Evolution of incidence and geographical distribution of Chagas disease in Mexico during a decade (2007-2016)

First Report of Seropositivity to Trypanosoma cruzi in Mexican Afro-Descendants from Guerrero and Oaxaca States

Mexican Afro-descendant is a population poorly studied in many aspects, between them the infectious diseases that they suffer. This population is mainly found in the country's Pacific (Oaxaca and Guerrero states) and Atlantic (Veracruz) coast. In these regions, a diversity of triatomine vectors of the Chagas disease is found. Also, all the genotypes of Trypanosoma cruzi DTUs have been reported. That is why the present study aimed to study the presence of antibodies against T. cruzi and cardiac pathology associated with the Chagas disease in the Mexican Afro-descendant population of Guerrero and Oaxaca. ELISA, Western blot, and recombinant antigen's ELISA were used to evaluate the seropositivity of these communities. Furthermore, an electrocardiographic study and evaluation of risk factors associated with T. cruzi infection in the Oaxaca and Guerrero populations were conducted. 26.77% of the analyzed population was positive for two serological tests. These percentages are higher than the previously reported for the mestizo population in similar studies. Electrocardiographic results showed cardiac disorder associated with the Chagas disease in the population. Also, risk factors were identified associated with the men's activities in the outdoor working areas.

Severe Chagas disease in Ecuador: a countrywide geodemographic epidemiological analysis from 2011 to 2021

Background

Chagas disease is a neglected and often forgotten tropical disease caused by the Trypanosoma cruzi. This parasite can be transmitted through the direct contact of human skin with feces and urine of the triatomine insect. According to the World Health Organization (WHO), an estimated 6-7 million people are infected worldwide, killing at least 14,000 every year. The disease has been reported in 20 of the 24 provinces of Ecuador, with El Oro, Guayas, and Loja being the most affected.

Methodology

We analyzed the morbidity and mortality rates of severe Chagas disease in Ecuador on a nationwide, population-based level. Hospitalization cases and deaths were also examined based on altitude, including low (< 2,500 m) and high (> 2,500 m) altitudes, according to the International Society. Data was retrieved from the National Institute of Statistics and Census hospital admissions and in-hospital mortality databases from 2011 to 2021.

Results

A total of 118 patients have been hospitalized in Ecuador since 2011 due to Chagas disease. The overall in-hospital mortality rate was 69.4% (N = 82). Men have a higher incidence rate (4.8/1,000,000) than women, although women have a significantly higher mortality rate than men (6.9/1,000,000).

Conclusion

Chagas disease is a severe parasitic condition that primarily affects rural and poorer areas of Ecuador. Men are more likely to be infected due to differences in work and sociocultural activities. Using average elevation data, we conducted a geodemographic analysis to assess incidence rates by altitude. Our findings indicate that the disease is more common at low and moderate altitudes, but recent increases in cases at higher altitudes suggest that environmental changes, such as global warming, could be driving the proliferation of disease-carrying vectors in previously unaffected areas.

Seroprevalence of Trypanosoma cruzi in Eight Blood Banks in Mexico

BACKGROUND

The true prevalence of Chagas disease in Mexico is unknown. However, it has been estimated that 1.1-4 million people are infected with Trypanosoma cruzi, which represents a potential risk for transmission of the disease via contaminated blood.

AIM OF THE STUDY

To determine the Chagas disease seroprevalence in donors from eight blood banks in the north of Mexico City, and the northeast of the State of Mexico.

STUDY DESIGN AND METHODS

Serum samples from blood donors (n = 515,038) were tested to detect the presence of anti-Trypanosoma cruzi antibodies in eight blood banks. The serologic screening test was performed in each of the blood banks. To confirm the seropositive blood donors, only two out of the eight blood banks used a test with a different principle with the aim of identifying anti-Trypanosoma cruzi antibodies. All tests were validated by the Mexican Institute for Epidemiological Diagnosis and Reference.

RESULTS

One thousand two hundred and ten blood donors were seropositive for Trypanosoma cruzi, which represents a 0.23% seroprevalence (95% CI 0.22-0.25%). Of the seropositive blood donors, 97.03 % resided in the northeast area of the State of Mexico, Mexico City, and southern part of the State of Hidalgo.

CONCLUSIONS

Active transmission of Chagas disease may be occurring in non-endemic regions in the northeast of the State of Mexico.

Multiple Discrete Typing Units of Trypanosoma cruzi Infect Sylvatic Triatoma dimidiata and Panstrongylus rufotuberculatus in Southeast Mexico

Chagas disease or American trypanosomiasis is an infection caused by the parasite Trypanosoma cruzi. According to its genetic characteristics, this parasite is divided into six groups (TcI-TcVI) called discrete typing units (DTUs). Trypanosoma cruzi is transmitted to humans by insects of the Triatominae family. In Mexico, despite having a great variety of triatomine species, little is known about vector sylvatic populations and the DTUs associated with them. In this work, molecular markers such as minicircle, miniexon, 18S, and 24S ribosomal genes and restriction fragment length polymorphism (RFLP) analysis of the hsp70 gene were used to determine the DTUs present in vectors from rural communities and sylvatic areas inside the Biosphere Reserve Los Tuxtlas, Veracruz, in southeast Mexico. One hundred triatomines were collected and two species were identified: Triatoma dimidiata and Panstrongylus rufotuberculatus. The infection with T. cruzi was determined in 29% of analyzed vectors from the domestic area and TcI was the predominant DTU. Furthermore, 71% of vectors from the sylvatic environment were infected and TcI, TcII, TcIV, and TcVI were identified. One female and one male of P. rufotuberculatus were infected only with TcI. This is the first report of TcVI in T. dimidiata from the sylvatic area in México and the first report of P. rufotuberculatus infected with T. cruzi in Mexico.

Trends of Seroprevalence of Chagas´s diseases in healthy blood donors, solid organ donors and heart transplant recipients: experience of a single health care center in Colombia

The prevalence of Chagas disease has decreased in the Americas region due to vector control measures. However, non-vectorial transmission through blood transfusions and organ transplantation has gained importance in recent years. Screening among blood and organ donors are essential to reduce Trypanosoma cruzi transmission and could provide information to estimate population prevalence. We conducted a cross-sectional study on the prevalence of immunoglobulin G (IgG) antibodies against T. cruzi in healthy blood donors, solid organ donors and heart transplant recipients from 2012 to 2019. We found a total of 99 357 IgG T. cruzi results during the study period. The cumulative seroprevalence in healthy blood donors was 0.13% (95% confidence interval (CI) 0.10–0.15), in organ donors was 0.53% (95% CI 0.06–1.92) and in heart transplant recipients was 3.03 (95% CI 0.07–15.75). Seroprevalence trend in healthy blood donors showed annual increase between 2012 and 2015, decreasing in the following years. No trend was seen in organ donors neither heart recipients. Adjusted rates did not show difference by sex and age among blood donors. No significant increases in seroprevalence T. cruzi were found during the study period. T. cruzi transmission remains low.

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.