Photorefractive intrastromal crosslinking for correction of hyperopia: 12-month results.

PURPOSE: To evaluate the efficacy of epithelium-on photorefractive intrastromal crosslinking (PiXL), a noninvasive procedure to reduce refractive error in patients with low hyperopia. SETTING: Gemini Eye Clinic, Zlin, Czech Republic. DESIGN: Prospective single-center study. METHODS: Twenty-two low hyperopic eyes were enrolled and underwent PiXL treatment according to a standardized treatment protocol. Visual acuity, subjective distance refraction, keratometry, topography, pachymetry, subjective discomfort, and endothelial cell density (ECD) were recorded during 12-month follow-up. RESULTS: In 22 eyes, the median manifest refraction decreased significantly (P < .0001) from +0.75 diopters (D) (interquartile range [IQR], +0.63 to +1.06 D), median and IQR) diopters (D) preoperatively to +0.25 D (IQR, 0.0 to +0.50 D) at 12-month follow-up and remained stable. Seventy-seven percent of eyes achieved refraction within ± 0.50 D of emmetropia by 1 month postoperatively and was stable through 12-month follow-up. ECD was stable and did not show significant changes. There was low incidence of postoperative pain and dry eye. CONCLUSIONS: PiXL is a promising alternative to conventional laser refractive surgeries for low hyperopia. Further studies are warranted to optimize treatment parameters for a wider range of refractive errors and to evaluate the potential to improve precision.

Tick-Borne Transmission of Murine Gammaherpesvirus 68.

Herpesviruses are a large group of DNA viruses infecting mainly vertebrates. Murine gammaherpesvirus 68 (MHV68) is often used as a model in studies of the pathogenesis of clinically important human gammaherpesviruses such as Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus. This rodent virus appears to be geographically widespread; however, its natural transmission cycle is unknown. Following detection of MHV68 in field-collected ticks, including isolation of the virus from tick salivary glands and ovaries, we investigated whether MHV68 is a tick-borne virus. Uninfected Ixodes ricinus ticks were shown to acquire the virus by feeding on experimentally infected laboratory mice. The virus survived tick molting, and the molted ticks transmitted the virus to uninfected laboratory mice on which they subsequently fed. MHV68 was isolated from the tick salivary glands, consistent with transmission via tick saliva. The virus survived in ticks without loss of infectivity for at least 120 days, and subsequently was transmitted vertically from one tick generation to the next, surviving more than 500 days. Furthermore, the F1 generation (derived from F0 infected females) transmitted MHV68 to uninfected mice on which they fed, with MHV68 M3 gene transcripts detected in blood, lung, and spleen tissue of mice on which F1 nymphs and F1 adults engorged. These experimental data fulfill the transmission criteria that define an arthropod-borne virus (arbovirus), the largest biological group of viruses. Currently, African swine fever virus (ASFV) is the only DNA virus recognized as an arbovirus. Like ASFV, MHV68 showed evidence of pathogenesis in ticks. Previous studies have reported MHV68 in free-living ticks and in mammals commonly infested with I. ricinus, and neutralizing antibodies to MHV68 have been detected in large mammals (e.g., deer) including humans. Further studies are needed to determine if these reports are the result of tick-borne transmission of MHV68 in nature, and whether humans are at risk of infection.

Molecular detection of murine herpesvirus 68 in ticks feeding on free-living reptiles.

The MHV-68 (designed as Murid herpesvirus 4 (MuHV 4) strain 68) isolated from two rodents, Myodes glareolus and Apodemus flavicollis, is considered as a natural pathogen of free-living murid rodents. Recently, the detection of MHV antibodies in the blood of animals living in the same biotope as MHV-infected mice has suggested that ticks may have a role in the transmission of this pathogen. Ixodes ricinus is one the most abundant tick species in Europe known to transmit multiple pathogens causing human and animal diseases. In this study, nymphs and larvae feeding on 116 individuals of a temperate lizard species-the green lizard Lacerta viridis captured in the Slovak Karst National Park, were examined for MHV-68. The specific sequence of virion glycoprotein 150 was amplified in DNA individually isolated from I. ricinus ticks using single-copy sensitive nested polymerase chain reaction. MHV-68 was detected in ten of 649 nymphs and in five of 150 larvae, respectively. We found that 9.6% of green lizards fed at least one MHV-68-infected immature tick. Occurrence of MHV-68 within all ticks tested was 1.8%. This study is first to show that immature I. ricinus ticks feeding on free-living lizards in a Central European region could be infected with gammaherpesvirus (MHV-68), naturally infecting free-living murid rodents. Our results provide evidence supporting the hypothesis that ticks may play a mediating role in circulation of MHV-68 in nature.