Malaria in Europe: A Historical Perspective

Survival and longevity of European rulers: geographical influences and exploring potential factors, including the Mediterranean diet - a historical analysis from 1354 to the twentieth century

Significant regional variability in lifespan in Europe is influenced by environmental factors and lifestyle behaviors, including diet. This study investigates the impact of geographical region on the lifespan of European rulers spanning from the fourteenth century to the present day. By analyzing historical records and literature, we aim to identify region-specific dietary patterns and lifestyle factors that may have contributed to longer lifespans among rulers. The hypothesis to be tested is that rulers from Southern European countries, where the traditional Mediterranean diet is consumed by the local people, may exhibit longer lifespans compared to rulers from other regions, due to the well-documented health benefits associated with this dietary pattern. We extracted comprehensive information for each ruler, encompassing their sex, birth and death dates, age, age of enthronement, duration of rulership, country, and cause of death (natural vs. non-natural). To determine their nationality, we coded rulers based on their hypothetical present-day residence (2023). Utilizing the EuroVoc Geographical classification, we categorized the countries into four regions: Northern, Western, Southern, Central and Eastern Europe. While Cox regression models did not find significant differences in survival rates among regions, further analysis stratified by time periods revealed intriguing trends. Contrary to our initial predictions, the Northern region displayed better survival rates compared to the Southern region between 1354 and 1499, whereas survival rates were similar across regions from 1500 to 1749. However, after 1750, all regions, except the Southern region, exhibited significantly improved survival rates, suggesting advancements in healthcare and lifestyle factors. These findings underscore the dynamic influence of both region and time period on health and longevity. Interestingly, despite the prevalence of the Mediterranean diet in the Southern region of Europe, rulers from this region did not demonstrate longer lifespans compared to their counterparts in other regions. This suggests that additional lifestyle factors may have played a more prominent role in their longevity. In conclusion, our study sheds light on the intricate relationship between region, time period, and lifespan among European rulers. Although the Mediterranean diet is often associated with health benefits, our findings indicate that it alone may not account for differences in ruler longevity across regions. Further research is warranted to explore the impact of other lifestyle factors on the health and lifespan of European rulers throughout history.

The prevalence of Pfk13 polymorphism in malaria patients treated with artemisinin-based therapy: a systematic review and meta-analysis

Artemisinin (ART) combination therapy is the main treatment for malaria. Pfk13 mutations (or K13 mutations, Kelch 13) are associated with ART resistance. This study aims to conduct a systematic review and meta-analysis of the prevalence of K13 mutations with ART resistance in malaria-endemic countries. An electronic search of studies in 2018 and a manual search in 2020 were performed to identify relevant studies. The risk of bias was assessed using the National Institutes of Health (NIH) quality assessment tool for observational cohort and cross-sectional studies. Data analysis was performed using R 4.1.0. Heterogeneity was estimated using the statistic I2 and Cochran Q test. A total of 170 studies were included in our review. Of these, 55 studies investigated the prevalence of K13 mutations in Southeast Asia. The meta-analysis showed that Southeast Asia had the highest prevalence of K13 mutations, whereas Africa, South America, Oceania, and other Asian countries outside Southeast Asia had a low prevalence of K13 mutations. The C580Y mutation was the most common in Southeast Asia with 35.5% (95%CI: 25.4-46.4%), whereas the dominant mutation in Africa was K189T (22.8%, 95%CI: 7.6-43.2%). This study revealed the emergence of ART resistance associated with K13 mutations in Southeast Asia. The diversity of each type of K13 mutation in other regions was also reported.

Coinfections and antimicrobial treatment in a cohort of falciparum malaria in a non-endemic country: a 10-year experience

INTRODUCTION

Falciparum malaria remains one of the deadliest infectious diseases worldwide. In Germany, it is mainly an imported infection among travellers. Rates of coinfection are often unknown, and a clinical rationale for the beneficial use of calculated antibiotic therapy in patients with malaria and suspected coinfection is lacking.

METHODS

We conducted an analysis of all in-patients treated with falciparum malaria at a German infectious diseases centre in vicinity to one of Europe's major airports for 2010-2019. Logistic regression and time-to-event analysis were used to evaluate predictors for bacterial coinfection, the use of antibacterial substances, as well as their influence on clinical course.

