Short report epidemiologic studies on cutaneous leishmaniasis in eastern Panama.

Abstract

Abstract. The Panamanian Ministry of Health, through the Interamerican Development Bank, contracted the Gorgas Memorial Laboratory to conduct epidemiologic studies on leishmaniasis and malaria in eastern Panama from July 1984 through June 1985. Preliminary results of the biomedical and entomologic teams investigating the epidemiology of cutaneous leishmaniasis in the eastern part of the country are presented in this short report. The principal findings of the study revealed 1) a large disparity in the incidence and prevalence of the disease among the five communities investigated; 2) the appearance of self-cures without the benefit of effective treatment; 3) a relatively high percentage of subclinical cases; and 4) determination of the sandfly vector species for each community. Also reported here is a case of a double infection with two distinct species of Leishmania, L. mexicana and L. amazonensis, in a single individual.The present study investigated epidemiologic parameters of cutaneous leishmaniasis among five communities in eastern Panama in which week-long surveys were conducted. This study was reviewed and approved by the Panamanian Ministry of Health. Four of these study sites (San Miguel, Torti, Santa Fe, and Meteti) are adjacent to the Interamerican Highway (Figure 1). The fifth community (Boca de Sabalo) is located in the extreme southeastern part of the country, and was accessed by boat via an extensive river system (Figure 1). Although the primitive working conditions in the communities precluded isolation and characterization of the parasite, it was assumed that all of the cases of leishmaniasis encountered were due to Leishmania panamensis since it has been the predominant species identified from human cases in Panama. However, several months after the termination of the project, one of the investigators (JLP) developed a lesion from which a biopsy specimen was obtained and found to be caused by L. amazonensis. 1 The locality in which the infection occurred could not be determined since this investigator traveled extensively throughout Panama during the study period.In 1977, several U.S. soldiers conducting jungle exercises near the Caribbean entrance to the Panama Canal developed leishmaniasis identified by personnel at Gorgas Memorial Laboratory (GML) as caused by L. amazonensis.1,2 In October 1986, the first indigenous case of infection with L. mexicana in Panama was isolated from one of two lesions from a young mestizo individual involved in hunting and agriculture in the northern and eastern part of the country. 1 Eight subsequent clones of parasites from each lesion revealed a double infection with L. mexicana and L. amazonensis. A new species, L. colombiensis, was isolated from four sand flies and a sloth in Panama, and from two humans and a sand fly in Colombia. 3 With regard to the remaining two species indigenous to Panama, L. hertigi appears to be host-specific for the porcupine Coendou rothschildi, and L. aristidesi is known only from a single focus in a coastal forest in eastern Panam...

Molecular Epidemiology of American Tegumentary Leishmaniasis in Panama

“…9 Although human samples from all the endemic regions of the country were analyzed, there is an underrepresentation in our sample of some endemic areas, particularly from remote zones located near neighboring countries where other Leishmania species have been reported. Therefore, based on previous reports, [9][10][11][12] we cannot exclude the current presence in the country of other human Leishmania species. In this regard, studies in particular endemic areas such as the Darien province near the Colombian border are necessary to confirm the taxonomy of Leishmania parasites that infect humans in these communities.…”

“…Lutzomyia species implicated in the transmission of L. mexicana and L. amazonensis were not identified in this study, although sporadic human cases caused by these species have been reported in the country. [9][10][11][12] The natural vector of AVL, Lu. longipalpis , was not captured.…”

“…As an immunologic indicator of exposure to Leishmania parasites, the intradermal reaction of Montenegro (IDRM) was performed as described elsewhere, 9 using a mix of promastigotes of three autochthonous L. ( V. ) panamensis strains isolated from different endemic regions in the country maintained at Gorgas Institute in Panama. Comparison between diagnostic techniques was performed estimating the overall percent agreement and κ index.…”

“…[9][10][11][12] L. colombiensis was isolated from four sand flies and a sloth in Panama. 13 Two other Leishmania species have been reported in Panama but never isolated from humans.…”

“…7,8,19 Coincidentally, these species are the most abundant in the country. 3,9 American visceral leishmaniasis (AVL) has never been reported in Panama; however, Lutzomyia longipalpis , the natural vector of this severe clinical form, has been found. 20 In Panama, leishmaniasis is a communicable disease.…”