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Four different alumina powders, from European and Japanese sources having similar particle size (350–700 nm) were used for the fabrication of nanocomposites. They were compared in terms of green properties, sintering behaviour, microstructure and mechanical properties. The processing route used (attrition milling and freeze-drying) leads to a reduction in green density of the processed aluminas and composites compared to the as-received alumina. All powders had similar green properties except one, which contained a binder from the manufacturer. The presence of this binder led to the formation of hard agglomerates. In this case the pressing did not eliminate, totally, the inter-agglomerate pores, leading to an incomplete sintering. Calcining the powder to remove the binder resulted in similar pressing and sintering behaviour to the other powders and densities >99% were achieved at 1750 °C by pressureless sintering. All the composites exhibited similar microstructures (matrix grain size ∼3 μm) and elastic properties, hardness and fracture toughness. A finer matrix microstructure could be obtained with one of the European powders which achieved ∼99% density at 1700 °C. The presence of 5 vol.% SiC resulted in a mean grain size of ∼2 μm for the alumina matrix compared with 13.9 μm for a monolithic alumina prepared under identical conditions. [Copyright &y& Elsevier]

From 1975, epidemiological studies on arboviral diseases, conducted in New Caledonia, Vanuatu, Wallis and Horne Islands, have shown that 11 species of mosquitoes may harbour viruses in natural conditions. Virus isolations were attempted from 1,025 pools of Culicidae totalizing 32,182 individuals belonging to 5 genera and 21 species. Viral infections have been demonstrated in 76 pools (7.4%). The species harbouring viruses were: Aedes aegypti, Ae. alternans, Ae. notoscriptus, Ae. vexans, Ae. vigilax, Culex annulirostris, C. bitaeniorhynchus, C. iyengari, Culex pipiens quinquefasciatus, Coquillettidia xanthogaster. Among the strains definitively identified, dengue 1 virus was recovered from Ae. aegypti, Ae. polynesiensis, Ae. vigilax, dengue 4 virus was obtained from Ae. aegypti, Ae. vigilax, C. xanthogaster, C. annulirostris. Ross River virus was identified in Ae. vigilax and C. quinquefasciatus. The infected mosquitoes originated from New Cadedonia, Vanuatu (Aoba), Wallis and Horne Islands.

In a test area (suburbs of Nouméa), a survey on acute infantile gastro-enteritis showed an annual incidence of 2.2% and a hospitalization rate of 27.5%. The 0 to 23 months age group was the most exposed. The factors of severity were: a low age, a high frequency of liquid stool, vomits, fever and associated acute respiratory infection. The etiologic diagnosis was possible in 76% of cases: 49.5% enteropathogens (22% bacteria, 27.5% viruses), 26.5% non-intestinal infections. The asymptomatic carriers were 11.5% for bacteria and 27.4% for viruses. In regard to epidemiology, the housing hygiene, the potable water supply and the presence of suitable water closet were over 90%. On the contrary, the individual hygiene was neglected, especially the hand washing. The pathogens are transmitted by the dirty hands of asymptomatic carriers. Mass media campaigns and health education of parents and children are the recommended prophylactic measures.

Eight viral isolates were recovered from Eidolon helvum bats collected in Nigeria and Cameroon in 1971 and from the Central African Republic in 1974. Subsequent studies showed that the agents from the three countries were similar and were strains of a new virus of the Orbivirus genus, family Reoviridae. This new virus was characterized with respect to its sensitivity to lipid solvents and to pH, its relative size and morphology by electron microscopy, its effect on mice experimentally infected by various routes, the histopathology found in infected mice, and its antigenic relationship or lack of a relationship to other known orbiviruses.

After an outbreak in 1956, poliomyelitis appears to get a sporadic development. Consequently, it has not been a major medical concern. In 1982, 5 cases of paralytic manifestations due to a polio virus of type 1 underlined the relationship between this reappearance of the disease, some neglecting in mass vaccination and some deficiency in sanitary conditions of the surroundings. A serologic monitoring, complementary to that survey, has been conducted up to 1984. It has shown that, in a number of zones of the territory, a natural immunization has appeared quickly. This immunization is of the same type that in some underdeveloped tropical countries: at 6, 93,3% of the children present protective antibodies against 1 type of virus, 40% against 2 types and 6,7% against the 3 types. Vaccination with non-active vaccine, adopted because the risks of interference linked to the frequency of excretion of the enteroviruses, is efficient. After a primo-vaccination followed by a booster dose one year later, sero-conversion ranges from 95,3% to 100% for type 1, 83,3% to 96,5% for type 2, 75% to 84,9% for type 3. On the other hand, sero-conversion observed one month after the second vaccination appeared to be unsatisfactory to lighter the vaccinal time-table.

