Leishmania (Mundinia) orientalis n. sp. (Trypanosomatidae), a parasite from Thailand responsible for localised cutaneous leishmaniasis.

BACKGROUND: Leishmaniasis is an emerging disease in Thailand with an unknown incidence or prevalence. Although the number of properly characterized and clinically confirmed cases is about 20, it is suspected that this low number masks a potentially high prevalence, with clinical disease typically manifesting itself against an immunocompromised background, but with a substantial number of subclinical or cured cases of infection. To date leishmaniasis in Thailand has been mainly ascribed to two taxa within the recently erected subgenus Mundinia Shaw, Camargo & Teixeira, 2016, Leishmania (Mundinia) martiniquensis Desbois, Pratlong & Dedet, 2014 and a species that has not been formally described prior to this study. RESULTS: A case of simple cutaneous leishmaniasis was diagnosed in a patient from Nan Province, Thailand. Molecular analysis of parasites derived from a biopsy sample revealed this to be a new species of Leishmania Ross, 1908, which has been named as Leishmania (Mundinia) orientalis Bates & Jariyapan n. sp. A formal description is provided, and this new taxon supercedes some isolates from the invalid taxon "Leishmania siamensis". A summary of all known cases of leishmaniasis with a corrected species identification is provided. CONCLUSIONS: Three species of parasites are now known to cause leishmaniasis is Thailand, L. martiniquensis and L. orientalis n. sp. in the subgenus Mundinia, which contains the type-species Leishmania enriettii Muniz & Medina, 1948, and a single case of Leishmania infantum Nicolle, 1908. This study now enables epidemiological and other investigations into the biology of these unusual parasites to be conducted. It is recommended that the use of the taxonomically invalid name "L. siamensis" should be discontinued.

Cytomorphologic comparison between rehydrated air-dried and conventional wet-fixed pap smears.

OBJECTIVE: To compare the cytomorphologic quality of the cervical (Pap) smears between two fixation techniques, rehydration of air-dried smears (AD) versus wet fixation (WF). MATERIAL AND METHOD: Paired-cervical smears (AD and WF) from 172 women who underwent cervical cytology screening at Chiang Mai University Hospital between August 2004 and September 2004 were prospectively evaluated for the cytologic parameters and the staining qualities. RESULTS: The mean age of the 172 women was 41.7 years +/-2 SD 18.1), 27 women (15.7%) were postmenopausal. Absence ofred blood cells in the smear background was significantly more frequent in AD smears than in WF specimens (p = 0.0006). Air-drying artifact was more frequent in AD smears compared to those of WF (p = 0.036) but was of only mild degree in all cases. There was no significant difference between AD and WF smears in the cytoplasmic quality including distinctness of cell border (p = 0.30) and satisfactory staining (p = 0.054). For the nuclear morphology, there was no significant difference between both fixation techniques in the distinctness of nuclear border (p = 0.26) and chromatin crispness (p = 0.23) of the endocervical nuclei. In squamous nuclei, AD smears had higher frequency of indistinct nuclear border and hazy chromatin compared to WF smears (p = 0.003 each). However, these were observed in only mild degree and did not affect the cytologic interpretation. CONCLUSION: The quality of AD smears was slightly inferior to WF smears but was still satisfactory for cervical cytology. AD technique may be acceptable as an alternative to wet fixation in cytologic cervical cancer screening.