Quantifying and characterizing hourly human exposure to malaria vectors bites to address residual malaria transmission during dry and rainy seasons in rural Southwest Burkina Faso.

BACKGROUND: To sustain the efficacy of malaria vector control, the World Health Organization (WHO) recommends the combination of effective tools. Before designing and implementing additional strategies in any setting, it is critical to monitor or predict when and where transmission occurs. However, to date, very few studies have quantified the behavioural interactions between humans and Anopheles vectors in Africa. Here, we characterized residual transmission in a rural area of Burkina Faso where long lasting insecticidal nets (LLIN) are widely used. METHODS: We analysed data on both human and malaria vectors behaviours from 27 villages to measure hourly human exposure to vector bites in dry and rainy seasons using a mathematical model. We estimated the protective efficacy of LLINs and characterised where (indoors vs. outdoors) and when both LLIN users and non-users were exposed to vector bites. RESULTS: The percentage of the population who declared sleeping under a LLIN the previous night was very high regardless of the season, with an average LLIN use ranging from 92.43 to 99.89%. The use of LLIN provided > 80% protection against exposure to vector bites. The proportion of exposure for LLIN users was 29-57% after 05:00 and 0.05-12% before 20:00. More than 80% of exposure occurred indoors for LLIN users and the estimate reached 90% for children under 5 years old in the dry cold season. CONCLUSIONS: LLINs are predicted to provide considerable protection against exposure to malaria vector bites in the rural area of Diébougou. Nevertheless, LLIN users are still exposed to vector bites which occurred mostly indoors in late morning. Therefore, complementary strategies targeting indoor biting vectors in combination with LLIN are expected to be the most efficient to control residual malaria transmission in this area.

Evaluating the impact of screening plus eave tubes on malaria transmission compared to current best practice in central Côte d'Ivoire: a two armed cluster randomized controlled trial.

BACKGROUND: Access to long-lasting insecticidal nets (LLINs) has increased and malaria has decreased globally, but malaria transmission remains high in parts of sub-Saharan Africa and insecticide resistance threatens current progress. Eave tubes are a new tool for the targeted delivery of insecticides against mosquitoes attempting to enter houses. The primary objective of this trial is to test whether screening plus eave tubes (SET) provides protection against malaria, on top of universal coverage with LLINs in an area of intense pyrethroid resistance. The trial will also assess acceptability and cost-effectiveness of the intervention. METHODS/DESIGN: A two-armed, cluster randomized controlled trial will be conducted to evaluate the effect of SET on clinical malaria incidence in children living in central Côte d'Ivoire. Forty villages will be selected based on population size and the proportion of houses suitable for modification with SET. Using restricted randomization, half the villages will be assigned to the treatment arm (SET + LLINs) and the remainder will be assigned to the control arm (LLINs only). In both arms, LLINs will be distributed and in the treatment arm, householders will be offered SET. Fifty children aged six months to eight years old will be enrolled from randomly selected households in each of the 40 villages. Cohorts will be cleared of malaria parasites at the start of the study and one year after recruitment, and will be monitored for clinical malaria case incidence by active case detection over two years. Mosquito densities will be assessed using CDC light traps and human landing catches and a subset of Anopheles mosquitoes will be examined for parity status and tested for sporozoite infection. Acceptability of SET will be monitored using surveys and focus groups. Cost-effectiveness analysis will measure the incremental cost per case averted and per disability-adjusted life year (DALY) averted of adding SET to LLINs. Economic and financial costs will be estimated from societal and provider perspective using standard economic evaluation methods. DISCUSSION: This study will be the first evaluation of the epidemiological impact of SET. Trial findings will show whether SET is a viable, cost-effective technology for malaria control in Côte d'Ivoire and possibly elsewhere. TRIAL REGISTRATION: ISRCTN18145556 , registered on 01 February 2017 - retrospectively registered.

Human meningitis due to Streptococcus suis in Lomé, Togo: a case report.

