Virus and host-specific differences in oral human herpesvirus shedding kinetics among Ugandan women and children

Spatial kinetics and immune control of murine cytomegalovirus infection in the salivary glands

Human cytomegalovirus (HCMV) is the most common congenital infection. Several HCMV vaccines are in development, but none have yet been approved. An understanding of the kinetics of CMV replication and transmission may inform the rational design of vaccines to prevent this infection. The salivary glands (SG) are an important site of sustained CMV replication following primary infection and during viral reactivation from latency. As such, the strength of the immune response in the SG likely influences viral dissemination within and between hosts. To study the relationship between the immune response and viral replication in the SG, and viral dissemination from the SG to other tissues, mice were infected with low doses of murine CMV (MCMV). Following intra-SG inoculation, we characterized the viral and immunological dynamics in the SG, blood, and spleen, and identified organ-specific immune correlates of protection. Using these data, we constructed compartmental mathematical models of MCMV infection. Model fitting to data and analysis indicate the importance of cellular immune responses in different organs and point to a threshold of infection within the SG necessary for the establishment and spread of infection.

Detection of Felis catus Gammaherpesvirus 1 in Domestic Cat Saliva: Prevalence, Risk Factors, and Attempted Virus Isolation

Felis catus gammaherpesvirus 1 (FcaGHV1) infects domestic cats worldwide, yet it has not been successfully propagated in cell culture, and little is known about how it is shed and transmitted. To investigate the salivary shedding of FcaGHV1, we quantified FcaGHV1 DNA in feline saliva by qPCR. For FcaGHV1-positive saliva, we sequenced a portion of the viral glycoprotein B (gB) gene and attempted to isolate the infectious virus by passage in several felid and non-felid cell lines. We detected FcaGHV1 DNA in 45/227 (19.8%) saliva samples with variable viral DNA loads from less than 100 to greater than 3 million copies/mL (median 4884 copies/mL). Multiple saliva samples collected from an infected cat over a two-month period were consistently positive, indicating that chronic shedding can occur for at least two months. Cat age, sex, and health status were not associated with shedding prevalence or viral DNA load in saliva. Feral status was also not associated with shedding prevalence. However, feral cats had significantly higher FcaGHV1 DNA load than non-feral cats. Sequencing of FcaGHV1 gB showed low sequence diversity and >99.5% nucleotide identity to the worldwide consensus FcaGHV1 gB sequence. We did not detect virus replication during the passage of FcaGHV1-positive saliva in cell culture, as indicated by consistently negative qPCR on cell lysate and supernatant. To our knowledge, these data show for the first time that cats in Canada are infected with FcaGHV1. The data further suggest that shedding of FcaGHV1 in saliva is common, can occur chronically over an extended period of time, and may occur at higher levels in feral compared to non-feral cats.

Increased frequency and quantity of mucosal and plasma cytomegalovirus replication among Ugandan Adults Living with HIV

BACKGROUND

Co-infection with HIV can result in impaired control of cytomegalovirus (CMV) replication, increasing the likelihood of disease and onward transmission. The objective of this analysis was to measure the impact of HIV on CMV replication in an intensively-sampled cohort in Kampala, Uganda.

METHODS

CMV seropositive men and women aged 18-65, with or without HIV co-infection, were followed for one month. Daily oral swabs and weekly anogenital swabs and plasma were collected. Quantitative CMV PCR was performed on all samples.

RESULTS

Eighty-five participants were enrolled and provided ≥1 oral swab; 43 (51%) were HIV-seropositive. People living with HIV (PLWH; median CD4 count 439 cells/mm3; none on antiretrovirals) had 2-4 times greater risk of CMV detection at each anatomical site assessed. At the oral site, 773 of 1272 (61%) of samples from PLWH had CMV detected, compared to 214 of 1349 (16%) among people without HIV. Similarly, the mean CMV quantity was higher among PLWH at all anatomical sites, with the largest difference seen for oral swabs (mean difference 1.63 log/mL; 95% CI 1.13-2.13). Among PLWH, absolute quantity of CD4+ T-cells was not associated with risk of CMV detection. HIV plasma RNA quantity was positively correlated with oral CMV shedding frequency, but not detection at other sites.

CONCLUSIONS

Mucosal and systemic CMV replication occurs at higher levels in PLWH than people without HIV, particularly oral shedding, which is a major mode of CMV transmission. Increased CMV replication despite relatively preserved CD4+ T-cell counts suggests that additional interventions are required to improve CMV control in PLWH.

