Domestic Dogs as Sentinels for West Nile Virus but not Aedes-borne Flaviviruses, Mexico.

We tested 294 domestic pet dogs in Mexico for neutralizing antibodies for mosquito-borne flaviviruses. We found high (42.6%) exposure to West Nile virus in Reynosa (northern Mexico) and low (1.2%) exposure in Tuxtla Gutierrez (southern Mexico) but very limited exposure to Aedes-borne flaviviruses. Domestic dogs may be useful sentinels for West Nile virus.

Factors Associated With Extrapulmonary Tuberculosis in Southeastern Mexico: A Case-Control Study.

INTRODUCTION: Extrapulmonary tuberculosis (EPTB) is a disease that can affect any organ or tissue. Due to its potential to cause more dangerous sequelae and the barriers to its timely diagnosis, greater clinical awareness of this disease is crucial. This study aimed to identify the factors associated with EPTB in the population of Oaxaca, Mexico. METHODS: This is an unpaired case-control study. The cases were patients with EPTB+ while the controls were patients with pulmonary tuberculosis (PTB+) registered in the Tuberculosis Epidemiological Surveillance System. Sociodemographic, clinical, and microbiological variables were recovered. Bivariate analyses were performed and logistic regression analyses were performed to calculate the odds ratio (OR). RESULTS: A total of 75 EPTB+ cases and 300 PTB+ controls were included. Of the total sample, 57.1% were men and 60.3% indigenous. The most frequent clinical presentations of EPTB+ were nodal (21.3%), miliary (21.3%), and breast (20.0%). According to logistic regression analysis, age <40 years (OR: 2.25 (95% CI: 1.13-4.49), female sex (OR: 1.92 (95% CI: 1.03-3.56)], urban residence (OR: 2.25 (95% CI: 1.11-4.55)), comorbidity with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) (OR: 3.46 (95% CI: 1.31-9.10)), dyspnea (OR: 2.67 (1.22-5.82)), and adenopathy (OR: 3.38 (95% CI: 1.42-8.06)) were positively associated with EPTB+. CONCLUSION: These results can serve as a basis for screening EPTB+, thus improving the preventive and diagnostic capacity of local health services, taking as a starting point women under 40 years of age and patients with HIV/AIDS in urban areas, as well as the presence of adenopathy and dyspnea as clinical characteristics of the disease.

First report of mixed Trypanosoma cruzi discrete typing units infection in Triatoma phyllosoma in the peri-urban environment of Oaxaca, Mexico.

BACKGROUND: Chagas disease, a zoonosis transmitted mainly by hematophagous insects of the subfamily Triatominae, is caused by Trypanosoma cruzi, classified into six discrete typing units (DTUs: TcI-TcVI and Tcbat). METHODS: Insect vectors were collected from 84 human dwellings in the municipality of Santo Domingo Tehuantepec, Oaxaca, Mexico; 4.76% were infested. DTUs were determined using conventional and nested PCR. RESULTS: The infection rate was 43.6%. All insects were infected with TcI while one specimen showed mixed infection with TcII. CONCLUSIONS: This is the first report of T. cruzi mixed infection in Triatoma phyllosoma, its main vector in the study region.

Domestic Dog Infection with Trypanosoma cruzi from Northern and Southern Regions of Mexico.

Background: Chagas disease or American trypanosomiasis, caused by Trypanosoma cruzi and vectored by triatomines, affects millions of people worldwide. In endemic countries including Mexico, infections in domestic animals, such as dogs, may affect the risk of human disease when they serve as a source of infection to vectors that subsequently infect humans. Materials and Methods: We conducted a cross-sectional study of 296 dogs from two cities near the northern and southern borders of Mexico: Reynosa, Tamaulipas, and Tuxtla Gutierrez, Chiapas. Infection was measured based on testing of blood using T. cruzi quantitative PCR (qPCR) and up to three antibody detection assays. The StatPak immunochromatographic assay was used to screen samples and the indirect fluorescent antibody (IFA) and multiplex microsphere immunoassay (MIA) tests were used as secondary tests on all samples that screened positive and a subset of negatives. Serologic positivity was defined based on reactivity on at least two independent tests. Results: Of the 280 samples tested for parasite DNA, two (0.7%) were positive, one of which (0.4%) was confirmed as T. cruzi discrete typing unit TcIV. Overall, 72 (24.3%) samples were reactive for T. cruzi antibodies via StatPak of which 8 were also positive using MIA and 2 were also positive using IFA (including one of the PCR-positive dogs). Overall, nine dogs (3.4%) met study criteria of positivity based on either/both serology or PCR tests. Positive dogs were found in both regions of Mexico; five (2.7%) from Reynosa and four (3.6%) from Tuxtla Gutierrez. We found no association between infection status and state of origin, sex, age group, breed group, neighborhood, and whether other pets lived in the home. Conclusion: Our results re-emphasize dogs' utility as sentinels for T. cruzi in Mexico and underscore the need for improved veterinary diagnostic tests and parasite surveillance at the household level in endemic countries.

