Entomological Survey and Leishmania (Leishmania) mexicana Prevalence in Sand Fly Species during an Outbreak of Cutaneous Leishmaniasis in Quintana Roo State, Mexico.

(1) Background: Localized cutaneous leishmaniasis is a neglected vector-borne disease that has become a serious public health problem in the Yucatan Peninsula. Although more than 60% of cases originate from the state of Quintana Roo, it is one of the least explored areas in terms of incriminating vectors of the Leishmania parasite. Additionally, cases of leishmaniasis have increased substantially in that region in recent years. For this reason, we explored and provided primary evidence of Leishmania DNA in sand fly species from four localities during outbreaks of leishmaniasis in Quintana Roo. We also contributed information on the regional genetic diversity of Leishmania parasites. (2) Methods: Sand flies were collected during several periods from November 2022 to April 2023 using Mosquito Light Circle and Shannon traps, as well as an active entomological search in refuges. For Leishmania detection, we amplified a fragment of 300-350 bp of the internal transcribed spacer subunit 1 (ITS-1). (3) Results: Of the 242 females collected, we detected Leishmania DNA in 25 specimens represented by Bichromomyia olmeca (1), Psathyromyia shannoni (17), Lutzomyia cruciata (4), Psathyromyia undulata (2), and Dampfomyia deleoni (1). The detection of Leishmania in these last two species represents new records for the Yucatan Peninsula and for Mexico. Leishmania (Leishmania) mexicana was the only species detected in the Phlebotominae species, with prevalence values that ranked between 7.41% and 33.33% from specimens collected in the sylvatic areas of Cozumel Island and Petcacab. (4) Conclusions: This study provides the first evidence of infection of Da. deleoni and Pa. undulata by L. (L.) Mexicana. In addition, the presence of three dominant haplotypes in all the evaluated localities was evidenced using the analysis of genetic diversity, and the locality of Petcacab was the one with the circulation of two new haplotypes not previously described in Mexico or neighboring countries. These results highlight the importance of intensive epidemiological surveillance due to the dynamics of transmission of Leishmania between different species.

First detection of Leishmania DNA in Lutzomyia longipalpis sensu lato (Diptera: Phlebotominae) in southem Mexico.

Background & objectives: Lutzomyia longipalpis sensu lato is an important vector of Leishmania infantum, the causative agent of visceral leishmaniasis (VL) in Latin America. In Mexico, this species has been recorded in endemic areas of leishmaniasis transmission, but it has never been detected as infected with Leishmania sp. This study aimed to explore the presence of Leishmania DNA in Lutzomyia longipalpis s.l. from samples collected with a human baited trap from an endemic region of leishmaniasis in southeastern Mexico. Methods: This is a prospective study where a total of 45 specimens of Lu. longipalpis s.l. collected in two sites of Yucatan state with records of leishmaniasis were tested. The nuclear ribosomal Internal Transcribed Spacer was amplified for the detection of Leishmania DNA. Results: Two females were positive for Leishmania DNA. None of the specimens positive for parasite DNA were found fed or gravid. Our finding represents the first record of infection by Leishmania in Lu. longipalpis s.l. for the country. Interpretation & conclusion: More studies are necessary to understand the potential role of this vector species in the transmission cycle of the causative agent of leishmaniasis in the southeastern and other regions of Mexico.

Inferring the Potential Distribution of an Emerging Rickettsiosis in America: The Case of Rickettsia parkeri.

Tick-borne rickettsioses represent a severe public health problem that has increased in recent decades by several activities that place human populations in contact with a wide range of vectors. In particular, Rickettsia parkeri, an eschar-associated spotted fever agent, represents an emerging pathogen that has been gradually identified throughout America. In the present work, we compiled an occurrence database of these bacteria, as well as its vectors, in order to identify the potential distribution of these bacteria and to detect the risk areas where this emerging pathogen may be circulating. The results show the at-risk areas to be broad regions in Central America, on the coast of Venezuela, Colombia, Ecuador, Peru, and Chile, part of Brazil and Argentina, and the greater part of Bolivia, Paraguay, and Uruguay. Particularly, in Mexico, conditions exist for widespread dissemination. Our results must be considered for the establishment of active acarological surveillance in previously unsampled areas, as well as the establishment of prevention measures for vulnerable populations and risk groups participating in outdoor activities that can place them in contact with this pathogen.