Influences of cross-border mobility on tuberculosis diagnoses and treatment interruption among injection drug users in Tijuana, Mexico

Wastewater sequencing as a powerful tool to reveal SARS-CoV-2 variant introduction and spread in French Guiana, South America

The origin of introduction of a new pathogen in a country, the evolutionary dynamics of an epidemic within a country, and the role of cross-border areas on pathogen dynamics remain complex to disentangle and are often poorly understood. For instance, cross-border areas represent the ideal location for the sharing of viral variants between countries, with international air travel, land travel and waterways playing an important role in the cross-border spread of infectious diseases. Unfortunately, monitoring the point of entry and the evolutionary dynamics of viruses in space and time within local populations remain challenging. Here we tested the efficiency of wastewater-based epidemiology and genotyping in monitoring Covid-19 epidemiology and SARS-CoV-2 variant dynamics in French Guiana, a tropical country located in South America. Our results suggest that wastewater-based epidemiology and genotyping are powerful tools to monitor variant introduction and disease evolution within a tropical country but the inclusion of both clinical and wastewater samples could still improve our understanding of genetic diversity co-circulating. Wastewater sequencing also revealed the cryptic transmission of SARS-CoV-2 variants within the country. Interestingly, we found some amino acid changes specific to the variants co-circulating in French Guiana, suggesting a local evolution of the SARS-CoV-2 variants after their introduction. More importantly, our results showed that the proximity to bordering countries was not the origin of the emergence of the French Guianese B.1.160.25 variant, but rather that this variant emerged from an ancestor B.1.160 variant introduced by European air plane travelers, suggesting thus that air travel remains a significant risk for cross-border spread of infectious diseases. Overall, we suggest that wastewater-based epidemiology and genotyping provides a cost effective and non-invasive approach for pathogen monitoring and an early-warning tool for disease emergence and spread within a tropical country.

Cocirculation and replacement of SARS-CoV-2 variants in crowded settings and marginalized populations along the US-Mexico border

OBJECTIVE

To interrogate the circulating SARS-CoV-2 lin-eages and recombinant variants in persons living in migrant shelters and persons who inject drugs (PWID).

MATERIALS AND METHODS

We combined data from two studies with marginalized populations (migrants in shelters and persons who inject drugs) in Tijuana, Mexico. SARS-CoV-2 variants were identified on nasal swabs specimens and compared to publicly available genomes sampled in Mexico and California.

RESULTS

All but 2 of the 10 lineages identified were predomi-nantly detected in North and Central America. Discrepan-cies between migrants and PWID can be explained by the temporal emergence and short time span of most of these lineages in the region.

CONCLUSION

The results illustrate the temporo-spatial structure for SARS-CoV-2 lineage dispersal and the potential co-circulation of multiple lineages in high-risk populations with close social contacts. These conditions create the potential for recombination to take place in the California-Baja California border.

South to North Migration Patterns of Tuberculosis Patients Diagnosed in the Mexican Border with Texas

The Mexican state of Tamaulipas serves as a migration waypoint into the US. Here, we determined the contribution of immigrants to TB burden in Tamaulipas. TB surveillance data from Tamaulipas (2006-2013) was used to conduct a cross-sectional characterization of TB immigrants (born outside Tamaulipas) and identify their association with TB treatment outcomes. Immigrants comprised 30.8% of TB patients, with > 99% originating from internal Mexican migration. Most migration was from South to North, with cities adjacent to the US border as destinations. Immigrants had higher odds of risk factors for TB [older age (≥ 65 year old, OR 2.4, 95% CI 2.1, 2.8), low education (OR 1.3, 95% CI 1.2, 1.4), diabetes (OR 1.2, 95% CI 1.1, 1.4)], or abandoning treatment (adjusted OR 1.2, 95% CI 1.0, 1.5). There is a need to identify strategies to prevent TB more effectively in Tamaulipas, a Mexican migration waypoint.

Latent Tuberculosis in Hematopoietic Stem Cell Transplantation: Diagnostic and Therapeutic Strategies to Prevent Disease Activation in an Endemic Population

