Emerging Infectious Diseases

Insights into the structure, functional perspective, and pathogenesis of ZIKV: an updated review

Zika virus (ZIKV) poses a serious threat to the entire world. The rapid spread of ZIKV and recent outbreaks since 2007 have caused worldwide concern about the virus. Diagnosis is complicated because of the cross-reactivity of the virus with other viral antibodies. Currently, the virus is diagnosed by molecular techniques such as RT-PCR and IgM-linked enzyme immunoassays (MAC-ELISA). Recently, outbreaks and epidemics have been caused by ZIKV, and severe clinical symptoms and congenital malformations have also been associated with the virus. Although most ZIKV infections present with a subclinical or moderate flu-like course of illness, severe symptoms such as Guillain-Barre syndrome in adults and microcephaly in children of infected mothers have also been reported. Because there is no reliable cure for ZIKV and no vaccine is available, the public health response has focused primarily on preventing infection, particularly in pregnant women. A comprehensive approach is urgently needed to combat this infection and stop its spread and imminent threat. In view of this, this review aims to present the current structural and functional viewpoints, structure, etiology, clinical prognosis, and measures to prevent this transmission based on the literature and current knowledge. Moreover, we provide thorough description of the current understanding about ZIKV interaction with receptors, and a comparative examination of its similarities and differences with other viruses.

Versatile SARS-CoV-2 Reverse-Genetics Systems for the Study of Antiviral Resistance and Replication

The COVID-19 pandemic continues to threaten healthcare systems worldwide due to the limited access to vaccines, suboptimal treatment options, and the continuous emergence of new and more transmissible SARS-CoV-2 variants. Reverse-genetics studies of viral genes and mutations have proven highly valuable in advancing basic virus research, leading to the development of therapeutics. We developed a functional and highly versatile full-length SARS-CoV-2 infectious system by cloning the sequence of a COVID-19 associated virus isolate (DK-AHH1) into a bacterial artificial chromosome (BAC). Viruses recovered after RNA-transfection of in vitro transcripts into Vero E6 cells showed growth kinetics and remdesivir susceptibility similar to the DK-AHH1 virus isolate. Insertion of reporter genes, green fluorescent protein, and nanoluciferase into the ORF7 genomic region led to high levels of reporter activity, which facilitated high throughput treatment experiments. We found that putative coronavirus remdesivir resistance-associated substitutions F480L and V570L—and naturally found polymorphisms A97V, P323L, and N491S, all in nsp12—did not decrease SARS-CoV-2 susceptibility to remdesivir. A nanoluciferase reporter clone with deletion of spike (S), envelope (E), and membrane (M) proteins exhibited high levels of transient replication, was inhibited by remdesivir, and therefore could function as an efficient non-infectious subgenomic replicon system. The developed SARS-CoV-2 reverse-genetics systems, including recombinants to modify infectious viruses and non-infectious subgenomic replicons with autonomous genomic RNA replication, will permit high-throughput cell culture studies—providing fundamental understanding of basic biology of this coronavirus. We have proven the utility of the systems in rapidly introducing mutations in nsp12 and studying their effect on the efficacy of remdesivir, which is used worldwide for the treatment of COVID-19. Our system provides a platform to effectively test the antiviral activity of drugs and the phenotype of SARS-CoV-2 mutants.

Forensic public health

Deliberate dissemination of a biological agent via several different routes presents the latest challenge to global public health security. Novel pathogens and transmission methods can easily be exploited to cause disease outbreaks. Advancements in molecular biology that make it possible to genetically modify, edit, or disrupt the genome of pathogens increase the disease risk of an accidental or intentional release of pathogens with pandemic potential. The occurrence of a disease at more than an endemic level may stimulate an investigation to determine the source of the disease, who has the disease, when it occurred, and how it spreads. When intentional release of pathogens is suspected, investigators have the additional task of attributing the outbreak not only to a pathogen but also to a human source. The deliberate nature of such dissemination may be obvious. However, some forms of bioterrorism may be more covert, requiring molecular methods to uncover. The field of microbial forensics emerged following the anthrax attack in the United States in 2001 to extend epidemiologic principles to aid in the investigation of bioterrorism incidents. Microbial forensics combines epidemiology with genomic and microbiologic methods, to identify, characterize, and ascribe the cause of an incident resulting from the intentional or unintentional release of a harmful pathogen. Unlike routine epidemiologic investigations, microbial forensic investigations are undertaken when there is a potential crime due to the release of a pathogen with disease-causing potential. The investigation is conducted to attribute cause to a source based on indisputable evidence and is used to support criminal charges against the perpetrator(s). However, because bioterrorism may be unannounced, the initial investigation will start the same as to any public health incident of concern. This chapter discusses how epidemiology integrated with laboratory science can be used to identify the source of diseases caused by microorganisms or toxins—especially for attribution purposes.

