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Title: DIFFERENTIAL IDENTIFICATION OF ASCOGREGARINA SPECIES (APICOMPLEXA: LECUDINIDAE) IN AEDES AEGYPTI AND AEDES ALBOPICTUS (DIPTERA: CULICIDAE) BY THE POLYMERASE CHAIN REACTION

Author
item MORALES, M - TULANE UNIV, NEW ORLEANS
item OCAMPO, C - TULANE UNIV, NEW ORLEANS
item CADENA, H - CIDEIM, COLOMBIA
item Copeland, Claudia
item TERMINI, M - TULANE UNIV, NEW ORLEANS
item WESSON, D - TULANE UNIV, NEW ORLEANS

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2005
Publication Date: 7/1/2005
Citation: Morales, M.E., Ocampo, C., Cadena, H., Copeland, C.S., Termini, M., Wesson, D. 2005. Differential identification of Ascogregarina species (Apicomplexa: Lecudinidae) in Aedes aegypti and Aedes albopictus (Diptera: Culicidae) by the polymerase chain reaction. Journal of Parasitology. 91:1352-1356.

Interpretive Summary: Ascogregarina is a protozoan parasite of mosquitoes that may be of potential use as a biological control agent. Different species of Ascogregarina have different effects on different mosquito hosts, so it is important to distinguish which species is infecting the mosquito in question. Ascogregarina culicis and Ascogregarina taiwanensis are morphologically indistinguishable except possibly when examined by an expert under phase-contrast microscopy, a labor intensive method that is prohibitively expensive. While at Tulane University a scientist now at the Center for medical, Agricultural and Veterinary Entomology (Gainesville, FL) developed two methods for cost-effective and time-effective Ascogregarina identification. The first is a test for the presence of Ascogregarina of any of the three species in question. Using this method, mosquito specimens can be screened for infection with Ascogregarina using a simple and time-effective assay. The second is a species-specific test that distinguishes between Ascogregarina culicis and Ascogregarina taiwanensis, the two species that are not reliably distinguished by morphology. These techniques should accelerate investigations into mosquito biological control.

Technical Abstract: We report two polymerase chain reaction (PCR)-based methods for distinguishing morphologically similar gregarine species based on amplification of variable regions of the internal transcribed spacer gene of ribosomal DNA. The gregarines we investigated were Ascogregarina barretti (Vavra), A. culicis (Ross), and A. taiwanensis (Lien & Levine), parasites of the mosquitoes Ochlerotatus triseriatus (Say), Aedes aegypti (Lynn.), and A. albopictus (Skuse), respectively. These three important vector mosquitoes often utilize the same container habitats, where larval development and infection by the parasite occurs, leaving ample opportunity for cross-species gregarine infection. Since previous studies have shown that the parasites A. culicis and A. taiwanensis variably affect fitness in both normal and abnormal mosquito hosts, distinguishing parasite infection and species is important. The task is complicated by the fact that these two parasite species are virtually identical in morphology, while A. barretti is morphologically distinct. The first PCR-based detection assay provides a rapid, sensitive and straightforward means of detection of Ascogregarina sp. in any mosquito species based on a single PCR amplification. The second method provides a means of differentiation between A. culicis and A. taiwanensis based on a species-specific PCR assay. Together, these assays allow whole mosquitoes to be tested for the presence of Ascogregarina species, and identification of both A. culicis and A. taiwanensis singly or in dual infection.