Herpes Research Articles

Parenteral aciclovir for suspected herpes simplex virus infection in children: 0–18 years

Abstract Background Variations in neonatal aciclovir prescribing for suspected herpes simplex virus (HSV) disease are well-known, but there are limited data describing aciclovir prescribing in older children. Methods Medical records of neonates (≤28 days) and children (29 days to 18 years) prescribed intravenous aciclovir for suspected HSV disease (1 January 2019–12 December 2019) in eight Australian and New Zealand hospitals were reviewed. Prescribing indication, HSV testing, aciclovir prescription details, adverse events and discharge diagnosis were recorded. Results 1426 received empirical aciclovir. For neonates (n = 425), the median duration was 1 day (IQR 1–3), 411/425 underwent HSV investigations and 13/425 had HSV disease (two with disseminated encephalitis, four with encephalitis and seven with skin, eye, mouth disease). Of the 1001 children, 906 were immunocompetent. 136/906 suspected of mucocutaneous disease received aciclovir for a median of 2 days (1–2), 121/136 underwent HSV testing, and 69/136 had proven disease. 770/906 received aciclovir for suspected disseminated disease or encephalitis for a median of 1 day (1–2), 556/770 underwent HSV testing, and 5/770 had disseminated disease or encephalitis. Among 95 immunocompromised children, 53/58 with suspected mucocutaneous disease had HSV testing and this was confirmed in 22. Disseminated disease or encephalitis was suspected in 37/95, HSV testing conducted in 23/37 and detected in one. The median aciclovir duration was 3 (2–7) days for immunocompromised children. Nephrotoxicity occurred in 7/1426 and 24/1426 had an extravasation injury. Conclusion Frequent and often unnecessary intravenous aciclovir prescribing for suspected HSV encephalitis or disseminated disease occurred in children, as evidenced by incomplete HSV investigations and only 5/770 older children having the diagnosis confirmed.

Interest and Expectations for a Herpes Vaccine Among People Diagnosed with Genital HSV 1-2 Infection: Results from an Italian Survey

Genital herpes simplex virus (HSV) is associated with a reduction in quality of life and adverse outcomes. The aim of this study is to assess the interest and expectations for a therapeutic HSV vaccine among individuals diagnosed with genital herpes in Italy. A retrospective survey was conducted at the Infectious Diseases Unit of the IRCCS San Raffaele Scientific Institute, Milan, Italy. The study collected data on demographics, clinical history and interest in HSV vaccination. The results showed that 87.5% of participants were interested in a therapeutic vaccine, with interest higher among younger people and those with frequent genital herpes recurrences. Participants most expected the vaccine to reduce the pain associated with outbreaks, followed by a reduction in the frequency and duration of recurrences. These findings underscore the strong demand for a therapeutic HSV vaccine, especially among those who experience recurrent outbreaks, and highlight the importance of considering patient expectations when developing preventive and therapeutic strategies for genital herpes.

A clinical case of skin lymphocytoma in a young woman

A 25-year-old woman came to consult a dermatovenerologist. The woman complained of a rapidly progressing painless lump on the right wing of her nose which developed after photo-rejuvenation treatment and the development of herpetic infection.in the place of a previous lipoma removed by radio wave surgery. The clinical picture was characterized by a solitary disc-shaped plaque, 2 cm in size, bluish-reddish-brownish in color, of a doughy consistency, significantly protruding above the skin surface, with clear borders and a smooth, shiny surface. There was a complex differential diagnostics, the final diagnosis was confirmed by the results of a histological examination, which revealed changes characteristic of lymphocytoma. The patient was treated with aminoquinoline preparations and topical glucocorticosteroids and rapid positive dynamics with complete regression of the skin pathological process was observed. A clinical case of skin lymphocytoma that occurred after several successive trigger factors such as lipoma formation and removal, photo rejuvenation procedures, and herpes infection is presented in the article. This is a fairly rare disease that does not have a pathognomonic clinical picture, so it is difficult to differentiate and diagnose it. The results of a pathomorphological examination are essential for the diagnosis. A positive effect with a complete regression of skin changes can quickly occur if treated correctly.

