Department of Community Medicine » Update 44 ARI

Swine-origin Influenza A (H1N1) Virus Infection

Fri, 04 Sep 2009 13:27:52 +0000

IDSP Tvm // Information release

Swine-origin Influenza A (H1N1) Virus Infection

Transmission

Transmission of novel influenza A (H1N1) is being studied as part of the ongoing outbreak investigation, but limited data available indicate that this virus is transmitted in ways similar to other influenza viruses. Seasonal human influenza viruses are thought to spread from person to person primarily through large-particle respiratory droplet transmission (e.g., when an infected person coughs or sneezes near a susceptible person). Transmission via large-particle droplets requires close contact between source and recipient persons because droplets do not remain suspended in the air and generally travel only a short distance (< 6 feet). Contact with contaminated surfaces is another possible source of transmission and transmission via droplet nuclei (also called “airborne” transmission). Because data on the transmission of novel H1N1 viruses are limited, the potential for ocular, conjunctival, or gastrointestinal infection is unknown. Since this is a novel influenza A virus in humans, transmission from infected persons to close contacts might be common. All respiratory secretions and bodily fluids (diarrheal stool) of novel influenza A (H1N1) cases should be considered potentially infectious.

Incubation period

The estimated incubation period is unknown and could range from 1-7 days, and more likely 1-4 days.

Persons with confirmed novel influenza A (H1N1) virus infection

Case Definitions

Acute febrile respiratory illness is defined as a measured temperature 100 degrees Fahrenheit and recent onset of at least one of the following: rhinorrhea or nasal congestion, sore throat, or cough.

A confirmed case of S-OIV infection is defined as a person with an acute febrile respiratory illness with laboratory confirmed S-OIV infection at CDC by one or more of the following tests:

real-time RT-PCR
viral culture

A probable case of S-OIV infection is defined as a person with an acute febrile respiratory illness who is positive for influenza A, but negative for H1 and H3 by influenza RT-PCR

A suspected case of S-OIV infection is defined as a person with acute febrile respiratory illness with onset

within 7 days of close contact with a person who is a confirmed case of S-OIV infection, or
within 7 days of travel to community either within the United States or internationally where there are one or more confirmed cases of S-OIV infection, or
resides in a community where there are one or more confirmed cases of S-OIV infection. .

Clinical findings

Patients with uncomplicated disease due to confirmed novel influenza A (H1N1) virus infection have experienced fever, chills, headache, upper respiratory tract symptoms (cough, sore throat, rhinorrhea, shortness of breath), myalgias, arthralgias, fatigue, vomiting, or diarrhea.

Influenza

Fri, 04 Sep 2009 12:06:24 +0000

INFLUENZA (Powerpoint)

Pneumonia

Fri, 04 Sep 2009 11:55:43 +0000

Types of Pneumonia

Community Acquired
Hospital Acquired
Immunocompromised / Structurally Abnormal

Community Acquired Pneumonia

Clinical Features

Fever, rigor, chills, headache, malaise, cough, chest pain, dysponea, confusion
Pyrexia, tachycardia, tachypnoea, cyanosis
Pleural rub, bronchial breathing, impaired resonance, increased increased VF and VR creps
Investigations
CBC
Radiological
Bacteriological
Blood gas

S. PNEUMONIAE PNEUMONIA

Young to middle age
Acute onset
High fever, toxic, rigor
High TC, Europhilia,, toxic granules
X-ray : labar non homogr\enous opacity
Gram +ve diplococci in sputum

CHLAMYDIA PNEUMONIA
Young and middle age
Sporadic or epidemic
Onset mild may be self limiting
Associated URI
Small segmental infiltates
Normal WBC count + raised SGPT
+ve serology

MYCOPLASMA PNEUMONIA

Children and young
Insidious onset
More systemic features
Few respiratory findings
Assoc:EN, myo/pericarditis, meningoencephalitieis, heamolysis, rach
Patchy/lobar consolidation + / -hilar lymph node

UNCOMMON ORGANISMS

H. Influeza: pre-existing lung disease, bronchopneumonia in X-ray
S.Aureus: often seen in assoc: with viral pneumonia / Chronic debilitating illness or spread from abscess / osteomyelities and lobar/ segmental opacity, abscess, pneumatocoele
K.pneumoniae: very young and old age, marked systemic features, upper lobe predilication early abscess formation

VIRAL PNEUMONIAS

Caused by influenza – A / B
Chicken-pox
Avaian influenza

BAD PROGNOSTIC INDICATORS

Age> 60
H.R > 140
B.p – systolic <90 and diastolic <60
Altered mental status
More than one lobe affection
Coexistant disease
PO 2 < 60
WBC count >20000 0r <4000
Elevation of B. urea

MANAGEMENT

General measures
Antibiotics
Oxygen
Treatment of complications

GENERAL MEASURES

Rest
Antipyretics
Analgesics
Physiotherapy

ANTIBIOTICS

Started as early as possible
Sputum and blood culture
Should cover the most probable organism
Pattern in alocality
Resistance probability
Optimum dose

UNCOMPLICATED MILD CAP

Macrolide - Azithromycin , Clarithromycin

Fluroquinolones - gatifloxacin, levfloxacin, moxifloxacin

Doxcyclin

SEVERE CAP

Clarithromycin 500 mg I.V. Q12H or Azithromucin 500 mg I.V> OD
or Levofloxacin /gatifloxacin . I.V + Co-amoxiclav 1-2 gm I.V Q8H or ceftriaxone 1-2 gm Q12H + flucloxacillin 2 gm I.V Q6H

OXYGEN

In all cases with hypoxia
Ventillation in severe cases