Guillain-Barré Syndrome Associated With Zika Virus Infection: A Prospective Case Series From Mexico.

Background: On May 2016, anticipating the rainy season from June to October in Mexico, we expected an increase in cases of Zika virus (ZIKV) infections. With the goal of identifying cases of GBS associated with ZIKV infection, a prospective joint study was conducted by a reference center for neurological patients and the Secretary of Health in Mexico City from July 2016 to November 2016. Methods: Serum, cerebrospinal fluid, urine, and saliva were tested by RT-PCR for ZIKV, dengue virus, and chikungunya virus in patients referred from states with reported transmissions of ZIKV infection, and with clinical symptoms of GBS according to the Brighton Collaboration criteria. Clinical, electrophysiological, and long-term disability data were collected. Results: In the year 2016 twenty-eight patients with GBS were diagnosed at our institute. In five hospitalized patients with GBS, RT-PCR was positive to ZIKV in any collected specimen. Dengue and chikungunya RT-PCR results were negative. All five patients had areflexic flaccid weakness, and cranial nerves affected in three. Electrophysiological patterns were demyelinating in two patients and axonal in three. Three patients were discharged improved in 10 days or less, and two patients required intensive care unit admission, and completely recovered during follow-up. Conclusion: Our results are similar to those reported from the state of Veracruz, Mexico, in which out of 33 samples of urine of patients with GBS two had a positive RT-PCR for ZIKV. Simultaneous processing of serum, CSF, urine, and saliva by RT-PCR may increase the success of diagnosis of GBS associated to ZIKV.

[Enfermedad de Chagas en México].

Chagas disease, which is caused by Trypanosoma cruzi, is considered to be the most serious parasitic disease in America. It is transmitted mainly by triatominae ("kissing bugs"). Mazzoti reported the first two human cases in Mexico. The form of transmission is by parasites entering the organism in feces of the insect, by blood transfusion, from mother to child, by organ transplant and laboratory accidents. In Mexico, 1.1 million people are estimated to be infected; the incidence in 2012 was 0.70 per 1,00,000 population. In 2017, the highest incidence rates were registered in Yucatán, Oaxaca and Hidalgo. The infection causes cardiomyopathies and mega-organs of the digestive tract. Diagnosis in the acute phase is by parasitological approach and, in the chronic phase, by laboratory screening studies. In Mexico's blood banks, screening for Chagas disease is mandatory; from 2007 to 2016, seroprevalence has decreased from 0.40 to 0.32 due to the improvement of donor selection processes and the ad hoc questionnaire. The targets of the parasite are neurons and smooth and myocardial muscle cells. The association of neuronal and smooth muscle destruction defines the presentation of chagas mega-syndromes. Initial manifestations of the disease can go unnoticed; 5% show apparent signs and symptoms and 30% will progress to the chronic asymptomatic phase. Currently available treatments have effect in the acute phase. For the control of Chagas disease, the Specific Action Program for the Prevention and Control of Chagas Disease (PAE Chagas 2013-2018) is available to initiate activities aimed at eliminating transfusion and congenital transmission and controlling vector transmission. The success of medical care depends on oportune detection, early etiological treatment and coverage broadening. On the other hand, monitoring and screening of pregnant women living in risk areas and blood and organ donors universal screening will enable the elimination congenital and transfusion transmission.

La enfermedad de Chagas, causada por el Trypanosoma cruzi, está considerada como la parasitosis más grave en América. Se transmite principalmente por triatominos (chinches). El doctor Mazzoti reportó los dos primeros casos humanos en México. La forma de transmisión es por la entrada al organismo de los parásitos en heces del insecto, por transfusión sanguínea, de madre a hijo, por trasplante de órganos y por accidentes de laboratorio. En México se estima que 1.1 millones de personas están infectadas; la incidencia en 2012 fue de 0.70 por 100 000 habitantes. En 2017, las mayores tasas de incidencia se registraron en Yucatán, Oaxaca e Hidalgo. La infección ocasiona miocardiopatías y megaórganos del tracto digestivo. El diagnóstico en fase aguda es por abordaje parasitológico y en fase crónica, por estudios de tamizaje por laboratorio. En los bancos de sangre de México, el estudio de la enfermedad de Chagas es de observancia obligatoria; de 2007 a 2016, la seroprevalencia ha disminuido de 0.40 a 0.32 debido a la mejora de los procesos de selección al donante y al cuestionario ad hoc. Los blancos del parásito son las células neuronales y las de los músculos liso y miocárdico. La asociación de la destrucción neuronal y del músculo liso define la presentación de los síndromes megachagásicos. Las manifestaciones iniciales de la enfermedad pueden pasar desapercibidas; 5 % de los pacientes presenta signos y síntomas aparentes y 30 % evolucionará a la fase crónica asintomática. Los tratamientos actuales tienen efecto en la fase aguda. Para el control de la enfermedad de Chagas se dispone del Programa de Acción Específico para la Vigilancia Prevención y Control de la Enfermedad de Chagas (PAE Chagas 2013-2018), encaminado a eliminar la transmisión transfusional y congénita y a controlar la transmisión vectorial. De la detección oportuna, el tratamiento etiológico temprano y la ampliación de cobertura depende el éxito de la atención médica. Por su parte, la vigilancia y tamizaje de las mujeres embarazadas que viven en zonas de riesgo y el tamizaje universal de donadores de sangre y órganos harán posible la eliminación de la transmisión connatal y transfusional.

