean age at diagnosis was 21 +/- 9 days. Apnea and bradycardia were the main symptoms in this group. Blood C-reactive protein was not elevated and blood cultures were sterile. One infant was admitted for near-miss; the two others were admitted at birth because they suffered from chronic lung disease (pulmonary hypoplasia and bronchopulmonary dysplasia). An acute episode of pulmonary deterioration occurred at the time of coronavirus infection. Both died one at 4 months and the other at 10 months. CONCLUSION: Coronaviruses seem to be responsible for respiratory tract infections in hospitalized neonates and chronically ventilated infants.

Apnea↗
PubMed1994

[A serological survey regarding Flaviviridae infections on the island of Réunion (1971-1989)].

Serological prevalence of Flaviviridae was studied on Reunion Island by testing 2,507 human sera from a randomised sample. Each serum was tested against 5 viruses (yellow fever, dengue type 1 and 2, West Nile and Wesselsbron) using haemagglutination inhibition test: 42.68% of human sera were found positive. The multivalent reactions represent practically three fourths of the positive ones. A severe dengue type 2 outbreak on the island in 1977-1978 and the possible circulation of a Flavivirus may explain these data. Among the tested subjects, positivity frequencies vary according to their age and their living surrounding. These results were compared with those of a previous serosurvey performed in 1971 and showed an important increase in the serological prevalence largely explainable by the 1977-1978 epidemic.

Adolescent↗
PubMed1993

Evaluation of mechanical transmission of HIV by the African soft tick, Ornithodoros moubata.

OBJECTIVES: To assess the ability of the African Hut Tampan, Ornithodoros moubata, to mechanically transmit HIV-1 and to re-appraise HIV-1 infectivity in an arthropod cell line at 28 and 35 degrees C. DESIGN: To evaluate HIV-1 transmission by O. moubata, as determined by HIV-1 survival, 'blood-meal' size and interval between feeds, various tick developmental stages were allowed to feed on a heavily infected lymphoblast-rich blood-meal containing HIV-1BRU in an in vitro feeding chamber. METHODS: Blood-meal regurgitation was evaluated using 51Cr-labelled human erythrocytes, and human lymphoblast survival in ticks using Trypan blue. HIV-1 survival in ticks was evaluated by reverse transcriptase activity in tick homogenates cocultured with CEM lymphoblasts. Polymerase chain reaction and Southern blot analysis were used to detect proviral HIV-1 in arthropod cells in vitro. RESULTS: HIV-1BRU remained viable for up to 10 days with O. moubata adults. This is the longest recorded survival of HIV in an arthropod. In agreement with other studies. O. moubata regurgitated part of its previous blood-meal into the feeding lesion. Human CEM lymphoblasts partially survived for up to 7 days at 28 and 35 degrees C inside O. moubata's digestive tract. The blood-meal of adult female ticks was as high as 240 microliters (approximately 70 times more than a mosquito), while the most likely potential mechanical vectors (fourth- and fifth-stage nymphs) ingested an average of 39 microliters (maximum, 73 microliters), with some ticks re-feeding as early as 14 days postfeed in the absence of a moult. Shortcomings associated with the experimental protocol suggest that HIV survival within O. moubata may reach 14 days following natural infection, or that ticks might re-feed earlier. Although HIV-1BRU and HIV-1NDK were unable to replicate at 28 and 35 degrees C in CD4- Aedes albopictus C6/36 mosquito cells, HIV-1NDK was detected in its proviral form. CONCLUSIONS: Our investigations showed that mechanical transmission of HIV-1 by O. moubata is unlikely to occur in the laboratory. This may not be the situation under field conditions.

Aedes↗
PubMed1993

[Present status of zoonotic hemorrhagic fevers of South America].

