PUBLIC HEALTH SIGNIFICANCE OF Vibrio parahaemolyticus its importance and effect in fish, shellfish, as well as human beings

1. West Bengal university of animal and fishery sciences
A Seminar on
AAH-323
PUBLIC HEALTH SIGNIFICANCE :
Vibrio parahaemolyticus
PRESENTED TO,
PROF. T.J.ABRAHAM
DEPT OF AAH
SUBMITTED BY,
RAJESH MANDAL
B.F.SC 3rd YEAR 2nd SEM
F/2015/24

2. INTRODUCTION
Vibrio parahaemolyticus is a bacterium that occurs naturally in coastal marine waters and
estuaries. It is recognized world-wide as a significant cause of bacterial seafood-borne
illness. The United States Centers for Disease Control and Prevention (CDC) estimates that
of the approximately 7,880 Vibrio illnesses each year in the United States, approximately
2,800 are estimated to be associated with Vibrio parahaemolyticus and raw oyster
consumption. Vibrio parahaemolyticus is normally present in many types of raw seafood,
including fish, crustaceans, and molluscan shellfish. It multiplies and colonizes in the gut of
filter-feeding shellfish such as oysters, clams, and mussels. Not all strains of Vibrio
parahaemolyticus cause illness; on the contrary, pathogenic strains represent a small
percentage of the total Vibrio parahaemolyticus present in the environment or seafood.

3. Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Gamma Proteobacteria
Order: Vibrionales
Family: Vibrionaceae
Genus: Vibrio
Species: V. parahaemolyticus
TAXONOMY

4. Description
Vibrio parahaemolyticus
is a curved, rod-shaped, Gram-
negative, oxidase positive, aerobic
and does not form spores.
Like other members of the genus
Vibrio, this species is motile, with
a single, polar flagellum.

5. V. parahaemolyticus is a halophilic organism that
thrives in coastal, brackish waters of marine and
estuarine environments around the world including
the United States, South America, Asia, Australia, and
Europe.

7. PATHOGENESIS
Transmission
Vibrio parahaemolyticus is typically transmitted to human hosts
through the consumption of raw and undercooked shellfish
including clams, muscles, and oysters.
Reports of contaminated crab and finfish have also contributed to
incidences of infection in the past.
Annual increases in incidences worldwide are observed during
the spring and summer months when water temperature is
elevated and more favorable for the pathogen’s survival in its
estuarine environments.

8. Infectious dose and incubation period
In an experimental study, the World Health
Organization estimated the infectious dose to be
1,000,000 microorganisms. Clinical symptoms of
the infection will manifest within 2-48 hours of
ingestion, and will last anywhere from 2-8 days.

9. GROWTH/SURVIVAL
CHARACTERISTICS IN FOODS
 TEMPERATURE- The temperature reported for growth are min. and max. 5 deg. Cent.
and 44 deg. Cent. and optimum of 30-35 deg. Cent. It fails to grow at 4 deg. Cent.
 HEAT RESISTANCE- not a heat resistant organism and destroyed by cooking of >65
deg. Cent.
 pH- range for growth is 4.8-11 and optimum 7.6-8.6
 aW/SALT- Water activity of approximately 0.98, but can tolerate as low as 0.922.
V. parahaemolyticus is unable to grow in the absence of salt; its upper and
lower limits for growth are 8% and 0.5% NaCl respectively, but the optimum
concentration is 2-4%.

10. Virulence Factor
The key virulence factor secreted by V. parahaemolyticus is
termed thermostable direct hemolysin (TDH).
TDH is a pore-forming toxin, and causes an influx of ions into
certain cells, disrupting signal transduction and osmotic balance,
which results in cell death.
Consequently, fluid secretion causes the production of watery
diarrhea.

12. SYMPTOMS
skin lesions
Diarrhoea
vomiting
abdominal pain
Mild fever

13. Diagnosis
•Physicians should test for V. parahaemolyticus infection in
patients who produce diarrheal stool, particularly those who
have ingested shellfish in the past 24 hours.
• Stool samples should be cultured on TCBS agar in order to
accommodate for the very specific growth conditions.
• Samples from wound infections and blood may be
serotyped for toxigenic proteins to determine the presence
of the pathogen .

14. Vibrio strains grown on selective media – yellow colonies, Vibrio cholerae,
the causative agent of cholera, and green, Vibrio parahaemolyticus .

15. Treatment
Most mild and moderate clinical cases do not require the
use of antibiotics.
 The Centers for Disease Control and Prevention
emphasizes the fact that "antibiotics do not decrease the
severity of length of the illness".
In severe cases involving septicemia or prolonged
infection, antibiotics Tetracycline or Ciproflaxin may be
administered. Caution should be taken when administering
antibiotics.

16. Prevention
•Effective prevention methods for V. parahaemolyticus infections
include
Thoroughly cooking seafood before consumption,
Refrigerating raw seafood within 8 hours of marine acquisition, and
Avoiding open-wound contact (e.g. burns, cuts, and tattoos) with
warm saltwater .
•Ultimately, this will stimulate awareness and quick investigation in
order to isolate the source of contamination.

17. V. parahaemolyticus was first implicated as
causing a food-poisoning type outbreak
after the consumption of a fish product in
Japan in 1950.

18. Rectal biopsy tissue stained (pink) showing inflammation caused by V.
parahaemolyticus at the acute stage, day 2 (C) and after recovery, day 30 (D)

19. Hosts
Hosts of V. parahaemolyticus include:
Aquatic gastropod mollusk
(species of freshwater
and brackish water snail)
Litopenaeus shrimp
(suspected; possibly
causes necrotising
hepatopancreatitis)
Nerita albicilla,
(species of sea snail, a
marine gastropod mollusk)
Oysters

20. References:
• microbewiki.kenyon.edu
• en.wikipedia.org
• www.foodsafety.gov
• www.ncbi.nlm.nih.gov
• [Infectious Agents Surveillance Report: Vibrio parahaemolyticus,
Japan, 1996-1998. (Accessed July 24, 2013)

21. THANK YOU