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Seasonal influenza Avian Influenza Swine flu Acute highly infectious viral disease characterized by fever, general & catarrhal manifestations. Infectious viral disease of birds. Some (AI) viruses can cause infections (clinical or subclinical) in humans. Acute infection caused by Type A influenza viruses (H1N1 subtype).
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Viral Droplet InfectionsDr. Abd El hamied
Mohamed Abd El hamied
Lecturer of Occupational Health & Industrial Medicine
Viral Droplet Infections Seasonal
Influenza Avian Influenza Swine Influenza
Seasonal influenza
Avian Influenza
Swine flu
Acute highly infectious viral disease characterized by fever, general & catarrhal manifestations.
Infectious viral disease of birds. Some (AI) viruses can cause infections (clinical or subclinical) in humans.
Acute infection caused by Type A influenza viruses (H1N1 subtype).
Public health significance:
Seasonal influenzaOccurs as sporadic cases, outbreaks, epidemics &
pandemics.
In the last century, there are 3 pandemics. During epidemics, clinical attack rates range from 10-20% in general population to >50% in closed population.
Influenza epidemics evolve rapidly, spread widely with serious complications & death especially in elderly & patients with chronic debilitated diseases.
Avian Influenza1st direct bird to human spread of H5NI occurred
in Hong Kong in 1997.
Re-emergence in December 2003 & spread from Asia to Europe & Africa (pandemic), resulting in millions of poultry infections, hundreds of human cases & many human deaths.
In Egypt, 1st direct bird to human spread of H5N1 occurred in 2006 & total cases in 2009 were 85 with a total deaths of 27 (CFR is 31.7%)
Globally general CFR reached ► 50%.
Swine flu In April 2009 WHO declared a "public health ►
emergency of international concern" when 1st 2 cases of H1N1 virus were reported in US, followed by hundreds of cases in Mexico.
In April 2010,CFR was at least 17.700 deaths worldwide.
Risk factors : extremities of agepregnant females individuals with syst emic diseases.
In Egypt in 2009 → 808 cases were confirmed with 2 deaths (CFR around 0.2%).
In Aug-2010, WHO declared that swine flu pandemic officially over.
Causative agent
Seasonal influenzaType A: epidemics & pandemics. Type B: regional epidemicsType C: sporadic cases & localized outbreaks.
☻Has 2 antigens projecting from its surface:
Haemagglutinin (HA) Neuraminidase (NA)16 known subtypes 9 known subtypesSite of attachment to host cells
Helps releasing newly formed viruses from host cells
WHO nomenclature for influenza
Strain type (A, B or C) / Geographical origin / Laboratory reference number/ year of occurrence / (description of H&N antigens).
For example; A/ Mississippi/1/85/ (H3N2)
Antigenic drift Antigenic shiftModification of HA & NA
viral proteins → a new variant of A subtype with antibodies against previous strains are not able to neutralize this new variant → regional outbreaks & annual epidemics
Replacement of viral proteins, mostly due to genetic recombination of human & animal influenza viruses → a completely new A subtype → pandemic.
Since 1918, the only 3 influenza A sub-types
known to cause human disease are: H1N1, H2N2
& H3N2. Other subtypes such as H5N1 are rare.
Since isolation of influenza virus in 1933,
antigenic shifts occurred 3 times: in 1957, 1968 &
1977 (causing pandemic every time).• •
No cross immunity between different antigenic strains.
Avian Influenza Current pandemic is caused by subtype H5N1.
Swine flu Type A influenza viruses (H1N1 subtype).
Resistance: Killed by heat& oxidizing
agents.
Killed at 70C,by
alcohol, vinegar &
disinfectants.
Reservoir of infection: Human cases (typical or
atypical)+ swine + avian
Birds (wild &
domestic) + pigs
Human cases + pigs
Exit: Nasopharyngeal secretions
Nasopharyngeal
discharges,
lacrimal
discharges,
faeces & blood.
Period of communicability: 3-5 days from clinical
onset in adult. 7 days in young
children.
1 day before symptoms
up to 7 or more days
after becoming sick.
Resistance: Killed by heat& oxidizing
agents.
Survives in low
temperature & water.
Killed at 70C,by
alcohol, vinegar &
disinfectants.
Reservoir of infection: Human cases (typical or
atypical)+ swine + avian
Birds (wild &
domestic) + pigs
Human cases + pigs
Exit: Nasopharyngeal secretions
Nasopharyngeal
discharges,
lacrimal
discharges,
faeces & blood.
