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Detection of Zika virus in saliva
... CDC Emergency Operations Center also declared actions for moves to the highest level of activation on February 3, 2016 [12] . ZIKV has been detected in semen, blood and other body fluids and especially stays longer time in semen [13][14][15] . The two main routes of ZIKV transmission are mosquito bites and sexual contacts. ...
... ZIKV can exist in semen much longer than in blood and other body fluids [13][14][15] . It means that sexual transmission has a longer infectious duration than mosquito-human transmission. ...
... Obviously, F V −1 in Eq. (14) and F * 11 in Eq. (15) have the same leading eigenvalue. Additionally, since F * 11 is non negative, according to the Perron-Frobenius theorem it has a single, unique eigenvalue as the basic reproduction number denoted by R 0 which is positive, real, and strictly greater than all the others. ...
The impact of Zika virus (ZIKV) is a global public health issue and its severity is ongoing. It is primarily transmitted via mosquitoes and sexual contacts. Sexual transmission experiences a longer period and strongly depends on the topological structure of sexual networks. However, relatively little work has been done to explore the characteristics of ZIKV infection in sexual networks, and further control ZIKV by changing contact patterns between individuals. In this paper, using the settings of Costa Rica as a case study, we developed a heterosexual network-based model, to study the effect of changing the degree heterogeneity by the measure of deleting the sexual contacts of individuals with small number but large degree in the sexually active places at different time, on ZIKV spread. We obtained a threshold time, which is later than the peak time of ZIKV infected cases. If applied prior to the threshold time, the measure will inhibit ZIKV infection and lower the final size; surprisingly if past the threshold time, the measure will boost ZIKV infection and increase the final size. In addition, our model yielded higher cumulative infection among females, which is in line with observations. Our results provide some guidelines for preventing and controlling mosquito-human and sexual transmissions against ZIKV, particularly for countries with a high rate of sexually transmitted infections.
... CDC Emergency Operations Center also declared actions for moves to the highest level of activation on February 3, 2016 [12] . ZIKV has been detected in semen, blood and other body fluids and especially stays longer time in semen [13][14][15] . The two main routes of ZIKV transmission are mosquito bites and sexual contacts. ...
... ZIKV can exist in semen much longer than in blood and other body fluids [13][14][15] . It means that sexual transmission has a longer infectious duration than mosquito-human transmission. ...
... Obviously, F V −1 in Eq. (14) and F * 11 in Eq. (15) have the same leading eigenvalue. Additionally, since F * 11 is non negative, according to the Perron-Frobenius theorem it has a single, unique eigenvalue as the basic reproduction number denoted by R 0 which is positive, real, and strictly greater than all the others. ...
... In both humans and macaques, ZIKV can be detected in the blood for short periods after symptom onset (17)(18)(19)(20). Infectious virus is also readily shed in the saliva (19) and urine (20,21), in semen for protracted periods (22,23), and in high amounts in the central nervous system, including cerebrospinal fluid (CSF) (11). ...
... In both humans and macaques, ZIKV can be detected in the blood for short periods after symptom onset (17)(18)(19)(20). Infectious virus is also readily shed in the saliva (19) and urine (20,21), in semen for protracted periods (22,23), and in high amounts in the central nervous system, including cerebrospinal fluid (CSF) (11). At present, no licensed preventative drug or treatment is available for established ZIKV infection. ...
Zika virus infection in humans has been associated with serious reproductive and neurological complications. At present, no protective antiviral drug treatment is available. Here, we describe the testing and evaluation of the antiviral drug, galidesivir, against Zika virus infection in rhesus macaques. We conducted four preclinical studies in rhesus macaques to assess the safety, antiviral efficacy, and dosing strategies for galidesivir (BCX4430) against Zika virus infection. We treated 70 rhesus macaques infected by various routes with the Puerto Rico or Thai Zika virus isolates. We evaluated galidesivir administered as early as 90 min and as late as 72 hours after subcutaneous Zika virus infection and as late as 5 days after intravaginal infection. We evaluated the efficacy of a range of galidesivir doses with endpoints including Zika virus RNA in plasma, saliva, urine, and cerebrospinal fluid. Galidesivir dosing in rhesus macaques was safe and offered postexposure protection against Zika virus infection. Galidesivir exhibited favorable pharmacokinetics with no observed teratogenic effects in rats or rabbits at any dose tested. The antiviral efficacy of galidesivir observed in the blood and central nervous system of infected animals warrants continued evaluation of this compound for the treatment of flaviviral infections.
... ZIKV can be detected in urine [63] and saliva [64]. Although, as discussed further, the method of choice for diagnosis is the RT-PCR in blood, diagnosis in saliva is also possible and can be useful when blood sampling is challenging [64]. ...
... ZIKV can be detected in urine [63] and saliva [64]. Although, as discussed further, the method of choice for diagnosis is the RT-PCR in blood, diagnosis in saliva is also possible and can be useful when blood sampling is challenging [64]. Interhuman transmission however has only been suspected once. ...
Zika virus (ZIKV), a neurotropic single-stranded RNA flavivirus, remains an important cause of congenital infection, fetal microcephaly, and Guillain-Barré syndrome in populations where ZIKV has adapted to a nexus involving the Aedes mosquitoes and humans. To date, outbreaks of ZIKV have occurred in Africa, Southeast Asia, the Pacific islands, the Americas, and the Caribbean. Emerging evidence, however, suggests that the virus also has the potential to cause infections in Europe, where autochtonous transmission of the virus has been identified. This review focuses on evolving ZIKV epidemiology, modes of transmission and host-virus interactions. The clinical manifestations, diagnostic issues relating to cross-reactivity to the dengue flavivirus and concerns surrounding ZIKV infection in pregnancy are discussed. In the last section, current challenges in treatment and prevention are outlined.
... Moreover, studies having compared the use of venous and capillary blood samples for the diagnosis of DENV and ZIKV infections showed that the duration of virus detection was longer in capillary blood [22,23]. As an alternative to blood collection, saliva sampling is non-invasive and was shown to be suitable for the detection of arboviruses such as DENV, ZIKV, and CHIKV [24][25][26][27]. In addition to the surveillance of arboviruses, saliva could be used to detect respiratory viruses such as influenza virus [28], which regularly causes epidemics in French Polynesia [29]. ...
In French Polynesia, following the emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in March 2020, several control measures were implemented to prevent virus spread, including a population lockdown and the interruption of international air traffic. SARS-CoV-2 local transmission rapidly stopped, and circulation of dengue virus serotypes 1 and 2, the only arboviruses being detected at that time, decreased. After the borders re-opened, a surveillance strategy consisting of the testing by SARS-CoV-2 RT-PCR of travelers entering French Polynesia, and isolating those with ongoing infection, was implemented. This strategy proved efficient to limit the introduction of SARS-CoV-2, and should be considered to prevent the importation of other pathogens, including mosquito-borne viruses, in geographically isolated areas such as French Polynesia.
... When ZIKV opportunistically enters the human transmission cycle from the sylvatic cycle, the virus may initiate epidemics in humans. In addition to the Aedes-human transmission cycle, non-vectored transmission between humans has been hypothesized because the ZIKV genome can be found in saliva (Musso et al., 2015), urine (Gourinat et al., 2015), and even tears (Miner et al., 2016). ...
Mosquito-borne Zika virus (ZIKV) was considered an obscure virus causing only mild or self-limited symptoms until the explosive outbreaks in French Polynesia in 2013–2014 and in the Americas in 2015–2016, resulting in more than 700,000 cases of the disease, with occasional miscarriage and severe congenital birth defects, such as intrauterine growth restriction, fetal microcephaly, and other neurodevelopmental malformations. In this review, we summarized the evolution of ZIKV from a mundane virus to an epidemic virus. ZIKV has acquired a panel of amino acid substitutions during evolution when the virus spread from Africa, Asia, Pacific, through to the Americas. Robust occurrence of mutations in the evolution of ZIKV has increased its epidemic potential. Here we discussed the contributions of these evolutionary mutations to the enhancement of viral pathogenicity and host-mosquito transmission. We further explored the potential hypotheses for the increase in ZIKV activity in recent decades. Through this review, we also explored the hypotheses for the occurrence of the recent ZIKV epidemics and highlighted the potential roles of various factors including pathogen-, host-, vector-related, and environmental factors, which may have synergistically contributed to the ZIKV epidemics.
... The Zika virus has also been reported to be present in amniotic fluid, 20 urine, 21 saliva, 22 breast milk 23 and semen 24,25 of infected individuals, thereby making transmission via other routes possible. However, we observed that only 5% of the study participants knew that ZVD could be transmitted through mosquito bites as well as sexual intercourse with infected persons. ...
