Comparison of small mammal prevalence of Leishmania (Leishmania) mexicana in five foci of cutaneous leishmaniasis in the State of Campeche, Mexico

Abstract

sUMMaRyIn the Yucatan Peninsula of Mexico, 95% of the human cases of Cutaneous Leishmaniasis are caused by Leishmania (Leishmania) mexicana with an incidence rate of 5.08 per 100,000 inhabitants. Transmission is limited to the winter months (November to March). One study on wild rodents has incriminated Ototylomys phyllotis and Peromyscus yucatanicus as primary reservoirs of L. (L.) mexicana in the focus of La Libertad, Campeche. In the present study, the prevalence of both infection and disease caused by L. (L.) mexicana in small terrestrial mammals were documented during five transmission seasons (1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004) in five foci of Leishmaniasis in the state of Campeche. Foci separated by only 100 km, with similar relative abundances of small mammals, were found to differ significantly in their prevalence of both symptoms and infection. Transmission rates and reservoir species seemed to change in space as well as in time which limited the implementation of effective control measures of the disease even in a small endemic area such as the south of the Yucatan Peninsula.

Preliminary study towards a novel experimental model to study localized cutaneous leishmaniasis caused bY Leishmania (Leishmania) mexicana

“…Parasite demonstration: Based on previous studies in which local signs of infection by L. (L.) mexicana were always located at the base of the tail 10,11,35,36 , smears were made from samples collected at the edge of the lesion (avoiding ulcerated and/or heavily crusted parts) or from the inoculation site in absence of local signs. Moreover, smears were made from the liver and spleen samples.…”

“…As described previously a criterion to incriminate a primary reservoir of Leishmania stated that the infection in a reservoir species should be relatively nonpathogenic, that is, the infection should not lower the survival possibility of the animal since it has to live until the next transmission season, which is more than seven months in the Peninsula. In other words, the immune system of the reservoir must react to the presence of the parasite in such a manner that while preventing irrevocable damage, the parasite evades sterilizing immunity 36 .…”

“…Allen and Chapman, 1897; and Heteromys gaumeri J.A. Allen and Chapman, 1897 10,11,35,36 . The two latter species are endemic in the Yucatan Peninsula.…”

<i>Leishmania</i> in Marsupials—An Overview of Infection Records in the Americas and Australia

“…In Mexico, Van Wynsberghe et al [60] observed that in addition to high rates of infection (50% and 100% during 1997-1998 and 2001-2004, respectively), most animals were asymptomatic in certain areas of an important focus of cutaneous leishmaniasis in the state of Campeche (Table 4). …”

Eco-Epidemiological and Immunological Features of Localized Cutaneous Leishmaniasis in Southeastern Mexico: Thirty Years of Study

“…The first attempt to find leishmanial hosts close to the Yucatan Peninsula was carried out in Belize in the early 1960s [29][30][31]. However, the south of Belize has to be considered as a different endemic area of the disease since this area is not part of the Biotic Province of the Peninsula of Yucatán [32] [18,33,34]. Thus, many small terrestrial mammals of the Peninsula seemed to be able to harbour the parasite.…”