Importation of chloroquine-resistant Plasmodium falciparum by Guatemalan peacekeepers returning from the Democratic Republic of the Congo

UN peacekeeper health and risk factors --- a systematic scoping review

BACKGROUND

Conflicts, natural disasters, and complex emergencies present substantial health challenges to United Nations (UN) peacekeepers deployed in mission areas. This scoping review aims at summarizing previous research on the health of UN peacekeepers and identifies issues for further investigation.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for Scoping Reviews, we systematically searched Web of Science, PubMed, EMBASE, Scopus and China National Knowledge Infrastructure (CNKI) for English and Chinese literature published from April 1997 to November 2023. A data charting form was developed by two reviewers to extract relevant themes and provided narrative descriptions.

RESULTS

We screened 1079 de-duplicated records and included 143 studies in this scoping review. There were 112 studies on the health status of UN peacekeepers, with more than half on mental health problems such as stress and anxiety. Many studies explored the health status of UN peacekeepers in African countries deployed from mainly U.S., Canada, U.K., China, Australia and Norway. There were 39 studies on the health risk factors of UN peacekeepers, including natural environmental, social environmental, psychological, behavioral lifestyle, biological factors and health service factors. There were 62 articles on the health protection of UN peacekeepers, mainly based on previous deployment experience, with a lack of theoretical guidance from global health perspectives. This scoping review found that health problems of UN peacekeepers are complicated, and whose impacts are cross-border. Social environmental factors were explored the most among health risk factors. Disease prevention measures, medical and health measures, and psychosocial measures were the main health protection for UN peacekeepers.

CONCLUSIONS

This scoping review highlighted that health problems of UN peacekeepers were typical global health issues with complicated and cross-border health risk factors. Therefore, comprehensive strategies could be taken from global health perspectives, including multi-phases (before-deployment, during-deployment, and post-deployment), multi-disciplines (public health, medicine, politics, health diplomacy, and others), and multi-levels (the UN, host countries, troop-contributing countries, the UN peacekeeping team, and UN peacekeepers).

Assessment of Plasmodium falciparum anti-malarial drug resistance markers in pfcrt and pfmdr1 genes in isolates from Honduras and Nicaragua, 2018-2021

Background

Central America and the island of Hispaniola have set out to eliminate malaria by 2030. However, since 2014 a notable upturn in the number of cases has been reported in the Mosquitia region shared by Nicaragua and Honduras. In addition, the proportion of Plasmodium falciparum malaria cases has increased significantly relative to vivax malaria. Chloroquine continues to be the first-line drug to treat uncomplicated malaria in the region. The objective of this study was to evaluate the emergence of chloroquine resistant strains of P. falciparum using a genetic approach. Plasmodium vivax populations are not analysed in this study.

Methods

205 blood samples from patients infected with P. falciparum between 2018 and 2021 were analysed. The pfcrt gene fragment encompassing codons 72–76 was analysed. Likewise, three fragments of the pfmdr1 gene were analysed in 51 samples by nested PCR and sequencing.

Results

All samples revealed the CVMNK wild phenotype for the pfcrt gene and the N86, Y184F, S1034C, N1042D, D1246 phenotype for the pfmdr1 gene.

Conclusions

The increase in falciparum malaria cases in Nicaragua and Honduras cannot be attributed to the emergence of chloroquine-resistant mutants. Other possibilities should be investigated further. This is the first study to report the genotype of pfmdr1 for five loci of interest in Central America.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-03977-8.

Nationwide Monitoring for Plasmodium falciparum Drug-Resistance Alleles to Chloroquine, Sulfadoxine, and Pyrimethamine, Haiti, 2016-2017

Haiti is striving for zero local malaria transmission by the year 2025. Chloroquine remains the first-line treatment, and sulfadoxine/pyrimethamine (SP) has been used for mass drug-administration pilot programs. In March 2016, nationwide molecular surveillance was initiated to assess molecular resistance signatures for chloroquine and SP. For 778 samples collected through December 2017, we used Sanger sequencing to investigate putative resistance markers to chloroquine (Pfcrt codons 72, 74, 75, and 76), sulfadoxine (Pfdhps codons 436, 437, 540, 581, 613), and pyrimethamine (Pfdhfr codons 50, 51, 59, 108, 164). No parasites harbored Pfcrt point mutations. Prevalence of the Pfdhfr S108N single mutation was 47%, and we found the triple mutant Pfdhfr haplotype (108N, 51I, and 59R) in a single isolate. We observed no Pfdhps variants except in 1 isolate (A437G mutation). These data confirm the lack of highly resistant chloroquine and SP alleles in Haiti and support the continued use of chloroquine and SP.

