Gaffkaemia
Encyclopedia
Gaffkaemia is a bacteria
l disease of lobster
s, caused by the Gram-positive
lactic acid bacterium
Aerococcus viridans var. homari.
s (Homarus americanus) in a holding tank in Maine
. It was originally described as "Gaffkya homari" by Hitcher and Snieszko, but the genus name Gaffkya was rejected in 1971, and the gaffkaemia bacterium was recognised as a subspecies or variety of Aerococcus viridans by Kelly and Evans in 1974.
and a pink colour on the ventral side of the abdomen
, which gives the disease its alternative common name of red tail disease. When lobsters are moribund, they may lie on their sides, and frequently lose appendage
s. The effects of gaffkaemia are slowed by low temperatures, such that death can occur within two days of infection at 20 °C (68 °F), but can take over 60 days at 3 °C (37.4 °F).
As few as five bacteria can lead to clinical disease. When they enter the host, the bacteria colonise the heart
and hepatopancreas
. They may be engulfed by phagocytosis into the lobster's blood cells, but continue to survive within the blood cells, feeding on the cytoplasm
. The lobster's blood cell count drops, and the infection develops into septicaemia. The stores of glycogen
in the hepatopancreas become depleted, concentrations of glucose
and lactic acid
in the blood drop, and concentrations of adenosine triphosphate
(ATP) in muscle
s also fall. In a severe infection, the ability of the lobster's blood pigment haemocyanin to carry oxygen
may be reduced by up to 50%.
is to culture aliquot
s of haemolymph in phenylethyl alcohol broth. Cultures containing A. viridans var. homari change colour from purple to yellow, and form tetrads of cocci
. To reduce the four-day waiting time needed for diagnosis, a method using the indirect fluorescent antibody technique (IFAT) was developed, and, more recently, PCR
-based methods have been developed.
in North America
, and causes little harm to wild populations of H. americanus. In the European or common lobster, Homarus gammarus, however, it is far more destructive. European lobsters held in the same tanks as American lobsters can be killed within days. A number of other crustacean species can be infected with A. v. var. homari, but do not develop severe disease. They include the shrimp
Pandalus platyceros
, and the crabs Cancer borealis, Cancer irroratus
, Metacarcinus magister, Libinia emarginata, Chionoecetes opilio
and Chaceon quinquedens. Spiny lobster
s appear to be either immune or resistant to gaffkaemia.
(preventing the bacterium's entry), reducing the water temperature, and reducing the stocking density. Antibiotic
s may be effective against the bacterium, but only tetracyclin is currently approved by the Food and Drug Administration
for use in American lobsters.
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
l disease of lobster
Lobster
Clawed lobsters comprise a family of large marine crustaceans. Highly prized as seafood, lobsters are economically important, and are often one of the most profitable commodities in coastal areas they populate.Though several groups of crustaceans are known as lobsters, the clawed lobsters are most...
s, caused by the Gram-positive
Gram-positive
Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain and appearing red or pink...
lactic acid bacterium
Lactic acid bacteria
The lactic acid bacteria comprise a clade of Gram-positive, low-GC, acid-tolerant, generally non-sporulating, non-respiring rod or cocci that are associated by their common metabolic and physiological characteristics. These bacteria, usually found in decomposing plants and lactic products, produce...
Aerococcus viridans var. homari.
Discovery
Gaffkaemia was first discovered in 1947 in American lobsterAmerican lobster
The American lobster, Homarus americanus, is a species of lobster found on the Atlantic coast of North America, chiefly from Labrador to New Jersey. Within North America, it is also known as the northern lobster or Maine lobster. It can reach a body length of , and a mass of over , making it the...
s (Homarus americanus) in a holding tank in Maine
Maine
Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...
. It was originally described as "Gaffkya homari" by Hitcher and Snieszko, but the genus name Gaffkya was rejected in 1971, and the gaffkaemia bacterium was recognised as a subspecies or variety of Aerococcus viridans by Kelly and Evans in 1974.
Effects
The effects of gaffkaemia infection include lethargy (typically seen as a drooping tail), anorexiaAnorexia (symptom)
Anorexia is the decreased sensation of appetite...
and a pink colour on the ventral side of the abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
, which gives the disease its alternative common name of red tail disease. When lobsters are moribund, they may lie on their sides, and frequently lose appendage
Appendage
In invertebrate biology, an appendage is an external body part, or natural prolongation, that protrudes from an organism's body . It is a general term that covers any of the homologous body parts that may extend from a body segment...
s. The effects of gaffkaemia are slowed by low temperatures, such that death can occur within two days of infection at 20 °C (68 °F), but can take over 60 days at 3 °C (37.4 °F).
