National Aquatic Life Disease Control System and Aquatic ... · National Aquatic Life Disease Control System and Aquatic Animal Diseases Myoung Ae PARK ... (such as fish, molluscs,

National Aquatic Life Disease Control System and Aquatic Animal Diseases

Myoung Ae PARK

[email protected]

Introduction to National Aquatic Life

Disease Control System

1. The aim of act is to assure the prevention of outbreak and spread of

aquatic animal diseases in Korea.

2. Control measure of diseases are notification of aquatic animal diseases,

surveillance, disinfection or destruction, risk analysis and quarantine.

3. The notifiable diseases are 8 kinds in fishes, 5 kinds shellfish and 7

kinds in crustacean.

4. The confirmed disease by qualified diagnostic laboratories would be in

forced monitoring, surveillance, movement control or stamping out.

5. All live aquatic animals(such as fish, molluscs, shrimp) or eggs or

gametes have to be declared free from listed diseases for importation

into Korea.

Class Name of infectious disease Disease control measure

contaminated

contaminated

contaminated

Fish inspector, Veterinarian

Autholized diagnosis Lab

Local governments

Fish farms

NFQS National Fishery Products

Quality Management Service

5. Constitutions for Disease Control

NIFS National Institute of Fisheries

Science

7. Main Functions of Aquatic Diseases Control Division

Establishing disease control infrastructure

Developing and enforcing a control program

Surveillance and control of risk factor

Contagious disease inspection of releasing aquatic animal

Operating aquatic animal disease control network

Developing / researching the disease control

Improving and control of risk factor

Autholized

Diagnostic Lab. Local Government,

University

(13)

NIFS Aquatic life

disease control division

Private

Clinic Specialist

Standard Manual, Auditing, Education and Training

Current Diseases in Aquatic Animals

Aquaculture trends

Increasing intensification:

- more disease outbreaks and disease emergencies

Continued diversification of species

- Increased risk of introduction and spread of pathogens (Trans-

boundary pathogens)

Continued diversification of farming systems

- Potential for spread of pathogens to wider geographical areas

Economic and social cost of disease is enormous

(e.g/ One billion $ annual loss in China)

Infectious Disease

Viral Disease

Bacterial Disease

Parasitic Disease

Fungal Disease

Non-infectious Disease

Nutritional disease • Nutritional ceroid lipofuscinosis:

..Stop supply of the rancid and deteriorated feeds, and supply nutritionally balanced feed with vitamin E, C, glutathione, etc. • Vitamin Deficiency:

..While vitamins are divided into water-soluble and lipid-soluble, these vitamin deficiency causes various pathological symptoms. Thus, it is recommended to mix feed with vitamin supplements and supply.

Non-infectious Disease

Environmental disease

- Too much e.g. ammonia - Too little e.g. O2

- Nitrite Poisoning

.. Body color change, Abdominal distention, Browning of gills and blood, Anemia

.. Prevention: Water exchange (25-50%), Chloride (Cl-) addition, reduction of rearing density, water temperature, feed supply.

- Stress: Causes of stress include rapid water temperature change, vibration, high density culture, and stocking of fish in various sizes in one tank.

Disease Transmission

Vertical - Pathogen in the parent fish transmit infection

to the fertilized egg

- Pathogen in the parent fish is released into

the water during spawning.

Horizontal - Rearing water

- Contact: infection through direct or indirect

contact with infected fish

- Carrier animal: Infection by predation of

pathogen-bearing carriers

Pathogen

Frequency: 5% (1990’s) 20% (present)

Diseases: bacterial diseases complex diseases

Season: summer (high temperature) whole year

Iridovirus

Iridovirus

Status of Finfish Diseases

Finfish Diseases

Pathogen: Iridovirus

Target species: Parrot fish,

Sea breams, sea bass

Outbreak period: High temp season

(July-Oct, above 20℃)

Symptom: Body discoloration,

enlargement of spleen, congestion

in eyes

Iridoviral infection

Mass mortality occurred on adult

flounder on the southern coast of

Korea (2005-present)

Symptom: Muscle haemorrhaging,

rectal hernia, expanded abdomen

due to ascites and a congested liver

Pathogenicity: Causing mass

mortality below 15℃

Fish Diseases

Viral Hemorrhagic Septicemia, VHS

First outbreak : cage culture farms located in various areas in Korea during early summer in 1998.

