1. WHO/HSE Tanzania February 01, 2017
Avian Influenza
An overview and an Update on Tanzania
WHO/HSE
Tanzania
February 01, 2017

2. Influenza viruses - Classification
Influenza viruses belong to the orthomyxovirus family, which has the genera: influenza A, B, and C virus, and Thogovirus
Have spherical or filamentous enveloped particles, that carry surface transmembrane glycoproteins haemagglutinin (H or HA) and neuraminidase (N or NA) glycoproteins used for subtyping.
Currently, there are 16 hemagglutinins (H1 to H16) and 9 neuraminidases (N1 to N9)

3. Influenza viruses Influenza A viruses: Influenza B viruses:
infect humans and many different animals.
Influenza B viruses:
only circulate among humans and cause seasonal epidemics.
Influenza C viruses:
can infect both humans and pigs but infections are generally mild and are rarely reported.
In humans:
A and B viruses are of epidemiological importance

4. A/goose/Guangdong/1/96 (H5N1)
Nomenclature
A/goose/Guangdong/1/96 (H5N1) 1 2 3 4 5 6
Antigen type (A or B)
Isolate host species (omitted if human in origin)
Geographical site
Isolate reference serial number,
Year of isolation,
Hemagglutinin (H or HA) and neuraminidase (N) variants in brackets 1 4 2 5 6 3

5. Influenza examples
Depending on the origin host, influenza A viruses can be classified as:
Influenza "bird flu" virus subtypes A(H5N1) and A(H9N2)
Swine influenza "swine flu" virus subtypes A(H1N1) and A(H3N2) or
Other types of animal influenza viruses

6. Types of Avian Influenza in domestic poultry
Low pathogenic avian influenza (LPAI)
mild or no clinical signs
low to moderate mortality
May easily go undetected
However, the low pathogenic H5 and H7 strains are capable of mutating under field conditions into highly pathogenic strains
Highly pathogenic avian influenza (HPAI)
sudden onset
severe clinical signs
high mortality (>95% in hours)
Rapid spread in poultry
First identified in Italy in 1878

7. Avian influenza
Disease caused by infection with avian (bird) influenza (flu) Type A viruses
Viruses occur naturally among wild aquatic birds (ducks, geese, and swans, gulls, terns, plovers, surfbirds, sandpipers, puffins) worldwide.
Can infect domestic poultry and other bird and animal species.

8. Avian influenza
Avian flu viruses do not normally infect humans or result in efficient transmission of viruses between people.
Influenza type A viruses are distinct from human influenza viruses and do not easily transmit between humans.
Human infections are primarily through direct contact with infected animals or contaminated environments.

9. Why get concerned?
Migratory birds can introduce LPAI H5 and H7 viruses to poultry flocks, which then mutate to HPAI.
Avian influenza viruses are readily transmitted from farm to farm by the movement of live birds.
Threat to global health: Unprecedented human exposure to a novel HA subtype, naïve populations
morbidity and mortality in humans
Easily transmissible from person to person
Social and economic impacts

10. Emergence of novel viruses: Mutation
Antigenic Drift
through small changes in the virus, continually over time
Results in new virus strains; unrecognized by antibodies to earlier influenza strains
Antigenic Shift
Sudden, major change;
Results in a new influenza virus that can infect humans and is unrecognized by antibodies

11. Emergence of novel viruses: Mutation and Reassortment 1
Avian virus
Human virus
2. Reassortment
Reassortant
Human- Avian virus

12. Emergence of novel viruses: Mutation and Reassortment 2
Avian virus
Human virus
2. Reassortment
Reassortant
Human- Avian virus

13. Avian Influenza virus in Uganda
16/01/ Director Animal Resources, Department of Livestock Health and Entomology
Report type
Immediate notification
Date of start of the event
02/01/2017
Date of confirmation of the event
14/01/2017
Report date
15/01/2017
Date submitted to OIE
16/01/2017
Reason for notification
First occurrence of a listed disease in the country
Causal agent
Highly pathogenic influenza A virus
Serotype H5
Source:

