Occurence of Thelazia lacrymalis - (Nematoda, Spirurida, Thelaziidae) in horses in Germany

Adspection of the eyes and investigation of samples after lavage of the nas olacrimal duct and/or the conjunctival sac with saline revealed that 18 (11 ,5%) of the 156 horses examined Mm-e infected with Thelazia lacrymalis. The infected horses originated from Bavaria, Baden-Wurttemberg, Hesse, Saxony or Brandenburg. In narcotized horses, infections were demonstrated in five (22,7%) of 22 animals examining both eyes, but in ten (10,7%) of 93 horses, if only one eye could be investigated. In non-narcotized horses standing u pright and examined exclusively by lavage of the nasolacrimal duct and/or t he conjunctival sac, three (7,3%) of 41 animals could be proved to be infec ted, however, only larvae I were isolated. Considering the 18 positive hors es, infections were recognized by detection only of adult worms in twelve, exclusively by isolation of larvae in three and by finding both stages, lar vae I and adult worms, in three animals. Clinical signs at the infected eye s such as corneal nicer, corneal opacity, keratitis, conjunctivitis or recu rrent uveitis were noted in 13 of the 18 positive horses.