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.

Multiple Salivary Proteins from Aedes aegypti Mosquito Bind to the Zika Virus Envelope Protein.

Aedes aegypti mosquitoes are important vectors of several debilitating and deadly arthropod-borne (arbo) viruses, including Yellow Fever virus, Dengue virus, West Nile virus and Zika virus (ZIKV). Arbovirus transmission occurs when an infected mosquito probes the host's skin in search of a blood meal. Salivary proteins from mosquitoes help to acquire blood and have also been shown to enhance pathogen transmission in vivo and in vitro. Here, we evaluated the interaction of mosquito salivary proteins with ZIKV by surface plasmon resonance and enzyme-linked immunosorbent assay. We found that three salivary proteins AAEL000793, AAEL007420, and AAEL006347 bind to the envelope protein of ZIKV with nanomolar affinities. Similar results were obtained using virus-like particles in binding assays. These interactions have no effect on viral replication in cultured endothelial cells and keratinocytes. Additionally, we found detectable antibody levels in ZIKV and DENV serum samples against the recombinant proteins that interact with ZIKV. These results highlight complex interactions between viruses, salivary proteins and antibodies that could be present during viral transmissions.

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.

Laboratory Findings in Patients with Probable Dengue Diagnosis from an Endemic Area in Colombia in 2018.

As demonstrated with the novel coronavirus pandemic, rapid and accurate diagnosis is key to determine the clinical characteristic of a disease and to improve vaccine development. Once the infected person is identified, hematological findings may be used to predict disease outcome and offer the correct treatment. Rapid and accurate diagnosis and clinical parameters are pivotal to track infections during clinical trials and set protection status. This is also applicable for re-emerging diseases like dengue fever, which causes outbreaks in Asia and Latin America every 4 to 5 years. Some areas in the US are also endemic for the transmission of dengue virus (DENV), the causal agent of dengue fever. However, significant number of DENV infections in rural areas are diagnosed solely by clinical and hematological findings because of the lack of availability of ELISA or PCR-based tests or the infrastructure to implement them in the near future. Rapid diagnostic tests (RDT) are a less sensitive, yet they represent a timely way of detecting DENV infections. The purpose of this study was to determine whether there is an association between hematological findings and the probability for an NS1-based DENV RDT to detect the DENV NS1 antigen. We also aimed to describe the hematological parameters that are associated with the diagnosis through each test.

Rol de la homocisteína y vitamina B en el metabolismo óseo / Role of homocysteine and vitamin B in bone metabolism

RESUMEN Se han propuesto varios estudios que sugieren que el grupo de vitaminas B posee un rol en la fisiología ósea. Se realizó una revisión bibliográfica sobre la interacción de este con la homocisteína y la relación de ambos con el metabolismo óseo y la osteoporosis. Algunos estudios han sugerido que los niveles de vitamina B, sobre todo las vitaminas B12 y B9, se han asociado a una baja densitometría ósea y a un aumentado riesgo a fractura, y que estos, a su vez, intervienen en el metabolismo de la homocisteína, por lo que su déficit puede ocasionar un estado de hiperhomocisteinemia. Publicaciones recientes proponen que la hiperhomocisteinemia se encuentra asociada a desmineralización ósea, baja calidad de masa ósea y aumento de biomarcadores de recambio óseo, dado que influye en la actividad osteoclástica y en los enlaces cruzados de colágeno. Por lo tanto, la hiperhomocisteinemia puede ser un factor que reduce la densidad y la calidad ósea. Se necesita más información para determinar el papel que tiene cada vitamina directamente en la salud ósea, o si estas solo influyen a través de las concentraciones séricas de homocisteína.

ABSTRACT Several studies have suggested a role for B-vitamins in bone physiology. A systematic review is presented on the interaction of B-vitamins with homocysteine and the relationship of both in bone metabolism and osteoporosis. The levels of vitamin-B, particularly B12 and B9, have been associated with a low bone mineral density and an increased risk of fracture. At the same time, its deficit affects the metabolism of homocysteine, which can then result in a high serum homocysteine. Recent findings have proposed that high serum homocysteine is linked to bone demineralisation, low quality of bone mass, and an increase in bone turnover biomarkers, given the influence over the osteoclastic activity and the cross-linking of collagen molecules. Therefore, high serum homocysteine could be a factor that reduces bone density and quality. More information is needed to determine whether there is a direct role of each vitamin in bone health, or if they are just influenced by homocysteine serum concentrations.