Molecular Pathogenesis of Human Immunodeficiency Virus-Associated Disease of Oropharyngeal Mucosal Epithelium

The oropharyngeal mucosal epithelia have a polarized organization, which is critical for maintaining a highly efficient barrier as well as innate immune functions. In human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) disease, the barrier and innate immune functions of the oral mucosa are impaired via a number of mechanisms. The goal of this review was to discuss the molecular mechanisms of HIV/AIDS-associated changes in the oropharyngeal mucosa and their role in promoting HIV transmission and disease pathogenesis, notably the development of opportunistic infections, including human cytomegalovirus, herpes simplex virus, and Epstein-Barr virus. In addition, the significance of adult and newborn/infant oral mucosa in HIV resistance and transmission was analyzed. HIV/AIDS-associated changes in the oropharyngeal mucosal epithelium and their role in promoting human papillomavirus-positive and negative neoplastic malignancy are also discussed.

Maternal HIV Infection as a Risk Factor for Primary Epstein-Barr Virus Infection in Kenyan Infants

Human immunodeficiency virus (HIV) infection is known to be associated with EBV shedding in saliva suggesting an increased risk of EBV transmission to infants born to mothers with HIV at an earlier age. In this study we investigated (i) whether maternal HIV status was a risk factor for EBV in blood at delivery or for shedding in saliva and breast milk of 6- and 10-weeks post-partum mothers, (ii) if there was a difference in EBV strains shed between HIV+ and HIV- mothers, and (iii) if maternal HIV status was a determinant of EBV viral load in their infants. Samples were collected as part of a prospective cohort study that followed HIV-positive (HIV+) and HIV-negative (HIV-) pregnant women in Western Kenya through delivery and post-partum period. EBV viral load in blood was found to be significantly higher in mothers with HIV (p-value = 0.04). Additionally, a statistically significant difference was observed between EBV viral load in saliva samples and HIV status where HIV+ mothers had a higher EBV viral load in saliva at 6-weeks post-partum compared to HIV- mothers (p-value < 0.01). The difference in EBV shedding in breast milk was not found to be statistically significant. Furthermore, no difference in frequency of EBV strain was attributable to HIV- or HIV+ mothers. Interestingly, we found that infants born to HIV+ mothers had a higher EBV viral load at the time of their first EBV detection in blood than infants born to HIV- mothers and this was independent of age at detection. Overall, our study suggests that HIV infected mothers shed more virus in saliva than HIV-negative mothers and infants born to HIV+ mothers were at risk for loss of control of primary EBV infection as evidenced by higher EBV viral load following primary infection.

Salivary DNA Loads for Human Herpesviruses 6 and 7 Are Correlated With Disease Phenotype in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex chronic condition affecting multiple body systems, with unknown cause, unclear pathogenesis mechanisms, and fluctuating symptoms which may lead to severe debilitation. It is frequently reported to have been triggered by an infection, but there are no clear differences in exposure to, or seroprevalence of, any particular viruses between people with ME/CFS and healthy individuals. However, herpes viruses have been repeatedly hypothesized to underlie the chronic relapsing/remitting form of MS/CFS due to their persistence in a latent form with periodic reactivation. It is possible that ME/CFS is associated with herpes virus reactivation, which has not been detectable previously due to insufficiently sensitive testing methods. Saliva samples were collected from 30 people living with ME/CFS at monthly intervals for 6 months and at times when they experienced symptom exacerbation, as well as from 14 healthy control individuals. The viral DNA load of the nine humanherpes viruses was determined by digital droplet PCR. Symptoms were assessed by questionnaire at each time point. Human herpesvirus (HHV) 6B, HHV-7, herpes simplex virus 1 and Epstein-Barr virus were detectable within the saliva samples, with higher HHV-6B and HHV-7 viral loads detected in people with ME/CFS than in healthy controls. Participants with ME/CFS could be broadly separated into two groups: one group displayed fluctuating patterns of herpesviruses detectable across the 6 months while the second group displayed more stable viral presentation. In the first group, there was positive correlation between HHV-6B and HHV-7 viral load and severity of symptom scores, including pain, neurocognition, and autonomic dysfunction. The results indicate that fluctuating viral DNA load correlates with ME/CFS symptoms: this is in accordance with the hypothesis that pathogenesis is related to herpesvirus reactivation state, and this should be formally tested. Herpesvirus reactivation might be a cause or consequence of dysregulated immune function seen in ME/CFS. The sampling strategy and molecular tools developed here permit such large-scale epidemiological investigations.