RESULTS

In total, 264 patients were included. Of those, 64% received an additional antibacterial therapy (n = 169). Twenty-nine patients (11.0%) were found to have suffered from a relevant bacterial coinfection, while only a small fraction had relevant bacteremia (n = 3, 1.4%). However, patients with severe malaria did not suffer from coinfections more frequently (p = 0.283). CRP levels were not a reliable predictor for a bacterial coinfection (OR 0.99, 95% CI 0.94-1.06, p = 0.850), while another clinical focus of infection was positively associated (OR 3.86, 95% CI 1.45-11.55, p  = 0.010).

CONCLUSION

Although bacterial coinfections were rare in patients with malaria at our centre, the risk does not seem negligible. These data point rather towards individual risk assessment in respective patients than to general empiric antibiotic use.

A History of Malaria and Conflict

It is supposed that in all armed conflicts until World War II more humans died of infectious diseases than of the actual violence. Especially malaria left a crucial imprint on wars throughout history. The disease aggravates wartime conditions, is thus responsible for significant morbidity and mortality in conflict zones, and is at the same time more commonly found in these areas. Malaria has halted many military campaigns in the past, with prominent examples ranging from antiquity through the medieval period and into the modern era. The parasitosis still continues to play an important role in the outcome of warfare and follow-up events today and is of special public health importance in areas of the Global South, where most of its endemicity and some of the most brutal conflicts of our time are located. Vice versa, wars and ensuing population movements increase malaria transmission and morbidity as well as impede control efforts. Awareness of this and the development of strategies to overcome both malaria and wars will massively improve the well-being of the population affected.

The millennial dynamics of malaria in the mediterranean basin: documenting Plasmodium spp. on the medieval island of Corsica

Introduction

The lack of well-preserved material upon which to base the paleo-microbiological detection of Plasmodium parasites has prevented extensive documentation of past outbreaks of malaria in Europe. By trapping intact erythrocytes at the time of death, dental pulp has been shown to be a suitable tissue for documenting ancient intraerythrocytic pathogens such as Plasmodium parasites.

Methods

Total DNA and proteins extracted from 23 dental pulp specimens collected from individuals exhumed from the 9th to 13th century archaeological site in Mariana, Corsica, were analyzed using open-mind paleo-auto-immunohistochemistry and direct metagenomics, Plasmodium-targeting immunochromatography assays. All experiments incorporated appropriate negative controls.

Results

Paleo-auto-immunohistochemistry revealed the presence of parasites Plasmodium spp. in the dental pulp of nine teeth. A further immunochromatography assay identified the presence of at least one Plasmodium antigen in nine individuals. The nine teeth, for which the PfHRP-2 antigen specific of P. falciparum was detected, were also positive using paleo-autoimmunohistochemistry and metagenomics.

Conclusion

Dental pulp erythrocytes proved to be suitable for the direct paleomicrobiology documentation of malaria in nine individuals buried in medieval Corsica, in agreement with historical data. This provides additional information on the millennial dynamics of Plasmodium spp. in the Mediterranean basin.

Introduction of invasive mosquito species into Europe and prospects for arbovirus transmission and vector control in an era of globalization

BACKGROUND

Mosquito research in Europe has a long history, primarily focused on malaria vectors. In recent years, invasive mosquito species like the Asian tiger mosquito (Aedes albopictus) and the spread of arboviruses like dengue virus, chikungunya virus or bluetongue virus have led to an intensification of research and monitoring in Europe. The risk of further dissemination of exotic species and mosquito-borne pathogens is expected to increase with ongoing globalization, human mobility, transport geography, and climate warming. Researchers have conducted various studies to understand the ecology, biology, and effective control strategies of mosquitoes and associated pathogens.

MAIN BODY

Three invasive mosquito species are established in Europe: Asian tiger mosquito (Aedes albopictus), Japanese bush mosquito (Ae. japonicus), and Korean bush mosquito (Aedes koreicus). Ae. albopictus is the most invasive species and has been established in Europe since 1990. Over the past two decades, there has been an increasing number of outbreaks of infections by mosquito-borne viruses in particular chikungunya virus, dengue virus or Zika virus in Europe primary driven by Ae. albopictus. At the same time, climate change with rising temperatures results in increasing threat of invasive mosquito-borne viruses, in particular Usutu virus and West Nile virus transmitted by native Culex mosquito species. Effective mosquito control programs require a high level of community participation, going along with comprehensive information campaigns, to ensure source reduction and successful control. Control strategies for container breeding mosquitoes like Ae. albopictus or Culex species involve community participation, door-to-door control activities in private areas. Further measures can involve integration of sterile insect techniques, applying indigenous copepods, Wolbachia sp. bacteria, or genetically modified mosquitoes, which is very unlike to be practiced as standard method in the near future.