The burden of influenza A and B in Mexico from the year 2010 to 2013: An observational, retrospective, database study, on records from the Directorate General of Epidemiology database.

Despite vaccination programs, influenza still represents a significant disease burden in Mexico. We conducted an observational, retrospective analysis to better understand the epidemiological situation of the influenza virus in Mexico. Analysis of the seasonal patterns of influenza A and B were based on the Directorate General of Epidemiology dataset of influenza-like illness(ILI), and severe acute respiratory infection(SARI) that were recorded between January 2010 and December 2013. Our objectives were 1) to describe influenza A and B activity, by age group, and subtype and, 2) to analyze the number of laboratory-confirmed cases presenting with ILI by influenza type, the regional distribution of influenza, and its clinical features. Three periods of influenza activity were captured: August 2010-January 2011, December 2011-March 2012, and October 2012-March 2013. Cases were reported throughout Mexico, with 50.3% (n = 10,320) of cases found in 18-49 year olds. Over the entire capture period, a total of 76,085 ILI/SARI episodes had swab samples analyzed for influenza, 27% were positive. During the same period, influenza A cases were higher in the 18-49 years old, and influenza B cases in both 5-17 and 18-49 age groups. Peak activity occurred in January 2012 (n = 4,159) and December 2012 (n = 348) for influenza A and B respectively. This analysis confirms that influenza is an important respiratory pathogen for children and adults in Mexico despite vaccination recommendations. School-age children and adolescents were more prone to influenza B infection; while younger adults were susceptible to both influenza A and B viruses. Over the seasons, influenza A and B co-circulated.

Detection of Zika virus in Aedes mosquitoes from Mexico.

Background: We report on the results of an entomovirological surveillance system of Aedes populations performed by the Ministry of Health of the central state of San Luis Potosí, Mexico. Methods: Indoor adult Aedes aegypti and Aedes albopictus pools collected at San Martín, Tamazunchale, Ciudad Valles, Metlapa, Ebano, Tamuin and Axtla during the dry season of 2016 were examined for the presence of dengue (DENV), chikungunya (CHIKV) and Zika (ZIKV) viruses using real-time PCR. Results: Both Ae. aegypti and Ae. albopictus were found to be infected with ZIKV in the absence of confirmed symptomatic human cases. Conclusions: The entomovirological surveillance system analysed here identified both Ae. aegypti and Ae. albopictus infected with ZIKV which triggered an immediate aggressive vector control campaign.

[Clinical and epidemiological characterization of chikungunya fever in Mexico]. / Caracterización clínica y epidemiológica de fiebre chikungunya en México.

On 6 December 2013, the Pan American Health Organization (PAHO) and the World Health Organization (WHO) reported confirmation of the first two cases of indigenous transmission of chikungunya fever (CHIK) in the Region of the Americas on the island of Sint Maarten (Netherlands Antilles). For the period 2013-2014, a total of 25 627 confirmed autochthonous cases were distributed in 43 countries, with Mexico reporting 155 cases in five states. Information on cases of CHIK in Mexico was obtained from the database of the General Directorate of Epidemiology (Ministry of Health of Mexico). The distribution of confirmed autochthonous cases of CHIK for 2015, by sex, was 64% female (5 583) and 36% male (3 085). The most frequent symptoms were fever in 98% of cases (8 564), followed by headache in 91.6% (7 941), myalgia in 89.9% (7 792), mild arthralgias in 73.5% (6 367), severe polyarthralgia in 72.6% (6 295), and exanthema in 58% (5 032). The clinical presentation of autochthonous cases of CHIK in Mexico has shown several clinical manifestations different from those seen in outbreaks in African and Asian countries and other regions in the Americas; for example, a greater percentage of cases with headache and myalgia and a smaller percentage of cases with arthralgia.

[Behavior of influenza seasons in Mexico from 2010 to 2016: Analysis and prospective]. / Comportamiento de las temporadas de influenza en México de 2010 a 2016, análisis y prospectiva.

