Re: UCLA scientists find H1N1 flu virus prevalent in animals in Africa
INFLUENZA A (H1N1) 2009, ANIMAL (04): CAMEROON, PORCINE, 2010
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A ProMED-mail post
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Date: Thu 22 Sep 2011
Source: UCLA (University of California, Los Angeles) Newsroom [summ.,
edited]
<http://newsroom.ucla.edu/portal/ucla/ucla-life-scientists-find-h1n1-215707.aspx>
UCLA scientists find H1N1 flu virus prevalent in animals in Africa
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In one village in northern Cameroon, a staggering 89 percent of the
pigs studied had been exposed to the H1N1 virus, commonly known as the
swine flu.
"The pigs were running wild in that area," said lead author Kevin
Njabo, a researcher in UCLA's department of ecology and evolutionary
biology and associate director of the Center for Tropical Research.
Njabo and his colleagues randomly collected nasal swabs and blood
samples from domestic pigs that were part of 11 herds in villages and
farms in Cameroon in 2009 and 2010. The results are published in the
current issue of Veterinary Microbiology, a peer-reviewed scientific
journal specializing in microbial animal diseases [see commentary].
Nasal swabs can detect a current infection, and blood samples reveal
past exposure to a virus. Because an active infection lasts only about
5 days, "we have to be lucky to get an active infection in the field,
but evidence of the infection stays in the blood."
In the village in northern Cameroon, Njabo found 2 pigs with active
H1N1 infections, and virtually every other pig had evidence of a past
infection in its blood.
"The pigs got H1N1 from humans," Njabo said. "The H1N1 virus that we
found in livestock in Cameroon is virtually identical to a virus found
in people in San Diego just a year earlier, providing an astonishing
example of how quickly the flu can spread all over the globe.
"The discovery of H1N1 in African swine is also important because it
shows how farming practices can trigger disease outbreaks and suggests
opportunities for improving human and livestock health. Our studies
indicate that H1N1 infections are more common in swine that wander
freely in villages than in animals that are confined to farms."
The biologists used a diagnostic test called ELISA -- enzyme-linked
immunosorbent assay -- to test for potential viruses. ELISA revealed
the pigs had the human strain of H1N1.
Viruses in pigs can mix into a much more virulent strain that can
spread extremely fast, Smith and Njabo warned.
"We are studying the interface between viruses in humans, wild animals
and domestic animals and how viruses move among them," Njabo said.
"This particular H1N1 strain is ubiquitous," said Smith, who is also a
professor of ecology and evolutionary biology and a member of UCLA's
Institute of the Environment and Sustainability. "When different
strains of influenza are mixed in pigs, such as an avian strain with a
human strain, you can get new hybrid strains that may affect humans
much more severely and can potentially produce a pandemic that can
allow human-to-human infection. This is how a pandemic can arise; we
need to be very vigilant.
In addition to studying pigs, Njabo and colleagues have also collected
samples from hundreds of wild birds, ducks and chickens in Cameroon
and Egypt. Their colleagues at other institutions are conducting
similar studies in China, Bangladesh and elsewhere.
Since 2007, Njabo has gone to Cameroon 2 to 3 times a year to collect
samples and is there currently. He informed the government's Ministry
of Livestock, Fisheries, and Animal Industries of the findings to try
to reduce the spread of the disease. Smith, Njabo, and colleagues will
hold a workshop in Cameroon next year [2012] to tell people how to
raise pigs in a way that reduces the risk of disease.
The research was conducted under the auspices of the Zoonotic
Influenza Collaborative Network, led by the Fogarty International
Center at the National Institutes of Health. The collaborative network
is supported by international influenza funds from the Office of the
Secretary of the Department of Health and Human Services.
[Byline: Stuart Wolpert]
--
Communicated by:
ProMED-mail
<promed@promedmail.org>
[The cited paper is:
KY Njaboa, TL Fullera, A Chasara, et al: Pandemic A/H1N1/2009
influenza virus in Swine, Cameroon, 2010. Vet Microbiol. 2011; in
press, accepted manuscript. doi:10.1016/j.vetmic.2011.09.003. Received
5 Apr 2011; revised 30 Aug 2011; Accepted 5 Sep 2011. Available online
12 Sep 2011 at
<http://www.sciencedirect.com/science/article/pii/S0378113511004974>
(subscription required for the full paper).
"Abstract
--------
Although swine origin A/H1N1/2009 influenza virus (hereafter "pH1N1")
has been detected in swine in 20 countries, there has been no
published surveillance of the virus in African livestock. The
objective of this study was to assess the circulation of influenza A
viruses, including pH1N1 in swine in Cameroon, Central Africa. We
collected 108 nasal swabs and 98 sera samples from domestic pigs
randomly sampled at 11 herds in villages and farms in Cameroon. pH1N1
was isolated from 2 swine sampled in northern Cameroon in January
2010. Sera from 28 percent of these herds were positive for influenza
A by competitive ELISA and 92.6 percent of these swine showed cross
reactivity with pandemic A/H1N1/2009 influenza virus isolated from
humans. These results provide the 1st evidence of this virus in the
animal population in Africa. In light of the significant role of swine
in the ecology of influenza viruses, our results call for greater
monitoring and study in Central Africa."
