Suicidal Ideation and Behavior Among Mexican University Students Before and During the COVID-19 Pandemic.

OBJECTIVE: The COVID-19 pandemic has affected the mental health of populations around the world, but few longitudinal studies of its impact on suicidal thoughts and behaviors have been published especially from low- and middle-income countries. METHODS: This is a prospective cohort study of 1,385 first-year students from 5 Universities in Mexico followed-up for 1 year. We report 1-year cumulative incidence of suicidal thoughts and behaviors before (September 19, 2019-March 29, 2020) and during the COVID-19 period (March 30, 2020-June 30, 2020), focusing on those in the COVID-19 period with risk conditions and positive coping strategies during the pandemic. RESULTS: There was an increase in the incidence of suicidal ideation during the COVID-19 period compared to the pre-COVID-19 period (RR 1.65, 95%CI 1.08-2.50). This increase was mostly found among students with heightened sense of vulnerability (RR 1.95), any poor coping behavior (RR 2.40) and a prior mental disorder (RR 2.41). While we found no evidence of an increased risk of suicidal planning or attempts, there was evidence that those without lifetime mental health disorders were at greater risk of suicidal plans than those with these disorders especially if they had poor coping strategies (RR 3.14). CONCLUSION: In the short term, how students deal with the pandemic, being at high risk and having poor coping behavior, increased the new occurrence of suicidal thoughts and behaviors. Studies with longer follow-up and interventions to reduce or enhance these behaviors are needed.HIGHLIGHTSSuicidal ideation increased during the COVID-19 periodThose with heightened sense of vulnerability and poor coping were more affectedStudies with longer follow-up are needed.

Another Vision of the Situation of the COVID-19 Pandemic in Mexico During 2020.

The number of coronavirus disease 2019 (COVID-19) cases and deaths registered in Mexico during 2020 could be underestimated, due to the sentinel surveillance adopted in this country. Some consequences of following this type of epidemiological surveillance were the high case fatality rate and the high positivity rate for COVID-19 shown in Mexico in 2020. During this year, the Mexican Ministry of Health only considered cases from the public health system, which followed this sentinel surveillance, but did not consider those cases from the private health system. To better understand this pandemic, it is important to include all the results obtained by all the institutions capable of testing for COVID-19; thus, the Mexican Government could then make good decisions to protect the population from this disease.

A one-step real-time RT-PCR helps to identify mixed rotavirus infections in Mexico.

Rotaviruses continue being the most important pathogens responsible of diarrhea in young children worldwide. Seminested reverse transcription polymerase chain reaction (RT-PCR) is used to determine rotavirus genotype; however, this technique employs multistep procedures. The real-time RT-PCR is a fast and reliable tool that can be used as rotavirus genotyping tool, especially in rotavirus outbreaks. In this study, we tested a real-time RT-PCR to identify rotavirus genotype using a panel of 252 samples from patients with diarrheal disease caused by G9P[4] and G12P[8] genotypes, which were identified as emerging rotaviruses in 2 outbreaks in Chiapas, Mexico. Our results show that the real-time RT-PCR assay detected these rotaviruses, and it allowed us to identify mixed genotype infections, G/P combinations, and the viral abundance in some samples in which the seminested assay could not identify them. Therefore, the real-time RT-PCR is a molecular tool that can be great support during rotavirus outbreaks.

Real-time RT-PCR, a necessary tool to support the diagnosis and surveillance of rotavirus in Mexico.

Rotavirus produces diarrhea in children under 5 years old. Most of those conventional methods such as polyacrylamide gel electrophoresis (PAGE) and reverse transcription-polymerase chain reaction (RT-PCR) have been used for rotavirus detection. However, these techniques need a multi-step process to get the results. In comparison with conventional methods, the real-time RT-PCR is a highly sensitive method, which allows getting the results in only one day. In this study a real-time RT-PCR assay was tested using a panel of 440 samples from patients with acute gastroenteritis, and characterized by PAGE and RT-PCR. The results show that the real-time RT-PCR detected rotavirus from 73% of rotavirus-negative samples analyzed by PAGE and RT-PCR; thus, the percentage of rotavirus-positive samples increased to 81%. The results indicate that this real-time RT-PCR should be part of a routine analysis, and as a support of the diagnosis of rotavirus in Mexico.

