Dynamics and Dispersal of Local Human Immunodeficiency Virus Epidemics Within San Diego and Across the San Diego-Tijuana Border.

BACKGROUND: Evolutionary analyses of well-annotated human immunodeficiency virus (HIV) sequence data can provide insights into viral transmission patterns and associated factors. Here, we explored the transmission dynamics of the HIV-1 subtype B epidemic across the San Diego (US) and Tijuana (Mexico) border region to identify factors that could help guide public health policy. METHODS: HIV pol sequences were collected from people with HIV in San Diego County and Tijuana between 1996-2018. A multistep phylogenetic approach was used to characterize the dynamics of spread. The contributions of geospatial factors and HIV risk group to the local dynamics were evaluated. RESULTS: Phylogeographic analyses of the 2034 sequences revealed an important contribution of local transmission in sustaining the epidemic, as well as a complex viral migration network across the region. Geospatial viral dispersal between San Diego communities occurred predominantly among men who have sex with men, with central San Diego being the main source (34.9%) and recipient (39.5%) of migration events. HIV migration was more frequent from San Diego county towards Tijuana than vice versa. Migrations were best explained by the driving time between locations. CONCLUSIONS: The US-Mexico border may not be a major barrier to the spread of HIV, which may stimulate coordinated transnational intervention approaches. Whereas a focus on central San Diego has the potential to avert most spread, the substantial viral migration independent of central San Diego shows that county-wide efforts will be more effective. Combined, this work shows that epidemiological information gleaned from pathogen genomes can uncover mechanisms that underlie sustained spread and, in turn, can be a building block of public health decision-making.

HIV pretreatment drug resistance trends in three geographic areas of Mexico.

BACKGROUND: Pretreatment drug resistance (PDR) levels to NNRTI approaching 10% have recently been reported in Mexico. However, subnational differences may exist in PDR prevalence and transmission dynamics. OBJECTIVES: We longitudinally assessed HIV PDR in three geographic areas of Mexico. PATIENTS AND METHODS: HIV-infected, antiretroviral-naive individuals were recruited from 2008 to 2016, from the Central Metropolitan Zone (CMZ), Cancun and Tijuana (1194, 773 and 668 respectively). PDR was estimated using the Stanford HIVdb tool from plasma HIV pol sequences. RESULTS: A higher proportion of females, lower education and lower employment rate were observed in Tijuana, while a higher proportion of MSM was observed in the CMZ (P < 0.0001, all cases). For 2012-16, PDR was 13.4%, 8.9% and 11.2% in the CMZ, Tijuana and Cancun respectively. NNRTI PDR was highest in the three regions (8.7%, 4.8% and 8.1% respectively, P < 0.05); nevertheless, NNRTI PDR in Tijuana was lower than in the CMZ (P = 0.01). For 2008-16, we observed increasing efavirenz resistance trends in all regions (P < 0.05, all cases), reaching 11.8%, 6.1% and 8.3% respectively in 2016. Increasing efavirenz resistance was mostly associated with increasing K103N frequency (P = 0.007 CMZ, P = 0.03 Tijuana, not significant for Cancun). CONCLUSIONS: Our study suggests different NNRTI PDR prevalence and transmission dynamics in three geographical areas of Mexico. Even when increasing trends in efavirenz resistance were observed in the three areas, our observations support that, in a large country such as Mexico, subnational surveillance and locally tailored interventions to address drug resistance may be a reasonable option.

The Gender Minority Stress and Resilience Measure: Psychometric Validity for Use in Spanish.