Examining the dynamics of Epstein-Barr virus shedding in the tonsils and the impact of HIV-1 coinfection on daily saliva viral loads

Epstein-Barr virus (EBV) is transmitted by saliva and is a major cause of cancer, particularly in people living with HIV/AIDS. Here, we describe the frequency and quantity of EBV detection in the saliva of Ugandan adults with and without HIV-1 infection and use these data to develop a novel mathematical model of EBV infection in the tonsils. Eligible cohort participants were not taking antiviral medications, and those with HIV-1 infection had a CD4 count >200 cells/mm3. Over a 4-week period, participants provided daily oral swabs that we analysed for the presence and quantity of EBV. Compared with HIV-1 uninfected participants, HIV-1 coinfected participants had an increased risk of EBV detection in their saliva (IRR = 1.27, 95% CI = 1.10-1.47) and higher viral loads in positive samples. We used these data to develop a stochastic, mechanistic mathematical model that describes the dynamics of EBV, infected cells, and immune response within the tonsillar epithelium to analyse potential factors that may cause EBV infection to be more severe in HIV-1 coinfected participants. The model, fit using Approximate Bayesian Computation, showed high fidelity to daily oral shedding data and matched key summary statistics. When evaluating how model parameters differed among participants with and without HIV-1 coinfection, results suggest HIV-1 coinfected individuals have higher rates of B cell reactivation, which can seed new infection in the tonsils and lower rates of an EBV-specific immune response. Subsequently, both these traits may explain higher and more frequent EBV detection in the saliva of HIV-1 coinfected individuals.

The investigation of bacterial adhesion of palatine tonsils epithelial cells in patient with infectious mononucleosis

Aim. To evaluate the features of pharynx tonsils mucous membrane colonization by pathogenic and opportunistic microorganisms by using the pharynx palatine tonsils epithelium electron microscopic examination of the patients with infectious mononucleosis and acute streptococcal tonsillitis. Materials and methods. Two patients – patient P., 12 years old with a confirmed diagnosis of infectious mononucleosis and patient A., 8 years old with confirmed acute streptococcal tonsillitis. The patients were taken a bacteriological examination of the mucus and epithelium scraping from the surface of the pharyngeal tonsils. Tissue samples were examined in the electron microscopy laboratory of the Lviv National University. Results and discussion. 36 tonsils epithelial tissue micro preparations of patient A. and 41 micro preparations of patient P. were studied. Streptococcus pyogenes, Str. pneumoniae, Str. viridans, Сandida albicans, as well as non-pathogenic bacteria: Diphtheroides sp., Neisseria sp., Corynebacterium spp. were identified as result of the patient P. bacteriological examination of mucus from the surface of the pharyngeal tonsils. Staph. aureus, Str. viridans, Str. pneumoniae were identified during a bacteriological examination of patient A. Eosinophils with a two-segmented nucleus, specific granularity, phagocytosed spherical bacteria in the cytoplasm were detected during the histological examination of the materials taken from the surface of the patient’s tonsils with acute tonsillitis. Research showed that bacteria were accumulated not only in the structure of extracellular detritus. Numerous bacteria accumulations were also found in the cytoplasm of the epithelial cells in the patient with infectious mononucleosis. The cell's shape looked like a bunch of grapes. Conclusions. The electron microscopic examination showed differences in the coccal flora localization: the extracellular localization of bacteria in the patient with acute bacterial tonsillitis and intraepithelial presence of the bacteria in the patient with tonsillitis during infectious mononucleosis were found.

Viruses and oral diseases in HIV-infected individuals on long-term antiretroviral therapy: What are the risks and what are the mechanisms?

