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The joy of poultry


The joy of poultry

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									avian flu
                   The joy of poultry
                   Dr Robyn Alders (BSc (Vet) ’83, BVetSc ’84) is Associate Professor at Tufts
                   University’s International Veterinary Medicine Program. She has spent the
                   greater part of her career overseas. Nevertheless, her work directly affects the
                   health and welfare of Australians and the global implications of her research
                   are far reaching. From Boston, Massachusetts she answered questions put to
                   her by Diana Simmonds

                   Q    How did you start on the path
                        you've taken? (Where do you come
                   from and how did it all happen?)
                                                              can be sold or bartered to pay school
                                                              fees, or buy medicine and clothes.
                                                              Poor families rarely consume their
                                                                                                           found that the reduction in support
                                                                                                           of and attention to animal quarantine
                                                                                                           regulations were significant. The
                                                              birds as they consider this an absolute      Australian animal health network

                   A    I was born and raised on a beef
                        cattle and sheep farm just outside
                   Taralga, on the Southern Tablelands
                                                              luxury. They never know what crisis
                                                              tomorrow may bring. By preventing
                                                              outbreaks of Newcastle disease in
                                                                                                           mounted an effective control
                                                                                                           response but the number of horses
                                                                                                           and geographical area involved was
                   of NSW. Much of my childhood was           these village flocks through regular          relatively small. Indonesia has 444
                   spent on the back of a horse and I         vaccination using thermo-tolerant            districts, 33 provinces, 17,000 islands
                   entered the Faculty of Veterinary          vaccine (developed through research          and many, many tens of million
                   Science at Sydney University with          funded by the Australian Centre for          poultry.
                   the intention of becoming a specialist     International Agricultural Research),
                   in equine medicine. Somewhere              families can both increase their flock        The HPAI control and eradication
                   along the way, I became interested         size and enjoy a chicken or egg dish.        program in Indonesia is based on
                   in international development (my           Almost everywhere you travel in the          Participatory Disease Surveillance
                   time at Wesley College probably had        developing world, village poultry            (PDS) techniques developed in the
                   something to do with this) and, after      are part of the fabric of life. This is      campaign against rinderpest (cattle
                   completing my PhD in veterinary            certainly the case in Indonesia where        plague). What does PDS actually mean in
                   immunology at the John Curtin              I now regularly make inputs into the         practical terms?
                   School of Medicine at ANU, I made          Avian Influenza Control Program
                   the unusual decision to work on            implemented by the Indonesian                Participatory disease surveillance
                   a local contract at the new School         Ministry of Agriculture and the FAO.         relies on the knowledge of farmers
                   of Veterinary Medicine within the                                                       to identify disease in their animals
                   University of Zambia. I worked there       Highly Pathogenic Avian Influenza             and then share that information
                   for three years and it’s one of the best   (HPAI) is endemic in Indonesia. What         with animal health teams trained in
                   decisions I have ever made.                does this mean for Australia (and the rest   participatory methodologies. This
                                                              of the world) in terms of health, disease    approach is very useful in situations
                   As a consultant to the FAO (United         prevention and how it may spread?            were laboratory services are either not
                   Nations Food and Agricultural                                                           easily accessible or not functioning.
                   Organisation) your title is Senior         The current HPAI crisis has an               This approach worked well with
                   Technical Advisor - Poultry Health and     interesting history. Avian Influenza          rinderpest as the clinical signs of
                   Production. You have more than 20 years    subtype H5N1 was identified in                disease are relatively distinctive. The
                   experience and a PhD in immunology.        Indonesia in 2003 and a number               Indonesian Ministry of Agriculture,
                   Why poultry?                               of other Southeast Asian nations.            FAO and Tufts University have
                                                              Indonesia is not an exporter of poultry      devoted considerable attention
                   Why poultry? Well, I wish I could          or poultry products and nations such         to adapting these participatory
                   say that was because of the great          as Papua New Guinea and Timor-               methodologies to working with
                   lectures given to us by Dr Sinkovic        Leste, that share a land border              poultry (as chickens infected with
                   in the final year of our vet course.        with Indonesia, currently remain             HPAI can look just like birds infected
                   Sadly, while I now understand that         free of HPAI. Veterinary services in         with Newcastle disease or fowl
                   Dr Sinkovic did deliver excellent          Indonesia suffered significant cuts in        cholera); and developing participatory
                   lectures, I was not really interested.     funding following the Asian economic         responses that enable communities
                   However, when I arrived in Southern        crisis and the introduction of               to be involved with outbreaks
                   Africa, I came to understand that in       decentralisation effectively removed         control measures. The program has
                   their mixed farming systems 10-20          the chain of command so important            moved on from PDS to participatory
                   per cent own cattle, 30-40 per cent        to animal disease control. It’s a little     disease prevention and control
                   own goats and sheep, but almost            like the incursion of equine influenza        that supports the strengthening of
                   everyone owns a few village chickens.      (EI) into Australia. I believe that          veterinary services and community
                   These chickens are a living bank that      the investigation of the EI outbreak         empowerment.
28 SAM Summer 09
The FAO estimates that rinderpest is
now almost eliminated with the exception
of a relatively small area of Africa
encompassing northern Kenya, southern
Somalia and parts of Ethiopia. As this
area is the most remote and lawless region
in the world is eradication realistic?