CONCLUSIONS

Climate change and globalization resulting in the increased establishment of invasive mosquitoes in particular of the Asian tiger mosquito Ae. albopictus in Europe within the last 30 years and increasing outbreaks of infections by mosquito-borne viruses warrants intensification of research and monitoring. Further, effective future mosquito control programs require increase in intense community and private participation, applying physical, chemical, biological, and genetical control activities.

Viral RNA in Mosquitoes (Diptera: Culicidae) Collected between 2019 and 2021 in Germany

Due to globalisation and climate change, mosquito-borne pathogens are emerging in new areas on all continents, including Europe, which has recently faced outbreaks of dengue, chikungunya and West Nile fever. The present study complements previous investigations to evaluate the circulation of mosquito-borne viruses in Germany, with the aim of identifying potential vector species and risk areas. Mosquitoes collected from 2019 to 2021 and identified to species or species group level were screened for viruses of the families Flaviviridae, Peribunyaviridae and the genus Alphavirus of the family Togaviridae. In total, 22,528 mosquitoes were examined, thus providing the most comprehensive study on West Nile virus (WNV) circulation so far in the German mosquito population. Usutu virus (USUV) RNA was detected in six samples, Sindbis virus (SINV) RNA in 21 samples and WNV RNA in 11 samples. Samples containing RNA of USUV and WNV consisted of mosquitoes collected in the East German federal states of Brandenburg, Saxony and Saxony-Anhalt, while samples with RNA of SINV originated from more widespread locations. Although minimum infection rates have remained relatively low, the intensity of virus circulation appears to be increasing compared to previous studies. Continuous mosquito screening contributes to the early detection of the introduction and spread of mosquito-borne pathogens.

Transition Metal Complexes as Antimalarial Agents: A Review

In antimalarial drug development research, overcoming drug resistance has been a major challenge for researchers. Nowadays, several drugs like chloroquine, mefloquine, sulfadoxine, and artemisinin are used to treat malaria. But increment in drug resistance has pushed researchers to find novel drugs to tackle drug resistance problems. The idea of using transition metal complexes with pharmacophores as ligands/ligand pendants to show enhanced antimalarial activity with a novel mechanism of action has gained significant attention recently. The advantages of metal complexes include tunable chemical/physical properties, redox activity, avoiding resistance factors, etc. Several recent reports have successfully demonstrated that the metal complexation of known organic antimalarial drugs can overcome drug resistance by showing enhanced activities than the parent drugs. This review has discussed the fruitful research works done in the past few years falling into this criterion. Based on transition metal series (3d, 4d, or 5d), the antimalarial metal complexes have been divided into three broad categories (3d, 4d, or 5d metal-based), and their activities have been compared with the similar control complexes as well as the parent drugs. Furthermore, we have also commented on the potential issues and their possible solution for translating these metal-based antimalarial complexes into the clinic.

Evolution of Plasmodium vivax and resistance patterns for infection based on Duffy genotype and phenotype

The Duffy protein, a transmembrane molecule, acts as a receptor for various chemokines and facilitates binding between reticulocytes and the Plasmodium Duffy antigen binding protein. Duffy expression is associated with the Duffy chemokine receptor antigen genotype on chromosome 1 and exhibits variation across different geographic regions. Traditionally, the Duffy negative genotype and phenotype have been described to confer a certain level of protection against infection and symptom development. However, recent data suggest a shift in this behavior, with significantly higher prevalence observed in individuals with Duffy negative genotype or phenotype. Given that malaria is an endemic vector-borne disease in regions of Asia, Africa, and Latin America, posing a substantial global burden of disease and prioritizing public and global health, identifying evolutionary changes in infection and resistance patterns holds great importance for the design of strategies and reevaluation of conventional interventions. Hence, the aim of this review was to analyze the evolution of Plasmodium vivax and infection resistance patterns based on Duffy genotype and phenotype. The distribution of genotypes, phenotypes, and polymorphisms of P. vivax ligands and erythrocyte receptors varies geographically, notably resistance patterns of this microorganism in individuals with Duffy negative genotype and phenotype have significantly changed compared to studies conducted 30 years ago. The prevalence of vivax malaria in individuals with a Duffy negative status can reach up to 100%. Consequently, prioritizing research on this topic is essential for public health.