Period of infectivity: 3-5 days from clinical
onset in adult. 7 days in young
children.
1 day before up to 7
days after becoming
sick.
Modes of transmission
1. Direct droplet.2. Nasal inoculation after hand contamination with
virus. 3.Freshly contaminated articles with
nasopharyngeal discharges.
4. Air borne: (droplet nuclei & infected dust).
Seasonal influenza
Avian Influenza1. ANIMAL TO ANIMAL INFECTION: direct
contact of susceptible animal to secretions (saliva, nasopharyngeal, feces or blood) of infected animals. Many different animals are infected including ducks, chicken, pigs, whales, horses & seals.
2. Animal to human infection: direct contact of humans with infected poultry, its discharges & feces.
Antigenic shift & the danger of person to person transmission:
If a pig is infected with both human influenza A
virus & AI virus in the same time, mixing genes
(Re-assortment) occur →a new virus → able to
infect humans & spread from person to person
resulting in an influenza pandemic.
IP: 1-3 days International 7 days.
Susceptibility:
1. Age: all ages are susceptible. 2.Immunity: Type specific & Transient immunity. Recurrent attacks due to multiple
strains, genetic mutation & no cross immunity between different strains.
3.Environment:Cold, over-crowdness & ill ventilation.
Clinical Picture: Sub-clinical, mild, moderate or severe form. Acute fever, headache, myalgia, prostration, back pain, sore throat, rhinorrhea & cough. Self limited disease (recovery within 2-4 days).
High fever + influenza-like symptoms.
Diarrhea, vomiting, abdominal pain & bleeding from nose and gums.
As seasonal human flu.
Some people have reported diarrhea + vomiting.
Complications:1. 2ry bacterial infection e.g.
bronchitis, 2. Children with salicylate therapy ►Reye disease (CNS & liver).
Diagnosis ofSeasonal Influenza
Laboratory Diagnosis
1.Direct identification of viral antigen in nasopharyngeal cells by FA test or ELISA.
2. A rising titre of specific serum antibodies.
Diagnosis ofSwine Flu
Case classification:
•Possible case: clinical +epidemiological criteria.
•Probable case: clinical + epidemiological criteria + positive influenza rapid testing.
•Confirmed case: laboratory confirmation
Clinical criteria: one of the following:
1. Fever >38°C OR history of fever AND flu-like illness (≥2 of the following symptoms: cough, headache, rhinorrhea or vomiting/diarrhea).
2. Severe/life-threatening illness .
• Epidemiological criteria:
• At least one of the following in a person during the 7 days before onset of illness:
1. Close contact with a confirmed or probable case of swine flu A (H1 N1) virus infection.
2. Traveled to a geographical area known to have confirmed cases of swine influenza A/H1 N1
Prevention & Control
Prevention: General: Specific:
A.Active immunization:
1. Inactivated trivalent vaccine:
Nature:Killed containing 2 subtypes of A virus (H1N1 & H3N2), B strain (currently circulating strains present in the locality).
☻Efficacy: 80%
reduce complications by
60% & death by 80 %.
☻Dose: 2 doses 0.5 ml I.M. for
children not immunized
before. Single dose if immunized
before. Vaccine should be given
each year before season
of expected influenza.
☻Indications:1. Old aged persons above
65 years
2. Cases with chronic
debilitating diseases.
3. HCWs.
4. Immunosuppressed
children.
2. Live attenuated intranasal vaccine:
Formed of 2 subtypes
A&B Heat sensitive
vaccine. Given 0.5 ml by
intranasal spraying. Produces local &
systemic immunity.B.
Chemoprophylaxis: for
influenza A not B Admantadine HCL: 200
mg orally for 10 days for
adults & 100 mg for
children. Side effects: fever & CNS
(5-10 % of cases). Indications: high risk
groups as elderly,
children & chronic
disease. Contraindicated in patient
with psychological or
neurological disorders.
Prevention + Control:
1. General measures of prevention for droplet & contact infections.
2. Measures for patients with AI:
a. Isolation: in fever hospital with standard precautions.
Respiratory
precautions, hand
hygiene, gloves,
gowns, eye
protection,
disposable blood
pressure cuffs,
thermometers….etc
.
3.Measures for HCWs: Standard
precautions,
surveillance,
vaccination to
reduce risk of co-
infection with
human & avian
strain.