Emerging Infectious Diseases

Emerging infectious diseases (EID) and reemerging infectious diseases are increasing globally. Zoonotic diseases are transmitted from animals to humans through direct contact or through food, water, and the environment. Vector-borne diseases are major sources of mortality and morbidity globally. Three mosquito-borne viruses are yellow fever, chikungunya virus, and dengue virus. Recent EIDs include Candida auris, Elizabethkingia anopheles, The Lone Star tick, and avian influenza H7N2. In addition, mcr-1 may contribute to the dissemination of drug resistance to gram-negative bacteria. Nurses play a major role in the identification and prevention of EID within health care settings.

Emergence of the East-Central-South-African genotype of Chikungunya virus in Brazil and the city of Rio de Janeiro may have occurred years before surveillance detection

Brazil, which is hyperendemic for dengue virus (DENV), has had recent Zika (ZIKV) and (CHIKV) Chikungunya virus outbreaks. Since March 2016, CHIKV is the arbovirus infection most frequently diagnosed in Rio de Janeiro. In the analysis of 1835 syndromic patients, screened by real time RT-PCR, 56.4% of the cases were attributed to CHIKV, 29.6% to ZIKV, and 14.1% to DENV-4. Sequence analyses of CHIKV from sixteen samples revealed that the East-Central-South-African (ECSA) genotype of CHIKV has been circulating in Brazil since 2013 [95% bayesian credible interval (BCI): 03/2012-10/2013], almost a year before it was detected by arbovirus surveillance program. Brazilian cases are related to Central African Republic sequences from 1980’s. To the best of our knowledge, given the available sequence published here and elsewhere, the ECSA genotype was likely introduced to Rio de Janeiro early on 2014 (02/2014; BCI: 07/2013-08/2014) through a single event, after primary circulation in the Bahia state at the Northestern Brazil in the previous year. The observation that the ECSA genotype of CHIKV was circulating undetected underscores the need for improvements in molecular methods for viral surveillance.

Detection of chikungunya virus-specific IgM on laser-cut paper-based device using pseudo-particles as capture antigen

The incidence of arbovirus infections has increased dramatically in recent decades, affecting hundreds of millions of people each year. The Togaviridae family includes the chikungunya virus (CHIKV), which is typically transmitted by Aedes mosquitoes and causes a wide range of symptoms from flu-like fever to severe arthralgia. Although conventional diagnostic tests can provide early diagnosis of CHIKV infections, access to these tests is often limited in developing countries. Consequently, there is an urgent need to develop efficient, affordable, simple, rapid, and robust diagnostic tools that can be used in point-of-care settings. Early diagnosis is crucial to improve patient management and to reduce the risk of complications. A glass-fiber laser-cut microfluidic device (paper-based analytical device [PAD]) was designed and evaluated in a proof of principle context, for the analysis of 30 µL of patient serum. Biological raw materials used for the functionalization of the PAD were first screened by MAC-ELISA (IgM capture enzyme-linked immunosorbent assay) for CHIKV Immunoglobulin M (IgM) capture and then evaluated on the PAD using various human samples. Compared with viral lysate traditionally used for chikungunya (CHIK) serology, CHIKV pseudo-particles (PPs) have proven to be powerful antigens for specific IgM capture. The PAD was able to detect CHIKV IgM in human sera in less than 10 minutes. Results obtained in patient sera showed a sensitivity of 70.6% and a specificity of around 98%. The PAD showed few cross-reactions with other tropical viral diseases. The PAD could help health workers in the early diagnosis of tropical diseases such as CHIK, which require specific management protocols in at-risk populations.

