Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/5/2007
Publication Date: 10/4/2007
Citation: Miciele, M.V., Marti, G.A., Tranchida, M.C., Becnel, J.J. 2007. Epizootiological studies of Amblyospora camposi (Microsporidia: Amblyosporidae) in Culex renatoi (Diptera: Culicidae) and Paracyclops fimbriatus fimbriatus (Copepoda: Cyclopidae) in a bromeliad habitat. Journal of Invertebrate Pathology. 94(1):31-37. Interpretive Summary: Naturally occurring protozoan parasites (Microsporidia) of mosquitoes are under study by USDA/ARS scientists to evaluate and develop these disease causing organisms as biological control agents. Microsporidian parasites are known to cause mortality in mosquitoes worldwide and recent advances on fundamental aspects of their life cycles and modes of transmission has led to renewed interest in these pathogens as microbial control agents. This study ahs examined the epizootiology of a mosquito pathogen in field populations of its primary mosquito host and its intermediate host over a 2-year period tounderstand the transmission and survival strategies used by this microsporidium in this specialized habitat. New information obtained here contributes to our basic understanding of these parasites which we hope will assist in the evaluation and development of microsporidia as biocontrol agents.
Technical Abstract: The epizootiology of Amblyospora camposi was studied in a natural population of Culex renatoi, a bromeliad-inhabiting mosquito, and its intermediate host, Paracyclops fimbriatus fimbriatus, over a 2-year period. Twenty Eryngium cabrerae plants were sampled monthly from January 2003 to January 2005 and the prevalence of A. camposi in P. f. fimbriatus and Cx. renatoi populations was determined. The monthly prevalence rates of meiospore infections in Cx. renatoi larvae never exceeded 5,5% and was detected in 50% of the monthly samples. Meiospores were available in plants over the course of the study at a mean concentration of 2 x 10 4 meiospores/ml. Within each plant the parasite was maintained by horizontal transmission. P. f. fimbriatus with vegetative stages and mature spores were found regularly in bromeliads suggesting efficient meiospore infectivity to field copepod populations. The mean concentration of spores from copepods found in plants was 8 x 10 2 spores/ml. Infections in copepods were detected in 54% of the monthly samples with a prevalence rate ranging from 0,55 to 17,4% and an overall average of 5,1%. Vegetative stages in fourth instar mosquito larvae (probably derived from the horizontal pathway via spores formed in copepods) were detected in 12.5% of the monthly samples with an overall prevalence rate of 1,1%. Infections in female and male adults were detected in 20,8% of the monthly samples with an overall average of 4,1% and 6,8% respectively.