Evaluation des risques de réémergence de l'épidémie du virus Chikungunya dans la vallée du Monastère de Mont Ngafula, RD Congo

Contexte et objectif. L'épidémie à virus Chikungunya est émergente, invalidante et mortelle qui sévi partout. Le virus Chikungunya est transmis à l'homme par la piqûre des insectes infectés du genre Aedes. A Kinshasa, le récent épisode de l'épidémie remonte à 4 années. L'objectif de la présente étude a été d'évaluer les risques de réémergence de l'épidémie du virus Chikungunya à Kinshasa Mont Ngafula. Méthodes. Il s'agissait d'une étude transversale menée à Mont Ngafula, dans laquelle 4 sites ont été sélectionnés à l'aide d'un plan d'échantillonnage à plusieurs degrés du 1er juin au 30 août 2021. Les larves et les nymphes des insectes ont constitué le matériel biologique de l'étude. Des variables environnementales (Température, pH, turbidité, Conductivité et Saturation en oxygène) ont été recueillies dans les gîtes larvaires. Une analyse de régression logistique multivariée a été effectuée pour identifier les prédicteurs de la densité des gîtes larvaires. Résultats. 400 ménages et 738 gîtes larvaires ont été explorés. Les indices entomologiques, indice récipient (IR), indice maison (IM) et indice de Breteau (IB) évalués étaient supérieurs aux critères et normes de l'OMS. La saturation en oxygène, la turbidité et la conductivité se sont avérées significativement associées à la densité des gîtes larvaires. Conclusion. Les risques de réémergence de l'épidémie de Chikungunya à Kinshasa sont réels. Une surveillance entomologique est nécessaire pour mettre en place des mesures de prévention et de contrôle de santé publique.

Prevalence of human myiasis infestation among primary school pupils in Ayamelum Local Government Area, Anambra State South- Eastern Nigeria

Infestation of live human or other vertebrate host with true fly larvae belonging to the class Hexapod, order Dipterans is called Myiasis. A prospective prevalence study of human myiasis among primary school pupils in Ayamelum Local Government Area (LGA) of Anambra State was carried out from October 2015 to September 2016. The mean age of the subject was 7.3±1.9. Of the 3,250 pupils who participated in the study from eight towns that constitute the LGA 287 (8.8%) pupils were positive to myiasis. Cordylobia anthropophaga (tumbu fly) was found to be the predominating fly species involved in the myiasis infestation implicated in furuncular myiasis with 92.6% of the pupils. Other species such as Cochliomyia hominivorax /Phaenicia sericata (blow fly) and Musca domestica (house fly) were also found infesting the wounds with 3.3% and 4.1% pupils respectively. The prevalence pattern also varies considerably in 8 towns that constituted the LGA with location 2 with highest: 6.1% locations 5&7 lowest with 3.2% and 1.9% respectively. Age showed significant association with pupils ≤6years most susceptible p <0.01. The highest infestation rate was recorded between April to July usually the rainy season. The most frequently infested body regions were the scalp of the head, buttocks and thigh. Ignorance, filthy environment, unkempt little children, and dirty hygienic practices are major predisposing factors of myiasis infestation among primary school pupils in the area under study

Comparative toxicity effect of bush tea leaves (Hyptis suaveolens) and orange peel (Citrus sinensis) oil extract on larvae of the yellow fever mosquito Aedes aegypti

The ethanolic extracts of the orange peel (Citrus sinensis) and bush tea leaves (Hyptis suaveolens) were compared for their toxicity effect on the larvae of the yellow fever mosquito Aedes aegypti collected from disused tyres beside College of Natural Sciences building University of Agriculture, Abeokuta, Nigeria. Eight graded concentrations, 0.9ppm, 0.8ppm, 0.7ppm, 0.6ppm, 0.5ppm, 0.4ppm, 0.3ppm and 0.2ppm of both plant extracts were tested on the larvae. The mean lethal dose LD10, was 0.15 ppm for C. sinensis, 0.01 for H. suaveolens, while LD50 for C. sinensis was 0.4ppm, H.suaveolens 0.60ppm and LD90 for C. sinensis was 0.9ppm and H.suaveolens was 1.45ppm. LD10 for the control 0.65ppm, LD50 0.9ppm and LD90 2.0 ppm. The extract of C. sinensis peel caused higher mortality rate at concentrations 0.8ppm (95%) and 0.3ppm (90%) of the larvae while the extract of H. suaveolens caused high mortality rate on the larvae at concentrations of 0.9ppm (80%) and 0.3ppm (80%). Significant differences were observed between untreated and treated larvae (exposed to either of the extract) at the various concentrations (P< 0.05)

