Chagas disease, also known as trypanosomiases, is a life-threatening anthropozoonosis caused by the blood parasite Trypanosoma cruzi. It has been estimated that 8 million people are infected worlwide, and more than 65 million living in risk areas. This disease is transmitted mainly to humans and some mammals (dogs, cats, rodents, marsupials, and primates) through the feces or urine of blood-sucking triatomine Reduviidae family insects. However, human infections can also occur in non-endemic areas due to blood transfusions, congenital route, organ transplantation, international migration, laboratory accidents, and the ingestion of beverages or food contaminated by the feces urine of the Triatoma [1, 2, 3, 4].
Human infections by T. cruzi present two phases of development; phase one, it is also known as acute phase, lasting up to 3 months, presenting parasitemia, fever, Romagna's sign and headaches. On the other hand, phase two, also known as chronic phase, develops even 10 years after infection (30-35% of infected cases), the parasite produces amastigote nests in various organs and peripheral nervous system, causing cardiac, nervous and digestive disorders [5, 6].
Triatomines hide in holes and slots of poorly built houses; this is one reason why Chagas disease is endemic to rural areas of Latin America. Triatomines are active at night, and is when they feed. Transmission occurs primarily through contact with the feces or urine of triatomines infected with the parasite , causing health problems in several countries of the American continent , mainly in Mexico, Brazil, and Argentina [2, 8].
Mexico is considered a country inside the endemic zone for the Chagas disease, with an estimate of more than one million infected people. Likewise, various species of mammals stand out as carriers of the parasitosis, these include dogs, cats and domestic rodents, which makes it an essential zoonotic disease and increases the risk to human health. [9, 10]. In different states of Mexico such as San Luis Potosí, Jalisco, Querétaro, Estado de Mexico, Oaxaca, and Chiapas, higher seroprevalence has been reported to humans; however, cases of seropositivity to T. cruzi have been described in all of Mexico .
In two-thirds of the Mexican territory, around 34 species of triatomines transmitting Chagas disease have been described, and these belong to the genera Rhodnius, Paratriatoma, Eratyrus, Dipetalogaster, Belminus, Panstrongylus, Meccus, and Triatoma; of which the most reported species belong to the genus Meccus and Triatoma [10, 11, 12, 13].
Concerning the genus Meccus, the most important species as transmitters are M. bassolsae, M. longipennis, M. mazzottii, M. pallidipennis, M. phyllosomus, and M. picturata [11, 13]. Within these vectors, the Phyllosoma complex comprises six species of the genus Meccus; M. longipennis, M. mazzottii, M. pallidipennis, M. picturatus, M. bassolsae, and M. phyllosomus . On the other hand, of the genus Triatoma, the most relevant species as transmitters of the parasite are T. gerstaeckeri, T. mexicana, T. rubida, T. barberi, and T. dimidiata [10, 11].
For the year 2019, the Mexican government reports that the species that transmit Chagas disease in Aguascalientes and Zacatecas are Meccus longipennis and Meccus phyllosoma (Supplementary figure 1) . In previous years, the triatomine species Triatoma (Meccus) phyllosoma and Triatoma (Meccus) longipennis have been reported in the state of Aguascalientes and Zacatecas [11, 16, 17, 18]. The synonymy for the genera is explained in 2010, when Licón-Trillo et al.  reported the presence of Meccus phyllosomus longipennis = Triatoma longipennis in Mexican territory, and Rodríguez-Bataz et al., in 2011  reported the same species as a carrier of T. cruzi in San Tadeo, Presa de Los Serna, Malpaso, Jatiche de Arriba and La Labor towns, in Aguascalientes,
Mexico. In the same year, Meccus longipennis was reported as a species distributed in Aguascalientes and Zacatecas [11, 21]. For the case of Triatoma phyllosoma, Cortés-Jiménez et al. in 1996 , reported his findings for Aguascaliente’s’ state and in 2006 Cruz-Reyes and Pickering-Lopez  reported presence of T. longipennis and T. phyllosoma in the states of Aguascalientes and Zacatecas.
This work's objective was to determine the distribution of Triatoma (Meccus) phyllosoma and Triatoma (Meccus) longipennis in various localities of Aguascalientes and Zacatecas and to establish the relevance of these triatomines as vectors of Chagas disease.