WHOHSE Tanzania February 01 2017 An overview and an Update on Tanzania Influenza viruses Classification Influenza viruses belong to the orthomyxovirus family which has the genera ID: 558544
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Slide1
Avian Influenza
WHO/HSE
TanzaniaFebruary 01, 2017
An overview and an Update on TanzaniaSlide2
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
)Slide3
Influenza virusesInfluenza A 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
importanceSlide4
Nomenclature 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
A/goose/Guangdong/1/96 (H5N1)
1
2
3
4
6
5
1
2
3
4
6
5Slide5
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 virusesSlide6
Types of Avian Influenza in domestic poultryLow 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 Slide7
Avian influenzaDisease caused by infection with avian (bird) influenza (flu) Type A virusesViruses 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. Slide8
Avian influenzaAvian 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
.Slide9
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 humansEasily transmissible from person to personSocial and economic impacts Slide10
Emergence of novel viruses: MutationAntigenic Driftthrough small changes in the virus, continually
over timeResults in new virus strains; unrecognized
by antibodies to earlier influenza strainsAntigenic ShiftSudden, major change; Results in
a new influenza virus that can infect humans
and is unrecognized
by antibodies Slide11
Emergence of novel viruses: Mutation and
Reassortment 1
1. Mutation
Human virus
2.
Reassortment
Avian virus
Reassortant
Human- Avian
virusSlide12
Emergence of novel viruses: Mutation and Reassortment 2
1. Mutation
Human virus
2.
Reassortment
Avian virus
Reassortant
Human- Avian
virusSlide13
Avian Influenza virus in Uganda16/01/2017 - 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:
http
://
www.oie.int/wahis_2/public/wahid.php/Reviewreport/Review?page_refer=MapFullEventReport&reportid=22359Slide14
Avian Influenza virus in UgandaHighly pathogenic avian influenza virus A(H5)Districts: Kachanga
, Bukibanga, Bukakata, Masakacontinuous 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:http://www.oie.int/wahis_2/public/wahid.php/Reviewreport/Review?page_refer=MapFullEventReport&reportid=22359Slide15
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
27/01/2017
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)
Slide16
Map of outbreak locations -UgandaSource: http://www.oie.int/wahis_2/public/wahid.php/Reviewreport/Review?page_refer=MapFullEventReport&reportid=22359Slide17
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, AfricaAlthough the likelihood of human infection with the A(H5N8) virus is low, if cannot be
excluded, based
on current and limited information to
date. Slide18
HPAIDuring 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 SwitzerlandMany of these recent detections were associated with mortality in wild birds.
Source: http
://www.who.int/influenza/human_animal_interface/avian_influenza/riskassessment_AH5N8_201611/en/Slide19
Human infectionsTo date, no human cases of infection with influenza A(H5N8) have been detected.Human cases with related clade 2.3.4.4 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
).Slide20
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 environmentsHigh mortality in humans (about
60
%) Slide21
Avian Influenza A(H5) in TanzaniaNo 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 planReview of stocks: PPEs, oseltamvirPrepositioning in WHO regional sites (IST) Slide22
Influenza surveillance in TanzaniaAlert 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 Slide23
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).Slide24
Thank you