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Canine leishmaniasis (LEESH-ma-NIGH-ah-sis) is a
zoonotic A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a virus, bacterium, parasite, fungi, or prion) that can jump from a non-human vertebrate to a human. When h ...
disease (see human
leishmaniasis Leishmaniasis is a wide array of clinical manifestations caused by protozoal parasites of the Trypanosomatida genus ''Leishmania''. It is generally spread through the bite of Phlebotominae, phlebotomine Sandfly, sandflies, ''Phlebotomus'' an ...
) caused by ''
Leishmania ''Leishmania'' () is a genus of parasitic protozoans, single-celled eukaryotic organisms of the trypanosomatid group that are responsible for the disease leishmaniasis. The parasites are transmitted by sandflies of the genus '' Phlebotomus'' ...
'' parasites transmitted by the bite of an infected phlebotomine
sandfly Sandfly or sand fly is a colloquial name for any species or genus of flying, biting, blood-sucking dipteran (fly) encountered in sandy areas. In the United States, ''sandfly'' may refer to certain horse flies that are also known as "greenhea ...
. There have been no documented cases of leishmaniasis transmission from dogs to humans. Canine leishmaniasis was first identified in Europe in 1903, and in 1940, 40% of all dogs in Rome were determined to be 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, and, as of 2008, ''Leishmania''-positive
foxhound A foxhound is a type of large hunting hound bred for strong hunting instincts, a keen sense of smell, and their barking, energy, drive, and speed. In fox hunting, the foxhound's namesake, packs of foxhounds track quarry, followed—usually on ho ...
s have been reported in 22 U.S. states and two Canadian provinces.Rosypal, Alexa. (2005
Characterization of Canine Leishmaniasis in the United States: Pathogenesis, Immunological Responses, and Transmission of an American Isolate of ''Leishmania infantum''
''Veterinary Clinics of North America Small Animal Practice Journal''. Blacksburg, VA.


Forms and symptoms

Cutaneous *
Alopecia Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Inflammation or scarring ...
* Skin lesions * Ulcerative or exfoliative dermatitis * Interdigital furunculosis(ulcers between toes). Especially if there are other leishmania lesions, such as hair loss, on the same leg. Visceral *
Epistaxis A nosebleed, also known as epistaxis, is an instance of bleeding from the nose. Blood can flow down into the stomach, and cause nausea and vomiting. In more severe cases, blood may come out of both nostrils. Rarely, bleeding may be so significan ...
(nose bleeds) * Kidney failure > increased urination and drinking * Ocular signs * Progressive loss of weight with decreased appetite * Swollen
lymph nodes A lymph node, or lymph gland, is a kidney-shaped Organ (anatomy), organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphoc ...


Cause

Numerous strains and subgenus strains of ''
Leishmania ''Leishmania'' () is a genus of parasitic protozoans, single-celled eukaryotic organisms of the trypanosomatid group that are responsible for the disease leishmaniasis. The parasites are transmitted by sandflies of the genus '' Phlebotomus'' ...
'' exist; with sandfly genome projects still underway, strains are still being discovered. In the
Old World The "Old World" () is a term for Afro-Eurasia coined by Europeans after 1493, when they became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia in the Eastern Hemisphere, previously ...
, leishmaniasis transmitted by sandflies of the genus '' Phlebotomus'' documented in dogs are: * '' L. donovani'' in Sri Lanka * '' L. infantum'' (began appearing dogs in the United States in 2000)
New World The term "New World" is used to describe the majority of lands of Earth's Western Hemisphere, particularly the Americas, and sometimes Oceania."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: ...
leishmaniasis strains are spread by '' Lutzomyia''; however, research speculates the North American sandfly could be capable of spreading, but this is to date unconfirmed. Dogs are known reservoirs of ''L. infantum'', and the spread of disease from dog to dog has been confirmed in the United States. * Suspected causes of canine visceral leishmaniasis are geographic variants of the ''Leishmania donovani'' complex, including ''L. infantum, L. chagasi'' and ''L. donovani''. The Mexicana (''L. mexicana, L. amazonensis, L. venezuelensis'', and ''L. pifanoi'') and Viannia (''L. braziliensis, L. guyanensis, L. panamensis'' and ''L. peruviana'') strains are not commonly found in dogs. Subgenus Viannia strains are found only in Central and South America, all of which cause leishmaniasis in humans.


Transmission

Traditionally, canine transmission is directly from sandfly to dog. Cases in the United States have proven ''L. 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 ''L. infantum'' Mon1 strain found in the United States. Although ''in utero'' transmission is likely the predominant method of disease spread amount the ''L. infantum'' Mon1 strain, it is still a viable parasite (has not lost virulence factors associated with sandfly-uptake) which can be transmitted via sandfly bite. A Brazilian study of 63 puppies from 18 ''L. donovani''-infected parents found no evidence of congential or transplacental infection.


