Species composition and distribution of the Anopheles gambiae complex circulating in Kinshasa.

Understanding the distribution of Anopheles species is essential for planning and implementing malaria control programmes. This study assessed the composition and distribution of cryptic species of the main malaria vector, the Anopheles gambiae complex, in different districts of Kinshasa. Anopheles were sampled using CDC light traps in the four Kinshasa districts between July 2021 and June 2022, and then morphologically identified. Equal proportions of Anopheles gambiae s.l. per site were subjected to polymerase chain reaction to identify the cryptic species of the Anopheles gambiae complex. Anopheles gambiae complex specimens were identified throughout Kinshasa. The average density significantly differed inside and outside households. Two species of this complex circulate in Kinshasa: Anopheles gambiae and Anopheles coluzzii. In all the study sites, Anopheles gambiae was the most widespread species. Our results provide an important basis for future studies on the ecology and dynamics of cryptic species of the Anopheles gambiae complex in Kinshasa.

Data from Entomological Collections of Aedes (Diptera: Culicidae) in a post-epidemic area of Chikungunya, City of Kinshasa, Democratic Republic of Congo.

Arbovirus epidemics (chikungunya, dengue, West Nile fever, yellow fever and zika) are a growing threat in African areas where Aedes (Stegomyia) aegypti (Linnaeus, 1762) and Aedes albopictus (Skuse, 1895) are present. The lack of comprehensive sampling of these two vectors limits our understanding of their propagation dynamics in areas at risk of arboviruses. Here, we collected 6,943 observations (both larval and human capture) of Ae. aegypti and Ae. albopictus between 2020 and 2022. The study was carried out in the Vallee de la Funa, a post-epidemic zone in the city of Kinshasa, Democratic Republic of Congo. Our results provide important information for future basic and advanced studies on the ecology and phenology of these vectors, as well as on vector dynamics after a post-epidemic period. The data from this study are published in the public domain as the Darwin Core Archive in the Global Biodiversity Information Facility.

Epidemiology of Plasmodium malariae and Plasmodium ovale spp. in Kinshasa Province, Democratic Republic of Congo.

Reports suggest non-falciparum species are an underappreciated cause of malaria in sub-Saharan Africa but their epidemiology is ill-defined, particularly in highly malaria-endemic regions. We estimated incidence and prevalence of PCR-confirmed non-falciparum and Plasmodium falciparum malaria infections within a longitudinal study conducted in Kinshasa, Democratic Republic of Congo (DRC) between 2015-2017. Children and adults were sampled at biannual household surveys and routine clinic visits. Among 9,089 samples from 1,565 participants, incidences of P. malariae, P. ovale spp., and P. falciparum infections by 1-year were 7.8% (95% CI: 6.4%-9.1%), 4.8% (95% CI: 3.7%-5.9%) and 57.5% (95% CI: 54.4%-60.5%), respectively. Non-falciparum prevalences were higher in school-age children, rural and peri-urban sites, and P. falciparum co-infections. P. falciparum remains the primary driver of malaria in the DRC, though non-falciparum species also pose an infection risk. As P. falciparum interventions gain traction in high-burden settings, continued surveillance and improved understanding of non-falciparum infections are warranted.

Epidemiology of Plasmodium malariae and Plasmodium ovale spp. in a highly malaria-endemic country: a longitudinal cohort study in Kinshasa Province, Democratic Republic of Congo.

Background: Increasing reports suggest that non-falciparum species are an underappreciated cause of malaria in sub-Saharan Africa, but their epidemiology is not well-defined. This is particularly true in regions of high P. falciparum endemicity such as the Democratic Republic of Congo (DRC), where 12% of the world's malaria cases and 13% of deaths occur. Methods and Findings: The cumulative incidence and prevalence of P. malariae and P. ovale spp. infection detected by real-time PCR were estimated among children and adults within a longitudinal study conducted in seven rural, peri-urban, and urban sites from 2015-2017 in Kinshasa Province, DRC. Participants were sampled at biannual household survey visits (asymptomatic) and during routine health facility visits (symptomatic). Participant-level characteristics associated with non-falciparum infections were estimated for single- and mixed-species infections. Among 9,089 samples collected from 1,565 participants over a 3-year period, the incidence of P. malariae and P. ovale spp. infection was 11% (95% CI: 9%-12%) and 7% (95% CI: 5%-8%) by one year, respectively, compared to a 67% (95% CI: 64%-70%) one-year cumulative incidence of P. falciparum infection. Incidence continued to rise in the second year of follow-up, reaching 26% and 15% in school-age children (5-14yo) for P. malariae and P. ovale spp., respectively. Prevalence of P. malariae, P. ovale spp., and P. falciparum infections during household visits were 3% (95% CI: 3%-4%), 1% (95% CI: 1%-2%), and 35% (95% CI: 33%-36%), respectively. Non-falciparum malaria was more prevalent in rural and peri-urban vs. urban sites, in school-age children, and among those with P. falciparum co-infection. A crude association was detected between P. malariae and any anemia in the symptomatic clinic population, although this association did not hold when stratified by anemia severity. No crude associations were detected between non-falciparum infection and fever prevalence. Conclusions: P. falciparum remains the primary driver of malaria morbidity and mortality in the DRC. However, non-falciparum species also pose an infection risk across sites of varying urbanicity and malaria endemicity within Kinshasa, DRC, particularly among children under 15 years of age. As P. falciparum interventions gain traction in high-burden settings like the DRC, continued surveillance and improved understanding of non-falciparum infections are warranted.