Dr Bryony Jones, a British veterinarian      African and
                                             Indonesian chooks
who has worked on the Rinderpest
                                             with their keepers;
Eradication Campaign for many                Robyn Alders
years, told me recently that structured      consults (above)

                                                                   SAM Summer 09 29
The sharp end of the   surveillance is being conducted in the        in the short-term the aim is to work       environment. On the other, huge efforts
egg industry
                       areas that you mentioned right now            village by village, poultry farm by        have been made to eradicate rinderpest
                       and that if no trace of disease is found,     poultry farm and district by district to   in cattle that are basically status symbols.
                       then eradication will be proclaimed in        control disease and then to keep it out.   Can you explain?
                       early 2009.                                   The bio-security practices put in place
                                                                     will also help to improve farmers’         I guess most things in life are
                       And as Indonesia consists of 1.4 billion      understanding of disease transmission      contextual. Cutting down rainforests
                       chooks and 230 million people who speak a     and reduce the circulation of other        in the Amazon to raise cattle would
                       number of languages across the islands, how   poultry diseases. This should              not appear to be a great move from
                       does an eradication program work there?       contribute to improved poultry             the point of view of ecological
                                                                     production and this is important in an     sustainability. However, there are
                       The HPAI control program consists             increasingly urbanised society.            ecosystems that have evolved over
                       of surveillance, outbreak response,                                                      centuries where grazing and browsing
                       prevention activities and monitoring.         Given that birds fly, poo and die, is       wildlife and livestock are an integral
                       In April of this year, a new disease          eradication really possible?               part of the system. Cattle are important
                       prevention and control system was                                                        status symbols in many cultures.
                       introduced that enables all villages          As I mentioned before, eradication         They also make crucial contributions
                       in the program area to be classified           will not happen quickly, however,          to human nutrition (in terms of meat
                       as “Apparently Free,” “Infected,”             it must remain the long-term goal.         and milk) and traction (oxen power
                       “Controlled” or “Suspect.” Each of            Putting systems in place to control        ploughs, wagons and power mills) to
                       these categories has a set of activities      and eventually eradicate HPAI will         name the most obvious benefits. With
                       to be implemented in collaboration            also make us better prepared to deal       increasing international trade, taking
                       with communities and commercial               with the next emerging infectious          one killer disease out of the equation
                       producers that aim to either keep             disease.                                   is a step in the right direction. It also
                       areas free of disease or to move                                                         reminds us that some key diseases can
                       infected areas towards freedom and            I'm puzzled. On the one hand green         be contained and eventually eradicated
                       then maintaining that status. So while        groups say that raising cattle for         if nations decide to work together
                       eradication is clearly a long-term goal,      human consumption is harmful to the        towards that common goal.
30 SAM Summer 09
              Getting back to poultry. Has AI always       the environment but it is currently             cell-mediated immunity. The recent
              been around or is it a modern thing? If      impossible to guarantee that another            revolution in biotechnology has
              yes, why is it now becoming a problem? If    human influenza pandemic can be                  greatly increased our knowledge of
              no, what has triggered it?                   prevented. All it takes is one shift,           genes and how they are involved
                                                           one re-assortment event and it will             with the control of the immune
              The first documented report of HPAI           be difficult to contain because of the           response. Genomics refers to the
              occurred in 1878 in Italy. Outbreaks         speed with which people now move                study of all genes of an organism and
              of the disease have been rare until the      around the globe.                               inter-relations between genes. Host-
              early 1990s when outbreaks became                                                            pathogen interactions are important
              more frequent. In Australia, we've had       Is AI moving or likely to move into other       as they are directly associated with
              two known outbreaks prior to 1990            bird populations - ratites (large flightless     the consequences of infection. For
              and three subsequently but none have         birds), for instance?                           example, there is increasing evidence
              involved the H5N1 subtype. Wild                                                              in humans that individuals most
              waterfowl are considered the reservoir       There have already been reports                 several affected by infection with the
              of HPAI virus and normally infection         of emus, ostriches and rheas being              H5N1 virus mount an exaggerated
              is asymptomatic. Most commentators           infected with Low Pathogenicity                 immune response to the infection
              associate the huge increase in               AI viruses. In 2004, there was an               that increases the severity of disease.
