Abstract. Polymerase chain reaction was used to detect Leishmania siamensis DNA from clinical samples collected from six leishmaniasis patients during 2011-2012. The samples used in this study came from bone marrow, blood, buffy coat, saliva, urine, and tissue biopsy specimens. Saliva was a good source for L. siamensis DNA by polymerase chain reaction. L. siamensis DNA was also found in saliva of an asymptomatic case-patient. Levels of L. siamensis DNA in saliva decreased until being undetectable after treatment. These levels could be used as a marker to evaluate efficacy of the treatment. A larger study is needed to evaluate this method as a screening and survey tool to study the silent background of Leishmania infection among the at-risk population.Leishmaniasis is a neglected tropical diseases caused by an obligate intracellular protozoa belonging to the genus Leishmania. The disease is transmitted to vertebrate hosts by infected female sand flies taking a blood meal.1 Leishmaniasis presents in three clinical forms; visceral, cutaneous, and mucocutaneous.2 Clinical presentation of leishmaniasis depends on the species of Leishmania and the immunity of the host. Detection and species identification of the parasites is essential for prognostic and therapeutic reasons and surveys.
In a randomized open study, we compared the efficacy of a single dose of oral ivermectin (200 microg/kg) and oral albendazole (400 mg/day for 21 days) for the treatment of cutaneous gnathostomiasis. Thirty-one patients were randomly assigned to receive ivermectin (n = 17) or albendazole (n = 14). Thirteen of 17 patients who received ivermectin responded, 3 relapsed, and 1 was unresponsive (cure rate = 76%). Thirteen of 14 patients who received albendazole responded very well and did not relapse. Only one patient was unresponsive (cure rate = 92%; P > 0.05). No major side effects were observed in both groups. We concluded that a single dose of ivermectin (200 microg/kg) is less effective than albendazole (400 mg/day for 21 days) for treatment of cutaneous gnathostomiasis, but there was no statistically significant difference (P > 0.05).
Gnathostoma spinigerum infection is endemic in Thailand and many Asian countries. Current diagnosis is the skin test and enzyme-linked immunosorbent assay (ELISA) for IgG antibody against the G. spinigerum third-stage larvae (L3), but cross-reactivity is common. We evaluated the sensitivity and specificity of anti-G. spinigerum L3 IgG subclass antibodies for diagnosis of 43 patients with gnathostomiasis. The majority of patients with gnathostomiasis (91%) had eosinophilia. While the anti-G. spinigerum L3 IgG1 antibody provided the highest sensitivity (98%), the anti-G. spinigerum L3 IgG2 antibody had the highest specificity (88%). The ELISA that detected anti-G. spinigerum L3 IgG1 antibody could be a reliable laboratory screening test, while anti-G. spinigerum L3 IgG2 antibody could be used to confirm the diagnosis.
BackgroundLeishmaniasis caused by two new species of Leishmania; L. siamensis and L. martiniquensis have been recently described in Thailand. The disease has mainly been documented in AIDS patients from southern Thailand. In this study, polymerase chain reaction (PCR) was used to determine HIV-Leishmania co-infection in southern Thailand.MethodsOne ml of saliva and 3 ml of EDTA blood were collected from HIV-infected patients for PCR detection of Leishmania DNA, cloning and sequencing. The positive PCR samples were then cultured on Schneider’s insect medium.ResultsThree out of 316 saliva samples collected from HIV-infected patients were found to be positive for Leishmania DNA (0.95 %). Among the positive samples, one patient was observed with disseminated cutaneous lesions and also tested positive via saliva, whole blood and buffy coat in PCR. The second case presenting with nodular lesions also gave a positive saliva test via PCR two months prior to buffy coat. This diagnosis was confirmed by microscopic examination and a culture of biopsy samples from a nodule. The last case was an asymptomatic Leishmania infection which tested PCR positive only in saliva with a consecutive sample collection conducted for three months.ConclusionsThe prevalence of Leishmania infection in HIV infected patients within this study is 0.95 %. Leishmania DNA was detected in saliva by PCR prior to blood and buffy coat of two HIV infected patients. Early detection of Leishmania DNA in saliva would be beneficial for the follow up of asymptomatic Leishmania infected patients, the early treatment of leishmaniasis and for surveillance survey purpose. However, full evaluation of sensitivity and specificity of this technique with a large cohort of patients is required before deployment.
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.
Five hundred and fifty-nine female biting midges were collected, and seventeen species in six subgenera (Avaritia, Haemophoructus, Hoffmania, Meijerehelea, Remmia, and Trithecoides) and two groups (Clavipalpis and Shortti) were identified. The dominant Culicoides species was C. peregrinus (30.94%), followed by C. subgenus Trithecoides. From blood meal analysis of engorged biting midges, they were found to feed on cows, dogs, pigs, and avians. The majority of blood preferences of biting midges (68%; 49/72) displayed a mixed pattern of host blood DNA (cow and avian). The overall non-engorged biting midge field infectivity rate was 1.44 % (7/487). We detected Leucocytozoon sp. in three Culicoides specimens, one from each species: C. fulvus, C. oxystoma, and C. subgenus Trithecoides. Crithidia sp. was found in two C. peregrinus specimens, and Trypanosoma sp. and P. juxtanucleare were separately found in two C. guttifer. More consideration should be paid to the capacity of biting midges to transmit pathogens such as avian haemosporidian and trypanosomatid parasites. To demonstrate that these biting midges are natural vectors of trypanosomatid parasites, additional research must be conducted with a greater number of biting midges in other endemic regions.
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