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FISH BORNE PARASITIC ZOONOSES
PRESENTED BY R.BHARATHI RATHINAM
AAH-MA6-07
CONTENTS• INTRODUCTION
• ZOONOSES
• IMPORTANT FISH BORNE PARASITIC ZOONOSES
• REASONS FOR PARASITIC ZOONOSES
• PREVENTIVE MEASURES
• SUMMARY
• REFERENCES
INTROUCTION
• An important public health problem.• Fish borne zoonotic cases started in late 1950s and
bloomed in 1980.• Historically very few reports are there.• Growth in aquaculture production, different diagnostic
techniques revealed this problem. “ In some parts of the world such an raw fish eating habit represents an established way of life”• Awareness needed among people about this zoonoses.
Zoonosis
• A zoonosis is any disease or infection that is naturally transmissible from animals to humans.
• Zoonosis may be bacterial, viral, or parasitic, or may
involve unconventional agents.
• Foodborne diseases caused by eating fishes which have zoonotic potential parasitic infection is called as FISH BORNE PARASITIC ZOONOSES.
• The fishborne parasites come from three main
groups:
Digenetic trematodes - especially species of the
families Opisthorchiidae and Heterophyidae;
Nematodes - mostly species of the families
Anisakidae and Gnathostomatidae;
Cestodes - species of the family
Diphyllobothriidae.
Digenetic trematodes Trematodiasis
• Hetrophyidae (Heterophyes, Haplorchis,
Metagonimus, Ascocotyle (Phagicola) and Centrocestus) – Intestinal flukes.
• Nanophyetidae – Salmon poisioning.
• Opisthorchiidae – Liver flukes (Clonorchis
sinensis, Opisthorchis viverrini and
Opisthorchis felineus).
Disease Infectious agent Acquired through consumption of
Natural final hosts of the
infection
Clonorchiasis Clonorchis sinensis FishDogs and other fish-eating carnivores
OpisthorchiasisOpisthorchis viverrini,O. felineus
Fish Cats and other fish-eating carnivores
Fascioliasis Fasciola hepatica, F. gigantica Aquatic vegetables Sheep, cattle and
other herbivores
Large number of freshwater fishes (Cyprinids- liver flukes), marine and brackishwater fishes for heterophidae.
• Integrated carp culture in earthen ponds.
• Mostly asymptomatic, high level infection cause damage in bile duct epithelium, liver, and severe cases leads to “cholangiocarcinoma” in case of liver flukes which is significant than intestinal flukes(Intestinal histopathology).
• In 2005, more than 56 million people worldwide were estimated to be infected with foodborne trematodes, and over 7000 people died from infection.
• East Asia and South America are the most affected areas. (70)
• Some species endemic to some area like Thailand , Vietnam, Russia etc (clonorchiasis to south china)
• Mild diarrhea, abdominal discomfort are the clinical signs. Diagnosis based on the eggs in stool sample.
• The public health burden to foodborne trematodiasis is due to morbidity rather than mortality.
• Irradiation of the sweetfish by 200 Gy is highly effective in controlling infectivity of metacercariae. HAACP approach to fish pond management.
Treatment can be offered through preventive chemotherapy or individual case management.
DiseaseRecommended drug and dosage
Recommended strategy
Clonorchiasis and opisthorchiasis
Individual case managementPraziquantel:– 25 mg/kg three times daily for 2–3 consecutive days
– Treat all confirmed cases – In endemic areas: treat all suspect cases
Preventive chemotherapy
Praziquantel: –40 mg/kg in single administration
– In districts where the prevalence of infection is ≥ 20%, treat all residents every 12 months– In districts where the prevalence of infection is < 20%, treat all residents every 24 months, or treat only those individuals reporting the habit of eating raw fish, every 12 months
Nematodiasis • Anisakidae and Gnathostomatidae
Anisakiasis• Herring worm disease. Caused by Squid or Raw fish eating
habit of humans.
• Humans are accidental host, and for this parasite they are dead end host.
• Diagnosis is by endoscopy, radiography.
• Symptoms: violent abdominal pain, nausea, and vomiting. In some cases, can produce allergic reactions. (An hour to two weeks after consumption)
• Most reports from Japan, Netherland, Spain.
