Challenges for the diagnosis and treatment of malaria in low transmission settings in San Lorenzo, Esmeraldas, Ecuador

Effects of drug pressure and human migration on antimalarial resistance in circulating Plasmodium falciparum malaria parasites in Ecuador

Antimalarial resistance in Plasmodium falciparum is a public health problem in the fight against malaria in Ecuador. Characterizing the molecular epidemiology of drug resistance genes helps to understand the emergence and spread of resistant parasites. In this study, the effects of drug pressure and human migration on antimalarial resistance in P. falciparum were evaluated. Sixty-seven samples from northwestern Ecuador from the 2019-2021 period were analyzed. SNPs in Pfcrt , Pfdhps , Pfdhfr , Pfmdr-1 , Pfk13 and Pfaat1 were identified by Sanger sequencing and whole-genome sequencing. A comparison of the frequencies of the haplotypes was made with data from the 2013-2015 period. Also, nucleotide and haplotype diversity were calculated. The frequencies of the mutant haplotypes, CVM ET in Pfcrt and C I C N I in Pfdhfr , increased. NED F S D F Y in Pfmdr-1 was detected for the first time. While the wild-type haplotypes, SAKAA in Pfdhps and MYRIC in Pfk13 , remained dominant. Interestingly, the A16 V mutation in Pfdhfr that gives resistance to proguanil is reported in Ecuador. In conclusion, parasites resistant to chloroquine ( Pfcrt ) and pyrimethamine ( Pfdhfr ) increased in recent years, while parasites sensitive to sulfadoxine ( Pfdhps ) and artemisinin ( Pfk13 ) prevail in Ecuador. Therefore, the current treatment is still useful against P. falciparum . The frequent human migration between Ecuador and Colombia has likely contributed to the spread of resistant parasites. Keys words : Plasmodium falciparum , resistance, antimalarial, selective pressure, human migration.

Impact of climate and land use/land cover changes on malaria incidence in the Ecuadorian Amazon

Malaria transmission is influenced by climate and land use/land cover change (LULC). This study examines the impact of climate and LULC on malaria risk in the Ecuadorian Amazon. Weekly malaria surveillance data between 2008 and 2019 from Ecuador's Ministry of Public Health were combined with hydrometeorological and LULC data. Cross-correlation analyses identified time lags. Bayesian spatiotemporal models estimated annual LULC rates of change (ARC) by census area and assessed the effects on Plasmodium vivax and Plasmodium falciparum incidence. ARC for the five land cover classes (forest, agriculture, urban, shrub vegetation, water) ranged from -1 to 4% with agriculture increasing across areas. Forest and shrub vegetation ARC were significantly associated with both Plasmodium vivax and Plasmodium falciparum. Temperature and terrestrial water content showed consistent negative relationships with both species. Precipitation had varying effects on Plasmodium vivax (null) and Plasmodium falciparum (increase) incidence. Shrubs and forest expansion, increased temperature, and terrestrial water content reduced malaria incidence, while increased precipitation had varying effects. Relationships between malaria, LULC, and climate are complex, influencing risk profiles. These findings aid decision-making and guide further research in the region.

Phenotypic resistance not associated with knockdown mutations (kdr) in Anopheles albimanus exposed to deltamethrin in southern coastal Ecuador

BACKGROUND

Decrease in malaria rates (e.g. incidence and cases) in Latin America maintains this region on track to achieve the goal of elimination. During the last 5 years, three countries have been certified as malaria free. However, the region fails to achieve the goal of 40% reduction on malaria rates and an increase of cases has been reported in some countries, including Ecuador. This scenario has been associated with multiple causes, such as decrease of funding to continue anti-malarial programmes and the development of insecticide resistance of the main malaria vectors. In Ecuador, official reports indicated phenotypic resistance in Aedes aegypti and Anopheles albimanus to deltamethrin and malathion, particularly in the coastal areas of Ecuador, however, information about the mechanisms of resistance have not been yet elucidated. This study aims to evaluate phenotypic response to deltamethrin and its relationship with kdr mutations in An. albimanus from two localities with different agricultural activities in southern coastal Ecuador.

METHODS

The CDC bottle assay was carried out to evaluate the phenotypic status of the mosquito's population. Sequencing the voltage gated sodium channel gene (VGSC) sought knockdown mutations (kdr) in codons 1010, 1013 and 1014 associated with resistance.

