Leishmaniasis: All You Should Know – Part II

Introduction to the Series

Important Note: I’ve done my best to keep this post informative and accurate. Be aware that I am neither a doctor, a veterinarian, nor a biologist, and that my knowledge of biology and medicine is limited to what I learnt in high school and what I may have picked up along the way since then. Before trying anything on your dog or if in doubt, check with your vet. If you spot any mistakes, please let me know by leaving a comment or contacting me through any social networks.

If you’ve been following the blog for a while, you may know that one of my dogs, Syd, was diagnosed with Leishmaniasis (or Leishmaniosis) at four years of age. Although she survived the disease, it certainly made the remainder of her life much more complicated.

Since there have been several advances on the topic since then, I decided to do some research and write  comprehensively about it. I considered writing just one post, but it would be very long, and I think it’s better to digest the information in stages. These are the points that I will be covering (the list will be expanded as posts are published):

Feel free to jump to the post or section that interests you the most.

Transmission of Leishmaniasis

As I explained earlier, the main mechanism of transmission of the disease is through the sandfly bite. This section examines further ways in which the disease may be transmitted, both between dogs and between dogs and people.

Transmission between Dogs

Apart from the sandfly bite, there are other ways in which leishmaniasis can be transmitted between dogs:

  • Horizontal transmission, that is, from one infected dog to a non-infected one. This may happen in several ways:
    • Direct contact with infected cells in blood (Petersen and Barr 2009)
    • Venereal, especially from the male to the female. The other way around seems less likely.
  • Vertical transmission, that is, from mother to litter (Petersen and Barr 2009).

More research needs to be done, though, to find out the likelihood of these other forms of transmission and if others are possible (such as by means of a dog bite).

Syd on a day she was not very well. Although she was diagnosed at 4, I still wonder whether she got the disease from her mother.

Transmission Between Dogs and People

The transmission risk may increase between infected dogs and people suffering from immunosuppressive conditions (HIV, AIDS), as they have lower body defenses against outside agents. It is important to note, though, that generalized infection of dogs in an area does not directly imply a higher rate of incidence in people (Otranto and Dantas-Torres 2013).

Bear in mind, also, that some people develop an effective immunological response to leishmaniasis and never show any symptoms (McCall, Zhang, and Matlashewski 2013).

Symptoms in Dogs

Symptoms in dogs are similar to the ones described above. Be aware that dogs will not necessarily show all the symptoms listed below, and that in many instances they may be caused by other issues and not necessarily leishmaniasis.

So, if you suspect that your dog is suffering from the disease, you should make an appointment with your vet and get him to run the appropriate tests.

The symptoms include (Ribeiro et al. 2018; Baneth n.d.):

Notice the lack of hair in Syd’s elbow.
  • Lymphadenopathy (abnormal size of the lymph nodes)
  • Skin lesions
  • Ocular abnormalities
  • Nose bleeding (epistaxis)
  • Abnormal nail growth
  • Weight loss
  • Exercise intolerance
  • Any symptoms related to kidney disease / renal failure, such as (Pet MD n.d.):
    • Changes in the amount of urination
    • Vomiting
    • Lethargy
    • Diarrhoea
    • Constipation
    • Depression
    • Weight loss
    • Lack of appetite
    • Increased thirst
    • Blood in the urine
    • Acute blindness
    • Seizures and comas

Syd’s Symptoms: Our Experience

Although this post is based heavily on research, I thought it was worth explaining our experience with Syd. To begin with, the symptoms were not obvious. She was diagnosed at a routine check-up, after I asked the vet if we should worry about the lack of hair on her elbows. She also had longish nails. However, both the lack of hair and the long nails, can be due to the dog spending a lot of time lying down.

My best advice, then, would be to bring your dog to regular check-ups with your vet, and asking him any questions if you’re ever in doubt.

If you look closely at Syd’s elbow, you will see that some hair is missing. However, this could be due to lying down and not due to leishmaniasis.

References

Baneth, Gad. n.d. “Overview of Leishmaniosis (Visceral Leishmaniasis).” MSD Manual Veterinary Medicine (blog). Accessed September 5, 2018. https://www.msdvetmanual.com/generalized-conditions/leishmaniosis/overview-of-leishmaniosis.

McCall, Laura-Isobel, Wen-Wei Zhang, and Greg Matlashewski. 2013. “Determinants for the Development of Visceral Leishmaniasis Disease.” Edited by Chetan E. Chitnis. PLoS Pathogens 9 (1): e1003053. https://doi.org/10.1371/journal.ppat.1003053.

Otranto, Domenico, and Filipe Dantas-Torres. 2013. “The Prevention of Canine Leishmaniasis and Its Impact on Public Health.” Trends in Parasitology 29 (7): 339–45. https://doi.org/10.1016/j.pt.2013.05.003.

Pet MD. n.d. “Kidney Failure (Long-Term) in Dogs.” Pet MD (blog). Accessed September 5, 2018. https://www.petmd.com/dog/conditions/urinary/c_multi_renal_failure_chronic.

Petersen, Christine A., and Stephen C. Barr. 2009. “Canine Leishmaniasis in North America: Emerging or Newly Recognized?” Veterinary Clinics of North America: Small Animal Practice 39 (6): 1065–74. https://doi.org/10.1016/j.cvsm.2009.06.008.

Ribeiro, Raul Rio, Marilene Suzan Marques Michalick, Manoel Eduardo da Silva, Cristiano Cheim Peixoto dos Santos, Frédéric Jean Georges Frézard, and Sydnei Magno da Silva. 2018. “Canine Leishmaniasis: An Overview of the Current Status and Strategies for Control.” BioMed Research International 2018: 1–12. https://doi.org/10.1155/2018/3296893.

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