• Diagnosis: patients vomit, immunoelectrophoresis, immunofluorescence, indirect haemagglutination etc
• Because of the reason of Humans are the dead-end host of anisakis, no treatment is needed in most cases.
• Treatment with albendazole, 400 mg twice daily for 21 days, has been used successfully in patients.
• The majority of infections involve gastric or intestinal invasion. Tissue damage occurs because of the invasion of the gut wall, development of eosinophilic granuloma and colon cancer also.
Gnathostomiasis • Humans – non required host (only for survival not
mature). Pigs, Dogs, Cats, Tigers etc. are definitive host.
• Throughout the world it is reported, but in humans mainly tropical and subtropical areas.
• Mostly through raw Freshwater fish eating habit and swallowing of infected water.
• Symptoms related to the movement of parasite through the body. It diagnosed by someone have the swelling under the skin that is move around the body. Larva migrans.
• Initially it moves through the wall of stomach or intestine or liver. (Early phase – no symptoms, 2 to 3 weeks)
• When it moves under the skin, swelling (pain). Rarely it enters other part of body includes lungs, eyes, ears and brain.
• If the parasite enters the eye – it can result in vision loss, blindness.
• People who have a parasite moves on face are at high risk.
• Two antiparasitic medications available are albendazole and ivermectin.
Cestode - Diphyllobothriasis • Diphyllobothrium latum. Largest tape worm which can infect
humans(30 feet).
• Mostly through freshwater fishes like salmon, trout, perch etc. Generally occurs in Northern hemisphere.
• Diagnosis done by stool sample egg identification.
• Abdominal discomfort, vomiting, diarrhea etc.
• Intestinal blockage is a main problem and may cause gall bladder disease
• Praziquantel or niclosamide are used mostly.
Reasons • The development of new and improved diagnosis.
• The increase in raw fish consumption – caught from polluted
or parasite prevalent areas.
• By the increased consumption of regional fish dishes such as
sushi, sashimi, ceviche, carpaccio (raw or minimally processed
fish).
• By the growth in the international market in fish and fish
products.
• By the spectacular development of aquaculture.
• A range of parasites are well adapted and have coevolved with their hosts so to persist in relationships which may be sub-clinical or even mutualistic in their nature, this would guarantee the survival of both.
• Increased pet populations.
• Climatic change – global warming.
Preventive measures
• Action on animal vectors and reservoirs.• Environmental and ecological changes.• Avoiding particular harvest areas.• Avoiding raw or undercooked consumption.• Human behaviors and education.
• Fish borne parasitic zoonosis incidences are higher now a days because of the diet and habit change of humans, climate change, technology development.
• Sushi?? , Sashmi?? And all Raw under cooked items?
• We can eat but we should ensure that the fish was caught from such a area, where the control limits of the environmental parameters met.
• And most of the parasitic initial infection were asymptotic, so if u ate raw fish then after a week, we can check ourselves for the presence of parasite.
Summary
REFERENCES• World health organization (www.who.int/)• Fishborne zoonotic parasites and aquaculture: A review by Carlos
A.M. et al., Aquaculture 318 (2011) 253–261.• Short communication “Fish-borne trematodes in cultured Nile
tilapia (Oreochromis niloticus) and wild-caught fish from Thailand, by Benjamaporn Wiriya et al., (2013).
• Fish pathology, Roberts R.J• Protozoan and metazoan diseases of finfish and shellfish, P.T.K.
Woo.• Parasites of fish and risks to public health A.M. Adams et al.,
(1997).• Invited review: “Fish-borne parasitic zoonoses: Status and issues”
Jong-Yil Chai et al., (2005).• “Infectious Disease: Anisakiasis: General” GIDEON. 20 Feb. 2010
http://web.gideononline.com/web/epidemiology/
• Notable cases, First report of human anisakidosis in Australia, By Shokoofeh Shamsi and Andrew R Butcher.
• Invited Review “Control and prevention of emerging parasitic zoonoses.” Bruno B. Chomel * WHO (2008)
• www.cdc.gov.in.
Thank you