Clinical and epidemiological characteristics of diarrhea associated with Vibrio mimicus were identified in 33 hospitalized patients referred to the Costa Rican National Diagnostic Laboratory Network between 1991 and 1994. The relevant symptoms presented by patients included abundant watery diarrhea, vomiting, and severe dehydration that required intravenous Dhaka solution in 83% of patients but not fever. Seroconversion against V. mimicus was demonstrated in four patients, from whom acute-and convalescent-phase sera were obtained. Those sera did not show cross-reaction when tested against Vibrio cholerae O1 strain VC-12. All the V. mimicus isolates from these cases produced cholera toxin (CT) and were susceptible to commonly used antibiotics. Attempts to isolate this bacterium from stool samples of 127 healthy persons were not successful. Consumption of raw turtle eggs was recalled by 11 of the 19 (58%) individuals interviewed. All but two V. mimicus diarrheal cases were sporadic. These two had a history of a common source of turtle (Lepidochelys olivacea) eggs for consumption, and V. mimicus was isolated from eggs from the same source (a local market). Among the strains, variations in the antimicrobial susceptibility pattern were observed. None of the strains recovered from market turtle eggs nor the four isolates from river water showed CT production. Further efforts to demonstrate the presence of CT-producing V. mimicus strains in turtle eggs were made. Successful results were obtained when nest eggs were tested. In this case, it was possible to isolate CT-and non-CT-producing strains, even from the same egg. For CT detection we used PCR, enzyme-linked immunosorbent assay (ELISA), and Y-1 cell assay, obtaining a 100% correlation between ELISA and PCR results. Primers Col-1 and Col-2, originally described as specific for the V. cholerae O1 ctxA gene, also amplified a 302-bp segment with an identical restriction map from V. mimicus. These results have important implications for epidemiological surveillance in tropical countries where turtle eggs are used for human consumption, serving as potential sources of cholera-like diarrhea.

Vibrio mimicus contamination of sand increased significantly during the arrival of the olive ridley sea turtles (Lepidochelys olivacea) at Ostional anidation beach, Costa Rica. Statistical analysis supports that eggs are contaminated withV. mimicus by contact with the sand nest. V. mimicus was isolated from eggs of all nests tested, andctxA + strains were found in 31% of the nests, all of which were near the estuary.

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Se presentan cuatro nuevos registros de dinoflagelados y el reporte de dos dinoflagelados desnudos planctónicos para la Bahía de La Paz y el Golfo de California. Los Brachidiniales Asterodinium gracile y Brachidinium sp. son nuevos registros para el Pacífico Mexicano y Brachidinium capitatum es nuevo registro para el Golfo de California. Se conoce poco acerca de la distribución y morfología de estas especies ya que son raras y se han reportado en pocas ocasiones. A. gracile y Kofoidinium pavillardii son consideradas especies de la flora de sombra. En este trabajo se documentaron fotográficamente todas las especies. New records of naked dinoflagellates from the Gulf of California, Mexico Four new records of naked planktonic dinoflagellate and two rare taxa were found in Bahía de La Paz, Gulf of California. The Brachidiniales Asterodinium gracile and Brachidinium sp. are new records for the Mexican Pacific and Brachidinium capitatum is a new record for the Gulf of California. Little is known about the distribution and morphology of these species since they are rare and have been scarcely reported in the worldwide literature. A. gracile and Kofoidinium pavillardii are considered as members of the shade flora. All species are photographically documented.

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