Antibody acquisition models: a new tool for serological surveillance of malaria transmission intensity

Serology has become an increasingly important tool for the surveillance of a wide range of infectious diseases. It has been particularly useful to monitor malaria transmission in elimination settings where existing metrics such as parasite prevalence and incidence of clinical cases are less sensitive. Seroconversion rates, based on antibody prevalence to Plasmodium falciparum asexual blood-stage antigens, provide estimates of transmission intensity that correlate with entomological inoculation rates but lack precision in settings where seroprevalence is still high. Here we present a new and widely applicable method, based on cross-sectional data on individual antibody levels. We evaluate its use as a sero-surveillance tool in a Tanzanian setting with declining malaria prevalence. We find that the newly developed mathematical models produce more precise estimates of transmission patterns, are robust in high transmission settings and when sample sizes are small, and provide a powerful tool for serological evaluation of malaria transmission intensity

Topical fluorouracil after surgery for ocular surface squamous neoplasia in Kenya: a randomised, double-blind, placebo-controlled trial

BACKGROUND: Ocular surface squamous neoplasia (OSSN) is an aggressive eye tumour particularly affecting people with HIV in Africa. Primary treatment is surgical excision; however, tumour recurrence is common. We assessed the effect of fluorouracil 1% eye drops after surgery on recurrence. METHODS: We did this multicentre, randomised, placebo-controlled trial in four centres in Kenya. We enrolled patients with histologically proven OSSN aged at least 18 years. After standard surgical excision, participants were randomly allocated to receive either topical fluorouracil 1% or placebo four times a day for 4 weeks. Randomisation was stratified by surgeon, and participants and trial personnel were masked to assignment. Patients were followed up at 1 month, 3 months, 6 months, and 12 months. The primary outcome was clinical recurrence (supported by histological assessment where available) by 1 year, and analysed by intention to treat. The sample size was recalculated because events were more common than anticipated, and trial enrolment was stopped early. The trial was registered with Pan-African Clinical Trials Registry (PACTR201207000396219). FINDINGS: Between August, 2012, and July, 2014, we assigned 49 participants to fluorouracil and 49 to placebo. Four participants were lost to follow-up. Recurrences occurred in five (11%) of 47 patients in the fluorouracil group and 17 (36%) of 47 in the placebo group (odds ratio 0·21, 95% CI 0·07–0·63; p=0·01). Adjusting for passive smoking and antiretroviral therapy had little effect (odds ratio 0·23; 95% CI 0·07–0·75; p=0·02). Adverse effects occurred more commonly in the fluorouracil group, although they were transient and mild. Ocular discomfort occurred in 43 of 49 patients in the fluorouracil group versus 36 of 49 in the placebo group, epiphora occurred in 24 versus five, and eyelid skin inflammation occurred in seven versus none. INTERPRETATION: Topical fluorouracil after surgery substantially reduced recurrence of OSSN, was well-tolerated, and its use recommended

Commonly cited incentives in the community implementation of the emergency maternal and newborn care study in western Kenya

Background: Mortality of mothers and newborns is an important public health problem in low-income countries. In the rural setting, implementation of community based education and mobilization are strategies that have sought to reduce these mortalities. Frequently such approaches rely on volunteers within each community. Objective: To assess the perceptions of the community volunteers in rural Kenya as they implemented the EmONC program and to identify the incentives that could result in their sustained engagement in the project. Method: A community-based cross sectional survey was administered to all volunteers involved in the study. Data were collected using a self-administered supervision tool from all the 881 volunteers. Results: 881 surveys were completed. 769 respondents requested some form of incentive; 200 (26%) were for monetary allowance, 149 (19.4%) were for a bicycle to be used for transportation, 119 (15.5%) were for uniforms for identification, 88 (11.4%) were for provision of training materials, 81(10.5%) were for training in Home based Life Saving Skills (HBLSS), 57(7.4%) were for provision of first AID kits, and 39(5%) were for provision of training more facilitators, 36(4.7%) were for provision of free medication. Conclusion: Monetary allowances, improved transportation and some sort of identification are the main incentives cited by the respondents in this context

Long-term effects of a preconception lifestyle intervention on cardiometabolic health of overweight and obese women

