Page 9 - Clinical Connections - Spring 2024

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Page 9 - Clinical Connections - Spring 2024
P. 9

Pathology
        WHAT IS WRONG WITH MY BACKYARD
        CHICKENS?


        Sonja Jeckel, Senior Lecturer in Farm Animal Disease Diagnostics

              eeping  backyard  chickens  is
              popular  in  the  UK and numbers
        K are presumed to have consistently
        increased over the last 20 years. However,
        precise numbers are unknown as only flocks
        with more than 50 animals are obliged to be
        registered with the Animal and Plant Health
        Agency (AHPA).
          Though the general understanding
        of  diseases  in  backyard  chickens  has   Figures 2a and 2b: Infectious laryngitis (ILT) in a chicken. The laryngeal opening is blocked by a
        increased among vets in general practice   large plug of necrotic tissue extending into the trachea
        (to fulfil the needs of their clients), specific
        disease diagnostics in backyard chickens   Investigations               of caseous necrotic material blocking
        remains  challenging  due  to  limited  testing   Examples of PME investigations done by   the  laryngeal  opening.  Histopathology
        options and potentially high associated   us include confirmation of Marek’s disease,   frequently  allows  for  confirmed  diagnosis
        costs.                              one  of  the  more  common  and  serious   by  detecting  herpesviral  inclusion  bodies
          Investigating  a  disease  problem  in  a   diseases in backyard chickens. In some of   in  the  tracheal  epithelium.  The  confirmed
        backyard chicken may be an indicator   these cases, Marek’s disease was clinically   diagnosis  is  significant  for  the  remaining
        of  a  process  affecting  other  birds  in  the   suspected  by  the  submitting  vet,  as  the   flock with regards to recommendations on
        small  flock.  Therefore,  some  owners  are   chickens presented with neurological clinical   vaccinations and new bird introduction.
        keen to reach a diagnosis and assess the   signs.  Confirmation  by  PME  was  sought   However, not all of our PME cases in
        significance of the disease process for the   due to the potential significant implications   backyard chickens have wider implications
        remaining  flock,  even  after  the  individual   for the flock. In other cases, chickens just   – and most owners and submitting vets are
        bird affected has passed away.      presented with progressive loss of condition   a lot happier and relieved about diagnoses
          In such follow-up investigations, the RVC   and the cause of the demise was unclear at   like  egg  peritonitis  or  adenocarcinoma
        Farm  Animal Pathology and Diagnostics   submission.                    without any indication for additional
        Services  (RVC-FAPD)  supports  vets                                    underlying serious disease. Even in some of
        in  practice  by  providing  a  cost-efficient                          these cases there may be some incidental
        specialised  post  mortem  examination                                  findings  that  could  provide  the  submitting
        (PME) service. RVC-FAPD is a partner                                    vet with better insight into the needs of the
        post mortem provider to APHA and as such                                flock, such as the presence of lice, mites or
        PMEs of backyard poultry can be offered at                              nematodes.
        a government subsidised price (currently                                 The  two  main  vets  involved  with  RVC-
        £46 + VAT).                          Figure 1b: Subtle thickening of the left sciatic   FAPD and dissections of backyard chickens
                                             nerve in a chicken due to Marek’s disease  are myself and Dr Bernat Marti-Garcia. We
                                                                                are always interested in discussing any
                                              Some gross PME findings in these cases   potential PME and diagnostic queries in
                                            of Marek’s disease we encountered can be   poultry or other farmed animals with vets.
                                            obvious, with lymphoma in various organs,   You  can  find  further  information,  including
                                            (Fig.1a) but others, including thickening of   our contact details, on the RVC Pathology
                                            nerves, can be more subtle and subjective   and Diagnostic Laboratories web pages.
                                            (Fig. 1b). Histopathology, especially of the   Please note that we cannot accept any
                                            peripheral nerves (sciatic and axillary), was   cadavers of birds suspected of having avian
                                            required to confirm the diagnosis of Marek’s   influenza (or Newcastle disease). In these
                                            disease.                            cases,  you  will  first  have  to  notify  APHA
                                              Another  clinical  example  of  our  (03000 200 301).
                                            investigations  includes  diagnoses  of  If you are dealing with a tricky clinical
                                            infectious  laryngotracheitis  (ILT);  a  case in live backyard chickens, consider
                                            severe, often fatal respiratory disease of   contacting the RVC Exotics Service on
                                            chickens  that  can  affect  several  backyard   exoticscamden@rvc.ac.uk for advice.
                                            chickens  in  a  flock.  Often  these  cases
                                            had been associated with a recent history
                                            of introduction of new birds. PME findings     For the Diagnostic Pathology Service,
         Figure 1a: Markedly enlarged liver with   can be striking (Fig. 2a and b), with plugs   please call:01707 666 208
         multifocal white lymphoma nodules in a                                        Email:
         chicken with Marek’s disease                                                 diagnosticlabs@rvc.ac.uk

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