Diagnosis of COVID-19 in symptomatic patients: An updated review.

A group of pneumonia patients was detected in Hubei Province, in China in December 2019. The etiology of the disease was unknown. Later, the researchers diagnosed the novel Coronavirus as the causal agent of this respiratory disease. On February 12th 2020, the World Health Organization (WHO) officially named this disease Coronavirus disease 2019 (COVID-19). Consequently, the disease spread globally and became a pandemic. As there is no specific treatment for the symptomatic patients and several vaccines are approved by WHO, the efficacy and effectiveness of these vaccines are not fully understood yet and the availability of these vaccines are very limited. In addition, new variants and mutants of SARS-CoV-2 are thought to be able to evade the immune system of the host. So, diagnosis and isolation of infected individuals is advised. Currently, real-time reverse transcription-polymerase chain reaction (RT-PCR) is considered the gold standard method to detect novel Coronavirus, however, there are few limitations associated with RT-PCR such as false-negative results. This demanded another diagnostic tool to detect and isolate COVID-19 early and accurately. Chest computed tomography (CT) became another option to diagnose COVID-19 patients accurately (about 98% sensitivity). However, it did not apply to the asymptomatic carriers and sometimes the results were misinterpreted as from other groups of Coronavirus infection. The combination of RT-PCR and chest CT might be the best option in detecting novel Coronavirus infection early and accurately thereby allowing adaptation of measures for the prevention and control of the COVID-19.

En diciembre de 2019 se detectó un grupo de pacientes con neumonía en la provincia de Hubei, China, desconociéndose la etiología de la enfermedad. Posteriormente, los investigadores señalaron al nuevo coronavirus como agente causal de esta enfermedad respiratoria. El 12 de febrero de 2020, la Organización Mundial de la Salud (OMS) la designó oficialmente como enfermedad por coronavirus de 2019 (COVID-19). A continuación, dicha enfermedad se propagó a nivel global, y se convirtió en una pandemia. No existe tratamiento específico para los pacientes sintomáticos, y la OMS ha aprobado diversas vacunas. Sin embargo, la eficacia y la efectividad de las mismas no se comprende plenamente aún, siendo muy limitada su disponibilidad. Además, se piensa que las diferentes variantes y mutaciones del SARS-CoV-2 son capaces de evadir el sistema inmune del huésped. Por tanto, se recomienda el diagnóstico y aislamiento de las personas infectadas. Actualmente se considera la reacción en cadena de la polimerasa con transcriptasa inversa (RT-PCR) a tiempo real el método de referencia para detectar el nuevo coronavirus. Sin embargo, existen algunas limitaciones asociadas a RT-PCR tales como los resultados falso-negativos. En consecuencia, ello ha demandado otra herramienta diagnóstica para detectar y aislar la COVID-19 de manera temprana y precisa. La tomografía computarizada (TC) de tórax se ha convertido en otra opción para diagnosticar de manera precisa a los pacientes con COVID-19 (cerca del 98% de sensibilidad). Sin embargo no se aplica a los portadores asintomáticos, y a veces se han malinterpretado los resultados como en el caso de otros grupos de infección por coronavirus. La combinación de RT-PCR y TC de tórax podría ser la mejor opción para detectar la nueva infección por coronavirus de manera temprana y precisa, permitiendo, por tanto, la adaptación de las medidas para la prevención y el control de la COVID-19.

Alpaca semen quality in relation to different diets.

The aim of the present study was to evaluate the biochemical composition of seminal plasma, along with semen quality, of alpacas maintained on different diets (hay; hay+pasture grazing; pasture grazing+sheep concentrate; pasture grazing+horse concentrate; Periods 1-4, respectively). Alpacas (n=5) were fed the four different diets for a period of 6 weeks each. During the period of feeding of each diet, semen was collected using an artificial vagina to determine its volume, viscosity, sperm concentration and sperm motility. Moreover, testicular volume and body condition score were evaluated. Seminal plasma was analysed biochemically to measure total protein, triglyceride, cholesterol, γ-glutamyl transferase, alanine aminotransferase (ALT) and alkaline phosphatase levels. Protein profiles were investigated using one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. There was high variability in semen parameters between different males maintained on the same diet. Semen volume increased significantly (P<0.05) when alpacas were fed diets containing commercial sheep and horse concentrates. In contrast, sperm concentration and motility decreased significantly (P<0.05) from Period 1 to Period 4. Dietary changes had no effect on viscosity. Significant reductions were seen in triglyceride and cholesterol content, as well as γ-glutamyl transferase, ALT and alkaline phosphatase concentrations, from Period 1 to Period 4. Regardless of experimental period, a wide variation was seen in seminal plasma enzyme concentrations between alpacas, whereas diet had no effect on glucose and total protein concentrations in the seminal plasma. Eight protein bands, with molecular weights ranging from 200 to 14kDa, were considered in electrophoresis gel after image analysis. Proteins fractions of the 14-kDa (total protein express in mddL(-1) with a molecular weight of 14-kDa, TP8) and 21-kDa (total protein express in mddL(-1) with a molecular weight of 21-kDa, TP7) bands were not present in all samples of alpaca seminal plasma. There were no significant changes in the concentration of any protein fractions during the four periods. Moreover, the protein fraction of the 60-kDa (total protein express in mddL(-1) with a molecular weight of 60-kDa, TP3) band was the most prevalent in all periods. These results demonstrate that there are marked changes in semen quality, as well as some parameters related to the composition of alpaca seminal plasma, that are dependent on diet, which may indicate the need for specific diet formulation to improve reproductive performance. We hypothesise that, in alpacas, the mechanisms underlying the changes in some reproductive traits in response to feeding regimens could be related to changes in the endocrine-gonadal system.

Testicular cytology of alpaca: comparison between impressed and smeared slides.

Testicular fine needle aspiration (TFNA) has proven to be a simple and minimally invasive procedure, which allows assessments of cytological parameters of seminiferous epithelium/tubules more accurately in a short time. Though this technique does not cause negative effects on sperm quality or any damage to testicular tissue, its use is very limited in male animal infertility diagnostics. Report on the use of this technique in South American Camelids (SAC) is very limited. Therefore, the aim of this study was to evaluate the efficacy of TFNA for identification of different testicular cells and cell indices, and their correlation with that of impression cytology. A total of 98 slides were prepared from testes of six adult alpaca males, collected immediately after slaughter. Aspiration samples were performed by inserting a fine butterfly needle (21 G) connected to a 50 ml syringe into a testicle and multiple plane aspirations were carried out to obtain the materials destined to the smear. Three different imprints on slides were taken from each testicle. All slides were air-dried, stained with modified May--Grünwald--Giemsa (MGG) stain and then examined under light microscope with 1000× magnifications. Spermatogenic cells such as, spermatogonia (Sg), primary spermatocytes, secondary spermatocytes, early spermatids (ab), late spermatids (cd) and spermatozoa, and Sertoli cells were counted. The spermatozoa percentage was expressed as spermatic index (SI) and the number of Sertoli cells, counted apart, was expressed as sertoli cell index (SEI). There was not any significant difference between the spermatogenic cell parameters obtained from the two types of slides, but SEI were significantly different in two types of smears. The results of the study provide support for the use of TFNA as a useful minimally invasive modality to identify different spermatogenetic cell classes in alpaca. Moreover, the possibility to standardize this method might provide a greater impulse to the clinical diagnostics of SAC male infertility.