# Presentation: 211664

## Clinician Update on Avian Influenza

**Scott F. Dowell, MD, MPH**

## Outline

- Pandemic influenza versus seasonal flu
- Clinical features of influenza A (H5N1)
- Early recognition and containment of AI
- Resources for clinicians

## Recognizing Avian Influenza

## Pandemic Influenza

**Notes:**
An overwhelmed ambulance service

## US Infectious Disease Mortality:The Impact of Influenza and AIDS

- Armstrong. JAMA 1999;281:61

## 1918 Hemagglutinin Causes Severe Lung Damage

- M88

- M88/Hsp

- Kobasa et al. Nature 2004;431:703

## Neuraminidase Sets Up Bacterial Pneumonia

- Peltola et al. JID 2005;192:249

## Slide 8

## Avian Influenza in Asia(22 August, 2005)

## Human H5N1 Most Common in Children

| Age | Sex | Onset | Exposure | Outcome |
| --- | --- | --- | --- | --- |
|   7 | M |   3 Jan | Dead poultry at neighbors | Died |
|   6 | M |   6 Jan | Dead poultry at neighbors | Died |
|   6 | M |   7 Jan | Sick poultry at neighbors | Died |
| 58 | F | 19 Jan | Sick poultry in backyard | Died |
| 27 | F | 20 Jan | Purchased, cooked chicken from affected area | Recovered |
|   4 | M | 21 Jan | Sick/dead fighting cocks, poultry in backyard | Died |
|   6 | M | 24 Jan | Dead poultry in backyard | Died |
|   2 | M | 25 Jan | Sick poultry in backyard | Recovered |
| 13 | M | 26 Jan | Sick poultry in backyard | Died |
| 47 | F |   3 Feb | Sick/dead fighting cocks in backyard | Recovered |
| 29 | M | 13 Feb | Sick/dead fighting cocks, chicken in backyard | Recovered |
| 39 | F |   1 Mar | Dead fighting cock at neighbors | Died |
| 18 | M | 31 Aug | Sick/dead fighting cock in backyard | Died |

- Chotpitayasunondh. MMWR 2004;53:100

## Thai Children at Risk for H5N1 Infection

| Knowledge, attitudes, and practices* | Before | After | p-value |
| --- | --- | --- | --- |
| Thought it was safe to touch sick or dead poultry with bare hands  |  78 (40) |  27 (14) | <0.01  |
| Thought it was safe for children to touch sick or dead poultry with bare hands |  45 (23) |     9 (5) | <0.01  |
| Children in your household touched sick or dead poultry with bare hands |   12 (6) |     7 (4) |   0.4 |
| Took dead chicken or poultry from your yard and prepared it to eat |   24 (12) |   17 (9) |   0.3 |

- * Before and after a public education campaign
- Olsen et al. EID 2005;11:

- Chotpitayasunondh. MMWR 2004;53:100

## Influenza A (H5N1) Pneumonia

- Hien. NEJM 2004;350:1179

## Lymphopenia Predicts Mortality

- Chotpitayasunondh et al. EID 2005;11:201

## Early Oseltamivir Associated with Survival

- Chotpitayasunondh et al. EID 2005;11:201

## H5 in 2004 is More Virulent and Requires More Oseltamivir

- Mouse model of lethal H5 infection
- ’04 virus more lethal than ’97 virus
- Oseltamivir was protective
- Higher dosages needed
- 8-day regimen better than 5-day

- Yen et al. JID 2005;192:665

## Clinical Features of Avian Influenza

- Persistent fever, lymphopenia
- Severe pneumonia or ARDS
- unusual presentations possible
- Exposure to sick poultry
- Exposure to affected areas or persons
- Clustering may be an emergency

## Investigating Person-to-Person Spread

## Timeline of Exposures and Illness

- Ungchusak. NEJM 2005:352;333

## Getting the Virus

- Urgent effort to get specimens to WHO network
- Index patient dead, cremated
- Mother’s body embalmed
- Lung and other tissues tested by RT-PCR and IHC
- Aunt survived
- NP and OP swabs tested by cell culture, RT-PCR
- Acute and convalescent serum (neutralization, ELISA)

## Containing Pandemic Influenza With Antiviral Agents

- Theoretical models using Thailand data
- Contacts of suspected cases take antiviral agents
- Pandemic contained if Ro low
- Prophylaxis with quarantine more effective
- Critical is speed of detecting cases and response

- Longini IM et al. Science 2005
- Ferguson et al. Nature 2005

## No. of  Cases

- Day of illness

- Baseline

- 8-week 80% TAP

- +2

- +15

- Outbreak
-  Recognized
-  ~Day 68

- _Typical “Large” Outbreaks_
- _(Hong Kong Calibration)_

- +10

## An Influenza Pandemic and the Clinician

- Know clinical and epidemiological features
- Teach your colleagues
- Have a pandemic plan
- Have antivirals and protective equipment
- Be prepared to lead
- Confirm the diagnosis
- Get the virus
- Get a lot of help, fast

## Resources for Clinicians

- _[www.cdc.gov](http://www.cdc.gov/)_
- U.S. public health guidelines
- _[www.pandemicflu.gov](http://www.pandemicflu.gov/)_
- U.S. pandemic plan
- _[www.who.int](http://www.who.int/)_
- Global updates and official case reports
- More coming