BACKGROUND: Streptococcus suis is a zoonotic pathogen which represents the leading cause of meningitis in Southeast Asia and an emerging pathogen in the Western world, the main risk factor for infection being contact with pigs. In Africa, the prevalence of S. suis infections in swine and humans is largely unrecognized, with only one recent report of a limited case series. CASE PRESENTATION: We describe a human case of meningitis due to S. suis in a 32-year-old man living in Togo. The patient had no particular medical history and no risk factors for immunodeficiency but reported regular contact with pork products. Using specific immunological and molecular methods, we characterized the isolate as S. suis serotype 2, ST1, one the most prevalent and virulent clone worldwide. The outcome was favorable after one week of adapted antibiotic therapy but the patient was left with severe hearing disorders. CONCLUSIONS: This work highlights the emergence of this pathogen in Africa and reinforces the need for accurate epidemiological and surveillance studies of S. suis infections and for educating clinicians and exposed groups in non-endemic countries.

Ruptured subcapsular liver hematoma and pregnancy: a rare complication of severe preeclampsia: a report of a case discovered fortuitously at the Maternity Teaching Hospital of Cocody.

We report a case of spontaneous rupture of a subcapsular hematoma of the liver (SHL). It was discovered incidentally at the end of an emergency exploratory laparotomy performed due to unexplained hemoperitoneum with hypovolemic shock which occurred with severe preeclampsia. Diagnosis and therapeutic management are very difficult in sub-Saharan Africa due in part to the limitations and lack of medical equipment. The prognosis is usually marked by the death of the patient, as in our case. Through this clinical observation we wanted to show the interest in performing a liver ultrasound at any level of preeclampsia to detect liver abnormalities as soon as possible.

[Bilateral simultaneous central retinal artery occlusion revealing giant cell arteritis]. / Occlusion bilaterale et simultanee de l'artere centrale de la retine revelatrice d'une maladie de Horton.

AIM: To point out the importance of the early diagnosis of giant cell arteritis (GCA) (Horton's disease). MATERIALS AND METHODS: a case report of a sudden bilateral blindness that had revealed GCA. CASE REPORT: A 68-year old female patient with a history of elevated blood pressure and diabetes mellitus type 2, was examined in emergency for a right painful headache developed one week previously. In ophthalmological examination, her BCVA was 0.9 and P2 in both eyes. Diagnosis of Horton's disease was not initially done in spite of elevated erythrocytes sedimentation rate (ESR) at 30 mm, protein C reactive (CRP) at 19 mg/l. The patient consulted seven weeks later in emergency for a sudden bilateral blindness associated with severe headache, recent asthenia, and limping of the lower jaw. At that time, visual acuity was reduced to light perception in both eyes whereas ophthalmoscopy revealed a bilateral central retinal artery occlusion (CRAO). ESR was 74 mm and CRP 233 mg/I. Temporal artery biopsy confirmed the diagnosis of GCA. The patient was treated with systemic steroids without visual recovery. CONCLUSION: This case outlines the importance of the early diagnosis of GCA in order to make possible to start treatment before the occurrence of irreversible complications.

[Recurrences of precancerous lesions after conservative treatment: Operational results after a decade in Abidjan]. / Récidives des lésions précancéreuses après traitement conservateur : résultats opérationnels après une décennie à Abidjan.

OBJECTIVES: There remains a significant risk of recurrence of intraepithelial neoplasia regardless of the type of conservative treatment. The aim's work is to assess this rate. METHODS: All women's consenting who had received conservative treatment at the sites identified since for more than 12 months were included in this multicenter cross-sectional study. The outcome measure was a recurrence of precancerous lesions of the cervix during visual inspection with acetic acid performed by a single practitioner to limit interobserver variability. Data collection and analysis were done on the Stata 13 software. We performed an univariate then multivariate analysis with logistic regression. RESULTS: Two hundred and seventy-nine participated in this study with an average age of 37.44 (σ=7.31 years). A total of 52.33% were HIV positive. Moreover, 63.44% were treated by cryotherapy versus 36.66% by loop electrosurgical excision procedure. The overall prevalence of recurrences was 8.96%. Multivariate analysis with logistic regression concluded that the risk of recurrence was 5.72 times (OR=1.69-19.29; P=0.005) higher with cryotherapy and 2.85 times higher (OR=1.04-7.82; P=0.042) in women with HIV. CONCLUSION: The risk of recurrence is proportionally high with cryotherapy and HIV status. This suggests that an adaptation of the strict monitoring protocols to our African context due to the lack of cytocolposcopic logistical resources.

