Dual infection with HIV and malaria fuels the spread of both diseases in sub-Saharan Africa

Individual virome analysis reveals the general co-infection of mammal-associated viruses with SARS-related coronaviruses in bats

Bats are the natural reservoir hosts for SARS-related coronavirus (SARSr-CoV) and other highly pathogenic microorganisms. Therefore, it is conceivable that an individual bat may harbor multiple microbes. However, there is limited knowledge on the overall co-circulation of microorganisms in bats. Here, we conducted a 16-year monitoring of bat viruses in south and central China and identified 238 SARSr-CoV positive samples across nine bat species from ten provinces or administrative districts. Among these, 76 individual samples were selected for further metagenomics analysis. We found a complex microenvironment characterized by the general co-circulation of microbes from two different sources: mammal-associated viruses or environment-associated microbes. The later includes commensal bacteria, enterobacteria-related phages, and insect or fungal viruses of food origin. Results showed that 25% (19/76) of the samples contained at least one another mammal-associated virus, notably alphacoronaviruses (13/76) such as AlphaCoV/YN2012, HKU2-related CoV and AlphaCoV/Rf-HuB2013, along with viruses from other families. Notably, we observed three viruses co-circulating within a single bat, comprising two coronavirus species and one picornavirus. Our analysis also revealed the potential presence of pathogenic bacteria or fungi in bats. Furthermore, we obtained 25 viral genomes from the 76 bat SARSr-CoV positive samples, some of which formed new evolutionary lineages. Collectively, our study reveals the complex microenvironment of bat microbiome, facilitating deeper investigations into their pathogenic potential and the likelihood of cross-species transmission.

Elevated Inflammation Associated with Markers of Neutrophil Function and Gastrointestinal Disruption in Pilot Study of Plasmodium fragile Co-Infection of ART-Treated SIVmac239+ Rhesus Macaques

Human immunodeficiency virus (HIV) and malaria, caused by infection with Plasmodium spp., are endemic in similar geographical locations. As a result, there is high potential for HIV/Plasmodium co-infection, which increases the pathology of both diseases. However, the immunological mechanisms underlying the exacerbated disease pathology observed in co-infected individuals are poorly understood. Moreover, there is limited data available on the impact of Plasmodium co-infection on antiretroviral (ART)-treated HIV infection. Here, we used the rhesus macaque (RM) model to conduct a pilot study to establish a model of Plasmodium fragile co-infection during ART-treated simian immunodeficiency virus (SIV) infection, and to begin to characterize the immunopathogenic effect of co-infection in the context of ART. We observed that P. fragile co-infection resulted in parasitemia and anemia, as well as persistently detectable viral loads (VLs) and decreased absolute CD4+ T-cell counts despite daily ART treatment. Notably, P. fragile co-infection was associated with increased levels of inflammatory cytokines, including monocyte chemoattractant protein 1 (MCP-1). P. fragile co-infection was also associated with increased levels of neutrophil elastase, a plasma marker of neutrophil extracellular trap (NET) formation, but significant decreases in markers of neutrophil degranulation, potentially indicating a shift in the neutrophil functionality during co-infection. Finally, we characterized the levels of plasma markers of gastrointestinal (GI) barrier permeability and microbial translocation and observed significant correlations between indicators of GI dysfunction, clinical markers of SIV and Plasmodium infection, and neutrophil frequency and function. Taken together, these pilot data verify the utility of using the RM model to examine ART-treated SIV/P. fragile co-infection, and indicate that neutrophil-driven inflammation and GI dysfunction may underlie heightened SIV/P. fragile co-infection pathogenesis.

Comparative analysis and evolution of civilian versus combatant mortality ratios in Israel-Gaza conflicts, 2008-2023

Background

There is a need for statistical methodologies that scrutinize civilian casualties in conflicts, evaluating the degree to which the conduct of war affects civilians and breaches the laws of war. Employing an epidemiological method, this study introduced, developed, and applied a novel approach for investigating mortality of civilians versus combatants in conflicts.

Methods

A deterministic mathematical model, structured by age and sex, was developed to describe the process of conflict-related deaths among both combatants and civilians. The model was calibrated using demographic and conflict-related data from different Israel-Gaza conflicts. To quantify the extent of the impact on civilians and determine whether they are the primary focus of a conflict, a statistical metric, the index of killing civilians, along with associated criteria, was devised.

Results

The model-estimated proportion of deaths in Gaza categorized as combatants was 62.1% (95% uncertainty interval (UI): 57.6-66.2%), 51.1% (95% UI: 47.1-54.9%), and 12.7% (95% UI: 9.7-15.4%) in the 2008-2009, 2014, and 2023 Israel-Gaza conflicts, respectively. The index of killing civilians was 0.61 (95% UI: 0.51-0.74), 0.96 (95% UI: 0.82-1.12), and 7.01 (95% UI: 5.50-9.29) in the 2008-2009, 2014, and 2023 conflicts, respectively. These index values indicate strong evidence for civilians being an object of war in the 2008-2009 and 2014 conflicts, but combatants were still identified as the primary focus of the conflict. In the 2023 conflict, there is robust evidence for civilians being an object of war, with civilians identified as the primary focus of the conflict.

Conclusion

Findings imply a progressive shift in Israel's rules of engagement over time, with a trend towards higher acceptance of casualties among civilians. The 2023 conflict stands apart from preceding Israel-Gaza conflicts, with civilians identified as the primary focus of the conflict.

Microfluidic System-Based Quantitative Analysis of Platelet Function through Speckle Size Measurement

Platelets play essential roles in the formation of blood clots by clumping with coagulation factors at the site of vascular injury to stop bleeding; therefore, a reduction in the platelet number or disorder in their function causes bleeding risk. In our research, we developed a method to assess platelet aggregation using an optical approach within a microfluidic chip's channel by evaluating the size of laser speckles. These speckles, associated with slowed blood flow in the microfluidic channel, had a baseline size of 28.54 ± 0.72 µm in whole blood. Removing platelets from the sample led to a notable decrease in speckle size to 27.04 ± 1.23 µm. Moreover, the addition of an ADP-containing agonist, which activates platelets, resulted in an increased speckle size of 32.89 ± 1.69 µm. This finding may provide a simple optical method via microfluidics that could be utilized to assess platelet functionality in diagnosing bleeding disorders and potentially in monitoring therapies that target platelets.

Understanding dynamics and overlapping epidemiologies of HIV, HSV-2, chlamydia, gonorrhea, and syphilis in sexual networks of men who have sex with men

Introduction

We aimed to investigate the overlapping epidemiologies of human immunodeficiency virus (HIV), herpes simplex virus type 2 (HSV-2), chlamydia, gonorrhea, and syphilis in sexual networks of men who have sex with men (MSM), and to explore to what extent the epidemiology of one sexually transmitted infection (STI) relates to or differs from that of another STI.

Methods

An individual-based Monte Carlo simulation model was employed to simulate the concurrent transmission of STIs within diverse sexual networks of MSM. The model simulated sexual partnering, birth, death, and STI transmission within each specific sexual network. The model parameters were chosen based on the current knowledge and understanding of the natural history, transmission, and epidemiology of each considered STI. Associations were measured using the Spearman's rank correlation coefficient (SRCC) and maximal information coefficient (MIC).

Results

A total of 500 sexual networks were simulated by varying the mean and variance of the number of partners for both short-term and all partnerships, degree correlation, and clustering coefficient. HSV-2 had the highest current infection prevalence across the simulations, followed by HIV, chlamydia, syphilis, and gonorrhea. Threshold and saturation effects emerged in the relationship between STIs across the simulated networks, and all STIs demonstrated moderate to strong associations. The strongest current infection prevalence association was between HIV and gonorrhea, with an SRCC of 0.84 (95% CI: 0.80-0.87) and an MIC of 0.81 (95% CI: 0.74-0.88). The weakest association was between HSV-2 and syphilis, with an SRCC of 0.54 (95% CI: 0.48-0.59) and an MIC of 0.57 (95% CI, 0.49-0.65). Gonorrhea exhibited the strongest associations with the other STIs while syphilis had the weakest associations. Across the simulated networks, proportions of the population with zero, one, two, three, four, and five concurrent STI infections were 48.6, 37.7, 11.1, 2.4, 0.3, and < 0.1%, respectively. For lifetime exposure to these infections, these proportions were 13.6, 21.0, 22.9, 24.3, 13.4, and 4.8%, respectively.

