Frequency, active infection and load of Leishmania infantum and associated histological alterations in the genital tract of male and female dogs

Unexpected Cytological Detection of Leishmania infantum within the Secretion of a Canine Mammary Carcinoma

Mammary tumors are one of the most common neoplasms in female dogs, and cytology represents a non-invasive diagnostic method. The protozoal pathogen Leishmania spp. was previously demonstrated in canine mammary glands. An eight-year-old, female-spayed Doberman was imported from Crete, Greece, three years before the first presentation. The dog was presented due to a mammary tumor two years after adoption. The clinical examination revealed fever and weight loss. Smears of the mammary secretion were investigated cytologically. Multiple atypical epithelial cells with moderate to marked criteria of malignancy were detected. Furthermore, amastigotes were visible intra- and extracellularly. The diagnosis of L. infantum infection was based on a positive PCR out of the cytological smear, and a positive serology. Mammary carcinoma and granulomatous inflammation with amastigotes were confirmed by histopathology. We aimed to provide a complete report of cytological, histopathological, hematological, and biochemistry findings in a dog with L. infantum in the mammary glands with focus on trans-mammary pathogen transmission as a potential alternative way of spreading Leishmania infections. Canine leishmaniasis should be a potential differential diagnosis in dogs with lesions and/or inflammation in the mammary glands and a history of presence in areas endemic for L. infantum, especially the Mediterranean in Europe.

Field-Deployable Treatments For Leishmaniasis: Intrinsic Challenges, Recent Developments and Next Steps

Leishmaniasis is a neglected tropical disease endemic primarily to low- and middle-income countries, for which there has been inadequate development of affordable, safe, and efficacious therapies. Clinical manifestations of leishmaniasis range from self-healing skin lesions to lethal visceral infection with chances of relapse. Although treatments are available, secondary effects limit their use outside the clinic and negatively impact the quality of life of patients in endemic areas. Other non-medicinal treatments, such as thermotherapies, are limited to use in patients with cutaneous leishmaniasis but not with visceral infection. Recent studies shed light to mechanisms through which Leishmania can persist by hiding in cellular safe havens, even after chemotherapies. This review focuses on exploring the cellular niches that Leishmania parasites may be leveraging to persist within the host. Also, the cellular, metabolic, and molecular implications of Leishmania infection and how those could be targeted for therapeutic purposes are discussed. Other therapies, such as those developed against cancer or for manipulation of the ferroptosis pathway, are proposed as possible treatments against leishmaniasis due to their mechanisms of action. In particular, treatments that target hematopoietic stem cells and monocytes, which have recently been found to be necessary components to sustain the infection and provide a safe niche for the parasites are discussed in this review as potential field-deployable treatments against leishmaniasis.

Report of the presence of Leishmania infantum in the milk of a naturally infected female dog in Brazil

Dogs are the most important reservoir of Leishmania infantum, the causal agent of visceral leishmaniasis in Brazil. Although lymphoid tissue is the most important biological tissue where amastigotes can be found, this paper describes the presence of L. infantum DNA in the milk of a lactating naturally infected female dog. This finding suggests the need for further studies to elucidate whether breastfeeding can be a route of infection.

Molecular detection of vector-borne pathogens in semen from dogs in southeastern Brazil

Vector-borne pathogens (VBPs) are primarily transmitted by arthropod vectors, but secondary ways of transmission have been described, including via venereal route. Nonetheless, there is still limited research on possible sexual transmission of VBPs in dogs. We molecularly investigated the presence of vector-borne pathogens in semen from dogs living in an area where these agents are endemic. Upon PCR testing, seven out of 22 (31.8%) semen samples tested positive for at least one VBP, whereas simultaneous positivity to two or more pathogens was detected in three (13.6%) dogs. Among pathogens detected in semen, Trypanosoma cruzi (n = 1) and Leishmania infantum (n = 3) were identified to species level by restriction fragment length polymorphism analysis. Attempts to sequence PCR products from other pathogens were unsuccessful, but coupled epidemiological and molecular data suggest the presence of Anaplasma platys (n = 5), Babesia vogeli (n = 1) and Ehrlichia canis (n = 1) in semen from dogs. Further experimental studies would be needed to confirm the sexual transmission hypothesis for these VBPs and also the possible implications of these findings for canine reproduction.

Anti-Brucella canis antibodies in dogs naturally infected with Leishmania infantum and associated histological alterations in the genital tract

In canine visceral leishmaniasis, coinfections can aggravate the disease. Our aim was to investigate Brucella canis in dogs infected with Leishmania infantum. One hundred and six L. infantum-seropositive dogs were submitted to serology for B. canis, PCR for B. canis and L. infantum, and histopathological analysis of the genital tract. Anti-B. canis antibodies were detected in seven dogs whose clinical signs, L. infantum load and histological alterations were similar to those of seronegative animals. The circulation of anti-B. canis antibodies was low but demonstrates the exposure of dogs to this bacterium in a visceral leishmaniasis-endemic area.