Lecture 10 Flashcards
What is binamiosis caused by
Infection with Bonamia spp - an intrahaemocystic protist classified in the order of Haplosoridia
What does Bonamia. Ostreae affect
Oysters
What are signs of Bonamia
- Poor condition
- Shell gaping
- Increased mortility
- Concurrent infections also occur
- Use light microscope
What sould be sampled for Bonamia
- Gaping or freshly dead induviduals as a priority to increase the chances of finding infected oysters
How to do histology for Bonamia
Best preservation is Davidson’s AFA, but 10% buffered formalin or other standard histology fixatives are also acceptable
What are the clinical signs of Bonamia
- Dead or gaping oysters
- Increased mortality
Gross pathology of Bonamia
- Stunted growth and poor condition
- Weakened shell closure, leading to slight gaping
- Pale atrophied digestice gland
Histopathology for Bonamia
- Microcell parasites within haemocytes
- Individual microcells are basophilic, spherical or ovoid parasites, 2-3 um in diameter
When do the most mortalities happen with Bonamia exitosa
- Mid to late summer in southern hemisphere
What can affect Bonamia exitosa
- Temperature extremes
- High salinity
- Handling
- Heavy coinfection
How is Bonamia exitosa transmitted
- Via infective stages that are carried from one oyster bed to another by water currents
What is Microcytos mackini infected by
- Infection with Microcytos mackini, a intracellular protozoan that causes lethal infection
Where does Microcytos mackini reside in the cell
- Cytoplasm
What are the clinical signs of Microcytos mackini
- Dead or gaping oysters
- Increased mortality
What is the gross pathology of Microcytos mackini
- Focal yellow or green lesions up to 5mm in diamter within the body wall or on surfaces of the gonad, labial palps, gills or mantle brown scars in the shell adjacent to lesions on the mantle surface gaping oysters due to impaired adductor muscle contraction
What is the histopathology of Microcytos mackini
- Focal intracellular infection, mainly of vesicular CT cells, resulting in haemocyte infiltration and tissue necrosis intracellular and extracellular microcell protozoa, 2 to 3 um in diameter