Conclusion

STI epidemiologies demonstrate substantial overlap and associations, alongside nuanced differences that shape a unique pattern for each STI. Gonorrhea exhibits an "intermediate STI epidemiology," reflected by the highest average correlation coefficient with other STIs.

Uncovering HIV and malaria interactions: the latest evidence and knowledge gaps

The geographical distribution of malaria and HIV infections widely overlap in sub-Saharan Africa, constituting a complex global health challenge. The interplay between both infections raises concerns about potential immunological, clinical, and therapeutic interactions. Both diseases have been reported to exacerbate the transmission of the other, including the possible vertical transmission of HIV in pregnant individuals with malaria. Co-infection also increases the risk of adverse outcomes such as severe malaria and death. In addition, interactions between antiretroviral and antimalarial drugs have been reported, potentially reducing the efficacy of these drugs. We review the current knowledge of the epidemiological, clinical, immunological, and therapeutic interactions of both infections. We focus on the latest available data and identify key knowledge gaps that should be addressed to guide policy makers in providing optimal HIV and malaria prevention, care, and treatment in vulnerable populations.

Age Structure Eliminates the Impact of Coinfection on Epidemic Dynamics in a Freshwater Zooplankton System

AbstractParasites often coinfect host populations and, by interacting within hosts, might change the trajectory of multiparasite epidemics. However, host-parasite interactions often change with host age, raising the possibility that within-host interactions between parasites might also change, influencing the spread of disease. We measured how heterospecific parasites interacted within zooplankton hosts and how host age changed these interactions. We then parameterized an epidemiological model to explore how age effects altered the impact of coinfection on epidemic dynamics. In our model, we found that in populations where epidemiologically relevant parameters did not change with age, the presence of a second parasite altered epidemic dynamics. In contrast, when parameters varied with host age (based on our empirical measures), there was no longer a difference in epidemic dynamics between singly infected and coinfected populations, indicating that variable age structure within a population eliminates the impact of coinfection on epidemic dynamics. Moreover, infection prevalence of both parasites was lower in populations where epidemiologically relevant parameters changed with age. Given that host population age structure changes over time and space, these results indicate that age effects are important for understanding epidemiological processes in coinfected systems and that studies focused on a single age group could yield inaccurate insights.

Investigating the outcomes of virus coinfection within and across host species

Interactions between coinfecting pathogens have the potential to alter the course of infection and can act as a source of phenotypic variation in susceptibility between hosts. This phenotypic variation may influence the evolution of host-pathogen interactions within host species and interfere with patterns in the outcomes of infection across host species. Here, we examine experimental coinfections of two Cripaviruses-Cricket Paralysis Virus (CrPV), and Drosophila C Virus (DCV)-across a panel of 25 Drosophila melanogaster inbred lines and 47 Drosophilidae host species. We find that interactions between these viruses alter viral loads across D. melanogaster genotypes, with a ~3 fold increase in the viral load of DCV and a ~2.5 fold decrease in CrPV in coinfection compared to single infection, but we find little evidence of a host genetic basis for these effects. Across host species, we find no evidence of systematic changes in susceptibility during coinfection, with no interaction between DCV and CrPV detected in the majority of host species. These results suggest that phenotypic variation in coinfection interactions within host species can occur independently of natural host genetic variation in susceptibility, and that patterns of susceptibility across host species to single infections can be robust to the added complexity of coinfection.

COVID-19, Mental Health, and Chronic Illnesses: A Syndemic Perspective

BACKGROUND

The COVID-19 pandemic is an epidemiological and psychological crisis; what it does to the body is quite well known by now, and more research is underway, but the syndemic impact of COVID-19 and mental health on underlying chronic illnesses among the general population is not completely understood.

METHODS

We carried out a literature review to identify the potential impact of COVID-19 and related mental health issues on underlying comorbidities that could affect the overall health of the population.

RESULTS

Many available studies have highlighted the impact of COVID-19 on mental health only, but how complex their interaction is in patients with comorbidities and COVID-19, the absolute risks, and how they connect with the interrelated risks in the general population, remain unknown. The COVID-19 pandemic can be recognized as a syndemic due to; synergistic interactions among different diseases and other health conditions, increasing overall illness burden, emergence, spread, and interactions between infectious zoonotic diseases leading to new infectious zoonotic diseases; this is together with social and health interactions leading to increased risks in vulnerable populations and exacerbating clustering of multiple diseases.

CONCLUSION

There is a need to develop evidence to support appropriate and effective interventions for the overall improvement of health and psychosocial wellbeing of at-risk populations during this pandemic. The syndemic framework is an important framework that can be used to investigate and examine the potential benefits and impact of codesigning COVID-19/non-communicable diseases (NCDs)/mental health programming services which can tackle these epidemics concurrently.

The enemy of my enemy is my friend: Immune-mediated facilitation contributes to fitness of co-infecting helminths

The conceptual understanding of immune-mediated interactions between parasites is rooted in the theory of community ecology. One of the limitations of this approach is that most of the theory and empirical evidence has focused on resource or immune-mediated competition between parasites and yet there is ample evidence of positive interactions that could be generated by immune-mediated facilitation. We developed an immuno-epidemiological model and applied it to long-term data of two gastrointestinal helminths in two rabbit populations to investigate, through model testing, how immune-mediated mechanisms of parasite regulation could explain the higher intensities of both helminths in rabbits with dual than single infections. The model framework was selected and calibrated on rabbit population A and then validated on the nearby rabbit population B to confirm the consistency of the findings and the generality of the mechanisms. Simulations suggested that the higher intensities in rabbits with dual infections could be explained by a weakened or low species-specific IgA response and an asymmetric IgA cross-reaction. Simulations also indicated that rabbits with dual infections shed more free-living stages that survived for longer in the environment, implying greater transmission than stages from hosts with single infections. Temperature and humidity selectively affected the free-living stages of the two helminths. These patterns were comparable in the two rabbit populations and support the hypothesis that immune-mediated facilitation can contribute to greater parasite fitness and local persistence.

Sporozoite immunization: innovative translational science to support the fight against malaria

INTRODUCTION

Malaria, a devastating febrile illness caused by protozoan parasites, sickened 247,000,000 people in 2021 and killed 619,000, mostly children and pregnant women in sub-Saharan Africa. A highly effective vaccine is urgently needed, especially for Plasmodium falciparum (Pf), the deadliest human malaria parasite.

AREAS COVERED

Sporozoites (SPZ), the parasite stage transmitted by Anopheles mosquitoes to humans, are the only vaccine immunogen achieving >90% efficacy against Pf infection. This review describes >30 clinical trials of PfSPZ vaccines in the U.S.A., Europe, Africa, and Asia, based on first-hand knowledge of the trials and PubMed searches of 'sporozoites,' 'malaria,' and 'vaccines.'

EXPERT OPINION

First generation (radiation-attenuated) PfSPZ vaccines are safe, well tolerated, 80-100% efficacious against homologous controlled human malaria infection (CHMI) and provide 18-19 months protection without boosting in Africa. Second generation chemo-attenuated PfSPZ are more potent, 100% efficacious against stringent heterologous (variant strain) CHMI, but require a co-administered drug, raising safety concerns. Third generation, late liver stage-arresting, replication competent (LARC), genetically-attenuated PfSPZ are expected to be both safe and highly efficacious. Overall, PfSPZ vaccines meet safety, tolerability, and efficacy requirements for protecting pregnant women and travelers exposed to Pf in Africa, with licensure for these populations possible within 5 years. Protecting children and mass vaccination programs to block transmission and eliminate malaria are long-term objectives.

Modeling malaria transmission in Nepal: impact of imported cases through cross-border mobility

The cross-border mobility of malaria cases poses an obstacle to malaria elimination programmes in many countries, including Nepal. Here, we develop a novel mathematical model to study how the imported malaria cases through the Nepal-India open-border affect the Nepal government's goal of eliminating malaria by 2026. Mathematical analyses and numerical simulations of our model, validated by malaria case data from Nepal, indicate that eliminating malaria from Nepal is possible if strategies promoting the absence of cross-border mobility, complete protection of transmission abroad, or strict border screening and isolation are implemented. For each strategy, we establish the conditions for the elimination of malaria. We further use our model to identify the control strategies that can help maintain a low endemic level. Our results show that the ideal control strategies should be designed according to the average mosquito biting rates that may depend on the location and season.

