DAO 40:203-209 (2000)  -  doi:10.3354/dao040203

Cytopathological observations on renal tubule epithelium cells in common carp Cyprinus carpio under Trypanoplasma borreli (Protozoa: Kinetoplastida) infection

Sabine Rudat1, Dieter Steinhagen1,*, Udo Hetzel2, Wolfgang Drommer2, Wolfgang Körting1

1Fish Diseases Research Unit and 2Pathology Department, School of Veterinary Medicine, Bünteweg 17, 30559 Hannover, Germany
*Corresponding author. E-mail:

ABSTRACT: Cytological alterations in renal tubule epithelium cells of carp Cyprinus carpio infected with the blood flagellate Trypanoplasma borreli Laveran & Mesnil, 1901 were investigated during the course of a laboratory infection of a highly susceptible carp line. With the development of the parasitaemia, a hyperplasia of the interstitial renal tissue was induced, which resulted in a tubulus necrosis. Cytological changes were already seen in tubulus epithelium cells on Day 7 post injection (PI) of the parasite. The basilar invaginations of the cells fragmented and a swelling of mitochondria was noted. With increasing parasitaemia, on Days 14 and 21 PI, these changes progressed up to the loss of the basilar invagination and high amplitude swellings of mitochondria and deterioration of their internal membrane structures. Cells of the distal tubule segment reacted earlier and more rapidly than cells of the proximal tubule. The cytological alterations suggested a loss of function of the epithelum cells, which most likely resulted in impaired ionic and osmotic regulation of T. borreli-infected fishes. Our findings indicate that in response to the proliferation of the interstitial renal tissue cell structures of the renal tubule cells are altered quickly and in a progressive manner.

KEY WORDS: Trypanoplasma borreli · Blood flagellates · Cytopathology · Tubular necrosis · Cyprinus carpio

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