Zika Virus RNA in an Asymptomatic Donor's Vitreous: Risk of Transmission?

HSV-1 and Zika Virus but Not SARS-CoV-2 Replicate in the Human Cornea and Are Restricted by Corneal Type III Interferon

Here, we report our studies of immune-mediated regulation of Zika virus (ZIKV), herpes simplex virus 1 (HSV-1), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the human cornea. We find that ZIKV can be transmitted via corneal transplantation in mice. However, in human corneal explants, we report that ZIKV does not replicate efficiently and that SARS-CoV-2 does not replicate at all. Additionally, we demonstrate that type III interferon (IFN-λ) and its receptor (IFNλR1) are expressed in the corneal epithelium. Treatment of human corneal explants with IFN-λ, and treatment of mice with IFN-λ eye drops, upregulates antiviral interferon-stimulated genes. In human corneal explants, blockade of IFNλR1 enhances replication of ZIKV and HSV-1 but not SARS-CoV-2. In addition to an antiviral role for IFNλR1 in the cornea, our results suggest that the human cornea does not support SARS-CoV-2 infection despite expression of ACE2, a SARS-CoV-2 receptor, in the human corneal epithelium.

Zika virus infection studies with CD34+ hematopoietic and megakaryocyte-erythroid progenitors, red blood cells and platelets

BACKGROUND

To date, several cases of transfusion-transmitted ZIKV infections have been confirmed. Multiple studies detected prolonged occurrence of ZIKV viral RNA in whole blood as compared to plasma samples indicating potential ZIKV interaction with hematopoietic cells. Also, infection of cells from the granulocyte/macrophage lineage has been demonstrated. Patients may develop severe thrombocytopenia, microcytic anemia, and a fatal course of disease occurred in a patient with sickle cell anemia suggesting additional interference of ZIKV with erythroid and megakaryocytic cells. Therefore, we analyzed whether ZIKV propagates in or compartmentalizes with hematopoietic progenitor, erythroid, and megakaryocytic cells.

METHODS

ZIKV RNA replication, protein translation and infectious particle formation in hematopoietic cell lines as well as primary CD34⁺ HSPCs and ex vivo differentiated erythroid and megakaryocytic cells was monitored using qRT-PCR, FACS, immunofluorescence analysis and infectivity assays. Distribution of ZIKV RNA and infectious particles in spiked red blood cell (RBC) units or platelet concentrates (PCs) was evaluated.

RESULTS

While subsets of K562 and KU812Ep6^EPO cells supported ZIKV propagation, primary CD34⁺ HSPCs, MEP cells, RBCs, and platelets were non-permissive for ZIKV infection. In spiking studies, ZIKV RNA was detectable for 7 days in all fractions of RBC units and PCs, however, ZIKV infectious particles were not associated with erythrocytes or platelets.

CONCLUSION

Viral particles from plasma or contaminating leukocytes, rather than purified CD34⁺ HSPCs or the cellular component of RBC units or PCs, present the greatest risk for transfusion-transmitted ZIKV infections.

Arboviruses (chikungunya, dengue, and Zika) associated with ophthalmic changes: a focus on aqueous fluid and vitreous humor

The aim of this study was to conduct a bibliographic survey and correlates the presence of arboviroses in the eyeball with the main eye changes presented by the population under study. This study is a systematic review of journals and indexed articles, carried out between January 2019 and June 2019, in which there was a query in the Pubmed/Medline and Scielo databases without temporal restriction. In addition to the aforementioned databases, the Brazilian Association of Organ Transplantation Association database, which provides epidemiological data on organ and tissue transplants in Brazil, was used as a research source. The Midwest region contributed to the increase in the number of organ transplants in Brazil. The number of corneal transplants in Brazil surpassed the number of organ transplants by four times. Several ophthalmic changes associated with Chikungunya, Dengue, and Zika virus infections have been diagnosed; however, few studies have identified the presence of the virus in the eyeball. Arboviruses are of great relevance to public health due to a number of factors, ranging from the diversity of infectious agents involved and the plurality of clinical manifestations because the absence of efficient laboratory support, leading to delayed disease confirmation due to lack of differential diagnostics available. Added to these difficulties is the lack of specific therapy, leaving only the symptomatic control of clinical manifestations as the only treatment option. However, the manifestations are directly associated with the decreased quality of vision and consequently the quality of life of patients.

Emerging arboviruses and implications for pediatric transplantation: A review

Recent years have brought a rise in newly emergent viral infections, primarily in the form of previously known arthropod-transmitted viruses that have increased significantly in both incidence and geographical range. Of particular note are DENV, CHIKV, and ZIKV, which are transmitted mostly by Aedes species of mosquitoes that exhibit a wide and increasing global distribution. Being important pathogens for the general population, these viruses have the potential to be devastating in the international transplant community, with graft rejection and death as possible outcomes of infection. In this review, we discuss the current state of knowledge for these viruses as well as repercussions of infection in the solid organ and HSCT population, with a focus, when possible, on pediatric patients.

Viral infections in solid organ transplant recipients: novel updates and a review of the classics

PURPOSE OF REVIEW

To summarize new discoveries in viral pathogenesis and novel therapeutic and prophylactic strategies in organ transplant recipients.

RECENT FINDINGS

For decades, prophylaxis of cytomegalovirus (CMV) has been the standard preventive strategy, but new clinical trials are expected to determine the advantages of preemptive therapy over prophylaxis. Novel anti-CMV agents, such as maribavir and letermovir, are being studied for the treatment of resistant/refractory CMV as alternatives to foscarnet and cidofovir. CMV immune monitoring may offer individualized management plans. Epstein-Barr virus infections in transplant recipients are difficult to prevent and treat, though recent data suggest possible merit to pretransplant rituximab among high-risk transplant recipients. We review the groundbreaking HIV-to-HIV organ transplant trials, which are expected to revolutionize the care of HIV-infected individuals. Finally, we review topical developments in human herpesvirus 8, Zika virus, RNA respiratory viruses, adenovirus, norovirus, and polyoma viruses in organ transplantation.

SUMMARY

Ongoing trials to optimize CMV prophylaxis and treatment, and outcomes of HIV-to-HIV organ transplantation in the United States, have significant implications to optimize management of these viruses in transplant recipients. Assessment of new antivirals and antiviral strategies, such as adoptive immunotherapy, is warranted for refractory viral infections.

Consequences of congenital Zika virus infection

The 2015 Zika virus (ZIKV) epidemic in the Americas led to the discovery that ZIKV causes congenital abnormalities including microcephaly, intrauterine growth restriction, and eye disease that can result in blindness. Studies in animal models and human organoid cultures, together with human epidemiological studies, have shown that ZIKV crosses the placenta and subsequently replicates within fetal tissues including the developing brain. Preferential infection of neural cell precursors causes damage to the developing fetal brain. However, a majority of congenitally infected humans do not develop microcephaly or other overt congenital abnormalities, so longitudinal epidemiological studies are necessary to more completely define the long-term consequences of in utero ZIKV infection.