The influenza virus spreads rapidly through recurring seasonal outbreaks during the fall and winter. Our country has the Epidemiological Surveillance System for Influenza (SISVEFLU), in operation since 2006, which has records of 558 health units of Influenza. According to the information recorded in it, we can see that the 2010-2016 influenza seasons have a biannual behavior, and that in the 2010-2011, 2012-2013, and 2014-2015 seasons, the predominant viral subtype was A (H3N2), while in the 2011-2012, 2013-2014, and 2015-2016 seasons, the predominant subtype was A (H1N1) pdm09, which was associated with an increased number of influenza cases and deaths. It is expected that the 2016-2017 season will have predominance of subtype A (H3N2) and in 2017-2018 the expected will be subtype A (H1N1) pmd09. During the 2010-2016 seasons, 53.5% of cases of influenza were women; 77% had no history of vaccination, and 36% had one or more comorbidities. As for deaths, 55% was observed in males, 85% had not been vaccinated, and 71.5% had one or more comorbidities.

Caracterización clínica y epidemiológica de fiebre chikungunya en México / Clinical and epidemiological characterization of chikungunya fever in Mexico

RESUMEN El 6 de diciembre de 2013, la Organización Panamericana de la Salud (OPS) y la Organización Mundial de la Salud (OMS) notificaron la confirmación de los dos primeros casos de transmisión autóctona en la Región de las Américas de fiebre chikungunya (CHIK) en la isla de Saint Martin (Antillas Neerlandesas). Para el período 2013-2014, el total de casos confirmados fue de 25 627 distribuidos en 43 países, donde México reportó 155 casos en cinco estados. La información de los casos de CHIK en México se obtuvo de la base de datos de la Dirección General de Epidemiología, dependiente de la Secretaría de Salud de México. La distribución por sexo de los casos autóctonos confirmados de CHIK para el año 2015 indica 64% para el sexo femenino (5 583) y 36% para el sexo masculino (3 085). Los síntomas más frecuentes fueron: fiebre en 98% de los casos (8 564), seguido por cefalea con 91,6% (7 941), mialgias en 89,9% (7 792), artralgias leves en 73,5% (6 367), poliartralgias graves en 72,6% (6 295) y exantema en 58% (5 032). La presentación clínica de los casos autóctonos de CHIK en México ha mostrado algunas características clínicas diferentes de las que se han observado en los brotes de los países africanos, asiáticos y otras regiones de América, como por ejemplo un mayor porcentaje de casos con cefalea y mialgias y un menor porcentaje de casos con artralgias.(AU)

ABSTRACT On 6 December 2013, the Pan American Health Organization (PAHO) and the World Health Organization (WHO) reported confirmation of the first two cases of indigenous transmission of chikungunya fever (CHIK) in the Region of the Americas on the island of Sint Maarten (Netherlands Antilles). For the period 2013-2014, a total of 25 627 confirmed autochthonous cases were distributed in 43 countries, with Mexico reporting 155 cases in five states. Information on cases of CHIK in Mexico was obtained from the database of the General Directorate of Epidemiology (Ministry of Health of Mexico). The distribution of confirmed autochthonous cases of CHIK for 2015, by sex, was 64% female (5 583) and 36% male (3 085). The most frequent symptoms were fever in 98% of cases (8 564), followed by headache in 91.6% (7 941), myalgia in 89.9% (7 792), mild arthralgias in 73.5% (6 367), severe polyarthralgia in 72.6% (6 295), and exanthema in 58% (5 032). The clinical presentation of autochthonous cases of CHIK in Mexico has shown several clinical manifestations different from those seen in outbreaks in African and Asian countries and other regions in the Americas; for example, a greater percentage of cases with headache and myalgia and a smaller percentage of cases with arthralgia.(AU)

Evidence of the presence of the Zika virus in Mexico since early 2015.

To assess the possible circulation of Zika virus (ZIKV) prior to the first documented case in Mexico, we reanalyzed the stored samples from the states of Veracruz and Yucatán, which were originally collected to test for dengue (DENV) and chikungunya (CHIKV) but were negative for these viruses despite the symptomatology. The samples were originally collected between the 30 and 46 epidemiological weeks (EW) when the ZIKV was not yet declared as a Public Health Emergency of International Concern (PHEIC). From the total 4016 negative samples, a total of one hundred samples, 50 from Veracruz (CHIK- DENV-) and 50 from Yucatán (4 CHIK- DENV- and 46 CHIK- or DENV-), were tested for Zika virus by using RT-PCR. Results showed that in Veracruz and Yucatán, 20 % (10/50) and 70 % (35/50) were, respectively, ZIKV positive, indicating unequivocally the presence of ZIKV at least since July 2015. We also tested non-confirmed suspect measles cases from early 2015 for ZIKV by RT-PCR. Remarkably in 11 Mexican states, 86 % (18/21) were positive with the earlier symptoms onset as early as May 2015. Finally, RT-PCR analyses on RNA extracted from Aedes aegypti mosquitoes captured from January to March 2015 showed the presence of ZIKV, strongly suggesting that the vector was already carrying the virus at the start of 2015.

