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Rivas, Nicaragua

Gonzalez-Ceron L.,Instituto Nacional Of Salud Publica | Martinez-Barnetche J.,Instituto Nacional Of Salud Publica | Montero-Solis C.,Instituto Nacional Of Salud Publica | Santillan F.,Instituto Nacional Of Salud Publica | And 4 more authors.
Malaria Journal | Year: 2013

Background: The origins and dispersal of Plasmodium vivax to its current worldwide distribution remains controversial. Although progress on P. vivax genetics and genomics has been achieved worldwide, information concerning New World parasites remains fragmented and largely incomplete. More information on the genetic diversity in Latin America (LA) is needed to better explain current patterns of parasite dispersion and evolution. Methods. Plasmodium vivax circumsporozoite protein gene polymorphism was investigated using polymerase chain reaction amplification and restriction fragment length polymorphism (PCR-RFLP), and Sanger sequencing in isolates from the Pacific Ocean coast of Mexico, Nicaragua, and Peru. In conjunction with worldwide sequences retrieved from the Genbank, mismatch distribution analysis of central repeat region (CRR), frequency estimation of unique repeat types and phylogenetic analysis of the 3′ terminal region, were performed to obtain an integrative view of the genetic relationships between regional and worldwide isolates. Results: Four RFLP subtypes, vk210a, b, c and d were identified in Southern Mexico and three subtypes vk210a, e and f in Nicaragua. The nucleotide sequences showed that Mexican vk210a and all Nicaraguan isolates were similar to other American parasites. In contrast, vk210b, c and d were less frequent, had a domain ANKKAEDA in their carboxyl end and clustered with Asian isolates. All vk247 isolates from Mexico and Peru had identical RFLP pattern. Their nucleotide sequences showed two copies of GGQAAGGNAANKKAGDAGA at the carboxyl end. Differences in mismatch distribution parameters of the CRR separate vk247 from most vk210 isolates. While vk247 isolates display a homogeneous pattern with no geographical clustering, vk210 isolates display a heterogeneous geographically clustered pattern which clearly separates LA from non-American isolates, except vk210b, c and d from Southern Mexico. Conclusions: The presence of vk210a in Mexico and vk210e, f and g in Nicaragua are consistent with other previously reported LA isolates and reflect their circulation throughout the continent. The vk210b, c and d are novel genotypes in LA. Their genetic relationships and low variability within these vk210 and/or within the vk247 parasites in Southern Mexico suggest its recent introduction and/or recent expansion to this region. The global analysis of P. vivax csp suggests this parasite introduction to the region and likely LA by different independent events. © 2013 González-Cerón et al.; licensee BioMed Central Ltd.


Walton W.E.,University of California at Riverside | Popko D.A.,University of California at Riverside | Van Dam A.R.,University of California at Riverside | Merrill A.,Vector Control Program
Journal of the American Mosquito Control Association | Year: 2013

The distribution and abundance of emerging Culex spp. were assessed within narrow (width: 3 m) and wide (width: 20 m) bands of California bulrush (Schoenoplectus californicus) and in the open water adjacent to emergent vegetation in 2 marshes of an ammonia-dominated wastewater treatment wetland in southern California. Emerging mosquitoes were collected along transects perpendicular to the path of water flow at 3 distances (1.5, 5, and 10 m) from the vegetation-open water interface in the wide bands of emergent vegetation, at the center of narrow bands of emergent vegetation, and at 1.5 m from the edge of emergent vegetation in the open water. The width of vegetation bands (3 vs. 20 m) influenced the effectiveness of integrated mosquito management practices, especially the application of mosquito control agents. Mosquito production from the 2 marshes also differed up to 14-fold, suggesting that the distance between the shorelines (62 vs. 74 m) of each marsh also influenced the efficacy of mosquito control agents applied from the shore and boats. Hot spots of mosquito production (75-424 female Culex/m2/day) were found within the wide bands of bulrush. During summer, the relative abundance of Culex stigmatosoma among emerging mosquitoes increased from the periphery to the center of wide bands of emergent vegetation. Culex erythrothorax emergence rates were comparatively similar among the transects in the wide bands of emergent vegetation. Culex tarsalis adults increased in number from the periphery to the center of wide bands of bulrush and, in May, were >95% of emerged mosquitoes. Copyright © 2013 by The American Mosquito Control Association, Inc.


Walton W.E.,University of California at Riverside | Popko D.A.,University of California at Riverside | Van Dam A.R.,University of California at Riverside | Van Dam A.R.,University of California at Davis | And 3 more authors.
Ecological Engineering | Year: 2012

The abundance and distribution of Culex spp. mosquitoes, mosquito-eating fish (Gambusia affinis), and other macroinvertebrates were assessed within wide (width: 20m) and narrow (width: 3m) bands of California bulrush (Schoenoplectus californicus) and in the open water adjacent to emergent vegetation in two marshes of an ammonia-dominated wastewater treatment wetland in southern California. Emergence traps and minnow traps were used to collect fauna along transects perpendicular to the path of water flow at three distances (1.5, 5 and 10m) from the vegetation-open water interface in the wide bands of emergent vegetation, at the center of narrow bands of emergent vegetation and at 1.5m from the edge of emergent vegetation in the open water. Mosquito production was least from the open water sites and, relative to sites within the wide band of vegetation in each of the two marshes studied, was significantly lower from the narrow bands of emergent vegetation where mosquitofish populations increased comparatively more during the summer and nektonic predatory insects (Notonectidae) were more abundant. Adult mosquito production was greatest at the middle of wide bands of bulrush. Despite an ongoing integrated mosquito management (IMM) program that included routine application of larvicides and adulticides, Culex mosquitoes emerged in large numbers (>200 individuals/m 2/day) along transects within the interiors of wide bands of emergent vegetation in the late spring and summer. The width of bands of emergent vegetation in constructed treatment wetlands should be minimized to the greatest extent possible to achieve water quality goals yet to facilitate both ecological and, when necessary, chemical control of mosquitoes. © 2012 Elsevier B.V.

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