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At least 91 records · Page 5Linked to original sources
PubMed2005

Identification of hepatitis B virus genome in faecal sample from wild living chimpanzee (Pan troglodytes troglodytes) in Gabon.

Non-invasive faecal sampling in the equatorial forest in Gabon allowed the first identification of the hepatitis B virus (HBV-Ch(RC170)) genome in samples collected from wild chimpanzees (Pan troglodytes troglodytes). The HBV-Ch(RCl70)sequence clustered with 100% bootstrap support with previous viral sequences obtained from Pan troglodytes subspecies. This is the first evidence of HBV infection in wild apes and confirms that the HBV-like strains thus far characterized in captive apes are directly related to those circulating in the wild.

Animals↗
PubMed1998

Plasmodium falciparum: in vitro chloroquine susceptibility and allele-specific PCR detection of Pfmdr1 Asn86Tyr polymorphism in Lambarene, Gabon.

Plasmodium falciparum resistance to chloroquine has been described in many parts of the world particularly in Africa where malaria is endemic. High levels of chloroquine resistance in our study area, Lambarene-Gabon, has led to the use of an alternative regimen for treatment and prevention of P. falciparum infection. In this study, we examined the in vitro chloroquine sensitivity of 15 isolates from this area and assessed the prevalence of a putative chloroquine resistance associated Pfmdr1 polymorphism (Asn86Tyr) using a novel allele-specific polymerase chain reaction (PCR). Only 4 of the isolates examined were chloroquine sensitive. The allele-specific PCR shows that all 15 isolates carried the variant (86Tyr) codon. Eleven of these were resistant to chloroquine suggesting a 73% agreement between chloroquine resistance phenotype and the point mutation. This molecular marker was examined in a further 73 Gabonese isolates, where 58 (79.5%) showed 86Tyr and 15 (20.5%) showed 86Asn. In all, 4 (4.5%) of the 88 isolates assessed carry both mutant and wild-type codons, suggesting mixed parasite populations. The incomplete agreement found between chloroquine resistance phenotype and Pfmdr1 (86Tyr) polymorphism would support the view that other genetic factors as well as Pfmdr1 may be involved in chloroquine resistance. While our results suggest a high prevalence of 86Tyr polymorphism in Lambarene, the Asp1246Tyr polymorphism (a point mutation which to date has only been associated with South American P. falciparum) seems to be absent in our study area.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2004

Evidence of uranium and associated trace element mobilization and retention processes at Oklo (Gabon), a naturally radioactive site.

The processes that affect the mobility of uranium and other radionuclides in the environment have been largely studied at both the laboratory and the field scales. The natural reactors found at the Oklo uranium mine in Gabon constitute a unique investigation setting as spontaneous fission reactions occurred two billion years ago. Oklo uraninites contain a large amount of other radionuclides as a result of the fission process. We have investigated the dissolution behavior of four uraninite samples from Oklo as a function of temperature (25 and 60 degrees C) and bicarbonate concentration (2.7-30 mmol/L). We have also investigated the dissolution behavior of minor components of the uraninites (i.e., Nd, Cs, Mo, Yb, and Sb) in relation to the dissolution of uranium. The results of the reported work are in good agreement with the kinetic rate laws derived from other uranium(IV) dioxide studies. Some of the minor components are found to be congruently released from the uraninite phase, while it is postulated that dissolution from segregated phases might affect the final concentrations of some of the rare earth elements, i.e., Nd and Yb. In addition, we have performed dissolution studies at 60 degrees C with two uraninites representative of different geochemical environments at Oklo, to study the uranium dissolution rates as a function of the temperature. This has allowed derivation of apparent activation energies for the bicarbonate-promoted oxidative dissolution of the Oklo uraninites. The dissolution behavior of the minor components of the uraninites at 60 degrees C was found to closely follow the behavior observed at 25 degrees C. This indicates that similar codissolution mechanisms operate in the temperature range studied. The implications for the mobility of uranium and other radionuclides in natural and anthropogenic environments are discussed.

Environmental Monitoring↗
PubMed2001

High variability of HTLV-I in a remote population of Gabon as compared to that of a similar population of French Guiana.

An anomalous high frequency of ATL was observed in a remote 'noir maroons' village of French Guiana. Since it is not clear if HTLV-I is responsible for different frequencies of disease in different geographical areas, we undertook a comparison of the population with a similar one located in Gabon. We found a much higher degree of gp46 surface envelope glycoprotein sequence conservation in the Guianese village than in the Gabonese one.