Quality of life in Ecuadorian patients with established rheumatoid arthritis.

PURPOSE: To evaluate quality of life in patients with established rheumatoid arthritis (RA) and identify the factors that negatively affect it. METHODS: This was a cross-sectional study with patients with established RA from a rheumatology center in Ecuador. The RA Quality of Life (RAQoL) questionnaire was used to assess QoL and the Health Assessment Questionnaire - disability index (HAQ-DI) questionnaire for functional capacity. In addition, demographics, clinical characteristics, and markers of disease activity were included. Data were analyzed using SPSS 22. RESULTS: Of 186 patients, 89.8% were women, with a mean age of 51 years, 86.6% had symmetrical polyarticular involvement, 40.3% erosions, 46.8% morning stiffness, 46.8% xerophthalmia, and 39.2% fatigue. Depression was the most frequent comorbidity - 42.5%. The mean HAQ-DI score was 0.8, and 26.9% had functional disability. The mean RAQoL score was 7.2. Xerophthalmia, xerostomia, fatigue, morning stiffness, and depression were related to higher scores in the RAQoL (p<0.05). The mean RAQoL was higher in patients with more disease activity and comorbidities (p<0.05). Likewise, patients with functional disability had a mean RAQoL score of 15.6 versus 4.1 in patients without disability (p<0.05). There were positive correlations between RAQoL and ESR, CRP, painful-joint count, swollen-joint count, VAS of pain, and physician assessment (p<0.05). CONCLUSION: QoL is severely affected in patients with RA. Depression, fatigue, morning stiffness, pain, high disease activity, and disability have a negative effect on QoL in RA. Likewise, patients with more comorbidities and extraarticular manifestations show worse QoL.

Systematic reviews in orthodontics: Impact of the PRISMA for Abstracts checklist on completeness of reporting.

INTRODUCTION: This study evaluated and compared the completeness of reporting of abstracts of orthodontics systematic reviews before and after the publication of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for Abstracts Checklist (PRISMA-A). METHODS: Abstracts of systematic reviews and meta-analyses in orthodontics published in PubMed, Latin American and Caribbean Health Sciences Literature, and the Cochrane Database of Systematic Reviews databases before March 23, 2018, that met the predefined inclusion and exclusion criteria, were evaluated using the 12 items of PRISMA-A, scoring each item from 0 to 2. Abstracts were classified into 2 groups: before and after publication of the PRISMA-A checklist. Three calibrated evaluators (intraclass correlation coefficient and kappa > 0.8) assessed the scores for compliance with the checklist. The number of authors, country of affiliation of the first author, performance of meta-analysis, and topic of the article were recorded. A regression analysis was performed to assess the associations between abstract characteristics and the PRISMA-A scores. RESULTS: Of 1034 abstracts evaluated, 389 were included in the analysis. The mean PRISMA-A score was 53.39 (95% CI, 51.83-54.96). The overall score for studies published after the publication of the checklist was significantly higher than for studies published before (P ≤ 0.0001). The components returning significantly higher scores after publication of PRISMA-A were title (P = 0.024), information from databases (P = 0.026), risk of bias (P ≤ 0.0001), included studies (P ≤ 0.0001), synthesis of results (P ≤ 0.0001), interpretation of results (P = 0.035), financing and conflict of interest (P ≤ 0.0001), and registration (P ≤ 0.0001). These results showed the positive effect of PRISMA-A had on the quality of reporting of orthodontics systematic reviews. Nevertheless, the poor adherence revealed that there is still need for improvement in the quality of abstract reporting. CONCLUSIONS: The quality of reporting of abstracts of orthodontic systematic reviews and meta-analyses increased after the introduction of PRISMA-A.