NET-EN treatment leads to delayed HSV-2 infection, enhanced mucin and T cell functions in the female genital tract when compared to DMPA in a preclinical mouse model

Depot-medroxyprogesterone acetate (DMPA) and Norethisterone Enanthate (NET-EN) are progestin-only injectable contraceptives widely used by women in sub-Sharan Africa, where incidence of HIV-1 and HSV-2 infection remains high. Studies indicate that DMPA usage can increase the risk of HSV-2 infection, but limited data indicate no increased risk with use of NET-EN. We therefore investigated the effects of NET-EN and DMPA on susceptibility to vaginal HSV-2 infection in ovariectomized (OVX) mice and effects on immune responses, particularly in the vaginal tract (VT). OVX mice, when treated with NET-EN and infected intravaginally, had delayed genital pathology, decreased viral shedding, and extended survival compared to DMPA- or untreated OVX mice. CD4+ T cells isolated from VT showed no significant change in frequency with either contraceptive. However, DMPA significantly decreased the total number of VT CD4+ and CD8+ T cells and the number of IFN-γ producing CD4 and CD8 T cells and increased the percentage of CD4 and CD8 T cells producing TNF-α compared to untreated mice. In contrast, NET-EN significantly enhanced percentages of CD8+ T cells compared to DMPA treated mice, and frequencies of IFN-γ+ CD4 and CD8 T cells in the VT compared to untreated mice. Comparative analysis of splenic lymphocytes indicated that DMPA treatment resulted in reduction of CD4+ T cell frequency, but enhanced TNF-α+ CD4 T cells compared to untreated mice. NET-EN enhanced the frequency of CD8 T cells, as well as IFN-γ+ and TNF-α+ CD4, and IFN-γ+ CD8 T cells in the spleen compared to untreated mice. Importantly, we found DMPA treatment that significantly reduced mucin production, whereas NET-EN enhanced expression of cell-associated mucin in VT. High levels of mucin in NET-EN mice were associated with lower levels of HSV-2 virus detected in the vaginal tract. This study provides the first evidence that NET-EN treatment can delay HSV-2 infection compared to DMPA.

Disseminated herpes simplex virus infection in pregnancy

Herpes simplex virus (HSV) types 1 and 2 produce the most common sexually transmitted infection in women, with a higher incidence reported in developing countries. When the first infection occurs during the perinatal period, it can spread, resulting in high morbidity and mortality of the mother and child, in addition to mainly neurological sequelae in the newborn. Despite having reliable laboratory tests, the diagnosis of herpes simplex virus infection in this population is complex since the clinical presentation ranges from asymptomatic or with non-specific symptoms without lesions on the skin or mucous membranes. For this reason, a high clinical suspicion is necessary. Here, we present the case of a mother with disseminated herpes simplex virus type 2 infection with viral hepatitis and fetal death, highlighting the importance of suspecting the diagnosis in febrile women with systemic compromise during the perinatal period, even in the absence of rash.

Next-generation 3D printed multipurpose prevention intravaginal ring for prevention of HIV, HSV-2, and unintended pregnancy