A seven-year surveillance of epidemiology of malaria reveals travel and gender are the key drivers of dispersion of drug resistant genotypes in Kenya

Malaria drug resistance is a global public health concern. Though parasite mutations have been associated with resistance, other factors could influence the resistance. A robust surveillance system is required to monitor and help contain the resistance. This study established the role of travel and gender in dispersion of chloroquine resistant genotypes in malaria epidemic zones in Kenya. A total of 1,776 individuals presenting with uncomplicated malaria at hospitals selected from four malaria transmission zones in Kenya between 2008 and 2014 were enrolled in a prospective surveillance study assessing the epidemiology of malaria drug resistance patterns. Demographic and clinical information per individual was obtained using a structured questionnaire. Further, 2 mL of blood was collected for malaria diagnosis, parasitemia quantification and molecular analysis. DNA extracted from dried blood spots collected from each of the individuals was genotyped for polymorphisms in Plasmodium falciparum chloroquine transporter gene (Pfcrt 76), Plasmodium falciparum multidrug resistant gene 1 (Pfmdr1 86 and Pfmdr1 184) regions that are putative drug resistance genes using both conventional polymerase chain reaction (PCR) and real-time PCR. The molecular and demographic data was analyzed using Stata version 13 (College Station, TX: StataCorp LP) while mapping of cases at the selected geographic zones was done in QGIS version 2.18. Chloroquine resistant (CQR) genotypes across gender revealed an association with chloroquine resistance by both univariate model (p = 0.027) and by multivariate model (p = 0.025), female as reference group in both models. Prior treatment with antimalarial drugs within the last 6 weeks before enrollment was associated with carriage of CQR genotype by multivariate model (p = 0.034). Further, a significant relationship was observed between travel and CQR carriage both by univariate model (p = 0.001) and multivariate model (p = 0.002). These findings suggest that gender and travel are significantly associated with chloroquine resistance. From a gender perspective, males are more likely to harbor resistant strains than females hence involved in strain dispersion. On the other hand, travel underscores the role of transport network in introducing spread of resistant genotypes, bringing in to focus the need to monitor gene flow and establish strategies to minimize the introduction of resistance strains by controlling malaria among frequent transporters.

Human mobility and factors associated with malaria importation in Lusaka district, Zambia: a descriptive cross sectional study

Background

Malaria is a major public health problem in Zambia with an estimated 4 million confirmed cases and 2389 deaths reported in 2015. Efforts to reduce the incidence of malaria are often undermined by a number of factors such as human mobility which may lead to introduction of imported infections. The aim of this study was to establish the burden of malaria attributed to human mobility in Lusaka district and identify factors associated with malaria importation among residents of Lusaka district.

Methods

A cross sectional study was conducted in five randomly selected health facilities in Lusaka district from November 2015 to February 2016. Data was collected from 260 patients who presented with malaria and whose status was confirmed by rapid diagnostic test or microscopy. Each confirmed malaria case was interviewed using a structured questionnaire to establish their demographic characteristics, travel history and preventive measures. Travel history was used as a proxy to classify cases as either imported or local. Residency was also used as a secondary proxy for importation to compare characteristics of residents vs non-residents in relation to malaria importation. Logistic regression was used to determine factors associated with malaria importation among residents of Lusaka district.

Results

Out of 260 cases, 94.2% were classified as imported cases based on participants’ travel history. There were 131 (50.4%) males and 129 (49.6%) females. Age distribution ranged from 0 to 68 years with a median age of 15 years (IQR 8–27). Imported cases came from all the ten provinces of Zambia with the Copperbelt Province being the highest contributor (41%). Of all imported cases, use of prophylaxis was found to be highly protective [AOR = 0.22 (95% CI 0.06–0.82); p-value = 0.024]. Other factors that significantly influence malaria transmission and importation by residents include duration of stay in a highly endemic region [AOR = 1.25 (95% CI 1.09–1.44); p-value = 0.001] and frequency of travel [AOR = 3.71 (95% CI 1.26–10.84); p-value = 0.017].

Conclusion

Human mobility has influenced malaria transmission in Lusaka district through a number of factors by importing infections. This leads to onward transmission and poses a challenge to malaria elimination and control. However, taking of prophylaxis is highly protective and must be highly recommended.

Falciparum malaria molecular drug resistance in the Democratic Republic of Congo: a systematic review

Background

Malaria cases were estimated to 207 million in 2013. One of the problems of malaria control is the emergence and spread of Plasmodium falciparum strains that become resistant to almost all drugs available. Monitoring drug resistance is essential for early detection and subsequent prevention of the spread of drug resistance by timely changes of treatment policy. This review was performed to gather all data available on P. falciparum molecular resistance in DR Congo, as baseline for future assessments.

Methods

The search for this review was undertaken using the electronic databases PubMed and Google Scholar using the terms “malaria”, “Congo”, “resistance”, “molecular”, “antimalarial”, “efficacy”. Articles were classified based on year of collecting, year of publication, sample size and characteristics, molecular markers analysed and polymorphisms detected.

Results

Thirteen articles were included and five genes have been analysed in these studies: pfcrt, pfdhps, pfdhfr, pfmdr1 and K13-propeller. The majority of studies included were not representative of the whole country.

Conclusion

This systematic review demonstrates the lack of molecular resistance studies in DRC. Only 13 studies were identified in almost 15 years. The MOH must implement a national surveillance system for monitoring malaria drug resistance and this surveillance should be conducted frequently and country-representative.