Comparative study of chikungunya Virus-Like Particles and Pseudotyped-Particles used for serological detection of specific immunoglobulin M

The incidence of chikungunya virus (CHIKV) infection has increased dramatically in recent decades. Effective diagnostic methods must be available to optimize patient management. IgM-capture Enzyme-Linked Immunosorbent Assay (MAC-ELISA) is routinely used for the detection of specific CHIKV IgM. This method requires inactivated CHIKV viral lysate (VL). The use of viral bioparticles such as Virus-Like Particles (VLPs) and Pseudotyped-Particles (PPs) could represent an alternative to VL. Bioparticles performances were established by MAC-ELISA; physico-chemical characterizations were performed by field-flow fractionation (HF5) and confirmed by electron microscopy. Non-purified PPs give a detection signal higher than for VL. Results suggested that the signal difference observed in MAC-ELISA was probably due to the intrinsic antigenic properties of particles. The use of CHIKV bioparticles such as VLPs and PPs represents an attractive alternative to VL. Compared to VL and VLPs, non-purified PPs have proven to be more powerful antigens for specific IgM capture.

Epidemiology and management practices for childhood-onset systemic lupus erythematosus patients: a survey in Latin America

To assess epidemiology and management practices of Latin America Pediatric Rheumatologists (LAPR) about childhood-onset systemic lupus erythematosus (cSLE). A cross-sectional study was performed in 288 LAPR PANLAR members based on online survey about cSLE practices. The response rate of web-based survey by LAPR was 170/288(59%) and the majority worked in university hospitals (63%). The ACR and/or SLICC classification criteria (99%) and disease activity tools (97%) were almost universally used by LAPR, whereas damage index (70%) and CHAQ (58%) instruments were less frequently used. Laboratory exams, diagnostic imaging, and biopsies were generally available (> 75%), however low availability for densitometry (66%). Drug access was excellent for the most common prescribed medications (> 75%), except for belimumab (11%). Emerging mosquito-borne diseases were also reported: dengue (20%), chikungunya (11%), and Zika (8%). Groups were further divided in two, according to the median number of cSLE patients followed by LAPR in the last year: groups A and B (≥ 25 and < 25, respectively). Frequencies of condom in combination with other contraceptive methods were significantly higher in group A than B (p = 0.01). The frequencies of reported pregnancy (p < 0.001) and non-adherence to therapy were significantly higher in group A (p = 0.023). Alcohol intake (p = 0.004) and illicit drug use (p = 0.007) were also reported more frequently by LAPR of group A in at least one cSLE patient. This first large web-based survey demonstrated an overall excellent access for diagnosis and therapy by LAPR, probably related to their high rate of practices in tertiary care of university hospitals. Adherence to therapy, pregnancy, and substance abuse was identified as major challenges in this population, particularly in larger centers.

Zika virus infection in children: epidemiology and clinical manifestations

PURPOSE

The purpose of this review is to comprehensively review Congenital Zika Syndrome in regard to their epidemiology and clinical manifestations.

METHODS

This subject review of congenital Zika syndrome was composed after conducting a thorough review of the available literature on this topic using PubMed and other primary sources.

RESULTS

The first epidemic of Zika virus infection in Brazil was followed by an unexpected sharp increase in the incidence of infants born with microcephaly and the description of a new disease, the congenital Zika syndrome. This review focuses on the epidemiological and clinical aspects of Zika infection in children. We conducted a brief historical account of the virus description in 1947, the rare cases of Zika infection occurring up to 2007, and the first epidemics in the Pacific between 2007 and 2014. We also discussed the isolation of the virus in Brazil in 2015 and its spread in the Americas, the microcephaly outbreak in Brazil and its association with Zika virus, and the current epidemiological panorama. We address the known clinical spectrum of Zika virus infection in the pediatric population, including manifestations of acute infection and congenital Zika syndrome, with emphasis on cranial, ophthalmic, and orthopedic abnormalities.

CONCLUSION

While much has been learned about congenital Zika syndrome, the full spectrum of this infection is not yet known. This review is based on current, limited data about Zika vírus infection. As more information becomes available, we will have a more accurate picture of this new disease.