Globally, nearly half of all pregnancies are unintended, ~1.3 million new human immunodeficiency virus (HIV) infections are reported every year, and more than 500 million people are estimated to have a genital herpes simplex virus (HSV-2) infection. Here we report the first 3D printed multipurpose prevention technology (MPT) intravaginal ring (IVR) for prevention of HIV, HSV-2, and unintended pregnancy. The IVRs were fabricated using state-of-the-art Continuous Liquid Interface Production (CLIP™) 3D printing technology using a biocompatible silicone-urethane based resin. Anti-HIV drug (Dapivirine, DPV), anti-herpes drug (Pritelivir, PTV) and a contraceptive drug (Levonorgestrel, LNG) were loaded in a macaque size IVR (25 mm outer diameter, OD; 6.0 mm cross-section, CS) allometrically scaled from the human size (54 mm OD; 7.6 mm CS) IVR analogue. All three active pharmaceutical ingredients (APIs) were loaded in the IVR using a single-step drug loading process driven by absorption. DPV, PTV, and LNG elicited zero-order release kinetics in vitro in simulated vaginal fluid (SVF) at pH 4 and pH 8 relevant to human and macaque vaginal pH respectively. CLIP 3D printed MPT IVRs remained stable after 6 months of storage at 4 °C with no change in physical, dimensional, or mechanical properties and no change in drug concentration and absence of drug degradation byproducts. The MPT IVRs elicited sustained release of all three APIs in macaques for 28 days with median plasma concentrations of 138 pg/mL (DPV), 18,700 pg/mL (PTV), and 335 pg/mL (LNG). Safety studies demonstrated that the MPT IVRs were safe and well tolerated in the macaques with no observed change or abnormalities in vaginal pH and no significant changes in any of the 22 mucosal cytokines and chemokines tested including pro-inflammatory (IL-1β, IL-6, IL-8, IFN-γ, TNF-α, IL-17, IL-18) and anti-inflammatory (IL-10, IL-12) cytokines while the MPT IVR was in place or after its removal. Additionally, MPT IVRs elicited no observed alterations in systemic CD4+ and CD8+ T cells during the entire study. Collectively, the proposed MPT IVR has potential to expand preventative choices for young women and girls against unintended pregnancy against two highly prevalent sexually transmitted infections (STIs).

Impact of Tobacco Use on Herpes Simplex Virus Infections: Findings From a National Survey.

Herpes simplex virus (HSV) infections, primarily caused by HSV-1 and HSV-2, are prevalent worldwide and carry significant health implications. The impact of tobacco use on HSV infections, however, remains underexplored. This cross-sectional study utilized the National Health and Nutrition Examination Survey (NHANES) database (2009-2016) to investigate the link between Tobacco use and HSV infections among U.S. adults. Smoking status, volume, and serum cotinine levels were analyzed, alongside demographic and behavioral factors. Propensity score matching (PSM) was employed to adjust for confounders such as sexual behavior. Our study involved 5693 participants to explore the relationship between tobacco use and HSV infection. We found that smokers, particularly current smokers, have a significantly increased risk of both HSV-1 and HSV-2 infections compared to non-smokers. Specifically, the adjusted odds ratio (OR) for HSV-1 in current smokers was 1.36 (95% CI: 1.16-1.59, p < 0.001), and for HSV-2, it was 2.37 (95% CI: 1.88-3, p < 0.001). The risk escalates with the intensity of smoking. Elevated serum cotinine levels correlated with an increased risk of HSV infection (HSV-1:1.13 [95% CI:1.09-1.18, p < 0.001]; HSV-2:1.33 [95% CI:1.25-1.41, p < 0.001]). After PSM for factors such as age, gender, sexual behavior, and condom use, these associations remained significant. Tobacco use is significantly associated with an increased risk of HSV infections, highlighting the importance of reducing tobacco exposure in public health strategies against HSV. Further, longitudinal studies are warranted to establish causality and explore underlying mechanisms.

Molecular Biology for Diagnosis of Congenital and Neonatal Infections in the Cerebrospinal Fluid of Newborns from a Brazilian Tertiary Hospital

