Biomedical subjects
Publications and source records attributed to D Richard-Lenoble.
In examining skin snips from 1,830 Gabonese 32 were found to have microfilariae indistinguishable from Microfilaria rodhaini. The microfilaria is 300.2 microns long and 2.2 microns wide. Specific clinical signs were not identified, as the same person often was infected by other filaria.
In permanent malaria transmission area (Gabon), fluorescent malarial antibodies have been studied among a population of mothers new borns and children from 1 to 15 years old. A lack of transplacental transfer of antibodies among african pairs "cord-mother" is noticed and in negative correlation with total mother IgG level. The antibodies rapidly increase from 1-2 years old still 9. Chimioprophylaxis does'nt modified for a long time the development of the FAT malarial antibodies.
The transplacental transfer of toxoplasmosis antibodies has been compared between european and african cord/mother ratios. A lack of transfer is statistically noticed among african cord-mother pairs. This transfer deficiency is highly significantly negative correlated with mother total IgG level.
The 2-nitro-imidazole derivative Ro 15-0216, closely related to benznidazole used for the treatment of South American trypanosomiasis (T. cruzi) proved effective against T. brucei brucei and T. brucei rhodesiense in rodents and sheep models. Diffusion in CSF is large in dogs and sheep. We studied splenectomised or immunodepressed mice and rats, infested with T. brucei gambiense human strain T-M1 isolated from a Gabonese patient with sleeping sickness. 2 groups of 5 mice were treated with oral doses of 50 mg/kg and 100 mg/kg for 3 days. 3 mice were injected with 10 mg/kg intraperitoneally. 3 rats were given 50 mg/kg orally for 2 days. 3 rats were injected with 25 mg/kg, 4 rats with 10 mg/kg, 2 rats with 100 mg/kg intraperitoneally. 13 animals were "controls". A dose of 10 mg/kg was rapidly active against the parasites circulating in blood. The diffusion in CSF was not studied. No side effects have been observed. 24/25 treated rodents were in good health without parasites in the blood at Day 12.
The transmission of malaria occurs mainly in and following the rainy season (intermittent transmission) in the Sahelian zone of Africa. On the other hand in rainy Equatorial Africa the transmission of malaria is continuous so that it is stable and can give rise to continuous antigenic stimulation in pregnant women which in turn gives rise to passive early high level immunity in the infant. 150 couples of mother and cord blood and 206 placentae were studied. We found 12.1% of carriers of blood parasites in the blood as compared with 1.6% in the cord bloods (exclusively P. falciparum). Where there were medium quantities of fluorescent antibodies in the mothers 74% could be found in the cord serum. Two methods were used to measure antimalarial antibodies as evidence of infection and also partly protective: the first method was indirect immunofluorescence, and the second was co-electrosyneresis. There was a narrow correlation between the level of precipitant antibodies in the mothers who were infected and in the fetal cord bloods. Anatomo-pathological examination of the placenta showed that 2 out of the 206 had parasites in them, 9 out of the 206 had fibrin deposits around the villi and 6.8% of the placentae showed lesions of malaria. On the other hand, in West Africa there was very little maternal morbidity as evidence by fever and anaemia, or of fetal morbidity. There was no single case of congenital malaria. The levels of the plasma indices in the towns could be explained because of prophylaxis which was both controlled and uncontrolled.
Explore the source record for details and available documents.
The distribution of carriers of hematozoa in the pre-school and school age group in Gabon has been established with the help of systematic enquiry. The plasmodial indexes vary between 11 and 32% in the savanna zones of the south-east, they rise to 64.9% in the forest regions of the north of the country, and in the urban zones (Libreville, Franceville, Lambarene) 6 to 18% of the school children are gametocyte carriers. In Libreville, amongst the febrile children seen in pediatric consultation, the prevalence reached 30%. Boys and girls are equally affected. The most important prevalence is observed in the group of children from 5 to 10 years of age. P. falciparum is found in 96.4% of the cases, P. malariae in 5.3% and P. ovale in 2.4%. The study of the parasitic load revealed that 56% of the positive subjects had less than 10,000 asexual forms/mm3, 44% more than 10,000 hematozoa/mm3. These results are similar to those of the neighbouring countries of equatorial Africa.
