Project description:The parasite Leishmania siamensis is a zoonotic agent of leishmaniasis; infection in animals has been documented in Europe and the United States. Reported authochthonous human infections have been limited to Thailand. We report a case of human visceral Leishmania siamensis infection acquired in Guyana, suggesting colonization in South America.
Project description:We report the first establishment of in vitro cultivation and genotypic characterization of Leishmania siamensis isolated from an autochthonous disseminated dermal and visceral leishmaniasis in a Thai acquired immunodeficiency syndrome (AIDS) patient. The molecular identification has shown that the parasite was identical to L. siamensis, a recently described Leishmania species reported in the southern provinces of Thailand. The phylogenetic analysis has confirmed L. siamensis as closely related to the zoonotic Leishmania species L. enrietti.
Project description:We report the first case of visceral leishmaniasis caused by Leishmania siamensis in a seronegative child. She was treated with amphotericin B at 1 mg/kg/day for 3 weeks; however, recurrences occurred twice. The patient was cured after the administration of amphotericin B for 5 weeks and monthly prophylaxis for 6 months.
Project description:We report the first case of visceral leishmaniasis (VL) caused by Leishmania martiniquensis in the Caribbean, which until now, was known only to cause cutaneous leishmaniasis. The disease presented with fatigue, anemia, and hepatosplenomegaly in a 61-year-old man with human immunodeficiency virus (HIV) infection who was receiving antiretroviral therapy. Diagnosis was made by bone marrow biopsy. VL is life-threatening, and its emergence in the Caribbean is of concern.
Project description:Leishmania siamensis infection was recently reported from Thailand. Clinical presentation of L. siamensis infections is generally related to human immunodeficiency virus infection. Herein, disseminated dermal L. siamensis infection in a systemic steroid therapy patient from Myanmar is described.
Project description:BackgroundVisceral leishmaniasis (VL) caused by Leishmania siamensis is an emerging disease continuously reported in six southern provinces of Thailand. To date, the phylogenetic relationships among Leishmania isolates from Thai patients and other Leishmania species are still unclear and the taxonomic diversity needs to be established. In this study, the phylogenetic inference trees were constructed based on four genetic loci (i.e., SSU-rRNA, ITS1, hsp70, and cyt b), using DNA sequences obtained from autochthonous VL patients from southern Thailand and reference sequences of reported Leishmania isolates from other studies deposited in GenBank.ResultsPhylogenetic analyses of hsp70 and cyt b loci supported a clade comprised of L. siamensis isolates, which is independent to the other members in the genus Leishmania. In combination with genetic distance analysis, sequence polymorphisms were observed among L. siamensis isolates and two different lineages could be differentiated, lineages PG and TR. Phylogenetic analysis of the cyt b gene further showed that L. siamensis lineage TR is closely related to L. enrietti, a parasite of guinea pigs.ConclusionThe finding of this study sheds further light on the relationships of L. siamensis, both in intra- and inter-species aspects. This information would be useful for further in-depth studies on the biological properties of this important parasite.
Project description:BACKGROUND:Visceral leishmaniasis (VL) is an infectious disease with a variety of clinical signs. The main form of parasite transmission to humans and other mammalian hosts is through the bite of infected arthropod females with Lutzomyia longipalpis serving as the main vector in the Americas. Dogs are the main urban domestic reservoirs of the parasite and the main source of vector infection due to their high prevalence in endemic areas and the large number of parasites in the skin of infected animals. Although miltefosine has been used in Europe since 2002 for treatment of VL infected dogs, in the Americas the treatment of dogs has not been recommended. Therefore, this study aimed to evaluate efficacy of miltefosine observing a reduction of clinical signs in infected dogs and the infectiveness to the vector by Leishmania (L.) infantum. METHODS:To our knowledge, this is the first controlled study using qPCR and xenodiagnosis to evaluate the efficacy of miltefosine (Milteforan®, Virbac) as a single treatment in Brazil. Thirty-five adult dogs with canine visceral leishmaniasis (CVL), confirmed by clinical and laboratory tests, were included in this study. They received miltefosine at a dose of 2 mg/kg every 24 h for 28 days. The dogs were observed over a three-month period, during which clinical evaluations based on a scoring system were conducted at pre-established times. Parasite load was assessed by cytology and real-time polymerase chain reaction (qPCR). Transmissibility to the vector was evaluated by xenodiagnosis. RESULTS:At the end of the period, the following were observed: (i) the remission of clinical signs with a reduction in clinical scores for 94.2% of the animals; (ii) a statistically significant reduction (98.7%) in parasitic load by qPCR; and (iii) a reduction in infectivity to sand flies. After treatment, 74.2% of the animals remained or had become non-infectious. CONCLUSIONS:Our study indicates that the use of miltefosine administered orally for 4 weeks contributes to a clinical improvement and reduction in infectivity of dogs to L. infantum.
Project description:FIve 6/8 week old female BALB/c mice were infected with the LV9 L. donovani strain,five mice were infected with the L. infantum NCL strain, five were uninfected, and spleen and liver were taken from mice at day 36 post infection. These tissues were then used to prepare for RNAseq