The risk of infection transmission from mother to fetus depends on the pathogen. TORCH agents cause some neuroinfections, including Toxoplasmosis, rubella, Cytomegalovirus, herpes simplex 1 and 2, and others (Varicella Zoster, Parvovirus B-19, Epstein–Barr virus, and Zika virus). The consequences can be stillbirth, prematurity, uterine growth restriction, and congenital malformations. The detection of DNA/RNA from CSF by molecular methods is a marker of the involvement of congenital infection in the central nervous system. This study aimed to identify the frequency of these pathogens in CSF samples from newborns (1 to 28 days old) at a tertiary hospital, using PCR, and determine the clinical consequences. Methods: This was a prospective descriptive study involving the molecular analysis of 151 CSF samples from neonates, collected for cytological and biochemical diagnosis from 2017 to 2021. After the results and consent from the participants’ caregivers were obtained, the leftover material was sent to the University’s Virology Laboratory and submitted for DNA/RNA extraction and Nested-PCR/RT-PCR. A review of the patients’ medical records and descriptive statistics was performed. This work was approved by the Ethics Committee (CAAE: 86760218.3.0000.5404). Results: A total of 151 CSF samples were obtained, 16 of which were positive (10.6% [95% CI%: 6.18–16.63%]). Two of these were PCR-positive for HSV-1 (1.3%), four for VZV (2.6%), one for CMV (0.67%), two for Toxoplasmosis (1.3%), four for Parvovirus B-19 (2.6%), and four for Zika (2.6%). The proportion of positive PCR results was higher in the group that presented with malformations (25.0% vs. 8.4%, p = 0.040). Conclusions: The pathogens identified by PCR were mostly Zika virus, VZV, and B-19, and these were mainly found in newborns with malformations.

Coinfection of Toxoplasma gondii and Other Microorganisms: A Systematic Review and Meta-Analysis.

Toxoplasmosis is a disease caused by the intracellular protozoan Toxoplasma gondii, which has infected a third of the global population. Immunocompromised individuals and children with congenital disorders are most likely to be impacted by toxoplasmosis, and accurate diagnosis is essential. Toxoplasmosis is associated with HIV, schizophrenia, and diabetes. However, few studies have analyzed the association with other microorganisms. The purpose of this study was to determine the prevalence of coinfection of Toxoplasma gondii with other pathogens. From November 1997 to June 2024, PubMed, Science Direct, LAT index, Web of Science, Google Scholar, and Research Gate were searched. The keywords used were "Toxoplasma and microorganism coinfection", "Toxoplasma coinfection and parasites", "Toxoplasma coinfection and Protozoans or Bacteria or Helminths or Nematodes or Trematodes or Mycobacterium", "Toxoplasma gondii in coinfection with virus", and "Human Toxoplasmosis and coinfection". Next, OpenMeta Analyst Software version 12.11 was used for meta-analysis, creating forest plots, and determining heterogeneity I2. A total of 17,535 patients in 48 articles, of whom 5848 were seropositive to T. gondii, were included in this review. Population studies showed that the prevalence of virus infection was most frequent (32%), followed by parasites (18.4%), bacteria (29.7%), and fungi (5.8%). The pooled prevalence of coinfection was found to be 29.1%, with a lower bound of 0.232, an upper bound of 0.350, a standard error of 0.030, and p < 0.001. Heterogeneity (I2) was 99.12%, p < 0.001, with a global variance tau2 = 0.042. Toxoplasma gondii is an opportunist that mainly affects immunocompromised populations. The main coinfections were found to be viral infections, with HIV ranking first, followed by cytomegalovirus, hepatitis B and C, rubella, herpes simplex 1 and 2, SARS-CoV-2, and coxsackie virus.

Lytic promoter activity during herpes simplex virus latency is dependent on genome location.