Epidemic malaria dynamics in Ethiopia: the role of self-limiting, poverty, HIV, climate change and human population growth

Background

During the last two decades, researchers have suggested that the changes of malaria cases in African highlands were driven by climate change. Recently, a study claimed that the malaria cases (Plasmodium falciparum) in Oromia (Ethiopia) were related to minimum temperature. Critics highlighted that other variables could be involved in the dynamics of the malaria. The literature mentions that beyond climate change, trends in malaria cases could be involved with HIV, human population size, poverty, investments in health control programmes, among others.

Methods

Population ecologists have developed a simple framework, which helps to explore the contributions of endogenous (density-dependent) and exogenous processes on population dynamics. Both processes may operate to determine the dynamic behaviour of a particular population through time. Briefly, density-dependent (endogenous process) occurs when the per capita population growth rate (R) is determined by the previous population size. An exogenous process occurs when some variable affects another but is not affected by the changes it causes. This study explores the dynamics of malaria cases (Plasmodium falciparum and Plasmodium vivax) in Oromia region in Ethiopia and explores the interaction between minimum temperature, HIV, poverty, human population size and social instability.

Results

The results support that malaria dynamics showed signs of a negative endogenous process between R and malaria infectious class, and a weak evidence to support the climate change hypothesis.

Conclusion

Poverty, HIV, population size could interact to force malaria models parameters explaining the dynamics malaria observed at Ethiopia from 1985 to 2007.

Effects of measures on phase transitions in two cooperative susceptible-infectious-recovered dynamics

In recent studies, it has been shown that a cooperative interaction in a co-infection spread can lead to a discontinuous transition at a decreased threshold. Here, we investigate the effects of immunization with a rate proportional to the extent of the infection on phase transitions of a cooperative co-infection. We use the mean-field approximation to illustrate how measures that remove a portion of the susceptible compartment, like vaccination, with high enough rates can change discontinuous transitions in two coupled susceptible-infectious-recovered dynamics into continuous ones while increasing the threshold of transitions. First, we introduce vaccination with a fixed rate into a symmetric spread of two diseases and investigate the numerical results. Second, we set the rate of measures proportional to the size of the infectious compartment and scrutinize the dynamics. We solve the equations numerically and analytically and probe the transitions for a wide range of parameters. We also determine transition points from the analytical solutions. Third, we adopt a heterogeneous mean-field approach to include heterogeneity and asymmetry in the dynamics and see if the results corresponding to homogeneous symmetric case stand.

Emergence of synergistic and competitive pathogens in a coevolutionary spreading model

Cooperation and competition between pathogens can alter the amount of individuals affected by a coinfection. Nonetheless, the evolution of the pathogens' behavior has been overlooked. Here, we consider a coevolutionary model where the simultaneous spreading is described by a two-pathogen susceptible-infected-recovered model in an either synergistic or competitive manner. At the end of each epidemic season, the pathogens species reproduce according to their fitness that, in turn, depends on the payoff accumulated during the spreading season in a hawk-and-dove game. This coevolutionary model displays a rich set of features. Specifically, the evolution of the pathogens' strategy induces abrupt transitions in the epidemic prevalence. Furthermore, we observe that the long-term dynamics results in a single, surviving pathogen species, and that the cooperative behavior of pathogens can emerge even under unfavorable conditions.

A Scoping Review of Drug Epidemic Models

The phenomenon of drug epidemics has been a global issue in the past decades, causing enormous damages to the physical and mental health of drug users and social well-being. Despite great efforts to curb drug epidemics at the governmental or social level, the total number of drug users has still been on the rise in recent years, along with illicit production and trafficking around the world. Inspired by dynamical epidemic models of infectious disease, a flourishment of promising results has been observed in the exploration of drug epidemic models. In this review, we aim to provide a scoping review of all existing drug epidemic modeling studies, and it has been shown that most studies focused on analyses of theoretical behaviors of the model systems, lacking emphasis on practical applications in real settings. We found that the drug epidemic models were characterized by a longer time scale, no incubation period, no significant prevention vaccines interfered, and population specificity. This review could assist policymakers and public health workers in gaining deeper insights into modeling tools, and help modelers improve their works, thus narrowing gaps between mathematical epidemiology and public health studies.

Re-emphasizing mechanism in the community ecology of disease

1. Hosts and their parasites exist within complex ecological communities. However, the role that non-focal community members, species which cannot be infected by a focal pathogen, may play in altering parasite transmission is often only studied in the lens of the "diversity-disease" relationship by focusing on species richness. This approach largely ignores mechanistic species interactions and risks collapsing our understanding of the community ecology of disease down to defining the prominence of "amplification" vs. "dilution" effects. 2. However, non-focal species vary in their traits, densities, and types of interactions with focal hosts and parasites. Therefore, a community ecology approach based on the mechanisms underlying parasite transmission, host harm, and dynamic species interactions may better advance our understanding of parasite transmission in complex communities. 3. Using the concept of the parasite's basic reproductive ratio, R0, as a generalizable framework, we examine several critical mechanisms by which interactions among hosts, parasites, and non-focal species modulate transmission and provide examples from relevant literature. 4. By focusing on the mechanism by which non-focal species impact transmission, we can emphasize the similarities among classic paradigms in the community ecology of disease, gain new insights into parasite invasion and persistence, community traits correlated with disease dilution or amplification, and the feasibility of biocontrol for parasites of conservation, agricultural, or human health concern.

A meta-analysis on the prevalence and characteristics of severe malaria in patients with Plasmodium spp. and HIV co-infection

Co-infection with malaria and human immunodeficiency virus (HIV) increases the severity and mortality rates of both diseases. A better understanding of the effects of co-infections could help in the diagnosis, prompt treatment, prevention, and control of malarial parasites among HIV-infected patients. In this systematic review and meta-analysis, we estimated the prevalence and characteristics of severe malaria (SM) caused by co-infection with HIV. We included relevant studies that were conducted between the years 1991 and 2018 and reporting on SM. We pooled the prevalence of SM in patients with co-infection, pooled odds ratios of SM in patients with co-infection and Plasmodium mono-infection, and differences in laboratory parameters such as parasite density and leucocyte counts, between co-infected and Plasmodium mono-infected patients. The meta-analysis included 29 studies (1126 SM cases). The pooled prevalence of SM in co-infected patients using the data of 23 studies (SM = 795 cases, all co-infection cases = 2534 cases) was 43.0% (95% confidence interval [CI] 31.0–56.0%; I², 98.0%). Overall, the odds of SM from 18 studies were pooled. The odds of SM were significantly higher in co-infected patients than in Plasmodium mono-infected patients (OR 2.41; 95% CI 1.43–4.08; I² = 85%; P = 0.001) and also significantly higher in children (OR 9.69; 95% CI 5.14–18.3; I², 0%; P < 0.0001; two studies) than in adults (OR 2.68; 95% CI 1.52–4.73; I², 79.0%; P = 0.0007; 12 studies). Co-infected patients with SM had a higher parasite density than those with Plasmodium mono-infection when the data of seven studies were analysed (SMD, 1.25; 95% CI 0.14–2.36; I², 98.0%; P = 0.03) and higher leukocyte counts when the data of four studies were analysed (MD, 1570 cells/µL; 95% CI 850–2300 cells/µL; I², 21.0%; P < 0.0001). Thus, the prevalence of SM among patients co-infected with Plasmodium spp. and HIV is high. Because co-infections could lead to SM, patients with Plasmodium spp. and HIV co-infection should be identified and treated to reduce the prevalence of SM and the number of deaths.

The epidemiology of psychiatric disorders in Africa: a scoping review

This scoping review of population-based epidemiological studies was done to provide background information on the prevalences and distribution of psychiatric disorders in Africa for calls to broaden diversity in psychiatric genetic studies. We searched PubMed, EMBASE, and Web of Science to retrieve relevant literature in English, French, and Portuguese from Jan 1, 1984, to Aug 18, 2020. In 36 studies from 12 African countries, the lifetime prevalence ranged from 3·3% to 9·8% for mood disorders, from 5·7% to 15·8% for anxiety disorders, from 3·7% to 13·3% for substance use disorders, and from 1·0% to 4·4% for psychotic disorders. Although the prevalence of mood and anxiety disorders appears to be lower than that observed in research outside the continent, we identified similar distributions by gender, although not by age or urbanicity. This review reveals gaps in epidemiological research on psychiatric disorders and opportunities to leverage existing epidemiological and genetic research within Africa to advance our understanding of psychiatric disorders. Studies that are methodologically comparable but diverse in geographical context are needed to advance psychiatric epidemiology and provide a foundation for understanding environmental risk in genetic studies of diverse populations globally.