14. Avian Influenza virus in Uganda
Highly pathogenic avian influenza virus A(H5)
Districts: Kachanga, Bukibanga, Bukakata, Masaka
continuous deaths of wild ducks and birds along the shores and islands of Lake Victoria in Masaka and Wakiso districts.
In Masaka wild and domestic birds with high mortality
In Lutembe wetland white-winged terns dying
Threat to over thirty million domestic poultry in Uganda
Source:

15. Avian Influenza virus in Uganda
Report type
Follow-up report No. 1 (15/01/2017)
Date of start of the event
02/01/2017
Date of confirmation of the event
14/01/2017
Report date
27/01/2017
Date submitted to OIE
Reason for notification
First occurrence of a listed disease in the country
Causal agent
Highly pathogenic influenza A virus
Serotype
H5N8
Nature of diagnosis
Laboratory (advanced)
This event pertains to
a defined zone within the country
Related reports
Immediate notification (15/01/2017)  Follow-up report No. 1 (27/01/2017) 

16. Map of outbreak locations -Uganda
Source:

17. Assessment of risk associated with influenza A(H5N8) virus (WHO: 11/17/2016)
Influenza A(H5N8) virus first detected in domestic ducks in China in live poultry market
Avian influenza A(H5N8) viruses rapid spread via wild migratory birds in Asia and Europe, Africa
Although the likelihood of human infection with the A(H5N8) virus is low, if cannot be excluded, based on current and limited information to date.

18. HPAI During 2014, HPAI detected in wild birds and poultry in:
China, Germany, Italy, Japan, Netherlands, Republic of Korea, Russian Federation, and the United Kingdom of Great Britain and Northern Ireland. In late 2014: North America Canada, United States of America
2015:
Taiwan, China, Hungary and Sweden
2016, (in wild birds and/or domestic poultry):
countries in Europe and Asia including Austria, Croatia, Denmark, Germany, Hungary, India, Israel, Netherlands, Poland, Russian Federation and Switzerland
Many of these recent detections were associated with mortality in wild birds.
Source:

19. Human infections
To date, no human cases of infection with influenza A(H5N8) have been detected.
Human cases with related clade A(H5N6) viruses have been detected and reported in China.
Human infections with A(H5) viruses: rare and occur among those exposed to sick/dead infected birds (or their environments).

20. Avian Influenza A(H5N1)
Influenza H5N1 virus - causes a highly infectious, severe respiratory disease in birds (avian influenza)
Human cases of H5N1 avian influenza are rare; it is difficult to transmit the infection from person to person. (concern is of mutation, gene reassortment)
Infection through close contact with infected live or dead birds, or H5N1-contaminated environments
High mortality in humans (about 60%)

21. Avian Influenza A(H5) in Tanzania
No confirmed reports of deaths of wild ducks and birds
Meetings under the One Health Unit in the Prime Minister’s Office (MALF, Health, Wildlife, Partners)
Costed plan to visit areas around Lake Victoria (Kagera, Mwanza, Geita, Mara)
Need to revise preparedness and response plan
Review of stocks: PPEs, oseltamvir
Prepositioning in WHO regional sites (IST)

22. Influenza surveillance in Tanzania
Alert letters sent to administrative secretaries in all regions.
Capacity: 7 sentinel surveillance for influenza.
influenza-like illness (ILI), severe acute respiratory illness (SARI)
Gaps in surveillance capacity - HR, lab supplies, community participation and engagement

23. WHO response to avian influenza?
WHO collaborates with global health partners and agencies, including the World Organisation for Animal Health (OIE), and the Food and Agriculture Organization of the United Nations (FAO), to control and prevent the spread of animal diseases (Zoonosis).

24. Thank you