Background: Nigeria is not insulated from the global threat of Zika virus disease (ZVD) because of international travel and the presence of Zika-virus-carrying mosquitoes in the country. A paucity of studies exists concerning knowledge of ZVD among atrisk populations. Thus, the necessity for assessment of knowledge of ZVD among reproductive-age women in general outpatient setting. Materials and methods: A cross-sectional study was conducted on 377 reproductive-age women attending a Nigerian tertiary hospital’s general outpatient clinic. Their knowledge of ZVD was assessed using a structured questionnaire. A chi-square test was used to assess the relationship between participants’ sociodemographics and ZVD knowledge. Results: The participants’ median age was 27.0 ± 7.19 years. Though 68.97% of participants were aware of ZVD, only 23.85% of those had good knowledge of ZVD. Their median knowledge score was 57.14%. Participants’ age (< 27 years) (p = 0.00399), tribe (Hausa) (p = 0.0174) and monogamous family type (p = 0.0108) were associated with good knowledge of ZVD. Only 5% knew that ZVD is transmitted through both mosquito bites and a sexual route. Some 80% were unaware that everybody was at risk of ZVD but 80.77% knew it could cause microcephaly. Insecticide-treated nets (80.77%), environmental sanitation (78.08%) and indoor insecticide spraying (58.85%) were preventive measures reported by most participants; a minority reported mosquito repellents (28.46%), wearing of protective clothing (36.15%), and traditional medicines (20.00%) as preventive measures. They lacked knowledge of prevention of sexual transmission. Conclusion: Participants’ knowledge of ZVD was inadequate despite the high awareness rate. Stakeholders may need to address existing knowledge gaps through effective public enlightenment. (Full text of the research articles are available online at www.medpharm.tandfonline.com/ojfp) S Afr Fam Pract 2017; DOI: 10.1080/20786190.2017.1313484
... The Zika virus (ZIKV) has been found in body fluids such as blood, urine, semen, brain and spinal fluids, saliva, rectal swab, vaginal secretions, amniotic fluid, and breast milk [1][2][3][4][5][6][7][8]. Studies have found that the ZIKV RNA can persist longer in urine and semen when compared to its presence in blood [5,7,9]. ...
Zika virus (ZIKV) has been detected in blood, urine, semen, cerebral spinal fluid, saliva, amniotic fluid, and breast milk. In most ZIKV infected individuals, the virus is detected in the blood to one week after the onset of symptoms and has been found to persist longer in urine and semen. To better understand virus dynamics, a prospective cohort study was conducted in Brazil to assess the presence and duration of ZIKV and related markers (viral RNA, antibodies, T cell response, and innate immunity) in blood, semen, saliva, urine, vaginal secretions/menstrual blood, rectal swab and sweat. The objective of the current manuscript is to describe the cohort, including an overview of the collected data and a description of the baseline characteristics of the participants. Men and women ≥ 18 years with acute illness and their symptomatic and asymptomatic household contacts with positive reverse transcriptase-polymerase chain reaction test for ZIKV in blood and/or urine were included. All participants were followed up for 12 months. From July 2017 to June 2019, a total of 786 participants (284 men, 502 women) were screened. Of these, 260 (33.1%) were enrolled in the study; index cases: 64 men (24.6%), 162 (62.3%) women; household contacts: 12 men (4.6%), 22 (8.5%) women. There was a statistically significant difference in age and sex between enrolled and not enrolled participants (p
... Furthermore, ZIKV is linked to microcephaly in newborns with infected mothers and Guillain-Barré syndrome, which means that early detection is critical [109][110][111]. Currently, the most common diagnostic method is RT-PCR, which can detect ZIKV genome in biofluid samples, such as saliva, human serum, or urine [112][113][114][115]. However, this method requires trained personnel and expensive equipment, and it is time-consuming to perform, as mentioned before. ...
The last few decades have been plagued by viral outbreaks that present some of the biggest challenges to public safety. The current coronavirus (COVID-19) disease pandemic has exponentiated these concerns. Increased research on diagnostic tools is currently being implemented in order to assist with rapid identification of the virus, as mass diagnosis and containment is the best way to prevent the outbreak of the virus. Accordingly, there is a growing urgency to establish a point-of-care device for the rapid detection of coronavirus to prevent subsequent spread. This device needs to be sensitive, selective, and exhibit rapid diagnostic capabilities. Electrochemical biosensors have demonstrated these traits and, hence, serve as promising candidates for the detection of viruses. This review summarizes the designs and features of electrochemical biosensors developed for some past and current pandemic or epidemic viruses, including influenza, HIV, Ebola, and Zika. Alongside the design, this review also discusses the detection principles, fabrication techniques, and applications of the biosensors. Finally, research and perspective of biosensors as potential detection tools for the rapid identification of SARS-CoV-2 is discussed.
... However, the time window for detection of viral RNA is short and the average level of viral RNA is low [22][23][24], leading to limited sensitivity of the standard PCR assays [25]. Moreover, the sensitivity of detection varies not only according to the sample type [26][27][28][29][30][31][32], but is also subject to variation in diagnostic performance between laboratories in outbreak afflicted areas [33]. Given that most patients only experience mild symptoms or in up to 80% of cases, an asymptomatic infection [3], viral RNA is often undetectable by the time a patient seeks medical care. ...
Background
Serological diagnosis of Zika virus (ZIKV) infection is challenging because of the antibody cross-reactivity among flaviviruses. At the same time, the role of Nucleic Acid Testing (NAT) is limited by the low proportion of symptomatic infections and the low average viral load. Here, we compared the diagnostic performance of commercially available IgM, IgAM, and IgG ELISAs in sequential samples during the ZIKV and chikungunya (CHIKV) epidemics and co-circulation of dengue virus (DENV) in Brazil and Venezuela.
Methodology/Principal findings
Acute (day of illness 1–5) and follow-up (day of illness ≥ 6) blood samples were collected from nine hundred and seven symptomatic patients enrolled in a prospective multicenter study of symptomatic patients recruited between June 2012 and August 2016. Acute samples were tested by RT-PCR for ZIKV, DENV, and CHIKV. Acute and follow-up samples were tested for IgM, IgAM, and IgG antibodies to ZIKV using commercially available ELISAs. Among follow-up samples with a RT-PCR confirmed ZIKV infection, anti-ZIKV IgAM sensitivity was 93.5% (43/48), while IgM and IgG exhibited sensitivities of 30.3% (10/35) and 72% (18/25), respectively. An additional 24% (26/109) of ZIKV infections were detected via IgAM seroconversion in ZIKV/DENV/CHIKV RT-PCR negative patients. The specificity of anti-ZIKV IgM was estimated at 93% and that of IgAM at 85%.
Conclusions/Significance
Our findings exemplify the challenges of the assessment of test performance for ZIKV serological tests in the real-world setting, during co-circulation of DENV, ZIKV, and CHIKV. However, we can also demonstrate that the IgAM immunoassay exhibits superior sensitivity to detect ZIKV RT-PCR confirmed infections compared to IgG and IgM immunoassays. The IgAM assay also proves to be promising for detection of anti-ZIKV seroconversions in sequential samples, both in ZIKV PCR-positive as well as PCR-negative patients, making this a candidate assay for serological monitoring of pregnant women in future ZIKV outbreaks.
... The assessment of serial breast milk samples from women with ZIKV virus and consistent reporting of the methods for obtaining and processing breast milk samples will be critical to understanding viral dynamics in breast milk and the potential of viral transmission. Additionally, as ZIKV RNA has been detected in the skin [47], saliva [48], and conjunctival fluids [49,50], suggesting potential transmission routes due to increased contact between mother and the child while caring and breastfeeding, it is important to consider the assessment of these bodily fluids when evaluating the risk of mother-to-child transmission of ZIKV through breastfeeding. ...
We systematically searched regional and international databases and screened 1658 non- duplicate records describing women with suspected or confirmed ZIKV infection, intending to breastfeed or give breast milk to an infant to examine the potential of mother-to-child transmission of Zika virus (ZIKV) through breast milk or breastfeeding-related practices. Fourteen studies met our inclusion criteria and inform this analysis. These studies reported on 97 mother–children pairs who provided breast milk for ZIKV assessment. Seventeen breast milk samples from different women were found positive for ZIKV via RT-PCR, and ZIKV replication was found in cell cultures from five out of seven breast milk samples from different women. Only three out of six infants who had ZIKV infection were breastfed, no evidence of clinical complications was found to be associated with ZIKV RNA in breast milk. This review updates our previous report by including 12 new articles, in which we found no evidence of ZIKV mother-to-child transmission through breast milk intake or breastfeeding. As the certainty of the present evidence is low, additional studies are still warranted to determine if ZIKV can be transmitted through breastfeeding.
... Zika virus RNA was detected in saliva significantly more frequently as compared with serum of 182 patients in French Polynesia (35 vs 16; 19.2% vs 8.8%), although there was no significant difference in the duration of positivity between the 2 samples. 38 Bonaldo et al demonstrated the presence of viable (infectious) ZIKV in the saliva of Brazilian patients, up to the titer of 80 plaqueforming units per mL. 35 Although saliva functions as a protective barrier for virus entry, 39 a break in the epithelial lining of the oral mucosa or gingival disease may facilitate virus entry into blood. ...
