RESUMEN
Paragonimiasis is a subacute to chronic inflammatory granulomatous lung disease caused by the genus Paragonimus. In Latin America Paragonimus mexicanus Miyazaki & Ishii, 1968 is the only confirmed species to cause human infections. Paragonimus caliensis Little, 1968 is an uncommon species often regarded as a synonym of P. mexicanus. Recently, the study of two types of Paragonimus metacercariae from Costa Rica has provided new molecular and morphological evidence that P. caliensis is a separate species from P. mexicanus. In the present study, molecular, morphological and phylogenetic tools have been used to characterize two populations of Paragonimus located at west of Medellin, Antioquia and at Pichinde, Valle del Cauca (type locality of P. caliensis), Colombia. Adults and metacercariae obtained from Medellin, and metacercariae from Pichinde were analyzed. For morphological observations we used light microscopy and scanning electron microscopy (SEM). Morphology of metacercariae and adults matched with the holotype of P. caliensis. The number and arrangement of sensory papillae in the acetabulum region differs from the morphotypes reported for P. caliensis in Costa Rica. Two morphotypes in branching patterns of ovary and two morphotypes in branching patterns of testes were identified. The main morphological differences between P. caliensis and P. mexicanus corresponded to the size of gonads and their relative positions in the body, and the occasional presence of a cyst wall in P. caliensis metacercariae. The molecular and phylogenetic analyses (using nuclear ribosomal ITS2 and partial cytochrome c oxidase subunit 1 CO1 sequences) confirmed that P. caliensis from the type locality is the same species from Medellin and Costa Rica. Furthermore, these analyses also suggest genetic as well as geographical separation of P. caliensis populations between Colombia and Costa Rica. Currently, P. mexicanus and P. caliensis are sympatric in the Colombian Pacific bioregion, and specific diagnosis based on their egg size is not possible. Therefore, it is necessary to determine the biogeographic distribution ranges of both species and to implement molecular techniques to establish the role of P. caliensis in human paragonimiasis in Colombia.
Asunto(s)
Braquiuros/parasitología , Enfermedades Pulmonares Parasitarias/parasitología , Metacercarias/genética , Paragonimiasis/parasitología , Paragonimus/fisiología , Animales , Colombia , ADN de Helmintos/genética , ADN Espaciador Ribosómico/genética , Humanos , Microscopía Electrónica de Rastreo , Paragonimiasis/patología , Paragonimus/anatomía & histología , Filogenia , Análisis de Secuencia de ADNRESUMEN
Although no natural infections with lung flukes were encountered in the hydrobioid snail Aroapyrgus colombiensis from streams in the Condebamba Valley, Peru, laboratory-bred snails were readily susceptible to infection with miracidia of Paragonimus peruvianus. The redia and cercaria are described for the first time for those of neotropical lung flukes. Cercariae inside rediae did not have a stylet and development was apparently completed outside the rediae in snail tissues. The microcercous xiphidiocercaria had 2 groups of gland cells on each side; the outer consisted of 5 cells and the inner of 3 cells, all with ducts opening at the stylet. The excretory bladder was large, often triangular, was thick-walled, and of 1 layer of cuboidal cells. The redia lacked procrusculi and had a short intestine which was slightly longer than the pharynx.