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

In 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 (1994-2004) 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.

Comparison of small mammal prevalence of Leishmania (Leishmania) mexicana in five foci of cutaneous leishmaniasis in the State of Campeche, Mexico / Comparación de las prevalencias de Leishmania (Leishmania) mexicana en mamíferos pequeños en cinco focos de leishmaniosis cutánea en el estado de Campeche, México

In 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 (1994-2004) 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.

En la Península de Yucatán, México, la Leishmaniosis Cutánea es causada por Leishmania (L.) mexicana en 95% de los casos humanos, con una incidencia de 5.08% por cada 100,000 habitantes. El ciclo de transmisión se limita a la estación de invierno (noviembre- marzo). Un estudio de mamíferos silvestres incrimina a Ototylomys phyllotis y Peromyscus yucatanicus como reservorios primarios de L. (L.) mexicana en el foco de infección de La Libertad, Campeche. En el presente estudio, se documenta la prevalencia de infección/enfermedad causada por L. (L.) mexicana en pequeños mamíferos, durante cinco estaciones de transmisión (1994-2004) en cinco focos de CL del estado de Campeche. Los focos separados por solamente 100 km. de distancia, aún cuando tienen abundancias relativas de pequeños roedores similares, fueron significativamente diferentes en relación a la prevalencia de síntomas así como de infección. Las tasas de transmisión y las especies de reservorios parecen estar cambiando tanto en el tiempo como en el espacio, lo cual impide el establecimiento de adecuadas medidas de control de la enfermedad aún en un área endémica tan pequeña como lo es el sur de la Península de Yucatán.

Clinical picture of cutaneous leishmaniases due to Leishmania (Leishmania) mexicana in the Yucatan peninsula, Mexico.

Localized cutaneous leishmaniasis (LCL), known as "chiclero's ulcer" in southeast Mexico, was described by Seidelin in 1912. Since then, the sylvatic region of the Yucatan peninsula has been identified as an endemic focus of LCL. The purpose of the present work was to describe the clinical picture of LCL caused by Leishmania (Leishmania) mexicana in the Yucatan peninsula. A total of 136 cases of LCL, based on isolation and characterization of L. (L.) mexicana by isoenzymes and/or monoclonal antibodies, were selected. Some variability of clinical features regarding number, type, size, form, location and time of evolution of the lesions was observed. The most frequently observed presentation was a single, ulcerated, rounded small lesion, located on the ear, with an evolution time of less than three months, with neither cutaneous metastases nor lymphatic nor mucosal involvement. This picture corresponds to previous studies carried out in the same endemic area where an organism of the L. mexicana complex has been incriminated as a major aetiological agent of classical "chiclero's ulcer", confirming that in the Yucatan peninsula LCL due to L. (L.) mexicana when located on the pinna of the ear is a remarkable characteristic.

Retention of Leishmania (Leishmania) mexicana in naturally infected rodents from the State of Campeche, Mexico.

In the State of Campeche, Mexico, zoonotic cutaneous leishmaniasis is mainly due to Leishmania (L.) mexicana. The parasite population is maintained in a mammalian species, a reservoir in which the ideal course of infection should be long and relatively nonpathogenic. The objective of the present study was to document the retention of L. (L.) mexicana in 29 naturally infected rodents. These cricetids lived in captivity for up to two years and were tested monthly for the presence of the parasite, by cultures of needle aspirates from the base of the tail. Peromyscus yucatanicus and Ototylomys phyllotis were incriminated as the primary reservoir hosts. The finding that the multiplication of parasites in P. yucatanicus might be triggered by temperature, suggests that this animal would be a good choice for further research on L. (L.) mexicana.

Use of monoclonal antibodies for the identification of Leishmania spp. isolated from humans and wild rodents in the State of Campeche, Mexico.

The genus Leishmania includes 30 described species which infect a wide variety of mammalian hosts. The precise identification of leishmanial parasites at the species level is very important in order to determine whether an organism, causing the disease in a given area, is of the same biotype as that found in suspected mammalian reservoirs. The objectives of the present study were (1) to identify leishmanial parasites isolated from humans and wild rodents from the State of Campeche, an endemic focus of localized cutaneous leishmaniasis (LCL) in southern Mexico, using an indirect immunofluorescent assay (IFA) with monoclonal antibodies (Mabs); and (2) to determine if the parasites of the two types of hosts were of the same biotype. All the wild rodents (six Ototylomys phyllotis, eight Oryzomys melanotis, five Peromyscus yucatanicus and two Sigmodon hispidus) and 96% (24/25) of the human isolates were identified as Leishmania (L.) mexicana confirming that this specific LCL focus is a wild zoonosis. The presence of one human isolate of L. (Viannia) braziliensis in the State of Campeche, confirmed the importance of an accurate taxonomic identification at species level.

Response of cutaneous leishmaniasis (chiclero's ulcer) to treatment with meglumine antimoniate in Southeast Mexico.

Cutaneous leishmaniasis, known as chiclero's ulcer in southeastern Mexico, is characterized by a predominantly single, painless, ulcerated lesion, without lymphangitis or adenopathy. When located on the ear, it tends to become chronic, causing destruction of the pinna and disfigurement. It is caused predominantly by Leishmania (L.) mexicana. Although pentavalent antimonials (Sb5+) are the mainstay of leishmanial therapy and have been used for more than 50 years, dosage regimens have been repeatedly modified and the best one has not been fully identified. The main purpose of the present study was to investigate the response of chiclero's ulcer to treatment with meglumine antimoniate. One hundred five patients were treated with meglumine antimoniate at a daily dose of 1 ampule per day (425 mg of Sb5+) until healing. The lesions healed after a mean of 25 days (range = 5-60 days).