Revue du genre Coquilletidia (Diptera : Culicidae) a Madagascar et description de la larve de Cq. grandidieri (Blanchard; 1905)

"Review of the genus Coquilletidia (Diptera : Culicidae) in Madagascar and description of the larva of Cq.grandidieri (Blanchard; 1905)"" : The genus Coquilletidia includes some of the mosquitoes involved in the transmission of numerous arbovirosis. Adults are locally abundant and very aggressive for men. In Madagascar; thus genus concerns 3 species among which 2 are endemic and had not been described at larval stage this far. The authors describe a single larva of Coquilletidia collected at Ankazobe in the Middle West of Madagascar; at an altitude of 1200 meters.The geographical distribution of Coquilletidia adults collected in various bio-climatic zones in Madagascar; combined with observed morphological characters; permit us to attribute this larva to Cq. grandidieri."

Vector elimination project: Progress report (1999 - 2000)

A combination of factors unique to Bioko (Republic of Equatorial Guinea) renders it possible to stop onchocerciasis transmission pernanently through the elimination of the local vector, a member of the Simulium damnosum complex. These factors include its geographical isolation, its small size, the very few rivers that will require treatment and even for those that do, the short stretches that have to be treated, the close proximity of rivers that need treatment and the very low river discharges which means that relatively small quantities of insecticide will be needed. These facts were established by a study funded by WHO/TDR in 1996 and the subsequent project was adopted for implementation by APOC. Three main activities were initiated in the first one and half years (the period under review) and these were; development of the necessary skills and capacity in Bioko, pre-control entomological data collection and an impact assessment studies of the effect of Temephos on non-target aquatic fauna of Bioko. Six Guineans received training in all aspects of entomological data collection foronchocerciasis. control and are now competent enough to conduct these exercises with very minimum supervision. The data collection was initiated in April 1999 at four sites located on the most important rivers in the northem inhabited part of the island. Regular fly catches and dissections have been carried out since then with each site being visited once each week. A total of 21,713 flies were caught during 199 visits and 16,988 of them were dissected to find Onchocerca volvulus infections. When the data was analysed according to sites, it revealed that biting was intense throughout the period at all sites. The highest annual biting rate (ABR) was 60,698 bites/person/year recorded at Barleycorn on R. Apu and the lowest ABR recorded was 21,849 at Sampaca (R. Sampaca). Periodicity in fly densities were observed with most biting occurring during the rainy season when the rivers are as expected most productive. With regards to transmission the highest recorded index of annual transmission (i.e., ATP) of 1,447 infective larvae/person/year was at Sampaca and the lowest was 385 at Balacha de Riaba. These figures are low if considered that similar values are recorded monthly at sites on mainland West Africa which have had no history ofonchocerciasis control and but have similar biting rates. Bioko has a 10 year history of ivermectin distribution and this was thought to be the reason for the observed low transmission. Seasonal variation in transmission was also observed with most transmission occurring in the dry season, which is also not surprising because of increased proportions of old flies in S. damnosuz populations during this season. The environmental impact assessment studies also provided baseline information of densities and diversity of fish, prawns and macro- invertebrate fauna of Bioko. The main findings were that these were poor if compared to the richness of the fauna of rivers on the mainland. The major conclusions drawn from the studies on the impact of Temephos were that neither mortalities nor harm to fish and prawns should be anticipated at the treatment dosages envisaged and that the overall impact on the macro- invertebrate fauna was not that high as to prevent their recovery after treatment. Ground treatment of rivers is planned for the coming 2000 - 2001 dry season. The main aim is to establish the extent to which it could complement any aerial larviciding operations. The detailed planning has been completed (the plan of action is attached to this report). All the rivers on the island have been coded, the treatment points have been identified, treatment maps have been prepared and other activities, including procurement of spraying equipment, insecticide, etc have been initiated. A strategic meeting at APOC/FIQ is planned after the ground larviciding operation for evaluation and to decide on the future direction of the project.