4. Precautions for food preparation especially poultry:
Raw poultry
should be handled
hygienically. Cook all poultry&
poultry products to
reach a high
temperature
above 70. Eggs should not
be consumed raw
or partially
cooked. Washing of hands
with soap + water
after handling
frozen or raw
chicken or eggs.
5. LAV given to
poultry.
6. Tamiflu: anti viral
drug of choice.
Prevention: A. General A. General
1. HE of public: Wash your hands.
Avoid touching your
eyes, nose or mouth
Avoid touching
surfaces
contaminated with
virus.
Healthy habits during
cough & sneezing.
Sanitary environment.Measures for swine: Culling: killing large
numbers of infected &
potentially infected
animals. Quarantine: putting
infected farms in
quarantine. Cook pork
thoroughly. Avoid live animal
markets, poultry and
pig farms in infected
countries.
B. Specific prevention
A recently developed
vaccine given for at
risk groups e.g.
pilgrims.
Prevention: General: Specific:
A.Active immunization:
1. Inactivated trivalent vaccine:
☻Nature:Killed
2 subtypes of A & B strains.
☻Efficacy: 80%
reduce complications by
60% & death by 80 %.
☻Dose: 2 doses 0.5 ml I.M. for
children not immunized
before. Single dose if immunized
before.
☻Indications:1. Old aged persons > 65
years
2. Chronic debilitating
diseases.
3. HCWs.
4. Immunosuppressed.
2. Live attenuated intranasal vaccine:
Formed of 2 subtypes
A&B Heat sensitive
vaccine. Given 0.5 ml by
intranasal spraying. Produces local &
systemic immunity.B.
Chemoprophylaxis: for
influenza A not B Admantadine HCL: 200
mg orally for 10 days for
adults & 100 mg for
children. Side effects: fever & CNS
(5-10 % of cases). Indications: high risk
groups as elderly,
children & chronic
disease. Contraindicated in patient
with psychological or
neurological disorders.
Prevention + Control:
1. General measures of prevention for droplet & contact infections.
2. Isolation precautions for patients with avian flu:
b. Nursing precautions: hand hygiene, gloves, gowns, eye protection, disposable blood pressure cuffs, thermometers, etc.c. Tamiflu: anti viral drug of choice.
3. Measures for HCWs: Standard
precautions,
surveillance,
vaccination to ↓ risk of
co-infection with
human & avian strain.
4. Precautions for food preparation especially poultry:
Raw poultry
should be handled
hygienically. Cook all poultry&
poultry products to
reach a high
temperature
above 70. Eggs should not
be consumed raw
or partially
cooked. Washing of hands
with soap + water
after handling
frozen or raw
chicken or eggs.
5. LAV given to
poultry.
6. Tamiflu: anti viral
drug of choice.
Prevention: A. General Prevention
1. HE of public: Wash your hands. Avoid touching your
eyes, nose or mouth.Avoid touching
surfaces
contaminated with
virus.Avoid contact with
sick people.Healthy habits during
cough & sneezing.
2. Measures for swine: Culling: killing large
numbers of infected &
potentially infected
animals.
Quarantine: putting
infected farms in
quarantine.
Cook pork
thoroughly.
Avoid live animal
markets.
B. Specific prevention
A recently developed
vaccine given for at
risk groups e.g.
pilgrims.
Prevention: General: Specific:
A.Active immunization:
1. Inactivated trivalent vaccine:
☻Nature:Killed
2 subtypes of A & B strains.
☻Efficacy: 80%
reduce complications by
60% & death by 80 %.
☻Dose: 2 doses 0.5 ml I.M. for
children not immunized
before. Single dose if immunized
before.
☻Indications:1. Old aged persons above
65 years
2. Chronic debilitating
diseases.
3. HCWs.
4. Immunosuppressed.
2. LA intranasal vaccine: 2 subtypes A&B Heat sensitive vaccine. 0.5 ml intranasal. Produces local & systemic
immunity.
Indication: only for healthy
people aged 5–49 ys.
B. Chemoprophylaxis: 1. Admantadine HCL: adults 200 mg (children100 mg) orally for 10 days.
2. Remantadine HCL: for influenza A but not B.
Side effects: fever & CNS
(5-10 % of cases). Indications: high risk
groups as elderly,
children & chronic
disease. Contraindicated in patient
with psychological or
neurological disorders.