The Manifesto of Pharmacoenosis: Merging HIV Pharmacology into Pathocoenosis and Syndemics in Developing Countries

Pathocoenosis and syndemics theories have emerged in the last decades meeting the frequent need of better understanding interconnections and reciprocal influences that coexistent communicable and non-communicable diseases play in a specific population. Nevertheless, the attention to pharmacokinetic and pharmacodynamics interactions of co-administered drugs for co-present diseases is to date limitedly paid to alert against detrimental pharmacological combos. Low and middle-income countries are plagued by the highest burden of HIV, tuberculosis, malaria, and helminthiasis, and they are experiencing an alarming rise in non-communicable disorders. In these settings, co-infections and comorbidities are common, but no tailored prescribing nor clinical trials are used to assess and exploit existing opportunities for the simultaneous and potentially synergistic treatment of intertwined diseases. Pharmacoenosis is the set of interactions that take place within a host as well as within a population due to the compresence of two or more diseases and their respective treatments. This framework should pilot integrated health programmes and routine clinical practice to face drug–drug interaction issues, avoiding negative co-administrations but also exploiting potential favourable ones to make the best out of the worst situations; still, to date, guiding data on the latter possibility is limited. Therefore, in this narrative review, we have briefly described both detrimental and favourable physiopathological interactions between HIV and other common co-occurring pathologies (malaria, tuberculosis, helminths, and cardiovascular disorders), and we have presented examples of advantageous potential pharmacological interactions among the drugs prescribed for these diseases from a pharmacokinetics, pharmacodynamics, and pharmacogenetics standpoint.

The Synergistic Relationship Between Climate Change and the HIV/AIDS Epidemic: A Conceptual Framework

Climate change and HIV/AIDS represent two of the greatest threats to human health in the 21st century. However, limitations in understanding the complex relationship between these syndemics continue to constrain advancements in the prevention and management of HIV/AIDS in the context of a rapidly changing climate. Here, we present a conceptual framework that identifies four pathways linking climate change with HIV/AIDS transmission and health outcomes: increased food insecurity, increased prevalence of other infectious diseases, increased human migration, and erosion of public health infrastructure. This framework is based on an in-depth literature review in PubMed and Google Scholar from June 6 to June 27, 2019. The pathways linking climate change with HIV transmission and health outcomes are complex with multiple interacting factors. Food insecurity emerged as a particularly important mediator by driving sexual risk-taking behaviours and migration, as well as by increasing susceptibility to infections that are common among people living with HIV (PLWHIV). Future interventions should focus on decreasing carbon dioxide emissions globally and increasing education and investment in adaptation strategies, particularly in those areas of sub-Saharan Africa and southeast Asia heavily impacted by both HIV and climate change. Environmentally sustainable interventions such as urban gardening and investing in sustainable agriculture technologies also have significant health co-benefits that may help PLWHIV adapt to the environmental consequences of climate change.

Prevalence and density of malaria parasitaemia amongst HIV Individuals in Warri, Nigeria

Background

Malaria parasite has been observed to be a common infection in Human Immunodeficiency virus (HIV), an increase malaria infection in adults.

Objective

This experimental study is sets to determine the prevalence and density of malaria parasitaemia in Warri community, South-Southern Nigeria.

Methods and Results

A total of 600 participants were screened for Human immunodeficiency virus and malaria parasite using WHO systems two and Geimsa staining technique for thick and thin blood films and absolute parasite counts done respectively. The prevalence rate of 38% and 39% were obtained for malaria parasite infection among HIVSP and HIV/span>SN respectively. The difference in malaria parasite infection was not statistically significant (P>0.05) between HIVSP and HIVSN. However, the mean parasite density in HIVSP was significant (P<0.05) when compared with HIVSN. The mean parasite densities of 2384 ± 747 and 1883 ± 645 were recorded for HIVSP and HIVSN respectively. The mean parasite densities of 2385 ± 782 and 2383 ± 717 observed for males and females respectively showed no statistical significant difference (P<0.05).

Conclusion

This study has shown a high prevalence of malaria parasite among the HIV infected subjects.

Natural resistance to worms exacerbates bovine tuberculosis severity independently of worm coinfection

Pathogen interactions arising during coinfection can exacerbate disease severity, for example when the immune response mounted against one pathogen negatively affects defense of another. It is also possible that host immune responses to a pathogen, shaped by historical evolutionary interactions between host and pathogen, may modify host immune defenses in ways that have repercussions for other pathogens. In this case, negative interactions between two pathogens could emerge even in the absence of concurrent infection. Parasitic worms and tuberculosis (TB) are involved in one of the most geographically extensive of pathogen interactions, and during coinfection worms can exacerbate TB disease outcomes. Here, we show that in a wild mammal natural resistance to worms affects bovine tuberculosis (BTB) severity independently of active worm infection. We found that worm-resistant individuals were more likely to die of BTB than were nonresistant individuals, and their disease progressed more quickly. Anthelmintic treatment moderated, but did not eliminate, the resistance effect, and the effects of resistance and treatment were opposite and additive, with untreated, resistant individuals experiencing the highest mortality. Furthermore, resistance and anthelmintic treatment had nonoverlapping effects on BTB pathology. The effects of resistance manifested in the lungs (the primary site of BTB infection), while the effects of treatment manifested almost entirely in the lymph nodes (the site of disseminated disease), suggesting that resistance and active worm infection affect BTB progression via distinct mechanisms. Our findings reveal that interactions between pathogens can occur as a consequence of processes arising on very different timescales.

Analytic Characterization of the Herpes Simplex Virus Type 2 Epidemic in the United States, 1950-2050

Background

We analytically characterized the past, present, and future levels and trends of the national herpes simplex virus type 2 (HSV-2) epidemic in the United States.

Methods

A population-level mathematical model was constructed to describe HSV-2 transmission dynamics and was fitted to the data series of the National Health and Nutrition Examination Survey.

Results

Over 1950–2050, antibody prevalence (seroprevalence) increased rapidly from 1960, peaking at 19.9% in 1983 in those aged 15–49 years, before reversing course to decline to 13.2% by 2020 and 8.5% by 2050. Incidence rate peaked in 1971 at 11.9 per 1000 person-years, before declining by 59% by 2020 and 70% by 2050. Annual number of new infections peaked at 1 033 000 in 1978, before declining to 667 000 by 2020 and 600 000 by 2050. Women were disproportionately affected, averaging 75% higher seroprevalence, 95% higher incidence rate, and 71% higher annual number of infections. In 2020, 78% of infections were acquired by those 15–34 years of age.

Conclusions

The epidemic has undergone a major transition over a century, with the greatest impact in those 15–34 years of age. In addition to 47 million prevalent infections in 2020, high incidence will persist over the next 3 decades, adding >600 000 new infections every year.

Yin and yang of immunological memory in controlling infections: Overriding self defence mechanisms

Immunological memory is critical for host immunity and decisive for individual to respond exponentially to previously encountered infection. Both T and B cell memory are known to orchestrate immunological memory with their central and effector memory arms contributing in prolonged immunity/defence mechanisms of host. While central memory helps in maintaining prolonged immunity for a particular infection, effector memory helps in keeping local/seasonal infection in control. In addition to this, generation of long-lived plasma cells is pivotal for generating neutralizing antibodies which can enhance recall and B cell memory to control re-infection. In view of this, scaling up memory response is one of the major objectives for the expected outcome of vaccination. In this line, this review deals with the significance of memory cells, molecular pathways of their development, maintenance, epigenetic regulation and negative regulation in various infections. We have also highlighted the significance of both T and B cell memory responses in the vaccination approaches against range of infections which is not fully explored so far.[Box: see text].