Base Sequence↗
PubMed2006

Genetics of the Lp(a)/apo(a) system in an autochthonous Black African population from the Gabon.

Plasma lipoprotein(a) (Lp(a)) is a quantitative trait associated with atherothrombotic disease in European and Asian populations. Lp(a) concentrations vary widely within and between populations, with Africans exhibiting on average two- to threefold higher Lp(a) levels and a different distribution compared to Europeans. The apo(a) gene locus on chromosome 6q26-27 (LPA, MIM 152200) has been identified as the major quantitative trait locus (QTL) for Lp(a) concentrations in Europeans and populations of African descent (North American and South African Blacks) but data on autochthonous Black Africans are lacking.Here, we have analysed Lp(a) plasma concentrations, apo(a) isoforms in plasma and four polymorphisms in the LPA gene in 31 African families with 54 children from Gabon. Weighted midparent-offspring regression estimated a heritability h2=0.76. The correlation of Lp(a) levels associated with LPA alleles identical by descent (IBD) resulted in a heritability estimate of 0.801. Our data demonstrate that Lp(a) concentrations are highly heritable in a Central African population without admixture and high Lp(a) (median 43 mg/dl). LPA is the major QTL, explaining most or all of the heritability of Lp(a) in this population.

Adolescent↗
PubMed1998

IgG4 serology of loiasis in three villages in an endemic area of south-eastern Gabon.

Human filariasis due to Loa loa differs from other filariasis in that the majority of infected subjects are without circulating microfilariae (occult loiasis). In search for alternative diagnostic methods, which do not depend on circulating microfilariae or the (rather infrequent) eye-passage of adult worms, it was shown earlier that IgG4 antibodies directed against Loa loa adult worm antigen are apparently a good marker of occult loiasis and specific with regard to the sympatrically occurring Mansonella perstans. In this study we evaluated an IgG4 antibody-based ELISA using crude extract of Loa loa microfilariae (which is easier to obtain than adult worm) to estimate the prevalence of loiasis in 3 villages in South-East Gabon. Of 222 examined individuals (80 children < 16 years, 142 adults) 44 (20%) carried Loa loa microfilariae and 170 (77%) M. perstans. Using the mean OD-value + 1 standard deviation of 9 sera from patients solely infected with M. perstans (from the Gambia, where Loa loa is not endemic) as a cut-off, 35 of the 44 microfilaraemic Loa loa patients and 2 of the 9 Gambian controls were positive. This shows that our method had a sensitivity of 80% and a specificity of 78%. Among the remaining 178 subjects who had no microfilariae of Loa loa, as many as 97 (55%) had significant levels of specific IgG4 antibodies against Loa loa, suggesting that they carried occult loiasis. The mean IgG4 level in these putatively occult loiasis patients was slightly but significantly lower than in microfilaraemic subjects (P < 0.03). In conclusion, despite the limited sensitivity and specificity of our method, IgG4- ELISA at present is a very useful tool in estimating the real prevalence of loiasis in epidemiological surveys and at the individual level can confirm the diagnosis of L. loa amicrofilaraemic subjects with clinical signs suggesting loiasis.

Adolescent↗
PubMedDate not supplied

[Hepatocystis brosseti n. sp. Haemproteidae, parasite of Epomops franqueti, Pteropinae, in Gabon].

Epomops franqueti (Pteriopinae) trapped around Makokou (Gabon) are frequently infected with Hepatocystis brosseti n. sp. Blood smears and tissue sections were made; all schizonts were found in the liver except a single one in the spleen. In liver, near maturity the schizonts are extracellular, convoluted, medium sized (250 mu) and filled with abundant colloidal substance.

Animals↗
PubMed1984

Anatomical adaptation to haplodiploidy in the Oxyuroid (Nematoda) Desmicola skrjabini n. sp. from a diplopod in Gabon.