Prevention + Control:
1. General measures of prevention for droplet & contact infections.
2. Isolation precautions for patients with avian flu:
Respiratory,hand,
gloves, gowns, eye
protection,
disposable cuffs,
thermometers….etc
3.Measures for HCWs: Standard
precautions,
surveillance,
vaccination to
reduce risk of co-
infection with
human & avian
strain.
4. Measures during food preparation especially poultry: a. Hygienic Handling of raw poultry. b. Hand washing with soap & water after handling frozen or raw chicken or eggs. c. Cook all poultry & products to a high temperature > 70.
Washing of hands
with soap + water
after handling
frozen or raw
chicken or eggs.
5. LAV given to
poultry.
6. Tamiflu: anti viral
drug of choice.
Prevention: A. General
1. HE of public: Wash your hands. Avoid touching your
eyes, nose or mouth.Avoid touching
surfaces
contaminated with
virus.Avoid contact with
sick people.Healthy habits during
cough & sneezing.
2. Sanitary environment.
3. Measures for swine: Culling: killing large
numbers of infected &
potentially infected
animals. Quarantine: putting
infected farms in
quarantine. Cook pork
thoroughly. Avoid live animal
markets.
B. Specific prevention
Vaccination of at risk groups e.g. pilgrims.
Prevention: General: Specific:
A.Active immunization:
1. Inactivated trivalent vaccine:
☻Nature:Killed
2 subtypes of A & B strains.
☻Efficacy: 80%
reduce complications by
60% & death by 80 %.
☻Dose: 2 doses 0.5 ml I.M. for
children not immunized
before. Single dose if immunized
before.
☻Indications:1. Old aged persons above
65 years
2. Chronic debilitating
diseases.
3. HCWs.
4. Immunosuppressed.
2. LA intranasal vaccine: 2 subtypes A&B Heat sensitive
vaccine. 0.5 ml intranasal. Produces local &
systemic immunity.B.
Chemoprophylaxis:
For influenza A not B Admantadine HCL: 200
mg orally for 10 days for
adults & 100 mg for
children.
Side effects: fever & CNS (5-10 % of cases).
Contraindicated in patient with psychological or
neurological disorders.
Prevention + Control:
1. General measures of prevention for droplet & contact infections.
2. Isolation precautions for patients with avian flu:
Respiratory,hand,
gloves, gowns, eye
protection,
disposable cuffs,
thermometers….etc
3.Measures for HCWs: Standard
precautions,
surveillance,
vaccination to
reduce risk of co-
infection with
human & avian
strain.
4. Precautions for food preparation especially poultry:
Raw poultry
should be handled
hygienically. Cook all poultry&
poultry products to
reach a high
temperature
above 70. Eggs should not
be consumed raw
or partially
cooked.
d. Eggs should not be consumed raw or partially cooked.
5. LAV given to poultry.
Prevention: A. General
1. HE of public: Wash your hands. Avoid touching your
eyes, nose or mouth.Avoid touching
surfaces
contaminated with
virus.Avoid contact with
sick people.Healthy habits during
cough & sneezing.
2. Sanitary environment.
3. Measures for swine: Culling: killing large
numbers of infected &
potentially infected
animals. Quarantine: putting
infected farms in
quarantine. Cook pork
thoroughly. Avoid live animal
markets.
B. Specific prevention
A recently developed
vaccine given for at
risk groups e.g.
pilgrims.
Control ofSeasonal Flu
I. Case: Treatment: Antibiotics + Antiviral
(Amantadine or Remantadine within 48 h of onset for 3-5 days).
II. Contacts:Surveillance for IP.
Chemoprophylaxis.
III. Epidemic measures:1. HE of the public, particularly high risk groups.
2. Immunization for high risk groups.
3. Surveillance of the community.
4. Adequate supplies of antiviral drugs & vaccination.
Control ofSwine Flu
I. Case: Notification to WHO. Treatment: Tamiflu II. Contacts: Surveillance for maximum IP. Chemoprophylaxis.
III. Epidemic measures:1. Locally organized immunization programs for high risk groups.2. Surveillance.3. HE through media: about mode of transmission + prevention.
MOH plan for flu pandemic, 20071. Database of all available health care settings.
2. ↑ number & quality of Labs for diagnosis of H1 N1virus.
3. HE of individuals, HCWs about signs , symptoms & prevention.
4. Vaccination of HCWs with seasonal flu vaccine.
5. Provision of a strategic store of Antiviral drugs.
6. Provision of a strategic store of PPE e.g. masks.
7. Quarantine measures & sentinel surveillance e.g. at airports & fever hospitals.
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