Since its first outbreak in 2007 in the Pacific (Yap islands and Federal States of Micronesia), Zika virus has gradually and recently spread to the Americas in 2015. The neurotropic character of the virus was first noted during this outbreak in Brazil in 2015. Increasing number of infants born with microcephaly and other congenital deformities were identified through studies that have highlighted the importance of prevention of transmission of Zika virus in pregnant women. Long-term outcomes in infants born with this infection are now better understood than at the time of onset of this outbreak. Topics covered in this review include the history, modes of transmission, diagnosis of suspected cases, pathophysiology, complications, and prevention of Zika virus infection.
... Nucleic acids are among the most important biomarkers of disease, and a large variety of diagnostic nucleic acid tests (NATs) have been developed to detect their presence in diagnostic settings, including polymerase chain reaction (PCR), loop-mediated isothermal amplification (LAMP), and rolling circle amplification [1][2][3][4]. Although very powerful, these tests rely on the use of enzymes, which poses several challenges for use at the point of care or in low-resource settings. ...
Among nucleic acid diagnostic strategies, non-enzymatic tests are the most promising for application at the point of care in low-resource settings. They remain relatively under-utilized, however, due to inadequate sensitivity. Inspired by a recent demonstration of a highly-sensitive dumbbell DNA amplification strategy, we developed an automated, self-contained assay for detection of target DNA. In this new diagnostic platform, called the automated Pi-powered looping oligonucleotide transporter, magnetic beads capture the target DNA and are then loaded into a microfluidic reaction cassette along with the other reaction solutions. A stepper motor controls the motion of the cassette relative to an external magnetic field, which moves the magnetic beads through the reaction solutions automatically. Real-time fluorescence is used to measure the accumulation of dumbbells on the magnetic bead surface. Left-handed DNA dumbbells produce a distinct signal which reflects the level of non-specific amplification, acting as an internal control. The autoPiLOT assay detected as little as 5 fM target DNA, and was also successfully applied to the detection of S. mansoni DNA. The autoPiLOT design is a novel step forward in the development of a sensitive, user-friendly, low-resource, non-enzymatic diagnostic test.
... ZIKV is transmitted by mosquitoes of the genus Aedes and, unlike other FV, there is evidence for sexual and vertical transmission as well (Musso et al., 2015;Hamel et al., 2016;Miner et al., 2016;Musso & Gubler, 2016). Moreover, the presence of ZIKV was determined in different human fluids and tissues as semen, saliva, tears, urine, eyes, brain, testes, and female genital tract (Miner & Diamond, 2017;Paz Bailery et al., 2018). ...
Zika Virus (ZIKV) is an RNA virus that belongs to the Flavivirus (FV) genus. In the last years, several unique characteristics of ZIKV among FV have been revealed, as the multiple routes of transmission and its ability to reach different human tissues, including the central nervous system. Thus, one of the most intriguing features of ZIKV biology is its ability to cross diverse complex biological barriers. The main aim of this study is to contribute to the understanding of the still unclear mechanisms behind this viral activity. We investigated an African strain and two South American ZIKV isolates belonging to the Asian lineage, in order to characterize possible differences regarding their ability to disturb intercellular junctions. The Asian isolates correspond to an imported (Venezuelan) and an autochthonous (Argentinian) ZIKV strain for which there is still no data available. We focused on occludin and DLG1 expression as markers of tight and adherent junctions, respectively. For this, we applied a quantitative immunofluorescence assay that can ascertain alterations in the cell junction proteins expression in the infected cells. Our findings indicated that the different ZIKV strains were able to reduce the levels of both polarity proteins without altering their overall cell distribution. Moreover, the grade of this effect was strain-dependent, being the DLG1 reduction higher for the African and Asian Venezuelan isolates and, on the contrary, occludin down-regulation was more noticeable for the Argentinian strain. Interestingly, among both junction proteins the viral infection caused a relative larger reduction in DLG1 expression for all viruses, suggesting DLG1 may be of particular relevance for ZIKV infections. Taken together, this study contributes to the knowledge of the biological mechanisms involved in ZIKV cytopathogenesis, with a special focus on regional isolates.
... In Brazil, ZIKV was associated with microcephaly, a congenital malformation in newborns. Simultaneously, French Polynesia was associated with Guillain-Barré syndrome, an autoimmune disease in adults leading to paralysis and polyneuropathy [1][2][3]. ...
Zika virus (ZIKV) infections were associated with neurological disorders only after the Brazilian outbreak in 2015. The lack of vaccines and precise diagnosis requires a precise method to detect ZIKV infection. This study aimed to evaluate three ZIKV recombinant proteins for the development of ZIKV infections. Here, it was purified stable recombinant ZIKV Capsid (r-ZIKV-c), non-structural proteins NS1 (r-ZIKV-NS1), and NS3 (r-ZIKV-NS3) for detection of the infection by ZIKV in blood sera of patients. A commercial polyclonal antibody recognized the r-ZIKV-NS1. Here, among three proteins, NS1 showed the best result for diagnostic purposes using serum samples, despite the high similarity with NS1 from DENV, and could differentiate the infections. The recombinant NS1 was used to produce a monoclonal antibody to differentiate between DENV and ZIKV NS1. As for recombinant proteins, the result for r-ZIKV-NS1 values showed 77% and 100% sensitivity and specificity, respectively, in the IgM assay. Our data showed the protein could successfully differentiate between sera of ZIKV infected patients from sera of those not infected with the virus and differentiate from sera of DENV infected patients. Thus, the generated recombinant proteins have great potential for serological diagnosis of ZIKV in Brazil, where it is indispensable .
Zika virus (ZIKV) outbreaks and their adverse clinical consequences have raised concerns throughout the world. ZIKV was little known during the initial outbreaks in Yap islands and French Polynesia, but it came to attention after the series of Brazil outbreaks in which severe complications like microcephaly in newborn babies was detected. During 2018, outbreaks of ZIKV occurred in two states of India which, being a tropical country, has congenial climatic conditions, abundance of highly competent mosquito vectors such as Aedes aegypti and Aedes albopictus, and an immunologically naïve population. In this review, we will briefly discuss the history, epidemiology, evolution, transmission (vector‐borne and non‐vector borne), pathogenesis, clinical signs and unusual presentations, laboratory diagnosis, treatment, prevention and control of ZIKV. Finally, we suggest priorities for urgent research required to address unanswered questions about Zika infections and help bring this virus under control.
Zika virus (ZIKV) is an emerging arthropod-borne flavivirus that, upon infection, results in teratogenic effects and neurological disorders. ZIKV infections pose serious global public health concerns, prompting scientists to increase research on antivirals and vaccines against the virus. These efforts are still ongoing as the pathogenesis and immune evasion mechanisms of ZIKV have not yet been fully elaborated. Currently, no specific vaccines or drugs have been approved for ZIKV; however, some are undergoing clinical trials. Notably, several strategies have been used to develop antivirals, including drugs that target viral and host proteins. Additionally, drug repurposing is preferred since it is less costly and takes less time than other strategies because the drugs used have already been approved for human use. Likewise, different platforms have been evaluated for the design of vaccines, including DNA, mRNA, peptide, protein, viral vectors, virus-like particles (VLPSs), inactivated-virus, and live-attenuated virus vaccines. These vaccines have been shown to induce specific humoral and cellular immune responses and reduce viremia and viral RNA both in vitro and in vivo. Importantly, most of these vaccines have entered clinical trials. Understanding the viral disease mechanism will provide better strategies for developing therapeutic agents against ZIKV. This review provides a comprehensive summary of the viral pathogenesis of ZIKV and current advancements in the development of vaccines and drugs against this virus.
Arboviruses are emerging infectious diseases with the ability to expand geographically and rapidly affect large populations. Arbovirus infections can be more severe in pregnant women than in the general population, facing vertical transmission reported for many arboviruses that severely affect pregnancy outcome. The recent epidemic caused by the Zika virus in the Americas and congenital Zika syndrome associated with maternal infection has called out attention to the importance of studying arboviruses during pregnancy. Some issues that should be focused on are the improvement of diagnostic tests, including specific and sensitive molecular tests, associated with ultrasound screening; more accurate estimates of maternal, fetal, and neonatal risks; and the development of preventive vaccines, among other therapeutic options.
Nanobiotechnology is a promising area of research that has been used to develop technologies to combat Zika virus (ZIKV). This study aims to analyze the patent scenario related to the use of nanobiotechnology in strategies against the ZIKV, using the Orbit Intelligence software. The results point to growth in the number of patent deposits between the years 2015 and 2019. Modernatx, MIT, and Harvard University own 38% of the technologies developed against the ZIKV. The EPO, WIPO, and the United States received 47% of patent protection applications developed by companies with support from techniques in the fields of pharmacology and biotechnology. About 42% of patents found belong to the areas of diagnosis and prevention, designed with the aid of nanoparticles used as delivery systems in vaccines and rapid tests. The results showed that nanobiotechnology is an emerging technology and has been widely used in strategies to stop the ZIKV advance.