Since 1958, the geographical distribution of Argentine hemorrhagic fever (AHF) has especially extended non only into the province of Buenos Aires but also towards the provinces of Santa Fe and Cordoba, leading to an estimated population at risk of about 1.2 M inhabitants. Recent epidemiological field studies has confirmed the major role of Calomys musculinus and C. laucha rodents in both transmission to man and conservation of Junin virus in nature. However, the human infection may result essentially from contacts with infected C. musculinus. Clinical condition of patients with AHF was greatly improved using AHF convalescent plasma and additional administration of vidarabin may still improve the results of treatment. A live attenuated vaccine, Candid No 1, is presently under evaluation in endemic foci of AHF. On the contrary Bolivian hemorrhagic fever (BHV) appears at present quite silent. A new disease resembling both AHF and BHF, the Venezuelan hemorrhagic fever, appeared in 1989 in the rural areas of central Llanos of Venezuela. The mortality was very high, reaching 23% or more among severely ill patients. The wild small rodents responsible for the disease were identified as Sigmodon alstoni and Zygotontomys brevicauda. Recent extension of agricultural practices and massive immigration may probably explain the recent emergence of this new viral zoonosis.

Animals↗
PubMed1993

Essaouira and Kala iris: two new orbiviruses of the Kemerovo serogroup, Chenuda complex, isolated from Ornithodoros (Alectorobius) maritimus ticks in Morocco.

Essaouira and Kala Iris viruses were isolated from Ornithodoros (Alectorobius) maritimus ticks parasitizing yellow-legged gulls (Larus cachinnans) on the coast of Morocco in 1979 and 1981, respectively. Serological evidence indicates that these two viruses are new members of the Chenuda complex within the Kemerovo serogroup of the genus Orbivirus. Ecological, pathological, morphological, and physicochemical properties are compatible with these findings. The infectivity of these viruses for man and animals, including seabirds, remains unknown.

Animals↗
PubMed1993

A rickettsia-like organism from Ixodes uriae ticks collected on the Kerguelen Islands (French Subantarctic Territories).

A rickettsia-like microorganism was isolated in suckling mice from Ixodes uriae ticks collected from penguins breeding on Mayes Island, Kerguelen Archipelago, French Subantarctic Territories. At isolation, this agent mimicked a tick-borne arbovirus. Finally, electron microscopy studies of infected suckling mouse livers showed the presence of inclusions filled with pleomorphic microorganism in the cytoplasm of some hepatocytes, sometimes dividing by binary fission and thus of obviously non-viral nature. No firm serological relationship was demonstrated with Chlamydia psittaci, C. trachomatis, C. pneumoniae, Coxiella burnetti, Cowdria ruminentium, Ehrlichia canis, E. phagocytophila, E. risticii or the WSU/1044 agent. The exact taxonomic position of the "Mayes" agent remains to be clarified.

Animals↗
PubMed1992

New developments in the molecular epidemiology of adenovirus 8 keratoconjunctivitis.

Four consecutive epidemics of keratoconjunctivitis caused by adenovirus 8 (Ad8) occurred over a 5-year period in Brest, France. A selection of 30 strains isolated during this period was studied by DNA restriction enzyme analysis using nine restriction enzymes. BglI and SacI were the most discriminative enzymes and allowed the recognition of four DNA variants, all different from the prototype strain Trim. Within each of the epidemics, the strains tested could not be distinguished in this analysis. Between strains from different epidemics differences in DNA structure could be detected however. Thus, the Ad8 epidemics of 1983/1984, 1984, 1987, and 1988 appear to have been due to DNA variants Ad8/D7, D8, D9, and D10, respectively. These results demonstrate that the DNA of Ad8 seems to display a considerable variability, comparable to that observed with Ad7 and Ad21. As has been described for Ad7, Ad21 and Ad41, successive DNA variants of Ad8 prevail during one or more years, and are then replaced by other, newly emerging variants sometimes associated with epidemics.

Adenovirus Infections, Human↗
PubMed1992

[Imported malaria in Brest hospitals from 1981 to 1990].

From 1981 to 1990, 96 confirmed hospital cases of imported malaria occurred in Brest. An important increasing of the annual number was observed in 1986. A high proportion of infection was due to Plasmodium falciparum, mainly from black Africa. Most of the patients was French young men, without or with inadequate chemoprophylaxis. Every case of malaria due to P. falciparum appeared during the 2 months following their return from an endemic area. Two patients had a clinical profile of visceral evolutive malaria and 5 a cerebral malaria. Three patients died.

