Viral food born infections
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Transcript of Viral food born infections
Dr. Dalia El-ShafeiLecturer, Community Medicine
Department, Zagazig University
Food born infections
Viral• Poliomyelitis• Hepatitis A&E
• MCD
Bacterial• Typhoid &
paratyphoid• Brucellosis• Diarrheal diseases:• Food poisoning• Dysentery• Diarrhea diseases in
children• Cholera
Parasitic• Ascariasis• Entrobiasis• Amoebic dysentery• Heterophiasis• Fascioliasis• Hydatid cyst• Giardiasis• Toxoplasmosis
Mode of transmission:Fecal oral infection: a) Food-borne infection (ingestion infection). Contaminated food: vehicles are milk and any food that may be contaminated by handling, flies, water, or dust, and sewage-polluted water.b) Hand-to-mouth infection
Symptoms FHMA Nausea Abdominal pain Vomiting Diarrhea Gastroenteritis Fatigue
PreventionPrimary
Environment sanitation
Health promotionInternational
measures
SecondaryI. Measures for
case: Case f &
notification Isolation &
disinfection Treatment &
release2. Measures for
cont: Surveillance Supervision Segregation Isolation immunization
TertiaryPrevent complications & care of handicapped
1- General measures
A) General Sanitation of Environment:Safe water supply, Sanitary wastes disposal (refuse & sewage), Insect control (flies & cockroaches).Food sanitation includes control of food
handlersB)Health education :proper clean habits (including clean hands)
2- ControlI. Control of Cases:
Case-finding: needs efficient medical care (clinical & laboratory services
Notification to the LHO.Isolation: allowed at home when sanitary requirements are fulfilled, otherwise must be
at fever hospital.Disinfection: - concurrent: excreta (1% crude
phenol), articles and fomites.- terminal for objects, and cleaning of the room.Treatment: general and specific chemotherapy.
Rehabilitation Release
Viral food born DiseasesPolio Hepatitis
AHepatitis E
IP 7- 14 d 15- 50 d 21- 42 dMode of transmis
sion
- Faeco-oral- Food-borne- Oral-oral (droplet)
faeco-oralParenteral
y (viraemia)
Contaminated water or
food supplies
Reservoir - Cases- Carriers (contact,
incubatory, convalescent)
-cases-Incubatory C
Infectivity
From IP to convalescence
Last week of IP till Jaundice
Agent - Polio virus Picorna virus
Viral food born Diseases
Polio Hepatitis A Hepatitis E
C/P - Inapparent 90%- Minor (Abortive)
9%- Major (CNS) 1%
-Inapparent (influenza-like)-Classical: pre-icteric,
icteric, post-icteric- Fulminate: fatal
Diagnosis
-Lab: throat wash & stools exam- Serological:
rising Ab
- Lab: stools exam- Serological: IGM, liver
enz.
Specific prevent
ion
- Vaccine - Seroprophylaxis
- Vaccine
Classical C/PPre-
icteric
•FHMA, myalgia, arthralgia•GE, tender liver, dark urine
Icteric •Jaundice (sclera)
•Enlarged tender liver
Post-icteric
•Convalescence
Prevention Active
immunization Inactivated
vaccine1 ml IM(deltoid)2 doses, 4 weeks
apart
1 -At risk: CLD, travelers, lab.
2 -Children
Sero-prophylax
isHuman Ig
Before or few days after exp
1 -Contacts (within 2 wks)
2 -At risk: travelers (before or within 2 wks)
UVR
&UVR
NO CROSS IMMUNITY
Most frequentEpidemic
I WildEndemic
II Oct 1999Sporadic
III
• Reservoir• Cases: all clinical forms• Carriers: all types (incubatory. Convalescent,
healthy & contact who are temporary carrier .
In endemic area health carrier are most frequent due to polluted environment.