Zika virus (ZIKV) is mainly transmitted via mosquitos, but human-to-human transmissions also occur. The virus is shed into various body fluids including saliva, which represents a possible source of viral transmission. Thus, we here explored whether human saliva affects ZIKV infectivity. We found that physiological concentrations of pooled saliva dose-dependently inhibit ZIKV infection of monkey and human cells by preventing viral attachment to target cells. The anti-ZIKV activity in saliva could not be abrogated by boiling, suggesting the antiviral factor is not a protein. Instead, we found that purified extracellular vesicles (EVs) from saliva inhibit ZIKV infection. Salivary EVs (saEVs) express typical EV markers such as tetraspanins CD9, CD63 and CD81 and prevent ZIKV attachment to and infection of target cells at concentrations that are naturally present in saliva. The anti-ZIKV activity of saliva is conserved but the magnitude of inhibition varies between individual donors. In contrast to ZIKV, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), predominantly spreading via respiratory droplets, is not affected by saliva or saEVs. Our findings provide a plausible explanation for why ZIKV transmission via saliva, i.e. by deep kissing have not been recorded and establish a novel oral innate immune defence mechanism against some viral pathogens.
Paper‐based sensors, microfluidic platforms, and electronics have attracted attention in the past couple of decades because they are flexible, can be recycled easily, environmentally friendly, and inexpensive. Here we report a paper‐based potentiometric sensor to detect the whole Zika virus with a minimum sensitivity of 0.26 nV/Zika and a minimum detectable signal (MDS) of 2.4x107 Zika. Our paper sensor works very similar to a P‐N junction where a junction is formed between two different regions with different electrochemical potentials on the paper. These two regions with slightly different ionic contents, ionic species and concentrations, produce a potential difference given by the Nernst equation. Our paper sensor consists of 2‐3 mm x 10 mm segments of paper with conducting silver paint contact patches on two ends. The paper is dipped in a buffer solution containing aptamers designed to bind to the capsid proteins on Zika. We then added the Zika (in its own buffer) to the region close to one of the silver‐paint contacts. The Zika virus (40 nm diameter with 43 kDa or 7.1x10‐20 gm weight) became immobilized in the paper’s pores and bonded with the resident aptamers creating a concentration gradient. Atomic force microscopy and Raman spectroscopy were carried out to verify that both the aptamer and Zika become immobilized in the paper. The potential measured between the two silver paint contacts reproducibly became more negative upon adding the Zika. We also showed that a Liquid Crystalline Display (LCD) powered by the sensor can be used to read the sensor output.
The Zika virus (ZIKV) epidemic is depicted to have high spatial diversity and slow growth, attributable to the dynamics of the mosquito vector and mobility of the human populations. In an effort to understand the transmission dynamics of Zika virus, we formulate a new compartmental epidemic model with a system of seven differential equations and 11 parameters incorporating the decaying transmission rate and study the impact of protection measure on basic public health. We do not fit the model to the observed pattern of spread, rather we use parameter values estimated in the past and examine the extent to which the designed model prediction agrees with the pattern of spread seen in Brazil, via reaction–diffusion modeling. Our work includes estimation of key epidemiological parameters such as basic reproduction number ([Formula: see text], and gives a rough estimate of how many individuals can be typically infected during an outbreak if it occurs in India. We used partial rank correlation coefficient method for global sensitivity analysis to identify the most influential model parameters. Using optimal control theory and Pontryagin’s maximum principle, a control model has been proposed and conditions for the optimal control are determined for the deterministic model of Zika virus. The control functions for the strategies (i) vector-to-human contact reduction and (ii) vector elimination are introduced into the system. Numerical simulations are also performed. This work aimed at understanding the potential extent and timing of the ZIKV epidemic can be used as a template for the analysis of future mosquito-borne epidemics.
A unique field-effect transistor with an active channel composed of aptamers designed to bind to the Zika virus was fabricated. To immobilize the aptamers in the device channel, we used gold nanoparticles (AuNPs), a 20-40 nm thin film of sputtered gold (Au film), and a molecular sieve material zeolite. The aptamers were functionalized with a thiol end group that enabled them to bind with gold and most other materials. In the case of aptamer/AuNP, when Zika was added to the channel it reduced the channel conductivity from 4.4 × 10
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S/cm to 3.7 S/cm. The gate field effect clearly showed that the aptamer/AuNP channel is p-type with a relatively large transconductance of 300 μS (V
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= 2V) compared to the Zika/aptamer/AuNP channel (also p-type) but with lower transconductance of 2 μ S (V
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cm
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) in Zika/aptamer/AuNP channel. In other cases of aptamer/Au film and zeolite channels, there were large changes in the channel conductance when Zika was added. Aptamer/Au and aptamer/zeolite channels were both n-type and their conductivities increased when Zika was added. Combination of AuNP and zeolite biosensing FETs can be used to design complimentary bioFET sensors. We show that the gate voltage in FET biosensors can be used to increase their sensitivity (24 times in Zika/aptamer/AuNP), selectivity and dynamic range (by 10× or more).
Zika virus is transmitted by Aedes mosquitoes, especially, Ae. aegypti and Ae. albopictus. About 80% of the cases do not manifest any symptoms, and it is a self-limiting, mild viral infection. In 20% of the cases and only in fraction of those who do show the symptoms, important complications including Guillaine Barre´syndrome and microcephaly may occur. The emergence of Zika in 2016 in Brazil spreading to about 70 other countries prompted the WHO officials to declare the disease a Public Health Emergency with International Concern (PHEIC). This has led to increased concerns in health authorities of almost all countries making them embark on the strengthened human and vector surveillance, vector control and clinical management of the disease. Although the main vectors of the disease have not yet been able to establish in Iran, because of their occurrence in neighboring countries as well as increased global travel and trade, the country established a national advisory committee for capacity building, vector and human surveillance and case management of Aedes-borne diseases. This study aims at performing a literature review about global situation of Zika and Aedes mosquitoes, their distribution, biology and ecology from the past to present and the threat posed to Iran. Aedes aegypti was historically present in the checklist of Iranian mosquitoes and Ae. albopictus has recently been collected from Southern Iran, however, the species has apparently failed to establish in the country as comprehensive follow up entomological surveillance could not reproduce the findings. Although Zika was not detected in Iran, considering the expansion in tourism, travel and trade to and from Zika infected and Aedes infested countries, suitable climate and favorable prediction for establishment of Aedes vectors, Iran may well be at risk of invasion of Aedes vector species and the diseases they carry. Therefore, this review is of value particularly to health authorities in Iran and other WHO Eastern Mediterranean countries for sustained vigilance and preparedness for early detection and response, including vector control.
Zika virus (ZIKV) has been recently recognized as a causative agent of newborn microcephaly, as well as other neurological consequences. A less well recognized comorbidity of prenatal ZIKV infection is hearing loss, but cases of hearing impairment following adult ZIKV infection have also been recognized. Diminished hearing following prenatal ZIKV infection in a mouse model has been reported, but no cellular consequences were observed. We examined the effects of ZIKV infection on inner ear cellular integrity and expression levels of various proteins important for cochlear function in type I interferon receptor null (Ifnar1-/-) mice following infection at 5-6 weeks of age. We show that ZIKV antigens are present in cells within the cochlear epithelium, lateral wall, spiral limbus and spiral ganglion. Here we show that ZIKV infection alters cochlear expression of genes that signal cell damage (S100B), transport fluids (AQP1), are gaseous transmitters (eNOs) and modulate immune response (F4/80). Morphological analyses shows that not only are cochlear structures compromised by ZIKV infection, but damage also occurs in vestibular end organs. ZIKV produces a graded distribution of cellular damage in the cochlea, with greatest damage in the apex similar to that reported for cytomegalovirus (CMV) infection. The graded distribution of damage may indicate a differential susceptibility to ZIKV along the cochlear tonotopic axis. Collectively, these data are the first to show the molecular and morphological damage to the inner ear induced by ZIKV infection in adults and suggests multiple mechanisms contributing to the hearing loss reported in the human population.
