Autochthonous Outbreak and Expansion of Canine Visceral Leishmaniasis, Uruguay.
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ABSTRACT:
SUBMITTER: Satragno D
PROVIDER: S-EPMC5382754 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:A 12-year-old spayed female mixed-bred dog presented with nasal bleeding of 2 days duration and a skin nodule in the left flank. No abnormalities were found in coagulation profiles and blood pressure. Cytological evaluation of the nodule revealed numerous characteristic round organisms having a nucleus and a bar within macrophages and in the background, consistent with leishmaniasis. In vitro culture was unsuccessful but PCR of the nodular aspirate identified the organisms as Leishmania infantum, and the final diagnosis was canine leishmaniasis. No history of travel to endemic countries was noted. Because the dog had received a blood transfusion 2 years before the illness, serological screening tests were performed in all donor dogs of the commercial blood bank using the commercial Leishmania ELISA test kit, and there were no positive results. Additional 113 dogs with hyperglobulinemia from Seoul were also screened with the same kits but no positive results were obtained. To the best of the author's knowledge this is the first autochthonous case of canine leishmaniasis in Korea.
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Project description:Canine leishmaniasis is a zoonotic disease caused by Leishmania infantum; transmitted by the bite of phlebotomine sand flies. Leishmania infantum amastigotes were identified by cytology from a locally born Hong Kong dog exhibiting nasal, cutaneous, and systemic disease who was part of a kennel of eight dogs. All eight kennel dogs were subsequently tested serologically by enzyme-linked immunosorbent assay (ELISA) and by polymerase chain reaction (PCR) followed by DNA sequencing for L. infantum infection. The local dog was seropositive and blood and splenic tissue were PCR positive for L. infantum whilst the other kennel dogs were negative on serology and PCR. Autochthonous transmission was suspected for the local dog as Hong Kong lacks known vectors of L. infantum. Either vertical transmission from the deceased dam who had previously died with disease suspicious for leishmaniasis or horizontal transmission from a second non-locally born kennel dog who had been diagnosed previously with leishmaniasis was possible. This is the first recorded autochthonous case of canine leishmaniasis in Hong Kong. Leishmaniasis should be considered as a differential for cutaneous or systemic illness in local untraveled dogs in Hong Kong. In addition, as dogs serve as L. infantum reservoirs for human infection attention should be paid to the possibility of leishmaniasis emerging in Hong Kong.
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Project description:Visceral leishmaniasis is the most important zoonosis in Europe and it is caused by Leishmania infantum, a protozoan intracellular parasite. Canine visceral leishmaniasis (CVL) is endemic in the Mediterranean basin, Middle East, and South America, and is emerging within non endemic areas such as the United Kingdom and North America. We have analyzed 24 polymorphisms in the canine Slc11a1 (formerly NRAMP1) gene: 19 new polymorphisms characterized by direct sequencing from 40 dogs of different breeds and five polymorphisms previously described. Data analysis in a case-control study including 164 dogs of 19 different breeds revealed that two of the 24 polymorphisms were associated with increased risk for CVL: one intronic single nucleotide polymorphism (SNP) (A4549G in intron 6: odds ratio (OR) = 6.78, P = 0.001) and one silent SNP in exon 8 (C4859T: OR = 13.44, P = 0.004). In silico analysis of the significant SNP revealed that SNP in the promoter region affect putative transcription binding sites and SNP C4859T in exon 8 disrupts a putative exonic splicing enhancer (ESE). These results corroborate that Slc11a1 polymorphisms are associated with increased risk for CVL.
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Project description:Human visceral leishmaniasis (HVL) is a parasitic disease infecting children in the Mediterranean region. Here, we portray a case of a 2-year-old child with an epidemiological description of the situation surrounding the case. The patient was suffering from recurrent fever, weakness, and abdominal discomfort associated with loss of appetite. Routine blood investigations showed pancytopenia, whereas examination revealed hepatomegaly. A diagnosis of HVL was made by demonstrating amastigotes in a Giemsa-stained smear from a bone marrow aspirate followed by genotyping by PCR and sequencing. In conclusion, early detection of VL infection followed by appropriate treatment protocols is essential to saving the patient.
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Project description:BACKGROUND:Visceral leishmaniasis (VL) is caused by protozoa of the Leishmania donovani complex. Annually, an estimated 500,000 cases of VL are reported globally posing a public health challenge. The objectives of our study were to confirm and determine the magnitude of VL outbreak, characterize the outbreak clinically and epidemiologically and evaluate the county preparedness and response in Marsabit County, Kenya. METHODS:A retrospective review of laboratory registers and patients' clinical notes was done at Marsabit County Hospital. Cases were persons with confirmed VL diagnosis either by microscopy, serology or molecular technique coming from Marsabit County from May to October 2014. Cases were interviewed using structured questionnaire to collect clinical and epidemiologic information. Blood samples were collected from cases for laboratory confirmation. RESULTS:A total of 136 cases were confirmed of which 77% (105) were male with a median age of 17 (IQR: 22) years and 9.6% (13) case fatality rate. All cases were admitted at Marsabit County Referral Hospital, Kenya. Medical records of 133 cases were retrieved. Of the 133 cases, 102 (77%) presented with fever, 43 (32%) with splenomegaly, 26 (20%) with hepatomegaly and 96 (72%) were managed with Sodium stibogluconate (SSG) monotherapy. Thirty-four cases (26%) received Full haemogram (FHG) test and none had more than one Liver Function Tests (LFTs) in a span of 6 months. Presenting with headache (OR: 4.21, 95% CI: 1.10-16.09) and hepatomegaly (OR: 4.2, 95% CI: 1.30-14.11) were associated with VL death. No VL case management training had been conducted nor VL treatment guidelines distributed among health care workers (HCWs) in the last 1 year. CONCLUSIONS:VL cases were confirmed. Inadequate case monitoring and management was evident. VL case management sensitization training was conducted. The County health department should put in place one health VL surveillance and facilitate periodic case management trainings.
