Seasonal malaria chemoprevention in a context of high presumed sulfadoxine-pyrimethamine resistance: malaria morbidity and molecular drug resistance profiles in South Sudan

BACKGROUND

Seasonal malaria chemoprevention (SMC) using sulfadoxine-pyrimethamine plus amodiaquine (SP-AQ), is a community-based malaria preventive strategy commonly used in the Sahel region of sub-Saharan Africa. However, to date it has not been implemented in East Africa due to high SP resistance levels. This paper is a report on the implementation of SMC outside of the Sahel in an environment with a high level of presumed SP-resistance: five cycles of SMC using SPAQ were administered to children 3-59 months during a period of high malaria transmission (July-December 2019) in 21 villages in South Sudan.

METHODS

A population-based SMC coverage survey was combined with a longitudinal time series analysis of health facility and community health data measured after each SMC cycle. SMC campaign effectiveness was assessed by Poisson model. SPAQ molecular resistance markers were additionally analysed from dried blood spots from malaria confirmed patients.

RESULTS

Incidence of uncomplicated malaria was reduced from 6.6 per 100 to an average of 3.2 per 100 after SMC administration (mean reduction: 53%) and incidence of severe malaria showed a reduction from 21 per 10,000 before SMC campaign to a mean of 3.3 per 10,000 after each cycle (mean reduction: 84%) in the target group when compared to before the SMC campaign. The most prevalent molecular haplotype associated with SP resistance was the IRNGE haplotype (quintuple mutant, with 51I/59R/108N mutation in pfdhfr + 437G/540E in pfdhps). In contrast, there was a low frequency of AQ resistance markers and haplotypes resistant to both drugs combined (< 2%).

CONCLUSIONS

The SMC campaign was effective and could be used as an additional preventive tool in seasonal malaria settings outside of the Sahel, especially in areas where access to health care is unstable. Malaria case load reduction was observed despite the high level of resistance to SP.

Screening for K13-Propeller Mutations Associated with Artemisinin Resistance in Plasmodium falciparum in Yambio County (Western Equatoria State, South Sudan)

Artemisinin-combined treatments are the recommended first-line treatment of Plasmodium falciparum malaria, but they are being threatened by emerging artemisinin resistance. Mutations in pfk13 are the principal molecular marker for artemisinin resistance. This study characterizes the presence of mutations in pfk13 in P. falciparum in Western Equatoria State, South Sudan. We analyzed 468 samples from patients with symptomatic malaria and found 15 mutations (8 nonsynonymous and 7 synonymous). Each mutation appeared only once, and none were validated or candidate markers of artemisinin resistance. However, some mutations were in the same or following position of validated and candidate resistance markers, suggesting instability of the gene that could lead to resistance. The R561L nonsynonymous mutation was found in the same position as the R561H validated mutation. Moreover, the A578S mutation, which is widespread in Africa, was also reported in this study. We found a high diversity of other pfk13 mutations in low frequency. Therefore, routine molecular surveillance of resistance markers is highly recommended to promptly detect the emergence of resistance-related mutations and to limit their spread.

Plasmodium falciparum pfhrp2 and pfhrp3 Gene Deletions in Malaria-Hyperendemic Region, South Sudan

Pfhrp2 and pfhrp3 gene deletions threaten the use of Plasmodium falciparum malaria rapid diagnostic tests globally. In South Sudan, deletion frequencies were 15.6% for pfhrp2, 20.0% for pfhrp3, and 7.5% for double deletions. Deletions were approximately twice as prevalent in monoclonal infections than in polyclonal infections.

Deletion patterns, genetic variability and protein structure of pfhrp2 and pfhrp3: implications for malaria rapid diagnostic test in Amhara region, Ethiopia

Background

Although rapid diagnostic tests (RDTs) play a key role in malaria-control strategies, their efficacy has been threatened by deletion and genetic variability of the genes pfhrp2/3. This study aims to characterize the deletion, genetic patterns and diversity of these genes and their implication for malaria RDT effectiveness, as well as their genetic evolution in the Amhara region of Ethiopia.

Methods

The study included 354 isolates from symptomatic patients from the Amhara region of Ethiopia who tested positive by microscopy. Exon 1–2 and exon 2 of genes pfhrp2 and -3 were amplified, and exon 2 was sequenced to analyse the genetic diversity, phylogenetic relationship and epitope availability.