Common breastfeeding problems experienced by lactating mothers during the first six months in Kinshasa.

INTRODUCTION: Breastfeeding has numerous advantages for infant, mother and society. However, many mothers discontinue breastfeeding due to problems they encounter. This study aimed to identify problems commonly experienced by breastfeeding mothers during the first six months in Kinshasa. METHODS: A prospective cohort study was carried out in Kinshasa from October 2012 to July 2013. A total of 422 mother-infant couples were recruited shortly after being discharged from twelve maternity facilities in Kinshasa and followed-up for six months. Interviews were conducted at the mother's house during the first week after birth, and thereafter at monthly intervals for six months. Data included mother's sociodemographic characteristics, the breastfeeding problems she experienced and information on child's feeding. Incidences of breastfeeding problems encountered during different periods were calculated as well as their confidence intervals. RESULTS: Cracked or sore nipples, insufficient production of milk and breast engorgement were the most commonly experienced problems by lactating mothers. The problems occurred mainly during the first week (17.1%; CI95% 13.7-21.1) and the rest of the first month (16.2%; CI95% 12.8-20.3). CONCLUSIONS: The first month after birth presents the most risk for the occurrence of breastfeeding problems. Mothers should be supported as soon as possible after delivery, to improve their breastfeeding performance and to be informed on how to maintain breast milk supply.

The effect of a mass distribution of insecticide-treated nets on insecticide resistance and entomological inoculation rates of Anopheles gambiae s.l. in Bandundu City, Democratic Repub`lic of Congo.

INTRODUCTION: insecticide-treated nets (ITNs) remain the mainstay of malaria vector control in the Democratic Republic of Congo. However, insecticide resistance of malaria vectors threatens their effectiveness. Entomological inoculation rates and insecticide susceptibility in Anopheles gambiae s.l. were evaluated before and after mass distribution of ITNs in Bandundu City for possible occurrence of resistance. METHODS: a cross-sectional study was conducted from 15th July 2015 to 15th June 2016. Adult mosquitoes were collected using pyrethrum spray catches and human landing catches and identified to species level and tested for the presence of sporozoites. Bioassays were carried out before and after distribution of ITNs to assess the susceptibility of adult mosquitoes to insecticides. Synergist bioassays were also conducted and target site mutations assessed using Polymerase chain reaction (PCR). RESULTS: a total of 1754 female An. gambiae s.l. were collected before and after deployment of ITNs. Fewer mosquitoes were collected after the distribution of ITNs. However, there was no significant difference in sporozoite rates or the overall entomological inoculation rate before and after the distribution of ITNs. Test-mosquitoes were resistant to deltamethrin, permethrin, and Dichlorodiphenyltrichloroethane but susceptible to bendiocarb. Pre-exposure of mosquitoes to Piperonyl butoxide increased their mortality after exposure to permethrin and deltamethrin. The frequency of the Kinase insert domain receptor (kdr)-West gene increased from 92 to 99% before and after the distribution of nets, respectively. CONCLUSION: seasonal impacts could be a limiting factor in the analysis of these data; however, the lack of decrease in transmission after the distribution of new nets could be explained by the high-level of resistance to pyrethroid.

Individual, household and neighborhood risk factors for malaria in the Democratic Republic of the Congo support new approaches to programmatic intervention.

