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Biomedical subjects

E Chungue

Publications and source records attributed to E Chungue.

At least 19 recordsLinked to original sources
PubMed1991

Dengue surveillance in French Polynesia: an attempt to use the excess number of laboratory requests for confirmation of dengue diagnosis as an indicator of dengue activity.

The excess number of weekly laboratory requests for confirmation of dengue diagnosis over the expected number of requests forecasted by the modified Serfling method is proposed for the surveillance of dengue in French Polynesia, in addition to conventional methods. Retrospective analysis of the seasonal curves of dengue activity related to the number of laboratory requests is described for the years 1982-1987 where dengue type 4 was the only active flavivirus at the time when the forecast was initiated. By using past epidemic data, the probability of failing to recognize an increase in excess of requests as possibly epidemic was of 13.2% and 5.8%, respectively, when the criterion for epidemic increase was set respectively at 2 and 3 successive weeks during which the epidemic threshold is exceeded. A weekly surveillance was set up prospectively for 1988 using these criteria.

Clinical Laboratory Techniques↗
PubMed1991

Oral infection of Aedes polynesiensis by Wuchereria bancrofti by using parafilm membrane feeding.

In order to construct a cDNA library from third-stage larvae (L3) of Wuchereria bancrofti var. pacifica, the Parafilm membrane feeding method is proposed for the oral infection of Aedes polynesiensis. Heparinized blood supplemented with 5.10(-3) M ATP was put in the feeder with carbon dioxide provided as additional phagostimulant. The results of this artificial infection feeding method were compared with those obtained when mosquitoes fed directly on the forearm of a microfilaremic patient. The number of females feeding through the artificial membrane was smaller than on the patient's forearm (32.1 vs. 84.8%). The mean number of L3s obtained per female was not statistically different between the 2 feeding methods; however, the total number of L3s obtained from 100 females allowed to feed in each group was twice as high in the natural feeding method.

Aedes↗
PubMed1991

[Materno-fetal dengue. Apropos of 5 cases observed during the epidemic in Tahiti (1989)].

During the dengue 3 epidemic which occurred in French Polynesia between September 1989 and March 1990, number of cases of Dengue Haemorrhagic Fever (DHF) were reported among children and infants. Of interest, five cases of neonatal infections were recorded and involved the transmission of the virus from mother to child as the end of the pregnancy. Detailed observations on these cases are presented in this paper. Fever in mother, when delivering or just a few days before, represents the circumstances of the diagnosis. Analysis of the clinical features shows that fever and vasomotor troubles (blotches) were the dominating traits of the disease in the newborns. Also, hepatomegaly was constantly observed. Concerning the biological results, thrombopenia (platelets count: 100,000/mm3) was reported for all cases. According to these data, all cases were classified into DHF cases. Laboratory confirmation was obtained by serological investigations (antidengue IgM immunocapture ELISA and Haemagglutination Inhibition Tests) and/or virus isolation in both mother and child. Thus, virus was recovered in two newborns while IgM were detected in all infants and in four mothers. Severity of the disease was variable. However, out of five cases one fulfills the WHO definition of Dengue Shock Syndrome (DSC). Moreover, the authors discuss about the difficulties encountered to classify the cases according to WHO criteria for the grade classification of DHF.

Dengue↗
PubMed1990

Identification of dengue sequences by genomic amplification: rapid diagnosis of dengue virus serotypes in peripheral blood.

Polymerase chain reaction (PCR) was developed for the in vitro amplification of dengue virus RNA via cDNA. A fraction of the N-terminus gene of the envelope protein in the four dengue serotypes was amplified using synthetic oligonucleotide primer pairs. Amplified products were cloned and used as dengue type-specific probes in gel electrophoresis and dot-blot hybridization. We detected and characterized dengue virus serotypes in blood samples by the three-step procedure DNA-PAH consisting in cDNA priming (P), DNA amplification (A) and hybridization (H) using specific non-radiolabelled probes. Our findings showed that DNA-PAH was more rapid and sensitive in the identification of the infecting serotype than the mosquito cell cultures. Moreover, the failure of cultures to detect virus particles in sera containing few copies of viral genome or anti-dengue antibodies justified the approach of DNA-PAH to the dengue identification in clinical specimens.