Onchocerciasis control on the island of Bioko (Republic of Equatorial Guinea) by vector elimination: Environnemental impact assessment (EIA) part 2c macro invertebrate indicator species

A literature search has established that the freshwater macro-invertebrate fauna ofBioko is extremely poorly studied and that relatively few species of freshwater insects have been recorded from the island (Appendix 1). Nevertheless, it is apparent from this searc[ and from insects collected on the island during the present study, that the ocp identification manual to aquatic inseas from the Ivory coast @ejoux et al., lggl)and the standard recording form 5620 are adequate for family level recording of specimens collected on the island because all families known from Bioko are covered. There are genera of aquatic insects which are found on Bioko and are not covered, but this is unlikely to seriously distort estimates of community structurq for which they are designed. l'2' The impact of the inseaicide Temephos, used to eradicate Sirrulium dannowms.l. the vector of onchoceriasis, on chironomidae (non-biting midges) genera and odonata (dragonflies) species on three streams on Bioko has been investigated as part of an environmental impaa assessment. 1'3' Adult and larval odonata and larval Chironomidae were surveyed throu-ehout Bioko between 23 Marchand 9 April 1999 to establish the distribution ofthese groups and to indicate whether recolonisation oftreated strezmrs from untreated refugia would be possible to re-establish any non-target ta:ra that were eliminated following rhe Simuliumeradication progriunme.l'4' Treatment of all three trial sfeams with Temephos had an adverse effect on the chironomid fauna with an elimination of up 5u/o of thegenera at sites immediately downstream ofthe treaunent point. Insufficient nurnbers of odonata larvae were present in the samples to draw meaningful conclusions about the direa impact ofthe insecticide on the odonate fauna. However, if the insecticide causes a general reduction in abundance and biodiversity of aquatic macro- invertebrates, the odonate fauna could be expected to decline within a few weeks due to a shortage ofprey l'5 Twenty-five species of Odonata were recorded during the present survey, including six species not previously found in Bioko. The total number of odonata species now known from the island is 48 including one species (Trithemis hartwigt)and one subspecies (Chtorocypha cancellata insulua)that are cunently thought to be endernic. Trithemis hartwigr was not collected during the current survey but has previously only been recorded in the highland region around Moca. Chloruyplw cancellaninsalqwwas collected from several lowland streams during the present survey The dragonfly fauna has two elements, an upland element which includes species that occur above 1000 m only, and a lowland element including several species that do not occur above 500 m. Only three species occurred in both these faunistic elements, but there was a transitional fauna at 600 m that included a few species from each elernent. Much ofthe adult dragonfly fauna is probably seasonal in occurrence and so was not recorded during this brief survey. Certain Libellulidae probably migrate to Bioko from mainland Africa to breed in temporary pools during the wet se.$on. ffis migration us likely to be wind assisted. 1.9. Downstream recolonisation by Odonata of streams treated with inseAicide below 1000 m will not occur since upland strearns do not act as refugia for most ofthe lowland odonate fauna. However, if some permanently flowing lowland sffeams are left untreated these could act as refugia for the lowland fauna. Simultaneous inseaicide fieament of the lowland sections of all rivers on Bioko is likely to result in the elimination of a significant proportion ofthe dragonfly fauna on the island, although recolonisation by some species from the African mainland might be possible over time. The chironomid fauna appeared to be fairly uniform in lowland rivers but samples from the high altitude site included four tu

Croissance des larves de Culicidae a Kinshasa (Zaire) : influence physico-chimique des principaux gites de reproduction

Cette etude experimentale a porte sur les principaux gites permanents de reproduction des moustiques representes par les neuf plus importants cours d'eau drainant la ville de Kinshasa. La culture in vitro des larves d'Anopheles gambiae s.l. et de Culex quinquefasciatus a permis d'etudier leur croissance dans differents echantillons d'eau preleves dans ces gites. Les resultats ont montre que la croissance des larves de moustiques depend des conditions physico-chimiques du milieu de culture; reflet des conditions physico-chimiques qui regnent dans l'environnement draine par les collections d'eau etudiees. L'analyse multivariee a permis de caracteriser cinq profils physico-chimiques. Il existe des gites de reproduction plus favorable que d'autres; c'est les cas notamment des mares a vegetation aux eaux propres et ensoleillees qui offrent les meilleures conditions de survie et de croissance aussi bien pour les Anopheles que pour les Culex par rapport aux autres gites etudies. Quel que soit le profil physico-chimique du gite considere; le taux d'emergence des images pour le Culex s'est avere significativement plus eleve que celui des Anopheles; une larve de Culex a presente une chance sur deux de se transformer en image contre une chance sur trois pour une larve d'Anopheles. Cette difference est due au taux de mortalite relativement eleve des larves d'Anopheles par rapport aux larves de Culex durant la premiere semaine d'observation