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Solving the mystery of what tick-borne

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Solving the mystery of what tick-borne Powered By Docstoc
					                                                                                                                                  ANIMAL HEALTH


A T(R)ICKY
PROBLEM
SOLVED

Livestock represent
a valuable resource
for poor farmers
throughout Asia, as
a source of draft
power, through
the sale of young
animals and for
food security.                                                                                                                               Improved


                            S
Animal diseases                     olving the mystery of what tick-borne          control of tick fever have been developed in the            returns:
                                    diseases of cattle are present in the          key laboratories in Manila and Davao that service            projects
are a constant                                                                                                                                   benefit
                                    Philippines and their impact on the            the major cattle producing and cattle importing
threat to the               country’s 2.4 million cattle has been the subject      areas in the north and south of the Philippines.        smallholders
health of livestock.        of investigations by researchers from that country          These laboratories are now recognised                     in the
                                                                                                                                            Philippines.
Developing                  and Australia.                                         reference centres for the rest of the country
                                                                                                                                           Photo: ACIAR
                                In the Philippines, as elsewhere, ticks can be     and models for establishing similar expertise in
improved testing,
                            a nuisance. But the real problem is the diseases       Regional Animal Disease Diagnostic Laboratories
monitoring and              they can transmit with a single bite. In susceptible   (RADDL) throughout the Philippines.
controls for animal         cattle, tick-borne diseases can cause dramatic              The completion of serological surveys has
health is the focus         losses in productivity and frequently death.           established that both diseases occur throughout
                                The impact of tick-borne diseases in the           the country. Serological tests for babesiosis
of a number of
                            Philippines has not been as severe as elsewhere        and anaplasmosis are now in routine use in the
ACIAR-supported             due to the inherent resistance of local breeds. That   Philippines, and DNA-based tests capable of
projects.                   situation could change rapidly as the Philippine       differentiating between Australian and Philippine
                            government embarks on a program to build               disease strains have been developed.
                            more profitable beef and dairy industries through            These research outcomes are vital in the
                            importation of better breeding stock.                  ongoing development of a more substantial
                                But knowing where the diseases are present         livestock industry in the Philippines, an important
                            and how prevalent they are, especially when acute      Government initiative that stands to benefit
                            symptoms are rare in local cattle, is difficult.         smallholder farmers particularly.
                            Developing the capacity for accurate testing and            The greater the profitability of livestock
PROJECT:                    diagnosis is an urgent priority to support this        industries, both through diversification such as
AS2/2000/098 Bovine         expansion.                                             into dairy cattle, and through healthier more
babesiosis and                  Helping speed up this process has been             productive cattle, the greater the opportunities for
anaplasmosis in the         the focus of ACIAR-supported research by the           smallholders to reap increased returns.
Philippines: developing a   Queensland Department of Primary Industries                 The project has also contributed to the
research and diagnostic     and Fisheries and the Bureau of Animal Health in       smooth operation of the live cattle trade between
capability                  the Philippines.                                       Australia and the Philippines, an outcome that is
Contact:                        Prior to this research the types of tick-borne     already paying dividends.
ACIAR, Dr Bill Winter,      diseases, their distribution and prevalence were            The project has shown that the introduction
Research Program            not known. The two diseases of major concern           of Australian strains of Babesia and Anaplasma
Manager, Animal             to Philippine authorities are babesiosis and           in imported cattle is not a problem, as the same
Sciences 2,                 anaplasmosis, collectively known as tick fever.        parasites are already present throughout the
+61 2 6217 0500,                By introducing appropriate testing, survey         Philippines.
winter@aciar.gov.au         methodologies and training of local researchers             The result should be an improved trading
                            to the Philippines, these unknowns have all been       relationship between Australia and the Philippines
                            addressed.                                             with less likelihood of trade disputes as a result of
                                Centres of expertise in the diagnosis and          tick fever outbreaks in imported cattle.

