Primary hypothyroidism associated with leishmaniasis in a dog

Lymphocytic hypophysitis in dogs infected with Leishmania spp

Background

Morphological involvement of endocrine glands, such as the pituitary gland, remain uninvestigated in dogs with canine visceral leishmaniasis. Therefore, this study investigated the presence of amastigotes of Leishmania spp. and characterized inflammatory changes, highlighting the involvement of TCD3+ lymphocytes in different regions of the pituitary gland of dogs.

Methods

Samples were collected from 21 naturally infected dogs and 5 control, uninfected dogs. The different pituitary regions were analyzed in histological sections stained with hematoxylin and eosin (HE) under light microscopy. Inflammation was classified by intensity in a score from 0 to 3, absent (0), mild (1), moderate (2), and marked (3). The immunohistochemical (IHC) evaluation was performed in five high-power fields (hot spot) in a 40x objective of each region with manual counting (Image J1.52ª) of the TCD3+ lymphocytes and for amastigotes analyzed in 40x and 100x objectives. The Shapiro-Wilk test was used to assess the normality of the data. Differences between groups were determined by the Mann Whitney test. The correlation between variables was assessed by Sperman's correlation test. p < 0.05 were considered statistically significant.

Results

Amastigotes from the pituitary glands of two infected dogs were identified using IHC. The histopathological evaluation stained with hematoxylin and eosin showed greater intensity of inflammation in the pars distalis and pars intermedia regions of infected dogs. IHC for TCD3+ lymphocytes showed a higher median number of immunolabeled cells in pars nervosa in the infected group than in the control group (p < 0.05); and expecting a variation in the distribution and number of these cells in naturally infected dogs, the median of the control group was considered a cut-off point, an increase in T lymphocytes (p < 0.05) was also observed in the pars intermedia and pars distalis of an infected subgroup (n = 10). A moderate significant correlation between the intensity of inflammation and the number of immunolabeled TCD3+ lymphocytes was established in the analyzed pituitary regions, characterizing the occurrence of hypophysitis.

Conclusion

These findings presuppose that inflammation and/or the parasite in the pituitary region can result in gland dysfunction, worsening the clinical condition of the patient and compromising the efficiency of treatment and prognosis.

Canine visceral leishmaniosis: the relationship of blood serum thyroid hormones, lipids, and lipoproteins with clinical status

The objective of the present study was to investigate the role of thyroid hormones and lipid profile in development and outcome of canine visceral leishmaniosis (CVL). We therefore studied the relationships between blood serum thyroid hormones [total T4, free T4, total T3, and free T3], lipids, and lipoproteins [total cholesterol, triglyceride, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C)] and clinical status in dogs naturally infected with Leishmania infantum. Two groups of Leishmania-infected dogs [with no clinical signs (NCS; n = 15), and with clinical signs (CS; n = 16)] were assessed and compared with a group of healthy control dogs (n = 15). A significant decrease in serum total T4 (p < 0.05) concentration in the CS group was observed when compared to the NCS and control groups. The dogs in CS group revealed a significant decrease (p < 0.05) in free T4 concentration in comparison to the control group. The CS group presented a significant decrease in HDL-C (p < 0.01) concentrations, when compared to NCS and control groups. The observed findings in the present study suggested that thyroid hormone and lipoprotein alterations may have a role in susceptibility of dogs with Leishmania infection.

Lesões orais secundárias à leishmaniose visceral em um cão com hiperadrenocorticismo endógeno: relato de caso

RESUMO O objetivo do presente trabalho foi relatar um caso de leishmaniose visceral com apresentação mucosa em um cão com hiperadrenocorticismo. Um canino, macho, da raça Poodle, 11 anos de idade, foi atendido com histórico de disfagia, halitose e sialorreia. Ao exame físico, observou-se linfadenomegalia generalizada e alterações cutâneas, como rarefação pilosa, comedões, telangiectasia e atrofia cutânea. Além disso, o animal também apresentava formações orais localizadas na língua. Dos exames hematológicos e bioquímicos realizados, a única alteração encontrada foi elevação da fosfatase alcalina (1724u/L). O teste de supressão com a dexametasona em dose baixa foi executado para investigar hiperadrenocorticismo, tendo resultado positivo. Também foram realizados exames citológicos dos linfonodos, da medula óssea e das formações orais, tendo sido observada a presença de formas amastigotas de Leishmania sp. em todas as amostras. O animal foi submetido à biópsia incisional das formações orais, e a análise histopatológica demonstrou um quadro de inflamação granulomatosa com presença de grande quantidade de microrganismos morfologicamente compatíveis com formas amastigotas de Leishmania sp. no interior das células inflamatórias. Diante dos achados clínicos e dos exames complementares, diagnosticou-se um caso de leishmaniose com manifestação mucosa atípica, associado ao hiperadrenocorticismo, podendo essa endocrinopatia ter sido um fator predisponente para essa enfermidade infectocontagiosa.

