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