SEPTEMBER 2004                                                          15                                        PARTNERS in Research for Development
ANIMAL HEALTH




BID TO BEAT
PARASITE
GOES TO
THE FARM



                      C
                                 ontrol of one of South-East Asia’s most pervasive            become less fertile. “The average liver weighs six kilograms. The
                                 livestock diseases, fasciolosis, is about to enter a new     liver of an animal with fasciolosis weighs just 3.7 kilograms on
                                 phase as researchers begin to wrestle with the issue         average, so you can see the extent of the damage. In fact, to
                                 of translating science into new stock management             explain to farmers that it was a disease caused by a parasite we
                      practices on-farm.                                                      started showing them livers from the abattoir. We’ve sometimes
                           Studies in Indonesia, the Philippines and Cambodia in              found over 700 flukes in a single liver.”
                      recent years have brought the mystery condition in from                     Dr Sothoeun says four years were spent building up scientists’
                      the dark, in terms of understanding its epidemiology, but               knowledge of the epidemiology – when the animals are infected,
                      scientists say the next phase of the project – control and farm         where they are infected and how they are infected. “We learned
                      management – may be the biggest challenge.                              that infections occur in specific months – from November to
                           Research has revealed that more than 50 percent of cattle and      April-May, and there are no infections from June to October.”
                      buffaloes are infected with the fasciolosis parasite, and the symptoms       The initial four-year study produced several
                      – weight loss, diarrhorea and animals becoming too weak to work,        recommendations based on the following findings:
                      to the point that some die – have been prevalent for so long that       n a high prevalence (more than 50 percent);
                      farmers will be hard to convince that there is an answer.               n November to April-May being the infection period;
                           In Cambodia, the research into the epidemiology as well as         n the practice by farmers to sell and replace infected animals as
                      the coming work on developing effective extension services has           a way of trying to stay ahead of the mystery disease;
                      been led by Dr Suon Sothoeun, who is now deputy director of             n the significant liver damage; and
                      the Department of Animal Health and Production (DAHP).                  n a 50 percent drop in fertility rates. Instead of producing an
                           Fasciolosis was the subject of Dr Sothoeun’s PhD in 1990, and      offspring every year, inter-cowing among infected animals
                      it was a meeting four years later with ACIAR’s research program         stretched out to 24 to 25 months.
                      manager, Dr John Copland, and Dr Bruce Copeman from James                   These factors have led to new livestock management
                      Cook University that led to Cambodia’s involvement in the 1998-         recommendations that now have to be incorporated into
                      2002 project to fully establish the disease’s epidemiology.             effective extension and education programs.
                           Dr Sothoeun says fasciolosis is caused by the parasitic liver          Dr Sothoeun says this will need further research, but in
                      fluke Fasciola gigantica and has now been shown to be the most           the meantime researchers have developed a proposed control
                      important parasitic disease of cattle and buffalo in the humid           calendar. The calendar is based on the knowledge that infection
                      wet tropics.                                                            peaks in April and is slightly different in three distinct
                           Aside from making animals too weak to pull a plough,               categories of grazing:
                      he says infected animals suffer serious liver damage and also            n grazing out in the fields;                     u PAGE 18

PARTNERS in Research for Development                                           16                                                             SEPTEMBER 2004
SUCCESS WILL                                                                                                                            1   Adult liver fluke
                                                                                                                                            in bile duct

                                                               5
BE NO FLUKE
                                                                   Cattle infected when grass
                                                                   and water consumed
                                                                                                                                                         2      Eggs in
                                                                                                                                                                faeces




