Biomedical subjects
Publications and source records attributed to M Merlin.
The authors report the results of 3 sample surveys carried out in Libreville, Ngounié and Haut-Ogooué Provinces to evaluate the main malarial indexes among 0 to 15 years old children in Gabon. These investigations would suggest that malaria is mesoendemic in the three areas. The systematic presumptive antimarial treatment of fever attacks is widely used in Libreville but not so frequent in rural areas.
The focus of African human trypanosomiasis at Douala was evaluated in 1973 for the last time. The authors report on the results of their prospective survey. The methodology was characterized by utilizing Testryp C.A.T.T. as immunological case finding field test. 11,614 people were surveyed and 5 positive CATT revealed. But such results have be weighted by the rate of people present (52.2%) and by the fact that the selected area was not fully covered. On the other side, the authors examine the operational feasibility of Testryp CATT as immunological case finding field test. Over almost 12,000 tests performed, the feasibility appears very good.
The method of Tukey shows a graphic view of a distribution of data around its median. This graphic representation is simple, easy, pertinent and computer-compatible. It optimizes the description of distribution of data (normal or free distribution). Usable with small size samples, the Tukey test is not very powerful, but robust, and authorizes a comparison of two or more medians with a risk of 5%.
The authors report the results of sample surveys carried out in september 1986 in Yaounde and Nanga-Eboko and in january 1987 in Edea (Cameroon) to evaluate the main malarial indexes among 0-15 years old children. These investigations suggest that malaria is hypoendemic in Yaounde and mesoendemic in Nanga-Eboko during the rainy months. In Edea malaria is hyperendemic.
The efficiency of the African Year of Immunization has been studied in Cameroon by the evaluation of the nationwide coverage thanks to two cluster sample surveys carried out in rural and urban areas. The results are compared to those of previous surveys.
Since 1985, OCEAC, the organization for control of widespread endemic disease in Central Africa, has managed an epidemiological surveillance programme concerning HIV infection and AIDS in six countries of the Sub-Region: Cameroon, Tchad, Central African Republic, Congo, Equatorial Guinea and Gabon. This programme consists in evaluating longitudinally incidence rates of infection and clinical cases, and mortality rates. It is based on a selective strategy using a network of sentinels (hospitals and maternity care consultation centers), completed by cross sectional epidemiological studies. Thanks to this programme high risk groups of population, high risk places and high risk activities have been identified. These observations will be used to plan national prevention programmes on AIDS.
The authors submit a simplified sample survey methodology designed to evaluate prevalence rates of leprosy. The system proposed uses a cluster sampling technique. A cluster is a randomly selected group of households. In each household visited by the epidemiological teams all the inhabitants of the target-group are interviewed and examined. Various samples sizes are used (from 6500 to 12,000 peoples) according to the expected prevalence rate of the studied area. All the new cases detected through these surveys are notified to the National Departments in charge of leprosy programmes. Two surveys are already achieved (Equatorial Guinea, Cameroon), a third one in on the way.
The authors report the results of nine sample surveys for the evaluation of the immunization coverage program carried out in urban and rural areas in Cameroon. The halfway target of 30% is reached in urban areas and approached in rural areas. The achievement of the target (85%) will need the solution of more and more intricate problems and the participation of the whole national community.
The authors report the results of 3 sample surveys carried out in Cameroon and designed to determine the diarrhoeal morbidity, mortality and treatment rates in children under five years of age living in urban and rural areas, under different types of climate.
A severe epidemic of group A meningococcal disease occurred in the northwest part of the Central African Republic from January to March 1992. The outbreak affected a large and densely populated area, with a poor road network, located 400 kilometers south of the classical meningitis belt. An initial selective vaccination campaign was carried out by the national health care service. As the epidemic was continuing, the national authorities asked for international assistance. The French participated by sending Bioforce, a medical task force designed by the Ministry of Defense, with the financial support of the Ministry of Cooperation. Neisseria meningitidis strains were isolated and identified within 36 hours by the Bioforce field laboratory. Strains from 24 patients were sent to the Pasteur Institute in Paris (Neisseria Unit) for serotyping, testing of antibiotic susceptibility, and multilocus enzyme electrophoresis. With one exception, all strains had formula A:4:P1.9. By an initial rapid assessment, the limits of the affected area and populations were determined. The weekly incidence rates observed in different areas varied within a range of 3 to 10 cases per 1,000, with fatality rates from 20 to 30 cases per 100. The spread of the epidemic was stopped by a mass vaccination campaign, which targeted the entire population (200,000 immunizations) of the affected area. The case fatality rate could not be reduced below 15%, despite antimicrobial treatments implemented as soon as possible. The optimal treatment was the standard single intramuscular injection of oily chloramphenicol. The predictive values of clinical symptoms were calculated. The efficacy of vaccination was estimated by comparison of the percentage of people immunized and the proportion of those vaccinated people who developed meningitis identified during the 3 weeks following the mass vaccination campaign. The efficacy varied between 93 to 95% according to the place. The typical weekly incidence rate of 1 case per 1,000 is not a relevant threshold to sufficiently and immediately detect a meningitis outbreak and needs to be reconsidered.
Simian virus 40 (SV40) has been introduced into the human population with contaminated polio vaccines between 1955 and 1963. Previous research conducted by southern blot hybridization and recent analysis by PCR have shown the presence of SW0 sequences in human brain tumors, mesotheliomas and osteosarcomas as well as in normal tissues such as blood and sperm fluids. SV40 RNA and T antigen were detected in the same tissues. All the samples were coinfected by BK Virus (BKV), suggesting that BKV may have a helper function for SV40 replication in human cells. The presence of SV40 in human tumors suggests that the virus may be a cofactor in the etiopathogenesis of human neoplasia. In addition, blood and semen may represent the vectors for transmission of SV40 by horizontal infection in the human population.