Herpes simplex virus 1 (HSV-1) is a significant pathogen that establishes lifelong latent infections with intermittent episodes of resumed disease. In mouse models of HSV infection, sporadic low-level lytic gene expression has been detected during latency in the absence of reactivation events that lead to production of new viruses. This viral activity during latency has been reported using a sensitive Cre-marking model for several lytic gene promoters placed in one location in the HSV-1 genome. Here, we extend these findings in the same model by examining first, the activity of an ectopic lytic gene promoter in several places in the genome and second, whether any promoters might be active in their natural context. We found that Cre expression was detected during latency from ectopic and native promoters, but only in locations near the ends of the unique long genome segment. This location is significant because it is in close proximity to the region from which latency-associated transcripts (LATs) are derived. These results show that native HSV-1 lytic gene promoters can produce protein products during latency, but that this activity is only detectable when they are located close to the LAT locus.IMPORTANCEHSV is a significant human pathogen and the best studied model of mammalian virus latency. Traditionally, the active (lytic) and inactive (latent) phases of infection were considered to be distinct, but the notion of latency being entirely quiescent is evolving due to the detection of some lytic gene expression during latency. Here, we add to this literature by finding that the activity can be found for native lytic gene promoters as well as for constructs placed ectopically in the HSV genome. However, this activity was only detectable when these promoters were located close by a region known to be transcriptionally active during latency. These data have implications for our understanding of HSV gene regulation during latency and the extent to which transcriptionally active regions are insulated from adjacent parts of the viral genome.

Higher dose antiviral therapy for herpes infections is associated with a risk of serious adverse events in older adults with chronic kidney disease.

Antiviral use has been linked to encephalopathy and elevated serum creatinine concentrations in individuals with chronic kidney disease (CKD) in case reports. Using linked healthcare data in Ontario, we conducted a population-based cohort study on adults aged ≥66 years not receiving dialysis and newly prescribed oral acyclovir, valacyclovir, or famciclovir in the outpatient setting (2008-2022) at higher versus lower doses. The primary composite outcome, a hospital visit with encephalopathy or acute kidney injury (AKI) within 14 days of initiating antiviral treatment, was examined in a primary cohort. AKI was assessed in a secondary cohort of older adults with CKD with available linked hospital-based laboratory (lab) data. We used inverse probability of treatment weighting on the propensity score to balance comparison groups on baseline health. Weighted risk ratios (RR) and risk differences (RD) were obtained using modified Poisson and binomial regression. In the primary cohort, higher- versus lower-dose antiviral was not associated with an increased 14-day risk of hospital visit with encephalopathy or AKI. However, Higher- versus lower-dose antiviral was associated with a higher risk of a hospital visit with AKI when assessed using lab values (weighted number of events, 70 of 8407 [0.83%] versus 18 of 8230 [0.22%], respectively; weighted RR, 3.83 [95% CI, 1.87-7.87]; weighted RD, 0.62% [95% CI, 0.37%-0.86%]). In older adults with CKD, starting an antiviral at a higher versus lower dose was associated with a higher risk of AKI, although the absolute risk of this event was <1%.

Out-of-Hospital Infant Mortality Associated with Herpesviruses

Introduction. Infant mortality is a universally recognized indicator for social well-being of the population. There is a need for an in-depth analysis of the causes and factors leading to the death of infants at home, including determining the etiology of infectious diseases potentially causing death.The purpose of the study — to determine the implication of herpesviruses in infant out-of-hospital death.Materials and methods. Samples from autopsy material of 23 infants (blood, small intestine, heart, lungs, liver, brain), who died at home from various causes, were analyzed by PCR for the presence of viral DNA and RNA from herpesviruses, orthomyxoviruses, paramyxoviruses, picornaviruses, adenoviruses, coronaviruses, parvoviruses, as well as intestinal viruses.Results and discussion. Positive PCR results were found in 11 cases (43.5 %), of which herpesviruses DNA was detected in 10 cases. In these samples, cytomegalovirus predominated, in association with Epstein — Barr virus and human herpesvirus type 6. This association was detected in blood and internal organs samples from four infants diagnosed with generalized viral infection, and from two infants with acute respiratory viral infection. This suggests the presence of a causal relationship between the lethal outcome and the detection of these viruses. Not all infants showed clinical signs characteristic of generalized herpes infection. In one infant with hypertrophic cardiomyopathy, coronavirus, enterovirus and rotavirus DNA was found in samples of internal organs.Conclusion. Results showed the dominant role of the herpesviruses in out-of-hospital infant death cases.