The authors give results of a survey of arboviruses isolated from mosquitoes in the neighborhood of Yaoundé, Southern Cameroon, from 1964 to 1972. During this period of nine years 127.520 female mosquitoes including at least 72 species were collected and processed for attempt of virus isolation. 55 strains belonging to 12 viral types were recovered from at least 19 species of mosquitoes. The appearance of different viruses over the years was quite intermittent. A possible reason for this is the need for viruses to move in search of susceptible vertebrate hosts. There was not definite evidence of vector host specificity except likely for Anopheles gambiae s. l. as a vector of Tataguine. However, among the more infected species, some ones show by their host preferences they could be true vectors of the viruses isolated from them.

The present study permits to set up the following conclusions: A) The hygienic level of New-Caledonia and Dependences, concerning both running water feeding and installation of water-closets inside housings, is extremely disparate according to the parishes. On that account, the hygienic level is low on the East Coast of the "Grande-Terre" and in the islands. Most of European inhabitants are found in the district of Noumea whereas Melanesians live in tribes mainly on the East Coast and in the islands. Therefore, there is a real difference of hygienic level between the two main ethnic groups.

Five cases of paralytic poliomyelitis were noticed between August and November 1982 in the French Territory of New-Caledonia. An epidemiological study allowed to have a better apprehension on the coming back of poliovirus in the South Pacific where, for the past ten years, except in Papua New Guinea which remained an endemic zone, not a single case of poliomyelitis has been declared to the World Health Organization.

A two year study, from 1981 to 1982, has been conducted in New Caledonia to estimate the importance of rotavirus infections in children with gastroenteritis. On 497 stool specimens, 71 (14.2%) were found positive by using ELISA test to demonstrate a rotavirus infection. Male children and age group six months-two years appeared to be the most affected. Rotavirus infections were more numerous during the dry fresh season (August-November). Mixed infections with enteroviruses or enterobacteriae were found respectively in 27.8% and 9.7% of the stool specimens. Enterotoxigenic strains of Escherichia coli were also found in 3 cases. Serological conversions were noted in 18 paired sera, obtained from 159 patients (11%).

The authors report the first two cases of rhinosporidiosis in Cameroon. The patients were females from Cameroon southern-center or littoral areas, damp regions, and presented a conjunctival localization of this mycosis.

Authors describe ten new cases of Entomophthoromycosis in Cameroon. In four cases of subcutaneous phycomycosis, Basidiobolus meristoporus was isolated in one case. In six cases of rhino-entomophthoromycosis, we have obtained by culture two Basidiobolus meristoporus and one Entomophthora coronata. In Cameroon, rhino-entomophthoromycosis may be caused by the two species Basidiobolus meristoporus and Entomophthora coronata.

After imported cases, a dengue outbreak, caused by type 4 virus, affected 11 per cent of the habitants of Thio, New Caledonia. Distribution of cases by sex, by ethnic and age group, by locality and by week is established on cases confirmed by serology and/or by virus isolation. Clinical aspect was classical but liver and digestive tract of patients were frequently affected. Five haemorrhagic forms were observed. Aedes aegypti was found in each visited house; pooled specimens were found infected by type 4 virus.

During an outbreak of arboviral diseases in the South-West Pacific islands, from 1979 to 1980, patients sera examined in New Caledonia revealed 43 cases of epidemic polyarthritis due to Ross River virus. Viral strains were obtained from 16 of these patients. After isolation of the virus in newborn mice, the inoculation of C6/36, PS-EK and Vero cells allowed the identification of these strains by hemagglutination inhibition and complement fixation tests. This was the first time that cases of polyarthritis caused by RR virus were observed in New Caledonia, Vanuatu, Wallis and Futuna.

