Zika virus (ZIKV) is an emerging mosquito-transmitted flavivirus that now causes epidemics affecting millions of people on multiple continents. The virus has received global attention because of some of its unusual epidemiological and clinical features, including persistent infection in the male reproductive tract and sexual transmission, an ability to cross the placenta during pregnancy and infect the developing fetus to cause congenital malformations, and its association with Guillain-Barre syndrome in adults. This past year has witnessed an intensive effort by the global scientific community to understand the biology of ZIKV and to develop pathogenesis models for the rapid testing of possible countermeasures. Here, we review the recent advances in and utility and limitations of newly developed mouse and nonhuman primate models of ZIKV infection and pathogenesis.

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Animal Models of Zika Virus Infection, Pathogenesis, and Immunity

Arboviruses such as Chikungunya (CHIKV), Dengue (DENV), and Zika virus (ZIKV) have emerged as a significant public health concern in Mexico. The existing literature lacks evidence regarding the dispersion of arboviruses, thereby limiting public health policy's ability to integrate the diagnosis, management, and prevention. This study seeks to reveal the clinical symptoms of CHIK, DENV, and ZIKV by age group, region, sex, and time across Mexico. The confirmed cases of CHIKV, DENV, and ZIKV were compiled from January 2012 to March 2020. Demographic characteristics analyzed significant clinical symptoms of confirmed cases. Multinomial logistic regression was used to assess the association between clinical symptoms and geographical regions. Females and individuals aged 15 and older had higher rates of reported significant symptoms across all three arboviruses. DENV showed a temporal variation of symptoms by regions 3 and 5, whereas ZIKV presented temporal variables in regions 2 and 4. This study revealed unique and overlapping symptoms between CHIKV, DENV, and ZIKV. However, the differentiation of CHIKV, DENV, and ZIKV is difficult, and diagnostic facilities are not available in rural areas. There is a need for adequately trained healthcare staff alongside well-equipped lab facilities, including hematological tests and imaging facilities.

Clinical Symptoms of Arboviruses in Mexico

Summary Rocky Mountain spotted fever, a tick-borne zoonosis caused by Rickettsia rickettsii , is among the most lethal of all infectious diseases in the Americas. In Mexico, the disease was first described during the early 1940s by scientists who carefully documented specific environmental determinants responsible for devastating outbreaks in several communities in the states of Sinaloa, Sonora, Durango, and Coahuila. These investigators also described the pivotal roles of domesticated dogs and Rhipicephalus sanguineus sensu lato (brown dog ticks) as drivers of epidemic levels of Rocky Mountain spotted fever. After several decades of quiescence, the disease re-emerged in Sonora and Baja California during the early 21st century, driven by the same environmental circumstances that perpetuated outbreaks in Mexico during the 1940s. This Review explores the history of Rocky Mountain spotted fever in Mexico, current epidemiology, and the multiple clinical, economic, and social challenges that must be considered in the control and prevention of this life-threatening illness.

Rocky Mountain spotted fever in Mexico: past, present, and future

The Zika virus disease (ZVD) has had a huge impact on public health in Colombia for the numbers of people affected and the presentation of Guillain-Barre syndrome (GBS) and microcephaly cases associated to ZVD. A retrospective descriptive study was carried out, we analyze the epidemiological situation of ZVD and its association with microcephaly and GBS during a 21-month period, from October 2015 to June 2017. The variables studied were: (i) ZVD cases, (ii) ZVD cases in pregnant women, (iii) laboratory-confirmed ZVD in pregnant women, (iv) ZVD cases associated with microcephaly, (v) laboratory-confirmed ZVD associated with microcephaly, and (vi) ZVD associated to GBS cases. Average number of cases, attack rates (AR) and proportions were also calculated. The studied variables were plotted by epidemiological weeks and months. The distribution of ZVD cases in Colombia was mapped across the time using Kernel density estimator and QGIS software; we adopted Kernel Ridge Regression (KRR) and the Gaussian Kernel to estimate the number of Guillain Barre cases given the number of ZVD cases. One hundred eight thousand eighty-seven ZVD cases had been reported in Colombia, including 19,963 (18.5%) in pregnant women, 710 (0.66%) associated with microcephaly (AR, 4.87 cases per 10,000 live births) and 453 (0.42%) ZVD associated to GBS cases (AR, 41.9 GBS cases per 10,000 ZVD cases). It appears the cases of GBS increased in parallel with the cases of ZVD, cases of microcephaly appeared 5 months after recognition of the outbreak. The kernel density map shows that throughout the study period, the states most affected by the Zika outbreak in Colombia were mainly San Andres and Providencia islands, Casanare, Norte de Santander, Arauca and Huila. The KRR shows that there is no proportional relationship between the number of GBS and ZVD cases. During the cross validation, the RMSE achieved for the second order polynomial kernel, the linear kernel, the sigmoid kernel, and the Gaussian kernel are 9.15, 9.2, 10.7, and 7.2 respectively. This study updates the epidemiological analysis of the ZVD situation in Colombia describes the geographical distribution of ZVD and shows the functional relationship between ZVD cases and GBS.