IgG1 and IgG4 antibodies against Aedes aegypti salivary proteins and risk for dengue infections.

Dengue virus (DENV) is an arbovirus responsible for a significant number of deaths in Latin America. This virus is transmitted through the bite of Aedes aegypti, the main mosquito vector, and Ae. albopictus. During blood uptake, the mosquito injects its saliva into the host to facilitate the feeding process. Mosquito saliva contains potent immunogens capable of inducing antibody production directly related to mosquito bite exposure intensity and disease risk. In this study, we first determined the DENV infection status by two different DENV non-structural protein 1 (NS1) based rapid tests and qRT-PCR, then measured the levels of IgG1 and IgG4 antibodies against salivary proteins of Ae. aegypti female mosquitoes in volunteers living in a dengue endemic area. Our results show that people with a positive DENV diagnosis present higher levels of IgG4 antibodies than people with a negative diagnostic test, and that these antibody levels were higher in people with secondary DENV infections. With this study, we show that detection of IgG4 antibodies against mosquito saliva may be a reliable method to evaluate the risk of dengue infection.

A relevant in vitro human model for the study of Zika virus antibody-dependent enhancement.

Zika virus (ZIKV) is a mosquito-borne flavivirus that has recently been responsible for a serious outbreak of disease in South and Central America. Infection with ZIKV has been associated with severe neurological symptoms and the development of microcephaly in unborn fetuses. Many of the regions involved in the current outbreak are known to be endemic for another flavivirus, dengue virus (DENV), which indicates that a large percentage of the population may have pre-existing DENV immunity. Thus, it is vital to investigate what impact pre-existing DENV immunity has on ZIKV infection. Here, we use primary human myeloid cells as a model for ZIKV enhancement in the presence of DENV antibodies. We show that sera containing DENV antibodies from individuals living in a DENV-endemic area are able to enhance ZIKV infection in a human macrophage-derived cell line and primary human macrophages. We also demonstrate altered pro-inflammatory cytokine production in macrophages with enhanced ZIKV infection. Our study indicates an important role for pre-existing DENV immunity on ZIKV infection in primary human immune cells and establishes a relevant in vitro model to study ZIKV antibody-dependent enhancement.

Natural Mosquito-Pathogen Hybrid IgG4 Antibodies in Vector-Borne Diseases: A Hypothesis.

Chronic exposure to antigens may favor the production of IgG4 antibodies over other antibody types. Recent studies have shown that up to a 30% of normal human IgG4 is bi-specific and is able to recognize two antigens of different nature. A requirement for this specificity is the presence of both eliciting antigens in the same time and at the same place where the immune response is induced. During transmission of most vector-borne diseases, the pathogen is delivered to the vertebrate host along with the arthropod saliva during blood feeding and previous studies have shown the existence of IgG4 antibodies against mosquito salivary allergens. However, there is very little ongoing research or information available regarding IgG4 bi-specificity with regard to infectious disease, particularly during immune responses to vector-borne diseases, such as malaria, filariasis, or dengue virus infection. Here, we provide background information and present our hypothesis that IgG4 may not only be a useful tool to measure exposure to infected mosquito bites, but that these bi-specific antibodies may also play an important role in modulation of the immune response against malaria and other vector-borne diseases in endemic settings.

Human C5a Protein Participates in the Mosquito Immune Response Against Dengue Virus.

Dengue virus (DENV) is transmitted by Aedes spp mosquitoes during a bloodmeal uptake. The bloodmeal consists of host cells, immune factors, and possibly blood-borne pathogens, such as arboviruses. Human cells and immune-related factors, like the complement system, can remain active in the bloodmeal and may be able to interact with pathogens in the mosquito. Previous studies have shown that active complement proteins impact Plasmodium parasite viability in the Anopheles midgut. Thus, we investigated the effects of the human complement on DENV infection in the midgut of Aedes aegypti. Our findings indicate that mosquitoes receiving DENV mixed with normal non-inactivated human serum showed significantly lower viremia than those fed with heat-inactivated serum. This implies that human complement may act to limit DENV infection in the mosquito midgut. In addition, we found that human complement C5a protein was able to directly communicate with mosquito cells, affecting the cell antiviral response against DENV. Our results also show that human C5a protein is able to interact with several membrane-bound mosquito proteins. Together these results suggest an important role of human complement protein in DENV transmission.