Evaluation of Yahe® and Panda® 2.0 long-lasting insecticidal nets against wild pyrethroid-resistant Anopheles gambiae s.l. from Côte d'Ivoire: an experimental hut trial.

BACKGROUND: Long-lasting insecticidal nets (LLINs) have played an important role in reducing the global malaria burden since 2000. They are a core prevention tool used widely by people at risk of malaria. The Vector Control Prequalification mechanism of the Word Health Organization (WHO-Vector Control PQ) established the testing and evaluation guidelines for LLINs before registration for public use. In the present study, two new brands of deltamethrin-impregnated nets (Yahe® LN and Panda® Net 2.0) were evaluated in an experimental hut against wild pyrethroid-resistant Anopheles gambiae s.l. in M'Bé nearby Bouaké, central Côte d'Ivoire. METHODS: The performance of Yahe® LN and Panda® Net 2.0 was compared with that of PermaNet 2.0, conventionally treated nets (CTN), and untreated net to assess the blood-feeding inhibition, deterrence, induced exophily, and mortality. RESULTS: Cone bioassay results showed that Panda® Net 2.0, PermaNet 2.0 and Yahe® LN (both unwashed and washed 20 times) induced > 95% knockdown or > 80% mortality of the susceptible Anopheles gambiae Kisumu strain. With the pyrethroid-resistant M'Bé strain, mortality rate for all treated nets did not exceed 70%. There was a significant reduction in entry and blood feeding (p < 0.05) and an increase in exophily and mortality rates (p < 0.05) with all treatments compared to untreated nets, except the CTNs. However, the personal protection induced by these treated nets decreased significantly after 20 washes. The performance of Panda® Net 2.0 was equal to PermaNet® 2.0 in terms of inhibiting blood feeding, but better than PermaNet® 2.0 in terms of mortality. CONCLUSION: This study showed that Yahe® LN and Panda® Net 2.0 met the WHO Pesticide Evaluation Scheme (WHOPES) criteria to undergo phase III trial at the community level. Due to an increasing spread and development of pyrethroid resistance in malaria vectors, control of malaria transmission must evolve into an integrated vector management relying on a large variety of efficient control tools.

[Management of breast cancer in Abidjan: A single center experience]. / Expérience africaine monocentrique de la prise en charge personnalisée des cancers du sein à Abidjan : défis et perspectives.

AIM: To present the results of the personalized care of Ivorian women suffering from breast cancer since the advent of immunohistochemistry in Côte d'Ivoire. METHODS: We carried out a single-center retrospective study at the Yopougon university hospital from January 2014 to December 2018. All women's breast cancer with complementary immunohistochemistry and treated at the Yopougon hospital center were selected. Standard descriptive statistical tests were used to describe patient and tumor characteristics, and univariate and multivariate analyzes were performed with a statistical significance set at a P-value of 0.05 using SPSS version 20.0. RESULTS: The mean age of women is 48.27 years, SD (11.92). 50.88 % of the tumors were hormone-dependent. The triple negative subgroup was the most represented (43.28 %) followed by luminal A (35.42 %). Conservative treatment represented 18.51 % of cases. In the univariate analysis, the risk of developing a hormone-dependent cancer is statistically significant respectively in women with an education level removed OR=1.98 (P˂0.015) and with a wealthy salary OR=1.85 (P˂0.009). On the other hand, the high level of education (OR=0.44; P˂0.005), and the well-off salary condition (OR=0.59; P˂0.024) would be protective factors for the development of triple negative breast cancer. All these factors are not significant in multivariate analysis, whether for hormone-dependent or triple negative tumors. CONCLUSION: The personalized care of breast cancer in our African context remains difficult and must take into account several medical and extra-medical parameters.

