We used 5 diagnostic lab tests inside a cross-sectional investigation of the prevalence of in Tejupilco municipality, State of Mexico, Mexico. triatomines with humans and reservoir animal hosts (have the highest vectorial activity in central and southern Mexico (in the southern part of the State of Mexico (infestation index 9.9%, density index 2.7%C3.0%) and suggested that active transmission of may occur (illness of triatomines and transmission within human being dwellings (in dogs and the role of these reservoir animals in parasite transmission in the State of Mexico have not been determined. In this study, we statement the seroprevalence of among individuals and dogs in the villages in the southern part of the State of Mexico and discuss the potential diagnostic meaning of seropositivity in dogs for identifying seroprevalence in humans. We also present data suggesting the likelihood of transmission in Toluca. Our observations emphasize that relevant health agencies need to U-10858 conduct active epidemiologic surveillance programs and implement vector control strategies in the State of Mexico. Materials and Methods Parasites epimastigotes were cultivated as previously described (transmission, most test samples (>94%) were from children (age range 2C15 years) with a sex distribution consistent with the regional and national census. Sample randomization was controlled by using EpiInfo version 3.3.2 (Centers for Disease Control and Prevention, Atlanta, GA, USA). Oral informed consent was obtained from adults and parents of minors enrolled in the study. Trained ISEM personnel performed venipuncture to obtain blood samples. The study was reviewed and approved by the human subjects committees at ISEM and UTMB. Dog serum samples were collected in Toluca and the villages selected for human screening. Toluca, the capital of the State of Mexico (altitude 2,680 m, average temperature 15C, range 5CC24C) is considered free of vectorial transmission because triatomines (with or without by enzyme-linked immunosorbent assay (ELISA) as previously described (by ELISA, an indirect hemagglutination (IHA) test, and an indirect immunofluorescence (IIF) assay. For the ELISA, 96-well, flat-bottomed plates U-10858 were UV irradiated, incubated for 1 h at 37C with epimastigote antigen extract, and blocked with 50 L Tris-buffered saline, 0.1% Tween 20, and 5% nonfat dry milk. Plates were incubated at 37C with 50 L of each test serum sample (1:50 dilution) for 2 h, horseradish peroxidaseCconjugated IgG (1:50 dilution) for 1 h, and substrate (o-phenylenediamine) for 20 min. The reaction was stopped by adding 2 N H2SO4, and the optical density (OD) was read at 490 nm (in this study because it has shown limited sensitivity (test and validated with the Fisher exact test. The level of agreement for serologic data from 5 tests conducted at UTMB and InDRE was assessed as previously described (by immunofluorescence flow cytometry. Fluorescein isothiocyanate fluorescence intensities for in persons in southern area of the State of Mexico*? Table 2 Prevalence of antibodies to in persons MRC1 in southern area of the State of Mexico* Our data showed that 16 (5.5%) of 293 persons in Tejupilco were seropositive for IgM antibodies to (Table 2). The prevalence of IgM U-10858 antibodies was higher in female than in male patients (64% vs. 36%). All serum samples positive by ELISA for IgM antibodies were also positive by IFC (50%C93% of the parasites with an LFI of 102C103) (Figure 3). The overall prevalence of infection and transmission were reportedly endemic ((IgG 15.8%, IgM 11.4%, IgG and IgM 21.0%) (Table 3). A total of 6.1% of the dogs from Tejupilco were positive for both IgG and IgM (Figure 4C), and no sex-related differences in prevalence of U-10858 parasite-specific antibodies were observed. IgG seropositivity increased with age, with the highest seroprevalence in dogs 3C6 years of age. All samples seropositive by ELISA were seropositive by IFC. A total of 57% to 94% of the parasites showed IgG-specific staining (LFI 102C104), and 86%C98% showed IgM-specific staining (LFI 100 to 4 103) (Figure 3). Samples seropositive for IgG were confirmed by IHA (data not shown). None of the serum samples from dogs in northern villages (Apaxco, Hueypoxtla, Jaltenco, and Nextlalpan) within the Condition of Mexico or.