Browsing by Autor "Natalia Zubieta DeUrioste"

Now showing 1 - 3 of 3

COVID-19 Mortality Is Attenuated at High Tropical and Subtropical Altitude: An Observational Study of a Database Covering Five Latin American Countries
(European Society of Medicine, 2023) Natalia Zubieta DeUrioste; Christian Reyes; Lida Sanchez; Nestor Subieta; Alfredo Merino‐Luna; Iván Solarte; Raffo Escalante-Kanashiro; José Suazo; E Poma; R.D. Aguilar
The COVID-19 pandemic, caused by the SARS-COV-2 virus, has had devastating consequences worldwide. Remarkably, the incidence, virus transmission capacity, and severity of COVID-19 have been reported to be significantly decreased in high-altitude human populations. The clinical significance of these findings is enormous, as they suggest that permanent inhabitants of high altitudes have developed adaptive protective changes against certain pathologies. However, these observations have been overshadowed by contradictory reports on the COVID-19 mortality rate at high altitude, ascribed to low population densities. These interpretations, however, fail to consider that the environmental conditions of high-altitude regions of the temperate and tropical geographical zones are radically different from each other. Contrary to common thought, the conditions of high-altitude areas of countries within the tropical zone are so benign that they have favored the growth and development of densely populated cities. In this work, we use data from a COVID-19 database covering five Latin American countries in the tropical and subtropical geographic zone that corresponded to the period between the start of the pandemic and the end of 2020, when no vaccine was yet available. Our results reveal that residing above 1,000 m in tropical countries was a protective factor against COVID-19 mortality. Interestingly, this protective effect was independent of population size. The findings presented here, and those from other similar studies, substantiate the need for more research to reveal the secrets of the physiology of permanent high-altitude residents. In conclusion, our findings clearly demonstrate that the high-altitude environment in tropical and subtropical geographic zones significantly contributes to the decreased mortality impact of the SARS-COV-2 virus in high-altitude-exposed populations.
Decreased incidence, virus transmission capacity, and severity of COVID-19 at altitude on the American continent
(2020) Christian Arias‐Reyes; Favio Carvajal-Rodriguez; Liliana Poma-Machicao; Fernanda Aliaga-Raudan; Danuzia A. Marques; Natalia Zubieta DeUrioste; Roberto A. Accinelli; Edith M. Schneider Gasser; Gustavo Zubieta‐Calleja; Mathias Dutschmann
Abstract The coronavirus disease 2019 (COVID-19) outbreak in North, Central, and South America has become the epicenter of the current pandemic. We have suggested previously that the infection rate of this virus might be lower in people living at high altitude (over 2,500 m) compared to that in the lowlands. Based on data from official sources, we performed a new epidemiological analysis of the development of the pandemic in 23 countries on the American continent as of May 23, 2020. Our results confirm our previous finding, further showing that the incidence of COVID-19 on the American continent decreases significantly starting at 1,000 m above sea level (masl). Moreover, epidemiological modeling indicates that the virus transmission rate capacity is lower in the highlands (>1,000 masl) than in the lowlands (<1,000 masl). Finally, evaluating the differences in the recovery percentage of patients, the death-to-case ratio, and the theoretical fraction of undiagnosed cases, we found that the severity of COVID-19 is also decreased above 1,000 m. We conclude that the impact of the COVID-19 decreases significantly with altitude. Highlights There is a negative correlation between altitude and COVID-19 incidence on the American Continent starting from 1,000 m above sea level. The transmission rate of SARS-CoV-2 is lower in the highlands than in the lowlands. The severity of COVID-19 decreases significantly with increased altitude.
Why is it Not Possible to Predict, Through Tests at Sea Level, Who Will Have AMS?
(Elsevier BV, 2017) Gustavo Zubieta‐Calleja; Natalia Zubieta DeUrioste
Some people do not present AMS on several altitude exposures, however, unexplainably, they may have it occasionally. Several tests have been tried in order to determine who will have AMS, however, none to date are able to achieve with absolute certainty who will get AMS. Some tests include having subjects breathe a hypoxic mixture. Others have created exercise protocols with exposure to hypoxia and some other techniques. However, none have been successful. We have successfully diagnosed and treated patients with AMS of different intensity, over many years of work at high altitude, some having undiscovered pathologies that became evident on exposure to high altitude. For example, interauricular communications, nephropaties, leading to essential hypertension, cardiac arrhythmias, presence of a kidney stone that did not block the urine pathway completely, abnormal arteries in the kidney, secuelae of pulmonary disease with localized fibrosis, relative anemia due to poor bone marrow response, falciform anemia, and many others. However, those that apparently have no evident disease can present severe cases of dehydration, particularly while doing exercise at high altitude. This of course, can be quite debilitating and if pushed beyond rationale can lead to severe complications. Performing a very precise diagnosis is difficult and there is still much to study in order to understand hypoxia thoroughly. One of the explanations for the occasional presence of AMS could be the presence of subclinical viral infections. We live with viruses, and when the virus is not so aggressive and not present in sufficient quantities, the organism has an internal struggle that uses up the energy. If the person ascends a mountain in this condition, his reserve to face hypoxic stress is limited and hence may complications appear. Likewise, if the person prior to the ascent had an different type of food, with unusual spices, or with unusual bacteria, then there is an inflammation of the bowels and the endothelial cells of the gastrointestinal tract particularly at the colon level, that may not be able to absorb water as efficiently as under normal circumstances. This could lead to a more severe case of dehydration and hence AMS. There are probably many other factors which include stress from other psychological difficulties, or even exposure to toxics that are inhaled and produce inflammation in the respiratory tract. Furthermore, those training at high altitude can overdo the exercise efforts, with great willpower, leading to very increased pulmonary artery pressure and hence a dilated right heart. This overcharged effort of the muscle cells in the right heart can give rise to inflammation and microlesions that render the heart mildly insufficient in its capacity for pumping blood. On going higher in a sports competition, the optimal heart function is diminished and hence AMS can appear. This is due to the fact that the Adaptation to High Altitude Formula has not been respected in relation to time, where an adequate and timely increase of red blood cells is essential thereby generating subacute high altitude heart disease.