Desmicola skrjabini n. sp. (Oxyuroidea; Nematoda) is described on the basis of female morphology from the hind-gut of Pachybolus sp. ( Pachybolidae ; Spirobolida ; Diplopoda ) from Gabon. The new species differs from the type and only other species in lacking interlabial formations and obvious cephalic papillae, and in having what appear in apical view as finger-like cuticular ornamentations on the anterior surface of the lips. D. skrjabini is didelphic and a seminal receptacle is present in only one branch of the reproductive tract. In oxyuroids , males develop from unfertilized eggs whereas females develop from fertilized eggs. It is suggested that the curious reproductive anatomy of Desmicola ensures production of eggs of both types and therefore offspring of both sexes.

Adaptation, Biological↗
PubMed1988

[New atractid nematode parasites of the chimpanzee and gorilla in Gabon].

Females of the genus Probstmayria, collected in feces of wild Chimpanzees and Gorillas, living in the Lope-Okanda reserve in Gabon, are described. The cephalic structures of P. gombensis File, 1976 from Chimpanzee and P. gabonensis n. sp. from Gorilla are similar to those of the other species of the genus. In contrast, the cephalic structures of P. inversa n. sp. from Chimpanzee and P. goodallae n. sp. from Gorilla are unusual; they have an inverse symmetry (one ventral lip and two latero-dorsal lips). The original characteristics of the genus Probstmayria are analysed.

Animals↗
PubMed1995

Filariae from a wild gorilla in Gabon with description of a new species of Mansonella.

A search for filariae was performed on a wild male Gorilla g. gorilla from the Lopé Reserve in Gabon, which had died as a result of injuries inflicted by another male gorilla. A female worm of Loa loa and female worms of two species of Mansonella were recovered from the deep tissues of a wounded thigh. In order to analyze these Mansonella, specimens of M. (E.) perstans, M. (E.) vanhoofi and M. (E.) streptocerca from the Collections of the Museum National d'Histoire Naturelle de Paris have been studied and new important discriminative characters characterised, such as the body-swellings in M. (E.) perstans, due to the presence of coelomocytes as in South-american M. (Tetrapetalonema) spp. One of the Mansonella from this gorilla was not identified, but the body-swellings and the microfilarial morphology suggested a possible similarity with M. (Esslingeria) perstans. The other species is new; M. (E.) lopeensis n. sp. is distinguished by its large size, lack of body-swellings, structure of the tegumental sheath, complex vagina, and a tail with a subterminal constriction, a terminal bend and large lappets. Histological sections of organs of this gorilla also showed a microfilaria of M. (E) leopoldi in the blood vessels of the liver, and a male of Mansonella sp., interestingly situated in an afferent lymphatic vessel of an axillary lymph node.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Intestinal parasites of sympatric gorillas and chimpanzees in the Lopé Reserve, Gabon.

A coprological survey of intestinal parasites of wild chimpanzees (Pan t. troglodytes) and western lowland gorillas (Gorilla g. gorilla) was carried out in the Lopé Reserve in central Gabon. Most samples (69%) were positive but the prevalence of intestinal parasites in the 61 gorilla samples (84%) was higher than in the 66 chimpanzee samples (56%). At least 11 species of parasite were observed: six protozoan, one trematode and at least four nematodes. Six of the species were found in gorillas and chimpanzees but the remainder only occurred in chimpanzees. All but one parasite occurred at low prevalences. Entodiniomorph ciliates, which occurred frequently in both ape species (particularly in gorillas) in the Lopé survey and in all previous coprological surveys of wild apes, may be symbionts involved in cellulose digestion. The dietary and behavioural strategies of wild primates that serve to reduce infection by pathogenic parasites are reviewed.

Animals↗
PubMed1990

Hendersonula toruloidea as an agent of mycotic foot infection in Gabon.

Pathogenic fungi were isolated from 149 of 210 Gabonese patients with clinical signs of tinea pedis. Hendersonula toruloidea was isolated from 51 patients (34.2%), either alone (in 25%) or in association with a dermatophyte species or Candida albicans. Clinical signs of H. toruloidea infection closely resembled those of dermatophyte infection except that hyperkeratinization of the soles was most often associated with infection by H. toruloidea. H. toruloidea mycelium could be readily distinguished from dermatophyte mycelium on direct examination of skin scrapings. All the H. toruloidea isolates closely resembled the Type 1 isolates described by Moore, both microscopically and macroscopically. The importance of establishing a mycological diagnosis of this infection and the therapeutic implications of infection with H. toruloidea are discussed. This fungus was isolated from 34% of our patients from Gabon with clinical tinea pedis.