Latent tuberculosis infection (LTBI) affects one-fourth of the world´s population. Hematopoietic stem cell transplantation (HSCT) recipients are at an elevated risk of developing active tuberculosis infection (ATBI). In this retrospective study of donors and HSCT recipients who underwent transplantation between February 2000 and June 2018, our aim was to determine the prevalence of LTBI and ATBI and to describe diagnostic and therapeutic strategies in an HSCT population in an endemic region. The cohort of 409 participants included 125 allogeneic HSCT (allo-HSCT) recipients, 165 autologous HSCT (auto-HSCT) recipients, and 119 HSCT donors. Patients were evaluated pre-HSCT with tuberculin skin test and thoracic imaging. LTBI was diagnosed in 26.2% of the cohort. Cases represented 20% of the auto-HSCT population, 20% of the allo-HSCT population, and 41.2% of the donor population. Pre-HSCT evaluation to rule out ATBI was performed in 62.6% of the cohort; all results were negative. Isoniazid was administered to 73.3% of those with LTBI. Within subgroups, 91.7% of HSCT recipients and 51% of donors received treatment. The median duration of therapy pre-HSCT was 70 days in recipients and 48 days in donors. The incidence of post-HSCT ATBI was 0 at 1-year follow-up. The incidence of LTBI in our population was higher than expected and still might have been underestimated owing to diagnostic test limitations. The absence of incident ATBI suggests that recipients, as opposed to donors, must receive LTBI treatment. Prevention of infectious complications in the HSCT population should be prioritized to improve clinical outcomes. Prospective data from collaborative working groups is needed to determine the best diagnostic and therapeutic approaches in this vulnerable patient population.

Morbidity Trends and Risk of Tuberculosis: Mexico 2007-2017

Background

To know the current status of the epidemiological and geographic distribution of tuberculosis and its complication meningeal tuberculosis in Mexico, this work analyzes national surveillance data (ten years) issued by the General Directorate of Epidemiology (GDE).

Methods

An observational and retrospective analysis of monthly and annual reports of pulmonary and meningeal tuberculosis cases from January 2007 to December 2017 was performed on the annual reports issued by the GDE in Mexico. The number of cases and incidence were classified by year, state, age group, gender, and seasons.

Results

A national case distribution map of pulmonary and meningeal tuberculosis incidence was generated. During this period, a total of 184,003 and 3,388 cases were reported with a median of 16,727.5 and 308 cases per year for pulmonary and meningeal tuberculosis diseases, respectively. The number of cases and incidence of pulmonary and meningeal tuberculosis per year showed that male gender presented a continuous increase in both parameters. The geographic analysis of the distribution of cases of tuberculosis showed that states like Guerrero, Tabasco, and Veracruz presented higher means of tuberculosis cases during this period. Northern states had the highest number of cases in the country compared to other states. In Mexico, pulmonary tuberculosis and meningeal tuberculosis are seasonal. Interestingly, cases of meningeal tuberculosis show an increase during October and November (autumn).

Conclusions

In Mexico, during the years 2007-2017, there has been an increase in the proportion of male TB patients. It remains necessary to implement strategies to detect TB in the adult population, especially among men, because tuberculosis could be difficult to recognize in an early stage in the population, and the appearance of resistant strains can cause an increase in the incidence of the disease.

Mycobacterium tuberculosis infection among persons who inject drugs in San Diego, California

BACKGROUND

Persons who inject drugs (PWID) might be at increased risk for Mycobacterium tuberculosis infection and reactivation of latent tuberculous infection (LTBI) due to their injection drug use.

OBJECTIVES

To determine prevalence and correlates of M. tuberculosis infection among PWID in San Diego, California, USA.

METHODS

PWID aged 18 years underwent standardized interviews and serologic testing using an interferon-gamma release assay (IGRA) for LTBI and rapid point-of-care assays for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infections. Independent correlates of M. tuberculosis infection were identified using multivariable log-binomial regression.

RESULTS

A total of 500 participants met the eligibility criteria. The mean age was 43.2 years (standard deviation 11.6); most subjects were White (52%) or Hispanic (30.8%), and male (75%). Overall, 86.7% reported having ever traveled to Mexico. Prevalence of M. tuberculosis infection was 23.6%; 0.8% were co-infected with HIV and 81.7% were co-infected with HCV. Almost all participants (95%) had been previously tested for M. tuberculosis; 7.6% had been previously told they were infected. M. tuberculosis infection was independently associated with being Hispanic, having longer injection histories, testing HCV-positive, and correctly reporting that people with 'sleeping' TB cannot infect others.

CONCLUSIONS

Strategies are needed to increase awareness about and treatment for M. tuberculosis infection among PWID in the US/Mexico border region.

Detection of latent tuberculosis infection among migrant farmworkers along the US-Mexico border

Background

Migrant farmworkers are among the highest-risk populations for latent TB infection (LTBI) in the United States with numerous barriers to healthcare access and increased vulnerability to infectious diseases. LTBI is usually diagnosed on the border using the tuberculin skin test (TST). QuantiFERON-TB Gold In-Tube (QFT-GIT) also measures immune response against specific Mycobacterium tuberculosis antigens. The objective of this study is to assess the comparability of TST and QFT-GIT to detect LTBI among migrant farmworkers on the border, as well as to examine the effects of various demographic and clinical factors on test positivity.