Seroprevalence of herpes simplex virus 2 infection among commercial sex workers in Colombo, Sri Lanka

Background: Herpes Simplex Virus Type 2 (HSV2) causes genital herpes, an incurable, lifelong sexually transmitted infection (STI). This study was conducted to describe the seroprevalence and associated factors of HSV2 infection in a cohort of Female Sex Workers (FSWs). Methods: A descriptive cross-sectional study was conducted on 136 FSWs who attended the central STD Clinic, in Colombo. They were assessed using an interviewer-administered questionnaire followed by serum sampling. Serum samples were tested for HSV2 IgG using an enzyme immunoassay specific for glycoprotein gG2 of HSV2. Results: HSV2 seroprevalence of FSW was 66.9% (91/136) of which only 14.3% (13/91) reported a history of genital infection. Age ≥35 years (OR 3.35, 95%CI 1.54-7.31, p=0.002), education ≥ grade 5 (OR 8.35, 95%CI 13.1- 64.7, p&lt;0.001), lifetime sexual partners ≥ 200 (OR 5.33, 95% CI 2.3-12.36), p&lt;0.001), duration of sex work ≥1 year (OR 4.5, 95% CI 2.09-9.65, p&lt;0.001) and history of STI (OR 4.52, 95% CI 1.9-10.78, p&lt;0.001) were statistically significant risk factors for high HSV2 prevalence. Consistent condom use by commercial partners in the last 3 months was not a significant protective factor in preventing HSV2 infection (OR 0.44, 95% CI 0.15-1.26, p = 0.12) in this cohort. Conclusions: The seroprevalence of HSV2 is high in this population and most of them did not report any genital infection. Multiple risk factors for higher prevalence were observed. Findings support the need for regular surveillance, monitoring of HSV-2 infection in high-risk populations, and expanding awareness of HSV-2 infection in the country.

Phytochemistry, Mechanisms, and Preclinical Studies of Echinacea Extracts in Modulating Immune Responses to Bacterial and Viral Infections: A Comprehensive Review.

Echinacea species, particularly Echinacea purpurea, Echinacea angustifolia, and Echinacea pallida, are renowned for their immunomodulatory, antibacterial, and antiviral properties. This review explores the mechanisms by which echinacea herbal extracts modulate immune responses, focusing on their effects on both innate and adaptive immunity in bacterial and viral infections. Key bioactive compounds, such as alkamides, caffeic acid derivatives, flavonoids, and polysaccharides, contribute to these effects. These compounds enhance immune cell activity, including macrophages and natural killer cells, stimulating cytokine production and phagocytosis. The antibacterial activity of echinacea against respiratory pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Legionella pneumophila) and skin pathogens (Staphylococcus aureus, Propionibacterium acnes) is reviewed, as well as its antiviral efficacy against viruses like herpes simplex, influenza, and rhinovirus. Echinacea's potential as a complementary treatment alongside conventional antibiotics and antivirals is discussed, particularly in the context of antibiotic resistance and emerging viral threats. Challenges associated with variability in phytochemical content and the need for standardized extraction processes are also addressed. This review provides a comprehensive overview of echinacea's therapeutic potential and outlines future directions for research, including clinical trials and dosage optimization.

A fur plucking model to study herpes simplex virus reactivation and recurrent disease.

Herpes simplex viruses (HSV-1 and HSV-2) have infected over half of the US adult population to cause a lifelong, persistent infection; however, our understanding of the mechanisms that govern HSV reactivation and recurrent disease is incomplete. This is in part due to limitations in the animal models used to study recurrent disease, which are laborious and inefficient in mice. To address this technical gap, we developed a mouse model in which fur plucking after flank skin infection is sufficient to induce episodes of HSV reactivation and recurrent disease. Our work provides a model for the field to investigate the pathogenic mechanisms of HSV and immune responses during recurrent disease and provides an opportunity to investigate the neurobiology of HSV infection.

The TET3 inflammasome senses unique long HSV-1 proteins for virus particle budding from the nucleus.