Adult↗
PubMed1992

[Spiroplasma from Tabanidae capable to multiply and to persist in the central nervous system in mice].

Using alternate passages of cultivation in vitro at 37 degrees C and in suckling mice following intracerebral inoculation, a tabanid spiroplasma was demonstrated capable of multiplication and persistence in mice for 6 successive passages, without production of specific antibody. This is the first report of a spiroplasma from a common flying haematophagous arthropod shown to produce persistent infection of a mammal.

Animals↗
PubMed1991

Multiplication and persistence of Spiroplasma melliferum strain A56 in experimentally infected suckling mice.

Strain A56 of the bee pathogen Spiroplasma melliferum was isolated from a honeybee (Apis mellifera) during ecological studies on mosquito spiroplasmas in Savoie (France). When inoculated intracerebrally (i.c.) into 48-h old suckling mice, this strain was found to replicate to very high titres and to persist in brain for up to 9 months in one individual. We attempted to increase the "neurotropism" of A56 by sequential i.c. passages. During the first two passages, multiplication of the organisms was observed at very high titres in suckling mouse brain (10(7) to 10(11) CCU/ml) generally without the appearance of antibody, thus mimicking the so-called "immunological tolerance" phenomenon. Intracerebral multiplication of A56 decreased during the third passage (10(2) to 10(4) CCU/ml) and ceased during the fourth passage. Spiroplasma multiplication in brain was apparently well tolerated, since brain lesions were minimal and clinical symptoms were limited to a clear, but only rarely significant, delay in growth curves of inoculated versus non-inoculated mice. Progressive spongiform encephalopathy was never observed. Strain A56 S. melliferum appears as the second spiroplasma, after the tick-derived Spiroplasma mirum capable of multiplying in both invertebrate and vertebrate hosts.

Animals↗
PubMed1991

Spiroplasma (Mollicutes: Spiroplasmataceae) pathogenic for Aedes aegypti and Anopheles stephensi (Diptera: Culicidae).

Intrathoracic inoculation with the mosquito spiroplasma, Spiroplasma taïwanense Abalain-Colloc et al., was found to reduce significantly the survival of adult male and female Aedes aegypti (L.) and Anopheles stephensi Liston. This spiroplasma also reduced significantly the flight capacity of adult female Ae. aegypti 5-8 d after inoculation and adult female An. stephensi 4 d after inoculation. Adult female An. stephensi were incapable of flight 5 d after inoculation. As such, S. taïwanense joins Bacillus thuringiensis and B. sphaericus as bacteria known to be pathogenic for mosquito vectors.

Aedes↗
PubMed1991

Pathogenicity of Spiroplasma taiwanense for larval Aedes aegypti mosquitoes.

Helical replicative forms, but not the persistent non-replicative forms, of Spiroplasma taiwanense Abalain-Colloc et al. (isolated from the mosquito Anopheles sinensis Wiedemann in Taiwan) were shown to reduce significantly the survival of Aedes aegypti (L.) mosquito larvae reared in 10 ml of water with 0.3 ml of S.taiwanense suspensions added on days 0 and 3. The suspensions contained, respectively, helical forms at a concentration of 10(9) Colour Change Units (CCU)/ml and persistent forms at 10(6) CCU/ml. It is suggested that S.taiwanense, or toxins produced from it, are potentially useful for use in integrated mosquito control programmes.

Aedes↗
PubMed1991

Use of collagen shields in the treatment of herpetic keratitis.

Eighteen patients with typical Herpes simplex virus dendritic keratitis confirmed by viral isolation were treated with corneal collagen shields presoaked with trifluorothymidine for 15 minutes and trifluorothymidine eye drops 5 times daily. The average healing time was 2.9 days (range 1-7 days). No allergic reactions were observed. Toxic punctate keratitis occurred in 3 eyes. The results of this open study suggest that the effect of collagen corneal shields in conjunction with trifluorothymidine shortens the average epithelial healing time compared with other studies that have used antiviral drugs alone.

Adult↗