Canine Leishmaniasis
Encyclopedia
Canine leishmaniasis is a zoonotic disease (see human leishmaniasis
Leishmaniasis
Leishmaniasis is a disease caused by protozoan parasites that belong to the genus Leishmania and is transmitted by the bite of certain species of sand fly...

) caused by Leishmania
Leishmania
Leishmania is a genus of Trypanosomatid protozoa, and is the parasite responsible for the disease leishmaniasis. It is spread through sandflies of the genus Phlebotomus in the Old World, and of the genus Lutzomyia in the New World. Their primary hosts are vertebrates; Leishmania commonly infects...

 parasites transmitted by the bite of an infected Phlebotomine sandfly. Canine leishmaniasis was first identified in Europe in 1903, and in 1940 it was determined that 40% of all dogs in Rome were positive for leishmaniasis. Traditionally thought of as a disease only found near the Mediterranean basin, 2008 research claims new findings are evidence that canine leishmaniasis is currently expanding in continental climate areas of northwestern Italy, far from the recognized disease-endemic areas along the Mediterranean coasts. Cases of leishmaniasis began appearing in North America in 2000, Leishmania-positive Foxhound
Foxhound
A foxhound is a type of large hunting hound. Foxhounds hunt in packs and, like all scent hounds, have a strong sense of smell. They are used in hunts for foxes, hence the name. When out hunting they are followed usually on horseback and will travel several miles to catch their target. These dogs...

s have been reported in 22 states and 2 provinces of Canada as of 2008.

Forms and Symptoms of Canine Leishmaniasis


Cutaneous
  • Skin Lesions
  • Alopecia
  • Ulcerative or exfoliative dermatitis

Visceral
  • Swollen lymphnodes
  • Ocular signs
  • Progressive loss of weight with decreased appetite
  • Epistaxis (nose bleeds)
  • Kidney failure > increased urination and drinking

Known Strains

Numerous strains and subgenus strains of Leishmania
Leishmania
Leishmania is a genus of Trypanosomatid protozoa, and is the parasite responsible for the disease leishmaniasis. It is spread through sandflies of the genus Phlebotomus in the Old World, and of the genus Lutzomyia in the New World. Their primary hosts are vertebrates; Leishmania commonly infects...

exist with sandfly genome projects http://www.genome.gov/Pages/Research/Sequencing/SeqProposals/SandFliesSeq.pdf still underway strains are still being discovered.

In the Old World
Old World
The Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....

 the leishmaniasis is transmitted by sandflies of the genus Phlebotomus
Phlebotomus
Phlebotomus is a genus of "sand fly" in the Dipteran family Psychodidae. In the past, they have sometimes been considered to belong in a separate family, Phlebotomidae, but this alternative classification has not gained wide acceptance.-Epidemiology:...

documented in dogs are:
  • L. infantum
    Leishmania infantum
    Leishmania infantum is the causative agent of infantile visceral leishmaniasis in the Mediterranean region of the Old World and in Latin America, where it has been called Leishmania chagasi. It is also an unusual cause of cutaneous leishmaniasis. Wild canids and domestic dogs are the natural...

    (Began appearing dogs in the United States in 2000)
  • L. donovani
    Leishmania donovani
    Leishmania donovani is a species of Leishmania. It is an important cause of visceral leishmaniasis. The reference genome of L. donovani extracted in the south eastern Nepal was published in 2011...

    in Sri Lanka


New World
New World
The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...

 leishmaniasis strains are spread by Lutzomyia
Lutzomyia
Lutzomyia is a genus of "sand flies" in the Psychodidae subfamily Phlebotominae and in the order Diptera. In the New World, Lutzomyia sand flies are responsible for the transmission of leishmaniasis, an important parasitic disease and Carrion's disease. Leishmaniasis is generally transmitted in...

however research speculates that the North American sandfly could be capable of spreading but this is to date un-confirmed. Dogs are known resorvoirs of L.infantum and the spread of disease from dog to dog has been confirmed in the United States.
  • Suspected cause of canine visceral leishmaniasis are geographic variants of the Leishmania donovani complex including:
    • L. infantum and
    • L. Chagasi
    • L. donovani


The Mexicana and Viannia strains are not commonly found in dogs:

Mexicana Strains are
  • L. mexicana,
  • L. amazonensis,
  • L. venezuelensis,
  • L. pifanoi)

subgenus Viannia is found only in Central and South America. Most important species are:
  • L. braziliensis,
  • L. guyanensis,
  • L. panamensis and
  • L. peruviana all of which cause Leishmaniasis in humans.

Transmission

Traditionally canine transmission is directly from Sandfly to Dog. Cases in the United States have proven Leishmania Infantum transmission from dog to dog by direct contamination with blood and secretions as well as transplacentally from an infected bitch to her pups.
This mode of transmission seems to be unique to the Leishmania Infantum Mon1 strain found in the United States, a Brazilian study of 63 puppies from 18 L Donovani infected parents found no evidence of congential or transplacental infection.

