Artificial Feeding Systems for Vector-Borne Disease Studies.

This review examines the advancements and methodologies of artificial feeding systems for the study of vector-borne diseases, offering a critical assessment of their development, advantages, and limitations relative to traditional live host models. It underscores the ethical considerations and practical benefits of such systems, including minimizing the use of live animals and enhancing experimental consistency. Various artificial feeding techniques are detailed, including membrane feeding, capillary feeding, and the utilization of engineered biocompatible materials, with their respective applications, efficacy, and the challenges encountered with their use also being outlined. This review also forecasts the integration of cutting-edge technologies like biomimicry, microfluidics, nanotechnology, and artificial intelligence to refine and expand the capabilities of artificial feeding systems. These innovations aim to more accurately simulate natural feeding conditions, thereby improving the reliability of studies on the transmission dynamics of vector-borne diseases. This comprehensive review serves as a foundational reference for researchers in the field, proposing a forward-looking perspective on the potential of artificial feeding systems to revolutionize vector-borne disease research.

Mosquito Salivary Antigens and Their Relationship to Dengue and P. vivax Malaria.

In tropical areas, the simultaneous transmission of multiple vector-borne diseases is common due to ecological factors shared by arthropod vectors. Malaria and dengue virus, transmitted by Anopheles and Aedes mosquitoes, respectively, are among the top vector-borne diseases that cause significant morbidity and mortality in endemic areas. Notably, tropical areas often have suitable conditions for the co-existence of these mosquito species, highlighting the importance of identifying markers that accurately indicate the risk of acquiring each specific disease entity. Aedes are daytime-biting mosquitoes, while Anopheles preferentially bite during the night. These biting patterns raise the possibility of concurrent exposure to bites from both species. This is important because mosquito saliva, deposited in the skin during blood feeding, induces immune responses that modulate pathogen establishment and infection. Previous studies have focused on characterizing such effects on the vector-pathogen interface for an individual pathogen and its mosquito vector. In this study, we evaluated associations between immune responses to salivary proteins from non-dengue and non-malaria vector mosquito species with clinical characteristics of malaria and dengue, respectively. Surprisingly, antibody responses against Anopheles antigens in dengue patients correlated with red blood cell count and hematocrit, while antibody responses against Aedes proteins were associated with platelet count in malaria patients. Our data indicate that concurrent exposure to multiple disease-carrying mosquito vectors and their salivary proteins with differing immunomodulatory properties could influence the transmission, pathogenesis, and clinical presentation of malaria, dengue fever, and other vector-borne illnesses.

Association of dengue infection with anti-alpha-gal antibodies, IgM, IgG, IgG1, and IgG2.

Dengue virus (DENV) transmitted by the Aedes mosquitoes is the etiological agent of dengue fever, one of the fastest-growing reemerging mosquito-borne diseases on the planet with a 30-fold surge in the last five decades. Interestingly, many arthropod-borne pathogens, including DENV type 2, have been reported to contain an immunogenic glycan galactose-alpha1,3-galactose (alpha-Gal or aGal). The aGal molecule is a common oligosaccharide found in many microorganisms and in most mammals, except for humans and the Old-World primates. The loss of aGal in humans is considered to be an evolutionary innovation for enabling the production of specific antibodies against aGal that could be presented on the glycan of pathogens. The objective of this study was to evaluate different anti-aGal antibodies (IgM, IgG, IgG1, and IgG2) in people exposed to DENV. We observed a significant difference in anti-aGal IgG and IgG1 levels among dengue severity classifications. Furthermore, a significant positive correlation was observed between the anti-aGal IgG and the number of days with dengue symptoms in patients. Additionally, both anti-aGal IgM and IgG levels differ between the two geographical locations of patients. While the anti-aGal IgM and IgG2 levels were not significantly different according to the dengue severity levels, age was negatively correlated with anti-aGal IgM and positively correlated with anti-aGal IgG2. Significant involvement of aGal antibodies in Dengue infection processes is suggested based on the results. Our results open the need for further studies on the exact roles and the mechanisms of the aGal antibodies in Dengue infection.

Dengue and Coronavirus disease (COVID-19) syndemic: Double threat to an overburdened healthcare system in Africa.

Dengue fever (DF) is a significant public health problem in the African continent. The primary prevention strategy against the disease is vaccination and entomological control of vectors; however, implementing such a strategy in several countries in the continent is far below what is necessary to control the disease. The Coronavirus disease (COVID-19) pandemic further aggravated this situation and negatively impacted these measures, mainly the coverage of vaccination campaigns, due to restrictive measures to control the disease. Therefore, the most significant risk is that the incidence of DF in the continent will increase even more in the coming years, as a reflection of the negative impact of the pandemic on the control of the disease. To prevent another public health crisis, immediate and multidisciplinary approaches are required to address the epidemiological control of DF in African countries.

Aedes aegypti anti-salivary proteins IgG levels in a cohort of DENV-like symptoms subjects from a dengue-endemic region in Colombia.