Primary dengue virus infections induce differential cytokine production in Mexican patients.

Severe dengue pathogenesis is not fully understood, but high levels of proinflammatory cytokines have been associated with dengue disease severity. In this study, the cytokine levels in 171 sera from Mexican patients with primary dengue fever (DF) and dengue haemorrhagic fever (DHF) from dengue virus (DENV) 1 (n = 116) or 2 (n = 55) were compared. DF and DHF were defined according to the patient's clinical condition, the primary infections as indicated by IgG enzymatic immunoassay negative results, and the infecting serotype as assessed by real-time reverse transcription-polymerase chain reaction. Samples were analysed for circulating levels of interleukin (IL)-12p70, interferon (IFN)-γ, tumour necrosis factor (TNF)-α, IL-6, and IL-8 using a commercial cytometric bead array. Significantly higher IFN-γ levels were found in patients with DHF than those with DF. However, significantly higher IL-12p70, TNF-α, and IL-6 levels were associated with DHF only in patients who were infected with DENV2 but not with DENV1. Moreover, patients with DF who were infected with DENV1 showed higher levels of IL-12p70, TNF-α, and IL-6 than patients with DHF early after-fever onset. The IL-8 levels were similar in all cases regardless of the clinical condition or infection serotype. These results suggest that the association between high proinflammatory cytokine levels and dengue disease severity does not always stand, and it once again highlights the complex nature of DHF pathogenesis.

Primary dengue virus infections induce differential cytokine production in Mexican patients

Severe dengue pathogenesis is not fully understood, but high levels of proinflammatory cytokines have been associated with dengue disease severity. In this study, the cytokine levels in 171 sera from Mexican patients with primary dengue fever (DF) and dengue haemorrhagic fever (DHF) from dengue virus (DENV) 1 (n = 116) or 2 (n = 55) were compared. DF and DHF were defined according to the patient’s clinical condition, the primary infections as indicated by IgG enzymatic immunoassay negative results, and the infecting serotype as assessed by real-time reverse transcription-polymerase chain reaction. Samples were analysed for circulating levels of interleukin (IL)-12p70, interferon (IFN)-γ, tumour necrosis factor (TNF)-α, IL-6, and IL-8 using a commercial cytometric bead array. Significantly higher IFN-γ levels were found in patients with DHF than those with DF. However, significantly higher IL-12p70, TNF-α, and IL-6 levels were associated with DHF only in patients who were infected with DENV2 but not with DENV1. Moreover, patients with DF who were infected with DENV1 showed higher levels of IL-12p70, TNF-α, and IL-6 than patients with DHF early after-fever onset. The IL-8 levels were similar in all cases regardless of the clinical condition or infection serotype. These results suggest that the association between high proinflammatory cytokine levels and dengue disease severity does not always stand, and it once again highlights the complex nature of DHF pathogenesis.

A strong interferon response correlates with a milder dengue clinical condition.

BACKGROUND: Type 1 interferon (IFNα/ß) has a significant role in establishing protection against virus infections. It has been well documented by in vitro studies that dengue virus (DENV) activates a robust IFNα/ß response. However, DENV also induces a down-regulation of the JAK/STAT pathway, inhibiting the induction of interferon regulated genes. As a consequence, the role played by the IFN type 1 response in the protection of dengue patients is not fully understood. OBJECTIVE: To compare IFN-α levels in dengue patients with dengue fever (DF) or dengue hemorrhagic fever (DHF) undergoing primary or secondary infections. STUDY DESIGN: Two hundred and four serum samples were analyzed for IFN-α level by cytometric bead array. Patients' clinical condition was assigned following the WHO 1997 criteria and specific IgG and IgM antibodies were measured using commercial assays to determine primary and secondary infections. The infecting serotype was determined by qRT-PCR. RESULTS AND CONCLUSION: The IFN-α levels were found significantly higher in DF than DHF patients irrespective of the infecting serotype (DENV1 or 2), and were found to decline rapidly at day 3 after fever onset. For DENV2 infections, higher IFN-α level was found during primary than secondary infections. These results suggest that an early strong interferon response correlates with a better clinical condition.