Mosquito-borne and sexual transmission of Zika virus (ZIKV), a TORCH pathogen, recently initiated a series of large epidemics throughout the Tropics. Animal models are necessary to determine transmission risk and study pathogenesis, as well screen antivirals and vaccine candidates. In this study, we modeled mosquito and sexual transmission of ZIKV in the African green monkey (AGM). Following subcutaneous, intravaginal or intrarectal inoculation of AGMs with ZIKV, we determined the transmission potential and infection dynamics of the virus. AGMs inoculated by all three transmission routes exhibited viremia and viral shedding followed by strong virus neutralizing antibody responses, in the absence of clinical illness. All four of the subcutaneously inoculated AGMs became infected (mean peak viremia: 2.9 log10 PFU/mL, mean duration: 4.3 days) and vRNA was detected in their oral swabs, with infectious virus being detected in a subset of these specimens. Although all four of the intravaginally inoculated AGMs developed virus neutralizing antibody responses, only three had detectable viremia (mean peak viremia: 4.0 log10 PFU/mL, mean duration: 3.0 days). These three AGMs also had vRNA and infectious virus detected in both oral and vaginal swabs. Two of the four intrarectally inoculated AGMs became infected (mean peak viremia: 3.8 log10 PFU/mL, mean duration: 3.5 days). vRNA was detected in oral swabs collected from both of these infected AGMs, and infectious virus was detected in an oral swab from one of these AGMs. Notably, vRNA and infectious virus were detected in vaginal swabs collected from the infected female AGM (peak viral load: 7.5 log10 copies/mL, peak titer: 3.8 log10 PFU/mL, range of detection: 5–21 days post infection). Abnormal clinical chemistry and hematology results were detected and acute lymphadenopathy was observed in some AGMs. Infection dynamics in all three AGM ZIKV models are similar to those reported in the majority of human ZIKV infections. Our results indicate that the AGM can be used as a surrogate to model mosquito or sexual ZIKV transmission and infection. Furthermore, our results suggest that AGMs are likely involved in the enzootic maintenance and amplification cycle of ZIKV.
Introduction:
The objective of this study is to assess the oral and maxillofacial characteristics of microcephalic children associated with congenital Zika syndrome (CZS).
Methods:
A cross-sectional, observational study was carried out with 61 patients with microcephaly/CZS born between June 2015 and September 2017 (29 boys and 32 girls, average age of 22.8 months) and a control group with 58 non-CZS children born in the same period (25 boys and 33 girls, average age of 23.8 months). The functional clinical analysis considered the labial and lingual frena, tongue anterior projection, oral escape, palate form, and first tooth eruption. For the craniofacial analysis, facial anthropometric points and the cephalic perimeter at the time were measured. Demographic data were collected from medical records, and a clinical exam was performed in order to register the intrabuccal characteristics and craniofacial measures. The chi-square test and Student's t-test were used with a significance level of 0.05.
Results:
The narrow palate form, tongue anterior projection, oral escape, and late first tooth eruption were significantly more present in the group with microcephaly/CZS. As for the craniofacial analysis, face width (Bi-Zi), mandible width (Go-Go), height of face upper third (Tr-G), and monthly growth of cephalic perimeter were significantly smaller, whereas height of face lower third (Sn-Gn) was significantly bigger in the group with microcephaly/CZS (P < 0.05).
Conclusion:
Children with microcephaly resulting from a congenital Zika infection showed functional, oral, and maxillofacial changes and smaller facial development in comparison with non-CZS children in the same age group.
Virologic surveillance of Japanese encephalitis virus (JEV) relies on collecting pig blood specimens and adult mosquitoes in the past. Viral RNAs extracted from pig blood specimens suffer from low detecting positivity by reverse transcription PCR (RT-PCR). The oronasal transmission of the virus has been demonstrated in experimentally infected pigs. This observation suggested oronasal specimens could be useful source in the virus surveillance. However, the role of this unusual route of transmission remains unproven in the operational pig farm. In this study, we explore the feasibility of using pig oronasal secretions collected by chewing ropes to improve the positivity of detection in commercial pig farms. The multiplex genotype-specific RT-PCR was used in this study to determine and compare the positivity of detecting JEV viral RNAs in pig’s oronasal secretions and blood specimens, and the primary mosquito vector. Oronasal specimens had the overall positive rate of 6.0% (95% CI 1.3%–16.6%) (3/50) to 10.0% (95% CI 2.1%–26.5%) (3/30) for JEV during transmission period despite the negative results of all blood-derived specimens ( n = 2442). Interestingly, pig oronasal secretions and female Culex tritaeniorhynchus mosquito samples collected from the same pig farm showed similar viral RNA positive rates, 10.0% (95% CI 2.1%–26.5%) (3/30) and 8.9% (95% CI 2.5%–21.2%) (4/45), respectively ( p > 0.05). Pig oronasal secretion-based surveillance revealed the seasonality of viral activity and identified closely related genotype I virus derived from the mosquito isolates. This finding indicates oronasal secretion-based RT-PCR assay can be a non-invasive, alternative method of implementing JEV surveillance in the epidemic area prior to the circulation of virus-positive mosquitoes.
Dengue is an important arthropod-borne viral disease in terms of morbidity, mortality, economic impact and challenges in vector control. Benchmarks are expensive, time consuming and require trained personnel. Preventing dengue complications with rapid diagnosis has been based on the testing of easy-to-perform optimized immunochromatographic methods (ICT). This is a systematic meta-analysis review of the diagnostic accuracy of IgA, NS1, IgM and/or IgG ICT studies in suspected cases of acute or convalescent dengue, using a combination of RT-PCR, ELISA NS1, IgM IgG or viral isolation as a reference standard. This protocol was registered in PROSPERO (CRD42014009885). Two pairs of reviewers searched the PubMed, BIREME, Science Direct, Scopus, Web of Science, Ovid MEDLINE JBrigs, SCIRUS and EMBASE databases, selected, extracted, and quality-assessed by QUADAS 2. Of 3,783 studies, we selected 57, of which 40 in meta-analyses according to the analyte tested, with high heterogeneity (I2 > 90%), as expected for diagnostic tests. We detected higher pooled sensitivity in acute phase IgA (92.8%) with excellent (90%) specificity. ICT meta-analysis with NS1/IgM/IgG showed 91% sensitivity and 96% specificity. Poorer screening performance was for IgM/IgG ICT (sensitivity = 56%). Thus, the studies with NS1/IgM/IgG ICT showed the best combined performance in the acute phase of the disease.
SARS-CoV-2 was detected from at least 1 buccal specimen in 9 out of 11 COVID-19-infected children (81.8%). The viral loads in buccal specimens were substantially lower than those in nasopharyngeal specimens. Buccal swabs for SARS-CoV-2 are not good as screening specimens for COVID-19 in children.
To advance a novel concept of debulking virus in the oral cavity, the primary site of viral replication, virus trapping proteins CTB-ACE2 were expressed in chloroplasts and clinical grade plant material was developed to meet FDA requirements. Chewing gum (2 grams) containing plant cells expressed CTB-ACE2 up to17.2 mg ACE2/g DW (11.7% leaf protein) have physical characteristics, taste/flavor like conventional gums and no protein was lost during gum compression. CTB-ACE2 gum efficiently (>95%) inhibited entry of Lentivirus-Spike or VSV-Spike pseudovirus into Vero/CHO cells, when quantified by luciferase or red fluorescence. Incubation of CTB-ACE2 microparticles reduced SARS-CoV- 2 virus count in COVID-19 swab/saliva samples >95%, when evaluated by microbubbles (femtomolar concentration) or qPCR, demonstrating both virus trapping and blocking of cellular entry. COVID-19 saliva samples showed low or undetectable ACE2 activity when compared to healthy individuals (2582 vs 50126 ΔRFU; 27 vs 225 enzyme units), confirming greater susceptibility of infected patients for viral entry. CTB-ACE2 activity was completely inhibited by pre-incubation with SARS-COV-2 RBD, offering an explanation for reduced saliva ACE2 activity among COVID-19 patients. Chewing gum with virus trapping proteins offers a general affordable strategy to protect patients from most oral virus reinfections through debulking or minimizing transmission to others.
Zika virus was first discovered in the Zika Forest of Uganda in 1947 and was until recently believed to be an infection of mild clinical significance. Infection with Zika virus presents with mild clinical symptoms including fever, headache, rash, conjunctivitis, arthralgia, and myalgia—only a small proportion of laboratory-confirmed infections manifested clinically detectable features. In 2016 the World Health Organization declared Zika virus infection and its associated congenital malformations and neurological disorders as a Public Health Emergency of International Concern, following a large-scale outbreak of microcephaly in Brazil. Molecularly confirmed or serologically confirmed acute Zika virus infection was associated with an increased incidence of a spectrum of significant neurological manifestations including Guillain-Barré syndrome, encephalitis, and transverse myelitis. Zika virus infection during the perinatal period results in congenital Zika syndrome, a condition characterized by microcephaly, reduced head circumference, and significant craniofacial disproportion. Although Zika virus is no longer a Public Health Emergency of International Concern, Zika virus screening during pregnancy in endemic regions remains relevant and necessary, due to the severe long-term sequelae and cost to the healthcare systems involved.
Microfabricated silicon nitride cantilever beams, with gold disks and triangles were used to study and quantify residual stresses generated by binding with the thiol end groups of Zika aptamers and then with Zika. Binding with aptamers and Zika generated large tensile residual stresses ~ 53 MPa that deflected the beams and changed their reflective color. It also caused the triangular gold patches to detach from their nitride substrates affecting the substrates' “golden” color. Dynamic measurements of the nitride beams' vibrations were used to measure mass loading by Zika with the sensitivity of 2 kHz/ng. The residual stress built-up due to binding with Zika in excess of 9 × 10
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Zika/beam caused nitride beams to buckle. Zika-induced residual stress measured using the triangular patches was 96 MPa. Large-scale cellulose acetate beams were then used to observe the residual stresses caused by 20 nm gold layer (0.24 MPa), aptamers (0.3 MPa), and then with Zika (0.5 MPa). Acetate beam displacement was used to “sense” Zika with 2 x 10
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μm/Zika sensitivity.