By JANET LAWRENCE




A
         “fluke” can be a lucky accident or coincidence.
         Another Oxford Dictionary definition of fluke is
         “any parasitic flatworm of the Class Digenea or
Monogenea, including liver flukes and blood flukes”.
     For the team of scientists dedicated to the study of
the large parasitic flatworm Fasciola gigantica, success        4   Second stage larvae leave snail.
                                                                   Many attach to vegetation below surface of water   3   Eggs hatch in water; free swimming larvae
                                                                                                                          infect snail and multiply as second stage larvae
has been no lucky accident. It has come from years of
dedicated, painstaking investigation to uncover the life           least nine months. Such a straightforward treatment could                         LIFE CYCLE OF
cycle of this parasite and to determine ways to control the        have a major impact on transmission of the parasite.                      FASCIOLA GIGANTICA
disease fasciolosis that results from its invasion of cattle           The second line of research revealed that the immature               The tropical liver fluke’s life
and buffalo in the wet tropics.                                    phases of Echinostoma revolutum, a fluke that commonly                      cycle begins when worms
     Fasciolosis causes huge losses in animal production.          infects village ducks and chickens, could aggressively                  lodged in the bile duct of an
The scientists involved in early ACIAR research in Indonesia       displace Fasciola gigantica in the intermediate host                 infected animal produce eggs
in the mid-1980s examined the effect of the condition on           snail when the two were present together. The scientists                  that pass out in the faeces.
the work output of large ruminants in Indonesia. They              recognised the potential for an inexpensive, practical                       The eggs hatch in water,
concluded that its presence caused up to $A100 million             control procedure.                                                          producing free-swimming
annual loss in production.                                             The knowledge gained from the Indonesian work gave                  larvae that proceed to infect
     Infected animals are anaemic and, compared to                 new hope for control of the problem in Indonesia and other           water snails. About six weeks
healthy counterparts, are slow growing and achieve a               South-East Asian countries. In July 1998 a four-year ACIAR                 later the snails deposit the
lower final weight and size. As well as lowering meat and           project commenced, focusing on Indonesia, the Philippines             larvae (cercariae) in the water
milk production, such animals produce fewer calves. They           and Cambodia. The project’s main purpose was to extend                   of a rice field and the larvae
also have reduced working capacity, which is especially            the work of the earlier project, developing suitable, cost-         become small cysts (known as
significant in countries where farmers rely on cattle               effective strategies for the control of the parasites, and            metacercariae). These float in
and buffalo to cultivate the land. But when a disease is           combating the problem on a regional rather than country-            the water, sink into the mud or
so common and unspectacular, farmers have a certain                specific basis.                                                      attach themselves to the stalks
resignation about it and the poor condition of animals is              In the new project, the scientists extended their study          of the rice plants below water
considered normal.                                                 to measure benefits of control of fasciolosis. Extension                  level. Livestock are infected
     Indonesian and Australian scientists were looking             to promote control of fasciolosis was also an important                when they eat the vegetation
for ways to lift farm productivity and improve the lot of          component of the project.                                                           or drink the water.
the smallholder, and recognised that reducing the effects              Abattoir surveys in Cambodia and the Philippines
of fasciolosis would have major benefits. They set out to           produced basic biological statistics about seasonal and
unravel the life cycle of the fluke, which spends its adult         regional prevalence, parasite load and host conditions.
life in the body of the animal and an intermediate phase           Problems associated with biological control using ducks
in a water snail. This early work was reported by Robert           were investigated.
Lehane in Partners No. 11 in 1998 (see chart, right).                  Scientists had discovered that a second parasite
     The team, led by Dr Bruce Copeman from James Cook             infecting the ducks, a blood parasite called a schistosome,
University and Dr Suhardono of Indonesia’s Research                had a free-living stage in the water that burrowed into
Institute for Veterinary Science, discovered that the main         human skin, causing an itchy, unpleasant dermatitis – a
source of infection for animals was recently harvested rice        major deterrent in the campaign to encourage farmers
fields when the animals graze on the stubble.                       to keep ducks! The solution was to use village chickens
     They recognised that village rice farming provides the        instead of ducks.
ideal environment for proliferation of tropical liver fluke,            The overall output of the project was to demonstrate
with a strong link between the cycle of infection and the          that the application of a scientifically-based fasciolosis
agricultural and husbandry practices of the smallholders.          control program can alleviate poverty through increased
     Their studies produced two promising outcomes.                animal production.
The first was the determination that a single dose of the               The initial impact of the research was restricted to the
medication triclabendazole dispensed to animals in July            sites where the research took place, but animal owners
completely eliminated Fasciola eggs from their faeces for at       who participated in the research learnt how to           u

