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Biomedical subjects

P Coulanges

Publications and source records attributed to P Coulanges.

At least 19 recordsLinked to original sources
PubMed1992

Malaria transmission and vector biology on Sainte Marie Island, Madagascar.

A 17-mo longitudinal malaria survey (November 1988-March 1990) was carried out on Sainte Marie Island, an area on the east coast of Madagascar which is frequently visited by tourists. During 706 man-nights of capture, 46,401 mosquitoes belonging to 32 species were caught. Sporozoite rates were determined by ELISA and incriminated Anopheles gambiae Giles s.s., An. funestus Giles, and An. mascarensis De Meillon as vectors of malaria. An. gambiae, the main vector, was highly anthropophilic but largely exophilic. Transmission by this species occurred mainly from November to April; the overall circumsporozoite antigen positivity rate was 1.7%, with a maximum of 3.2% in March-April. The nightly peak of transmission occurred between midnight and 0400 hours. The annual inoculation rate was calculated to be 100 infective bites per human, of which 92 were of Plasmodium falciparum. An. funestus played a minor role in transmission. An. mascarensis, an anopheline endemic to Madagascar, was incriminated for the first time, as a malaria vector. The sporozoite rate in this species varied from 0.4 to 0.9% as shown by both ELISA and salivary gland dissections. Parasite indices in humans up to 20 yr of age fluctuated during the year from 64 to 80%. Bed nets are recommended for malaria protection for the local population and tourists.

Animals↗
PubMed1991

Transmission and epidemiology of newly transmitted falciparum malaria in the central highland plateaux of Madagascar.

The recent reappearance of Plasmodium falciparum in the central highland plateaux of Madagascar has led to an important increase in both morbidity and mortality in the population. To understand the phenomena that originated this outbreak, and to evaluate the clinical and biological reactions of the population, we conducted entomological surveys during the whole malaria transmission season of 1988. In parallel, 41 individuals presenting with a malaria attack in January were given a curative antimalarial treatment and were followed weekly for 20 weeks, until the end of the transmission season, in June. During the follow-up, individuals presenting with a clinical malaria attack or with a parasite density above 5000 per mm3 of blood were again given antimalarial treatment. Overall, individuals presented with an average of 5.6 thick blood smears positive for P. falciparum, and 1.4 malaria attacks requiring treatment. Plasmodium falciparum prevalence rates gradually increased to 53.8% in April, one to two months after the observed peak of transmission, then decreased to 15.4% at the end of follow-up. The proportion of P. falciparum infections with clinical symptoms did not follow a similar temporal evolution and was significantly lower than at enrollment. Splenic rates gradually decreased from 29.3-2.6%, while anti-P. falciparum and anti-Pfl55/RESA antibodies increased. For the whole transmission season individuals experienced a mean 1.5 infective bites; the malaria vectors were Anopheles gambiae s. 1 and An. funestus. This study demonstrates that, in this population newly exposed to P. falciparum infections, almost all sporozoite inoculations lead to blood parasite infection requiring treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Protective value of elevated levels of gamma interferon in serum against exoerythrocytic stages of Plasmodium falciparum.

In vitro experiments suggested that gamma interferon, CD8+ T cells, and anticircumsporozoite antibodies inhibited the exoerythrocytic stages of malaria parasites. To assess the role played in vivo by these factors, we conducted a prospective study in Madagascar. Forty individuals with a negative blood smear were followed for 8 weeks to detect the appearance of parasites in blood. Nineteen subjects remained negative for malaria, whereas 21 individuals became positive during follow-up. Among these, seven presented with blood parasites within the first 2 weeks and were excluded, as they probably were infected by sporozoites at enrollment. When measured at enrollment, antibodies to the synthetic peptide (NANP)5, lymphocyte proliferation with (NANP)5, and various lymphocytes subsets were similar among individuals that later presented with a Plasmodium falciparum blood infection or were not infected. Conversely, the level of gamma interferon in serum was higher in individuals that did not present with a P. falciparum infection during follow-up. These data suggest that gamma interferon may inhibit the malaria exoerythrocytic stages of development under in vivo conditions, as it does in vitro.

Adolescent↗
PubMed1991

[Longitudinal study on malaria transmission and biology of vectors in the island of Sainte Marie, on the east coast of Madagascar, from 1988 to 1990].