Sensitive viral diagnostic methods are increasingly in demand to tackle emerging epidemics. The Zika virus (ZIKV) is particularly relevant in tropical resource limited settings (RLS) and is associated with intermittent epidemics such as the recent 2016 ZIKV outbreak in South America, wherein Zika fever was classified by WHO as a public health emergency of international concern. Thus, there is an urgent need for widespread Zika fever diagnostics and efficient drug therapies.
ZIKV diagnostics are typically performed using RT-qPCR in centralized laboratories. While extremely sensitive, RT-qPCR requires rapid heating-cooling cycles, combined with continuous fluorescence measurements to allow quantification, implying high costs and limiting availability of molecular diagnostics in RLS. Here, we report isothermal amplification of ZIKV cDNA using padlock probes followed by two rounds of Rolling Circle Amplification (RCA), combined with a microfluidic affinity chromatography enrichment (μACE) platform. This platform allowed the detection of <17 vRNA copies per reaction mixture, equivalent to ∼3 aM, showed a positive correlation with RT-qPCR in both average (r = 0.80) and discrete (r = 0.95) signal modes, and was validated for drug efficiency tests using in vitro infected peripheral blood mononuclear cells from 3 healthy donors. This performance shows significant promise towards highly sensitive, albeit simple and cost-effective point-of-care viral diagnostics.
The Zika virus (ZIKV) epidemic is a challenge for scientists and health professionals due to the large spread of mosquitoes. This work aimed to describe the main control strategies of ZIKV when using pesticides. The methodology consisted of a literature review on the use of pesticides in potential mosquito breeding sites. Pyriproxyfen (PPF) stood out in the control of Aedes aegypti L. (species of mosquito that causes ZIKV) with dissemination in its particles through the ultra low volume technique. Its use was satisfactory since the PPF does not pose a risk to humans. However, an effective control of the epidemic requires integration with mechanical, biological, and chemical control to eliminate or reduce the mosquito population. For this, studies are essential to validate the proposed strategies, as well as financial investments for the continuity of control actions and implementation of government health campaigns.
Background
Zika (ZIKV) is a mosquito-borne virus that has caused multiple outbreaks in Americas. The early and accurate diagnosis of ZIKV is the key to minimise the health burden imposed on the infected patients. Many commercial ZIKV diagnosis kit are available based on ZIKV envelope antigen with varying sensitivity and specificity.
Objective
The aim of this study was to develop sensitive ELISA methodology based on recombinant ZIKV NS1 and NS1 β-ladder antigens for seroprevalence detection in a cohort of patients in an arbovirus endemic Mexican region in comparison to a commercial kit.
Study design
We obtained serum samples from 60 patients presenting with febrile illness and from 10 healthy donors in Michoacán state in 2016-2017. These samples were screened for ZIKV by RT-PCR and used to develop NS1 based ELISA and compared to a commercial kit.
Results
Our results indicate that both ZIKV sNS1 and β-ladder-based ELISA can reliably detect anti-ZIKV NS1 antibodies in infected patients, relevant for the serodiagnosis of ZIKV. Determination of antibody titers showed that it offered higher sensitivity than a commercially available ZIKV ELISA. Over 90% seropositivity against ZIKV for the febrile patients in Lázaro Cárdenas which is an arboviral endemic region while lower seropositivity was observed in the healthy volunteers in Morelia (non-endemic area).
Conclusion
We conclude that our simple and sensitive in-house NS1 based ELISA used in this study has excellent sensitivity, is easy to use and can provide fast results suitable for larger population-based seroprevalence studies in the future.
The recent Zika virus (ZIKV) epidemic poses a serious threat to global health due to its association with microcephaly and congenital diseases in newborns and neurological complications and Guillain-Barré syndrome in adults. However, the majority of people infected with ZIKV do not develop symptoms. The platforms aimed to specifically diagnose ZIKV infection are needed for patient care and public health surveillance. In the study, four ZIKV envelope (E) protein-specific monoclonal antibodies (mAbs) (A1, B1, C1, and 9E-1) have been developed by using the conventional mAb technology. The binding epitopes of mAbs A1, B1, C1, and 9E-1 are located at E(238-257), E(410-431), E(258-277), and E(340-356), respectively. mAb 9E-1 performs 1.4- to 47-fold strong affinity to ZIKV E protein compared to another three mAbs. mAbs A1, C1, and 9E-1 do not have cross-reactivity against the recombinant E proteins of dengue virus serotypes 2, 3, and 4. Although these four mAbs do not have ZIKV neutralizing activity, mAbs B1 and 9E-1 have been developed as the lateral flow immunochromatographic assay for specific detection of ZIKV E protein and virions.
Key points
• The mAbs targeting to the regions of E(238-257), E(410-431), E(258-277), and E(340-356) do not have ZIKV neutralizing activity.
• The binding epitope of mAb 9E-1 is highly specific to ZIKV E protein.
• mAbs B1 and 9E-1 can bind to ZIKV virions and have been developed as the lateral flow immunochromatographic assay.
In 2016, during the American Zika virus (ZIKV) outbreak, the interest in a rapid diagnosis intensified due to a sudden increase in cases of Guillain-Barré syndrome in adults and microcephaly in newborns of infected pregnant women related to ZIKV. According to CDC the diagnosis of symptomatic patients should be done through nucleic acid detection by qPCR in paired samples of blood and urine. The chapter goes on to discuss research using saliva analyzed through loop-mediated Isothermal amplification (LAMP) as feasible alternative to diagnose ZIKV compared with urine. Saliva requires less processing than blood, which greatly simplifies the assay process, and LAMP is a molecular test with high sensibility and specificity for rapid detection of DNA or RNA of pathogens, including ZIKV. The recent findings are contributing to the knowledge of the ZIKV behavior in the human organism improving the diagnostic methods.
Introduction
Molecular technology has played an important role in arboviruses diagnostics. PCR-based methods stand out in terms of sensitivity, specificity, cost, robustness, and accessibility, and especially the isothermal amplification (IA) method is ideal for field-adaptable diagnostics in resource-limited settings (RLS).
Areas covered
In this review, we provide an overview of the various molecular methods for West Nile, Zika, Dengue and Chikungunya. We summarize literature works reporting the assessment and use of in house and commercial assays. We describe limitations and challenges in the usage of methods and opportunities for novel approaches such as Next Generation Sequencing (NGS).
Expert opinion
The rapidity and accuracy of differential diagnosis is essential for a successful clinical management, particularly in co-circulation area of arboviruses. Several commercial diagnostic molecular assays are available, but many are not affordable by RLS and not usable as Point-of-care/Point-of-need (POC/PON) such as Real Time RT-PCR, Array-based methods and NGS. In contrast, the IA-based system fits better for POC/PON but it is still not ideal for the multiplexing detection system. Improvement in the characterization and validation of current molecular assays is needed to optimize their translation to the point of care.
Zika virus (ZIKV) is a widespread flavivirus transmitted to humans through the bite of Aedes mosquitoes. The number of ZIKV cases increased significantly between 2015 and 2016, and Brazil was the first to report autochthonous transmission of infection. The main neurological disorder related to ZIKV infection is microcephaly. Fetal magnetic resonance imaging (MRI) is the gold standard examination for the analysis of fetal brain infection, followed by obstetric ultrasonography. Cerebral atrophy, intracranial calcifications, ventriculomegaly, cerebellar, and brain gyrus abnormalities are some of the most common findings. Postnatal MRI shows high sensitivity and specificity. Corpus callosum abnormalities, cerebellar hypoplasia, and choroid plexus dilation can be also observed. We present a review of congenital ZIKV infection with emphasis on pre and postnatal brain findings using ultrasonography, MRI, computed tomography, and three-dimensional reconstruction models.
We have previously developed and validated a one-step assay based on reverse transcription loop-mediated isothermal amplification (RT-LAMP) for rapid detection of the Zika virus (ZIKV) from mosquito samples. Patient diagnosis of ZIKV is currently carried out in centralized laboratories using the reverse transcription-quantitative polymerase chain reaction (RT-qPCR), which, while the gold standard molecular method, has several drawbacks for use in remote and low-resource settings, such as high cost and the need of specialized equipment. Point-of-care (POC) diagnostic platforms have the potential to overcome these limitations, especially in low-resource countries where ZIKV is endemic. With this in mind, here we optimized and validated our RT-LAMP assay for rapid detection of ZIKV from patient samples. We found that the assay detected ZIKV from diverse sample types (serum, urine, saliva, and semen) in as little as 20 min, without RNA extraction. The RT-LAMP assay was highly specific and up to 100 times more sensitive than RT-qPCR. We then validated the assay using 100 patient serum samples collected from suspected cases of arbovirus infection in the state of Pernambuco, which was at the epicenter of the last Zika epidemic. Analysis of the results, in comparison to RT-qPCR, found that the ZIKV RT-LAMP assay provided sensitivity of 100%, specificity of 93.75%, and an overall accuracy of 95.00%. Taken together, the RT-LAMP assay provides a straightforward and inexpensive alternative for the diagnosis of ZIKV from patients and has the potential to increase diagnostic capacity in ZIKV-affected areas, particularly in low and middle-income countries.
