Leishmaniosis in dogs
Hello lovely people, hope you've all had a wonderful week. As I promised I'm doing a post about leishmaniosis in dogs, all of the information is from the journal "In Practice" the Feb 2019. I'm just going to overview the article then at the end do a little life update as always. I hope you enjoy reading this.
Canine leishmaniosis (CanL) is caused by a protozoan parasite. It's endemic in 70 countries, including the Mediterranean basin. It is also a problem in non-endemic countries as it poses a risk to to public health and veterinary health. This is something that we've been learning about recently, One Health, which is about looking after the public, veterinary and environmental science health. Dogs are the main reservoirs for the human strain and in humans the infection can be fatal if untreated. Dogs can develop both cutaneous and visceral forms if untreated, in which case they can die or are euthanized due to renal disease.
In endemic areas the infection rates of CanL are 70-90% which can be seen by PCR and serology, the higher % is found in Marseilles and throughout Greece and Naples in Italy. In south-western Europe there are 2.5 million dogs infected, and it is spreading to non-endemic areas due to large numbers of travelling dogs.
the parasite completes its life-cycle in two hosts, first is the sandfly vector which has the promastigote form, this then goes to the mammal vectors where the amastigote form replicates inside the macrophages of the current host. Female sandflies are the main vectors of CanL, the other methods of transmission are, in utero, from dam to offspring, venereal from infected dogs to bitches and also blood donors can transmit it.
The parthenogenesis and clinical signs, the clinical signs and underlying pathology are intrinsically related, it has three general pathogenic features;
Canine leishmaniosis (CanL) is caused by a protozoan parasite. It's endemic in 70 countries, including the Mediterranean basin. It is also a problem in non-endemic countries as it poses a risk to to public health and veterinary health. This is something that we've been learning about recently, One Health, which is about looking after the public, veterinary and environmental science health. Dogs are the main reservoirs for the human strain and in humans the infection can be fatal if untreated. Dogs can develop both cutaneous and visceral forms if untreated, in which case they can die or are euthanized due to renal disease.
In endemic areas the infection rates of CanL are 70-90% which can be seen by PCR and serology, the higher % is found in Marseilles and throughout Greece and Naples in Italy. In south-western Europe there are 2.5 million dogs infected, and it is spreading to non-endemic areas due to large numbers of travelling dogs.
the parasite completes its life-cycle in two hosts, first is the sandfly vector which has the promastigote form, this then goes to the mammal vectors where the amastigote form replicates inside the macrophages of the current host. Female sandflies are the main vectors of CanL, the other methods of transmission are, in utero, from dam to offspring, venereal from infected dogs to bitches and also blood donors can transmit it.
The parthenogenesis and clinical signs, the clinical signs and underlying pathology are intrinsically related, it has three general pathogenic features;
- It replicates in the macrophages.
- The infection and development depends on how the hosts immunological responded.
- The infection usually persists in tissues.
The CanL tends to pool in tissues where monocytic-macrophagic cells are in high numbers. the Dog that responds with a T cell-mediated immunity will be asymptomatic but dogs that respond with a humoral immunity will show clinical signs, this isn't set in stone as immunosupressive conditions can change things. It has a prolonged incubation period of 3 months to 7 years which explains the inconsistent change from resistant to susceptible state. Genetics really come in to play with CanL as there are some breeds of dogs who are considered more susceptible like boxers, cocker spaniels, rottweilers and German shepherds. Whereas Ibizan hounds are considered resistant due to the immune response they have. Age also seems to be an important factor with the susceptible age ranges being in young dogs and in older dogs. It can involved any organ and has many clinical signs, renal disease is considered the main cause of death in most clinical cases of CanL. Skin lesions occur in 80-90% cases, along with alopecia around the face, ears and limbs, plus different forms of dermatitis. Ocular lesions can also occur, from conjunctivitis to glaucoma. There are also signs to haemorrhagic diathesis, which can lead to in severe cases anaemia due to uncontrollable blood loss.
The diagnosis; this is complex due to the wide range of clinical signs, and the high rate of subclinical infection. It is important to test healthy dogs in endemic areas, and in non-endemic to try and minimise the spread of the disease. When doing investigative diagnosing it is important to take in the signalment, history and clinical findings and the results of blood or urine tests.
The diagnostic techniques included are; parasitology, molecular and serological. The histology includes things like PCR on bone marrow, it has a high sensitivity and specificity. The serology can be used to detect the antibodies, this can be done by indirect fluorescent antibody tests IFAT and ELISA tests, the IFAT is considered a reference test for the antibodies in dogs. The immunochromatographic rapid in-house test have a high enough specificity, but sensitivity is low at 30-70%, the lowest is when the dogs show no clinical signs. There are a few other methods I've not really explained but they're complicated so if you would like to read up more on them please read the full article.
Therapy and follow up; in order to stop CanL coming back anti-parasitic drugs are given for the time period between months and years, beyond apparent clinical cure. The drugs can be stopped when;
- complete clinical recovery
- clinicopathological normalisation
- antibody levels negative or below the test's cut-off level
finally the prevention, there are two main methods;
- vector control through the use of insect repellent to avoid infectious bites.
- chemotherapeutic and/or immunological control using leishmanicidal drugs and vaccines.
That is all I have for you guys today, WOW it was a real struggle writing this, my brain is slightly frazzled to say the last, having had 20 contact hours this week and 8 training sessions for rowing, it's safe to say I'm dead. But oh well, tomorrow is a new week and I hope that you all have an amazing week, the next time I post I'll by 20 !!!!!!!!!. So have a great week and remember to smile because you never know it could make someones day :)
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