Viral load in patients infected with dengue is modulated by the presence of anti-dengue IgM antibodies.

BACKGROUND: The measurement and detection of viremia and antigenemia in sera have been used as a marker of risk for dengue disease severity and diagnosis. However, evidence exists suggesting that levels of viremia and antigenemia are affected by the presence of specific antibodies. OBJECTIVE: To compare viral load and circulating NS1 levels in sera from patients positive or negative for dengue specific IgM antibodies. STUDY DESIGN: Three hundred and eighty serum samples were analyzed for viral load using qRT-PCR and for levels of circulating NS1 and the presence of specific antibodies using commercial EIAs. RESULTS AND CONCLUSION: Comparison of viremia levels in sera from patients positive or negative for dengue IgM antibodies showed that viral load was significantly higher (p≤0.0001) in patients negative for IgM antibodies. In contrast, levels of circulating NS1 were found unaffected by the presence of IgM (p=0.0038). Thus, dengue virus specific IgM antibodies in sera seem to be a strong negative modulator of viremia levels in patient's sera.

Determination of viremia and concentration of circulating nonstructural protein 1 in patients infected with dengue virus in Mexico.

Higher levels of viremia and circulating nonstructural protein 1 (NS1) have been associated with dengue disease severity. In this study, viremia and circulating NS1 levels were determined in 225 serum samples collected from patients in Mexico infected with dengue virus serotypes 1 and 2 (DENV-1 and DENV-2). Patients with dengue hemorrhagic fever (DHF) who were infected with DENV-1 showed higher levels of circulating NS1 than patients with dengue fever (DF) (P = 0.0175). Moreover, NS1 levels were higher in patients with primary infections with DENV-1 than in patient infected with DENV-2 (P < 0.0001) and in patients with primary infections with DENV-2 than in patients with secondary infections with DENV-2 (P = 0.0051). Unexpectedly, viremia levels were higher in patients with DF than in those with DHF infected with either DENV-1 or DENV-2 (P = 0.0019 and P = 0.001, respectively) and in patients with primary infections than those with secondary DENV-2 infections (P < 0.0001). Results indicate that levels of circulating NS1 vary according to the infecting serotype, immunologic status (primary or secondary infection), and dengue disease severity.

The 1α,25-dihydroxy-vitamin D3 reduces dengue virus infection in human myelomonocyte (U937) and hepatic (Huh-7) cell lines and cytokine production in the infected monocytes.

Dengue is the most important mosquito-borne viral infection in humans. Recent evidence suggests that vitamin D influences virus replication. In this work, the effect of vitamin D treatment on dengue virus infection in human hepatic Huh-7 cells and on virus infection and cytokine production in the human monocytic U937 cells was evaluated. Exposure to 1α,25-dihydroxy-vitamin D3, resulted in a significant reduction in the number of infected cells, in conditions where cell viability was not affected. Viral replication in monocytic cells was more susceptible to vitamin D3 than replication in the hepatic cells. Moreover, vitamin D3 significantly reduced the levels of proinflammatory cytokines (TNF-α, IL-6, IL-12p70 and IL-1ß) produced by infected U937 cells. These results suggest that vitamin D3 may represent a potentially useful antiviral compound.

Evaluation of a novel commercial rapid test for dengue diagnosis based on specific IgA detection.

