Colombian Anopheles triannulatus (Diptera: Culicidae) Naturally Infected with Plasmodium spp.

The role of Anopheles triannulatus as a local vector has not yet been defined for malaria-endemic regions of Colombia. Therefore, the aim of this work was to detect An. triannulatus naturally infected with Plasmodium spp., as an approximation to determining its importance as malaria vector in the country. A total of 510 An. triannulatus were collected in six malaria-endemic localities of NW and SE Colombia from January 2009 to March 2011. In the NW, two specimens were naturally infected; one with Plasmodium vivax VK247, collected biting on humans and the other with Plasmodium falciparum, collected resting on cattle. In the SE, two specimens were positive for P. falciparum. Although these results show An. triannulatus naturally infected with Plasmodium, further studies are recommended to demonstrate the epidemiological importance of this species in malaria-endemic regions of Colombia. 1. Introduction Malaria is an important public health problem in Colombia with approximately 60% of the territory being suitable for disease transmission [1]. In 2010, 116,914 malaria cases were reported [2], for an annual parasite index (API) of 11.58/1,000 inhabitants, and in 2011, only 62,969 cases were reported for API of 6.2/1,000 inhabitants [3], although underregistration of cases is presumed [4]. The Urabá-Bajo Cauca and Alto Sinú (UCS) epidemiological region, NW Colombia, registers near 60% of the total malaria cases of the country and the Amazonas region, SE, 0.67% [2, 5]. In Colombia, based on epidemiological, entomological or parasite detection records, at least nine Anopheles species have been incriminated as malaria vectors. Three are of primary importance: Anopheles (Nyssorhynchus) albimanus Wiedemann 1920, Anopheles (Nys.) darlingi Root 1926, and Anopheles (Nys.) nuneztovari Gabaldón 1940, and six other species have relevance as secondary or local vectors [6–9]. However, there are species that in neighboring countries have been incriminated as local or regional vectors, but their role in transmission is not yet established for Colombia [1]. This is the case of Anopheles (Nys.) triannulatus Neiva and Pinto 1922, a species widely distributed in the country [10]. Interestingly, in Cimitarra municipality, NE Colombia, it was the most abundant species collected and had an indoor biting behavior similar to the main vector, An. nuneztovari [11]. Also, in Santa Rosa de Lima, Bolivar, in northern Colombia, An. triannulatus was the predominant species, found in sympatry with the primary malaria vector An. albimanus [9]. Furthermore, in localities of the Amazon Region,