Adolescent↗
PubMed2005

Amplification of Plasmodium falciparum multidrug resistance gene 1 in isolates from Gabon.

The study of molecular markers of drug resistance is particularly important in surveillance studies of drugs, such as mefloquine, that still retain efficacy in sub-Saharan Africa yet have encountered resistance elsewhere. In a recent study in Thailand, we identified amplification of the Plasmodium falciparum multidrug resistance gene 1 (pfmdr1) as being the most important predictor of in vitro drug resistance and in vivo failure of mefloquine monotherapy. Here we report amplification of pfmdr1 in >5% of patient samples from Lambarene, Gabon, collected in 1995. None of the samples collected 7 years later showed pfmdr1 amplification, suggesting that parasites with increased numbers of pfmdr1 copies have not substantially spread through the population. Nevertheless, the detection of multicopy pfmdr1 in African parasites suggests a high potential for rapid selection for resistance, implying that mefloquine use in Africa should be considered only as part of combination therapy.

ATP-Binding Cassette Transporters↗
PubMed1999

Ebola hemorrhagic fever outbreaks in Gabon, 1994-1997: epidemiologic and health control issues.

From the end of 1994 to the beginning of 1995, 49 patients with hemorrhagic symptoms were hospitalized in the Makokou General Hospital in northeastern Gabon. Yellow fever (YF) virus was first diagnosed in serum by use of polymerase chain reaction followed by blotting, and a vaccination campaign was immediately instituted. The epidemic, known as the fall 1994 epidemic, ended 6 weeks later. However, some aspects of this epidemic were atypical of YF infection, so a retrospective check for other etiologic agents was undertaken. Ebola (EBO) virus was found to be present concomitantly with YF virus in the epidemic. Two other epidemics (spring and fall 1996) occurred in the same province. GP and L genes of EBO virus isolates from all three epidemics were partially sequenced, which showed a difference of <0.1% in the base pairs. Sequencing also showed that all isolates were very similar to subtype Zaire EBO virus isolates from the Democratic Republic of the Congo.

Antibodies, Viral↗
PubMed1994

Clindamycin in combination with chloroquine or quinine is an effective therapy for uncomplicated Plasmodium falciparum malaria in children from Gabon.

Multidrug resistance of Plasmodium falciparum is becoming common in Africa. In a randomized trial, four short-term regimens were compared for treating uncomplicated P. falciparum malaria in children 4-15 years old in Gabon. One hundred thirty patients received chloroquine (25 mg/kg over 48 h; group C), chloroquine (as above) plus clindamycin (5 mg/kg every 12 h for 6 doses; group CCl), quinine (12 mg/kg every 12 h for 6 doses; group Q), or quinine (as above) plus clindamycin (as above; group QCl). In group C, only 9% of patients were cured by day 28, 44% showed recrudescent malaria (RI), and 47% showed intermediate or high-grade resistance (RII/RIII). In group CCl, 70% of patients were cured and 30% showed recrudescences. In group Q, 32% were cured and 68% showed recrudescences. In group QCl, 88% were cured and 12% showed recrudescences after day 14. All treatment regimens were well tolerated. Thus, the combination of clindamycin with chloroquine or quinine enhances parasite clearance and improves response to therapy.

Adolescent↗
PubMed1992

Efficacy, safety and acceptability of halofantrine in the treatment of acute Plasmodium falciparum malaria in African children (Gabon).

Halofantrine chlorhydrate 2 per cent suspension was given to 50 children (mean age 6.2 years in a dose of 8 mg/kg three times a day as a single day treatment. The children were born and lived in Gabon, where malaria transmission is continuous. They all had acute Plasmodium falciparum malaria. The children were kept in hospital for 5 days, and regularly followed over a 15-day period. The 50 children were cured and efficacy was evaluated as good in 44 cases, and excellent in six cases, as judged by improvement in their clinical signs and parasitaemia. Two criterias were considered in the evaluation of efficacy: clearance of parasitaemia (mean day 4), fever clearance (mean hour 24). There were two cases of persistences of parasites at day 15 with a very low parasitaemia rate. Tolerance to halofantrine was good from a clinical and biological point of view. Acceptability was excellent in all cases. Halofantrine 2 per cent suspension is a good alternative in the treatment of acute Plasmodium falciparum malaria in children, especially with the present situation of multidrug-resistant strains in Central Africa.

Acute Disease↗