Close interactions between salmonellae and Schistosoma intercalatum were demonstrated by a study of 118 children conducted at Libreville, Gabon. Bilharziasis, confirmed by rectal biopsy, was present in 76% of children hospitalized for typhoid-like salmonella septicaemia, as against 38% of controls of the same age living in the same district (P less than 0.001). Although the clinical symptoms were typical of typhoid fever, with stupor, myocarditis or leucopenia depending on the cases, the germs responsible in 26 out of 42 cases were salmonella species regarded as minor. Finally, the salmonella infection was clinically prolonged by bilharziasis in 1 out of 3 patients. It would therefore appear that salmonella adheres to the wall of S. intercalatum as to that of other schistosoma species, and that both infections must be treated concomitantly.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Intestinal parasitic infection was determined by fecal examination for parasites with several complementary methods in 380 young Gabonese infants aged 6 to 24 months (190 with normal weights and 190 with malnutrition, matched for age). Trichuris trichiura, Ascaris lombricoides, Giardia intestinalis, Entamoeba histolytica and Strongyloides stercoralis were the most prevalent parasites, without any difference between well-fed infants and patients with malnutrition. The higher prevalence of Strongyloides stercoralis in protein energy malnutrition might be related to a methodologic problem. However, more than 20% of diarrheas in infants with severe malnutrition were dramatically improved by specific treatment of S. stercoralis or Giardia with thiabendazole or metronidazole.
Among 500 febrile children who came for medical examination in the Pediatric Department at the Hôpital Général de Libreville, 29.2% were infected by malaria. P. falciparum was the most common (96.7%), P. malariae and P. ovale were sparsely present. Rarely detected in people consulting for fever, shivering and headache were the two symptoms directly related to paludism. There is a direct correlation between the size of the spleen and the rate of infestation. Screening among babies from 3 to 6 months' old, shows 13% already infected. The top of malaria incidence lies between 2 and 3 years of age (42% were infected).
The identification of different infectious agents found in infantile diarrheas was undertaken in 237 children hospitalized in pediatric institutions in Libreville. In neonates between 0 and 18 months of age, the most common pathogen was Rotavirus (20.6%), followed by Shigella (10.8%), E. coli (9.24%), Salmonella (3.46%), E. histolytica (0.8%) and Y. enterocolitica (0.4%). The highest percentage of diarrheas caused by rotaviruses was found among children between 6 and 11 months of age. The frequency of Salmonella among children 2 to 4 years of age is almost the same at that in children under 2 years of age (3.44%). Isolation of Shigella in this group reaches 12.06%. The protective effect of breast milk and the carriage state among adults are discussed.
Explore the source record for details and available documents.
Rotaviruses are the main etiology of acute diarrhoeas in gabonese children (11 to 30% according to age). Salmonellae (11.4%), Shigellae (7.1%) and E. histolytica (7.1%), isolated or associated with enterobacteria, E. coli (3%), Giardia and Strongyloides stercoralis (1.4%), Yersinia enterocolitica (1%) and Balantidium coli (0.5%) were also found, without cholera.
Parasitic infections are endemic in children in Africa, making eradication an impossibility. Therapy is directed towards the individual manifesting an imbalance in the host-parasite relationship. Sanitation education is often disappointing, and until effective vaccines are developed, drug therapy remains the only worthwhile intervention. In order for a drug to be used on a mass campaign basis, financial considerations and side effects are of primary importance. Mefloquine has been shown to be a useful second line drug for chloroquine resistant strains of malaria in our Parasitology department. Benzimidazoles in a single dose are useful for intestinal nematode infections. New drugs are now available for schistosomiasis, filariasis, and protozoan infections.
In endemic regions, certain anti-parasitic therapies are automatically prescribed when confronted with apparently benign childhood disorders. The diagnostic differentiation between a simple febrile seizure provoked by Plasmodium falciparum is often impossible, requiring the initial use of intravenous quinine. Helminth or Giardia infestations often aggravate the chronic diarrhea of malnutrition, or are revealed with corticosteroid therapy, necessitating the initiation of an appropriate treatment. In addition, the frequent association of typhoid and schistosomiasis, requires therapy for both in order to prevent relapses.
Mebendazole (Vermox 500) in long duration treatment 2 g/day for 3 to 4 weeks, is sometimes indicated in therapy of Loa Loa filariasis but remains the only active therapy on M. perstans filariasis. The perfect product tolerance and efficacy allow large indication in treatment of this last filariasis, the most often found in Gabon (Central Africa).