RESULTS

Phenotypic resistance was found in Santa Rosa (63.3%) and suspected resistance in Huaquillas (82.1%); with females presenting a higher median of knockdown rate (83.7%) than males (45.6%). No statistical differences were found between the distributions of knockdown rate for the two localities (p = 0.6048) which indicates no influence of agricultural activity. Although phenotypic resistance was confirmed, genetic analysis demonstrate that this resistance was not related with the kdr mechanism of the VGSC gene because no mutations were found in codons 1010 and 1013, while in codon 1014, 90.6% showed the susceptible sequence (TTG) and 7.3% ambiguous nucleotides (TKK and TYG).

CONCLUSIONS

These results highlighted the importance of continuous monitoring of resistance in malaria vectors in Ecuador, particularly in areas that have reported outbreaks during the last years. It is also important to elucidate the mechanism involved in the development of the resistance to PYs to propose alternative insecticides or strategies for vector control in areas where resistance is present.

Diagnosis and management of malaria in the intensive care unit

Malaria is responsible for approximately three-quarters of a million deaths in humans globally each year. Most of the morbidity and mortality reported are from Sub-Saharan Africa and Asia, where the disease is endemic. In non-endemic areas, malaria is the most common cause of imported infection and is associated with significant mortality despite recent advancements and investments in elimination programs. Severe malaria often requires intensive care unit admission and can be complicated by cerebral malaria, respiratory distress, acute kidney injury, bleeding complications, and co-infection. Intensive care management includes prompt diagnosis and early initiation of effective antimalarial therapy, recognition of complications, and appropriate supportive care. However, the lack of diagnostic capacities due to limited advances in equipment, personnel, and infrastructure presents a challenge to the effective diagnosis and management of malaria. This article reviews the clinical classification, diagnosis, and management of malaria as relevant to critical care clinicians, highlighting the role of diagnostic capacity, treatment options, and supportive care.

Barriers to accessing malaria treatment amongst school-age children in rural Malawi

BACKGROUND

Over the last two decades, many countries have moved from malaria control toward malaria elimination. However, some sub-Saharan African countries, like Malawi, have recently seen a reversal in malaria control progress with reported increases in confirmed malaria cases. This may be the result of inadequate access to effective malaria control interventions by key population groups that perpetuate transmission. This study aimed to assess the barriers to accessing malaria treatment among school-aged children (SAC) in Malawi.

METHODS

A qualitative study was conducted between September and October 2020, where data were gathered in rural Malawi using free-listing interviews, key-informant interviews, semi-structured interviews and focus group discussions. Purposively sampled participants included SAC, parents of SAC, health workers and key stakeholders at community and district levels. Interviews were digitally recorded and transcribed verbatim. Data were organized using NVivo 12 software and analysed using the thematic method.

RESULTS

The study recruited 252 participants, with 156 being SAC, equally divided between boys and girls. Health system barriers to malaria treatment included long waiting hours and queues at clinics, frequent stock-outs of medical supplies, and travel time to the facility. Provider barriers included negative attitude and limited service hours. Individual and cultural barriers included fear of malaria tests and beliefs associating witchcraft as the best treatment for malaria. In addition, COVID-19-related barriers included the inability to follow preventive measures, a shift in focus from malaria to COVID-19, and fear of contracting COVID-19 and/or being tested for COVID-19 at the facility.

CONCLUSIONS

This study shows most of the barriers to accessing malaria treatment among SAC are similar to those experienced by other population groups. Furthermore, COVID-19 adversely affected SAC's access to treatment. Interventions that support SAC access to prompt diagnosis and treatment are urgently needed to improve the effective control of malaria.

Molecular epidemiology of continued Plasmodium falciparum disease transmission after an outbreak in Ecuador