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Zika virus disease, microcephaly and Guillain-Barré syndrome in Colombia: epidemiological situation during 21 months of the Zika virus outbreak, 2015–2017

Zika virus (ZIKV) emerged in Latin America and the Caribbean (LAC) region in 2013, with serious implications for population health in the region. In 2016, the World Health Organization declared the ZIKV outbreak a Public Health Emergency of International Concern following a cluster of associated neurological disorders and neonatal malformations. In 2017, Zika cases declined, but future incidence in LAC remains uncertain due to gaps in our understanding, considerable variation in surveillance and the lack of a comprehensive collation of data from affected countries. Our analysis combines information on confirmed and suspected Zika cases across LAC countries and a spatio-temporal dynamic transmission model for ZIKV infection to determine key transmission parameters and projected incidence in 90 major cities within 35 countries. Seasonality was determined by spatio-temporal estimates of Aedes aegypti vectorial capacity. We used country and state-level data from 2015 to mid-2017 to infer key model parameters, country-specific disease reporting rates, and the 2018 projected incidence. A 10-fold cross-validation approach was used to validate parameter estimates to out-of-sample epidemic trajectories. There was limited transmission in 2015, but in 2016 and 2017 there was sufficient opportunity for wide-spread ZIKV transmission in most cities, resulting in the depletion of susceptible individuals. We predict that the highest number of cases in 2018 would present within some Brazilian States (Sao Paulo and Rio de Janeiro), Colombia and French Guiana, but the estimated number of cases were no more than a few hundred. Model estimates of the timing of the peak in incidence were correlated (p < 0.05) with the reported peak in incidence. The reporting rate varied across countries, with lower reporting rates for those with only confirmed cases compared to those who reported both confirmed and suspected cases. The findings suggest that the ZIKV epidemic is by and large over within LAC, with incidence projected to be low in most cities in 2018. Local low levels of transmission are probable, but the estimated rate of infection suggests that most cities have a population with high levels of herd immunity.

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Projecting the end of the Zika virus epidemic in Latin America: a modelling analysis

Introduction Since 2014, autochthonous circulation of Zika virus (ZIKV) in the Americas was detected (Easter Island, Chile). In May 2015, Brazil confirmed autochthonous --transmission and in October of that year Colombia reported their first cases. Now more than 52 countries have reported cases, including Mexico. To deal with this contingency in Mexico, several surveillance systems, in addition to systems for vector-borne diseases were strengthened with the participation of all health institutions. Also, the Ministry of Health defined an Action Plan against ZIKV for the whole country. Methods We analyzed 93 autochthonous cases of ZIKV disease identified by Epidemiological Surveillance System for Zika Virus in Mexico. All autochthonous cases confirmed by laboratory since November 25, 2015 to February 19, 2016 were included. A description of clinical and epidemiological characteristics of 93 cases of ZIKV disease are presenting and, we describe the Action Plan against this public health emergency. Results The distribution of cases by sex was 61 men and 32 women; mean age was 35 years old (S.D. 15, range 6-90). The main clinical features in the 93 cases were fever (96.6%), rash (93.3%), non-purulent conjunctivitis (88.8%), headache (85.4%), and myalgia (84.3%). No deaths were reported. Conclusion The ZIKV epidemic poses new challenges to public health systems. The information provided for basic, clinical, and epidemiological research, in addition to the data derived from epidemiological surveillance is essential. However, there are still many unanswered questions regarding mechanisms of transmission, complications, and impact of this virus.