Microscopic Evidence of Malaria Infection in Visceral Tissue from Medici Family, Italy

Microscopy of mummified visceral tissue from a Medici family member in Italy identified a potential blood vessel containing erythrocytes. Giemsa staining, atomic force microscopy, and immunohistochemistry confirmed Plasmodium falciparum inside those erythrocytes. Our results indicate an ancient Mediterranean presence of P. falciparum, which remains responsible for most malaria deaths in Africa.

Use of rapid diagnostic tests for the detection of ancient malaria infections in dental pulp from the sixth century in Versailles, France

BACKGROUND

Paleomicrobiological data have clarified that Plasmodium spp. was circulating in the past in southern European populations, which are now devoid of malaria. The aim of this study was to evaluate the efficacy of immunodetection and, more particularly, rapid diagnostic tests (RDT), in order to further assess Plasmodium infections in ancient northern European populations.

METHODS

A commercially available RDT, PALUTOP^® + 4 OPTIMA, which is routinely used to detect malaria, was used to detect Plasmodium antigens from proteins recovered from ancient specimens extracted from 39 dental pulp samples. These samples were collected from 39 individuals who were buried in the sixth century, near the site of the current Palace of Versailles in France. Positive and negative controls were also used. Antigens detected were quantified using chemiluminescence imaging system analysis.

RESULTS

Plasmodium antigens were detected in 14/39 (35.9%) individuals, including Plasmodium vivax antigens in 11 individuals and Plasmodium falciparum antigens co-detected in two individuals, while Pan-Plasmodium antigens were detected in three individuals. Controls all yielded expected results.

CONCLUSIONS

The data reported here showed that RDTs are a suitable tool for detecting Plasmodium spp. antigens in ancient dental pulp samples, and demonstrated the existence of malaria in Versailles, France, in the sixth century. Plasmodium vivax, which is regarded as being responsible for an attenuated form of malaria and less deadly forms, was the most prevalent species. This illustrates, for the first time in ancient populations, co-infection with P. falciparum, bringing into question the climate-driven ecosystems prevailing at that time in the Versailles area.

Changes in the associations between malaria incidence and climatic factors across malaria endemic countries in Africa and Asia-Pacific region

Empirical evidence supporting the associations between malaria incidence and climatic factors has remained controversial, buffering the progress in the Global Malaria Program that aims to eliminate 90% of the world malaria burden by 2030. This study has aimed to evaluate the nature and extent at which these relations are maintained across all the malaria endemic countries of Africa and Asia-Pacific region. We have utilized the last two decades of malaria incidence, annual minimum temperature, and annual precipitation time series data (2000-2020) for the two most malaria-impacted regions. These data were fitted in the generalized linear model and the mixed effects model. The results showed that there exists a large heterogeneity in malaria incidence across the countries, and between the regions. Last two decadal tendencies showed significant reductions in the disease burden in almost all the countries in the Asia Pacific, with several exceptions or relatively slowed reductions in the Africa. We found significant changes in the positive linear associations between malaria incidence, annual minimum temperature, and annual precipitation across African countries. Many Asia-Pacific countries namely Bangladesh, Bhutan, Indonesia, South Korea, Nepal, Thailand, Vietnam showed negative effects in the associations with the annual precipitation. This study indicates that increasing temperature within the range of 12-30 °C can generate positive effects on malaria incidence, but the nature and extent of precipitation effects vary across countries and at a large regional scale.

Glycan masking in vaccine design: Targets, immunogens and applications

Glycan masking is a novel technique in reverse vaccinology in which sugar chains (glycans) are added on the surface of immunogen candidates to hide regions of low interest and thus focus the immune system on highly therapeutic epitopes. This shielding strategy is inspired by viruses such as influenza and HIV, which are able to escape the immune system by incorporating additional glycosylation and preventing the binding of therapeutic antibodies. Interestingly, the glycan masking technique is mainly used in vaccine design to fight the same viruses that naturally use glycans to evade the immune system. In this review we report the major successes obtained with the glycan masking technique in epitope-focused vaccine design. We focus on the choice of the target antigen, the strategy for immunogen design and the relevance of the carrier vector to induce a strong immune response. Moreover, we will elucidate the different applications that can be accomplished with glycan masking, such as shifting the immune response from hyper-variable epitopes to more conserved ones, focusing the response on known therapeutic epitopes, broadening the response to different viral strains/sub-types and altering the antigen immunogenicity to elicit higher or lower immune response, as desired.