HIV-1 Impact on Malaria Transmission: A Complex and Relevant Global Health Concern

Malaria/HIV-1 co-infection has become a significant public health problem in the tropics where there is geographical overlap of the two diseases. It is well described that co-infection impacts clinical progression of both diseases; however, less is known about the impact of co-infection on disease transmission. Malaria transmission is dependent upon multiple critical factors, one of which is the presence and viability of the sexual-stage gametocyte. In this review, we summarize evidence surrounding gametocyte production in Plasmodium falciparum and the development factors and the consequential impact that HIV-1 has on malaria parasite transmission. Epidemiological and clinical evidence surrounding anemia, immune dysregulation, and chemotherapy as it pertains to co-infection and gametocyte transmission are reviewed. We discuss significant gaps in understanding that are often due to the biological complexities of both diseases as well as the lack of entomological data necessary to define transmission success. In particular, we highlight special epidemiological populations, such as co-infected asymptomatic gametocyte carriers, and the unique role these populations have in a future focused on malaria elimination and eradication.

Spiro-β-lactam BSS-730A Displays Potent Activity against HIV and Plasmodium

The high burden of malaria and HIV/AIDS prevents economic and social progress in developing countries. A continuing need exists for development of novel drugs and treatment regimens for both diseases in order to address the tolerability and long-term safety concerns associated with current treatment options and the emergence of drug resistance. We describe new spiro-β-lactam derivatives with potent (nM) activity against HIV and Plasmodium and no activity against bacteria and yeast. The best performing molecule of the series, BSS-730A, inhibited both HIV-1 and HIV-2 replication with an IC₅₀ of 13 ± 9.59 nM and P. berghei hepatic infection with an IC₅₀ of 0.55 ± 0.14 μM with a clear impact on parasite development. BSS-730A was also active against the erythrocytic stages of P. falciparum, with an estimated IC₅₀ of 0.43 ± 0.04 μM. Time-of-addition studies showed that BSS-730A potentially affects all stages of the HIV replicative cycle, suggesting a complex mechanism of action. BSS-730A was active against multidrug-resistant HIV isolates, with a median 2.4-fold higher IC₅₀ relative to control isolates. BSS-730A was equally active against R5 and X4 HIV isolates and displayed strong synergism with the entry inhibitor AMD3100. BSS-730A is a promising candidate for development as a potential therapeutic and/or prophylactic agent against HIV and Plasmodium.

Should we care about Plasmodium vivax and HIV co-infection? A systematic review and a cases series from the Brazilian Amazon

BACKGROUND

Malaria and HIV are two important public health issues. However, evidence on HIV-Plasmodium vivax co-infection (HIV/PvCo) is scarce, with most of the available information related to Plasmodium falciparum on the African continent. It is unclear whether HIV can change the clinical course of vivax malaria and increase the risk of complications. In this study, a systematic review of HIV/PvCo studies was performed, and recent cases from the Brazilian Amazon were included.

METHODS

Medical records from a tertiary care centre in the Western Brazilian Amazon (2009-2018) were reviewed to identify HIV/PvCo hospitalized patients. Demographic, clinical and laboratory characteristics and outcomes are reported. Also, a systematic review of published studies on HIV/PvCo was conducted. Metadata, number of HIV/PvCo cases, demographic, clinical, and outcome data were extracted.

RESULTS

A total of 1,048 vivax malaria patients were hospitalized in the 10-year period; 21 (2.0%) were HIV/PvCo cases, of which 9 (42.9%) had AIDS-defining illnesses. This was the first malaria episode in 11 (52.4%) patients. Seven (33.3%) patients were unaware of their HIV status and were diagnosed on hospitalization. Severe malaria was diagnosed in 5 (23.8%) patients. One patient died. The systematic review search provided 17 articles (12 cross-sectional or longitudinal studies and 5 case report studies). A higher prevalence of studies involved cases in African and Asian countries (35.3 and 29.4%, respectively), and the prevalence of reported co-infections ranged from 0.1 to 60%.

CONCLUSION

Reports of HIV/PvCo are scarce in the literature, with only a few studies describing clinical and laboratory outcomes. Systematic screening for both co-infections is not routinely performed, and therefore the real prevalence of HIV/PvCo is unknown. This study showed a low prevalence of HIV/PvCo despite the high prevalence of malaria and HIV locally. Even though relatively small, this is the largest case series to describe HIV/PvCo.

The Syndemics and Structural Violence of the COVID Pandemic: Anthropological Insights on a Crisis

This paper examines the COVID-19 pandemic in light of two key concepts in medical anthropology: syndemics and structural violence. Following a discussion of the nature of these two concepts, the paper addresses the direct and associated literatures on the syndemic and structural violence features of the COVID pandemic, with a specific focus on: 1) the importance of local socioenvironmental conditions/demographics and disease configurations in creating varying local syndemic expressions; 2) the ways that the pandemic has exposed the grave weaknesses in global health care investment; and 3) how the syndemic nature of the pandemic reveals the rising rate of noncommunicable diseases and their potential for interaction with current and future infectious disease. The paper concludes with a discussion on the role of anthropology in responding to COVID-19 from a syndemics perspective.

Coinfection dynamics of heroin transmission and HIV infection in a single population

We propose a model of a joint spread of heroin use and HIV infection. The unique disease-free equilibrium always exists and it is stable if the basic reproduction numbers of heroin use and HIV infection are both less than 1. The semi-trivial equilibrium of HIV infection (heroin use) exists if the basic reproduction number of HIV infection (heroin use) is larger than 1 and it is locally stable if and only if the invasion number of heroin use (HIV infection) is less than 1. When both semi-trivial equilibria lose their stability, a coexistence equilibrium occurs, which may not be unique. We compare the model to US data on heroin use and HIV transmission. We conclude that the two diseases in the US are in a coexistence regime. Elasticities of the invasion numbers suggest two foci for control measures: targeting the drug abuse epidemic and reducing HIV risk in drug-users.

Malaria and HIV Infection among Febrile Patients in a Large Area of Southwestern Nigeria

Background: Malaria and HIV/AIDS are two major diseases that represent serious public health threats in Nigeria. They have been ascribed diseases of poverty, and therefore their distribution is expected to be overlapping.

Aim: The aim of this study was to determine the prevalence of malaria parasites and HIV among febrile patients in the Ikeja area of Lagos State, Nigeria.

Materials and Methods: The study was conducted on 300 patients attending medical consultation and referred to blood screening for malaria parasites at Reddington Hospital, Lagos State. Malaria parasites were identified microscopically, and HIV screening was carried out using rapid diagnostic tests (RDT).

Results: The prevalence of malaria and HIV was 98.7% and 3.7%, respectively. All HIV-positive individuals were also infected by malaria parasites. Mean parasitemia was significantly higher in HIV-positive individuals (16,507.9 ± 2,280.7 P/μL) than in HIV-negative subjects (3,252.505 ± 236.3 P/μL) (p <0.05).

Conclusions: Our results suggest that HIV-infected individuals are more susceptible to infection with malaria parasites. Prompt HIV management is necessary in malaria-endemic areas to reduce disease severity in case of coinfection with HIV.

Associations of malaria, HIV, and coinfection, with anemia in pregnancy in sub-Saharan Africa: a population-based cross-sectional study

BACKGROUND

Malaria and HIV are common infections in Africa and cause substantial morbidity and mortality in pregnant women. We aimed to assess the association of malaria with anemia in pregnant women and to explore the joint effects of malaria and HIV infection on anemia in pregnant women.

METHODS

We used nationally representative, cross-sectional demographic and health surveys (DHS) that were conducted between 2012 and 2017 across 7 countries of sub-Saharan Africa (Burundi, the Democratic Republic of the Congo, Gambia, Ghana, Mali, Senegal and Togo). The outcome variables were anemia (defined as a hemoglobin concentration < 110 g/L), and hemoglobin concentration on a continuous scale, in pregnant women at the time of the interview. We used generalized linear mixed-effects models to account for the nested structure of the data. We adjusted models for individual covariates, with random effects of the primary sampling unit nested within a country.