Base Sequence↗
PubMed1988

Chlamydia trachomatis genital infections in Tahiti.

The rate of Chlamydia trachomatis infection was determined in three populations in Tahiti by means of a direct immunofluorescence test performed in specimens, tissue culture and detection of chlamydial antibody in serum specimens using a single-serotype indirect immunofluorescence test. Chlamydia trachomatis was recovered in 53% of 53 bar girls, 24% of 75 women attending a public maternity clinic for routine care, and 37% of 71 men attending a sexually transmitted disease clinic with acute or subacute urethritis. The presence of chlamydial antibody in a high proportion of the groups studied confirmed the high frequency of chlamydial infections (62.3%, 66.6% and 83.1% respectively). Neisseria gonorrhoeae infection was often associated with chlamydial infection in both bar girls and men with urethritis (11.4% and 18.3% respectively). With regard to clinical manifestations, 58.3% (7/12) of bar girls and 23.2% (10/43) women at the maternity clinic without clinical complaints were found to be Chlamydia trachomatis-positive. The presence of Chlamydia trachomatis in these asymptomatic persons highlights their important role in spread of this organism in Tahiti. The findings indicate that routine testing for Chlamydia trachomatis is warranted in patients attending the sexually transmitted disease and public maternity clinics in Tahiti.

Adolescent↗
PubMed1979

[Enzyme immunoassay for the detection and identification of dengue viruses from infected mosquitoes (author's transl)].

The authors deal with a "double sandwich" enzyme immunoassay for the detection and identification of dengue viruses 1, 2 and 4. They use ground glass-beads (7 mm diameter) coated with human heterospecific anti-dengue antibodies, to bind viruses obtained from infected mosquitoes (Toxorhynchites amboinensis). The mouse antibodies bound to the viruses coated on the beads are revealed by anti-mouse 7S immunoglobulins labelled with peroxydase. The method is practical, sensitive and confident. The standard curves obtained with each type show significant differences from one another until very high dilutions of the viral suspension. Inhibition tests by human immune antibodies and dengue antigens demonstrate the specificity of the reaction. This method is certainly applicable to others arboviruses and allows a large scale epidemiological survey.

Animals↗
PubMed1977

[Toxic complex from parrotfish].

Clinical and epidemiological observations suggested that a complex toxic molecule is involved in the parrotfish flesh (Scarus gibbus) poisoning from Gambier Islands. The fat soluble extract obtained from the muscles upon ciguatoxin preparation showed two toxic substances after fractionation by DEAE cellulose column chromatography. The major toxin is different from ciguatoxin judging by its chromatographic behaviour. The other is closely similar to (or identical with) ciguatoxin from the moray eel Gymnothorax javanicus. They were named SG1 for the new toxin and SG2 for the ciguatoxin like compound. Successive filtrations on Sephadex LH-20 of SG1 and SG2 gave respectively a lethality to mice of 0.03 microgram/g and 0.06 microgram/g. SG1, specifically occurs in the muscles of the parrotfish family (scaritoxin) while it is absent from other ciguateric fishes. According to that specificity and the lack of SG1 in S. gibbus liver and gut contents, the origin of scaritoxin is briefly discussed.

Animals↗
PubMedDate not supplied

Comparison of immunoglobulin G enzyme-linked immunosorbent assay (IgG-ELISA) and haemagglutination inhibition (HI) test for the detection of dengue antibodies. Prevalence of dengue IgG-ELISA antibodies in Tahiti.