The performance of the novel commercial test ASSURE® Dengue IgA Rapid test (MP Diagnostics) was evaluated using a panel of 172 sera collected from dengue patients and 47 sera from healthy blood donors. The overall specificity and sensitivity were 61.0% and 85.1%, respectively. However, the positivity rate for IgA went from 33.3% for sera collected the same day of fever onset to 81.2% for sera collected 5 days after fever onset. Infections with serotype 2 viruses were detected more efficiently than those with serotype 1 viruses, and no sera from infections with serotypes 3 and 4 were available. In addition, the kit was twice more efficient at detecting secondary infections than at detecting primary infections. Finally, the ASSURE® test showed good repeatability and reproducibility. The results of this study suggest that the ASSURE® Dengue IgA Rapid test may become a useful and easy-to-use test for early dengue diagnosis.

Serotipos de dengue en México durante 2009 y 2010 / Dengue serotypes in México during 2009-2010

Introducción. El dengue en México es un problema prioritario de salud pública. Desde el 2008 el Departamento para la Vigilancia Epidemiológica y Virológica del InDRE implementó un nuevo algoritmo de diagnóstico del dengue, que utiliza la Red de Laboratorios Estatales de Salud Pública, para favorecer la representatividad geográfica, la oportunidad, la sensibilidad y la especificidad de la información que se obtiene. Métodos. La identificación de serotipos se realizó a partir de muestras positivas a la proteína NS1 por ensayo inmunoenzimático (ELISA). Las técnicas que se utilizaron fueron: aislamiento viral, PCR punto final y, desde 2009, RT-PCR en tiempo real (qRT-PCR). Resultados. En 2009 se analizaron 6,336 muestras; en 2,944 de éstas (46.6%) se identificó el serotipo DENV-1 que predominó sobre el serotipo DENV-2; el serotipo DENV-3 sólo se identificó en dos casos en Guerrero y el serotipo DENV-4 en un caso en Chiapas. En 2010 se analizaron 2,013 muestras. Se identificó algún serotipo en 1,607 muestras (79.88%) y, nuevamente, el serotipo DENV-1 predominó en todo el país. En Chiapas se identificaron los serotipos DENV-1, 2 y 4 y en Jalisco los serotipos DENV-1 y 3. Además, se identificó la circulación del serotipo DENV-3 en Guerrero y apareció el serotipo DENV-4 en San Luis Potosí. Conclusiones. Por la selección de muestras para vigilancia virológica de dengue mediante la positividad a la proteína NS1 y por la introducción de la técnica de qRT-PCR se optimizó la identificación de serotipos circulantes. La alta endemia, los brotes en nuevas regiones, el predominio del serotipo DENV-1 por varios años y la introducción lenta de otros serotipos, principalmente DENV-3, pueden favorecer la aparición de formas clínicas graves de dengue. La vigilancia epidemiológica inteligente del dengue brindará información para un mejor entendimiento de la enfermedad y promoverá acciones para su control y prevención.

Background. Dengue is a public health priority in Mexico. Since 2008, the dengue diagnostic algorithm for epidemiological and virological surveillance has been improved at InDRE and the public health laboratory network (RLESP) to optimize geographic representation, opportunity, sensitivity and specificity of the produced information. Methods. Dengue serotype identification is based on ELISA NS1 positive samples. Methods used are viral isolation, endpoint PCR and, since August 2009, real-time PCR (qRT-PCR). Results. In 2009, 6,336 serum samples were analyzed and 2,944 (46.6%) were positive for serotype identification. DENV-1 was detected in greater proportion followed by DENV-2, and DENV-3 4 was only identified in two cases in Guerrero and DENV-4 in one case in Chiapas. In 2010, 2,013 serum samples were analyzed and 1,607 (78.8%) were positive for serotype identification. DENV-1 was predominant throughout the country. In Chiapas, DENV-1, 2 and 4 were identified and in Jalisco DENV-1 and 3. DENV-3 was identified in Guerrero again and DENV-4 was detected in San Luis Potosí. Conclusions. The selection samples through NS1 positive samples and the introduction of qRT-PCR optimized serotype identification. Hyperendemicity, outbreaks in new geographic areas, the predominant circulation of DENV-1 for several years and the slow reintroduction of the other serotypes, mainly DENV-3, could increase clinical cases of severe dengue. An ¡intelligentí epidemiological surveillance program would offer information for a better understanding of the disease and promote action for its control and prevention.