Results

The deletion frequency in exon 1–2 and exon 2 was 22 and 4.6% for pfhrp2, and 68 and 18% for pfhrp3, respectively. Double deletion frequency for pfhrp2 and pfhrp3 was 1.4%. High genetic diversity, lack of clustering by phylogenetic analysis and evidence of positive selection suggested a diversifying selection for both genes. The amino-acid sequences, classified into different haplotypes, varied widely in terms of frequency of repeats, with novel amino-acid changes. Aminoacidic repetition type 2 and type 7 were the most frequent in all the sequences. The most frequent epitopes among protein sequences were those recognized by MAbs 3A4 and C1-13.

Conclusion

Deletions and high amino acidic variation in pfhrp2 and pfhrp3 suggest their possible impact on RDT use in the Amhara region, and the high genetic diversity of these genes could be associated with a diversifying selection in Ethiopia. Surveillance of these genes is, therefore, essential to ensure the effectiveness of public health interventions in this region.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04306-3.

Accessibility and availability of alcohol outlets around schools: An ecological study in the city of Madrid, Spain, according to socioeconomic area-level

Neighborhood accessibility and availability of alcohol products has been associated with increased alcohol consumption and harms among adolescents. This availability has been shown to be higher in neighborhoods with lower socio-economic status (SES). The aim of this study was to examine inequalities in alcohol outlet density and proximity around schools by area-level SES in Madrid, Spain. Data on schools, SES, alcohol outlets and population density at census tract level were obtained through public databases from the local government of Madrid. We examined (1) density as the number of alcohol outlets around schools within 3 buffers (i.e. 200 m, 400 m and 800 m) and (2) proximity as the distance from schools to their nearest alcohol outlet. We performed multilevel analyses to examine the associations between alcohol outlet density and proximity and SES, adjusted by population density. Secondary schools (n = 576) located in less deprived areas had lower densities of alcohol outlets at walking distances of 200 and 400 m (50% and 37% lower, respectively p < 0.05). No significant differences were found for the proximity measures. The socioeconomic level of the area in which adolescents go to school is a determinant of their exposure to alcohol, where those who study in high SES areas have lower exposure to alcohol outlets. This study highlights the need to prioritize equity in the design and implementation of policies to limit alcohol accessibility among adolescents, including establishing minimum distances between schools and alcohol outlets or limiting the number of outlets per inhabitant in neighborhoods.

Changes in perceptions of the alcohol environment among participants in a Photovoice project conducted in two districts with different socio-economic status

Perceptions of the alcohol environment may influence alcohol consumption patterns. The purpose of this study was to describe changes in perceptions of the urban alcohol environment as experienced by residents of two districts with different socio-economic status after taking part in a Photovoice study. The study was conducted in Madrid, Spain, in a district with a high socio-economic status (HSES) and another district with a low socio-economic status (LSES). A Photovoice project was conducted with 26 participants divided into four groups based on sex and district. Groups met over five sessions in which they discussed photographs taken by the participants themselves on the subject of alcohol in their neighbourhood. A qualitative, descriptive and thematic analysis of participants' discourses was performed to explore changes in their perceptions of the alcohol environment over the project sessions. Changes in perceptions of the alcohol environment were observed in all groups over the project. The process of change varied by districts' socio-economic characteristics and gender. Greater changes in perceptions of the alcohol environment were observed in HSES, especially among women, as the participants had a much more positive initial view of their alcohol environment. In LSES, participants showed a more critical perception of the alcohol environment from the beginning of the study, and this broadened and intensified over the course of the sessions. Changes in perceptions also varied by thematic categories, including some categories that were discussed from the start (e.g. socialising and alcohol consumption) and categories that only emerged in later sessions (e.g. alcohol advertising). Involvement in a Photovoice project has favoured a shift in the participant's perceptions of their alcohol environment towards more critical positions, widening their scope of perceived elements and raising their awareness of specific problems, such as alcohol advertising and social role of alcohol consumption in relation to alcohol exposure.

Impact of Plasmodium falciparum pfhrp2 and pfhrp3 gene deletions on malaria control worldwide: a systematic review and meta-analysis

Background

Deletion of pfhrp2 and/or pfhrp3 genes cause false negatives in malaria rapid diagnostic test (RDT) and threating malaria control strategies. This systematic review aims to assess the main methodological aspects in the study of pfhrp2 and pfhrp3 gene deletions and its global epidemiological status, with special focus on their distribution in Africa; and its possible impact in RDT.