Isoenzyme characterization of Leishmania isolated from human cases with localized cutaneous leishmaniasis from the State of Campeche, Yucatan Peninsula, Mexico.

Seventy-five isolates from the State of Campeche, Mexico, an area endemic for localized cutaneous leishmaniasis (LCL), were characterized by isoenzyme markers (glucose phosphate isomerase, mannose phospate isomerase, nucleoside hydrolase, phosphoglucomutase, 6-phosphogluconate dehydrogenase, and glucose-6-phosphate dehydrogenase). Seventy (93.3%) were identified as Leishmania (Leishmania) mexicana and 5 (6.7%) as L. (Viannia) braziliensis. This is the first report of authochthonus human LCL caused by L. (V.) braziliensis in the State of Campeche, Yucatan Peninsula, Mexico.

Isolation of Leishmania (L.) mexicana from wild rodents and their possible role in the transmission of localized cutaneous leishmaniasis in the state of Campeche, Mexico.

Leishmania parasites were isolated from four of seven small rodent species captured in the State of Campeche, Mexico. Signs and/or symptoms of leishmanial infection were restricted to the tail of the mice. Peromyscus yucatanicus endemic to the peninsula of Yucatan and Oryzomys melanotis were added to the list of carriers of Leishmania. Leishmania (L.) mexicana, characterized by an indirect immunofluorescence antibody method using monoclonal antibodies, was identified in one Sigmodon hispidus and one Or. melanotis. The possible role of the different species as primary reservoirs of Leishmania in the peninsula of Yucatan is discussed.

[Leishmaniasis: a preliminary epidemiological study in a locality of the endemic area in the state of the Tabasco]. / Leishmaniasis: estudio epidemiológico preliminar en una localidad de la zona endémica del estado de Tabasco.

The state of Tabasco is localized in the endemic area of cutaneous leishmaniasis where both diffuse cutaneous leishmaniasis and mucocutaneous leishmaniasis have recently been reported. The objective of the present study was to obtain reliable information of the situation of this disease--which has a great relevance as a worldwide public health problem--through determination of the allergic index in a randomized sample from Ranchería Miguel Hidalgo, Comalcalco Municipality, Tabasco, Mexico. We found an allergic index of 56 per cent. Farmers and housewives had the highest positive responses to the Montenegro skin test. We found no statistical differences between males and females. Moreover, 3 patients with active lesions and people with scars suggestive of prior leishmaniasis were detected during the study. This village should be considered a high endemic focus.

Localized cutaneous leishmaniasis (chiclero's ulcer) in Mexico: sensitivity and specificity of ELISA for IgG antibodies to Leishmania mexicana mexicana.

Sera from 223 human beings were assayed by enzyme-linked immunosorbent assay for immunoglobulin G antibodies to Leishmania mexicana mexicana promastigotes. 76% of 74 sera from patients with chiclero's ulcer gave positive reactions at a titre of 1:40; the positivity rate was lower in patients with long-standing infections. False positive reactions were obtained with only 7% of 56 sera from healthy individuals with positive Montenegro tests and with 6 of 7 sera from patients with Chagas disease. It is concluded that this method would be a useful contributory diagnostic method in cases of suspected chiclero's ulcer.

Incidence of localized cutaneous leishmaniasis (chiclero's ulcer) in Mexico.

Cutaneous leishmaniasis in Mexico was first described in 1912. Since then, its existence has been repeatedly confirmed in the forest regions of the peninsula of Yucatan. In order to obtain reliable knowledge about the magnitude of this problem, we questioned and skin-tested a sample of 449 persons randomly selected from men aged 15-45 years. We found a positivity rate of 24 to 90% (mean 43%) in the seven rural health posts studied. Furthermore, 72 patients were examined between January and December 1987 by parasitological investigation (smear, isolation, culture and/or biopsy) and the Montenegro skin test; 56 had acquired the disease in 1987. Based on these data, we found an annual incidence rate of 508 per 100,000 inhabitants. Further long-term studies are indicated to determine the incidence and prevalence rates for this disease in other parts of the country.

Estudio preliminar de correlacion clinica, histopatologica e inmunologica de la leishmaniasis cutanea mexicana en el hombre. / Preliminary study of clinical, histopathological and immunological correlation of Mexican cutaneous leishmaniasis in the man

Se estudiaron un total de siete pacientes provenientes de area endemica y con cuadro clinico de leishmaniasis cutanea mexicana.Se les practicaron historia clinioepidemiologica, biopsia, evaluacion de perfil inmunologico (linfocitos T y B, determinacion de inmunoglobulinas y C3) y reaccion inmunitaria especifica (intradermorreaccion de Montenegro y ELISA). Clinicamente no se encontraron diferencias con lo informado en la literatura. El patron histopatologico es caracteristico y diferente a lo encontrado en otras leishmaniasis cutaneas. Inmunologicamente los hallazgos sobresalientes fueron hipergammaglobulinemia en 6/7 (85.71 por ciento) y ELISA positivo en 5/7 (71.42 por ciento). Se discuten las posibles correlaciones y se proponen criterios diagnosticos