Inflammasomes play important roles in resisting infections caused by various pathogens. HSV-1 is a highly contagious virus among humans. The process by which HSV-1 particles bud from the nucleus is unique to herpes viruses, but the specific mechanism is still unclear. Here, we screened genes involved in HSV-1 replication. We found that TET3 plays an essential role in HSV-1 infection. TET3 recognizes the UL proteins of HSV-1 and, upon activation, can directly bind to caspase-1 to activate an ASC-independent inflammasome in the nucleus. The subsequent cleavage of GSDMD in the nucleus is crucial for the budding of HSV-1 particles from the nucleus. Inhibiting the perforation ability of GSDMD on the nuclear membrane can significantly reduce the maturation and spread of HSV-1. Our results may provide a new approach for the treatment of HSV-1 in the future.

Global, Regional, and National Trends Analysis in Incidence of Genital Herpes Among the Population Aged 15-49 Years - Worldwide, 1990-2021.

Genital herpes infection is a chronic condition that can cause recurrent symptoms, significantly affecting both quality of life and sexual relationships. However, there is currently no available data on the global trends and regional variations in the incidence of genital herpes among individuals of reproductive age. From 1990 to 2021, there was a 51.97% increase in global incident cases of genital herpes among individuals aged 15-49 years. The incidence rates also rose in low-middle socio-demographic index region, South Asia, Southern Sub-Saharan Africa, and Central Europe. Among these regions, countries in Southern Sub-Saharan Africa experienced the highest burden of genital herpes among individuals aged 15-49 years. Given the rise in global incident cases and incidence rates in some regions among individuals of reproductive age from 1990 to 2021, it is imperative to prioritize the implementation of preventive strategies and interventions for genital herpes infection. This includes a significant focus on the development of vaccines.

Newborns with microcephaly in Brazil and potential vertical transmission of Oropouche virus: a case series

Oropouche fever, an orthobunyavirus disease endemic in Brazilian Amazon, has caused many febrile epidemics. In 2024, an epidemic of Oropouche fever spread in Brazil, with more than 7930 cases reported between Jan 1 and Aug 31. Infections in pregnant people have suggested the possibility of negative fetal consequences, therefore we tested newborns with microcephaly for known congenital pathogens and Oropouche virus (OROV). In this case series, we assessed historical cases of infants born with microcephaly, arthrogryposis, and other congenital malformations without a confirmed cause and their mothers for potential OROV congenital infections. The study population consisted of infants born in Brazil with samples from 2015-21 and 2024. Serum and cerebrospinal fluid (CSF) from this case series were analysed for: syphilis, toxoplasmosis, rubella, cytomegalovirus, herpes simplex, HIV, Zika, dengue, and chikungunya. Individuals that were negative for these pathogens were then tested for OROV. Pathogen testing included ELISA and haemagglutination inhibition testing for antibodies and RT-PCR for virus RNA. We tested 68 samples from 65 historical cases of congential malformations and three cases from 2024. All cases were from ten states in Brazil. Three historical cases tested positive for OROV and 62 historical cases tested negative. The three cases from 2024 all tested positive for OROV. Of the positive cases, five were female and one was male. Not all pathogens were tested for each case, and some did not have maternal samples available. One of the newborns (case 6) died aged 47 days and tissue samples were tested by real-time RT-PCR, histopathology, and immunohistochemistry assays. One other newborn died in 2016 but no post-mortem samples were available. OROV IgM was detected in five of five newborn CSF samples, and five of five newborn serum samples. Four of five maternal serum samples were positive for OROV IgM. One of four newborn CSF samples (case 6 at age 44 days) was OROV positive by real-time RT-quantitative PCR and 0 of four newborn serum samples were positive, as were 0 of three maternal serum samples. Case 6 had major tissue changes of the brain macroscopically and microscopically, including necrotic and apoptotic changes of neurons, microglia and astrocytes, vacuolisation, and tissue atrophy. OROV RNA was detected in brain, lungs, kidney, CSF, and pleural fluid; OROV antigens were found in CNS, liver, kidney, heart, and lung, mainly in neurons and microglia and also in endothelial cells, suggesting vasculitis. We detected OROV IgM in six of 68 newborns with microcephaly of unknown cause. One infant who died had OROV RNA and antigen in several tissues, including the brain. The possibility of OROV vertical transmission and potential fetal harm must be investigated with urgency. The evidence presented here does not completely confirm vertical transmission or congenital malformations due to OROV, but thorough case finding and detailed investigation of maternal or fetal OROV infection is a priority. Evandro Chagas Institute, Secretaria de Vigilância em Saúde e Ambiente, and Ministry of Health and National Institute of Science and Technology for Emerging and Reemerging Viruses.

