Food borne animal parasites, viruses and food borne biohazards
1. Food borne animal
parasites, viruses and food
borne biohazards
Dept. of Food Science &
Technology
Wayamba University of Sri
Lanka
108072
108075
108078
108079
5. Parasites..??
• Organisms that obtain their food from other living
creatures
• Smaller than their food source and this
distinguishes them from predators which also eat
other living things
• Common food borne animal parasites - worms
and protozoa
• Worms include tapeworms (cestodes), flukes
(trematodes) and roundworms (nematodes)
6.
7. 1. Protozoan Parasites
• One-celled organisms but are larger and more
complex than bacteria
• Generally not susceptible to antibiotics that kill
bacteria but there are effective drugs to treat some
(not all) parasitic infections
• Most common types;
– Toxoplasma
– Cryptosporidium
– Entamoeba
– Giardia
8. Toxoplasma
• Toxoplasma gondii
• Obligate, intracellular, parasitic protozoan that
causes toxoplasmosis
• Infection in humans and other warm-blooded
animals can occur
– by consuming raw or undercooked meat containing T.
gondii tissue cysts
– by ingesting water, soil, vegetables, or anything
contaminated with oocysts shed in the feces of an
infected animal
– from a blood transfusion or organ transplant
– transplacental transmission from mother to fetus,
particularly when T. gondii is contracted
during pregnancy
10. Risk factors of toxoplasmosis and
preventive methods
• Diminished vision or blindness after birth of
child, more severe effects include
hydrocephalus, convulsions, and calcium deposits in
the brain
• Responsible for the deaths of AIDS patients and
causes encephalitis in many immunosuppressed
• Pregnant women and immunocompromised patients
should avoid the following:
– Raw or undercooked meat or eggs
– Unpasteurized milk, particularly goat's milk
– Contact with cat feces, including changing of cat
11. Cryptosporidium
• Mainly Cryptosporidium parvum
• Cause cryptosporidiosis, a parasitic disease of
the mammalian intestine tract
• Primary symptoms - acute, watery, and nonbloody diarrhoea
• Other symptoms -anorexia, nausea/ vomiting and
abdominal pain
• The diagnosis of C. parvum consists of serological
tests and microscopic evaluation of oocysts in
stools using Kinyoun acid-fast staining
12. • The following groups have an elevated risk of
being exposed to Cryptosporidium:
– People who swim regularly in pools with insufficient
sanitation
– Parents of infected children
– People who take care of other people with
cryptosporidiosis
– People who drink untreated water
– People, including swimmers, who swallow water from
contaminated sources
– People who handle infected cattle
– People who eat contaminated food;
meat, fish, milk, fruits and vegetables
13. Entamoeba
• Entamoeba histolytica
• An anaerobic, cause Amoebiasis
• Transmission of the parasite occurs when a person
ingests food/water that has been contaminated
with infected feces
• Cysts of the parasite are the viable form outside
the host. They can survive weeks in water, soils
and on foods under moist conditions.
• An active Entamoeba infection will cause
abdominal pain, fever, severe diarrhea, vomiting
14. • On occasion, Entamoeba is capable of traveling to
the liver
15. Giardia
• Giardia lamblia
• Single celled, flagellated, microscopic parasite
that can live in the intestines of animals and
people
• Cause giardiasis
• Giardiasis does not spread via the bloodstream,
nor does it spread to other parts of the
GI tract
16. How do people get giardiasis?
• Frequently associated with drinking
contaminated water, but some people might get
infected by consuming uncooked meat also
contaminated with G. lamblia cysts (the
infective stage of the organism)
• By putting anything into mouth that has
touched contaminated surfaces or the stool of a
person or animal with giardiasis
• Foodborne giardiasis can result from the use of
contaminated water for irrigating or washing
fruits and vegetables
17. Symptoms of giardiasis
• Most common symptoms- Diarrhea, abdominal
cramps, gas, and nausea
• Chronic infection might lead to dehydration and
severe weight loss
18. 2. Parasitic Worms
• animals that typically have a long cylindrical tubelike body and no legs
• Various types of worm occupy a small variety
of parasitic niches, living inside the bodies of
other animals.
• There are three types of worms found which act as
parasites.
– Nematoda
– Trmatoda
– Cestoda
20. Anisakis and Pseudoterranova
(Sealworm,Codworm)
• Anisakiasis was first recognized as a human
disease about forty years ago
• Found with fish
• Chub mackerel and flying squid in Japan and
pickled anchovies, raw sardines, cold smoked
salmon, raw or pickled herring are some vectors
21. • Other fish, including
whiting, mackerel, pollack, and flounder,may
also contain these parasites with anisakid
larvae
• Varies by season and increases with fish size
Water temperatures and seal populations may
also affect the abundance of these parasites
22. What’s Happened When Larvae
Are Ingested By Human ???
• Humans are an accidental host and these larvae
cannot mature in the human gut. Instead the
worms burrow into the intestinal or stomach wall
and may wander to the liver, lungs or other
tissues, causing
• Gastric disturbances and allergic reactions
larvae found in herrings body cavity
23. Ascaris lumbricoides
• Ascaris lumbricoides is a common intestinal
roundworm parasite infecting an estimated onequarter of the world’s population
• Lack of adequate hygiene could spread egg of this
nematode to people who ingest contaminated
foods and drink water
24. •
What Are The Main Causes of
Ascaris ??
