Chagas disease (ChD) is a parasitosis caused by the protozoan Trypanosoma cruzi (Tc). It is endemic to almost all Latin American countries, including the southern United States. The acute form of ChD and its actual incidence have rarely been described in Mexico, despite the extensive presence of favorable niches for its transmission. The objective of this study was to estimate the frequency of acute ChD in febrile patients at the central Pacific coast of Mexico. For this, we surveyed patients with persistent fever (5 to 10 days) in five hospitals at the Mexican states of Jalisco, Colima, and Nayarit in 2012. Samples were taken from a total of 485 patients to detect Tc in blood using the polymerase chain reaction (PCR) test and direct microscopic examination. Of these subjects, 10 were positive for PCR and none for microscopic examination (2% in 12 months). We adjusted this rate by the total people at risk in the area and obtained an incidence of 7.4/100,000 habs./year. The positive cases showed no association with sex, rural settlement, or pet ownership, only with the contact with Triatominae insects (odds ratio = 9.22 and confidence interval: 1.93-44.06). The clinical picture of positive patients showed an association with the diagnosis of lower respiratory tract infections. Meanwhile, only one fatal case showed the typical picture of acute fatal cardiomyopathy. The pulmonary manifestations of our patients suggest possible lung pathogenicity of Tc, which merits further investigation. Our findings differ markedly from the official reports for ChD. This difference suggests an underestimation of the disease. These findings urge the Mexican health authorities to implement more vigorous actions aimed at improving medical skills in the timely diagnosis of ChD, as well as to apply efficient preventive programs.
Keywords: Colima; Mexico; Triatominae; Trypanosoma cruzi; acute Chagas disease; incidence; polymerase chain reaction.