BACKGROUND: The Democratic Republic of the Congo (DRC) remains one of the countries most impacted by malaria despite decades of control efforts, including multiple mass insecticide treated net (ITN) distribution campaigns. The multi-scalar and complex nature of malaria necessitates an understanding of malaria risk factors over time and at multiple levels (e.g., individual, household, community). Surveillance of households in both rural and urban settings over time, coupled with detailed behavioral and geographic data, enables the detection of seasonal trends in malaria prevalence and malaria-associated behaviors as well as the assessment of how the local environments within and surrounding an individual's household impact malaria outcomes. METHODS: Participants from seven sites in Kinshasa Province, DRC were followed for over two years. Demographic, behavioral, and spatial information was gathered from enrolled households. Malaria was assessed using both rapid diagnostic tests (RDT) and polymerase chain reaction (PCR) and seasonal trends were assessed. Hierarchical regression modeling tested associations between behavioral and environmental factors and positive RDT and PCR outcomes at individual, household and neighborhood scales. RESULTS: Among 1591 enrolled participants, malaria prevalence did not consistently vary seasonally across the sites but did vary by age and ITN usage. Malaria was highest and ITN usage lowest in children ages 6-15 years across study visits and seasons. Having another member of the household test positive for malaria significantly increased the risk of an individual having malaria [RDT: OR = 4.158 (2.86-6.05); PCR: OR = 3.37 (2.41-4.71)], as did higher malaria prevalence in the 250 m neighborhood around the household [RDT: OR = 2.711 (1.42-5.17); PCR: OR = 4.056 (2.3-7.16)]. Presence of water within close proximity to the household was also associated with malaria outcomes. CONCLUSIONS: Taken together, these findings suggest that targeting non-traditional age groups, children >5 years old and teenagers, and deploying household- and neighborhood-focused interventions may be effective strategies for improving malaria outcomes in high-burden countries like the DRC.

Analysis of false-negative rapid diagnostic tests for symptomatic malaria in the Democratic Republic of the Congo.

The majority of Plasmodium falciparum malaria diagnoses in Africa are made using rapid diagnostic tests (RDTs) that detect histidine-rich protein 2. Increasing reports of false-negative RDT results due to parasites with deletions of the pfhrp2 and/or pfhrp3 genes (pfhrp2/3) raise concern about existing malaria diagnostic strategies. We previously identified pfhrp2-negative parasites among asymptomatic children in the Democratic Republic of the Congo (DRC), but their impact on diagnosis of symptomatic malaria is unknown. We performed a cross-sectional study of false-negative RDTs in symptomatic subjects in 2017. Parasites were characterized by microscopy; RDT; pfhrp2/3 genotyping and species-specific PCR assays; a bead-based immunoassay for Plasmodium antigens; and/or whole-genome sequencing. Among 3627 symptomatic subjects, 427 (11.8%) had RDT-/microscopy + results. Parasites from eight (0.2%) samples were initially classified as putative pfhrp2/3 deletions by PCR, but antigen testing and whole-genome sequencing confirmed the presence of intact genes. 56.8% of subjects had PCR-confirmed malaria. Non-falciparum co-infection with P. falciparum was common (13.2%). Agreement between PCR and HRP2-based RDTs was satisfactory (Cohen's kappa = 0.66) and superior to microscopy (0.33). Symptomatic malaria due to pfhrp2/3-deleted P. falciparum was not observed. Ongoing HRP2-based RDT use is appropriate for the detection of falciparum malaria in the DRC.

Dysmorphism and major anomalies are a main predictor of survival in newborns admitted to the neonatal intensive care unit in the Democratic Republic of Congo.

In Central-Africa, neonatal infections, asphyxia and prematurity are main reasons for admission to the neonatal intensive care unit and major determinants of newborn survival. Also, the outcome of newborns with congenital anomalies is expected to be poor, due to a lack of state-of-the art care. We conducted a study of 102 newborns recruited in the Neonatal Intensive Care Unit (NICU) at the University Hospitals of Kinshasa, DR Congo, to assess the impact of congenital anomalies. The presence of a major anomaly was associated with a hazard ratio of death of 13.2 (95%CI: 3.7-46.7, p < .001). In addition, the presence of three or more minor anomalies was associated with a 4.5-fold increased risk of death (95%CI: 1.1-18.6, p = .04). We conclude that like major anomalies, the presence of three or more minor anomalies should also be given particular attention and that the evaluation of dysmorphism should be promoted in NICU.

Morphological characterization of newborns in Kinshasa, DR Congo: Common variants, minor, and major anomalies.

The evaluation of minor physical variation is crucial in a dysmorphological examination. Currently, data on the spectrum and incidence of minor physical variants in Central African newborns is lacking. We therefore conducted a cross-sectional descriptive study of 722 newborns recruited within the first 24 hr of life, in two large maternities in Kinshasa, DR Congo. Minor anomalies were defined according to the series of articles in AJMG Part A and coded as human phenotype ontology terms. A total of 97 different morphological variants were recorded of which 13 were common. About 34.8% of the newborn carried one minor anomaly, 11.6% had two, and 4.3% had three minor anomalies. No gender differences were observed, but the incidence of specific anomalies appeared to vary with the geographical origin of parents within the DR Congo. The results of this study will aid clinicians to interpret morphological variation in Central African newborns.