[Antimicrobial activity of Morinda morindoides on in vitro growth of vibrio cholerae in Côte d'Ivoire]. / Activité de Morinda morindoides sur la croissance in vitro du vibrion du choléra: expérimentation en Côte d'Ivoire.

Cholera is a major public health problem in developing countries. As a contribution to management of this disease, the study described herein was carried out in Côte d'Ivoire. The purpose was to evaluate the antibacterial activity of products obtained by various techniques from the leaves of Morinda morindoides on a pathogenic strain of Vibrio cholerae O:1. Morinda morindoides is a medicinal plant in the Ivorian pharmacopoeia. The products were obtained as aqueous extracts, 70% ethanolic extracts, residual extracts and a chromatographic fraction (BGG F5). All three extracts and the chromatographic fraction showed considerable in vitro antimicrobial efficacy against Vibrio cholerae O:1. The most active against in vitro growth of Vibrio cholorae O:1 was the 70% ethanolic extract with a minimal bactericidal concentration of 5 mg/ml. The antibacterial properties of this medicinal plant can be of great benefit for management of cholera.

[Cost Analysis of the Immunization Program Supportive Supervision in Côte-d'Ivoire]. / Analyse des coûts de supervision formative du programme de vaccination en Côte-d'Ivoire.

One of the major obstacles to improve the performance of immunization programs is the lack of competent health personnel. To increase the availability of qualified health personnel, the Agence de Médecine Préventive (Agency of Preventive Medicine) has set up a technical assistance focused on supportive supervision. The objective of this study is to analyze the cost of this supportive supervision in 10 health districts of Côte-d'Ivoire. The data extracted from the financial and technical reports of the supportive supervisions included personnel costs (salary, per diem), transportation, communication, office supplies, vehicle maintenance and depreciation. The analysis consisted of estimating the total cost of the supportive supervision, the total cost per item and the average cost of a supervisory visit. The conduct of 40 supportive supervision visits amounted to 44,675.12 USD. Of this amount, recurring costs were 40,112.12 USD (89.79%) and non-recurring costs were 4,563 USD (10.21%). The unit cost per supervisory visit was 1,116.88 USD. The cost of personnel was the largest cost. The total cost of the formative supervision would be reduced by 58.68% through the resort to local facilities' staff for the supervision, and the review of the useful life of the vehicles. The costs for implementing supportive supervision were acceptable in comparison to the benefits. Mastering personnel costs, optimizing the scheduling of supervision tours and frequency of visits focused on districts with the lowest EPI indicators could lead to cost savings.

Un des obstacles à l'amélioration des performances des programmes de vaccination est l'insuffisance de ressources humaines compétentes. Pour accroître la disponibilité de personnel de santé qualifié, l'Agence de médecine préventive a mis en place une assistance technique centrée sur la supervision formative. L'objectif de cette étude est d'analyser les coûts de cette supervision formative dans dix districts sanitaires de Côte-d'Ivoire à partir des données extraites des rapports techniques et financiers de supervision. L'analyse a consisté en l'estimation du coût total des supervisions, du coût total par poste et du coût moyen par visite de supervision. Les 40 visites de supervision réalisées ont coûté 44 675,12 USD dont 40 112,12 USD de coûts récurrents (89,78 %) et 4 563 USD de coûts non récurrents. Le coût par visite de supervision était de 1 116,87 USD. Le coût du personnel était le poste de coûts le plus important. Le coût total et le coût unitaire de la supervision seraient réduits de 58,68 % par l'utilisation des superviseurs locaux et des recommandations de l'OMS sur la durée de vie utile des véhicules. Les coûts de la supervision formative étaient acceptables au regard des bénéfices obtenus. La maîtrise des coûts du personnel, une programmation optimale des tournées de supervision et une fréquence des visites centrée davantage sur les districts présentant les plus faibles indicateurs du PEV pourraient favoriser des économies.

