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AN UNEXPLAINED OUTBREAK OF LEISHMANIASIS IN DOGS IN THE USA

First broadcast on www.provet.co.uk  


This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

One of the consequences of increased movement of people and animals around the world is the global transportation of diseases

Leishmaniasis is a potentially fatal disease in both animals and humans. It is caused by an infectious protozoan parasite that is  found in Mediterranean and Tropical countries and it is usually transmitted by the bite of a sandfly. Until recently cases were only thought to occur in non-Tropical countries when the infection was carried back by travelling animals or people.

In 1999  a mysterious disease started to kill fox hounds in the USA and subsequent laboratory investigations showed the cause to be Leishmaniasis. What was unusual about this outbreak was that the dogs themselves had not travelled to an area in which the disease was present, and to this date the origin of the infection has not been found. 

Blood tests have since confirmed that about 12% of fox hounds in 29 states of North America, and in one State (Ontario) in Canada have been exposed to the parasite, and yet tests on other pet dogs and wildlife in the same areas have proved to be negative. Also, no in-contact humans have so far developed signs of the disease.

Whilst the cause of the outbreak has yet to be determined infected dogs have to be regarded as a risk for humans (because Leishmaniasis is a zoonosis), and control measures need to be put in place. 

Leishmaniasis is one of a group of diseases being seen with increasing frequency in the UK - usually in imported dogs that have been to Europe - where the carrier sandflies are found.

Signs of Leishmaniasis in dogs include :

  • Weakness
  • Weight loss
  • Depression
  • Inappetance
  • Gastrointestinal signs - vomiting and diarrhoea
  • Skin disease
  • Swollen legs and joints
  • Respiratory signs - pneumonia, cough
  • Jaundice
  • Fever
  • Death

However, some dogs can be in contact with the organism and develop antibodies and resistance without showing any signs of disease.

In humans the disease causes various signs including :

  • Fever
  • Inappetance
  • Diarrhoea
  • Discolouration of the skin (hands and feet)
  • Death

In humans satisfactory treatment is generally available, but dogs often do not respond so well - especially if they develop renal failure. Unfortunately there are no vaccines against this disease at this time.

The emergence of "new" diseases such as Leishmaniasis is a matter of great concern to veterinarians all over the World, not least because they now have to be aware about a whole spectrum of disease that previously did not occur in their geographical locality.

If your pet becomes ill after it has travelled abroad or after being in contact with another animal or person who has travelled abroad don't forget to tell your vet....it could help him (or her) to make an early diagnosis.

 

Updated October 2013