Susceptibilidad de las mucosas oculares al SARS COV-2: bioseguridad sanitaria / Susceptibility of eye mucosa to SARS CoV-2: sanitary biosecurity

RESUMEN: El SARS CoV-2, agente causal de la enfermedad llamada Covid-19, infecta las mucosas digestivas y respiratorias, afectando las células epiteliales. El virus ingresa a través del receptor de membrana ACE2 provocando la disrupción de la homeostasis celular. Frecuentes reportes indican la presencia de conjuntivitis ocular en pacientes diagnosticadas con Covid-19, lo cual ha alertado a los científicos sobre el potencial foco de infección viral de las secresiones lagrimales.Los epitelios de la conjuntiva ocular sub-palpebral y corneal, se caracterizan por presentar el receptor de la enzima convertidora de angiotensina 2 (ACE2) y proteasa transmembrana asociada serina 2 (TMPRSS2), cuya interacción activa los mecanismos de liberación de citoquinas, capaces de instalar un proceso de conjuntivitis infecciosa por SARS CoV-2, pero no necesariamente hacer extensiva la infección hacia los sistemas digestivo y respiratorio.Aunque este proceso inflamatorio es más frecuente como una expresión de la infección general y más grave. Sin embargo, cualquiera sea la vía de infección o ingreso del virus SARS CoV-2 es importante considerar el riesgo de infectividad de las lágrimas y las secresiones conjuntivales en los pacientes. Este estudio pretende llamar la atención sobre las medidas de cuidados y control sanitario, incorporando mejores normas de protección personal y bioseguridad, especialmente en el áreas de oftalmología, asumiendo que la mucosa ocular puede ser una vía de entrada del virus y a la vez una fuente de contagio.También considerar la potenciación de la infección viral con las enfermedades de base asociadas, como glaucoma y diabetes.Se sugiere además incorporar estudios histológicos de la mucosa ocular para diferenciar epitelios sanos e infectados.

SUMMARY: SARS CoV-2, the causal agent of the Covid- 19 disease, infects the digestive and respiratory mucosa, affecting epithelial cells. The virus enters through the ACE2 membrane receptor causing the disruption of cell homeostasis. Frequent reports indicate the presence of ocular conjunctivitis in patients diagnosed with Covid-19, which has alerted scientists to the potential source of viral infection from lacrimal secretions. The epithelia of the sub-palpebral and corneal ocular conjunctiva are characterized by presenting the receptor for angiotensin-converting enzyme 2 (ACE2) and associated transmembrane protease serine 2 (TMPRSS2), whose interaction activates cytokine release mechanisms, with the ability to start the infectious conjunctivitis process by SARS CoV-2, but not necessarily extend the infection to the digestive and respiratory systems. Although this inflammatory process is more frequent as an expression of the general and more serious infection. However, whatever the route of infection or entry of the SARS CoV-2 virus, it is important to consider the risk of infection of tears and conjunctival secretions in patients. This study aims to draw attention to health care and control measures, incorporating better standards of personal protection and biosafety, especially in the areas of ophthalmology, assuming that the ocular mucosa can be a route of entry for the virus, and at the same time a source of contagion. A further consideration is the potential of viral infection with associated underlying diseases, such as glaucoma and diabetes. It is also suggested to incorporate histological studies of the ocular mucosa to differentiate healthy and infected epithelia.

Comparative Analysis of Polymerase Chain Reaction Assay for Herpes Simplex Virus 1 Detection in Tear

PURPOSE: To comparatively analyze the methodological efficacy of the polymerase chain reaction (PCR) assay for herpes simplex virus 1 (HSV) detection in tears. METHODS: This retrospective study reviewed the medical records of 115 patients who were clinically diagnosed with herpes keratitis, and their tear samples were collected for HSV detection. PCR positive rates were analyzed for their dependence on the PCR primers used (conventional PCR primer vs. nested PCR primer), the tear collecting method used (micropipetting vs. collection with schirmer strip), the disease manifestation and the patient's previous medication history. RESULTS: HSV DNA was detected in 23 out of 115 (20%) tear samples. The PCR positive rate in tear samples did not differ depending on the PCR primer or tear collection method used. Typical epithelial lesions showed a higher positive rate (31.4%) than atypical epithelial lesions (10.9%). The previous history of the antiviral agent seemed to affect the PCR positive rate. CONCLUSIONS: Although the PCR positive rate was not dependent on the tear collection method or primers, HSV detection in tears using PCR was shown to be a supplementary diagnostic test in typical and atypical herpes epithelitis.

Detecção do vírus herpes simples por reação em cadeia da polimerase em pacientes com ceratite herpética típica ou atípica / Molecular detection of herpes simplex virus by polymerase chain reaction in patients with typical and atypical herpetic keratitis

OBJETIVO: Avaliação dos pacientes com o quadro clínico de ceratite herpética (CH) típicas e atípicas, pela reação em cadeia da polimerase (PCR) correlacionando com o diagnóstico clínico. MÉTODOS: Foi realizada a PCR em 28 pacientes com ceratite herpética típica e atípica. RESULTADOS: A PCR foi positiva em 57,14 por cento (n=16) do total (n=28). Nos casos de CH típica a positividade foi de 60,00 por cento (n=12) em 20 casos. Para CH epitelial a positividade foi de 69,23 por cento (n=9), sendo 77,78 por cento (n=7) apenas para as lesões epiteliais dendríticas. Os casos de CH atípica apresentaram positividade de 50 por cento (n=4) em oito casos. CONCLUSÃO: Quadro clínico típico de CH teve boa correlação com o resultado positivo observado na PCR. Entretanto, metade dos pacientes com o quadro de CH atípica apresentou PCR positivo, portanto, o exame do PCR é teste importante para o auxílio e diagnóstico da CH. No caso de CH estromal, foi demonstrado que a técnica da PCR conseguiu identificar o vírus HSV.

PURPOSE: To evaluate patients with clinically typical and atypical herpetic keratitis (HK) by means of polymerase chain reaction (PCR) as compared with the clinical diagnosis. METHODS: PCR in 28 patients with clinical symptoms of typical and atypical HK was performed. RESULTS: PCR was positive in 57.14 percent (n=16) of the total cases (n=28). The test was positive in 60.0 percent (n=12) of the 20 typical HK cases. For epithelial HK, the test was positive in 69.23 percent (n=9), and 77.78 percent (n=7) only for dendritic injuries. Atypical HK presented a positive test in 50 percent (n=4) of eight cases. CONCLUSION: Clinical typical picture of HK had a good correlation with the positive result of PCR, mainly for epithelial injury of the dendritic type. However, 50 percent of the patients with atypical HK presented positive PCR. This result showed that PCR test can provide an effective HK diagnosis. In the stromal case of HK, PCR was a useful technique to identify HSV virus.