Methods

The systematic review was conducted by examining the principal issues of study design and methodological workflow of studies addressing pfhrp2 deletion. Meta-analysis was applied to represent reported prevalences of pfhrp2 and pfhrp3 single and double deletion in the World Health Organization (WHO) region. Pooled-prevalence of deletions was calculated using DerSimonnian-Laird random effect model. Then, in-deep analysis focused on Africa was performed to assess possible variables related with these deletions. Finally, the impact of these deletions in RDT results was analysed combining reported information about RDT sensitivity and deletion prevalences.

Results

49 articles were included for the systematic review and 37 for the meta-analysis, 13 of them placed in Africa. Study design differs significantly, especially in terms of population sample and information reported, resulting in high heterogeneity between studies that difficulties comparisons and merged conclusions. Reported prevalences vary widely in all the WHO regions, significantly higher deletion were reported in South-Central America, following by Africa and Asia. Pfhrp3 deletion is more prevalent (43% in South-Central America; 3% in Africa; and 1% in Asia) than pfhrp2 deletion (18% in South-Central America; 4% in Africa; and 3% in Asia) worldwide. In Africa, there were not found differences in deletion prevalence by geographical or population origin of samples. The prevalence of deletion among false negatives ranged from 0 to 100% in Africa, but in Asia and South-Central America was only up to 90% and 48%, respectively, showing substantial relation between deletions and false negatives.

Conclusion

The concerning prevalence of pfhrp2, pfhrp3 and pfhrp2/3 gene deletions, as its possible implications in malaria control, highlights the importance of regular and systematic surveillance of these deletions. This review has also outlined that a standardized methodology could play a key role to ensure comparability between studies to get global conclusions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-03812-0.

How patients with COVID-19 managed the disease at home during the first wave in Spain: a cross-sectional study

OBJECTIVE

Most patients with mild COVID-19 had to stay at home trying to implement an optimal quarantine. The aim of this study was to describe the COVID-19 cases during the first wave of the pandemic in Spain, how they managed the disease at home, focusing on differences by age, as well as differences in knowledge, attitudes and preventive practices, compared with the uninfected population.

DESIGN

An online survey was used to conduct a cross-sectional study of individuals who were 14 years or older living in Spain during the COVID-19 lockdown. The main variable was a COVID-19 case. Logistic regression models for COVID-19 cases were obtained using a backward stepwise procedure to assess the association between social variables, disease knowledge, attitudes, prevention practices and emotional impact.

RESULTS

3398 people completed the survey. Participants' mean age was 49.6 (SD=14.3). COVID-19 was significantly more prevalent among married people (5.3%) and those currently doing an on-site work (8.7%). Most of the COVID-19 cases stayed at home (84.0%) during the episode. There were significant age-based differences with regard to self-isolation conditions at home during the disease. COVID-19 cases showed better attitudes, practices and knowledge about disease symptoms and transmission than the uninfected population. COVID-19 cases also felt more depressed (adjusted OR: 3.46, 95% CI 1.45 to 8.26) and had better preventive behaviour than the uninfected population, such as always wearing a mask outside the home (adjusted OR 1.58, 95% CI 1.06 to 2.30).

CONCLUSION

COVID-19 cases found it difficult to comply with recommended home self-isolation conditions, with differences by age group. COVID-19 had an important impact on care dependency in non-hospitalised patients, who were mostly dependent on their families for care. It is necessary to reinforce social and health services and to be ready to meet the care needs of populations during the different waves or in future epidemics.

Residents perceptions of the alcohol environment: A participatory photovoice project in two districts with different socio-economic status in a large city

The purpose of this study was to present the alcohol environment as perceived by its residents in two districts of Madrid using the Photovoice participatory methodology. Secondly, we compared the results according to the socio-economic status of the districts. The study was conducted in the city of Madrid, Spain, in two districts with different socio-economic status. A total of 26 people participated, who took and discussed photographs about their alcohol environment. They grouped them into 33 final categories, such as the socialising role of alcohol or the alcohol advertising. Co-authors further grouped participants final categories into seven general areas. The participants in the Photovoice project have helped to deepen the understanding of the alcohol urban environment. These results may help to design more effective policies to prevent hazardous alcohol consumption.