Tentative indicators of malaria in archaeological skeletal samples, a pilot study testing different methods

OBJECTIVE

This study attempts to integrate multiple methods to investigate the presence of malaria in human skeletal samples from an archaeological context.

MATERIALS

33 well preserved human remains originating from a 17th-century archaeological site in southeastern Romania.

METHODS

The human bone samples were analyzed using rapid diagnostic tests for malaria antigens and PCR amplification of Plasmodium falciparum apical membrane antigen 1. A preliminary test was performed to identify and briefly characterize the presence of hemozoin using a combination of TEM imaging and diffraction.

RESULTS

The rapid diagnostic tests indicated that more than half of the examined samples were positive for Plasmodium antigens, but no traces of the parasites' genetic material were detected despite repeated attempts. The TEM images indicated that hemozoin might be a promising diagnostic marker of malaria in ancient bones.

CONCLUSIONS

The indisputable identification of malaria in the analyzed archaeological population was not possible as none of the applied methodological strategies turned out to be straightforward.

SIGNIFICANCE

This study reinforces the intricacy and limitations of unequivocally identifying malaria in past populations and sets the stage for future studies on such life-threatening infectious disease in a geographical space, which is currently underrepresented in the bioarchaeological literature.

LIMITATIONS

The low sample size and the lack of consistency across all assays hindered understanding the role of malaria in the studied population.

SUGGESTIONS FOR FURTHER RESEARCH

Further thorough multidisciplinary approaches on malaria detection in ancient settlements would be appropriate to inform our knowledge of its origins, frequency, and pathogen changes over centuries.

Evaluating the Performance of Deep Learning Frameworks for Malaria Parasite Detection Using Microscopic Images of Peripheral Blood Smears

Malaria is a significant health concern in many third-world countries, especially for pregnant women and young children. It accounted for about 229 million cases and 600,000 mortality globally in 2019. Hence, rapid and accurate detection is vital. This study is focused on achieving three goals. The first is to develop a deep learning framework capable of automating and accurately classifying malaria parasites using microscopic images of thin and thick peripheral blood smears. The second is to report which of the two peripheral blood smears is the most appropriate for use in accurately detecting malaria parasites in peripheral blood smears. Finally, we evaluate the performance of our proposed model with commonly used transfer learning models. We proposed a convolutional neural network capable of accurately predicting the presence of malaria parasites using microscopic images of thin and thick peripheral blood smears. Model evaluation was carried out using commonly used evaluation metrics, and the outcome proved satisfactory. The proposed model performed better when thick peripheral smears were used with accuracy, precision, and sensitivity of 96.97%, 97.00%, and 97.00%. Identifying the most appropriate peripheral blood smear is vital for improved accuracy, rapid smear preparation, and rapid diagnosis of patients, especially in regions where malaria is endemic.

Travel vaccines throughout history

Vaccinations are an important component of travel medicine. Beyond protection of travelers, vaccines are administered to prevent the importation of vaccine-preventable diseases at home and at destination. Proof of immunization to travel dates back to the first smallpox vaccine, developed by Edward Jenner in 1796. However, it took one century to generate the next vaccines against cholera, rabies, and typhoid fever. During the 20th century the armamentarium of vaccines used in travelers largely expanded with yellow fever, poliomyelitis, tetravalent meningococcal, and hepatitis A vaccines. The International Certificate of Inoculation and Vaccination was implemented in 1933. Currently there are vaccines administered to travelers following risk assessment, but also vaccines required according to the 2005 International Health Regulations and vaccines required at certain countries. Finally, within less than one year after the declaration of the coronavirus disease 2019 (COVID-19) pandemic, the first COVID-19 vaccines were launched and approved for emergency use to control the pandemic. Despite practical and ethical challenges, COVID-19 vaccine verifications have been widely used since spring 2021 in many activities, including international travel. In this article, we review the course of development of travel vaccines focusing on those for which a proof of vaccination has been or is required.