SEPTEMBER 2004                                                                   17                                           PARTNERS in Research for Development
   ANIMAL HEALTH




u increase the income they derived               Three scientists
  from animal production.                   associated with the
       The scientists developed             research received ACIAR                      No fluke: research leader Dr Suon Sothoeun.
  options for fasciolosis control           John Allwright Fellowships to
  that required minimal use of              undertake postgraduate studies               u FROM PAGE 16
  anthelmintic medications. The             in Australia. Elizabeth Molina is            n grazing   in areas adjacent to households; and
  control program is based on the           undertaking pathology studies                n grazing   in the immediate household area.
  following five elements:                   on cattle and buffaloes in the                    It has been shown that January to April is the infection
  1. prevent animals grazing in rice        Philippines. Her work will help to           period for ‘in-the-field’ grazing, September to December for
     fields adjacent to a village or         build up a comparative picture               ‘near households’ and September to April for animals grazing
     cattle pen for up to a month           of the fluke resistance in these              inside household enclosures.
     after harvest, to reduce their         species. The study is being                       “So we can now recommend corresponding treatments,”
     risk of ingesting the infective        completed by analysis of the                 he says. “For in-the-field cattle, we recommend treating with
     metacercariae;                         samples at James Cook University.            triclabendazole in May when we have four months during which
  2. feed only the top two-thirds of             Another John Allwright                  infection won’t occur. For cattle grazing adjacent to households
     freshly cut rice stalks, cut 20 to     Scholar studying at James Cook               we are recommending albendazole in May and again in July. Both
     30 centimetres above ground            University, Tum Sothyra, has used            triclabendazole and albendazole are oral treatments.
     level, to avoid feeding the            Geographic Information Systems                    “For cattle around households we are recommending
     metacercariae;                         (GIS) technology to construct a map          dovenil by injection, also in May and July.”
  3. kill metacercariae on the lower        showing the risk of fasciolosis in                However, before farmers will accept the cost of these
     third of the rice stalks by exposing   Cambodia. GIS technology holds               controls they will need to fully understand the disease and the
     them to sunlight for three days        the promise of saving resources              costs they are already incurring because of the disease.
     before feeding to cattle;              through better targeting the high-                Dr Sothoeun says a cost-benefit study will be an essential part
  4. before using cattle or buffalo         risk areas for application of control        of the new program. “We have to prove to farmers and to the
     dung as fertiliser in rice fields,      measures.                                    government that fasciolosis is the problem that we say it is so that
     mix it with duck or chicken                 The third scholar, Eny                  we can get government support for a national control program.
     manure that has been naturally         Martindah, is a PhD candidate                     “We also have to test farmers attitudes to the controls we are
     infected with the poultry fluke         at the University of Queensland,             proposing and to determine which extension methods will be
     Echinostoma revolutum; and             studying extension theory based on           the most effective – farmer meetings, or TV/radio?”
  5. treat cattle with triclabenzadole      control of fasciolosis in Indonesia.              Dr Sothoeun says this next phase will be an interesting
     about six weeks after harvesting            The stated aim of the project           challenge – turning science into on-farm change.
     the second seasonal rice crop.         was to develop extension programs                 ACIAR support is continuing through this two-year small
       These recommendations are            to introduce the control measures            project in Cambodia. Researchers will refine and validate a
  now being made available to               in South-East Asian countries.               GIS-based risk model for fasciolosis in that country, and also
  extension services in Indonesia,          Project reviewers found that a great         implement and evaluate an extension program.
  Cambodia, the Philippines and             deal of trust had been established                This will involve production of extension materials in the
  through representative networks to        between extension workers and                Khmer language. Dr Lee Skerratt is the Australian project
  Vietnam, Thailand and Laos.               the animal owners. It was therefore          leader, and Tum Sothyra, a John Allwright Scholar, is playing a
       The extension will be assisted       the basis for successful fasciolosis         pivotal role in the project’s implementation in Cambodia.
  by the availability of pamphlets          control, and also an opportunity                  This new project will help fulfill the initial research intentions
  and other material and the                to introduce other animal health             of problem solving, capacity building and extension to farmers.
  production of a laboratory manual         measures.
  that will provide technical support            A fasciolosis control network           PROJECT:
  for researchers and extension             of researchers is now well                   AS1/2002/099 Development of a model for the control
  workers. Publishing a monograph           established, giving a region-wide            of fasciolosis in cattle and buffaloes in the Kingdom of
  will complement the publication           perspective to the research effort.          Cambodia
  of research results in scientific          For instance, the project supported          Contact:
  journals and will make all the            an international workshop to                 ACIAR, Dr John Copland, Research Program Manager,
  results of this project available in      standardise laboratory procedures            Animal Sciences 1, +61 2 6217 0500, copland@aciar.gov.au
  one convenient document.                  for research into fasciolosis.

