Along with the increased popularity of backyard chickens more and more owners are keeping ducks and geese. We commonly view waterfowl as bulletproof, and whilst waterfowl are certainly much more resilient than chickens, once they become ill the outcome tends to be bleak.
Respiratory Disease in Ducks
Most often respiratory disease in ducks and geese is caused by a bacteria called Riemerella anatapestifer. The infection is spread either through inhalation or through scarification of their feet. Once the bacteria gains entry a bacteraemia ensues leading to meningitis, synovitis, salphingitis and the sinusitis and air sacculitis. The infection of the oviduct (salphingitis) can mean that it loses patency resulting in internal laying.
Although the eggs will be absorbed, they are often laid faster than the absorption rate, so egg yolks will build up in their abdomen. This can lead to dyspnoea causing affected birds to adopt an upright penguin-like stance to take pressure off their respiratory system. Once birds begin to lay internally the egg mass in the abdomen becomes easily infected and can go on to cause peritonitis.
The susceptibility is age related with the disease commonly affecting ducklings rather than older birds which are less vulnerable.
Owners and vets should look out for:
- Naso-occular discharge
Diagnosis is based upon bacterial culture or by PCR- the VLA or Sci-tec laboratories can carry these tests out for you.
Most vets generally use amoxicillin for five days either orally or by injection- Amoxicillin/clavulanate at 125mg/Kg can be given off label successfully. However it is important to note that many ducklings fail to recover and those that do survive may have stunted growth.
If a duck becomes an internal layer as with chickens antimicrobial therapy combined with a suprelorin implant can help.
Once on a site it is hard to get rid of the bacteria.
Owners can reduce the chances of infection through keeping the house, run and pond as clean as possible (this is not easy as ducks are experts at making a mess). In theory a vaccine could be used, however there is not one currently licensed in the UK. In extreme cases a vaccine can be imported using an SIC.
Diarrhoea in Ducks and Geese
Just as for chickens there are several possible causes of diarrhoea in waterfowl detailed below.
As for chickens poor quality feed or excessive/inappropriate treats can lead to diarrhoea. Note: Waterfowl should be fed waterfowl feed - not hen or turkey feed.
Worms in Ducks and Geese
Just as for chickens there are several species of worms which can infect both ducks and geese.
There is a species of worm which is related to ‘gape worms’ which can live in the trachea of water fowl causing gaping, however this is relatively uncommon. However as with chickens gastrointestinal worms are much more common and important. Capillaria (Hairworms) are highly important in young goslings.
Clinical Signs include:
- weight loss
- poor growth
- lack of egg production
- mild diarrhoea
As with chickens faecal worm egg counts can be used but in goslings hairworms can lead to clinical signs before the worms become fecund meaning any gosling with any signs of hairworms should be treated irrespective of whether or not worm eggs are seen upon faecal examination.
Flubenvet is licensed for use in geese and although it is not licensed for use in ducks it can safely be given to duck at the goose dose rate.
Routine worming every 3 months with Flubenvet as with other poultry is recommended. For goslings and geese in general pasture rotation is highly recommended.
Duck Viral Hepatitis
Duck viral hepatitis is a disease caused by one of three viruses (astrovirus, enterovirus or picoronavirus) that affects the livers of young ducklings up to 7 weeks of age. Once the disease enters a group of ducklings it will spread rapidly.
Infection leads to :
- sudden death (up to 100% mortality)
Diagnosis can only be made by a post mortem looking for ecchymotic haemorrhages of the liver. Occasionally the spleen will be enlarged and mottled. Suspected cases can be confirmed by either histopathology or virus isolation.
Antibiotic treatment may be attempted with Amoxicillin though in many cases the prognosis is very poor. Prevention
Good hygiene and a reduction in stress will help reduce the likelihood of this disease occurring. A vaccine is available in some parts of the world but unfortunately not in the UK. If necessary a vaccine can be imported using an SIC.
Duck Viral Enteritis
Duck viral enteritis (DVE) is caused by a herpes virus infection of waterfowl. The virus is typical of herpes viruses in that it becomes latent in the trigeminal nerve. During the stress of the breeding season, wild migrating birds will shed the virus in their faeces leading to infection via the faeco-oral route and through cloacal uptake from contaminated water. This gives the disease a seasonal occurrence usually from April-June.
What to look out for:
- sudden death often in April-June (Due to migration of wild birds)
- wing walking
- naso-occular discharge
- haemorrhagic diarrhoea
Diagnosis is based upon clinical signs, the time of year and of post mortem lesions which include: haemorrhages throughout the body (due to vascular damage), thymic oedema, inflammation of the gut associated lymphoid tissue, diptheresis of the oesophagus and vent and necrosis and haemorrhage of the intestine. Confirmation through PCR or virus isolation can be carried out.
Figure 1: The inflamed intestinal mucosa of a duckling with DVE
Treatment is based upon supportive care but the prognosis is poor. Remember that survivors will become latently infected.
Prevention is primarily based upon keeping wild waterfowl away. There are currently no licensed vaccines in the UK but they are available in other countries and these can be imported under an SIC where necessary.
Goose Parvovirus (Derzsy’s disease, Goose/Gosling Plague)
Parvoviruses can infect both Muscovy ducks and geese with similarly devastating effects to those found with canine parvovirus. The virus is spread predominantly vertically. This can initially cause poor hatchability.
What to look out for:
Birds under one week of age show: difficulty breathing, inappetance, weight loss and almost certainly die.
Birds from one week up to one month will often have: diarrhoea, weight loss, naso-occular discharge, ascities, conjunctival swelling, a diphtheritic oral membrane, and neurological signs.
Older birds tend not to show clinical signs.
Diagnosis is based upon clinical signs in young goslings and Muscovy ducklings. Post mortem findings can be suggestive of parvovirus infection. These include hepatosplenomegaly, palour and enlargement of the heart, pericarditis, pulmonary oedema, pancreatic enlargement, perihepatitis, ascities and a catarrhal enteritis. Histopathology looking for intranuclear inclusion bodies can help support the diagnosis. Virus isolation can be used to confirm clinical suspicion.
Treatment may be attempted in mild cases using fluid therapy and potentially antimicrobials to control secondary infection but ultimately treatment outcomes age dependent. Remember the infection is highly infectious and this will be a flock problem.
Prevention includes good hygiene and biosecurity. Vaccination of breeding stock can effectively control infection in their offspring through maternally derived antibodies.