An immunoglobulin G enzyme-linked immunosorbent assay (IgG-ELISA) for the detection of dengue antibodies is described and compared to the haemagglutination inhibition test (HI). The sensitivity, specificity and agreement rate between the 2 techniques were good. The coefficients of correlation between IgG-ELISA and HI results, using dengue 1-4 antigens, were highly significant (P less than 0.001 for either antigen). IgG-ELISA was rapid, and easy to perform and suitable for large-scale studies. Between April and June 1987, a baseline serosurvey of the prevalence of dengue antibodies in age-stratified samples of children was carried out in Tahiti using IgG-ELISA. 327 children were tested against each dengue serotype. There was no significant difference between sex. Overall rates ranged from 7.4% in children under 5 years to 83.1% in those aged 15-19 years. Dengue 4 being the only serotype involved since 1979, specific responses to dengue 4 were found in higher proportion among children under 8 years old, while the IgG-ELISA responses were more widely reactive among children aged above 8 years (P less than 0.001). The acquisition rate of dengue 4 antibodies was 2.95% on average per year in children under 8 years of age.

Age Factors↗
PubMedDate not supplied

Dengue 1 epidemic in French Polynesia, 1988-1989: surveillance and clinical, epidemiological, virological and serological findings in 1752 documented clinical cases.

An epidemic of dengue 1 occurred in French Polynesia in December 1988 and June 1989. This paper records (i) the trend of the outbreak and its surveillance and (ii) the clinical, epidemiological and virological data obtained from 1752 documented cases. The epidemic reached its peak in February in Tahiti Island, 7 weeks after its recognition. Among 6034 suspect cases reported by sentinel physicians, 60.3% were < 20 years old. The illness was classical dengue. No fatality or case of dengue haemorrhagic fever/dengue with shock syndrome was reported. Of 4792 patients subjected to laboratory testing, 41% were confirmed as positive. The serological attack rate was c. 40%. The estimated number of dengue infections in the Windward Islands was about 20,000. Transmission was associated with Aedes aegypti. Study of documented cases showed a higher confirmation rate in both the civilian population < 15 years old (46.5%) and the susceptible French military population (47.6%) than in older civilians (31.1%, P < 0.05). Furthermore, primary dengue infections were predominant in both of the first 2 groups. The diagnosis was mostly confirmed (i) by virus isolation on day < 5 of illness and (ii) by detection of immunoglobulin (Ig) M on day > or = 5 of illness. The study showed that adequate surveillance of an epidemic requires both clinically and laboratory-based systems.

Dengue↗
PubMedDate not supplied

[Significance of IgM titration by an immunoenzyme technic for the serodiagnosis and epidemiological surveillance of dengue in French Polynesia].

The usefulness of IgM antibody capture enzyme-linked immunosorbent assay (ELISA-IgM) for the diagnosis of dengue was studied using several groups of sera. An attempt was made to detect IgM against each dengue serotype. Of 76 paired sera from patients with dengue type 4 infection, the diagnosis was confirmed by ELISA-IgM in 74: in 47 out of 49 primary dengue infections and in all 27 secondary dengue infections. It was possible to detect IgM in 15 of the acute sera of primary infections and in 16 of the acute sera of secondary infections. In 20 patients from whom only single serum with high haemagglutination-inhibition titre (greater than or equal to 640) was available, 18 were found positive for dengue IgM. Dengue infection was also confirmed in 10 patients with dengue type 1 and in 10 patients with dengue type 2. IgM was detected in 1 of the acute sera of patients with either dengue type 1 or dengue type 2 infection. In all cases in which IgM was detected, a positive response was obtained for the homologous antigen. ELISA-IgM on sequential serum samples from 7 proven cases of dengue type 4 revealed that antibody titres greater than or equal to 400 are reached early in the second week of the illness and persist for 60 days or more at a low level (titre less than 400). An attempt was made to obtain a type-specific presumptive diagnosis by analysing the relative titre against each of the 4 antigens. It was possible to make a diagnosis of dengue type 4 in 85% and 52% of IgM-positive responses in primary and secondary infections (p less than 0.01), respectively, using paired sera from patients with known dengue type 4 infection. ELISA-IgM was shown to be of interest in the diagnosis and surveillance of dengue in French Polynesia where dengue viruses are, presently, the only known flavivirus.

Antibodies, Viral↗