To better understand the factors underlying the continued incidence of clinical episodes of falciparum malaria in E-2025 countries targeting elimination, we characterized the molecular epidemiology of Plasmodium falciparum disease transmission after a clonal outbreak in Ecuador. Here we study disease transmission by documenting the diversity and population structure of the major variant surface antigen of the blood stages of P. falciparum encoded by the var multigene family. We used a high-resolution genotyping method, “varcoding”, involving targeted amplicon sequencing to fingerprint the DBLα encoding region of var genes to describe both antigenic var diversity and var repertoire similarity or relatedness in parasite isolates from clinical cases. We identified nine genetic varcodes in 58 P. falciparum isolates causing clinical disease in 2013-2015. Network analyses revealed that four of the varcodes were highly related to the outbreak varcode, with identification of possible diversification of the outbreak parasites by recombination as seen in three of those varcodes. The majority of clinical cases in Ecuador were associated with parasites with highly related or recombinant varcodes to the outbreak clone and due to local transmission rather than recent importation of parasites from other endemic countries. Sharing of types in Ecuadorian varcodes to those sampled in South American varcodes reflects historical parasite importation of some varcodes, especially from Colombia and Peru. Our findings highlight the translational application of varcoding for outbreak surveillance in epidemic/unstable malaria transmission, such as in E-2025 countries, and point to the need for surveillance of local reservoirs of infection in Ecuador to achieve the malaria elimination goal by 2025.

Stratification at the health district level for targeting malaria control interventions in Mali

Malaria is the leading cause of morbidity and mortality in Mali. Between 2017 and 2020, the number of cases increased in the country, with 2,884,827 confirmed cases and 1454 reported deaths in 2020. We performed a malaria risk stratification at the health district level in Mali with a view to proposing targeted control interventions. Data on confirmed malaria cases were obtained from the District Health Information Software 2, data on malaria prevalence and mortality in children aged 6-59 months from the 2018 Demographic and Health Survey, entomological data from Malian research institutions working on malaria in the sentinel sites of the National Malaria Control Program (NMCP), and environmental data from the National Aeronautics and Space Administration. A stratification of malaria risk was performed. Targeted malaria control interventions were selected based on spatial heterogeneity of malaria incidence, malaria prevalence in children, vector resistance distribution, health facility usage, child mortality, and seasonality of transmission. These interventions were discussed with the NMCP and the different funding partners. In 2017-2019, median incidence across the 75 health districts was 129.34 cases per 1000 person-years (standard deviation = 86.48). Risk stratification identified 12 health districts in very low transmission areas, 19 in low transmission areas, 20 in moderate transmission areas, and 24 in high transmission areas. Low health facility usage and increased vector resistance were observed in high transmission areas. Eight intervention combinations were selected for implementation. Our work provides an updated risk stratification using advanced statistical methods to inform the targeting of malaria control interventions in Mali. This stratification can serve as a template for continuous malaria risk stratifications in Mali and other countries.

Prevalencia de malaria gestacional en Ecuador

Introducción.

La malaria gestacional, definida como la presencia de Plasmodium spp. en sangre periférica materna o el hallazgo del parásito en la placenta, es considerada un importante problema de salud pública en las regiones tropicales y subtropicales.

Objetivo.

Determinar la frecuencia de casos de malaria gestacional diagnosticados en Ecuador entre 2015 y 2018.

Materiales y métodos.

Se hizo un estudio descriptivo, retrospectivo y transversal.

Resultados.

Se determinaron 46 casos de malaria gestacional en el período evaluado, 25 por Plasmodium falciparum y 21 por Plasmodium vivax, siendo el 2018 el año con más casos. En cuanto a las variables de edad y trimestre de gestación, prevalecieron en el grupo de 20 a 29 años (46 %) y en el segundo trimestre (37 %). Solo se observó una diferencia significativa entre los casos por año y la especie parasitaria.

Conclusión.

La malaria gestacional en Ecuador ha aumentado en los últimos cinco años, por lo que es importante informar a las mujeres en estado de gravidez sobre las medidas preventivas para evitar el contagio con el parásito, dadas las graves consecuencias que conlleva para ellas y sus hijos.

Performance of passive case detection for malaria surveillance: results from nine countries in Mesoamerica and the Dominican Republic

Background

In malaria elimination settings, available metrics for malaria surveillance have been insufficient to measure the performance of passive case detection adequately. An indicator for malaria suspected cases with malaria test (MSCT) is proposed to measure the rate of testing on persons presenting to health facilities who satisfy the definition of a suspected malaria case. This metric does not rely on prior knowledge of fever prevalence, seasonality, or external denominators, and can be used to compare detection rates in suspected cases within and between countries, including across settings with different levels of transmission.