RESULTS

A total of 947 pregnant women, ages, 15-49 y, were analyzed. Prevalence of malaria only, HIV only, and malaria- HIV coinfection in pregnant women was 31% (95% CI: 28.5 to 34.5%, n = 293), 1.3% (95% CI: 0.77 to 2.4%, n = 13) and 0.52% (95% CI: 0.02 to 1.3%, n = 5) respectively. Overall prevalence of anemia was 48.3% (95% CI: 45.1 to 51.5%). The anemia prevalence in pregnant women with malaria infection only was 56.0% (95% CI: 50.1 to 61.7%); HIV infection only, 62.5% (95% CI: 25.9 to 89.8%); malaria- HIV coinfection, 60.0 (95% CI: 17.0-92.7%) and without either infection, 44.6% (95% CI: 40.7 to 48.6%). In the fully adjusted models, malaria infection was associated with 27% higher prevalence of anemia (95% CI of prevalence ratio: 1.12 to 1.45; p = 0.004), and 3.4 g/L lower hemoglobin concentration (95% CI: - 5.01 to - 1.79; p = 0.03) compared to uninfected pregnant women. The prevalence of HIV infection and malaria-HIV coinfection was too low to allow meaningful analysis of their association with anemia or hemoglobin concentration.

CONCLUSION

Malaria was associated with an increased prevalence of anemia during pregnancy.

Human immunodeficiency virus is a driven factor of human papilloma virus among women: evidence from a cross-sectional analysis in Yaoundé, Cameroon

BACKGROUND

Human papillomavirus (HPV) is the leading cause of cervical cancers, causing 270.000 deaths annually worldwide of which 85% occur in developing countries with an increasing risk associated to HIV infection. This study aimed at comparing HPV's positivity and genotype distribution in women according to their HIV status and determinants.

METHODS

A comparative study was carried out in 2012 at the Chantal BIYA International Reference Centre (CIRCB) among 278 women enrolled consecutively at the General Hospital and the Gynaeco-Obstetric and Paediatric Hospital of the City of Yaoundé. HPV genotyping was performed by real-time PCR, HIV serological screening by serial algorithm, CD4 T cell phenotyping by flow cytometry and HIV viral load by Abbott m2000RT. Statistical analyses were performed using Microsoft Excel 2016 and Graph Pad version 6.0 software; with P < 0.05 considered statistically significant.

RESULTS

Globally, mean age was 37 ± 3 years; median CD4-count for HIV+ was 414 cells/mm3 [IQR: 264.75-588] and median viremia was 50 RNA copies/mL [IQR: < 40-8288]. Overall HPV rate was 38.49% (107/278); 58.88% for single women vs. others (28.97% married, 2.80% divorced, 9.34% for widows), OR: 2.164; p = 0.0319. Following HIV status, HPV rate was 43.48% (80/184) among HIV+ vs. 28.72% (27/94) among HIV- (OR: 1.937; p < 0.0142); HPV genotypes among HIV+ vs. HIV- were respectively distributed as follows: genotype 16 (3.75% vs. 0.00%, p = 0.57), genotype 18 (3.75% vs. 3.70%, p = 1.00), co-infection 16 and others (8.75% vs. 7.40%, p = 1.00), co-infection 18 and others (8.75% vs. 11.11%, p = 0.71), co-infection 16, 18 and others (2.50% vs. 0.00%, p = 1.00) and other genotypes (72.50% vs. 77.78%, p = 0.80). Among HIV+ participants, HPV rate following CD4 was 62.88% (61/97) for CD4 < 500 vs. 35.71% (20/56) for CD4 ≥ 500 (OR: 3.05; p = 0.0012) while HPV rate following HIV viremia was 42.71% (41/96) with < 1000 RNA copies/ml vs. 66.00% (33/50) with > 1000 RNA copies/ml (OR = 0.384; p = 0.009).

CONCLUSION

In Yaoundé, HPV rate appear to be very high, with higher rates of genotypes other than 16 and 18. In the event of HIV infection, the risk of HPV positivity is two times higher, favoured essentially by immunodeficiency. Thus, HIV-infected women should be closely monitored to prevent the emergence of cervical cancer.

Malaria Parasite Density as a Predictor of Hematological Parameter Changes among HIV Infected Adults Attending Two Antiretroviral Treatment Clinics in Kano, Northwest Nigeria

Background

Despite public health significance of dual infections of human immunodeficiency virus (HIV) and malaria in developing countries like Nigeria, information on the association between malaria parasite density count (MPDC) and hematological parameter changes among HIV-infected individuals is rarely available.

Objectives

To evaluate burden of HIV and malaria dual infections and assess the predictive association of MPDC with hematological parameter changes among HIV infected adults attending two antiretroviral treatment clinics in Kano, Nigeria. Methodology. This was a cross-sectional study consisting of 1521 consented participants randomly selected between June 2015 and May 2016. Participants' basic characteristics and clinical details were collected using a pretested and validated standardized questionnaire. Collected venous blood was analyzed for malaria by rapid testing and microscopy including malaria parasite density; hematological parameters were estimated using a Sysmex XP-300 autoanalyzer. Data was reviewed, cleaned, and analyzed using SPSS software version 23.0. Mean hematological parameters and HIV/malaria status were compared using the independent t-test; hematological parameters and MPDC relationship was tested by simple linear regression analysis. Statistically significant difference at probability of <0.05 was considered for all variables.

Results

The majority (70.6%) of the participants were females. Mean (SD) age was 37.30 ± (10.41) years and ranged from 18 to 78 years. 25.4% of participants had dual infection, 99% due to Plasmodium falciparum species. Mean MPDC was 265 ± 31.8 (SD) cells/μl and ranged from 20 to 2500 cells/μl. Dual infection was highest (37.5%) among respondents in the age group ≥60 years. Prevalence was similar among other age groups (p = 0.165) and gender (p = 0.942). Of the 16 hematological parameters evaluated, 11 showed significant difference between HIV mono-infected and dual infected participants. Of the 11 parameters, only 7 (Hb, MCHC, red cells count, neutrophil and lymphocyte percentage, absolute lymphocyte count, and red cell distribution width) were significantly predictive of changes with respect to MPDC.

Conclusions

MPDC was significantly predictive of changes in 7 hematological parameters among dual infected participants in these settings. In routine malaria diagnosis, MPDC determination with respect to changes in some hematological parameters should be considered in ART programs for improved patient management.

Mathematical Analysis of the Ross-Macdonald Model with Quarantine

People infected with malaria may receive less mosquito bites when they are treated in well-equipped hospitals or follow doctors’ advice for reducing exposure to mosquitoes at home. This quarantine-like intervention measure is especially feasible in countries and areas approaching malaria elimination. Motivated by mathematical models with quarantine for directly transmitted diseases, we develop a mosquito-borne disease model where imperfect quarantine is considered to mitigate the disease transmission from infected humans to susceptible mosquitoes. The basic reproduction number \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {R}_0$$\end{document}R0 is computed and the model equilibria and their stabilities are analyzed when the incidence rate is standard or bilinear. In particular, the model system may undergo a subcritical (backward) bifurcation at \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {R}_0=1$$\end{document}R0=1 when standard incidence is adopted, whereas the disease-free equilibrium is globally asymptotically stable as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {R}_0\le 1$$\end{document}R0≤1 and the unique endemic equilibrium is locally asymptotically stable as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {R}_0>1$$\end{document}R0>1 when the infection incidence is bilinear. Numerical simulations suggest that the quarantine strategy can play an important role in decreasing malaria transmission. The success of quarantine mainly relies on the reduction of bites on quarantined individuals.

Variation in Local and Systemic Pro-Inflammatory Immune Markers of Wild Wood Mice after Anthelmintic Treatment

The immune system represents a host's main defense against infection to parasites and pathogens. In the wild, a host's response to immune challenges can vary due to physiological condition, demography (age, sex), and coinfection by other parasites or pathogens. These sources of variation, which are intrinsic to natural populations, can significantly impact the strength and type of immune responses elicited after parasite exposure and infection. Importantly, but often neglected, a host's immune response can also vary within the individual, across tissues and between local and systemic scales. Consequently, how a host responds at each scale may impact its susceptibility to concurrent and subsequent infections. Here we analyzed how characteristics of hosts and their parasite infections drive variation in the pro-inflammatory immune response in wild wood mice (Apodemus sylvaticus) at both the local and systemic scale by experimentally manipulating within-host parasite communities through anthelmintic drug treatment. We measured concentrations of the pro-inflammatory cytokine tumor necrosis factor alpha (TNF-α) produced in vitro in response to a panel of toll-like receptor agonists at the local (mesenteric lymph nodes [MLNs]) and systemic (spleen) scales of individuals naturally infected with two gastrointestinal parasites, the nematode Heligmosomoides polygyrus and the protozoan Eimeria hungaryensis. Anthelmintic-treated mice had a 20-fold lower worm burden compared to control mice, as well as a four-fold higher intensity of the non-drug targeted parasite E. hungaryensis. Anthelmintic treatment differentially impacted levels of TNF-α expression in males and females at the systemic and local scales, with treated males producing higher, and treated females lower, levels of TNF-α, compared to control mice. Also, TNF-α was affected by host age, at the local scale, with MLN cells of young, treated mice producing higher levels of TNF-α than those of old, treated mice. Using complementary, but distinct, measures of inflammation measured across within-host scales allowed us to better assess the wood mouse immune response to changes in parasite infection dynamics after anthelmintic treatment. This same approach could be used to understand helminth infections and responses to parasite control measures in other systems in order to gain a broader view of how variation impacts the immune response.