Methods

Participants were recruited using mobile clinics on the San Luis US-Mexico border and tested with QFT-GIT and TST. Demographic profiles and clinical histories were collected. Kappa coefficients assessed agreement between TST and QFT-GIT using various assay cutoffs. Logistic regression examined factors associated with positive TST or QFT-GIT results.

Results

Of 109 participants, 59 of 108 (55 %) were either TST (24/71, 34 %) or QFT-GIT (52/106, 50 %) positive. Concordance between TST and QFT-GIT was fair (71 % agreement, ĸ = 0.38, 95 % CI: 0.15, 0.61). Factors associated with LTBI positivity included smoking (OR = 1.26, 95 % CI–1.01–1.58) and diabetes/high blood sugar (OR = 0.70, 95 % CI = 0.51–0.98).

Discussion

Test concordance between the two tests was fair, with numerous discordant results observed. Greater proportion of positives detected using QFT-GIT may help avoid LTBI under-diagnosis. Assessment of LTBI status on the border provides evidence whether QFT-GIT should replace the TST in routine practice, as well as identifies risk factors for LTBI among migrant populations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1959-3) contains supplementary material, which is available to authorized users.

[Effectiveness in the diagnosis of tuberculosis in Foz do Iguaçu, the triple-border area of Brazil, Paraguay and Argentina]

This study sought to assess the effectiveness of health services in the diagnosis of tuberculosis in Foz do Iguaçu-PR, the triple border region of Brazil, Paraguay, and Argentina. In this epidemiologic, cross-sectional study, 101 persons with tuberculosis were interviewed in 2009 by using an instrument based on the Primary Care Assessment Tool . The analysis was based on proportions and respective 95% confidence intervals (95%) and means. Emergency units (37%) and primary health care units (26%) were the most sought units. Access to medical consultation on the same day reached 70%, but tuberculosis was suspected in less than 47% of patients; bacilloscopy was conducted in 50% of patients. We conclude that although these services provide rapid care, they do not determine the true diagnosis and lead the patient to seek specialized services. Specialty services are more effective in establishing the correct diagnosis. In the triple border region, seeking care at a primary health care unit led to extra time and more returns to the hospital for a tuberculosis diagnosis.

Mortality trends and risk of dying from pulmonary tuberculosis in the 7 socioeconomic regions and the 32 States of Mexico, 2000-2009

INTRODUCTION

Tuberculosis (TB) is a world public health problem that still has a high morbidity and mortality rate mainly in countries with significant wealth gaps. Poverty, malnutrition, HIV infection, drug resistance, diabetes and addictions (mainly alcoholism) have been seen to contribute to the persistence of TB as an important health problem in Mexico.

METHODS

Death certificates associated with pulmonary tuberculosis (PTB) for 2000-2009 were obtained from the National Information System of the Secretariat of Health. Rates of mortality nationwide, by state, and by socioeconomic region were calculated. The strength of association between states where individuals resided, socioeconomic regions, and education with mortality from PTB was determined.

RESULTS

Age-adjusted mortality rates per 100,000 inhabitants who died from PTB decreased from 4.1 to 2 between 2000 and 2009. Men (67.7%) presented higher mortality than women (32.3%). Individuals failing to complete elementary education presented a higher risk of dying from PTB (RR 1.08 [95%CI: 1.05-1.12]). The socioeconomic region and the entities with the strongest association were region 1, 5, Chiapas and Baja California. Region 1 in 2007 presented RR 7.34 (95%CI: 5.32-10.13), and region 5 in 2009 had RR 10.08 (95%CI: 6.83-14.88).

CONCLUSIONS

In Mexico, the annual mortality rate from PTB decreased. Men presented higher mortality than women. Individuals failing to complete elementary education showed a higher risk of dying from PTB. The states and regions of Mexico that presented a stronger association with mortality from PTB were Chiapas and Baja California, region 1 and 5.

Healthcare provider perspectives on barriers to HIV-care access and utilisation among Latinos living with HIV in the US-Mexico border

Latinos living with HIV residing in the US-Mexico border region frequently seek care on both sides of the border. Given this fact, a border health perspective to understanding barriers to care is imperative to improve patient health outcomes. This qualitative study describes and compares experiences and perceptions of Mexican and US HIV care providers regarding barriers to HIV care access for Latino patients living in the US-Mexico border region. In 2010, we conducted in-depth qualitative interviews with HIV care providers in Tijuana (n = 10) and San Diego (n = 9). We identified important similarities and differences between Mexican and US healthcare provider perspectives on HIV care access and barriers to service utilisation. Similarities included the fact that HIV-positive Latino patients struggle with access to ART medication, mental health illness, substance abuse and HIV-related stigma. Differences included Mexican provider perceptions of medication shortages and US providers feeling that insurance gaps influenced medication access. Differences and similarities have important implications for cross-border efforts to coordinate health services for patients who seek care in both countries.