An. gambiae gSG6-P1 evaluation as a proxy for human-vector contact in the Americas: a pilot study.

BACKGROUND: During blood meal, the female mosquito injects saliva able to elicit an immune response in the vertebrate. This immune response has been proven to reflect the intensity of exposure to mosquito bites and risk of infection for vector transmitted pathogens such as malaria. The peptide gSG6-P1 of An. gambiae saliva has been demonstrated to be antigenic and highly specific to Anopheles as a genus. However, the applicability of gSG6-P1 to measure exposure to different Anopheles species endemic in the Americas has yet to be evaluated. The purpose of this pilot study was to test whether human participants living in American countries present antibodies able to recognize the gSG6-P1, and whether these antibodies are useful as a proxy for mosquito bite exposure and malaria risk. METHODS: We tested human serum samples from Colombia, Chile, and the United States for the presence of IgG antibodies against gSG6-P1 by ELISA. Antibody concentrations were expressed as delta optical density (ΔOD) of each sera tested in duplicates. The difference in the antibody concentrations between groups was tested using the nonparametric Mann Whitney test (independent groups) and the nonparametric Wilcoxon matched-pairs signed rank test (dependent groups). All differences were considered significant with a P < 0.05. RESULTS: We found that the concentration of gSG6-P1 antibodies was significantly correlated with malaria infection status and mosquito bite exposure history. People with clinical malaria presented significantly higher concentrations of IgG anti-gSG6-P1 antibodies than healthy controls. Additionally, a significant raise in antibody concentrations was observed in subjects returning from malaria endemic areas. CONCLUSION: Our data shows that gSG6-P1 is a suitable candidate for the evaluation of exposure to Anopheles mosquito bites, risk of malaria transmission, and effectiveness of protection measures against mosquito bites in the Americas.

Evaluation of clinical rules in a standalone pharmacy based clinical decision support system for hospitalized and nursing home patients.

OBJECTIVES: To improve the current standalone pharmacy clinical decision support system (CDSS) by identifying and quantifying the benefits and limitations of the system. METHODS: Alerts and handling of the executed clinical rules were extracted from the CDSS from the period September 2011 to December 2011. The number of executed clinical rule alerts, number of actions on alerts, and the reason why alerts were classified as not relevant were analyzed. The alerts where considered clinically relevant when the pharmacist needed to contact the physician. RESULTS: The 4065 alerts have been separated into: 1137 (28.0%) new alerts, 2797 (68.8%) repeat alerts and 131 (3.2%) double alerts. When the alerts were analyzed, only 3.6% were considered clinically relevant. Reasons why alerts were considered as not to be relevant were: (a) the dosage was correct or already adjusted, (b) the drug was (temporarily) stopped and (c) the monitored laboratory value or drug dosage had already reverted to be within the reference limits. The reasons for no action were linked to three categorical limitations of the used system: 'algorithm alert criteria', 'CDSS optimization', and 'data delivery'. CONCLUSION: This study highlighted a number of ways in which the CDSS could be improved. These different aspects have been identified as important for developing an efficient CDSS.

Aedes aegypti anti-salivary gland antibody concentration and dengue virus exposure history in healthy individuals living in an endemic area in Colombia.

