Angiotensin-converting enzyme 2 in dogs with Dirofilaria immitis.

BACKGROUND: Infection by the canine heartworm, Dirofilaria immitis, causes significant cardiopulmonary disease, with progression impacted by increasing parasite numbers and duration of infection. The renin-angiotensin-aldosterone system (RAAS) is an important mediator of cardiac and pulmonary disease. Angiotensin-converting enzyme 2 (ACE2) mitigates the maladaptive effects of angiotensin II by converting it to angiotensin (1-7). We hypothesized that circulating ACE2 activity would be altered in dogs with high heartworm infection intensities relative to dogs without heartworms. METHODS: Frozen serum samples (-80 °C) from 30 dogs euthanized at Florida shelters were analyzed for ACE2 activity using liquid chromatography-mass spectrometry/mass spectroscopy and a kinetics approach with and without an ACE2 inhibitor. A convenience sample of 15 dogs without heartworms (HW0) and 15 dogs with > 50 heartworms (HW>50) was included. Heartworm number and microfilariae presence were determined at necropsy. The effects of heartworm status, body weight, and sex on ACE2 were evaluated using regression analysis. Values of P < 0.05 were considered significant. RESULTS: All HW0 dogs were D. immitis microfilariae-negative and all HW>50 dogs were D. immitis microfilariae-positive with a median adult worm count of 74 (minimum = 63, maximum = 137). The ACE2 activity of HW>50 dogs (median = 28.2 ng/ml; minimum = 13.6, maximum = 76.2) was not different from HW0 dogs (median 31.9 ng/ml; minimum = 14.1, maximum = 139.1; P = 0.53). The ACE2 activity was higher in dogs with high body weight (median 34.2 ng/ml minimum = 14.1, maximum = 76.2) than in dogs with low weight (median 27.5 ng/ml; minimum = 16.4, maximum = 139.1; P = .044). CONCLUSIONS: Heartworm infection did not impact ACE2 activity in shelter dogs with or without heartworms, but heavier dogs had higher ACE2 activity compared to lighter dogs. Comprehensive RAAS evaluation and additional clinical information would aid in understanding how ACE2 activity relates to the entire cascade and clinical status in dogs with heartworm disease.

Guidelines on epidemics in Mexico. Historical perspective.

A perspective of epidemics and pandemics in Mexico is offered, focusing on three time periods, namely, end of the 18th century, the 20th century, and the 21st century, in order to analyze how they were approached by health and government authorities, as well as the challenges they have represented. Historical documentary sources were consulted and, in current cases, participation in them was analyzed. Epidemiological and social historical methodologies were combined. The presence of epidemics in Mexico is a constant on its evolution, which highlights the need for the epidemiological surveillance system to be updated, the importance of being prepared to face an epidemic and to develop a contingency plan.

Se ofrece una perspectiva de las epidemias y pandemias en México en tres periodos: fines del siglo XVIII y siglos XX y XXI, con el fin de analizar cómo las autoridades sanitarias y gubernamentales abordaron estos problemas, así como los desafíos que han representado. Se consultaron fuentes históricas documentales y, en los casos actuales, la participación en ellos. Se combinó metodología epidemiológica e histórica social. La presencia de las epidemias en México es una constante, lo cual evidencia la necesidad de actualizar el sistema de vigilancia epidemiológica, de estar preparados para enfrentar una epidemia y de elaborar un plan de contingencia.