As a result of the extension of life span produced by increasing access to combined antiretroviral therapy, people living with HIV/AIDS (PLWH) face new challenges from comorbidities. Although advances in medical care for HIV infection have dramatically reduced opportunistic infections and AIDS-defining cancers, some non-AIDS-defining cancers (NADC) and specific oral diseases such as periodontitis and salivary gland disease are now more prevalent. Cancer prevention is, therefore, a priority issue in care of PLWH, stressing both restoration of immune function and reduction of non-HIV cancer risk factors (tobacco in all its forms; areca nut; heavy alcohol consumption; diets lacking antioxidant vitamins and minerals; and oncogenic virus infections) through specific interventions, especially tobacco and areca nut cessation and alcohol moderation. Detection of oral high-risk human papillomaviruses (HR-HPV) and the universal preventive HPV vaccination among PLWH should be promoted to reduce the malignancy burden, along with routine oral examinations which remain the cheapest, most reliable, most reproducible, and non-invasive tool to identify suspicious lesions. Also, considerations of oral inflammation and periodontal health are important to replication and gene expression of viruses in the mouth. Considering that a key risk factor for this scenario is the presence of oncogenic virus infection such as several members of the human herpesvirus and human papillomavirus families, here we analyze the variables involved in the seeming increase in comorbidities in PLWH.

Cancer Risk Studies and Priority Areas for Cancer Risk Appraisal in Uganda

Background

Research into aetiologies and prevention of the commonest cancers and implementation of primary and secondary prevention can reduce cancer risk and improve quality of life. Moreover, monitoring the prevalence of cancer risk factors in a specific population helps guide cancer prevention and early detection efforts and national cancer control programming.

Objective

This article aims to provide the scope and findings of cancer risk studies conducted in Uganda to guide researchers, health-care professionals, and policymakers.

Methods

Between November 2019 to January 2020, we searched peer-reviewed published articles in Pubmed, EMBASE and Cochrane Library (Cochrane central register of controlled trials-CENTRAL). We followed the recommendation of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses - the PRISMA. The primary focus was to identify cancer risk and prevention studies conducted in Uganda and published in peer-reviewed journals from January 2000 and January 2020. We used key Boolean search terms with their associated database strings.

Results

We identified 416 articles, screened 269 non-duplicate articles and obtained 77 full-text articles for review. Out of the 77 studies, we identified one (1%) randomized trial, two (2.5%) retrospective cohort studies and 14 (18%) case-control studies, 46 (60%) cross-sectional studies, five (6.4%) ecological studies, three panel studies (4%) and six (8%) qualitative studies. Cervical cancer was the most studied type of cancer in Uganda (23.4%, n = 18 studies), followed by lymphomas - both Hodgkin and Non-Hodgkin sub-types (20.7%), n = 16 studies) and breast cancer (15.6%, n = 12 studies). In lymphoma studies, Burkitt lymphoma was the most studied type of lymphoma (76%, n = 13 studies). The studies concentrated on specific cancer risk awareness, risk perceptions, attitudes, uptake of screening, uptake of human papillomavirus vaccination, the prevalence of some of the known cancer risk factors and obstacles to accessing screening services.

Conclusion

The unmet need for comprehensive cancer risk and prevention studies is enormous in Uganda. Future studies need to comprehensively investigate the known and putative cancer risk factors and prioritize the application of the higher-hierarchy evidence-generating epidemiological studies to guide planning of the national cancer control program.

Children infected by human herpesvirus 6B with febrile seizures are more likely to develop febrile status epilepticus: A case-control study in a referral hospital in Zambia

BACKGROUND

Human herpesvirus 6B (HHV-6B) is the causative agent of Roseola infantum, and has also been suggested to play a role in the pathogenesis of febrile seizures in young children, a percentage of whom go on to develop febrile status epilepticus (FSE), but the existing data is conflicting and inconclusive. HHV-6A is a distinct species, rarely detected in most parts of the world, but prior studies suggest a higher prevalence in febrile African children. We describe a case-control study comparing the frequency of HHV-6A and/or HHV-6B infections in children with febrile seizures (including FSE) and a control group of febrile children without seizures.

METHODS

We recruited children aged 6 to 60 months admitted with a febrile illness with (cases) or without (controls) seizures presenting within 48 hours of commencement of fever. Three milliliters of whole blood was centrifuged and plasma stored at -80°C for pooled screening for HHV-6B and HHV-6A by Taqman real-time polymerase chain reaction.

RESULTS

102 cases and 95 controls were recruited. The prevalence of HHV-6B DNA detection did not differ significantly between cases (5.8% (6/102)) and controls (10.5% (10/95)) but HHV-6B infection was associated with FSE (OR, 15; 95% CI, [1.99-120]; P= 0.009). HHV-6A was not detected.