Diagnosis

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 A foxhound is a type of large hunting hound bred for strong hunting instincts, a keen sense of smell, and their barking, energy, drive, and speed. In fox hunting, the foxhound's namesake, packs of foxhounds track quarry, followed—usually on ho ...
and
Neapolitan Mastiff The Neapolitan Mastiff or is an Italian breed of large dog of mastiff type. It was recognised as a breed by the Ente Nazionale della Cinofilia Italiana in 1949, and accepted by the Fédération Cynologique Internationale in 1956. It descends ...
seem to be predisposed or at higher risk for disease. The Italian Spinone Club of America is also requesting all breeders and owners to submit samples for testing; the club reported 150 Spinone Italiano dogs have tested positive in the United States. In the United States, the following veterinary colleges and government bodies assist with testing and treatment of ''Leishmania''-positive dogs: * Centers for Disease Control and Prevention on Leishmaniasis in dogs * Iowa State University Department of Pathology * North Carolina State University College of Veterinary Medicine Diagnostic testing includes molecular biology and genetic techniques which provide high accuracy and high sensitivity/specificity. The most commonly employed methods in medical laboratories include
Enzyme-Linked Immunosorbent Assays The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay is a solid-phase type of enzyme immunoassay (EIA) to detect the presence o ...
, aka ELISA (among other serological assays) and
DNA amplification Gene amplification refers to a number of natural and artificial processes by which the number of copies of a gene is increased "without a proportional increase in other genes". Artificial DNA amplification In research or diagnosis DNA amplificati ...
via Polymerase Chain Reaction ( PCR). The
Polymerase Chain Reaction The polymerase chain reaction (PCR) is a method widely used to make millions to billions of copies of a specific DNA sample rapidly, allowing scientists to amplify a very small sample of DNA (or a part of it) sufficiently to enable detailed st ...
(PCR) method for detecting ''Leishmania'' DNA is a highly sensitive and specific test, producing accurate results in a relatively short amount of time. A study completed in which Foxhounds were tested using PCR showed that approximately 20% of the tested dogs were positive for leishmaniasis; the same population tested with serological/antibody assays showed only 5% positive. Diagnosis can be complicated by false positives caused by the leptospirosis vaccine and false negatives caused by testing methods lacking sufficient sensitivity.


Prevention

In areas where the known vector is a sandfly,
deltamethrin Deltamethrin is a pyrethroid ester insecticide. Deltamethrin plays a key role in controlling malaria vectors, and is used in the manufacture of long-lasting insecticidal mosquito nets; however, resistance of mosquitos and bed bugs to deltamethrin ...
collars worn by the dogs has been proven to be 86% effective. The sandfly is most active at dusk and dawn; keeping dogs indoors during those peak times will help minimize exposure. Unfortunately, there is no one answer for leishmaniasis 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 Pharmaceuticals Inc. was a pharmaceutical company until it was purchased by Pfizer in 2009. The company was founded in Philadelphia, Pennsylvania, in 1860 as John Wyeth and Brother. Its headquarters moved to Collegeville, Pennsylvania, a ...
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, warned since vaccinated dogs develop antibodies, they can be difficult to distinguish from asymptomatic, infected dogs. Studies also indicate the Leshmune vaccine may be reliable in treating ''L. chagasi'', and a possible treatment for dogs already infected with ''L. donovani''. Vaccination and immunotherapy may also be a treatment for ongoing ''L. infantum'' infection in dogs.


Treatment

Currently, no cure exists for canine leishmaniasis, but various treatment options are available in different countries. Treatment is best coordinated with veterinary research hospitals. Treatment does vary by geographic area, strain of infection and exhibited symptoms. Dogs can be asymptomatic for years. Most common treatments include: ''L. donovani'' * Amphotericin B is recommended,
antimony Antimony is a chemical element; it has chemical symbol, symbol Sb () and atomic number 51. A lustrous grey metal or metalloid, it is found in nature mainly as the sulfide mineral stibnite (). Antimony compounds have been known since ancient t ...
resistant ''L. infantum'' *
Amphotericin B Amphotericin B is an antifungal medication used for serious fungal infections and leishmaniasis. The fungal infections it is used to treat include mucormycosis, aspergillosis, blastomycosis, candidiasis, coccidioidomycosis, and cryptococ ...
* Meglumine antimoniate *
Miltefosine Miltefosine, sold under the trade name Impavido among others, is a medication mainly used to treat leishmaniasis and free-living amoeba infections such as '' Naegleria fowleri'' and '' Balamuthia mandrillaris''. This includes the three forms of ...
*
Allopurinol Allopurinol is a medication used to decrease hyperuricemia, high blood uric acid levels. It is specifically used to prevent gout, prevent specific types of kidney stones and for the high uric acid levels that can occur with chemotherapy. It i ...
*
Domperidone Domperidone, sold under the brand name Motilium among others, is a dopamine antagonist medication which is used to treat nausea and vomiting and certain gastrointestinal problems like gastroparesis (delayed gastric emptying). It raises the ...


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. * Foxhound submissions forms * Neapolitan Mastiff submission forms Also in the United States, the CDC is monitoring Italian Spinones, with no end date indicated on sample submissions.


See also

* Dogs portal


References


External links


The Canine Leishmaniasis Site by Vetstream


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Overview of Canine Leishmaniasis


* ttp://www.leishvet.org/fact-sheet/ Guidelines for practising veterinarians {{DEFAULTSORT:Canine Leishmaniasis
Leishmaniasis Leishmaniasis is a wide array of clinical manifestations caused by protozoal parasites of the Trypanosomatida genus ''Leishmania''. It is generally spread through the bite of Phlebotominae, phlebotomine Sandfly, sandflies, ''Phlebotomus'' an ...
Insect-borne diseases Leishmaniasis