A literature review of medical aspects of post-cold war UN peacekeeping operations: trends, lessons learnt, courses of action and recommendations

OBJECTIVE

Post-Cold War United Nations Peace Keeping Operations (UN PKOs) have been increasingly involved in dangerous areas with ill-defined boundaries, harsh and remote geographies, simmering internecine armed conflict and disregard on the part of some local parties for peacekeepers' security and role. In the interest of 'force protection' and optimising operations, a key component of UN PKOs is healthcare and medical treatment. The expectation is that UN PKO medical support will conform to the general intent and structure of UN PKOs. To do so requires effective policies and planning informed by a review of medical aspects crucial to UN PKOs. The intent of this article is to report on a review of principal medical aspects practical to post-Cold War UN PKOs.

METHODS

This review was assembled through a comprehensive, grounded, systematic iterative inquiry of open-source articles.

RESULTS

This inquiry revealed that the principal medical aspects in post-Cold War UN missions were the following: (1) the changed nature of UN PKOs, (2) new challenges in terms of proximity and distance to medical care, (3) expanded need for preventive medicine and disease contagion prevention and (4) increased propensity for psychological morbidity and need for intervention.

CONCLUSIONS

Post Cold War, the dramatically changed nature of UN PKOs has resulted in new challenges mainly in terms of medical logistics, preventive medicine and psychiatry. The changed nature of post-Cold War UN PKOs altered the character of medical support most notably regarding (1) a need for emphasis on immediate response proximate to medical events and rapid transport over long distances and traversing barriers to higher levels of care, (2) proactive contagion and hazard identification and prevention and (3) interventions designed to reduce psychological morbidity. Recommendations are offered about possible courses of action in terms of addressing trends found in identified medical aspects of PKOs.

Screening and Treating UN Peacekeepers to Prevent the Introduction of Artemisinin-Resistant Malaria into Africa

Stan Houston and Adam Houston highlight how deployment of UN peacekeepers has the potential to introduce artemisinin-resistant malaria into Africa.

Fighting fire with fire: mass antimalarial drug administrations in an era of antimalarial resistance

The emergence and spread of antimalarial resistance has been a major liability for malaria control. The spread of chloroquine-resistant Plasmodium falciparum strains had catastrophic consequences for people in malaria-endemic regions, particularly in sub-Saharan Africa. The recent emergence of artemisinin-resistant P. falciparum strains is of highest concern. Current efforts to contain artemisinin resistance have yet to show success. In the absence of more promising plans, it has been suggested to eliminate falciparum malaria from foci of artemisinin resistance using a multipronged approach, including mass drug administrations. The use of mass drug administrations is controversial as it increases drug pressure. Based on current knowledge it is difficult to conceptualize how targeted malaria elimination could contribute to artemisinin resistance, provided a full treatment course is ensured.

Genetic Evidence of Importation of Drug-Resistant Plasmodium falciparum to Guatemala from the Democratic Republic of the Congo

Molecular markers and population genetics were effective tracking tools.

Imported malaria threatens control and elimination efforts in countries that have low rates of transmission. In 2010, an outbreak of Plasmodium falciparum malaria was reported among United Nations peacekeeping soldiers from Guatemala who had recently returned from the Democratic Republic of the Congo (DRC). Epidemiologic evidence suggested that the soldiers were infected in the DRC, but local transmission could not be ruled out in all cases. We used population genetic analyses of neutral microsatellites to determine the outbreak source. Genetic relatedness was compared among parasites found in samples from the soldiers and parasite populations collected in the DRC and Guatemala; parasites identified in the soldiers were more closely related to those from the DRC. A phylogenetic clustering analysis confirms this identification with >99.9% confidence. Thus, results support the hypothesis that the soldiers likely imported malaria from the DRC. This study demonstrates the utility of molecular genotyping in outbreak investigations.

First imported Plasmodium ovale malaria in Central America: case report of a Guatemalan soldier and a call to improve its accurate diagnosis

The Mesoamerican Ministers of Health have set 2020 as the target for malaria elimination to be achieved in the region. Imported malaria cases are a potential threat to countries attempting elimination or working to prevent resurgence. We report the first imported Plasmodium ovale infection with molecular confirmation in Central America, which occurred in a Guatemalan soldier that had been deployed in Africa. The obstacles for its diagnosis using the standard microscopy technique and the need to improve its detection are discussed.

Fighting the good fight: the role of militaries in malaria elimination in Southeast Asia

Despite significant progress in malaria control in the Greater Mekong Subregion (GMS), malaria is still endemic, with more than 30 million people infected annually. Important gaps remain in case management, service delivery, prevention, and vector control, particularly in hard-to-reach mobile populations. Rapidly evolving drug resistance has created a new urgency to move aggressively toward elimination. However, no clear and cost-effective strategy has been identified. Although GMS militaries are under-recognized as a malaria transmission reservoir, they are an important focal point for elimination activities, given their high mobility, frequent malaria exposure, and potential for asymptomatic carriage. At the same time, military organizational capacity and proximity to other mobile populations could facilitate elimination efforts if relevant political barriers could be overcome. Here, we review considerations for military involvement in regional malaria elimination efforts.