Complete Genome Sequence of Zika Virus Isolated in Mexico, 2016.

Zika virus belongs to the genus Flavivirus, and its spread remains an international public health emergency. In this report, we describe the obtainment and molecular characterization of a complete viral genome through the direct metagenomic analysis from saliva from an autochthonous transmission case in Mexico.

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

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.

Biochemical and full genome sequence analyses of clinical Vibrio cholerae isolates in Mexico reveals the presence of novel V. cholerae strains.

The first week of September 2013, the National Epidemiological Surveillance System identified two cases of cholera in Mexico City. The cultures of both samples were confirmed as Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor. Initial analyses by PFGE and by PCR-amplification of the virulence genes, suggested that both strains were similar, but different from those previously reported in Mexico. The following week, four more cases were identified in a community in the state of Hidalgo, located 121 km northeast of Mexico City. Thereafter a cholera outbreak started in the region of La Huasteca. Genomic analyses of the four strains obtained in this study confirmed the presence of Pathogenicity Islands VPI-1 and -2, VSP-1 and -2, and of the integrative element SXT. The genomic structure of the 4 isolates was similar to that of V. cholerae strain 2010 EL-1786, identified during the epidemic in Haiti in 2010.

Identification of Asian genotype of chikungunya virus isolated in Mexico.

We identified 25 autochthonous chikungunya virus cases in Mexico, initially detected by RT-PCR targeting the E1 gene and propagated in C6/36 Aedes albopictus cells, in 2014. To determine the type of virus found, in a previous report, the genomes of 2 CHIKV strains were fully sequenced. Genome sequence analysis revealed that these isolates from Mexico belonged to the Asian genotype, and a phylogenetic association with the circulating strain in the British Virgin Islands was also established in the same year. This was further supported by changes in specific amino acids, E2-V368A and 6K-L20M. For these reasons, it can be inferred that the route of virus entry to Mexico was held across the countries in the Caribbean and Central America. The presence of E1-A226V mutation associated with more efficient replication in the salivary gland of the A. albopictus mosquito was not observed. Interestingly, a newly acquired NSP4-S399C mutation was observed; however, the significance of changes in amino acid found in non-structural proteins in autochthonous strains remains to be elucidated.

Complete genome sequences of chikungunya virus strains isolated in Mexico: first detection of imported and autochthonous cases.

The mosquito-borne chikungunya virus, an alphavirus of the Togaviridae family, is responsible for acute polyarthralgia epidemics. Here, we report the complete genome sequences of two chikungunya virus strains, InDRE04 and InDRE51, identified in the Mexican states of Jalisco and Chiapas in 2014. Phylogenetic analysis showed that both strains belong to the Asian genotype.

Genome Sequence of Vibrio cholerae Strain O1 Ogawa El Tor, Isolated in Mexico, 2013.

We present the draft genome sequence of Vibrio cholerae InDRE 3140 recovered in 2013 during a cholera outbreak in Mexico. The genome showed the Vibrio 7th pandemic islands VSP1 and VSP2, the pathogenic islands VPI-1 and VPI-2, the integrative and conjugative element SXT/R391 (ICE-SXT), and both prophages CTXφ and RS1φ.

Outbreak of Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor strain--La Huasteca Region, Mexico, 2013.

On September 2 and 6, 2013, Mexico's National System of Epidemiological Surveillance identified two cases of cholera in Mexico City. Rectal swab cultures from both patients were confirmed as toxigenic Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor. Pulsed-field gel electrophoresis and virulence gene amplification (ctxA, ctxB, zot, and ace) demonstrated that the strains were identical to one another but different from strains circulating in Mexico previously. The strains were indistinguishable from the strain that has caused outbreaks in Haiti, the Dominican Republic, and Cuba. The strain was susceptible to doxycycline, had intermediate susceptibility to ampicillin and chloramphenicol, was less than fully susceptible to ciprofloxacin, and was resistant to furazolidone and trimethoprim-sulfamethoxazole. An investigation failed to identify a common source of infection, additional cases, or any epidemiologic link between the cases. Both patients were treated with a single, 300-mg dose of doxycycline, and their symptoms resolved.

Highly pathogenic avian influenza A(H7N3) virus in poultry workers, Mexico, 2012.

We identified 2 poultry workers with conjunctivitis caused by highly pathogenic avian influenza A(H7N3) viruses in Jalisco, Mexico. Genomic and antigenic analyses of 1 isolate indicated relatedness to poultry and wild bird subtype H7N3 viruses from North America. This isolate had a multibasic cleavage site that might have been derived from recombination with host rRNA.