Cryptobia

Cryptobia
Cryptobia
Scientific classification
Domain: Eukaryota
(unranked): Excavata
Phylum: Protozoa
Class: Kinetoplastida
Family: Cryptobiidae
Genus: Cryptobia
Species

Cryptobia branchialis
Cryptobia iubilans
Cryptobia salmositica
Cryptobia bullocki
Cryptobia borreli

Contents

Introduction

Cryptobia species are protozoa that can lead to disease in fish. C. branchialis is an ectoparasite that lives on the skin or gills of fish, and the other four pathogenic species are endoparasites that live in the circulatory system or intestines.

Marine and freshwater fish can be infected and the disease is most important in salmonid fish. The disease is observed in most continents including the USA, Eastern Europe and Mexico.

Bloodfeeding leeches are implicated in the transmission of the disease for those species that reside in the bloodstream.

Clinical Signs and Diagnosis

C. branchialis infects the gills and can lead to skin changes, anorexia and death.

C. iubilans resides in the intestines and leads to granulomatous inflammation in the abdominal organs resulting in weight loss and death.

C. salmositica, C. borreli and C. bullocki are all blood parasites that lead to anaemia and lesions in the haematopoietic tissues.

Skin or gill biopsies and blood samples can be examined for moving flagellated organisms.

An antibody response can be detected with ELISA testing and fluorescent antibody testing for certain Cryptobia species.

Treatment and Control

Chemical treatment has been effective using isometamidium chloride.

A vaccine against C. salmositica is available and lasts up to 2 years.

Fish can be selected and bred for resistance as a method of control of the disease.

References