2. SOURCE & FACTORS RELATED
TO FISH & SHRIMP DISEASE IN BD
• Presented By
SUMON KUMAR AUDHIKARY ASH1502024M
MUJAHIDUL ISLAM ASH1502034M
MD. TAHMIDUL HAQUE ASH1502045M
RAJU DAS ASH1502052M
MD. ASRAFUR RAHMAN ASH1402072M
3. INTRODUCTION
Disease is a prime agent affecting fish mortality.
Different factor are responsible for producing disease of fish and
shrimp including environmental factors, Hereditary factor, mechanical
injury etc.
Fish defenses against disease are specific and non-specific.
Non-specific defences include skin, scales and mucus layer.
Specific defences includes adaptative immune responses.
4. IMPORTANCE OF STUDY SOURCE AND FACTOR OF
FISH AND SHRIMP DISEASE AS A
FISHERIES STUDENT
Can know about the pathogen which cause fish disease.
Can know about source of disease causing pathogen.
Can know about the factors which are favorable growth of
microorganism.
5. SOURCE OF FISH AND SHRIMP DISEASE IN BD
Infection:
Infection is the invasion of an organism's body tissues by disease-causing agents,
their multiplication, and the reaction of host tissues to the infectious agents and
the toxins they produce. Infectious disease, also known as transmissible
disease or communicable disease, is illness resulting from an infection.
6. SOURCES OF INFECTION
1. Direct or immediate contact with diseases producing organisms.
2. Diseases carrying organisms
3. Contact with soil
4. Secondary infection
5. Water bone infection
6. Direct entry of pathogen
7. Migration or travel
8. Contamination by different sources
9. Contact with pollution
10. Other sources in fish Disease
7. 1. DIRECT OR IMMEDIATE CONTACT WITH
DISEASES PRODUCING ORGANISMS
These factors may be pathogenic, non-pathogenic or
environmental.
Fish may weak or due to infected by bacteria, viruses,
oxygen depletion, temperature, water pollution etc.
Directly transmitted parasites, not requiring a vector to
reach their hosts, such as lice and mites.
8. 2. DISEASES CARRYING ORGANISMS:
These organisms may be predator or prey- small fishes, aquatic birds, snakes, frogs etc.
When infested predators attack the fishes then fishes are infected by this predator
When fishes fallen infected insects, small fishes, snakes or plankton as food then they
may be infected.
Here a transmission of pathogens horizontal. This may be due to unsuccessful attack of
predators or feed on infected prey.
9. 3. CONTACT WITH SOIL
a) Soil microbes:
Soils harbor enormous microbial diversity,
comprising bacteria, archaea, and fungi.
The total fresh weight mass of organisms in
grassland soils can exceed 45 tones per hectare,
equaling or exceeding above-ground biomass.
b) Toxic substances of soil
Soil contamination or soil pollution as part
of land degradation
It is caused by the presence
of xenobiotic (human-made) chemicals or other
alteration in the natural soil environment.
It is typically caused by industrial activity,
agricultural chemicals, or improper disposal
of waste.
10. 4. SECONDARY INFECTION:
The primary infection makes an organism
more susceptible to disease.
It is called a secondary infection because it
occurs either after or because of another
infection.
Secondary infection is caused by bacteria,
fungus, etc. various factors are responsible
for secondary infections
such as injury by of fish by angling, netting,
rough handling or parasites infection etc.
11. 5. WATER BONE INFECTION:
Water borne diseases are conditions caused by pathogenic micro-organisms that are
transmitted in water.
Disease can be spread while bathing, washing or drinking water, or by eating food
exposed to infected water.
12. 6. DIRECT ENTRY OF PATHOGEN:
Invasiveness is the ability of a pathogen to invade tissues. Invasiveness encompasses
(1) Mechanisms for colonization (adherence and initial multiplication)
(2) Production of extracellular substances ("invasins"), that promote the immediate
invasion of tissues and
(3) Ability to bypass or overcome host defense mechanisms which facilitate the actual
invasive process.