A 17-month longitudinal malaria survey was carried out in Sainte Marie Island, on the East Coast of Madagascar, from November 1988 to March 1990. During 706 man-nights of captures, 46401 mosquitoes belonging to 32 species were caught. Sporozoïte rates were calculated by Elisa. The malaria vectors were Anopheles gambiae sensu stricto, An. funestus and An. mascarensis. An. gambiae was the main vector. It was highly anthropophilic and partially exophilic. Transmission by this species mainly occurred from November to April, monthly sporozoïte antigene positivity rate varied from 0 to 3.85. The annual inoculation rate was about 100 infecting bites per man, in which 92 by Plasmodium falciparum. An. funestus intervened weakly in transmission. An. mascarensis, a malagasy endemic region anopheline is a newly discovered vector. The observed sporozoïte rate varied from 0.4 to 0.9 between September and March 1990. Parasite indexes in human fluctuated during the year from 64 to 80%. Because of the high level of transmission, recommendations for inhabitants and tourists are proposed.

Adolescent↗
PubMed1991

[Prevalence of antibodies to West Nile virus in youngsters from 5 to 20 years old in Madagascar].

In 1990 a serological investigation among 3,177 children (5 to 20 years old) sera has been conducted by the Pasteur Institute of Madagascar in several areas of Madagascar, in order to evaluate the prevalence of West Nile virus antibodies. 29.9% out of human sera tested by ELISA for West Nile IgG antibodies are positive, that shows a rather high level of West Nile virus circulation in Madagascar. Prevalence is increasing with age but no significant difference has been registered among prevalence according to sex. The diffusion of the virus appears lighter in Central Highlands.

Adolescent↗
PubMed1990

Longitudinal study of the cellular response to Pf155/RESA and circumsporozoite protein in Madagascar.

In a community follow-up conducted in the Central Highlands of Madagascar, the cellular responses to synthetic peptides from the immunodominant regions of Pf155/RESA and the repeat region of the circumsporozoite protein were studied. Seasonal variations of the T cell response were measured at the individual level; the relationship between this response and the presence of parasites in blood was assessed; the question of the possible protective value of the lymphocyte proliferation in presence of a specific antigen was addressed.

Adolescent↗
PubMed1990

Malaria transmission and vector biology in Manarintsoa, high plateaux of Madagascar.

To evaluate the factors which determine the transmission level of falciparum malaria, entomological and parasitological surveys were conducted from October 1988 to February 1990 in Manarintsoa in the central highland plateaux of Madagascar. Mosquitoes were collected for 928 man-nights in pit shelters and indoor resting sites. Malaria vectors were Anopheles arabiensis and An. funestus, with no evidence of the presence of An. gambiae sensu stricto. Vectors were mainly exophilic and zoophilic. The index of stability was less than 1.5. The sporozoite rate was 0.11 for An. gambiae sensu lato and 0.47 for An. funestus. The transmission level was low, with an inoculation rate of 0.91 infective bites/person/year and an infection risk of 0.62. Malaria transmission occurs 7 months of the year in this area, from November to May. Human parasite rates fluctuated from 29% in October to 53% in May.

Animals↗
PubMed1990

Humoral and cell-mediated immune responses to the Plasmodium falciparum antigens PF155/RESA and CS protein: seasonal variations in a population recently reexposed to endemic malaria.

Resurgence of falciparum malaria occurred in the Central Highlands of Madagascar in the 1980s and the disease is currently hyperendemic. We determined the humoral and cellular responses to synthetic peptides reproducing the repeat sequences of 2 major Plasmodium falciparum antigens: the Pf155/RESA and the circumsporozoite (CS) protein. Blood samples from 83 subjects living in a rural community near Antananarivo were obtained at the beginning and the end of the transmission season. At enrollment, 40 subjects presenting with and 43 without blood parasites had similar T cell proliferative response and antibody level to all antigens tested. However, P. falciparum-infected individuals exhibited a decrease in the absolute number of T lymphocytes, due to a diminished number of CD8+ and natural killer lymphocytes. The number of CD4+ cells was similar in both groups. In the overall population, 45% of subjects had a T cell response to at least 1 RESA peptide (29-35% responding to a given peptide) and 35% to the CS protein peptide. Thirty-two percent of the donors presented with RESA antibodies and 23% had CS protein antibodies. After 20 weeks, at the end of the transmission season, cellular proliferative responses to all antigens markedly decreased as evidenced by a decrease of both the number of responders and mean stimulation indexes. Humoral response to RESA, as detected by erythrocyte membrane immunofluorescence (number of responders and mean antibody titers) markedly increased. Humoral responses to the CS protein and RESA peptides were similar.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[The Wesselsbron virus, a new arbovirus for Madagascar].