   PARTNERS in Research for Development                                             18                                                      SEPTEMBER 2004
PRACTICAL TOOLS                                                                                                                         ANIMAL HEALTH

FOR SURVEYING
ANIMAL DISEASES


W
           hen thinking of toolboxes, images of spanners,
           wrenches and screwdrivers spring to mind, but
           for many scientists throughout Asia and the
Pacific the image they have may be very different.
     Chances are that when the term toolbox is mentioned
they think of one of two books: the Survey Toolbox for
Livestock Diseases and the Survey Toolbox for Aquatic
Animal Diseases. Both books introduce readers to methods
for surveillance of animal diseases, developed specifically
for developing country contexts. At the beginning of each
is a guide offering two options.
     For those already familiar with animal health
surveillance, there is the option to carry out a survey,
including for disease prevalence, impacts on production,
disease incidence and detection.
     For workers unfamiliar with this methodology, the
option to learn more exists, directing the reader to the
appropriate chapters, prior to embarking on a survey.
Both books also include software support on CD-ROM.
     The surveillance techniques behind the Survey
Toolbox for Livestock Diseases were developed during two
ACIAR projects on animal health and diseases, the first
in Thailand between 1994 and 1996, the second in Laos
from 1996 to 1998. The author of both Toolboxes, Angus
Cameron, was involved in both projects as an Australian
Volunteers International (then known as Australia’s                 Angus used the knowledge and skills gained from
Overseas Service Bureau).                                      working in Thailand, Laos and other Asian countries
     Angus worked in the mid-1990s with the ACIAR              to write about active surveillance for livestock diseases,
project at the Northern Veterinary Research and                published as the Survey Toolbox for Livestock Diseases.
Diagnostic Centre in Lampang, northern Thailand.                    It has been widely acclaimed and is now available in
An epidemiologist, Angus joined a team working to              several languages.                                                        ‘CATCHING A
better diagnose, track and manage stock diseases in both            “The books are designed to be easily understood                      GLIMPSE OF
Thailand and Australia.                                        and practical. I tried to distil key information, offer
     Animal health officers need accurate information on         relevant examples and illustrations. One of my greatest                   THE LIVES
the diseases, their spread and their impact to ensure the      satisfactions is seeing the completed translations (for                   OF THESE
effectiveness of the control programs that are in place.        instance in Spanish, Japanese, Lao and Indonesian),
     During his time in Thailand, Angus worked on new          with much of the work done voluntarily by enthusiastic
                                                                                                                                         FARMERS
epidemiological techniques suited to developing countries.     epidemiologists in different countries.”                                   WAS A
This included developing practical, more affordable survey           The FAO has adopted it as a reference publication.
techniques that are appropriate for Thailand and other              Today Angus is a director of AusVet Animal Health
                                                                                                                                         PRIVILEGE.’
developing countries.                                          Services, a specialist epidemiology consulting company,
     Angus recalls the challenges and rewards of working       providing services to clients in Australia and internationally,
in Thailand at the time: “I was often astounded by the         working across a wide range of species, including livestock,
remoteness and beauty of villages that we surveyed. Catching   aquatic animals, wildlife, plant and human health.
a glimpse of the lives of these farmers was a privilege, and        Angus continues to be involved with disease control
their hospitality at times overwhelming – too much of the      authorities in South-East Asia. He has recently been
local rice whiskey at lunchtime makes it difficult to collect    working with the Thai Department of Fisheries on a
blood from angry buffaloes in the afternoon.”                   surveillance system for Thailand using the Toolbox as a
     He then moved on to Laos to take up a second posting      resource, and in the Philippines conducting training on
with the OSB. His research led to the awarding of a PhD        foot and mouth disease control and surveillance, again
from the University of Queensland.                             using the Toolbox.

SEPTEMBER 2004                                                                19                                          PARTNERS in Research for Development

				
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Description: Solving the mystery of what tick-borne