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Project description:Dogs are the main reservoir of zoonotic visceral leishmaniasis. Vaccination is a promising approach to help control leishmaniasis and to interrupt transmission of the Leishmania parasite. The promastigote surface antigen (PSA) is a highly immunogenic component of Leishmania excretory/secretory products. A vaccine based on three peptides derived from the carboxy-terminal part of Leishmania amazonensis PSA and conserved among Leishmania species, formulated with QA-21 as adjuvant, was tested on naive Beagle dogs in a preclinical trial. Four months after the full course of vaccination, dogs were experimentally infected with Leishmania infantum promastigotes. Immunization of dogs with peptide-based vaccine conferred immunity against experimental infection with L. infantum. Evidence for macrophage nitric oxide production and anti-leishmanial activity associated with IFN-γ production by lymphocytes was only found in the vaccinated group. An increase in specific IgG2 antibodies was also measured in vaccinated dogs from 2 months after immunization. Additionally, after challenge with L. infantum, the parasite burden was significantly lower in vaccinated dogs than in the control group. These data strongly suggest that this peptide-based vaccine candidate generated cross-protection against zoonotic leishmaniasis by inducing a Th1-type immune response associated with production of specific IgG2 antibodies. This preclinical trial including a peptide-based vaccine against leishmaniasis clearly demonstrates effective protection in a natural host. This approach deserves further investigation to enhance the immunogenicity of the peptides and to consider the possible engineering of a vaccine targeting several Leishmania species.
| S-EPMC6884440 | biostudies-literature
Project description:Visceral leishmaniasis (VL) is fatal if left untreated. Infected dogs are important reservoirs of the disease, and thus specific identification of infected animals is very important. Several diagnostic tests have been developed for canine VL (CVL); however, these tests show varied specificity and sensitivity. The present study describes the recombinant protein rLc36, expressed by Leishmania infantum, as potential antigen for more sensitive and specific diagnosis of CVL based on an immunoenzymatic assay. The concentration of 1.0 μg/mL of rLc36 enabled differentiation of positive and negative sera and showed a sensitivity of 85% and specificity of 71% (with 95% confidence), with an accuracy of 76%.
| S-EPMC5804312 | biostudies-literature
Project description:Although the strain causing cutaneous leishmaniasis (CL) in Sri Lanka was first identified in 2003, the strain causing visceral leishmaniasis (VL) has not yet been identified. We report the first isoenzyme typing of a strain causing VL in Sri Lanka at an early stage of emergence of VL in the country. The parasite was isolated from a 57-year-old civil soldier who had been in the jungle in the Vavuniya district in the Northern Province of Sri Lanka for a period of nearly 6 months immediately before the onset of symptoms. Multilocus enzyme electrophoresis (MLEE) revealed that the strain is Leishmania donovani zymodeme MON-37, the zymodeme which was previously identified from the CL patients in the country. The MLEE analysis was confirmed by sequencing the gene encoding the 6-phosphogluconate dehydrogenase isoenzyme. This is an instance of the same Leishmania zymodeme associated with both dermotropism and viscerotropism in the same geographic region. Further investigations into the genetic structure and identification of virulence factors in the parasite and immune factors in the host are required to understand the factors responsible for different tropism shown by the same zymodeme MON-37 L. donovani from Sri Lanka.
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Project description:Immunotherapy of canine visceral leishmaniasis (CVL) may provide an alternative to both marginally effective chemotherapy and undesired euthanasia of infected dogs and could have a great impact not only on animal welfare, but also on control of human disease. Therefore, we examined the potential immunotherapeutic efficacy of the subunit vaccine Leish-111f+MPL-SE, which has undergone rigorous preclinical testing and been demonstrated safe in human clinical trials. Two separate trials were performed in Salvador, Brazil, to evaluate the vaccine for therapeutic efficacy against CVL caused by natural infection: an Open Trial and a Blinded Trial. In the Open Trial 59 dogs with clinically active CVL were sequentially allocated to four groups: group 1 received Leish-111f+MPL-SE; group 2 was treated with Glucantime; group 3 received a combination of the vaccine and Glucantime; and group 4 was given no treatment. At the 6-month assessment, the 13 non-treated dogs had either died or showed no clinical improvement. In contrast, most dogs in groups 1-3 showed initial improvement (100%, 80%, and 92%, respectively). Upon evaluation for a mean of 36 months after therapy, the following cure rates were observed: 75% for group 1 dogs (exact 95% confidence interval [CI] 43-95%), 64% for group 2 dogs (exact 95% CI 31-89%), and 50% for group 3 dogs (exact 95% CI 19-81%). Therapeutic efficacy of the Leish-111f+MPL-SE vaccine was reconfirmed in a subsequent Blinded Trial. The vaccine was effective for mild cases of CVL and was compromised in dogs with severe disease. Although further studies are required to understand mechanisms of action, the Leish-111f+MPL-SE vaccine is a promising tool to control VL in both dogs and humans.
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Project description:This article reviews essential topics of canine visceral leishmaniasis (CVL) due to Leishmania infantum infection. It focuses on the current serological and molecular diagnostic methods used in epidemiological research and veterinary clinics to diagnose CVL and includes new point-of-care (POC) tests under development. The efficacy of different treatment regimens on the clinical improvement and infectiousness of dogs is also addressed. In the last section, the review provides a critical appraisal of the effectiveness of different control measures that have been implemented to curb disease transmission.
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