Empleo del hamster dorado como animal centinela en las localidades donde es endemica la uta (leishmaniasis tegumentaria. / Use of the golden hamster as sentinel animal in areas where uta (cutaneous leishmaniasis) is endemic

Durante 2 anos consecutivos se ha empleado el hamster dorado como animal centinela en una localidad donde es endemica la leishmaniasis tegumentaria conocida con el nombre de uta.Se obtuvo resultados positivos en 21 (44,7%) de los 47 hamsters en los que se investigo la posible infeccion leishmaniasica; esta vario en forma marcada en relacion con las estaciones del ano, siendo mayor en verano y otono. El parasito fue puesto de manifiesto por medio de frotis coloreados y/o cultivos de las lesiones de la piel; en algunos hamsters tambien se le cultivo areas de la piel con aspecto normal. La presencia del parasito fue demostrada predominantemente en las orejas, em segundo lugar en las patas, y tan solo en 2 ocasiones en la nariz; fue frecuente su presencia simultanea en 2 sitios distintos.En las orejas se observo 2 tipos diferentes de lesiones, tan solo uno de los cuales parece ser de etiologia leishmaniasica. Se considera en las localidades donde es endemica la uta y, a la especie de Leishmania encontrada como el posible agente etiologico de esta enfermedad

Lutzomyia peruensis Shannon, 1929, posible vector natural de la uta (leishmaniasis tegumentaria). / Lutzomyia peruensis Shannon, 1929, possible natural vector of uta (cutaneous leishmaniasis)

Se informa haber aislado 2 cepas de una especie dermatotropica de Leishmania, a atraves de hamsters que fueron inoculados con triturados de Lutzomyia peruensis capturados em localidades donde la uta es endemica.Un total de 97 especimenes de Lu. peruensis, divididos en 7 lotes, fueron triturados y luego inoculados en sendos hamsters, 2 de los cuales fueron infectados. El desarrollo de la infeccion en ambos hamsters fue semejante al que se obtiene en este roedor quando se le inocula con cultivos del agente etiologico de la uta.Por los habitos antropofilicos de Lu. peruensis,la correlacion en la distribucion altitudinal de este insecto y el de la uta, asi como por las caracteristicas de la infeccion experimental de las cepas aisladas en el hamster dorado, se supone que: a) la especie de Leishmania aislada sea el agente etiologico de la uta; y b) Lu. peruensis sea el transmisor natural de esta enfermedad

Leishmania braziliensis in the Panamanian two-toed sloth, Choloepus hoffmanni.

A total of 498 two-toed sloths, Choloepus hoffmanni, collected in central Panama was examined for Leishmania braziliensis over a 10-year period. Isolations of the parasite from 96 (19.3%) of the animals were confirmed by culture and inoculation of golden hamsters. Improved culture techniques developed toward the end of the study assisted in determining a greater prevalence of the disease. Infectins were completely cryptic in all animals, and the parasite was isolated from skin, blood, liver, spleen, bone marrow and lung tissues. Sloths maintained under seminatural conditions remained infected up to 23 months, the longest period of survival. This edentate, considered the principal reservoir host of L. braziliensis in Panama, showed infection rates from 0-59.4% in various communities, which appeared to correlate with the parasite prevalence in the indigenous human populations.

Panamanian forest mammals as carriers of Salmonella.

Enteric bacteria pathogenic to man were sought in a total of 974 forest mammals collected from a variety of sites in rural and jungle areas of Panamá. The highest incidence of infection among the mammals was observed during the Panamanian dry season, which normally extends from January through April. A minimum of 10 Salmonella serotypes including, three of the Arizona group and Ewardsiella tarda, was isolated. Opossums of the genera Philander, 11 of 54 (20.1%), and Didelphis, 12 of 102 (11.8%) demonstrated high infection rates. One sloth of the genus Choloepus and specimens of two genera of rodents also were infected to varying degrees: 1(11.1%) of 9 Choloepus, 8 (1.1%) of 704 Proechimys and 1 (16.7%) of 6 Diplomys.