Characterization and in vitro evaluation of a vaginal gel containing Lactobacillus crispatus for the prevention of gonorrhea.

The increasing resistance of Neisseria gonorrhoeae to any current antibiotic treatment and the difficulties associated with the use of prevention means such as condom urge the need for alternative methods to prevent this sexually transmitted infection. In this work, a prevention strategy based on the use of a vaginal gel containing Lactobacilli was assessed in vitro. A Lactobacillus crispatus strain (ATCC 33197) was selected based on the published data on its ability to inhibit Neisseria gonorrhoeae. Its probiotic properties were first characterized. Then, a thermo-sensitive hydrogel containing 21.5% of poloxamer 407, 1% of sodium alginate and 9log10 CFU of Lactobacillus crispatus per gel sample (5 g) was developed. The gelation temperature and the rheological characteristics of this formulation appeared suitable for a vaginal administration. Lactobacillus crispatus was viable in the gel for six months although a large amount of the bacteria was not culturable. The ability of Lactobacillus crispatus to inhibit Neisseria gonorrhoeae was still observed with the gel. Such system, thus, appeared promising for the prevention of gonorrhea.

[A case of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) syndrome]. / Un cas clinique de syndrome d'hyperplasie neuroendocrine pulmonaire diffuse idiopathique (DIPNECH).

INTRODUCTION: DIPNECH is a strictly histological entity according to the WHO 2015 classification and is considered to be at pre-neoplastic risk. It has been proposed that DIPNECH syndrome should be used to describe patients have clinical symptoms, an obstructive ventilatory disorder and compatible radiological abnormalities. The diagnosis is histological and usually based on a surgical lung biopsy. CASE REPORT: We report the case of a 58-year-old woman with a chronic cough for over 20years who had an obstructive airway pattern on spirometry. Diagnoses of asthma and COPD had been discussed. After 7years of follow-up, the DIPNECH hypothesis was evoked on the scanning aspect of mosaic attenuation, expiratory trapping and micronodules, which was subsequently confirmed by surgical pulmonary biopsy. CONCLUSION: It is necessary to consider the possibility of this rare disease in order to avoid inappropriate treatments and in the hope that future therapeutic advances (somatostatin analogs, mTOR inhibitors) improve patients' experience and the progression of respiratory function.

Outbreak of measles and rubella in refugee transit camps.

In 2004, concurrent measles and rubella outbreaks occurred in four camps hosting 2767 Liberian refugees in Côte d'Ivoire. Sixty rash and fever cases were identified. From 19 January to 23 February 2004 (weeks 8-13), measles IgM testing showed that 61.1% were positive. The highest incidence rate (18.5%) of measles was observed in children aged <9 months. Ninety-three percent of children aged between 6 months and 15 years received a measles vaccine during week 13, but the rash and fever cases continued to occur. This prompted a systematic test for both measles and rubella IgM antibodies. Rubella IgM testing revealed 74.0% positive cases between 14 February and 25 April (weeks 11-21). The highest incidence rate (3.88%) of rubella was found in children aged between 5 and 15 years. Supplemental immunization with a measles-mumps-rubella (MMR) vaccine was conducted during week 20. This study illustrates the importance of testing for both measles and rubella in outbreaks of rash and fever in refugee settings.

[Value of hand disinfection by rubbing with alcohol prior to surgery in a tropical setting]. / Intérêt de la désinfection chirurgicale des mains par friction alcoolique en milieu tropical.