Leishmaniosis of companion animals in Europe: an update

Leishmaniosis caused by Leishmania infantum is a vector-borne zoonotic disease endemic in southern Europe, but which is spreading northwards. Millions of dogs, cats and other non-conventional companion animals susceptible to L. infantum, living in European households, may develop a severe disease and contribute to the spread of leishmaniosis because of travelling or re-homing. Dogs are the main reservoir but other new reservoirs have recently been incriminated. Sand flies remain the sole proven vector and non-vectorial transmission has been reported at individual level and in areas where the vector is absent. Clinical disease affects only a proportion of infected dogs and a complex genetic background of immune response is responsible for this susceptibility. There is a wide range of serological and parasitological diagnostic tools available whose cost-effective use depends on a reasoned approach. Clinical response to treatment of sick dogs is variable. Clinical cure is often obtained but clinical recurrence can occur and post-therapy follow up should be maintained life-long. In Europe, vaccination can be combined with individual protection with pyrethroids as part of an integrated approach to prevention. L. infantum is the only species isolated from cats in Europe and xenodiagnosis substantiated that infected cats are infectious for sand flies. Feline infection may be frequent in endemic areas, but prevalence is generally lower than in dogs. When cats are tested by both serological and molecular techniques discordant results are often observed. Feline cases have been reported from endemic areas in Italy, France, Spain and Portugal, but four cases were also diagnosed in Switzerland in cats that had travelled to or been imported from Spain. Half of the cases were diagnosed in cats with impaired immune responses. Clinical manifestations compatible with feline leishmaniosis include lymph node enlargement, skin and mucocutaneous lesions, ocular lesions, chronic gingivostomatitis, hypergammaglobulinemia, and normocytic normochromic anemia. Cats have been empirically treated with some drugs used in dogs. Due to polymorphic clinical picture and the insidious progressive course, leishmaniosis can persist for a long time before dogs or cats are brought to a veterinarian and so diagnosis can be delayed. Exotic or new Leishmania spp. have been reported in humans, animals and vectors in Europe. This changing situation requires attention in Europe for designing epidemiological studies and control measures.

Pathologic mechanisms underlying the clinical findings in canine leishmaniasis due to Leishmania infantum/chagasi

In dogs with symptomatic or asymptomatic leishmaniasis, Leishmania infantum appears to induce a mixed Th1/Th2 immune response that in the sick dog may eventually result in tissue damage via different pathomechanisms, notably granulomatous inflammation (eg, nodular dermatitis, osteomyelitis), immune complex deposition (eg, glomerulonephritis), and/or autoantibody production (eg, polymyositis). This is a compensatory but detrimental mechanism generated mainly because of the insufficient killing capacity of macrophages against the parasite in the susceptible dog. Clinical disease is typically exemplified as exfoliative and/or ulcerative dermatitis, with or without nasodigital hyperkeratosis and onychogryphosis, glomerulonephritis, atrophic myositis of masticatory muscles, anterior uveitis, keratoconjunctivitis sicca, epistaxis, and/or polyarthritis, appearing alone or in various combinations. The pathogenesis of these clinical conditions has recently been highlighted, to a greater or lesser extent. The usually subclinical conditions expressed as chronic colitis, chronic hepatitis, vasculitis, myocarditis, osteomyelitis, orchiepididymitis, and meningoencephalomyelitis, though uncommon, are of pathologic importance from a differential point of view. The leading cause of death among canine leishmaniasis patients is chronic proteinuric nephritis that may progress to end-stage kidney disease, nephrotic syndrome, and/or systemic hypertension. However, even the asymptomatic proteinuria, when profuse, may be a serious problem because it predisposes to arterial thromboembolism and eventually contributes to the deterioration of the body condition.