Epidemiological patterns of cutaneous leishmaniasis in Panama. I. Epidemics among small groups of settlers.

Epidemic of cutaneous leishmanniasis among a small group of people established in a Panamanian forested area was studied. The first settlers arrived in June 1971, and by June 1973 there were 37 persons, 33 of whom had no previous history of the disease. Epidemiological surveys were made in June 1973 and March 1974. The disease developed in 14 (42.4%) of the 33 susceptible persons by June 1973, with an exposure time ranging from one to 14 months. The last case occurred in April 1973, and no new cases were observed during the ensuing 11 months. Two (15.4%) of 13 dogs examined were found with cutaneous leishmaniasis, but none of 41 feral mammals studied, mainly terrestrial rodents, was infected. Four leishmanial strains characterized, three from patients and one from a dog, were identified as Leishmania braziliensis. Phlebotomine sandfly population composition was studied and the probable vectors involved in the transmission to man were determined.

Epidemiological patterns of cutaneous leishmaniasis in Panama. II. Incidental occurrence of cases in non-endemic settlements.

Epidemiological studies on cutaneous leishmaniasis were carried out in a settlement in the Bayano region, Republic of Panama, during 1971-72. This settlement was established about 12 years earlier for the purpose of cattle raising by small groups of settlers. The primary forest was cut and cleared and the area planted with grass. The presence of active cases of cutaneous leishmaniasis among humans and animals, both domestic and ferals, was investigated. In addition, phlebotomine sandflies were collected to determine their species composition. In 1971, nine of the 161 persons interviewed had active lesions; all but one of the patients were males and of these seven were adults. Five (9%) of 55 dogs and one (3%) of 33 feral mammals examined also were found infected. Strains of the parasite infecting both humans and animals were characterized as Leishmania braziliensis. About 60% of the sandflies collected belong to four man-biting species previously incriminated as vectors of human cutaneous leishmaniasis in Panama. The extensive pasture, together with periodic applications of insecticides in the houses by the antimalarial agency in this country, provided an effective barrier against transmission within the settlement itself. However, both humans and dogs acquired the disease during excursions into the surrounding forest. No new cases were found in 1972.

Epidemiological patterns of cutaneous leishmaniasis in Panama. III. Endemic persistence of the disease.

Endemic persistence of cutaneous leishmaniasis is described in El Aguacate, a community established in the forest of central Panama about 75 years ago. Physiographic pecularities partially isolate El Aguacate from other villages in the region. Some of the original forest environment has been preserved and man-biting species of phlebotomine sandflies were abundant as was the two-toed sloth, Choloepus hoffmanni, the principal reservoir host of Leishmania braziliensis in Panama. The inhabitants, as well as their dogs, were examined for natural leishmaniasis in 1969 and 1973. Mammals and phlebotomine sandflies were collected from 1968 to 1973 in a search for reservoir hosts and potential vectors of the disease. Similar studies were undertaken in two nearby villages during 1968 and 1969. L. braziliensis has persisted for many years in El Aguacate, and infection is acquired during childhood. Dogs also were found naturally infected, and the two-toed sloth showed yearly infection rates up to 47.8%. Parasites were demonstrated from a night monkey, Aotus trivirgatus.

Natural cutaneous leishmaniasis among dogs in Panama.

A search for cutaneous leishmaniasis among dogs was conducted in several forest settlements of central Panama from 1968 to 1973. A total of 11 (3.3%) of 333 animals examined was found infected and, in 9 of these, parasites were isolated in culture and characterized as Leishmania braziliensis. Infected dogs occurred in three settlements, one of which was free of human leishmaniasis. In the latter case, infections were acquired in the nearby forest during hunting excursions. Ulcerated skin lesions primarily on the lower aspect of ears, or depigmentation and inflammation of the nostrils were manifested, with persistence as long as 45 months. The parasites did not disseminate from the lesion to viscera or other areas of the skin. The dog may serve as an incidental reservoir host of human leishmaniasis and/or a liaison of the infection between the jungle and forest settlements in the Republic of Panama.