Purpose: Stigma is a fundamental driver of HIV disparities among transgender women (TW). The gender minority stress and resilience (GMSR) measure has not been validated in Spanish-speaking, resource-limited settings. We examined the psychometric properties of a translated and abbreviated GMSR among TW in Tijuana, Mexico. Methods: From 2020 to 2021, 152 participants were recruited through social media and venue-based sampling. We collected information on the abbreviated GMSR, psychosocial factors (e.g., depressive symptoms), and sociodemographics. The abbreviated GMSR assessed 7 factors (Discrimination, Rejection, Internalized Transphobia, Negative Expectations, Nondisclosure, Pride, and Community Connectedness). Confirmatory factor analysis, Cronbach's alphas, and McDonald's omegas assessed structural validity. Pearson's partial correlations assessed criterion, convergent, and discriminant validities. Results: The 7-factor structure solution had acceptable fit (root mean square error of approximation [95% confidence interval]=0.05 [0.05-0.06]; comparative fit index/Tucker-Lewis index=0.92/0.91); and internal reliability (α=0.62-0.89; ω=0.62-0.89). Depressive (r=0.22-0.43; p<0.001-0.007), post-traumatic stress disorder (PTSD; r=0.20-0.34; p<0.001-0.017) symptoms, and perceived stress (r=0.19-0.41; p≤0.001-0.030) were all positively associated with all stress factors (e.g., Discrimination, Rejection, Internalized Transphobia, Negative Expectations, and Nondisclosure). The resilience factor Pride was associated with fewer PTSD symptoms (r=-0.18; p=0.027), lower perceived life stress (r=-0.21; p=0.012), and greater general resilience (r=0.26; p=0.002). The Community Connectedness resilience factor was associated with fewer depressive symptoms (r=-0.22; p=0.007). Constructs were conceptually distinct with factor correlations below 0.60. Conclusion: Findings suggest that the Spanish-translated, abbreviated GMSR is a reliable and valid measure. These data expand the usability of the GMSR to TW in a Latin American, Spanish-speaking context.

Effective Treatment of Patients Experiencing Primary, Acute HIV Infection Decreases Exhausted/Activated CD4+ T Cells and CD8+ T Memory Stem Cells.

Several studies have identified main changes in T- and B-lymphocyte subsets during chronic HIV infection, but few data exist on how these subsets behave during the initial phase of HIV infection. We enrolled 22 HIV-infected patients during the acute stage of infection before the initiation of antiretroviral therapy (ART). Patients had blood samples drawn previous to ART initiation (T0), and at 2 (T1) and 12 (T2) months after ART initiation. We quantified cellular HIV-DNA content in sorted naïve and effector memory CD4 T cells and identified the main subsets of T- and B-lymphocytes using an 18-parameter flow cytometry panel. We identified correlations between the patients' clinical and immunological data using PCA. Effective HIV treatment reduces integrated HIV DNA in effector memory T cells after 12 months (T2) of ART. The main changes in CD4+ T cells occurred at T2, with a reduction of activated memory, cytolytic and activated/exhausted stem cell memory T (TSCM) cells. Changes were present among CD8+ T cells since T1, with a reduction of several activated subsets, including activated/exhausted TSCM. At T2 a reduction of plasmablasts and exhausted B cells was also observed. A negative correlation was found between the total CD4+ T-cell count and IgM-negative plasmablasts. In patients initiating ART immediately following acute/early HIV infection, the fine analysis of T- and B-cell subsets has allowed us to identify and follow main modifications due to effective treatment, and to identify significant changes in CD4+ and CD8+ T memory stem cells.

Clinical, Imaging, and Laboratory Characteristics of Adult Mexican Patients with Tuberculous Meningitis: A Retrospective Cohort Study.

Tuberculous Meningitis (TBM) is the most common form of central nervous system Tuberculosis (TB), accounting for 5-6% of extrapulmonary TB cases. Nowadays, TBM continues to be a major topic in public health because of its high prevalence worldwide. This retrospective study aimed to describe the clinical, laboratory, and imaging characteristics at admission; and in-hospital outcome of adult Mexican patients with TBM. We collected data from medical records of patients aged ≥18 years diagnosed with TBM according to the uniform case definition for clinical research who were treated at Tijuana General Hospital between January 2015 and March 2018 and compared them according to the subtype of diagnosis. We included 41 cases (26 males, median age 28 years, range 18-57 years), 13 (31.7%) patients were HIV positive, and 21 (51.2%) were illicit drug users. At admission, 7 (17.1%) patients were in stage I, 22 (53.6%) in stage II, and 12 (29.3%) in stage III. A definitive diagnosis was established in 23 (56.1%) patients, probable in 14 (34.1%), and possible in four (9.8%). Molecular testing was positive in 83% of the cases, yielding significantly higher positive results than other microbiological studies. There were eight (19.5%) deaths, without statistical difference between mortality and not having a definitive diagnosis (p = 0.109). We found that the baseline characteristics of our population were similar to those described by other authors worldwide. In this series, molecular testing showed to be very useful when used in the early stages, particularly in subjects with subacute onset of headache, fever, weight loss, and altered mental status.

An outbreak of serogroup C (ST-11) meningococcal disease in Tijuana, Mexico.

