Use of Immunotherapy in the Treatment of Canine Visceral Leishmaniasis

Abstract

Background: Canine visceral leishmaniasis is a worldwide zoonosis, with dogs being the main urban reservoirs. It is caused by a protozoan of the genus Leishmania spp. and is transmitted to mammals through a vector belonging to the phlebotomines family. Its treatment aims to reduce the parasitic load preventing these animals from being transmitters. Immunotherapy has been shown to be efficient in stimulating the patient's immune response, improving the general condition and preventing recurrence. This report describes the case of a dog diagnosed with canine visceral leishmaniasis submitted to immunotherapy and drug protocol, noting significant general improvement.Case: An 8-year-old female dog was treated with ulcerated lesions on the paw pads, nasal plane and lip region, onychogryphosis and ungeitis, in addition, hypertrophied popliteal lymph nodes and erosive lesions in the elbows, without improvement with previous treatments. Serological examination was then performed to diagnose leishmaniasis by the immunosorbent assay (ELISA) technique with negative results.  In addition, was performed puncture of the popliteal lymph node, sample in which amastigote forms of Leishmania were observed and blood sample analysis by immunochromatographic rapid test showing reagent result, confirming the diagnosis of canine visceral leishmaniasis. The treatment protocol with marbofloxacin, allopurinol, prednisolone and domperidone was initiated. Thirty days later, there was a total improvement of the lesions and healing of the paw pads. Immunotherapy was then initiated by applying three double doses of recombinant vaccine against canine visceral leishmaniasis. The applications were made subcutaneously, with an interval of 21 days between them, still maintaining allopurinol. After six months a fourth double dose of the vaccine was applied and ten days later a new serological examination was performed using the Indirect Immunofluorescence Reaction (IIFR) technique with total dilution, with the result not reagent. Four months later, the patient was reevaluated and a new serological test was performed through the IIFR technique with total dilution and the result was reagent with high titration (1: 320). Then began the use of milteforan and domperidone. After two months, the patient received a new vaccination booster and the use of domperidone was discontinued. After ten days a new serological examination was performed using the IIIRF technique with total dilution, with reagent result, but with minimal titration (1:40).Discussion: Canine visceral leishmaniasis is a systemic zoonosis of major public health importance. The dog, due to its proximity to humans, is considered the main reservoir of the disease. Although clinical signs are nonspecific, skin lesions such as nasal hyperkeratosis, ulcers and hyperpigmentation, as well as clinical manifestations such as lymphadenopathy, fever, epistaxis and ophthalmic changes are frequently observed. In this case, the patient presented most of the lesions described in the literature. Laboratory abnormalities in blood count and serum biochemistry, commonly observed, were not observed in the animal. The ELISA serological test, despite being used as a screening test, due to its ability to detect low antibody titers, was negative in this case. The diagnosis was confirmed by lymph node cytology, described in the literature as a confirmatory test despite being considered invasive by most authors and positive result in rapid immunochromatography test. With the protocol used, the animal showed improvement, being observed negative results or with low titration of anti-leishmania antibodies in a serological test performed using the IFAT technique, indicating a decrease in parasitic load.