Single-cell RNA Sequencing Reveals the Diversity of the Immunological Landscape Response to Genital Herpes

Genital herpes (GH) is a common sexually transmitted disease, which is primarily caused by herpes simplex virus type 2 (HSV-2), and continues to be a global health concern. Although our understanding of the alterations in immune cell populations and immunomodulation in GH patients is still limited, it is evident that systemic intrinsic immunity, innate immunity, and adaptive immunity play crucial roles during HSV-2 infection and GH reactivation. To investigate the mechanisms underlying HSV-2 infection and recurrence, single-cell RNA sequencing (scRNA-seq) was performed on immune cells isolated from the peripheral blood of both healthy individuals and patients with recurrent GH. Furthermore, the systemic immune response in patients with recurrent GH showed activation of classical monocytes, CD4+ T cells, natural killer cells (NK cells), and plasmacytoid dendritic cells (pDCs), especially of genes associated with the Toll-like receptor signaling pathway and T cell activation. Circulating immune cells in GH patients show higher expression of genes associated with inflammation and antiviral responses both in the scRNA-Seq data set and in independent quantitative real-time polymerase chain reaction (qRT-PCR) analysis and ELISA experiments. This study demonstrated that localized genital herpes, resulting from HSV reactivation, may influence the functionality of circulating immune cells, suggesting a potential avenue for future research into the role of systemic immunity during HSV infection and recurrence.

Novel Mouse Model of Recurrent Sublethal Herpes Simplex Virus Infection Recapitulates Human Antibody Responses to Primary and Chronic Infection.

Background: Herpes simplex virus (HSV) vaccine development has been impeded by the absence of predictive preclinical models and defined correlates of immune protection. Prior candidates elicited neutralizing responses greater than natural infection but no antibody-dependent cellular cytotoxicity (ADCC) and failed to protect in clinical trials. Primary HSV infection also elicits only neutralizing responses, but ADCC and an expanded antigenic repertoire emerge over time. This evolution may contribute to the decreased frequency and severity of recurrences. To test this notion, we developed a recurrent HSV infection mouse model and evaluated changes in humoral immunity with repeated challenges. Methods: Mice were repeatedly infected intranasally with clinical isolates of HSV-1 or HSV-2 for four months. HSV binding IgG, neutralizing (with or without complement) and ADCC-mediating antibodies were quantified prior to each round of infection. Viral targets were assessed by western blotting. Pooled immune serum (750 μg IgG per mouse) was passively transferred into naïve wild-type or Hvem knockout mice 24 h prior to lethal skin challenge. Results: Repeated exposure to HSV-1 or HSV-2 induced an increase in total HSV-binding IgG but did not boost neutralizing titers. In contrast, ADCC-mediating responses increased significantly from the first to the fourth viral exposure (p < 0.01). The increase was associated with an expanded antigenic repertoire. Passive transfer of fourth round immune serum provided significant protection whereas first round serum failed to protect (p < 0.01). However, protection was lost when serum was transferred into Hvem knockout mice, which are impaired in mediating ADCC killing. Conclusion: This novel model recapitulates clinical responses, highlights the importance of ADCC in protecting against recurrent infection, and provides a strategy for evaluating therapeutic vaccines.