• Period of Infectivity• Contact & healthy carriers: about 2weeks.• Case: From IP to convalescence(temporary)
Polio
In apparent (90%)
No clinical manifestations
Acquired immunity & carrier state
Manifest (10%)
Abortive (minor illness) 9%
CNS (major illness) 1%
Non-paralytic (FHMA +
Meningism)
Paralytic (spinal, bulbar, bulbo-spinal)
Case-fatality:2-10%
Mout
h &t
hroa
t su
rger
y
Pregnancy &
corticoster
oids
Excessive muscle activity & fatigue
Active
immunizati
on
Diagnosis
• Throat washing or stools• Serological (neutralizing Ab): rising titer
Specific prevention• Passive immunization (Sero-
prophylaxis): non-practical
Normal human Ig (0.3 ml/kg BW)Exposed susceptible (pre exposure – rapidly
post exposure)
• Active immunization:Sabin & Salk
Sabin Polio vaccine• Oral, live attenuated trivalent vaccine made of the three types, of polioviruses.• 2, 4 and 6 months of age • 3 drops orally on the tongue.• Recently a zero dose is giving after birth as additional dose.• Booster Immunization: a booster dose is given at 9 months, 18-24 months, and school age.
Sabin Polio vaccine action• live attenuated viruses of the vaccine
invade and multiply in the intestinal cells, stimulating: humoral and local cellular immunity
• Humoral immunity: by neutralizing antibodies in serum. It protects the CNS Against invasion by the poliovirus.
• Cellular immunity: local tissue immunity in the intestinal mucosa so prevents establishment of infection in the intestine, and so prevent a carrier.
Sabin Polio vaccine advantages
1. Gives humoral and tissue immunity 2. attenuated viruses are excreted in
stools, to disseminate infection in the community
3. easily administrated 4. used in mass immunization.
5. inexpensive.6. Protective value up to 95%,
7. life long immunity.
• Cold chain: regenerated below 4 C
• Contraindications:1- Pregnancy 2- Corticosteroids 3-
Immune-deficiency
• Complications:Paralysis: very rarely (1/5 million)
Salk Polio vaccine
• Trivalent vaccine, inactivated (formalin).
• Used in non-endemic areas and together with Sabin vaccine in endemic area.
• 4 doses, 1.0 ml each, IM, starting at 4 months of age.
• 1st 3 doses 6-8 weeks apart, 4th dose 7 months later.
• Booster dose : at school age, and whenever an epidemic or outbreak threatens.
• Action: Salk vaccine gives humoral immunity. no cellular immunity
• Protective Value: prevents < 90 % of paralytic cases, and lowers severity of paralytic effect in the affected.
• Salk is given in Egypt as quadruple Salk DPT, IM, 2 doses at 4 &6 months
Control
Cases FNIDTR
Contacts
Enlistment
Case-finding (2wks)Booster v. or sero-
prophylaxis
Epidemics
Mass oral v.
Epid. studyAvoid
predisposing factors
MOH polio eradication•Sabin (1968):1ry
& booster•Salk
Immunization
•Motivation •Periodic
campaigns•Surveillance
(1990)
Satisfactory
coverage rate
Case studyAn adult male 30 years old is complaining
from fever, malaise, nausea, vomiting, abdominal pain and dark urine.
a) What are the other signs you have to look for in this case?
b) What is the most probable diagnosis?c) How can you confirm this diagnosis?d) What is the proper management of this
case? What is the expected prognosis?e) What are the measures you should do
for contacts?
The other signs• Jaundice .• Enlarged tender liver • palpable spleen.
The most probable diagnosis
•Hepatitis A
Confirm this diagnosis
•detecting virus in stools• serological tests for IGM in acute cases • elevated liver enzymes (not specific)
Proper management of this case
• Finding: • Notification: to local health
authorities.• Isolation: • Disinfection: • Treatment• Release
Measures for contacts•Enlistment • Immunization: Active and passive immunization within 2 weeks of exposure.•Examination: for early case finding•Surveillance: for 6 weeks
Bovine Spongiform Encephalopathy (BSE)
Mad Cow Disease (MCD)
Cretuzefeld Jacob
Disease (CJD)