Identification of early warning signals previous to the occurrence of population decline or extinction is a major challenge for the conservation of animal species. Prevalence of morphological abnormalities in a population can be one of these signals. We registered morphological abnormalities in the salamander Ambystoma ordinarium. We also evaluated the relation between habitat quality and the prevalence of abnormalities in this species. We used scores from rapid bioassessment protocols (RBPs) to assess the habitat quality of streams inhabited by A. ordinarium. A preliminary survey indicated that of 29 streams where this species has been historically registered, 13 might have few or no A. ordinarium. The association between habitat quality and the incidence of morphological abnormalities was evaluated in these 16 streams. Of 502 sampled individuals, 224 (44.62%) had at least one body abnormality. Of the 224 individuals with body abnormalities, 84 (37.5%) presented more than one abnormality. Of a total of 5,522 evaluated morphological characters, 344 (6.74%) were abnormal. Partial loss of gills and missing digits were the most frequent abnormalities. Results of a binomial logistic regression indicated that the probability of a character of an individual to be abnormal was significantly associated with habitat quality; as the levels of the quality of the habitat increased, the prevalence of morphological abnormalities decreased. These results suggest that RBPs are a quick and useful method for assessing the habitat quality of streams inhabited by A. ordinarium. Given that RBPs provide rapid and cost-effective assessments of the ecological health of aquatic ecosystems, it will be important to test if the RBPs protocols can be used to rapidly assess habitat quality for other species of stream amphibians. The negative association between habitat quality and the prevalence of morpohological abnormalities that we found indicates that habitat condition plays an important role in the high number of abnormalities registered in A. ordinarium. Therefore, our results suggest that one of the several negative effects of habitat degradation on amphibians is an increase in the frequency of morphological abnormalities with marked consequences for the survival and general fitness of aquatic amphibians.

According to the Intergovernmental Panel on Climate Change (IPCC), global temperatures have risen at an alarming pace since the early 20th century and this warming has been more pronounced since the 1970s. Temperature variations are significant because of their relation with thermal comfort and public health. In this study, we characterize the impacts of increasing maximum air temperatures in Sonora, Mexico. Heat days (HDs) and heat waves (HWs) were used as indicators to investigate historical trends in extreme heat. Furthermore, HDs were represented using a generalized linear regression model during the observed period (1966–2015) to generate future scenarios related to extreme heat and subsequently compared with six downscaled general circulation models (CNRM‐CM5, CSIRO Mk3.6.0, HadGEM2‐CC, HadGEM2‐ES, IPSL‐CM5A‐LR and IPSL‐CM5A‐MR) under low and high radiative scenarios (RCP4.5 and RCP8.5). Results of this work indicate that climate stations in Sonora have exhibited increases in the number of HDs and HWs in the historical record that can be associated to physical factors such as elevation, urban land cover and the percent of annual rainfall during the summer. Statistical and model‐based projections indicate that these trends will continue in the future up to 2060, with less moderate increases and high uncertainty noted for the difference scenarios of the downscaled models. These observed and projected trends in extreme heat are important for identifying adaptation strategies in the public and environmental health sectors in Sonora.

Human movement is a key factor in infectious diseases spread such as dengue. Here, we explore a mathematical modeling approach based on a system of ordinary differential equations to study the effect of human movement on characteristics of dengue dynamics such as the existence of endemic equilibria, and the start, duration, and amplitude of the outbreak. The model considers that every day is divided into two periods: high-activity and low-activity. Periodic human movement between patches occurs in discrete times. Based on numerical simulations, we show unexpected scenarios such as the disease extinction in regions where the local basic reproductive number is greater than 1. In the same way, we obtain scenarios where outbreaks appear despite the fact that the local basic reproductive numbers in these regions are less than 1 and the outbreak size depends on the length of high-activity and low-activity periods.

Lockdown and social distancing measures have been implemented for many countries to mitigate the impacts of the COVID-19 pandemic and prevent overwhelming of health services. However, success on this strategy depends not only on the timing of its implementation, but also on the relaxation measures adopted within each community. At the request of Sonoran Health Ministry, we developed a mathematical model to evaluate the impacts of the lockdown implemented in Hermosillo, Mexico. We compared this intervention with some hypothetical ones, varying the starting date and also the population proportion that is released, breaking the confinement. For this purpose, a Monte Carlo study was performed by considering three scenarios to define our baseline dynamics. Results showed that a hypothetical delay of two weeks, on the lockdown measures, would result in an early ACME around May 9 for hospitalization prevalence and an increase on cumulative deaths, 42 times higher by May 31, when compared to baseline. On the other hand, in respect of relaxation dynamics, the ACME levels depend on the proportion of people who gets back to daily activities or the individual behavior regarding prevention measures. It is important to stress that, according to information provided by health authorities, the ACME occurring time was closed to the one given by our model. Hence, we considered that our model resulted useful for the decision-making assessment, and that an extension of it can be used for the study of a potential second wave.

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