A tuberculosis outbreak fueled by cross-border travel and illicit substances: Nevada and Arizona

OBJECTIVES

From May 2006 to August 2008, the Southern Nevada Health District identified eight tuberculosis (TB) cases in six adults and two children in a Hispanic community. We conducted an outbreak investigation to determine the extent of TB transmission and prevent additional cases.

METHODS

We investigated TB cases in Nevada and Arizona with the outbreak genotype or cases with suspected epidemiologic links to this cluster but without genotyping data. We reviewed medical records and interviewed patients and contacts. Subsequently, genotype surveillance was conducted for approximately four years to monitor additional outbreak-related cases.

RESULTS

Eight outbreak cases were identified among six adults and two children. All patients were Hispanic and five were U.S.-born. The index patient was diagnosed while detained in Immigration and Customs Enforcement custody but deported before treatment completion. He was lost to follow-up for two years, during which time he served as the source for six secondary TB cases, including his own child. Along with the index patient, five patients reportedly engaged in the sale or use of methamphetamine. Follow-up surveillance in the two states identified eight additional cases with the outbreak genotype; three had epidemiologic links to the index case.

CONCLUSIONS

We found that incomplete TB treatment led to extensive TB transmission. We recommend thorough discharge planning and active measures to ensure continuity of care and TB treatment completion for people in custody at higher risk for loss to follow-up, which likely includes those engaged in the sale or use of illicit substances.

Choosing sides: HIV health care practices among shared populations of HIV-positive Latinos living near the US-Mexico border

BACKGROUND

We compared HIV-positive patients receiving care in the border cities of San Diego, United States, with Tijuana, Mexico.

METHODS

Participants were HIV-positive Latinos (n = 233) receiving antiretroviral therapy (ART) from San Diego-Tijuana clinics (2009-2010). Logistic regression identified correlates of receiving HIV care in San Diego versus Tijuana.

RESULTS

Those with their most recent HIV visit in San Diego (59%) were more likely to be older, have at least a high school education, and were less likely to have been deported than those with last visits in Tijuana. Despite reporting better patient-provider relationships and less HIV-related stigma than those with visits in Tijuana, San Diego patients were twice as likely to make unsupervised changes in their ART regimen.

CONCLUSIONS

We observed poorer relative adherence among HIV-positive Latinos receiving care in San Diego, despite reports of good clinical relationships. Further study is needed to ascertain underlying reasons to avoid ART-related resistance.

Border crossing to inject drugs in Mexico among injection drug users in San Diego, California

We examined correlates of ever injecting drugs in Mexico among residents of San Diego, California. From 2007 to 2010, injecting drug users (IDUs) in San Diego underwent an interviewer-administered survey. Logistic regression identified correlates of injection drug use in Mexico. Of 302 IDUs, 38% were Hispanic, 72% male and median age was 37; 27% ever injected in Mexico; 43% reported distributive syringe sharing there. Factors independently associated with ever injecting drugs in Mexico included being younger at first injection, injecting heroin, distributive syringe sharing at least half of the time, and transporting drugs over the last 6 months. One-quarter of IDUs reported ever injecting drugs in Mexico, among whom syringe sharing was common, suggesting possible mixing between IDUs in the Mexico-US border region. Prospective studies should monitor trends in cross-border drug use in light of recent Mexican drug policy reforms partially decriminalizing drug possession.

[Tuberculosis transmission in the triple border region: Brazil, Paraguay, and Argentina]

Tuberculosis is a public health problem in South America, but numerous control strategies have proven ineffective in settings with intense transmission. This study aimed to determine whether the triple border region between Brazil, Argentina, and Paraguay is an area of high tuberculosis transmission. An ecological study was conducted with incidence data and population estimates for the three countries. Mean incidence rates were calculated for 2001 to 2007. Spatial analysis techniques identified high-incidence areas in the region using maps with Bayesian smoothing of rates and spatial averages. During the target period, Foz do Iguaçu, Brazil, had the highest incidence, followed by Ciudad del Este in Paraguay, and Puerto Iguazú in Argentina. The analysis showed a spatial cluster of municipalities with high tuberculosis risk in the triple border region. Tuberculosis in the tri-border area shows increasing or stable incidence rates and municipalities with incidence rates above the State average. The area has high tuberculosis incidence and therefore heavy transmission of the disease.