CONCLUSION

Prevalence of HHV-6B was similar among cases and controls. Within the FS group, HHV-6B infection was associated with FSE, suggesting HHV-6B infections could play a role in the pathogenesis of FSE.

Frequency of EBV LMP-1 Promoter and Coding Variations in Burkitt Lymphoma Samples in Africa and South America and Peripheral Blood in Uganda

Epstein-Barr virus (EBV) is linked to several cancers, including endemic Burkitt lymphoma (eBL), but causal variants are unknown. We recently reported novel sequence variants in the LMP-1 gene and promoter in EBV genomes sequenced from 13 of 14 BL biopsies. Alignments of the novel sequence variants for 114 published EBV genomes, including 27 from BL cases, revealed four LMP-1 variant patterns, designated A to D. Pattern A variant was found in 48% of BL EBV genomes. Here, we used PCR-Sanger sequencing to evaluate 50 additional BL biopsies from Ghana, Brazil, and Argentina, and peripheral blood samples from 113 eBL cases and 115 controls in Uganda. Pattern A was found in 60.9% of 64 BL biopsies evaluated. Compared to PCR-negative subjects in Uganda, detection of Pattern A in peripheral blood was associated with eBL case status (odds ratio [OR] 31.7, 95% confidence interval: 6.8⁻149), controlling for relevant confounders. Variant Pattern A and Pattern D were associated with eBL case status, but with lower ORs (9.7 and 13.6, respectively). Our results support the hypothesis that EBV LMP-1 Pattern A may be associated with eBL, but it is not the sole associated variant. Further research is needed to replicate and elucidate our findings.

Oral shedding of human herpesviruses in patients undergoing radiotherapy/chemotherapy for head and neck squamous cell carcinoma is not affected by xerostomia

Background: Xerostomia is a very relevant and frequent complication of radiotherapy, causing the irradiated oral mucosa to be affected by bacterial, fungal and viral infections.

Objective: The objective of this study was to evaluate a possible relationship between oral shedding of human herpesviruses and xerostomia in patients with squamous cell carcinoma of head and neck submitted to radio/chemotherapy.

Methods: In this study, oral rinse samples were collected weekly from 20 patients during radiotherapy. The samples were submitted to PCR and enzymatic digestion for detection of human herpesviruses. Xerostomia was evaluated according to the Seminars in Radiation Oncology criteria.

Results: There was a higher frequency of grade 1 xerostomia (51.4%), observed first in the 1st week of radiotherapy. In the 4th week of radiotherapy, all patients presented some degree of xerostomia. Analysis of herpesviruses showed oral shedding of EBV, HHV-6 and HHV-7 in all weeks. Considering all the periods, the highest frequency was in patients with EBV excretion (55.0%), which was significantly higher than that of other viruses.

Conclusion: We observed that oral shedding of herpesviruses was not affected by xerostomia as there was a progression in their excretion, even with the evolution of xerostomia. This suggested that there is a local replication in the oral cavity that is not completely dependent of salivary excretion.

The Potential Harm of Cytomegalovirus Infection in Immunocompetent Critically Ill Children

Cytomegalovirus (CMV) is a ubiquitous infection that causes disease in congenitally infected children and immunocompromised patients. Although nearly all CMV infections remain latent and asymptomatic in immunologically normal individuals, numerous studies have found that systemic viral reactivation is common in immunocompetent critically ill adults, as measured by detection of CMV in the blood (viremia). Furthermore, CMV viremia is strongly correlated with adverse outcomes in the adult intensive care unit (ICU), including prolonged stay, duration of mechanical ventilation, and death. Increasing evidence, including from a randomized clinical trial of antiviral treatment, suggests that these effects of CMV may be causal. Therefore, interventions targeting CMV might improve outcomes in adult ICU patients. CMV may have an even greater impact on critically ill children, particularly in low and middle income countries (LMIC), where CMV is regularly acquired in early childhood, and where inpatient morbidity and mortality are inordinately high. However, to date, there are few data regarding the clinical relevance of CMV infection or viremia in immunocompetent critically ill children. We propose that CMV infection should be studied as a potential modifiable cause of disease in critically ill children, and that these studies be conducted in LMIC. Below, we briefly review the role of CMV in immunologically normal critically ill adults and children, outline age-dependent differences in CMV infection that may influence ICU outcomes, and describe an agenda for future research.