OBJECTIVE: The purpose of this study was to assess the value of hand disinfection by rubbing with alcohol in terms of prevention of surgical site infection (SSI) and cost in a tropical setting. MATERIAL AND METHOD: This prospective cohort study carried out in the Gynecology Obstetrics Department of the Yopougon University Teaching Hospital from May to September 2005 was designed to compare two different methods of hand disinfection, i.e., traditional 3-step hand scrubbing using an antiseptic preparation versus handwashing without an antiseptic preparation followed by two applications of an aqueous alcohol solution. RESULTS: The study population included 318 patients who underwent surgery during the study period. The SSI rate was 13.2% in patients operated on after traditional hand scrubbing and 11.5% after handwashing followed by rubbing with alcohol (not significantly different). Hand disinfection by rubbing with alcohol did not increase the risk of SSI and was considered as easier than traditional hand scrubbing by 90% of users. Skin tolerance was deemed good by 52% of users. Most users (69%) wished both hand disinfection methods to be available. Hand disinfection by rubbing with alcohol was much more cost-effective than traditional hand scrubbing both with regard to initial investment and to consumable costs (50% lower). CONCLUSION: This study shows that hand disinfection by rubbing with an alcoholic solution is not only as effective as traditional hand scrubbing for prevention of SSI but also more cost-effective. These findings indicate that rubbing with alcohol is a suitable alternative to traditional scrubbing for hand disinfection prior to surgery in our tropical setting.

In vitro and in vivo characteristics of a thermogelling and bioadhesive delivery system intended for rectal administration of quinine in children.

The aim of this work was to improve the rectal bioavailability of quinine hydrochloride by designing thermosensitive and mucoadhesive gels intended for rectal delivery. The rheological and mucoadhesive properties of poloxamer 407 solutions have been modulated by addition of hydroxypropylmethycellulose (HPMC) and propanediol-1,2. In vitro release and rectal absorption of quinine have been highlighted by a dialysis dissolution testing method and by the determination of bioavailability of the different formulations in rabbits. Increasing the proportions of HPMC and poloxamer in the formulations resulted in a prolonged release of quinine. Indeed, compared to the DT 50% of a rectal solution and a simple HPMC gel (27 and 65 min, respectively) the DT 50% of thermosensitive ternary systems was increased and ranged between 80 and 138 min, depending on the system composition. The release rate depended strongly on the elasticity of the gels after thermogelation. The absolute rectal bioavailability of quinine determined in rabbits was significantly improved with these thermosensitive and adhesive systems. It increased from 62% for the rectal solution to 98% for a ternary system 16/0.5/30 (poloxamer (16%)/HPMC (0.5%)/propanediol-1,2 (30%)). As a result of combined bioadhesion and prolonged release of quinine in vivo, higher average values of MRT and t(max) (9.1+/-0.2h and 30 min, respectively) were obtained compared to the rectal solution (6.9+/-0.9h and 15 min, respectively). Moreover, these formulations presented a very good rectal tolerance. Modulation by HPMC of the viscoelastic and mucoadhesive properties of poloxamer 407 thermogelling solutions allowed a prolonged release of quinine hydrochloride and an improvement of bioavailability in rabbit.

[Prevention of bleeding during laparotomic myomectomy in Sub-Saharan Africa: Contribution to the tourniquet on the uterine isthmus]. / Prévention de l'hémorragie per myomectomie en Afrique subsaharienne : apport du garrot sur l'isthme utérin.

OBJECTIVES: To appreciate the decrease of bleeding by myomectomy by the use of a tourniquet on the uterine isthmus. METHODS: We conducted a case-control retrospective study from March 2014 to February 2016 in the Gynecology and obstetrics Department of the university hospital of Yopougon (Abidjan, Ivory Coast). It interested 100 patients of which 50 had a myomectomy with the tourniquet on the uterine isthmus and 50 without the tourniquet. None of the patients received pre-operative preventive treatment. The criteria for comparison were the blood loss per operative and the pre-and post-operative hemoglobin levels. RESULTS: The average age of patients was 33 years. Nulliparous women were the group most affected (68% of our patients) with 32% infertile women in the group with the tourniquet and 18% in the group without the tourniquet. Patients without tourniquet presented more bleeding than patients with tourniquet (X2=13.61) with a higher proportion of anemic patients in the group without the tourniquet. The differences were significant. The tourniquet has made it possible to realize the resection of a larger number of myoma. The duration of hospital stay was 4 days on average in both groups and no complications were observed. CONCLUSIONS: The application of a tourniquet on the uterine isthmus during laparotomic myomectomy has a benefit in reducing intraoperative blood loss.