We evaluated sweat, blood and urine specimens obtained from an ongoing cohort study in Brazil. Samples were collected at pre-established intervals after the initial rash presentation and tested for Zika virus (ZIKV) RNA presence by real-time reverse transcriptase polymerase chain reaction (rRT-PCR). From 254 participants with confirmed infection, ZIKV RNA was detected in the sweat of 46 individuals (18.1%). Sweat presented a median cycle threshold (Ct) of 34.74 [interquartile range (IQR) 33.44-36.04], comparable to plasma (Ct 35.96-IQR 33.29-36.69) and higher than urine (Ct 30.78-IQR 28.72-33.22). Concomitant detection with other specimens was observed in 33 (72%) of 46 participants who had a positive result in sweat. These findings represent an unusual and not yet investigated virus shedding through eccrine glands.me
Zika virus (ZIKV) has emerged as a particularly notorious mosquito-borne flavivirus, which can lead to a devastating congenital syndrome in the fetuses of pregnant mothers (e.g., microcephaly, spasticity, craniofacial disproportion, miscarriage, and ocular abnormalities) and cause the autoimmune disorder Guillain-Barre' syndrome of adults. Due to its severity and rapid dispersal over several continents, ZIKV has been acknowledged to be a global health concern by the World Health Organization. Unfortunately, the ZIKV has recently resurged in India with the potential for devastating effects. Researchers from all around the world have worked tirelessly to develop effective detection strategies and vaccines for the prevention and control of ZIKV infection. In this review, we comprehensively summarize the most recent research into ZIKV, including the structural biology and evolution, historical overview, pathogenesis, symptoms, and transmission. We then focus on the detection strategies for ZIKV, including viral isolation, serological assays, molecular assays, sensing methods, reverse transcription loop mediated isothermal amplification, transcription-mediated amplification technology, reverse transcription strand invasion based amplification, bioplasmonic paper-based device, and reverse transcription isothermal recombinase polymerase amplification. To conclude, we examine the limitations of currently available strategies for the detection of ZIKV, and outline future opportunities and research challenges.
Introduction
Over the past decade, loop-mediated isothermal amplification (LAMP) technology has played an important role in molecular diagnostics. Amongst numerous nucleic acid amplification assays, LAMP stands out in terms of sample-to-answer time, sensitivity, specificity, cost, robustness, and accessibility, making it ideal for field-deployable diagnostics in resource-limited regions.
Areas covered
In this review, we outline the front-end LAMP design practices for point-of-care (POC) applications, including sample handling and various signal readout methodologies. Next, we explore existing LAMP technologies that have been validated with clinical samples in the field. We summarize recent work that utilizes reverse transcription (RT) LAMP to rapidly detect SARS-CoV-2 as an alternative to standard PCR protocols. Finally, we describe challenges in translating LAMP from the benchtop to the field and opportunities for future LAMP assay development and performance reporting.
Expert Opinion
Despite the popularity of LAMP in the academic research community and a recent surge in interest in LAMP due to the COVID-19 pandemic, there are numerous areas for improvement in the fundamental understanding of LAMP, which are needed to elevate the field of LAMP assay development and characterization.
Surface-enhanced Raman scattering (SERS) technology was combined with nanotechnology to detect the Raman intensity of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in saliva and of three kinds of populations (healthy volunteers, patients with gingivitis, and patients with periodontitis). The Raman intensities of IL-1β and TNF-α in the saliva of the periodontitis group were significantly higher than those of the control and gingivitis groups (P = 0.00). The Raman intensities of the two inflammatory factors in the gingival crevicular fluid (GCF) of the periodontitis group were also significantly higher than those of the other two groups (P = 0.00). In the same group, the Raman intensities of IL-1β and TNF-α showed no significant difference between the saliva and GCF samples, respectively (P > 0.05). Combining SERS technology and nanotechnology can aid in detecting the Raman intensity of inflammatory factors using saliva and GCF more effectively than traditional methods.
Zika virus is an arthropod-borne flavivirus mainly transmitted by the bite of infected mosquitoes. However, alternative transmission routes can occur. In this study, we show the accidental transmission of virus from an infected mouse to a human during the experimental manipulation. This study describes the patient clinical manifestations and virus genome identification.
Background
Early detection of Zika virus (ZIKV) infection during the viremia and viruria facilitates proper patient management and mosquito control measurement to prevent disease spread. Therefore, a cost-effective nucleic acid detection method for the diagnosis of ZIKV infection, especially in resource-deficient settings, is highly required.
Methods
In the present study, a single-tube reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed for the detection of both the Asian and African-lineage ZIKV. The detection limit, strain coverage and cross-reactivity of the ZIKV RT-LAMP assay was evaluated. The sensitivity and specificity of the RT-LAMP were also evaluated using a total of 24 simulated clinical samples. The ZIKV quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assay was used as the reference assay.
Results
The detection limit of the RT-LAMP assay was 3.73 ZIKV RNA copies (probit analysis, P ≤ 0.05). The RT-LAMP assay detected the ZIKV genomes of both the Asian and African lineages without cross-reacting with other arthropod-borne viruses. The sensitivity and specificity of the RT-LAMP assay were 90% (95% CI = 59.6–98.2) and 100% (95% CI = 78.5–100.0), respectively. The RT-LAMP assay detected ZIKV genome in 9 of 24 (37.5%) of the simulated clinical samples compared to 10 of 24 (41.7%) by qRT-PCR assay with a high level of concordance (κ = 0.913, P < 0.001).
Conclusion
The RT-LAMP assay is applicable for the broad coverage detection of both the Asian and African ZIKV strains in resource-deficient settings.
Molecular detection of Zika virus (ZIKV) contributes to efficacious diagnosis and epidemiological investigation. Here, we review the methods of viral detection for various body fluids. We comprehensively outline the recommended methods for viral RNA extraction from body fluids, most of which require alterations to manufacturer instructions to maximize RNA recovery. Although current agency-approved ZIKV diagnostic guidelines rely on serum alone, sampling of multiple body fluid types significantly elevates the sensitivity of testing, with genitourinary, whole blood, and cerebrospinal fluids offering longer windows for detection.
Mosquito-borne flavivirus is associated with the zika virus (ZIKV) which is the attention of numerous public health hazards & enduring epidemic for many years and was first identified in 1947. Formerly partial to sporadic cases in Asia & Africa but in Brazil, the zika virus appearance in 2015 indicated fast spreading all over Americans. It has been acknowledged as a global public health emergency by the World Health Organization (WHO) in 2016. Symptoms normally appear as mild-influenza, neurological signs, and subclinical manifestations with the syndrome of microcephaly in offspring that are born from infected mothers & Guillain-Barré syndrome (GBS) in adults. There is no cure or effective Zika Virus treatment known to date. Easy and efficient detection of the zika virus can reduce the risk of sickness and the successful management of this disease. Conventional techniques currently available are focused on clinical manifestation, along with molecular and serological detection tools that can identify the zika virus but due to their various disadvantages such as low specificity and sensitivity, there is a need for a quick and easy approach for the diagnosis of zika virus. Scientists are showing great interest in an effective portable and simple detection method to diagnose the Zika virus. Biosensor is considered a viable advanced system that can meet all the aforementioned demands. Biosensors are combined with an effortless approach to allow them for exploiting in various applications. This review summarizes the diagnosis, surveillance, and advancement in sensing technology for easy and successful detection of Zika virus and its usage as a fast and rapid analytical tool.
We describe the kinetics of Zika virus (ZIKV) detection in serum and urine samples of 6 patients. Urine samples were positive for ZIKV >10 days after onset of disease, which was a notably longer period than for serum samples. This finding supports the conclusion that urine samples are useful for diagnosis of ZIKV infections.
Zika virus (ZIKV) is an emerging arthropod-borne virus (arbovirus) belonging to the Flaviviridae family and Flavivirus genus. ZIKV was first isolated from a monkey in the Zika forest of Uganda in 1947 [1]. Subsequently, sporadic human infections were reported in Africa and Asia. In 2007, the first large documented ZIKV outbreak was reported from Yap State, Federated States of Micronesia [2]. No further transmission was identified in the Pacific until October 2013 when French Polynesia (FP) reported the first cases; a subsequent explosive outbreak resulted in an estimated 28,000 cases seeking medical care (~11% of the population) [3,4]. This article is protected by copyright. All rights reserved.