Clinical and Epidemiological Characterization of Laboratory-Confirmed Autochthonous Cases of Zika Virus Disease in Mexico.

Objective Since the 2009 influenza pandemic, Latin American (LA) countries have strengthened their influenza surveillance systems. We analyzed influenza genetic sequence data from the 2017 through 2018 Southern Hemisphere (SH) influenza season from selected LA countries, to map the availability of influenza genetic sequence data from, and to describe, the 2017 through 2018 SH influenza seasons in LA. Methods We analyzed influenza A/H1pdm09, A/H3, B/Victoria and B/Yamagata hemagglutinin sequences from clinical samples from 12 National Influenza Centers (NICs) in ten countries (Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Mexico, Paraguay, Peru and Uruguay) with a collection date from epidemiologic week (EW) 18, 2017 through EW 43, 2018. These sequences were generated by the NIC or the WHO Collaborating Center (CC) at the U.S Centers for Disease Control and Prevention, uploaded to the Global Initiative on Sharing All Influenza Data (GISAID) platform, and used for phylogenetic reconstruction. Findings Influenza hemagglutinin sequences from the participating countries (A/H1pdm09 n = 326, A/H3 n = 636, B n = 433) were highly concordant with the genetic groups of the influenza vaccine-recommended viruses for influenza A/H1pdm09 and influenza B. For influenza A/H3, the concordance was variable. Conclusions Considering the constant evolution of influenza viruses, high-quality surveillance data—specifically genetic sequence data, are important to allow public health decision makers to make informed decisions about prevention and control strategies, such as influenza vaccine composition. Countries that conduct influenza genetic sequencing for surveillance in LA should continue to work with the WHO CCs to produce high-quality genetic sequence data and upload those sequences to open-access databases.

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Genetic evolution of influenza viruses among selected countries in Latin America, 2017-2018.

Background: During Epidemiological Week 36 of 2013, the Mexican Epidemiological Surveillance System (SINAVE) identified two probable cases of cholera in Mexico City.
Methods: Both samples were processed by DNA sequencing and biochemical analyses at the Institute of Epidemiological Diagnosis and Reference "Dr. Manuel Martinez Baez" (InDRE) and compared with the circulating strain of the Caribbean.
Results: V. cholerae serogroup O1, serotype Ogawa, biotype El Tor, toxigenic, was confirmed positive, then a detailed study from September 2nd, 2013 to August 27th, 2014 was carried out where a total of 201 laboratoryconfirmed cases of V. cholerae O1 toxigenic were reported in in seven states of Mexico; 50.7% were men. The average of the number of evacuations was 8 (range 0 to 48). The mean duration of diarrhoea was 2 days. The age range of the cases was from 3 months to 88 years. The 53.2% were identified without dehydration data, 21.9% with mild, 19.9% with moderate and 5.0% with severe dehydration; 65.0% received outpatient care, 24% hospitalization, and 11% in Observation or Emergency.
Conclusion: The timely detection of cases plays an important role in promotion, detection and control actions. The notification of probable cases in less than 24 h sharing the information obtained in the National Public Health Laboratory Network (RNLSP) evidenced an immediate response; triggering actions for the intentional search of cases, epidemiological surveillance, health promotion and prevention and control of diseases for adequate control of an epidemic.

https://www.longdom.org/open-access/clinical-and-epidemiological-characterization-of-cholera-mexico20132014-2329-8731-1000175.pdf

José Alberto Díaz Quiñonez

Papers

Clinical and Epidemiological Characterization of Laboratory-Confirmed Autochthonous Cases of Zika Virus Disease in Mexico.

Genetic evolution of influenza viruses among selected countries in Latin America, 2017-2018.

Clinical and Epidemiological Characterization of Cholera, Mexico 2013-2014