Wesselsbron virus, an African arbovirus group flavivirus, has been isolated in 1989 for the first time in MADAGASCAR from Aedes circumluteolus collected inside primary forest near the village of MAROVITSIKA. Serological studies in man using haemagglutination inhibition test have permitted to think that Wesselsbron virus have circulated quietly in MADAGASCAR. The detection of Wesselsbron antibodies in Lemurs sets the problem of the biological cycle.

Aedes↗
PubMed1990

[Serodiagnosis of cysticercosis by ELISA and western blot. Their value and limitations in Madagascar].

Cysticercosis is linked to the infestation of men (or pigs) by the larval stage of Toenia solium: Cysticercus cellulosae. This disease, very common in the Third World, represents in Madagascar, a very serious problem for Public Health. Neurocysticercosis, particularly, must be detected before the stage of evolution towards cicatrisation. Two biological tests have been developed: 1) ELISA test: Cysticercus antigen is prepared from pig cysticercus, with addition of PMSF: proteases inhibitor increasing antigen stability. We present sensitivity and specificity studies of the test. 2) Western Blot test: E.I.T.B.: this test completes first test in case of negative ELISA test with clinical signs. In this case, evolving diagnosis is supported by low weight proteins revelation by patient's serum. These two tests applied to 100 positives cases have permitted the chemotherapy indication, with favorable results in more that 80% of the cases.

Blotting, Western↗
PubMed1990

[Use of monoclonal antibodies for the antigenic analysis of West Nile viral strains isolated in Madagascar. Contribution to the understanding of the epidemiological cycle].

The antigenic relationship of 53 MADAGASCAR West Nile isolates to each other and to the two prototype viruses (Eg 101 and G 2266) was assessed using monoclonal antibodies. In MADAGASCAR exist 5 antigenic groups: 4 which are much closer to the Egyptian strain Eg 101 than to the Indian, and antigenically distinct from South african H 442 strain. One other is closely related to Indian strain G 2266. Antigenic variations are observed in every periods of transmission cycle. Some differences between strains isolated in a same region are also observed. MADAGASCAR is an exchange place for West Nile virus through the instrumentality of migratory birds.

Aedes↗
PubMed1990

[Rapid diagnosis of rabies by the ELISA method. Its application in Madagascar: advantages and disadvantages].

ELISA technique in the rabies rapid diagnosis is compared with other methods used in the PASTEUR Institute of MADAGASCAR (immunofluorescence, mouse inoculation, and histopathology). The results of the comparative study of 80 samples of suspect animals show that ELISA sensibility is better than immunofluorescence one. Sensibility, specificity and viability of ELISA are comparable with those of the two confirmation techniques. In MADAGASCAR, ELISA is adapted to testing samples not conserved in good conditions, exposed to heat, after a big travelling time. It is to be hoped that samples are numerous to control rabies: in this condition price of ELISA is not expensive.

Animals↗
PubMed1990

[Surveillance of influenza in Tananarive. 1989].

The authors report results of epidemiological survey of influenza in TANANARIVE. This survey is based on respiratory morbidity observed in an interprofessional health center, and virus isolation. Two viruses have circulated in 1989: B virus (B/VICTORIA/2/87) during first half-year, and A: A/VICTORIA/36/88 (H1N1) virus during dry season with a pick in November. Influenzae has been responsible of grouped sporadic cases without epidemic diffusion.

Adolescent↗
PubMed1990

[Infantile diarrheal diseases in Madagascar: bacterial, parasitologic and viral study].

From November 1988 to October 1989, an etiological study showed off the prevalence and the part of several enteropathogen agents which are not yet studied in MADAGASCAR. 1,523 stool's samples from 884 children with diarrhea and 639 children without diarrhea from 0 to 14 years old have been investigated. A bacterial, parasitical or viral etiology was found from 36.3% of diarrheic children and 11.2% of healthy children. The three agents the most frequently identified from children with diarrhea are EPEC (10.5%), Campylobacter jejuni (10.3%) and rotavirus (10%) and associations of two or three pathogen agents are frequent (6.2%).

Adolescent↗