              commercial poultry production                outbreak of a different strain of HPAI          Looking for biotechnological means
              (more than doubled since the 1980s),         known as H5N2 in ostriches in South             to develop disease resistance in
              increased international trade and            Africa.                                         animals, including poultry, is an active
              increasing human population with the                                                         area of research. With the growing
              increase in HPAI outbreaks.                  Can you tell us something about the             number of microorganisms resistant
                                                           immune system in poultry and how that           to pharmaceutical interventions,
              There was an item in the press recently      affects the bird’s defence against pathogens?   biotechnological solutions to disease
              citing a new study, which reveals that                                                       control problems that are safe and
              battery hens are healthier than free-range   Fundamentally, the immune                       affordable are becoming more
              birds. What do you think of that?            system of birds is similar to that              important than ever.
                                                           of mammals. In fact, the study
              I don't know the press item that you         of avian immunology has made                    In your opinion, what are the important
              mentioned, but once again, it would          significant contributions to the study           lessons to learn from this avian
              depend on the specific conditions             of immunology in general. The                   influenza crisis?
              concerned. Birds raised in cages may         first recorded attenuated vaccine
              have fewer disease outbreaks if good         was discovered by Pasteur and                   The avian influenza crisis has
              bio-security is practiced but they also      directed against fowl cholera. The              reminded us that we live in an
              need to be fed a balanced diet and           “B” lymphocytes that are associated             increasingly small world; what
              have adequate space. Free-range              with the production of antibodies               happens in one country can
              conditions vary considerably from            are “bursa-derived lymphocytes”                 potentially impact on millions of
The first      commercial birds having access to a          named after the Bursa of Fabricius, a           people worldwide. It also reinforces
documented    limited open range with feed being           lymphoid organ of birds.                        the importance of the three pillars
              supplied entirely via feed troughs to        One aspect of poultry immunity that             of a stable society: agriculture,
outbreak      village poultry that free-range over a       makes a practical difference is that            education and health. For the first
of HPAI       wide area and scavenge for almost all        the duration of immunity stimulated             time in human history, more people
              their feed. As free-range birds may          by the current range of conventional            now live in cities than in rural areas.
occurred      come into contact with wild birds, this      vaccines against diseases such as AI is         Stable urban societies rely on safe and
in Italy in   may increase their likelihood of being       relatively short-lived. Poultry require         efficient agricultural production and
1878          exposed to some diseases, including          a primary vaccination against AI, a             so politicians can no longer continue
              HPAI. Once disease incursion occurs,         booster after three weeks and then              to ignore farmers. When a poor
              it usually spreads more slowly in            revaccination every three months                formal education system results in a
              free-range poultry than in intensively       to maintain adequate levels of                  significant proportion of a society not
              raised poultry.                              immunity. Conventional AI vaccines              understanding that infectious agents,
                                                           are inactivated vaccines that are               rather than supernational forces, are
              We worry about the HPAI virus mutating       administered via injection and so this          associated with disease, prevention
              and becoming a fully human disease. Is       increases the logistical complications.         and control activities will always be
              this likely to happen? Is it preventable?                                                    difficult. An important lesson learnt in
                                                           Can you explain in non-scientific terms          many societies is the need for effective
              It is impossible to predict when             aspects of poultry immunology, genomics         community public awareness. The
              a HPAI virus, and it may be a                and manipulation of host-pathogen               crisis has also provided us with a
              subtype other than H5N1 that shifts          interactions?                                   long-overdue opportunity to build
              or re-assorts to become a strain                                                             bridges between human and animal
              that transmits between people.               As mentioned before, we have                    health services. It may just be that
              The assumption is that the more              been studying the immune system                 the combination of the AI crisis and
              HPAI virus there is, the greater             of birds for a very long time and it            concerns about global climate change
              the probability of a new pandemic            has helped us to understand the                 will provide us with the impetus we
              strain emerging. We are working to           two arms of the immune response:                need to embrace and benefit from the
              reduce the amount of HPAI virus in           humoral (antibody) immunity, and                One World, One Health concept. SAM
                                                                                                                             SAM Summer 09 31

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