Subclinical hypothyroidism in a patient affected by advanced AIDS and visceral leishmaniasis

Hypothyroidism has been shown to occur in HIV disease. Thyroid function of patients affected by AIDS and leishmaniasis is unknown. Here we report the case of an AIDS advanced patient developing hypothyroidism during leishmaniasis. The thyroid disorder might have been caused by infiltration of the gland by Leishmania. An additive impact of HIV in thyroid function impairment is suggested.

Resolution of tongue lesions caused by Leishmania infantum in a dog treated with the association miltefosine-allopurinol

Canine leishmaniosis is a severe systemic disease caused by the kinetoplastid protozoan Leishmania infantum, an obligatory intracellular parasite of mammalian macrophages, transmitted by the bite of phlebotomine sandflies. The infection in dogs might occur without any clinical signs or might be characterised by chronic viscerocutaneous signs, such as lymphadenopathy, skin lesions, splenomegaly, onychogryphosis, and renal as well as ocular damage due to immunocomplex deposition. In atypical cases the parasites can be found in the striated musculature, the central nervous system, the endocrine glands or gonads, with or without functional damage. Leishmania infection might seldom induce oral lesions, particularly on the tongue. The authors describe the clinical case of a four-year old mongrel dog with tongue lesions caused by L. infantum. The dog was presented due to diarrhoea, lack of appetite and hypersalivation. Examination of the oral cavity revealed the presence of multiple red, nodular lesions on the dorsal and lateral surfaces of the tongue. Definite diagnosis of an infection with L. infantum was obtained by an indirect immunofluorescence antibody test (IFAT) and by the cytological identification of the parasite in nodular, lingual lesions and bone marrow aspirates. The dog was treated with a combination of miltefosine (Milteforan^®, Virbac), 2 mg/kg orally once a day for four weeks and allopurinol (Ziloric^®, GlaxoSmithKline), 10 mg/kg orally twice a day for six months. At the end of the treatment, the animal showed full remission of clinical signs. The authors outline the atypical manifestations in the oral cavity in combination with a L. infantum infection and discuss the therapeutic potential of the combination treatment of miltefosine and allopurinol in canine leishmaniosis.

Presence of Leishmania amastigotes in peritoneal fluid of a dog with leishmaniasis from Alagoas, Northeast Brazil

The goal of this short communication is to report the uncommon presence of intracellular amastigotes of Leishmania in peritoneal fluid of a dog with leishmaniasis from Alagoas State, Brazil. Physical examination of an adult male rottweiler suspected to be suffering of leishmaniasis revealed severe loss of weight, ascitis, splenomegaly, moderately enlarged lymph nodes, onychogryphosis, generalized alopecia, skin ulcers on the posterior limbs, and conjunctivitis. Samples of bone marrow, popliteal lymph node, skin ulcer, and peritoneal fluid were collected and smears of each sample were prepared and stained with hematoxylin and eosin. Numerous amastigotes were detected in bone marrow, popliteal lymph node, and skin ulcer smears. Smears of peritoneal fluid revealed the unusual presence of several free and intracellular amastigotes of Leishmania. Future studies are needed to determine whether the cytology of ascitic fluid represents a useful tool for diagnosis Leishmania infection in ascitic dogs, particularly in those living in areas where canine leishmaniasis is enzootic.

Management of leishmanial osteolytic lesions in a hypothyroid dog by partial tarsal arthrodesis

A five-year-old male boxer, previously diagnosed with leishmaniasis and hypothyroidism, had gradually become unable to bear weight on its left hindlimb. Physical examination revealed a left popliteal lymphadenopathy, mild crepitus, and severe swelling of the left tarsal joint, a radiographic examination of which revealed severe bone destruction of the talus and a periosteal reaction of the calcaneus. Laboratory findings and serological tests suggested an active leishmanial infection, and a Leishmania species was identified by direct cytology of a sample from the osteolytic area and by indirect immunohistochemistry of a bone biopsy. The dog's condition improved when it was treated with meglumine antimonate and allopurinol. Because of the large osteolytic area and the increased use of the affected leg, a partial tarsal arthrodesis was performed to prevent a fracture. Five months after the surgery, the osteolytic area had healed completely and the calcaneus periosteal reaction had disappeared.