Entomological evaluation by pool screen polymerase chain reaction of Onchocerca volvulus transmission in Ecuador following mass Mectizan distribution.

The prevalence of infected and infective black flies was estimated by pool screen polymerase chain reaction (PCR) amplification in the three river basins in Ecuador endemic for onchocerciasis. Mass distribution of ivermectin (Mectizan) resulted in dramatic declines in the prevalence of infected and infective flies. In the Rio Santiago river basin, no infections were detected, suggesting that transmission had ceased. The ratio of infected to infective flies in Simulium exiguum was 10-fold lower than the corresponding ratio for Simulium quadrivittatum, suggesting that S. exiguum is a more-competent vector for Onchocerca volvulus than S. quadrivittatum. However, the prevalence of infective flies in the two species was not different, suggesting that S. quadrivittatum may play an important vectorial role where it is the dominant human-biting species. The data demonstrate that pool screen PCR is an efficient way to monitor transmission in areas subject to control, and to certify an area as free of O. volvulus transmission.

Anterior uveitis after laser in situ keratomileusis.

PURPOSE: To report a case series of anterior uveitis after laser in situ keratomileusis (LASIK) and the incidence of anterior uveitis at a mean of 3 years. SETTING: Centro Medico Docente La Trinidad and Clinica Oftalmologica Centro Caracas, Caracas, Venezuela. METHODS: Five refractive surgeons and 18488 eyes that had surgical correction of a mean ametropia of -2.23 diopters (D) (range -10.25 to +4.25 D) participated in the study; 74.3% of the eyes were myopic. Laser in situ keratomileusis was performed in all eyes. Patients were followed for a mean of 36 months (range 6 to 48 months) after LASIK. The clinical charts of patients who developed uveitis after LASIK were reviewed. The mean preoperative intraocular pressure (IOP) was 15.2 mm Hg (range 12 to 19 mm Hg). The mean corneal ablation depth was 37.47 micro m (range 12 to 98 micro m). In the immediate postoperative period, all patients received a combination of topical dexamethasone and tobramycin. RESULTS: Thirty-five eyes (18 patients) developed anterior uveitis after LASIK. Signs and symptoms appeared a mean of 20.7 days (range 17 to 28 days) postoperatively and 5.08 days (range 2 to 8 days) after withdrawal of topical steroid and antibiotic agents. Eyes that developed LASIK-related uveitis had a mean preoperative spherical equivalent of -2.32 D (range -7.00 to +4.25 D). Intraocular pressure dropped to a mean of 8.0 mm Hg (range 4 to 12 mm Hg) at the onset of uveitis (P <.0001). The LASIK-related anterior uveitis resolved and IOP returned to baseline after a mean of 3 days on topical steroid and cycloplegic agents. Laboratory and immunology (including human leukocyte antigen-B27) tests were negative in 15 of 18 patients (83.33%). The incidence of uveitis after LASIK was 0.18%. CONCLUSIONS: Anterior uveitis after LASIK is infrequent. It may be due to uveal trauma during surgery with disruption of normal anterior-chamber-associated immune deviation, decreased antiinflammatory cytokines, and increased proinflammatory cytokines. Further studies are needed to investigate the mechanisms of this association.