Description of strokes at the Bouaké University Hospital, Côte d'Ivoire.

INTRODUCTION: The incidence of stroke is rising in developing countries. In Côte d'Ivoire, it accounts for nearly 45 % of admissions to the neurology departments in Abidjan. In Bouaké, no study has dealt with this subject since peace returned. Our aim was to assess the epidemiological characteristics of stroke patients at Bouaké University Hospital. METHODOLOGY: This cross-sectional study took place from September 2013 to December 2015 and included all patients hospitalized for a stroke confirmed by brain imaging. RESULTS: The study included 164 cases: 60% ischemic strokes, and 40 % hemorrhagic. Patients' mean age was 62 years with a sex ratio of 0.66. Patients not in the labor force accounted for the largest portion (61.6 %). The interval between the stroke and admission to the neurology department ranged between 24 and 72 hours for 61 % of the patients. The main risk factor was hypertension (62.8 %). The average length of hospitalization was 8.44 days. Hospital mortality was 18.3 %. CONCLUSION: Stroke is responsible for high morbidity and mortality in the neurology department of Bouaké University Hospital.

Empirical and theoretical investigation into the potential impacts of insecticide resistance on the effectiveness of insecticide-treated bed nets.

In spite of widespread insecticide resistance in vector mosquitoes throughout Africa, there is limited evidence that long-lasting insecticidal bed nets (LLINs) are failing to protect against malaria. Here, we showed that LLIN contact in the course of host-seeking resulted in higher mortality of resistant Anopheles spp. mosquitoes than predicted from standard laboratory exposures with the same net. We also found that sublethal contact with an LLIN caused a reduction in blood feeding and subsequent host-seeking success in multiple lines of resistant mosquitoes from the laboratory and the field. Using a transmission model, we showed that when these LLIN-related lethal and sublethal effects were accrued over mosquito lifetimes, they greatly reduced the impact of resistance on malaria transmission potential under conditions of high net coverage. If coverage falls, the epidemiological impact is far more pronounced. Similarly, if the intensity of resistance intensifies, the loss of malaria control increases nonlinearly. Our findings help explain why insecticide resistance has not yet led to wide-scale failure of LLINs, but reinforce the call for alternative control tools and informed resistance management strategies.

Modulation of the rheological and mucoadhesive properties of thermosensitive poloxamer-based hydrogels intended for the rectal administration of quinine.

The aim of this work was to formulate and characterize thermosensitive gels based on poloxamer 407, a thermosensitive polymer, and hydroxypropylmethylcellulose (HPMC), a bioadhesive polymer, intended for the rectal delivery of quinine in children. In order to avoid the macroscopic phase separation between the two polymers it was necessary to add propanediol-1,2. After the formulation of stable ternary systems, their rheological properties were studied as a function of temperature. It was thus possible to obtained the gelation temperature of the systems as well as their elastic modulus, G', at 37 degrees C. It appeared that HPMC in the presence of propanediol-1,2 had a synergistic effect on the gelation of poloxamer 407. Tests on the rabbit rectal mucous membrane, founded on a technique of traction of the adhesive/adhered joint, made it possible to characterize the bioadhesive properties of the gels by measuring the work of adhesion, W, and the maximum detachment force, F(max). Over small concentration ranges of poloxamer and HPMC, very important variations of the viscoelastic and mucoadhesives properties were observed. It was shown that the viscoelastic and the bioadhesive properties were tightly correlated. Indeed, an empirical equivalence relation was established between the shear frequency and the rate of deformation in traction and allowed to describe all our samples by a master curve. This master curve would make it possible to predict the values of W at various rates of traction by the simple non-destructive measurement of the elastic modulus, G', at an equivalent shear frequency.