Clinical Presentation of American Tegumentary Leishmaniasis in a Leishmania (Viannia) braziliensis Endemic Hotspot: A 35-Year History.

American tegumentary leishmaniasis (ATL) is a neglected tropical disease affecting the skin and mucosa. American tegumentary leishmaniasis due to Leishmania (Viannia) braziliensis is endemic in Argentina, where the Department of Oran is a hyperendemic focus. All cases of ATL with laboratory confirmation evaluated at a referral center in Oran city between 1985 and 2019 were analyzed retrospectively. Information from cases included clinical form, lesion size and number, time of evolution, and anatomical location; sex, age, and geographic origin were also studied. The temporal distribution of cases was analyzed. A total of 3,573 cases were included in the analysis. The ratio of males to females was 3:1 and the median age was 33 years old. Eighty-seven percent of cases were from Oran city and its surroundings, highlighting the hyperendemic nature of the area. Regarding clinical forms, 92.5% of cases were cutaneous and 7.5% were mucosal, with a median evolution time until clinical evaluation of 30 days and 7 months, respectively. Single cutaneous lesions were more frequent, localized mainly on the exposed areas in the upper and lower limbs. Secondary events were observed and described in 140 (4%) cases, with a median interval of 3.8 years for the appearance of recurrent mucosal disease in previously cutaneous forms. This is the largest case series of ATL due to L. (V.) braziliensis. The most classic presentation is of adult males with single cutaneous ulcers in exposed body areas, with < 10% of cases with mucosal complications. This comprehensive clinical characterization serves as a basis for future studies of the care and control of this neglected tropical disease.

Parasitological and molecular search for Leishmania natural infection in phlebotomine sand flies in peri-urban and rural sites of an Argentinean area endemic for tegumentary leishmaniasis.

Leishmaniases are neglected tropical diseases caused by Leishmania spp. parasites transmitted by the bite of phlebotomine sand flies. In Argentina, the most endemic area of American tegumentary leishmaniasis (ATL) has been Orán department, Province of Salta, where Leishmania (Viannia) braziliensis prevails and Nyssomyia neivai is considered as its vector, although there is no accurate and sufficient information in this regard. The aim of this work was to search for natural infection by Leishmania spp. in sand flies from peri-urban and rural sites with ATL background in Orán department. For this, sand flies were caught at five sites; female sand flies captured with Shannon trap were dissected to microscopically examine their gut contents, while females captured with CDC traps were molecularly analyzed by duplex PCR with two primer pairs to simultaneously amplify kinetoplast DNA (kDNA) and mammalian actin. A total of 1921 females were captured, with Ny. neivai being the most abundant species (89%), followed by Migonemyia migonei (6%) and cortelezzii complex (3%). No natural infection was found in any of them neither by dissection nor by PCR, although the detection limit of kDNA PCR was up to 25 promastigotes. The absence of infected females in peri-urban sites suggest that the transmission did not take place in those environments during the study period. Future searches for natural infection should focus on rural settings to deepen knowledge and elucidate the role of the circulating sand fly species as all have been linked to ATL transmission at other sites.

Sand fly typing: a simple and morphologically-supported method based on polymorphism of 18S rRNA gene in a Leishmaniasis endemic area of Argentina.

Leishmaniases are vector-borne diseases that in the Americas are distributed from southern United States to northern Argentina. The vectors for this disease are small dipterans known as sand flies that are usually identified morphologically by observing structures with taxonomic value; but it is time-consuming, laborious, and requires entomological expertise. Then, this work was aimed at identifying sand flies with molecular techniques, using the morphological identification as a reference technique, in an endemic area of American Tegumentary Leishmaniasis (ATL) located in northern Argentina. For this, sand flies were caught at two patches of vegetation adjacent to rural areas in Orán department, Salta Province. Females were dissected with sterile needles; the head and last abdominal segments were analyzed for morphological identification. The remaining thorax and abdominal segments were used to extract DNA, which was amplified by PCR of the small subunit (SSU), 18S rRNA gene. PCR products were digested with CviQI and DdeI enzymes to identify sand fly species by Restriction Fragment Length Polymorphism (RFLP) analysis. Thus, the restriction pattern of each caught species was defined according to morphological identification. A total of 1501 females, belonging to four sand fly species, were captured. Nyssomyia neivai (1347/1501) was the most abundant species, followed by Migonemyia migonei (90/1501). From the total, 801 females were morphologically and molecularly identified, while 700 females were characterized only molecularly. For those females analyzed by both methods, there was total coincidence in the achieved result. Besides, the 5% (38/801) of females that could not be determined morphologically due to inadequate mounting were molecularly identified. All the females characterized just by PCR-RFLP, were successfully identified. Our results indicate that the explored method is capable of identifying the sand fly species that circulate in an ATL endemic area. Since this method is based on the analysis of markedly different patterns, the identification process might be more easily reproduced, as the bias introduced by the technician's lack of experience is removed.