Infected babies become stunts growth and
contributes to diarrheal infections and early
childhood mortality
• Infected adults do not exhibit symptoms
• these worms irritate the intestinal lining and
interfere absorption of fats and protein
• Ascaris causes more severe infections in the liver
or lungs
26. Clonorchis/Opisthorchis
(Liver flukes)
• In eastern and southeastern Asia, several related
parasitic worms of the genera Clonorchis and
Opisthorchis lodge in the liver of infected humans
and other animals causing blockage and
hyperplasia of the bile passages
27. The way of contamination occur
• Cats and several other animals are vectors
• Raw fish can spread this liver flukes
• Additionally this will be a issue to some other
countries like USA who are importing fresh water
fishes of Asian countries.
28. What happened after infection ??
• Light infections cause mild symptoms like liver
dysfunction
• Heavier infections result in hepatitis and digestive
disorders.
• According to epidemiological reviews there is
significant association between
– chronic infection
– liver cancer,
– cholangiocarcinoma
30. Taenia spp.
• Most familiar worm found in intestine of human
when they re infected
• There are number of species which used several
animals as human, dog, even beares as there hosts
31. • T. solium, in particular, may be present in as many
as 20% of hogs
• Causes debilitating human disease that is difficult
and expensive to treat
32.
33. How is it infected ??
• Via dirty hands
• Fecally contaminated vegetables
• Contaminated water or foods
35. Problems related with infection
• Cysticercosis
• The most serious consequences occur when the
larvae reach the brain, causing neurocysticercosis
• often triggers
– headaches, seizures, and other neurological
symptoms
37. Characteristics
– Small microorganism
– Parasites that replicate/ propagate themselves
within suitable living host cells
– Do not reproduce in food
– Spread usually result of poor hygiene
– Relatively stable and acid resistant outside host
cells
39. 1. Hepatitis A virus
• Infection
• Incubation: 10-50 days
• Deceases called as Hepatitis A
Infection in humans occur
– Eat or drink food or water that has been
contaminated by feces containing the hepatitis A
virus (fruits, vegetables, shellfish, ice, and water)
– Contact with the feces or blood of a person who
currently has the disease
40. – A person with hepatitis A does not wash his or
her hands properly after going to the bathroom
and touches other objects or food
– Participate in sexual practices that involve oralanal contact
Virulence Mechanisms:
– Ingest virus through food/water/fomite
– Possibly infects intestinal cells
– Moves to liver
– Does not kill liver cells
– Immune response - T-cell destruction of
infected cells
– Virus excreted in bile, then faces
41. Hepatitis A cont.…
Symptoms: 2 - 6 weeks after being exposed to the
hepatitis A virus
– systemic infection characterized by
gastrointestinal manifestations and liver injury
•
•
•
•
•
Sudden fever
Vomiting
Jaundice
abdominal discomfort and bile in urine (Dark urine)
Fatigue
42. 2. Rotavirus
• Infection
• Incubation: 1-3 days
• Inflammation of the stomach and intestines
Infection in humans occur
– Ingestion of contaminated food or water
– Direct contact with contaminated surfaces and
then putting the hands in the mouth
43. Virulence Mechanisms:
• Infects cells that line the small intestine cells
• Produces enterotoxin
• Induces gastroenteritis
• Severe diarrhea and sometimes death through
gastroenteritis
Symptoms:
– Fever
– Stomach cramps
– vomiting, and diarrhea
– Dehydration
44. 3. Norwalk Virus
• Infection
• Incubation: 12 to 48 hours
• Infection of the stomach and intestines
Transitions:
– Ready to eat foods, molluscs and uncooked
– eating food or drinking liquids that are
contaminated with norovirus,
– Touching surfaces or objects contaminated with
norovirus then putting your fingers in your
mouth, or
– Touched infected workers or any other foods
contaminated with vomit or feces from an
infected person
45. • Symptoms :
– Nausea
– Vomiting (more often children)
– Diarrhea (more often adults)
– Anorexia
– Low grade fever, aches, chills, malaise
• Recovery: 12 to 60 hours usually
• Shedding up to 1 week! (feces, vomit)
46. Virulence Mechanisms:
– Eat or drink food or water that has been
contaminated by feces containing the hepatitis
A virus (fruits, vegetables, shellfish, ice, and
water)
– Contact with the feces or blood of a person
who currently has the disease
– A person with hepatitis A does not wash his or
her hands properly after going to the bathroom
and touches other objects or food
– Participate in sexual practices that involve oralanal contact
48. Biotoxins
• Biotoxin is a poisonous substance that is a specific
product of the metabolic activities of a living
organism (Plant, animal, bacteria, fungus)
• Cause food intoxications
• Toxicity depends on dose
49. Food Intoxication
• Microbes grow in foods produce toxins
• Toxins are ingested with the food and cause health
problems
• Most heat treatments are effective to kill
microbes, but toxins remain
59. How to control
• Good agricultural practices to avoid insect
damages and mold infection
• Good storage practices (Store below 100C, control
moisture, control RH)
• Separation of contaminated foods before
processing
60. How to control
• Follow proper food handling and canning
methods
• Maintain good hygienic practices
• Rules and Regulations