The screening of different ethnic groups who live in the same natural system have enabled the authors to study interaction between genetic and environmental factors as a part of etiology of diabetes mellitus. In New Caledonian country areas, the prevalences of glucose tolerance abnormality (GTA) and diabetes mellitus (DM) have been higher with people of polynesian descent than with Melanesians. GTA 7.6 p. ct. versus 5.1 p. ct. DM 6.5 p. ct. versus 2.2 p. ct. The prevalence of these combined diseases have been 14 p. ct. with the Polynesians and 7.2 p. ct. with Melanesians. These two ethnic groups have shown mean ages and obesity rates similar enough to lead the authors to deny these two factors a major part in the difference between the ethnic prevalences of DM. Besides, the mean plasmatic glycemia two hours after a dose of glucose and the relative risk of DM and GTA according to age and obesity rate have shown that the slight differences between these groups are not involved in the different prevalences of DM. This inter-ethnic difference may be due to genetic factors. However, some environment linked factors besides obesity (such as diet and daily life activity) may share a major part in this difference.

The Expanded Programme on Immunization (EPI) was established by the World Health Assembly in 1974. The EPI goal is to reduce morbidity and mortality by making immunization services available for all children of the world by 1990. General considerations on EPI vaccines, their security and efficacy, the age of administration and the number and spacing of doses are discussed. Vaccine administration, including strategies and tactics, cost effectiveness, immunization coverage and disease surveillance are reviewed.

The titration of rabbit anti-Escherichia coli heat-labile enterotoxin antibodies by an immunosorbent assay (ELISA) generally uses a GM1 coating step to lend specificity to the ELISA reaction at a time when the method is tempered by a lack of purified E. coli toxin. We have developed an adsorption method of the toxin to the polystyrene in order to simplify the technique. Three different immunosorbent preparations were tested to determine which of them yielded the most sensitive results.

A strain of Mokola virus has been isolated in Cameroon from a shrew (Crocidura sp.). In Nigeria, where the virus was isolated for the first time, two human cases with one death were reported. The possibility of transmission of this virus by the bite of an arthropod is discussed.

Islands of the south-west Pacific area belong to the melanesian group, excepted Niue, Tonga, Wallis and Futuna which are polynesian. Through New Guinea, there is a geographic relation to the eastern part of Australia, rich of 42 arbovirus types. Dengue and Ross River fever are the most important arboviral diseases in the region; both affect islanders after introduction of virus by travellers to localities where efficient vectors are present. Dengue types 1, 2 and 4 were isolated from man and from mosquitoes in this area. Successive outbreaks, transmitted by Aedes aegypti or by Ae. polynesiensis, resulted in thousands of cases with a few fatal hemorrhagic forms. Ross River virus, responsible of epidemic polyarthritis, evaded in 1979, from Australia to Fidji, Wallis, Futuna and New Caledonia. Suspected vectors are Aedes vigilax and Culex annulirostris. Aedes aegypti and Ae. polynesiensis are also possible carriers. Murray Valley encephalitis virus caused severe outbreaks in Australia and fatal cases in New Guinea; it is a possible invader when Culex annulirostris is abundant. Expansion of arboviral diseases is a major epidemiological problem in south-west Pacific islands. Research work on pathogeny and vectors control must be intensified in this area.

Enterotoxigenic Escherichia coli (ETEC) of infant origin from the Popular Democratic Republic Lao were characterized with respect to there 0 serogroups, biotypes, anti-bioresistances, fimbrial antigens and types of enterotoxins produced. Enterotoxin production was determined by the suckling mice assay, competitive GM1-erythroassay, and cell cultures (CHOK1 and Y1). The presence of genes encoding for the enterotoxins was determined by colony hybridization by using radioactive DNA probes. Profile plasmids from ETEC strains were studied. The plasmids encoding for heat-labile enterotoxin were studied with an acetyl-aminofluorene modified probe.

During an outbreak occuring in Futuna (Horne Islands) from October 1976 to January 1977, II strains quite similar to dengue virus type I were isolated from blood of patients in acute phase. Immunitary responses were noted on 8/12 paired sera submitted to IH test; 4/17 serum samples showed antibody titer presumptive of a recent infection. Entomological survey gave evidence that virus was transmitted by Aedes polynesiensis and confirmed that Futuna is free of A.E. aegypti; other species found were: Culex annulirostris, C. pipiens fatigans, C. sitiens. A viral strain was isolated from Ae. polynesiensis only.