Carp, especially common carp and Israel carp

were affected and killed.

Mortality was found to be sudden and acute, and was found to affect fish of all ages.

OIE notifiable disease

Can cause mortalities up to 70% in younger fish

Koi Herpes Virus, KHV

Fish Diseases

Gills of diseased carp produce

excess mucus and have necrotic lamellae.

Decoloration is also found in the gills .

Pathogen: Edwardsiella tarda

Target organism: Flounder,

red sea bream

Outbreak period

- Before: High temp season

(July-Oct)

- Recent: All the year round

Symptom: Expanded abdomen,

rupture, darkness and ascites

Fish Diseases

Edwardsiellosis

Streptococcosis

• Pathogen: Streptococcus iniae, S. parauberis, Lactococcus garvieae • Target species: Flounder, Rock fish, Yellow tail, Red sea bream • Outbreak: High temp. season (July-Nov) • Symptom: Haemorrhages within the opecular cavity, abdomen and internal organs, ascites, enlargement of the spleen

Fish Diseases

Pathogen: Uronema marinum

Target species: flounder, sea bass etc.

Outbreak period

- Before: Late autumn to early spring

- Recent: All the year round

Symptom: ulcers in anus and back,

congested head

Scuticociellosis

Fish Diseases

Uronema marinum isolated from

Ulcerative lesion on flounder

Disease Prevention

What is disease prevention ?

- Prevention includes preventive measures against infestation and spread of infectious diseases

- Quarantine to prevent infectious diseases from entering foreign countries is a part of prevention

- Disinfecting aquaculture equipment is a part of prevention

Disease prevention methods - Disinfection of breeding equipment, restricting outsiders' access to farms, and testing for disease when purchasing seedlings.

- The disease prevention at fish farm is the first starting point

Shellfish Diseases

Hosts: European oyster (Osterea edulis, O. puelchana, O. angasi, O. chilensis,

O. conchaphila), Asian oyster (Crassostrea angulata,

C. ariakensis)

Characteristics

- Highly contagious in individuals older than 2 years

- It may cause fatal infection on hemocyte of oyster.

- The oyster turned yellow and extensive lesions are formed in

gills and muscle.

- Most infected oysters have normal appearance

- Infection occurs throughout the year, but the degree of infection

tends to be high in high temperature period, especially autumn.

Geographical Distribution

Europe (France, Ireland, Italy, Netherlands, Spain, UK), Canada,

USA etc.

Bonamia Infection (Bonamia ostreae)

Hosts: Osterea edulis, O. chilensis, O. puelchana,

O. angasi, Mytilus edulis

Characteristics

- Infection on epithelial cells such as stomach, digestive tract, gill, etc.,

resulting in tissue destruction, leading to growth failure due to

glycogen loss

- Infection occurs in spring and summer, and is more frequent in

oysters over 2 years of age

Geographical Distribution

Europe, including France, Greece, Italy, Morocco, Spain and

Portugal

Marteilia Infection (Marteilia refrigens)

Shellfish Diseases

Moderate intensity (arrow) of Polydora sp.

(mud worm) tunnels on inner shell surface of

oyster C. virginica.

“Maladie du pied” (arrow) covering much

of muscle scar on inner shell surface of

oyster C. virginica.

Shell Abnormalities

Shellfish Diseases

Symptoms

- Swollen mouth and around tissue of infected abalone.

In severe case, the mouth tissues fall-out from the body.

- Contraction and muscle stiffness of tissue

- Tissue necrosis with infiltration of haemocytes due to

nerve cell infection

Characteristics

- Mortality rate of 70-100% within 3-5 days after infection

- It mainly occurs in China, Taiwan and Australia

Abalone Herpesvirus

Shellfish Diseases

Polychaeta Infection

Cause:

Polydora sp. (Parasitic Polychaeta of Annelida)

It inhabits in the contaminated area where there are abundant organic

matters. After entering the aquaculture farm, it penetrates the shell of the

abalone and inhabits in the shell.