INTRODUCTION: Mosquito salivary proteins are able to induce an antibody response that reflects the level of human-vector contact. IgG antibodies against dengue virus (DENV-IgG) are indicators of previous exposure. The risk of DENV transmission is not only associated to mosquito or dengue factors, but also to socioeconomic factors that may play an important role in the disease epidemiology. OBJECTIVE: To determine the effect of the presence of Aedes aegypti mosquitos in different stages in households and the history of dengue exposure on vector-human contact determined by the level of anti-salivary protein antibodies in people living in a Colombian endemic area. MATERIALS AND METHODS: A pilot study of 58 households and 55 human subjects was conducted in Norte de Santander, Colombia. A questionnaire for socioeconomic factors was administered and houses were examined for the presence of Ae. aegypti specimens in the aquatic stages. The level of DENV-IgG antibodies (DENV-IgG), in addition to IgG and IgM anti- Ae. aegypti salivary gland extract (SGE) antibodies (SGE-IgG, SGE-IgM) were evaluated by ELISA using blood collected in filter paper. RESULTS: We found a significant higher level of SGE-IgG antibodies in subjects living in houses with Ae. aegypti in aquatic stages. We also found a higher concentration of SGE-IgG antibodies in people exposed to DENV, a positive correlation between IgM-SGE and IgG-DENV and a negative correlation with IgG-SGE. CONCLUSION: Anti-salivary proteins antibodies are consistent with the presence of Ae. aegypti aquatic stages inside houses and DENV-IgG antibodies concentrations.

Use of anti-Aedes aegypti salivary extract antibody concentration to correlate risk of vector exposure and dengue transmission risk in Colombia.

Norte de Santander is a region in Colombia with a high incidence of dengue virus (DENV). In this study, we examined the serum concentration of anti-Aedes salivary gland extract (SGE) antibodies as a biomarker of DENV infection and transmission, and assessed the duration of anti-SGE antibody concentration after exposure to the vector ceased. We also determined whether SGE antibody concentration could differentiate between positive and negative DENV infected individuals and whether there are differences in exposure for each DENV serotype. We observed a significant decrease in the concentration of IgG antibodies at least 40 days after returning to an "Ae. aegypti-free" area. In addition, we found significantly higher anti-SGE IgG concentrations in DENV positive patients with some difference in exposure to mosquito bites among DENV serotypes. We conclude that the concentration of IgG antibodies against SGE is an accurate indicator of risk of dengue virus transmission and disease presence.

Hipotiroidismo y riesgo de aborto / Hypothyroidism and risk of miscarriage

Objetivo: revisar, en la literatura disponible, aquellas evidencias que muestren la asociación entre hipotiroidismo y aborto. Metodología: se realizó una búsqueda bibliográfica utilizando la base de datos especializada Medline y los buscadores Pubmed y Ovid para identificar literatura relevante. Resultados: aunque varios estudios mostraron un aumento en el riesgo de aborto en las pacientes con hipotiroidismo clínico, hipotiroidismo subclínico y en pacientes eutiroideas con anticuerpos antitiroideos, fue en este último grupo de mujeres en donde se evidenció una fuerte asociación entre el hipotiroidismo y el aborto. Por lo tanto, se recomienda realizar el diagnóstico y tratamiento temprano del hipotiroidismo clínico y subclínico en las mujeres embarazadas, así como la búsqueda de anticuerpos antitiroideos en el grupo de abortadoras recurrentes; y aunque algunos trabajos han demostrado una disminución en el riesgo de aborto utilizando suplencia con levotiroxina en las pacientes con anticuerpos antitiroideos, aún no se puede recomendar dicha terapia en este grupo de pacientes. Conclusión: se requieren estudios adicionales con un mayor número de pacientes y un adecuado diseño para definir claramente la asociación entre aborto y enfermedad tiroidea, y así poder establecer terapias adecuadas.

Objective: this article was aimed at searching the literature for an association between hypothyroidism and miscarriage. Methodology: a search was made on the Medline electronic database, using Pubmed and Ovid for identifying relevant material. Results: some studies showed an increased risk of miscarriage in patients suffering from overt hypothyroidism and subclinical hypothyroidism, and in euthyroid patients having antithyroid antibodies; a strong association was seen in the latter group. Early diagnosis and treatment of pregnant women having subclinical, overt hypothyroidism and the search for antithyroid antibodies is highly recommended in recurrent miscarriage. Despite some studies having shown a decrease in the risk of miscarriage when levothyroxine treatment was used with patients having antithyroid antibodies, it cannot be recommended yet. Conclusion: more studies using an increased number of patients have to be carried out to define a true association between miscarriage and thyroid disorders and thus establish suitable treatment.