As few as five bacteria can lead to clinical disease. When they enter the host, the bacteria colonise the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
and hepatopancreas
Hepatopancreas
The hepatopancreas, digestive gland or midgut gland is an organ of the digestive tract of arthropods, molluscs and fish. It provides the functions which in mammals are provided separately by the liver and pancreas, including the production of digestive enzymes, and absorption of digested...
. They may be engulfed by phagocytosis into the lobster's blood cells, but continue to survive within the blood cells, feeding on the cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...
. The lobster's blood cell count drops, and the infection develops into septicaemia. The stores of glycogen
Glycogen
Glycogen is a molecule that serves as the secondary long-term energy storage in animal and fungal cells, with the primary energy stores being held in adipose tissue...
in the hepatopancreas become depleted, concentrations of glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
and lactic acid
Lactic acid
Lactic acid, also known as milk acid, is a chemical compound that plays a role in various biochemical processes and was first isolated in 1780 by the Swedish chemist Carl Wilhelm Scheele. Lactic acid is a carboxylic acid with the chemical formula C3H6O3...
in the blood drop, and concentrations of adenosine triphosphate
Adenosine triphosphate
Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...
(ATP) in muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
s also fall. In a severe infection, the ability of the lobster's blood pigment haemocyanin to carry oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
may be reduced by up to 50%.
Diagnosis
The classical method of diagnosisDiagnosis
Diagnosis is the identification of the nature and cause of anything. Diagnosis is used in many different disciplines with variations in the use of logics, analytics, and experience to determine the cause and effect relationships...
is to culture aliquot
Aliquot
Aliquot may refer to:In mathematics:*Aliquot part, a proper divisor of an integer*Aliquot sum, the sum of the aliquot parts of an integer*Aliquot sequence, a sequence of integers in which each number is the aliquot sum of the previous numberIn music:...
s of haemolymph in phenylethyl alcohol broth. Cultures containing A. viridans var. homari change colour from purple to yellow, and form tetrads of cocci
Coccus
Coccus can be used to describe any bacterium that has a spherical shape. It is one of the three distinct types of bacteria shapes, the other two being bacillus and spirillum cells...
. To reduce the four-day waiting time needed for diagnosis, a method using the indirect fluorescent antibody technique (IFAT) was developed, and, more recently, PCR
Polymerase chain reaction
The polymerase chain reaction is a scientific technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence....
-based methods have been developed.
Virulence
Gaffkaemia is enzooticEnzootic
Enzootic is the non-human equivalent of endemic and means, in a broad sense, "belonging to" or "native to", "characteristic of", or "prevalent in" a particular geography, race, field, area, or environment; native to an area or scope....
in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, and causes little harm to wild populations of H. americanus. In the European or common lobster, Homarus gammarus, however, it is far more destructive. European lobsters held in the same tanks as American lobsters can be killed within days. A number of other crustacean species can be infected with A. v. var. homari, but do not develop severe disease. They include the shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
Pandalus platyceros
Pandalus platyceros
Pandalus platyceros, also called California spot prawn or Alaskan prawn, is a shrimp of the genus Pandalus.Spot shrimp are a large shrimp found in the North Pacific...
, and the crabs Cancer borealis, Cancer irroratus
Cancer irroratus
Cancer irroratus, common name the Atlantic rock crab, or peekytoe crab, is a crab in the genus Cancer. Other local names are Maine crab, bay crab, sand crab and mud crab. It has nine marginal teeth on the front edge of the carapace beside each eye....
, Metacarcinus magister, Libinia emarginata, Chionoecetes opilio
Chionoecetes opilio
Chionoecetes opilio is a predominantly epifaunal crustacean found at shelf depths in the northwest Atlantic Ocean and north Pacific Ocean. It is a well-known commercial species of Chionoecetes, often caught with traps or by trawling. Male C. opilio with a total length above long are the most...
and Chaceon quinquedens. Spiny lobster
Spiny lobster
Spiny lobsters, also known as langouste or rock lobsters, are a family of about 45 species of achelate crustaceans, in the Decapoda Reptantia...
s appear to be either immune or resistant to gaffkaemia.
Control
The primary method for controlling the incidence of gaffkaemia is improved hygiene. Other measures include limiting damage to the exoskeletonExoskeleton
An exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...
(preventing the bacterium's entry), reducing the water temperature, and reducing the stocking density. Antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s may be effective against the bacterium, but only tetracyclin is currently approved by the Food and Drug Administration
Food and Drug Administration
The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...
for use in American lobsters.