Symptoms:

Infected individuals climb weakly on the wall, and generally shows

reduced overall growth rate.

In case of severe infection, it may cause cumulative mass mortality,

which shows mortality rate of approximately 30% of the total number

of fish.

Shellfish Diseases

Polychaeta Infection

Shellfish Diseases

Characteristics:

Since most of the abalone fish farms are

densely concentrated, the frequency of

Polychaeta infection goes high when abalone is cultured in long period.

Preventive Measures:

Unlike other parasites that can be treated with medicines,

once inside the shell, they are hidden in the shell and not

released outside environment.

Not curable with medicines

Management of Diseases

• No vaccines, and treatments difficult to apply

• Health management in impacted zones

• In an area free of a disease, the key point is to avoid any introduction of infected stocks

– standards, guidelines and recommendations are provided at international, regional and national levels

– efforts have been made to improve diagnostic methods for diseases of molluscs

– however, transfers are not the unique route of disease introduction or emergence

National Institute of Fisheries Science

Transmission route of WSD

1992

1995

1994

1994

1993

1993 U.S.

1996

Crustacean Diseases

White Spot Disease (WSD)

Crustacean Diseases

• HOSTS: All penaeids, >50 crustacean hosts

• PATHOGEN: dsDNA virus, Nimaviridae, 1992 China

• VECTORS: Infected live and frozen shrimp, secondary hosts (>50 known)

• DISTRIBUTION: Asia, Pacific coasts of Central & South America,

Gulf of Mexico, Atlantic coast of S. Carolina, HI and Brazil

• CLINICAL SIGNS: Lethargy, anorexia, rapid death, dark color, “white spots” in P. monodon exoskeleton

• EFFECT: Mortality reaching 100%, severe economic loss

Taura Syndrome Virus (TSV)

• HOSTS: P. vannamei, P. stylirostris; PL to early juvenile.

• CAUSATIVE AGENT: ssRNA, Dicistrovirus, 1992 Ecuador,

4 strains identified to date. Vertical transmission not demonstrated.

• VECTORS: Infected live/frozen shrimp, Marine birds,

Water boatmen (T. reticulata)

• DISTRIBUTION: W. hemisphere, Taiwan, Thailand, Indonesia, China.

• CLINICAL SIGNS: Lethargy, anorexia, difficulty swimming, dark color, flaccid, opaque musculature, survivors w/ black spots.

• EFFECT: Mortality 60-95%.

Crustacean Diseases

Infectious Myonecrosis (IMN)

Pathogen: Infectious myonecrosis virus(IMNV) (includes in Totiviridae)

Hosts: White leg shrimp (Litopenaeus vannamei), Blue shrimp (L. stylirostris), Green tiger shrimp (Penaeus semisulcatus)

Geographical distribution: Brazil, Indonesia, China, etc.

Symptoms - External: Weakness, stress-sensitive, local or extensive muscle

necrosis, red coloring - Internal: Hypertrophy of lymphoid organ - Typical muscle necrosis during acute phase and high mortality, but it shows low mortality in chronic stage

Crustacean Diseases

AHPNS Acute Hepatopancreatic Necrosis Syndrome

‘09

‘10

‘11

‘12

China‘09 outbreak

Vietnam10 outbreak

Malaysia‘11 outbreak

Tailand‘12 outbreak

Crustacean Diseases

Characteristic of AHPNS - Mass mortality within 30days after stocking

- Higher intensification

- At farms with poorly prepared ponds (no sludge removal)

- Poor management leading to excess nutrient pollution

- At older farms close to the sea

- When seed experiences stress during transportation

Crustacean Diseases

Shrimp health management

Focus on prevention

Highly efficacy vaccine development

Development of immunostimulants

Standardization of diagnostic methods

Development of disinfection protocols

to contain the spread of pathogenic

diseases

Future

Treatment by antibiotics [ problems ]

• Increased antibiotics resistance bacteria

• Food safety threats by residual antibiotics

• Mixed infection

• Viral disease

Present

Further Research Trends