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Introduction: Herpes zoster (HZ; i.e., shingles) is caused by the reactivation of varicella zoster virus leading to a painful dermatomal rash. An increasing trend in cases of HZ is evident worldwide; however, there is a lack of comprehensive reviews for Southeast Asian countries. Methods: We performed a systematic literature review of articles published until May 2022 that reported HZ epidemiology, clinical management, and health economic data in six Southeast Asian countries: Indonesia, Malaysia, the Philippines, Singapore, Thailand, and Vietnam. Literature searches were conducted in Medline, Scopus, Embase, and gray literature. Articles written in English or local languages were considered for inclusion. Results: In total, 72 publications were included in the study; 22 were case studies and over 60% originated in Singapore and Thailand. Only two studies (data from Thailand) reported incidence of HZ. The proportion of patients reported with HZ was 0.68–0.7% among dermatology clinics, 0.14% at one emergency department (5.3% of dermatology cases) in Singapore, and 3% of admissions at another hospital in Singapore. Pain was the most common symptom associated with HZ, reported in 74.21–100% of patients. HZ complications were reported in 10.2–21.2% of patients, and the proportions with postherpetic neuralgia and HZ ophthalmicus were 6.3–50% and 4.98–28.57%, respectively. Additionally, there is a lack of comprehensive, up-to-date HZ economic data, with only six studies identified for the Philippines, Singapore, and Thailand. Conclusions: Overall, there are limited data reporting incidence and prevalence of HZ in Southeast Asia at a national level. High rates of complications, symptoms, and abundance of case reports suggest substantial healthcare resource utilization for patients with HZ and highlight the need for further research in Southeast Asia assessing the societal impact. [ABSTRACT FROM AUTHOR]

Background: Varicella zoster virus (VZV) is one of the eight known human herpesviruses. Initial VZV infection results in chickenpox, while viral reactivation following a period of latency manifests as shingles. Separate vaccines exist to protect against both initial infection and subsequent reactivation. Controversy regarding chickenpox vaccination is contentious with most countries not including the vaccine in their childhood immunization schedule due to the hypothesized negative impact on immune-boosting, where VZV reactivation is suppressed through exogenous boosting of VZV antibodies from exposure to natural chickenpox infections.Methods: Population-level chickenpox and shingles notifications from Thailand, a country that does not vaccinate against either disease, were previously fitted with mathematical models to estimate rates of VZV transmission and reactivation. Here, multiple chickenpox and shingles vaccination scenarios were simulated and compared to a model lacking any vaccination to analyze the long-term impacts of VZV vaccination.Results: As expected, simulations suggested that an introduction of the chickenpox vaccine, at any coverage level, would reduce chickenpox incidence. However, chickenpox vaccine coverage levels above 35% would increase shingles incidence under realistic estimates of shingles coverage with the current length of protective immunity from the vaccine. A trade-off between chickenpox and shingles vaccination coverage was discovered, where mid-level chickenpox coverage levels were identified as the optimal target to minimize total zoster burden. Only in scenarios where shingles vaccine provided lifelong immunity or coverage exceeded current levels could large reductions in both chickenpox and shingles be achieved.Conclusions: The complicated nature of VZV makes it impossible to select a single vaccination scenario as universal policy. Strategies focused on reducing both chickenpox and shingles incidence, but prioritizing the latter should maximize efforts towards shingles vaccination, while slowly incorporating chickenpox vaccination. Alternatively, countries may wish to minimize VZV complications of both chickenpox and shingles, which would lead to maximizing vaccine coverage levels across both diseases. Balancing the consequences of vaccination to overall health impacts, including understanding the impact of an altered mean age of infection for both chickenpox and shingles, would need to be considered prior to any vaccine introduction. [ABSTRACT FROM AUTHOR]

Purpose: To determine the prevalence of viral infections in patients with hypertensive anterior uveitis in Thailand from polymerase chain reaction (PCR) of aqueous humor.Methods: Thirty-one patients with anterior uveitis with intraocular pressure (IOP) above 25 mmHg were included for PCR analysis for cytomegalovirus (CMV), herpes simplex (HSV), varicella-zoster (VZV), rubella, chikungunya and Zika virus.Results: The prevalence of PCR-positive results was 32%, including 19% for CMV, 10% for HSV, and 3% for VZV; PCR for other tested viruses demonstrated negative results. PCR-positive patients exhibited satisfactory IOP control with antiviral and anti-glaucomatous treatment compared to PCR-negative patients, and more than half of PCR-negative patients required glaucoma surgery within 12 months (P = .01).Conclusion: PCR evidence of infection with herpes group viruses was found in one-third of patients with hypertensive anterior uveitis; CMV being the most common pathogen. The PCR-positive group generally responded well to a combination of antiviral and anti-glaucoma treatment. [ABSTRACT FROM AUTHOR]