See Also Leishmania#Uptake and survival

Diagnosis / Testing

In the United States certain breed clubs are strongly recommending screening for Leishmania especially in imported breeding stock from endemic locations. For reasons yet unidentified The Foxhound
Foxhound
A foxhound is a type of large hunting hound. Foxhounds hunt in packs and, like all scent hounds, have a strong sense of smell. They are used in hunts for foxes, hence the name. When out hunting they are followed usually on horseback and will travel several miles to catch their target. These dogs...

 and Neapolitan Mastiff
Neapolitan Mastiff
The Neapolitan Mastiff, Italian Mastiff, is a large, ancient dog breed. This massive breed is often used as a guard and defender of family and property due to their protective instincts and their fearsome appearance....

 seem to be predisposed or at higher risk for disease. The Italian Spinone Club of America is also requesting that all breeders and owners submit samples for testing, the club reports that 150 Spinone Italiano
Spinone Italiano
The Spinone Italiano is an Italian dog breed. However, it should be recognized that the Spinone is a unique, indivisable breed and the correct reference is Spinone . It was originally bred as a versatile gun dog. To this day, the breed still masters that purpose...

 have tested positive in the United States.

In the United States the following veterinary colleges & government bodies assist with testing and treatment of Leishmania positive dogs:
  • Iowa State University Dept of Pathology
  • North Carolina
  • Center for Disease Control


The PCR method for the detection of Leishmania DNA, currently used by Dr. Christina Peterson http://www.vetmed.iastate.edu/faculty_staff/profiles/kalicat.asp is the most sensitive and accurate method for detecting Leishmania. A study completed on Foxhounds (link) whom were tested with PCR showed approximately 20% of the tested dogs positive, the same population tested with anti-body serology (the traditional testing method in the US) showed only 5% positive.

Diagnosis can be complicated by false positives caused by the Lepto vaccine and false negatives caused by testing methods which lack sufficient sensitivity.

Prevention & Vaccines

In areas where the known vector is a sandfly an deltamethrin
Deltamethrin
Deltamethrin is a pyrethroid ester insecticide.-Usage:Deltamethrin products are among the most popular and widely used insecticides in the world and have become very popular with pest control operators and individuals in the United States in the past five years. This material is a member of one of...

 collars worn by the dog has been proven to be 86% effective. The sandfly is most active at dusk and dawn, keeping your dog indoors during those peak times will help minimize exposure.

Unfortunately, there is no one answer for Leishmania prevention nor will one vaccine cover multiple species. "Different virulence factors have been identified for distinct Leishmania species, and there are profound differences in the immune mechanisms that mediate susceptibility/resistance to infection and in the pathology associated with disease."

In 2003 Fort Dodge Wyeth
Wyeth
Wyeth, formerly one of the companies owned by American Home Products Corporation , was a pharmaceutical company. The company was based in Madison, New Jersey, USA...

 released the Leshmune Vaccine in Brazil for L. donovani (also referred to as kala-azar in Brazil).. Studies indicated up to 87% protection Most common side effects from the vaccine have been noted as anorexia and local swelling.
The president of the Brazil Regional Council of Veterinary Medicine, Marcia Villa warns that since vaccinated dogs develop antibodies they can be difficult to distinguish vaccinated dogs from asymptomatic infected dogs.
Studies are also indicating that the Leshmune vaccine may be reliable in treating L. chagasi and a possible treatment for already infected dogs with L. donovani.

Treatment

Currently there exist no cure for Canine Leishmaniasis, there are various treatment options available in different countries. In the United States all drugs used to treat Canine Leishmaniasis are controlled and regulated by the Center for Disease Control (CDC). Treatment is best coordinated with veterinarian research hospitals and the CDC. Treatment does vary by geographic area, strain of infection and exhibited symptoms. Dogs can be asymptomatic for years. Most common treatments include:







L.infantum
  • Pentavalent antimonials
  • Meglumine antimoniate
    Meglumine antimoniate
    Meglumine antimoniate is a medicine used for treating leishmaniasis. It is manufactured by Aventis and sold as Glucantime in France, and Glucantim in Italy. It belongs to a group of compounds known as the pentavalent antimonials. It is administered by intramuscular injection....

  • Amphotericin B
    Amphotericin B
    Amphotericin B is a polyene antifungal drug, often used intravenously for systemic fungal infections...



L. Donovani
  • Antimonial resistant
  • Polyene antibiotic amphotericin B




Given the recent appearance of L.infantum in the United States and the absence of a known vector the CDC recommends euthanasia of infected dogs due to their concerns of spreading the disease and its zoonotic nature. To date no known cases of dog to human transmission have occurred in the United States.

Research Directions

In the United States, research examining the Foxhound and Neapolitan Mastiff is scheduled to continue into 2011 at the University of Iowa. The goals of this project are to screen for the presence of the Leishmania parasite DNA and to be a stepping stone to future research of T-Cell function with the hopes of understanding canine Leishmaniasis as a model for better understanding human Leishmaniasis.
  • Neapolitan Mastiff Submission forms
  • Foxhound Submissions forms


Also in the United States the CDC is monitoring Italian Spinones with no end date indicated on sample submissions.

External links

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