First Report of Eratyrus cuspidatus (Hemiptera: Reduviidae) Infected with Trypanosoma cruzi in Peridomestic Environment in Chiapas, Mexico.

Background: Triatomine bugs are natural vectors of Trypanosoma cruzi, which causes Chagas disease or American trypanosomiasis. The role of sylvatic triatomine species as vectors of T. cruzi in Mexico remains to be fully understood. Our research on the epidemiology of Chagas disease in Southeastern Mexico involved sampling triatomines in rural settings. Materials and Methods: A triatomine was collected in a peridomestic environment of a rural dwelling in the state of Chiapas. The triatomine was identified morphologically as an adult female Eratyrus cuspidatus Stal. Results: Microscopic analysis revealed flagellate forms of T. cruzi in the feces of the E. cuspidatus collected. This was confirmed by quantitative polymerase chain reaction. Amplification of the mini-exon gene showed that the T. cruzi infecting E. cuspidatus corresponded to lineage I. Conclusions: This is the first report from Mexico of E. cuspidatus found infected in a human dwelling, which represents an important adaptation process to inhabit human environments.

Factors associated with tuberculosis-diabetes mellitus type 2 binomial in rural population of Oaxaca, Mexico.

INTRODUCTION: Type 2 diabetes mellitus (T2DM) is a growing condition that hinders the treatment and control of tuberculosis (TB). Several factors promote this comorbidity showing variations according to characteristics of the population affected. The objective was to identify the factors associated with the comorbidity of TB-T2DM in a rural population of Oaxaca, Mexico. METHODOLOGY: This was an unpaired case-control study. Descriptive statistics was performed for clinical and sociodemographic variables. Logistic regression was used to calculate odds ratio (OR) to identify associated factors with TB-T2DM binomial. RESULTS: 126 controls (TB+ T2DM-) and 69 cases (TB+ T2DM+) were included. 43% were considered as indigenous population. Significant differences were found according to the groups. Treatment failure was higher in individuals with binomial (p = 0.015), as well as a higher bacillary load (two crosses) and presence of pulmonary TB (p ≤ 0.001). Association analysis showed that the risk factors of binomial were: female sex (OR = 2.47; 95% CI 1.24-4.92), age ≥ 45 years (OR = 2.90; 95% CI 1.42-5.92), body mass index ≥ 25 kg/m2 (OR = 2.69; 95% CI 1.25-5.77) and presenting > 6 symptoms (OR = 2.71; 95% CI 1.19-6.14). CONCLUSIONS: This is the first report of this comorbidity in a rural Mexican population. The results highlight the growing problem of TB-T2DM, and the need to address the issue from an integral and gender perspective. Furthermore, mandatory screening is necessary in patients with T2DM to improve early diagnosis of TB and T2DM. This would promote better management of both conditions.

First report of mixed Trypanosoma cruzi discrete typing units infection in Triatoma phyllosoma in the peri-urban environment of Oaxaca, Mexico

ABSTRACT Background: Chagas disease, a zoonosis transmitted mainly by hematophagous insects of the subfamily Triatominae, is caused by Trypanosoma cruzi, classified into six discrete typing units (DTUs: TcI-TcVI and Tcbat). Methods: Insect vectors were collected from 84 human dwellings in the municipality of Santo Domingo Tehuantepec, Oaxaca, Mexico; 4.76% were infested. DTUs were determined using conventional and nested PCR. Results: The infection rate was 43.6%. All insects were infected with TcI while one specimen showed mixed infection with TcII. Conclusions: This is the first report of T. cruzi mixed infection in Triatoma phyllosoma, its main vector in the study region.