Within-host priority effects and epidemic timing determine outbreak severity in co-infected populations

Co-infections of hosts by multiple pathogen species are ubiquitous, but predicting their impact on disease remains challenging. Interactions between co-infecting pathogens within hosts can alter pathogen transmission, with the impact on transmission typically dependent on the relative arrival order of pathogens within hosts (within-host priority effects). However, it is unclear how these within-host priority effects influence multi-pathogen epidemics, particularly when the arrival order of pathogens at the host-population scale varies. Here, we combined models and experiments with zooplankton and their naturally co-occurring fungal and bacterial pathogens to examine how within-host priority effects influence multi-pathogen epidemics. Epidemiological models parametrized with within-host priority effects measured at the single-host scale predicted that advancing the start date of bacterial epidemics relative to fungal epidemics would decrease the mean bacterial prevalence in a multi-pathogen setting, while models without within-host priority effects predicted the opposite effect. We tested these predictions with experimental multi-pathogen epidemics. Empirical dynamics matched predictions from the model including within-host priority effects, providing evidence that within-host priority effects influenced epidemic dynamics. Overall, within-host priority effects may be a key element of predicting multi-pathogen epidemic dynamics in the future, particularly as shifting disease phenology alters the order of infection within hosts.

Social immunity modulates competition between coinfecting pathogens

Coinfections with multiple pathogens can result in complex within-host dynamics affecting virulence and transmission. While multiple infections are intensively studied in solitary hosts, it is so far unresolved how social host interactions interfere with pathogen competition, and if this depends on coinfection diversity. We studied how the collective disease defences of ants - their social immunity - influence pathogen competition in coinfections of same or different fungal pathogen species. Social immunity reduced virulence for all pathogen combinations, but interfered with spore production only in different-species coinfections. Here, it decreased overall pathogen sporulation success while increasing co-sporulation on individual cadavers and maintaining a higher pathogen diversity at the community level. Mathematical modelling revealed that host sanitary care alone can modulate competitive outcomes between pathogens, giving advantage to fast-germinating, thus less grooming-sensitive ones. Host social interactions can hence modulate infection dynamics in coinfected group members, thereby altering pathogen communities at the host level and population level.

Synchronous shedding of multiple bat paramyxoviruses coincides with peak periods of Hendra virus spillover

Within host-parasite communities, viral co-circulation and co-infections of hosts are the norm, yet studies of significant emerging zoonoses tend to focus on a single parasite species within the host. Using a multiplexed paramyxovirus bead-based PCR on urine samples from Australian flying foxes, we show that multi-viral shedding from flying fox populations is common. We detected up to nine bat paramyxoviruses shed synchronously. Multi-viral shedding infrequently coalesced into an extreme, brief and spatially restricted shedding pulse, coinciding with peak spillover of Hendra virus, an emerging fatal zoonotic pathogen of high interest. Such extreme pulses of multi-viral shedding could easily be missed during routine surveillance yet have potentially serious consequences for spillover of novel pathogens to humans and domestic animal hosts. We also detected co-occurrence patterns suggestive of the presence of interactions among viruses, such as facilitation and cross-immunity. We propose that multiple viruses may be interacting, influencing the shedding and spillover of zoonotic pathogens. Understanding these interactions in the context of broader scale drivers, such as habitat loss, may help predict shedding pulses of Hendra virus and other fatal zoonoses.

Interplay between competitive and cooperative interactions in a three-player pathogen system

In ecological systems, heterogeneous interactions between pathogens take place simultaneously. This occurs, for instance, when two pathogens cooperate, while at the same time, multiple strains of these pathogens co-circulate and compete. Notable examples include the cooperation of human immunodeficiency virus with antibiotic-resistant and susceptible strains of tuberculosis or some respiratory infections with Streptococcus pneumoniae strains. Models focusing on competition or cooperation separately fail to describe how these concurrent interactions shape the epidemiology of such diseases. We studied this problem considering two cooperating pathogens, where one pathogen is further structured in two strains. The spreading follows a susceptible-infected-susceptible process and the strains differ in transmissibility and extent of cooperation with the other pathogen. We combined a mean-field stability analysis with stochastic simulations on networks considering both well-mixed and structured populations. We observed the emergence of a complex phase diagram, where the conditions for the less transmissible, but more cooperative strain to dominate are non-trivial, e.g. non-monotonic boundaries and bistability. Coupled with community structure, the presence of the cooperative pathogen enables the coexistence between strains by breaking the spatial symmetry and dynamically creating different ecological niches. These results shed light on ecological mechanisms that may impact the epidemiology of diseases of public health concern.

Impact of Endemic Infections on HIV Susceptibility in Sub-Saharan Africa

Human immunodeficiency virus (HIV) remains a leading cause of global morbidity with the highest burden in Sub-Saharan Africa (SSA). For reasons that are incompletely understood, the likelihood of HIV transmission is several fold higher in SSA than in higher income countries, and most of these infections are acquired by young women. Residents of SSA are also exposed to a variety of endemic infections, such as malaria and various helminthiases that could influence mucosal and systemic immunology. Since these immune parameters are important determinants of HIV acquisition and progression, this review explores the possible effects of endemic infections on HIV susceptibility and summarizes current knowledge of the epidemiology and underlying immunological mechanisms by which endemic infections could impact HIV acquisition. A better understanding of the interaction between endemic infections and HIV may enhance HIV prevention programs in SSA.

Tissue Parasites in HIV Infection

PURPOSE OF REVIEW

The purpose of this review is to discuss the current knowledge of HIV and tissue parasite co-infection in the context of transmission enhancement, clinical characteristics, treatment, relapse, and clinical outcomes.

RECENT FINDINGS

The pathophysiology and clinical sequelae of tissue parasites in people living with HIV (PLWH) have been well described for only a handful of organisms, primarily protozoa such as malaria and leishmaniasis. Available published data indicate that the interactions between HIV and tissue parasites are highly variable depending on the infecting organism and the degree of host immunosuppression. Some tissue parasites, such as Schistosoma species, are known to facilitate the transmission of HIV. Conversely, uncontrolled HIV infection can lead to the earlier and more severe presentation of a variety of tissue parasites and can make treatment more challenging. Although much investigation remains to be done to better understand the interactions between consequences of HIV and tissue parasite co-infection, it is important to disseminate the current knowledge on this topic to health care providers in order to prevent, treat, and control infections in PLWH.

HIV infection drives IgM and IgG3 subclass bias in Plasmodium falciparum-specific and total immunoglobulin concentration in Western Kenya

Background

HIV infection is associated with more frequent and severe episodes of malaria and may be the result of altered malaria-specific B cell responses. However, it is poorly understood how HIV and the associated lymphopenia and immune activation affect malaria-specific antibody responses.

Methods

HIV infected and uninfected adults were recruited from Bondo subcounty hospital in Western Kenya at the time of HIV testing (antiretroviral and co-trimoxazole prophylaxis naïve). Total and Plasmodium falciparum apical membrane antigen-1 (AMA1) and glutamate rich protein-R0 (GLURP-R0) specific IgM, IgG and IgG subclass concentrations was measured in 129 and 52 of recruited HIV-infected and uninfected individuals, respectively. In addition, HIV-1 viral load (VL), CD4⁺ T cell count, and C-reactive protein (CRP) concentration was quantified in study participants. Antibody levels were compared based on HIV status and the associations of antibody concentration with HIV-1 VL, CD4⁺ count, and CRP levels was measured using Spearman correlation testing.