BACKGROUND: Invasive meningococcal disease (IMD) has been reported to be endemic in children from Tijuana, Mexico and the risk of an outbreak was always a threat. OBJECTIVES: To describe all clinical, epidemiological and microbiological features of a meningococcal outbreak that occurred in Tijuana, Mexico. METHODS: All cases with IMD were admitted at different emergency departments within the city and diagnosed by culture and agglutination tests. Further restriction fragment length polymorphism pulse field gel electrophoresis (RFLP-PFGE) and multi locus sequence typing (MLST) were performed. All clinical and epidemiological characteristics and interventions were evaluated, as well as risk factors associated with mortality. RESULTS: From 30 January 2013 to 30 March 2013 there were 19 cases of IMD all caused by Neisseria meningitidis serogroup C. The median age was 16 years (2-47), with higher frequency among individuals at least 13 years old (73.7%). At admission, meningitis was the main clinical presentation (94.7%), followed by purpura (78.9%), septic shock (42.1%) and disseminated intravascular coagulation (DIC, 36.8%). Overall mortality was seven (36.8%). Variables associated with higher mortality were, at admission, presence of septic shock, DIC and thrombocytopenia less than 70,000. All 19 cases had no identifiable site or cluster as the source of the outbreak. RFLP-PFGE showed a discriminatory power for only one profile on all N. meningitidis strains analyzed and a clone ST-11 was identified in all strains. Public health interventions were continuous case reporting of all suspected cases of IMD, an increase in active surveillance in all hospitals, training of medical and laboratory personnel, massive and rapid chemoprophylaxis to all close contacts as indicated, and promotion of good health habits. CONCLUSIONS: An outbreak with high mortality of IMD occurred in Tijuana, Mexico. This event and evidence of endemicity should encourage health authorities to evaluate meningococcal vaccination in the region.

Pneumococcal disease: emergence of serotypes 19A and 7F following conjugate pneumococcal vaccination in a Mexican hospital.

INTRODUCTION: Mexico was the country to initiate massive vaccination with heptavalent pneumococcal conjugate vaccine (PCV-7) in children. There is no information regarding pneumococcal invasive disease (PID) in children before and after implementation of PCV-7 in Mexico or elsewhere in Latin America. METHODOLOGY: During October 2005 to September 2010, active surveillance for pediatric PID was initiated at Tijuana General Hospital. Only culture-confirmed cases from sterile fluids were included in the study. Serotype identification was also performed. RESULTS: Twenty-eight pediatric PID cases were confirmed. Streptococcus pneumoniae was the main cause of pleural empyema (n = 13). It was also the second most common cause of confirmed bacterial meningitis (n = 10), followed by Neisseria meningitidis (n = ?), and the only cause of otomastoiditis with bacterial isolation (n = 5). Vaccine-associated serotypes decreased from 54% before PCV-7 introduction to the vaccination schedule, to only 5.6% after PCV-7 implementation. Serotypes 19A and 7F (47% and 33% respectively were predominant following PCV-7 vaccination. CONCLUSIONS: Serotype substitution in PID is present in the northern border of Mexico following PCV-7 vaccination in children.

National prevalence and trends of HIV transmitted drug resistance in Mexico.

BACKGROUND: Transmitted drug resistance (TDR) remains an important concern for the management of HIV infection, especially in countries that have recently scaled-up antiretroviral treatment (ART) access. METHODOLOGY/PRINCIPAL FINDINGS: We designed a study to assess HIV diversity and transmitted drug resistance (TDR) prevalence and trends in Mexico. 1655 ART-naïve patients from 12 Mexican states were enrolled from 2005 to 2010. TDR was assessed from plasma HIV pol sequences using Stanford scores and the WHO TDR surveillance mutation list. TDR prevalence fluctuations over back-projected dates of infection were tested. HIV subtype B was highly prevalent in Mexico (99.9%). TDR prevalence (Stanford score>15) in the country for the study period was 7.4% (95% CI, 6.2∶8.8) and 6.8% (95% CI, 5.7∶8.2) based on the WHO TDR surveillance mutation list. NRTI TDR was the highest (4.2%), followed by NNRTI (2.5%) and PI (1.7%) TDR. Increasing trends for NNRTI (p = 0.0456) and PI (p = 0.0061) major TDR mutations were observed at the national level. Clustering of viruses containing minor TDR mutations was observed with some apparent transmission pairs and geographical effects. CONCLUSIONS: TDR prevalence in Mexico remains at the intermediate level and is slightly lower than that observed in industrialized countries. Whether regional variations in TDR trends are associated with differences in antiretroviral drug usage/ART efficacy or with local features of viral evolution remains to be further addressed.