Methods

To compute the MSCT, an operational definition for suspected malaria cases was established, including clinical and epidemiological criteria. In general, suspected cases included: (1) persons with fever detected in areas with active malaria transmission; (2) persons with fever identified in areas with no active transmission and travel history to, or residence in areas with active transmission (either national or international); and (3) persons presenting with fever, chills and sweating from any area. Data was collected from 9 countries: Belize, Colombia (in areas with active transmission), Costa Rica, Dominican Republic, El Salvador, Guatemala, Honduras, Nicaragua, and Panama (September–March 2020). A sample of eligible medical records for 2018 was selected from a sample of health facilities in each country. An algorithm was constructed to assess if a malaria test was ordered or performed for cases that met the suspected case definition.

Results

A sample of 5873 suspected malaria cases was obtained from 239 health facilities. Except for Nicaragua and Colombia, malaria tests were requested in less than 10% of all cases. More cases were tested in areas with active transmission than areas without cases. Travel history was not systematically recorded in any country.

Conclusions

A statistically comparable, replicable, and standardized metric was proposed to measure suspected malaria cases with a test (microscopy or rapid diagnostic test) that enables assessing the performance of passive case detection. Cross-country findings have important implications for malaria and infectious disease surveillance, which should be promptly addressed as countries progress towards malaria elimination. Local and easy-to-implement tools could be implemented to assess and improve passive case detection.

Herbal medicine use among pregnant women attending antenatal clinics in Lusaka Province, Zambia: A cross-sectional, multicentre study

BACKGROUND AND PURPOSE: The study of herbal medicine (HM) use which is related to maternal health, a public health priority in many sub-Saharan African countries including Zambia, has been limited. Accordingly, we aimed to determine the prevalence and patterns of HM use during pregnancy in Lusaka Province, Zambia.

MATERIALS AND METHODS

A survey-based (interviewer-administered), cross-sectional, multicentre study was conducted in 446 adult pregnant women attending antenatal clinics in June/July 2019.

RESULTS

Overall, 57.8% of participants reported using HM during their current pregnancy, with a mean of 2.0 ± 1.5 remedies/woman. Logistic regression analysis showed that HM use was significantly associated with HM use in prior pregnancies (p < 0.001) and willingness to use HM in the future (p < 0.001). The most commonly used herbs were lemon for nausea/vomiting and common cold, soybean to boost energy, ginger for common cold and nausea/vomiting, and Aloe vera for skin care. The perceived safety of HM (37.6%) and its complementary action with conventional medicines (35.3%) were the main reasons for HM use.

CONCLUSION

HM use among pregnant women attending antenatal clinics in Lusaka Province, Zambia is common, and a wide range of herbs is used.

Malaria situation in a clear area of Iran: an approach for the better understanding of the health service providers' readiness and challenges for malaria elimination in clear areas

Background

Malaria mortality and morbidity have decreased in recent years. Malaria elimination (ME) and effective efforts to achieve ME is one of the most important priorities for health systems in countries in the elimination phase. In very low transmission areas, the ME programme is faced with serious challenges. This study aimed to assess the trend while getting a better understanding of Health Service Providers’ (HSPs) readiness and challenges for ME in a clear area of Iran.

Methods

This study was performed in two phases. At first, the malaria trend in East Azerbaijan Province, was surveyed from 2001 to 2018; afterward, it was compared with the national situation for a better understanding of the second phase of the study. Data were collected from the Ministry of Health’s protocol and the health centre of the province. In the second phase, malaria control programme experts, health system researchers, and health managers’ opinions were collected via in-depth interviews. They were asked regarding HSPs readiness and appropriate Malaria Case Management (MCM) in a clear area and possible challenges.

Results

A total of 135 and 154,560 cases were reported in the last 18 years in East Azerbaijan Province and Iran, respectively. The incidence rate decreased in East Azerbaijan Province from 0.4/10,000 in 2001 to zero in 2018. Furthermore, no indigenous transmission was reported for 14 years. Also, for the first time, there was no indigenous transmission in Iran in 2018. The main elicited themes of HSPs readiness through in-depth interviews were: appropriate MCM, holistic and role-playing studies for assessment of HSPs performance, system mobilization, improving identification and diagnosis of suspected cases in the first line. Similarly, the main possible challenges were found to be decreasing health system sensitivity, malaria re-introduction, and withdrawing febrile suspected cases from the surveillance chain.

Conclusion

Health systems in eliminating phase should be aware that the absence of malaria cases reported does not necessarily mean that malaria is eliminated; in order to obtain valid data and to determine whether it is eliminated, holistic and role-playing studies are required. Increasing system sensitivity and mobilization are deemed important to achieve ME.