Results

Among study participants, concentrations of IgM, IgG1 and IgG3 antibodies to AMA1 and GLURP-R0 were higher in HIV infected individuals compared to uninfected individuals (all p < 0.001). The IgG3 to IgG1 ratio to both AMA1 and GLURP-R0 was also significantly higher in HIV-infected individuals (p = 0.02). In HIV-infected participants, HIV-1 VL and CRP were weakly correlated with AMA1 and GLURP-R0 specific IgM and IgG1 concentrations and total (not antigen specific) IgM, IgG, IgG1, and IgG3 concentrations (all p < 0.05), suggesting that these changes are related in part to viral load and inflammation.

Conclusions

Overall, HIV infection leads to a total and malaria antigen-specific immunoglobulin production bias towards higher levels of IgM, IgG1, and IgG3, and HIV-1 viraemia and systemic inflammation are weakly correlated with these changes. Further assessments of antibody affinity and function and correlation with risk of clinical malaria, will help to better define the effects of HIV infection on clinical and biological immunity to malaria.

Coevolution spreading in complex networks

The propagations of diseases, behaviors and information in real systems are rarely independent of each other, but they are coevolving with strong interactions. To uncover the dynamical mechanisms, the evolving spatiotemporal patterns and critical phenomena of networked coevolution spreading are extremely important, which provide theoretical foundations for us to control epidemic spreading, predict collective behaviors in social systems, and so on. The coevolution spreading dynamics in complex networks has thus attracted much attention in many disciplines. In this review, we introduce recent progress in the study of coevolution spreading dynamics, emphasizing the contributions from the perspectives of statistical mechanics and network science. The theoretical methods, critical phenomena, phase transitions, interacting mechanisms, and effects of network topology for four representative types of coevolution spreading mechanisms, including the coevolution of biological contagions, social contagions, epidemic-awareness, and epidemic-resources, are presented in detail, and the challenges in this field as well as open issues for future studies are also discussed.

Thiosemicarbazone derivatives: Design, synthesis and in vitro antimalarial activity studies

Different types of thiosemicarbazone derivatives were designed and tested for their Drug-Like Molecular (DLM) nature by using Lipinski and Veber rules. Subsequently, compounds with DLM properties were synthesized and characterized by spectral methods. In vitro antimalarial activity studies of the synthesized thiosemicarbazone derivatives have been carried out against Plasmodium falciparum, 3D7 strain using fluorescence assay method and found that the compounds, (E)-2-(1-(4-fluorophenyl)ethylidene)hydrazine-1-carbothioamide (6), (E)-2-(1-(3-bromophenyl) ethylidene) hydrazine-1-carbothioamide (15) and (E)-2-(3,4,5-trimethoxybenzylidene) hydrazine-1-carbothioamide (29) showed notable antimalarial activity with EC₅₀ values of 13.54 μM, 15.83 μM and 14.52 μM respectively.

Detecting within-host interactions from genotype combination prevalence data

Parasite genetic diversity can provide information on disease transmission dynamics but most mathematical and statistical frameworks ignore the exact combinations of genotypes in infections. We introduce and validate a new method that combines explicit epidemiological modelling of coinfections and regression-Approximate Bayesian Computing (ABC) to detect within-host interactions. Using a susceptible-infected-susceptible (SIS) model, we show that, if sufficiently strong, within-host parasite interactions can be detected from epidemiological data. We also show that, in this simple setting, this detection is robust even in the face of some level of host heterogeneity in behaviour. These simulations results offer promising applications to analyse large datasets of multiple infection prevalence data, such as those collected for genital infections by Human Papillomaviruses (HPVs).

Submicroscopic Plasmodium falciparum parasitaemia in human immunodeficiency virus-infected adults living in Gabon (Central Africa)-a pilot study

Background

Submicroscopic malaria infections contribute to malaria transmission. Describing the extent of the parasite reservoir is of importance. In people living with human immunodeficiency virus (HIV), the frequency of subpatent malaria infections is rarely reported. The aim of the present study was to determine the frequency of submicroscopic infections in people living with HIV in Gabon and its relationship with cotrimoxazole (CTX) use.

Methods

A survey was conducted in two health care centres in rural areas (Koulamoutou and Oyem) and three in urban areas (Libreville) of Gabon from March 2015 to June 2016. Blood samples were collected from consenting people living with HIV with a negative blood smear. Information on CTX and antiretroviral therapy intake was recorded from the medical file of the patient and through an interview. For molecular analysis, the Plasmodium small subunit ribosomal RNA gene was amplified by nested polymerase chain reaction.

Results

Submicroscopic infections were detected in 10.1% (n=12/119) of the people living with HIV, more frequently in those residing in rural areas (15.1%) compared with urban areas (2.1%) (p<0.01). The proportion of anaemic patients was 1.74-fold more frequent in malaria-infected patients, although not statistically significant. Submicroscopic infections frequency did not vary according to CTX intake (p=0.6).

Conclusions

The present pilot study highlights a non-negligible frequency of submicroscopic malaria infections in people living with HIV from rural areas, but no relationship with CTX intake was found.

Malaria care-seeking behaviour among HIV-infected patients receiving antiretroviral treatment in South-Eastern Nigeria: A cross-sectional study

This study assesses malaria prevention and treatment behaviour among people living with HIV/AIDS (PLWHA) in Owerri, South Eastern Nigeria. Although Nigeria bears one of the world’s largest burdens of both malaria and HIV, there is almost no research studying how co-infected patients manage their care. We systematically sampled 398 PLWHA receiving care at Imo State Specialist Hospital and the Federal Medical Centre in Owerri to complete a structured, pre-tested questionnaire on malaria care-seeking behaviour. Descriptive statistics were reported and chi-square tests and multivariate logistic regressions were also used. The majority of HIV-infected patients (78.9%) reported having had an episode of suspected malaria quarterly or more often. There was a large variation in care-seeking patterns: on suspicion of malaria, 29.1% of participants engaged in self-medication; 39.2% went to drug shops, and only 22.6% visited HIV/AIDS care centres. Almost 40% waited more than 24 hours before initiating treatment. Most (60.3%), reported taking recommended artemisinin-based combination treatments (ACT) but a significant minority took only paracetamol (25.6%) or herbal remedies (3.5%). Most (80%) finished their chosen course of treatment; and completion of treatment was significantly associated with the frequency of suspected malaria occurrence (p = 0.03). Most (62.8%) did not take anti-malaria medication while taking antiretroviral treatment (ART) and almost all (87.6%) reported taking an ACT regimen that could potentially interact with Nigeria’s first-line ART regimen. Our findings suggest the need to pay more attention to malaria prevention and control as a crucial element in HIV/AIDS management in this part of Nigeria and other areas where malaria and HIV/AIDS are co-endemic. Also, more research on ART-ACT interactions, better outreach to community-level drug shops and other private sector stakeholders, and clearer guidelines for clinicians and patients on preventing and managing co-infection may be needed. This will require improved collaboration between programmes for both diseases.

Endemicity and prevalence of multipartite viruses under heterogeneous between-host transmission

Multipartite viruses replicate through a puzzling evolutionary strategy. Their genome is segmented into two or more parts, and encapsidated in separate particles that appear to propagate independently. Completing the replication cycle, however, requires the full genome, so that a systemic infection of a host requires the concurrent presence of several particles. This represents an apparent evolutionary drawback of multipartitism, while its advantages remain unclear. A transition from monopartite to multipartite viral forms has been described in vitro under conditions of high multiplicity of infection, suggesting that cooperation between defective mutants is a plausible evolutionary pathway towards multipartitism. However, it is unknown how the putative advantages that multipartitism might enjoy at the microscopic level affect its epidemiology, or if an explicit advantange is needed to explain its ecological persistence. In order to disentangle which mechanisms might contribute to the rise and fixation of multipartitism, we here investigate the interaction between viral spreading dynamics and host population structure. We set up a compartmental model of the spread of a virus in its different forms and explore its epidemiology using both analytical and numerical techniques. We uncover that the impact of host contact structure on spreading dynamics entails a rich phenomenology of ecological relationships that includes cooperation, competition, and commensality. Furthermore, we find out that multipartitism might rise to fixation even in the absence of explicit microscopic advantages. Multipartitism allows the virus to colonize environments that could not be invaded by the monopartite form, while homogeneous contacts between hosts facilitate its spread. We conjecture that these features might have led to an increase in the diversity and prevalence of multipartite viral forms concomitantly with the expansion of agricultural practices.