In the paper's chapter 'Materials and methods', the authors inform
that swine from some of the sampled herds showed mild respiratory
signs but no swine deaths were recorded during the study period.
The following statements on 'Pandemic influenza A/H1N1 (2009)' in
animals have been selected from OIE's press pack, available at
<http://www.oie.int/en/for-the-media/press-packs/pandemic-h1n1-2009/>:
1. The OIE has been actively and closely monitoring, together with its
partner organisations, the development of the ongoing pandemic since
the detection of the pandemic H1N1 2009 virus in humans in April
2009.
2. The OIE has continuously encouraged all of its Member Countries to
intensify their surveillance for potential influenza virus infections
in animals, including swine. The OIE has also recommended that
adequate biosecurity measures be taken at the farm level to minimize
the infection from humans to animals and amongst animals. The OIE does
not recommend to cull infected animals as a measure to protect animal
health and human health from the pandemic H1N1 2009.
3. The OIE has asked its Members to notify occurrences of pandemic
H1N1 2009 in animals, qualifying this as an "emerging disease" on
notification forms. Prompt reporting of pandemic H1N1 2009 in
different animal species demonstrates that the international community
is responding and mobilising in the interests of all (see list
below).
4. The OIE ensures that all information on the virus and its spread is
shared amongst all stakeholders. OIE Reference Laboratories and
Collaborating Centres, primarily through OFFLU -- the OIE/FAO joint
network of expertise on animal influenzas -- play a key role in
developing technical guidance for the international community, thus
providing the animal and human health sectors with basic information
on animal influenzas.
The following list shows OIE members which have already notified
Pandemic Influenza A H1N1 (2009) in animals as an emerging disease:
1. 5 May 2009: A/H1N1 influenza, Canada (immediate notification)
2. 31 Jul 2009: Influenza A subtype H1, Australia (immediate
notification)
3. 21 Aug 2009: Influenza A H1N1, Chile (immediate notification)
4. 18 Sep 2009: Pandemic Influenza A H1N1 (2009), United Kingdom,
North Ireland (immediate notification)
5. 29 Sep 2009: Pandemic A/H1N1 2009 virus, Ireland, (immediate
notification)
6. 12 Oct 2009: Pandemic A/H1N1 2009 virus, Norway, (immediate
notification)
7. 21 Oct 2009: Pandemic Influenza H1N1 (2009), Japan, (immediate
notification)
8. 23 Oct 2009: Pandemic H1N1 2009, Canada, (immediate notification)
9. 27 Oct 2009: Pandemic influenza A/H1N1 virus, Iceland, (immediate
notification)
10. 26 Nov 2009: Pandemic influenza A/H1N1, Indonesia, (immediate
notification)
11. 30 Nov 2009: Pandemic influenza A/H1N1 2009, Finland, (immediate
notification)
12. 30 Nov 2009: 2009 pandemic A/H1N1 influenza virus, United States
of America, (immediate notification)
13. 4 Dec 2009: Pandemic A/H1N1 virus, Italy, (immediate
notification)
14. 7 Dec 2009: 2009 Pandemic H1N1 influenza, Mexico, (immediate
notification)
15. 14 Dec 2009: Pandemic Influenza H1N1 2009, Thailand, (immediate
notification)
16. 23 Dec 2009: Pandemic influenza H1N1, Korea (Rep. of), (immediate
notification)
17. 23 Dec 2009: Pandemic influenza A/H1N1 2009, Russia, (immediate
notification)
18. 9 Jan 2010: Pandemic influenza A/H1N1 (2009), Denmark, (immediate
notification)
19. 12 Jan 2010: Pandemic A/H1N1 virus, Italy, (immediate
notification)
20. 20 Jan 2010: Pandemic A/H1N1 virus (2009), France, (immediate
notification)
21. 20 Jan 2010: Pandemic influenza H1N1 (2009), Japan, (immediate
notification)
22. 25 Jan 2010: Pandemic Influenza A H1N1 (2009), Serbia, (immediate
notification).
23. 7 Sep 2010: Pandemic Influenza A/H1N1 (2009), Chinese Taipei
(immediate notification).
An OIE Reference Laboratory for Avian Influenza (Padova, Italy) was
one of the 3 institutes behind the new paper on H1N1 in swine in
Cameroon.
Cameroon is expected to submit a notification and join the list. -
Mod.AS]
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