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Published on: December 8, 2017
Pleistophora hyphessobryconis (Microsporidia) infecting zebrafish Danio rerio in research facilities
Justin L Sanders1, Christian Lawrence, Donald K Nichols
1Department of Microbiology, Oregon State University, Corvallis, Oregon 97331, USA. justin.sanders@oregonstate.edu
Abstract:
Zebrafish Danio rerio are important models for biomedical research, and thus, there is an increased concern about diseases afflicting them. Here we describe infections by Pleistophora hyphessobryconis (Microsporidia) in zebrafish from 3 laboratories. As reported in other aquarium fishes, affected zebrafish exhibited massive infections in the skeletal muscle, with no involvement of smooth or cardiac muscle. In addition, numerous spores within macrophages were observed in the visceral organs, including the ovaries. Transmission studies and ribosomal RNA (rRNA) gene sequence comparisons confirmed that the parasite from zebrafish was P. hyphessobryconis as described from neon tetra Paracheirodon innesi. Ten 15 d old zebrafish were exposed to P. hyphessobryconis collected from 1 infected neon tetra, and 7 of 10 fish became infected. Comparison of P. hyphessobryconis small subunit rRNA gene sequence from neon tetra with that obtained from zebrafish was nearly identical, with < 1% difference. Given the severity of infections, P. hyphessobryconis should be added to the list of pathogens that should be avoided in zebrafish research facilities, and it would be prudent to avoid mixing zebrafish used in research with other aquarium fishes.
Insights
Microsporidia infections by Pleistophora hyphessobryconis are a serious concern for zebrafish (Danio rerio) biomedical research. This parasite, confirmed via rRNA gene sequencing and transmission studies, can severely impact research models.
Area of Science:
- Aquatic Animal Health
- Parasitology
- Zebrafish Models in Research
Background:
- Zebrafish (Danio rerio) are crucial biomedical research models, raising concerns about diseases affecting them.
- Pleistophora hyphessobryconis (Microsporidia) infections have been identified in zebrafish across three research laboratories.
- Affected zebrafish present with skeletal muscle infections, while smooth and cardiac muscles remain unaffected.
Purpose of the Study:
- To identify and characterize Pleistophora hyphessobryconis infections in zebrafish.
- To confirm the parasite's identity and transmission dynamics.
- To provide recommendations for preventing parasite spread in research facilities.
Main Methods:
- Histopathological examination of infected zebrafish tissues.
- Transmission studies exposing zebrafish to P. hyphessobryconis from infected neon tetra.
- Ribosomal RNA (rRNA) gene sequence comparison between parasite isolates.
Main Results:
- Zebrafish exhibited massive skeletal muscle infections with P. hyphessobryconis spores.
- Spores were also found within macrophages in visceral organs, including ovaries.
- Transmission studies confirmed P. hyphessobryconis infectivity in zebrafish (7/10 infected).
- rRNA gene sequence analysis showed <1% difference between neon tetra and zebrafish isolates, confirming species identity.
Conclusions:
- P. hyphessobryconis is confirmed as the causative agent of microsporidiosis in the studied zebrafish.
- The parasite is highly infectious to zebrafish and can cause severe systemic disease.
- P. hyphessobryconis should be considered a significant pathogen in zebrafish research facilities, necessitating strict biosecurity measures.
- Avoiding cohabitation of research zebrafish with other aquarium fish is recommended to prevent transmission.