In this paper, a mathematical model depicting the transmission dynamics of Chickenpox is developed by incorporating a new parameter denoting the rate of precautionary measures. The influence and the importance of following precautionary measures are showed by applying the real data collected at Phuket province, Thailand. The model analysis such as positivity and boundedness of the solutions are provided. The rate of precaution for the spread the of chickenpox was a factor that influenced the basic reproductive number, which was calculated using the next-generation matrix approach. The model's equilibrium points are identified, and the condition for the disease-free equilibrium's local and global asymptotic stability is established. The model also shows forward bifurcation. Numerical simulation is carried out to show the importance of considering the precautionary measures while controlling the disease spread and the influence of those introduced parameters are depicted graphically. Though our results, we concluded that the rate of precautionary measures plays an vital role at the same time it reduces the chance of getting infected by Chickenpox virus. • The Mathematical model is developed to understand the control of Chickenpox. • Diseases spread among people with and without complications were studied. • Stability of equilibrium points were examined by Routh and Castillo theorems. • While studying the influence of transmission rate, we ended up with forward bifurcation. • In our study of transmission rate, we discovered forward bifurcation. • We proved that, Multiple precautions = lower infection risk, reduced R 1. [ABSTRACT FROM AUTHOR]

The dynamics of Plasmodium vivax infection is characterized by reactivation of hypnozoites at varying time intervals. The relative contribution of new P. vivax infection and reactivation of dormant liver stage hypnozoites to initiation of blood stage infection is unclear. In this study, we investigate the contribution of new inoculations of P. vivax sporozoites to primary infection versus reactivation of hypnozoites by modeling the dynamics of P. vivax infection in Thailand in patients receiving treatment for either blood stage infection alone (chloroquine), or the blood and liver stages of infection (chloroquine + primaquine). In addition, we also analysed rates of infection in a study in Papua New Guinea (PNG) where patients were treated with either artesunate, or artesunate + primaquine. Our results show that up to 96% of the P. vivax infection is due to hypnozoite reactivation in individuals living in endemic areas in Thailand. Similar analysis revealed the around 70% of infections in the PNG cohort were due to hypnozoite reactivation. We show how the age of the cohort, primaquine drug failure, and seasonality may affect estimates of the ratio of primary P. vivax infection to hypnozoite reactivation. Modeling of P. vivax primary infection and hypnozoite reactivation provides important insights into infection dynamics, and suggests that 90–96% of blood stage infections arise from hypnozoite reactivation. Major differences in infection kinetics between Thailand and PNG suggest the likelihood of drug failure in PNG. Author Summary: Plasmodium vivax is one of two major parasite species causing human disease. This parasite can lie dormant in the liver as a hypnozoite, before later reactivating to cause blood-stage infection. Treatment to eliminate the dormant hypnozoite stage relies mostly on a single drug—primaquine. Understanding the rate of primary infection versus hypnozoite reactivation is important to understanding primaquine efficacy and drug resistance, as well as the development of new drugs targeting hypnozoites. Here we use mathematical modeling to analyse data from two clinical cohorts and show that up to 96% of infections may be caused by hypnozoite reactivation. We also use modeling to understand the impact of drug resistance, seasonal infection and subject age. [ABSTRACT FROM AUTHOR]

Purpose: To determine the infectious causes of posterior uveitis (PU) and panuveitis (panU) in Thailand. Methods: We investigated the infectious causes of uveitis involving the posterior segment of the eye by using real-time polymerase chain reaction (PCR) for cytomegalovirus (CMV), herpes simplex virus (HSV-1, HSV-2), varicella zoster virus and Toxoplasma gondii ( T. gondii) DNA in intraocular samples of 80 human immunodeficiency virus (HIV)-negative patients. Additionally, in 61 patients, we performed Goldmann-Witmer coefficient (GWC) analysis for T. gondii. Results: Twenty-four (30 %) patients with PU and/or panU had a positive PCR result. Overall, CMV was the most frequently identified organism. While CMV was the most common cause of uveitis in the patients on immunosuppressive medications for nonocular disorders, HSV was the most common cause of posterior and panuveitis in the patients not receiving such medication. In 38 PU patients, CMV was the most common detected pathogen. In 42 panU patients, CMV and HSV-2 were the most frequently identified pathogens. Out of 61 paired samples analyzed for T. gondii by GWC analysis, only 1 revealed a positive result. There was no difference in PCR results between aqueous humor and vitreous samples. Conclusions: CMV was the most frequently identified infectious organism in posterior and panuveitis of HIV-1-negative Thai patients. Aqueous humor and vitreous samples showed similar diagnostic values in PCR analysis. [ABSTRACT FROM AUTHOR]

This study aimed to measure the herpes zoster-associated burden of illness, healthcare utilization, and costs among Thai patients. This prospective cohort study of 180 patients aged ≥ 50 years and healthy, or ≥ 20 years and immunosuppressed, with zoster rash, was conducted in Bangkok and its environs, Thailand, during 2007-2008. Each patient was followed for six months for zoster-associated rash, pain, quality of life (QoL), and healthcare utilization and costs. A total of 180 subjects were enrolled in the study. Their mean ± standard deviation (SD) age was 58.9 ± 13.8 years. Of the 180 patients enrolled, 138 (76.7%), 34 (18.9%) and eight (4.4%) patients were elderly, HIV-infected, and receiving immunosuppressive agents, respectively; 35 (19.4%) had post-herpetic neuralgia (PHN), and 13 (7.2%) had zoster ophthalmicus. The severity of zoster pain was moderately highly correlated with activities of daily living (ADL), at 0.68 ≤ ρ ≤ 0.76. Most patients required only one or two outpatient visits. The mean ± SD total of direct healthcare costs was 3083.4 ± 5047.0 Thai baht or ∼ 1.1% of annual income per capita. Herpes zoster contributes a significant burden of illness to both patients and the wider community. [ABSTRACT FROM AUTHOR]