Background: The global prevalence of obesity in women keeps increasing. The preconception period may be a window of opportunity to improve lifestyle, reduce obesity and improve cardiometabolic health. This study assessed the effect of a preconception lifestyle intervention on long-term cardiometabolic health in two randomized controlled trials (RCTs).Methods: Participants of the LIFEstyle and RADIEL preconception lifestyle intervention studies with a baseline body mass index (BMI) ≥29 kg/m2 were eligible for this follow-up study. Both studies randomized between a lifestyle intervention targeting physical activity, diet and behaviour modification or usual care. We assessed cardiometabolic health 6 years after randomization.Results: In the LIFEstyle study (n = 111) and RADIEL study (n = 39), no statistically significant differences between the intervention and control groups were found for body composition, blood pressure, arterial stiffness, fasting glucose, homeostasis model assessment of insulin resistance, HbA1c, lipids and high sensitive C-reactive protein levels 6 years after randomization. Participants of the LIFEstyle study who successfully lost ≥5% bodyweight or reached a BMI &lt;29 kg/m2 during the intervention (n = 22, [44%]) had lower weight (-8.1 kg; 99% CI [-16.6 to -0.9]), BMI (-3.3 kg/m2; [-6.5 to -0.8]), waist circumference (-8.2 cm; [-15.3 to -1.3]), fasting glucose (-0.5 mmol/L; [-1.1 to -0.0]), HbA1c (-4.1 mmol/mol; [-9.1 to -0.8]), and higher HDL-C (0.3 mmol/L; [0.1-0.5]) compared with controls.Conclusion: We found no evidence of improved cardiometabolic health 6 years after a preconception lifestyle intervention among overweight and obese women in two RCTs. Women who successfully lost weight during the intervention had better cardiometabolic health 6 years later, emphasizing the potential of successful preconception lifestyle improvement.</p

The interaction between a sexually transferred steroid hormone and a female protein regulates oogenesis in the malaria mosquito anopheles gambiae

Molecular interactions between male and female factors during mating profoundly affect the reproductive behavior and physiology of female insects. In natural populations of the malaria mosquito Anopheles gambiae, blood-fed females direct nutritional resources towards oogenesis only when inseminated. Here we show that the mating-dependent pathway of egg development in these mosquitoes is regulated by the interaction between the steroid hormone 20-hydroxy-ecdysone (20E) transferred by males during copulation and a female Mating-Induced Stimulator of Oogenesis (MISO) protein. RNAi silencing of MISO abolishes the increase in oogenesis caused by mating in blood-fed females, causes a delay in oocyte development, and impairs the function of male-transferred 20E. Co-immunoprecipitation experiments show that MISO and 20E interact in the female reproductive tract. Moreover MISO expression after mating is induced by 20E via the Ecdysone Receptor, demonstrating a close cooperation between the two factors. Male-transferred 20E therefore acts as a mating signal that females translate into an increased investment in egg development via a MISO-dependent pathway. The identification of this male–female reproductive interaction offers novel opportunities for the control of mosquito populations that transmit malaria

Expansion of Inefficient HIV-Specific CD8 T Cells during Acute Infection

ABSTRACT Attrition within the CD4 + T cell compartment, high viremia, and a cytokine storm characterize the early days after HIV infection. When the first emerging HIV-specific CD8 + T cell responses gain control over viral replication it is incomplete, and clearance of HIV infection is not achieved even in the rare cases of individuals who spontaneously control viral replication to nearly immeasurably low levels. Thus, despite their partial ability to control viremia, HIV-specific CD8 + T cell responses are insufficient to clear HIV infection. Studying individuals in the first few days of acute HIV infection, we detected the emergence of a unique population of CD38 + CD27 − CD8 + T cells characterized by the low expression of the CD8 receptor (CD8 dim ). Interestingly, while high frequencies of HIV-specific CD8 + T cell responses occur within the CD38 + CD27 − CD8 dim T cell population, the minority populations of CD8 bright T cells are significantly more effective in inhibiting HIV replication. Furthermore, the frequency of CD8 dim T cells directly correlates with viral load and clinical predictors of more rapid disease progression. We found that a canonical burst of proliferative cytokines coincides with the emergence of CD8 dim T cells, and the size of this population inversely correlates with the acute loss of CD4 + T cells. These data indicate, for the first time, that early CD4 + T cell loss coincides with the expansion of a functionally impaired HIV-specific CD8 dim T cell population less efficient in controlling HIV viremia. IMPORTANCE A distinct population of activated CD8 + T cells appears during acute HIV infection with diminished capacity to inhibit HIV replication and is predictive of viral set point, offering the first immunologic evidence of CD8 + T cell dysfunction during acute infection

Ecogeographical distribution of wild, weedy and cultivated Sorghum bicolor (L.) Moench in Kenya: implications for conservation and crop-to-wild gene flow

The potential gene flow between a crop and its wild relatives is largely determined by the overlaps in their ecological and geographical distributions. Ecogeographical databases are therefore indispensable tools for the sustainable management of genetic resources. In order to expand our knowledge of Sorghum bicolor distribution in Kenya, we conducted in situ collections of wild, weedy and cultivated sorghum. Qualitative and quantitative morphological traits were measured for each sampled wild sorghum plant. Farmers’ knowledge relating to the management of sorghum varieties and autecology of wild sorghum was also obtained. Cluster analysis supports the existence of several wild sorghum morphotypes that might correspond to at least three of the five ecotypes recognized in Africa. Intermediate forms between wild and cultivated sorghum belonging to the S. bicolor ssp. drummondii are frequently found in predominantly sorghum growing areas. Crop-wild gene flow in sorghum is likely to occur in many agroecosystems of Kenya

The Major Yolk Protein Vitellogenin Interferes with the Anti-Plasmodium Response in the Malaria Mosquito Anopheles gambiae

Functional gene analysis in malaria mosquitoes reveals molecules underpinning the trade-off between efficient reproduction and the antiparasitic response