Dengue fever, caused by the dengue virus (DENV), is currently a threat to about half of the world's population. DENV is mainly transmitted to the vertebrate host through the bite of a female Aedes mosquito while taking a blood meal. During this process, salivary proteins are introduced into the host skin and blood to facilitate blood acquisition. These salivary proteins modulate both local (skin) and systemic immune responses. Several salivary proteins have been identified as immunogenic inducing the production of antibodies with some of those proteins also displaying immunomodulatory properties enhancing arboviral infections. IgG antibody responses against salivary gland extracts of a diverse number of mosquitoes, as well as antibody responses against the Ae. aegypti peptide, Nterm-34 kDa, have been suggested as biomarkers of human exposure to mosquito bites while antibodies against AgBR1 and NeSt1 proteins have been investigated for their potential protective effect against Zika virus (ZIKV) and West Nile virus infections. Thus, we were interested in evaluating whether IgG antibodies against AgBR1, NeSt1, Nterm-34 kDa peptide, and SGE were associated with DENV infections and clinical characteristics. For this, we tested samples from volunteers living in a dengue fever endemic area in Colombia in 2019 for the presence of IgG antibodies against those salivary proteins and peptides using an ELISA test. Results from this pilot study suggest an involvement of antibody responses against salivary proteins in dengue disease progression.

Measles outbreak amidst COVID-19 pandemic in Africa: grappling with looming crises.

Coronavirus disease 2019 (COVID-19) and measles are major threats to the health and wellbeing of Africans. Measles is an endemic disease in Africa with a high mortality rate especially in children despite available vaccines. This letter aims to discuss the impact of the COVID-19 pandemic on prevention and management of measles in Africa. The emergence of COVID-19 has exacerbated the morbidities of measles due to multi-factors like the disruption of mass measles routine vaccination, a monopolistic focus on COVID-19 eradication, malnutrition, and poor surveillance. Currently, the COVID-19 pandemic and looming measles epidemic pose a double burden on the African health sector. We recommend urgent interventions from government and other stakeholders including community leaders to strengthen measles research and vaccination programs in Africa amidst the pandemic.

Vertebrate Responses against Arthropod Salivary Proteins and Their Therapeutic Potential.

The saliva of hematophagous arthropods contains a group of active proteins to counteract host responses against injury and to facilitate the success of a bloodmeal. These salivary proteins have significant impacts on modulating pathogen transmission, immunogenicity expression, the establishment of infection, and even disease severity. Recent studies have shown that several salivary proteins are immunogenic and antibodies against them may block infection, thereby suggesting potential vaccine candidates. Here, we discuss the most relevant salivary proteins currently studied for their therapeutic potential as vaccine candidates or to control the transmission of human vector-borne pathogens and immune responses against different arthropod salivary proteins.

Chikungunya Virus Seroprevalence and Associated Factors among Hospital Attendees in Two States of Southwest Nigeria: A Preliminary Assessment.

Chikungunya virus (CHIKV) is a re-emerging pathogen causing long-term polyarthritis and encephalitis. In conducting a preliminary investigation, we hypothesized that there is no serologic evidence of CHIKV infection among attendees of selected hospitals in Lagos and Osun States, Nigeria. Sera from 304 consecutively selected participants were screened for CHIKV IgG and IgM using ELISA. Findings were analyzed vis-à-vis participants' demographic and clinical data. Over 90.0% of the participants had never heard of CHIKV despite the fact that a large proportion of them (88.8%) had secondary/tertiary education. Overall, 41.8% were positive for, at least, one antibody type (IgG or IgM), while about 16.0% of the participants had dual seropositivity (CHIKV IgG and IgM) with gender as associated factor (odds ratio [OR]: 2.8, p = 0.03). Prevalence rates were 31.8% and 38.4% for CHIKV IgG and IgM, respectively. Only hospital location (Osogbo) was associated with CHIKV IgG (OR: 2.2, p = 0.009), while gender alone was associated with CHIKV IgM (OR: 3.0, p = 0.001). Participants seropositive for CHIKV antibodies were mostly adults (18-59 yrs) belonging to the active work-force; five (22.7%) and three (20.0%) of the pregnant participants had CHIKV IgG and IgM, respectively. Detection of CHIKV IgM in some participants might make them potentially infectious to the newborn and mosquito vectors. Importantly, participants positive for either IgG or IgM had fever (72.8%, 67.2%) and general body pains (61.7%, 57.6%), respectively. This ELISA-based study revealed serologic evidence of CHIKV infection among hospital attendees in Lagos and Osun states with the group-specific prevalence rates being considerably high. ABBREVIATIONS: Chikungunya virus (CHIKV); Chikungunya (CHIK); enzyme-linked immunosorbent assay (ELISA); immunoglobulin G or M (IgG/IgM); odds ratio (OR); non-structural proteins (nsP); hemagglutination inhibiting (HI); complement fixing (CF); neutralization test (NT); immunofluorescence assay (IFA); plaque reduction neutralization test (PRNT); confidence interval (CI); analysis of variance (ANOVA); body temperature (BT); Building Nigeria's Response to Climate Change (BNRCC).