Since October 2013, French Polynesia has experienced the largest documented outbreak of Zika virus (ZIKAV) infection. To prevent transmission of ZIKAV by blood transfusion, specific nucleic acid testing of blood donors was implemented. From November 2013 to February 2014: 42 (3%) of 1,505 blood donors, although asymptomatic at the time of blood donation, were found positive for ZIKAV by PCR. Our results serve to alert blood safety authorities about the risk of post-transfusion Zika fever.
A Zika virus (ZIKAV) outbreak started in October 2013 in French Polynesia, South Pacific. We describe here the clinical and laboratory features of two mothers and their newborns who had ZIKAV infection as confirmed by ZIKAV RT-PCR performed on serum collected within four days post-delivery in date. The infants' infection most probably occurred by transplacental transmission or during delivery. Attention should be paid to ZIKAV-infected pregnant women and their newborns, as data on the impact on them are limited.
The reemergence of dengue virus (DENV) infection has created a requirement for improved laboratory diagnostic procedures.
In this study, DENV genome detection in urine was evaluated as a diagnostic method. The DENV genome was detected by real-time
reverse transcriptase PCR (RT-PCR) in urine and serum of dengue patients. The detection rate of DENV genome in urine was 25%
(2/8) on disease days 0 to 3 and 32% (7/22) on days 4 to 5. The rate was 50% or higher on days 6 to 16, 52% (11/21) on days
6 to 7, 78% (7/9) on days 8 to 9, 80% (4/5) on days 10 to 11, 50% (2/4) on days 12 to 13, and 60% (3/5) on days 14 to 16.
The last positive urine sample was on day 16. The detection rates in serum were highest on days 0 to 3 and were greater than
50% on days 0 to 7. Detection rates decreased thereafter, and the last positive detection was on day 11. These results indicate
that the time frames for positive detection differ between urine and serum samples, whereby detection rates of 50% or higher
are evident between days 6 to 16 for urine samples and days 0 to 7 for serum samples. Nucleotide sequences of PCR products
were identical between urine and serum samples. The detection of DENV genome in urine samples by real-time RT-PCR is useful
to confirm DENV infection, particularly after viremia disappears.
Early diagnosis of dengue virus (DENV) infection is important for patient management and control of dengue outbreaks. The objective of this study was to analyze the usefulness of urine and saliva samples for early diagnosis of DENV infection by real time RT-PCR. Two febrile patients, who have been attended at the General Hospital of the School of Medicine of Ribeirao Preto, Sao Paulo University were included in the study. Serum, urine and saliva samples collected from both patients were subjected to real time RT-PCR for DENV detection and quantification. Dengue RNA was detected in serum, urine and saliva samples of both patients. Patient 1 was infected with DENV-2 and patient 2 with DENV-3. Data presented in this study suggest that urine and saliva could be used as alternative samples for early diagnosis of dengue virus infection when blood samples are difficult to obtain, e.g., in newborns and patients with hemorrhagic syndromes.
Zika virus (ZIKV) is a flavivirus related to yellow fever, dengue, West Nile, and Japanese encephalitis viruses. In 2007 ZIKV caused an outbreak of relatively mild disease characterized by rash, arthralgia, and conjunctivitis on Yap Island in the southwestern Pacific Ocean. This was the first time that ZIKV was detected outside of Africa and Asia. The history, transmission dynamics, virology, and clinical manifestations of ZIKV disease are discussed, along with the possibility for diagnostic confusion between ZIKV illness and dengue.The emergence of ZIKV outside of its previously known geographic range should prompt awareness of the potential for ZIKV to spread to other Pacific islands and the Americas.
In 2007, physicians on Yap Island reported an outbreak of illness characterized by rash, conjunctivitis, and arthralgia. Although serum from some patients had IgM antibody against dengue virus, the illness seemed clinically distinct from previously detected dengue. Subsequent testing with the use of consensus primers detected Zika virus RNA in the serum of the patients but no dengue virus or other arboviral RNA. No previous outbreaks and only 14 cases of Zika virus disease have been previously documented.
We obtained serum samples from patients and interviewed patients for information on clinical signs and symptoms. Zika virus disease was confirmed by a finding of Zika virus RNA or a specific neutralizing antibody response to Zika virus in the serum. Patients with IgM antibody against Zika virus who had a potentially cross-reactive neutralizing-antibody response were classified as having probable Zika virus disease. We conducted a household survey to estimate the proportion of Yap residents with IgM antibody against Zika virus and to identify possible mosquito vectors of Zika virus.
We identified 49 confirmed and 59 probable cases of Zika virus disease. The patients resided in 9 of the 10 municipalities on Yap. Rash, fever, arthralgia, and conjunctivitis were common symptoms. No hospitalizations, hemorrhagic manifestations, or deaths due to Zika virus were reported. We estimated that 73% (95% confidence interval, 68 to 77) of Yap residents 3 years of age or older had been recently infected with Zika virus. Aedes hensilli was the predominant mosquito species identified.
This outbreak of Zika virus illness in Micronesia represents transmission of Zika virus outside Africa and Asia. Although most patients had mild illness, clinicians and public health officials should be aware of the risk of further expansion of Zika virus transmission.
Zika virus (ZIKV) is a mosquito-borne flavivirus first isolated in Uganda from a sentinel monkey in 1947. Mosquito and sentinel animal surveillance studies have demonstrated that ZIKV is endemic to Africa and Southeast Asia, yet reported human cases are rare, with <10 cases reported in the literature. In June 2007, an epidemic of fever and rash associated with ZIKV was detected in Yap State, Federated States of Micronesia. We report the genetic and serologic properties of the ZIKV associated with this epidemic.
The dengue (DEN) viruses are positive-strand RNA viruses in the genus Flavivirus. Dengue fever and dengue hemorrhagic fever/dengue shock syndrome are important human arboviral diseases caused by infection with one of four closely related but serologically distinct DEN viruses, designated DEN-1, DEN-2, DEN-3, and DEN-4 viruses. All four DEN serotypes are currently co-circulating throughout the subtropics and tropics, and genotypic variation occurs among isolates within a serotype. A real-time quantitative nucleic acid amplification assay has been developed to detect viral RNA of a single DEN virus serotype. Each primer-probe set is DEN serotype specific, yet detects all genotypes in a panel of 7 to 10 representative isolates of a serotype. In single reactions and in fourplex reactions (containing four primer-probe sets in a single reaction mixture), standard dilutions of virus equivalent to 0.002 PFU of DEN-2, DEN-3, and DEN-4 viruses were detected; the limit of detection of DEN-1 virus was 0.5 equivalent PFU. Singleplex and fourplex reactions were evaluated in a panel of 40 viremic serum specimens with 10 specimens per serotype, containing 0.002 to 6,000 equivalent PFU/reaction (0.4 to 1.2 x 10(6) PFU/ml). Viral RNA was detected in all viremic serum specimens in singleplex and fourplex reactions. Thus, this serotype-specific, fourplex real-time reverse transcriptase PCR nucleic acid detection assay can be used as a method for differential diagnosis of a specific DEN serotype in viremic dengue patients and as a tool for rapid identification and serotyping of DEN virus isolates.
Detection of West Nile virus (WNV) RNA in urine has been anecdotally described and proposed for the diagnosis of WNV infection.
This study reports the routine use of real-time reverse-transcription polymerase chain reaction for the detection of WNV RNA
in urine to support diagnosis of WNV infection during the large outbreak that occurred in northeastern Italy in 2012. Fourteen
of 32 patients (43.8%) with symptomatic WNV infection, defined as neuroinvasive disease and fever, had detectable WNV RNA
in urine at the time of diagnosis, at a higher rate and load and for a longer time than detection of WNV RNA in blood. Detection
of WNV RNA in urine was less frequent (2 of 14 patients [14.2%]) in blood donors in whom WNV infection was identified by WNV
nucleic acid amplification testing. Infectious virus was isolated from the urine of a patient with neuroinvasive disease and
a high WNV RNA load in urine.
• 1.(1) The isolation of what is believed to be a hitherto unrecorded virus is described. The first isolation was made in April 1947 from the serum of a pyrexial rhesus monkey caged in the canopy of Zika Forest. The second isolation was made from a lot of A. africanus taken in January, 1948, in the same forest. The virus has been called Zika virus after the locality from where the isolations were made.
• 2.(2) Cross neutralization tests indicate that Zika virus is not related to yellow fever, Hawaii dengue nor to the FA and GD VII strains of Theiler's mouse encephalomyelitis virus. Neutralization tests with Zika virus and the antisera of some other viruses which are neurotropic in mice gave no evidence of any identity of these with Zika virus.
We successfully detected dengue virus (DENV) genome in urine and saliva but not in plasma samples from a Japanese dengue fever patient. The results of the present study suggest that detection of DENV genome in urine and saliva can be an effective diagnostic method, particularly for children with viral hemorrhage.
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