Oocysts of Cryptosporidium from snakes are not infectious to ducklings but retain viability after intestinal passage through a refractory host

• Published in: Veterinary parasitology Vol. 77; no. 1; pp. 33 - 40
• Main Authors: Graczyk, T.K., Cranfield, M.R., Fayer, R.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.1998
• Subjects: Animals; Bird Diseases - parasitology; Bird Diseases - transmission; CANARD; Cryptosporidiosis - parasitology; Cryptosporidiosis - transmission; CRYPTOSPORIDIUM; Cryptosporidium - growth & development; Cryptosporidium - pathogenicity; Cryptosporidium serpentis; Cryptosporidiumserpentis; CULEBRA; DUCKS; Ducks - parasitology; Feces - parasitology; INFECCIONES POR PROTOZOOS; PATO; PROTOZOAL INFECTIONS; PROTOZOOSE; SERPENT; Serpentes; Snake; SNAKES; Snakes - parasitology; Transmission; Snake; Cryptosporidium serpentis; Transmission
• ISSN: 0304-4017; 1873-2550
• DOI: 10.1016/S0304-4017(97)00137-4

Six 2-week-old Cryptosporidium-free Peking ducklings ( Anas platyrhynchos) each received 2.0×10 6 viable Cryptosporidium serpentis oocysts from 6 naturally infected captive snakes. Histological sections of digestive (stomach, jejunum, ileum, cloaca, and cecum) and respiratory tract tissues (larynx, trachea, and lungs) did not contain life-cycle stages of Cryptosporidium in any of the inoculated ducklings. Because ducklings were refractory to infection, C. serpentis transmission via a diet of Peking ducklings is improbable. Viable (per in vitro excystation assay) inoculum-derived oocysts were detected in duckling feces up to 7 days post-inoculation (PI); the number of intact oocysts excreted during the first 2 days PI was significantly higher than for the remaining 5 days PI ( P<0.01). The dynamics of oocyst shedding showed that overall the birds released a significantly higher number of intact oocysts than oocyst shells ( P<0.01). Retention of the viability of C. serpentis oocysts following intestinal passage through a refractory avian species may have epizootiological implications. Under certain circumstances such as after the ingestion of C. serpentis-infected prey, herpetivorous birds may disseminate C. serpentis oocysts in the environment.