Laboratory Evaluation and Field Feasibility of Micro-Encapsulated Insecticide Effect on Rhodnius prolixus and Triatoma dimidiata Mortality in Rural Households in Boyacá, Colombia.

Chagas disease is a neglected vector-borne zoonosis caused by the parasite Trypanosoma cruzi that is primarily transmitted by insects of the subfamily Triatominae. Although control efforts targeting domestic infestations of Rhodnius prolixus have been largely successful, with several regions in Boyacá department certified free of T. cruzi transmission by intradomicile R. prolixus, novel native species are emerging, increasing the risk of disease. Triatoma dimidiata is the second most important species in Colombia, and conventional control methods seem to be less effective. In this study we evaluated the efficacy and usefulness of micro-encapsulated insecticide paints in laboratory conditions and its applicability in rural communities to avoid triatomine domiciliation. Laboratory conditions measured mortality at 6 months and 12 months, with an average mortality between 93-100% for T. dimidiata and 100% for R. prolixus. Evaluation of triatomine infestation in rural households was measured after one year, with an overall perception of effectiveness in reducing household domiciliation. Although triatomines were still spotted inside and around the homes, our findings demonstrate the ability of micro-encapsulated insecticide to prevent colonization inside the households when comparing infestation rates from previous years. Current control measures suggest insecticide spraying every six months, which implies great economic cost and logistical effort. Complementary triatomine control measures with insecticide spraying and micro-encapsulated insecticide paint would make public health efforts more efficient and reduce the frequency of treatment.

New carrion-visiting flesh flies (Diptera: Sarcophagidae) from tropical dry forests of Colombia and their phylogenetic affinities.

Many flesh flies of the subfamily Sarcophaginae are very competitive carrion visitors and breeders, and several are synanthropic species of medical and forensic importance. The knowledge of these taxa is still limited, which is more noticeable in sub-sampled ecosystems such as the tropical dry forests of Colombia. Four new species, Blaesoxipha (Gigantotheca) wajiira sp. nov., Lepidodexia deborarangoa sp. nov., Oxysarcodexia luriza sp. nov. and Udamopyga iku sp. nov., are described from tropical dry forests in the Colombian departments of Atlántico, Bolívar, Cesar and La Guajira, all collected using Van Someren-Rydon traps baited separately with fermented fruit, decomposing fish and human feces. The species B. (G.) wajiira sp. nov. is probably synanthropic, while the remaining three new species avoid habitats in and around built-up areas. A phylogenetic parsimony analysis based on 222 morphological characters across 121 taxa of flesh flies recovers each new species nested within their respective genus. The subgeneric affiliation of L. deborarangoa sp. nov. within the large and diverse genus Lepidodexia (sensu lato) is inconclusive, and potential issues of relying solely on external morphological characters for generic and subgeneric classifications are highlighted. The species Lepidodexia (Notochaeta) woodi (Lopes), Oxyvinia wicharti (Lopes) and Sarcofahrtiopsis spinetta Mulieri & Dufek are new records for Colombia. COI sequence data are provided for U. iku sp. nov., L. (N.) woodi and O. wicharti.

DNA barcoding for identifying synanthropic flesh flies (Diptera, Sarcophagidae) of Colombia.

The first step for a successful use of any insect as indicator in forensic sciences is providing a precise taxonomic identification at species level. Due to morphology-based identification of Sarcophaginae flies (Diptera, Sarcophagidae) is often difficult and requires strong taxonomic expertise, their use as forensic indicators has been limited. Consequently, molecular-based approaches have been accepted as alternative means of identification. Thus, we aimed testing the efficiency of the barcode region of the mitochondrial cytochrome oxidase subunit I (COI) gene for identification of synanthropic flesh flies of several species of the genera Peckia, Oxysarcodexia, Ravinia, and Tricharaea collected in Colombia. The 645-bp fragment of COI was amplified and aligned (215 parsimoniously informative variable sites). We calculated Kimura two-parameter genetic distances and reconstruct a Neighbor-Joining phylogenetic tree. Our Neighbor-Joining tree recovered all species as monophyletic, and confirmed a new species of the genus Ravinia as also indicated by the interspecific genetic divergences and morphological observations. We obtained a 100% of identification success. Thus, the COI barcodes showed efficiency as an alternative mean of identification of species of flesh flies collected on decaying organic matter in Colombia.