13. 7. MIGRATION OR TRAVEL
During migration fishes don’t take any food.
As a result they become weak at that period or time and so the chances of infection
increase by pathogen.
Besides a physiological change occur at environment during migration and fishes
may be infected by new pathogen or infecting agents.
14. 8. CONTAMINATION BY DIFFERENT SOURCES
Fishes may be contaminated by –
Contaminated food.
Contact with contagious disease animal
Drinking of water
15. 9. CONTACT WITH POLLUTION
Various insecticides, herbicides, toxic substances, industrial waste product, heavy
metals etc.
All this substances polluted the environment and in the meantime fish may be
infected by this polluted environment.
These are the rich sources of various pathogen and toxic substances which ultimately
cause infection in fishes.
16. 10. OTHER SOURCES IN FISH DISEASE:
I. Few fish viruses are known to be vectored by arthropods.
II. Water is a stabilizing medium, but currents are less effective for long range virus
transmission then are aerosols.
III.Wild reservoir species are often at very low densities
IV. Fish are poikilothermic and temperature has an exceptionally critical role in
modulating the disease process by affecting both the replication rate of the virus
as well as the host immune response.
V. Few fish viruses are transmitted sexually between adults, although high levels of
some viruses are present in spawning fluids.
VI.A few viruses are transmitted vertically from adult to progeny, either intra-ovum
or on the egg surface.
VII.For avian diseases, migratory fish can serve as carriers for long-range dispersal
of viral pathogens.
17. FACTORS AFFECTING FISH AND SHRIMP
DISEASES
• A. Environmental factor
• B. Hereditary factors
• C. Glandular dysfunction
• D. Mechanical injury
• E. Pathogenic organism
• F. Atypical cell growth
• G. Dietary deficiency factors
21. GLANDULAR DYSFUNCTION
1. Impaired function of spleen
2. Thyroid
3. Pancreas
4. Pituitary etc.
5. Giving rise to pain syndrome
6. Pcod
7. Hypothyroidism
8. Diabetes
9. The efficiency of iron and iodine leads to thyroid.
22. MECHANICAL INJURY
• Mechanical injury initially resulted in edema, telangiectasia,
hemorrhaging and leucocytic infiltration.
23. PATHOGENIC ORGANISM
• A germ in the oldest and
broadest sense is anything that
can produce disease.
• There are several substrates
including pathways where the
pathogens can invade a host.
• Diseases caused by organisms
in fishes are known as
pathogenic diseases.
24. ATYPICAL CELL GROWTH
• The presence of atypical cells is
sometimes referred to as "dysplasia."
• Many factors can make normal cells
appear atypical, including
inflammation and infection.
• Atypical cells can change back to
normal cells if the underlying cause is
removed or resolved.
25. DIETARY DEFICIENCY FACTORS
1)Carbohydrate deficiency
Less metabolic balance.
Less ovarian or egg development.
Disturbance in swimming.
2)Fat deficiency:
Migratory fish stop migration.
Egg laying capacity inhibited.
Energy metabolism stops.
27. DIETARY DEFICIENCY FACTORS (CONT…)
4) Vitamin deficiency
Due to insufficient vitamins, fish are
suffered from several disease.
• Vitamin A-----Exophthalmia
• Vitamin D-----Lower hemoglobin.
• Vitamin F-----Anemia.
• Vitamin K-----Blood do not coagulate.
Exophthalmia
Anemia
28. RECOMMENDATIONS
Identification of important pathogens for fish and shrimp.
Strategies for avoiding introduction of pathogens.
Controlling spread of pathogens within facilities.
Quarantine.
29. CONCLUSION
Different factor are responsible for producing disease of fish and shrimp
including environmental factors (temperature, pollution, DO, salinity, pH,
predation, pathogen and parasite ), Hereditary factor (Tumors, Albinism,
Dropsy), Mechanical injury etc.
Fish defenses against disease are specific and non-specific. Non-specific
defenses include skin and scales, as well as the mucus layer secreted by the
epidermis that traps microorganisms and inhibits their growth.
