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Biomedical subjects

J J Shaw

Publications and source records attributed to J J Shaw.

At least 91 records · Page 5Linked to original sources

Epidemiology and ecology of leishmaniasis in Latin-America.

Of the diseases caused by protozoal parasites, leishmaniasis is probably second in importance only to malaria. Chemotherapeutic drugs are toxic, expensive and not 100% effective. This, and the absence of any non-living vaccine against the disease, means that control depends on eliminating either reservoirs or insect vectors, or both. Recently, a greatly increased knowledge of the Leishmania species involved, and of their natural hosts, has helped to define the nature and extent of the problem.

Animals↗

Some methods for membrane feeding of laboratory reared, neotropical sandflies (Diptera: Psychodidae).

A brief introduction to the history and applications of membrane feeding is given, together with its use to feed and infect sandflies with Leishmania. The present paper describes methods for feeding Lutzomyia longipalpis and Lu. flaviscutellata through membranes. Of the membranes tested, chick skins and bat wings gave the best results. Membranes stored at -20 degrees C for over a year were found to be less effective than fresh ones. Blood meals were maintained at temperatures between 24 degrees C and 37 degrees C and it is concluded that although temperatures as high as 37 degrees C are unnecessary for successful membrane feeding of sandflies, fewer flies feed in most instances at temperatures below 27 degrees C. The influence on feeding of individual skins, different lots of blood and the addition of leishmanial cultures to offered blood are discussed.

Animal Nutritional Physiological Phenomena↗

Leishmaniasis in Brazil: XII. Observations on cross-immunity in monkeys and man infected with Leishmania mexicana mexicana, L. m. amazonensis, L. braziliensis braziliensis, L. b. guyanensis and L. b. panamensis.

Cross-immunity trials in monkeys (Cebus apella apella) and observations on experimental and natural infections in man confirm the separate identity of L. mexicana mexicana, L. m. amazonensis, L. b. braziliensis, L. b. guyanensis and L. b. panamensis. Neither L. m. mexicana nor L. m. amazonensis infections gave protection against subsequent challenge with parasites of the L. braziliensis complex; but recovery from infection with subspecies of L. braziliensis in most cases gave firm resistance to infection with the mexicana parasites. The failure of certain New World leishmanias to immunize against each other has an important bearing on taxonomy, future attempts to prepare vaccines against Leishmania, epidemiology and diagnosis.

Animals↗

Pneumocystis and Histoplasma infections in wild animals from the Amazon region of Brazil.

Routine examination of tissues from wild forest rodents from Amapá, north Brazil, revealed Pneumocystis carinii in lung smears from a newly captured Oryzomys capito (Cricetidae). Acute, fatal infections with this parasite are also recorded in a number of captive "coatimundis", Nasua narica (Carnivora: Procyonidae) and a sloth, Bradypus tridactylus (Edentata). Pneumocystis was also encountered in lung smears from a newly captured and apparently healthy sloth, Choloepus didactylus. The presence of infection in newly captured animals leads us to believe that the fatal, fulminating pneumocystosis seen in the captive Nasua and Bradypus was due to exacerbation of pre-existant infections acquired in their natural forest environment. Pneumocystis carinii is a well known cause of fatal, interstitial plasma-cell pneumonia in human infants and sometimes the weakened adult: the keeping of exotic pets such as the coatimundi is, therefore, not without some hazard in this respect. Histoplasma, another well known pathogen for man, was isolated from 4 rodents, Proechimys guyanensis (Echimyidae), all from virgin forest along the newly opened Trans Amazon Highway, Pará State, and from a single sloth, Choloepus didactylus, from near Belém, Pará. All these animals showed no symptoms of infection: isolation of the parasite was made by the inoculation of laboratory hamsters with saline suspensions of triturated liver and spleen.

Animals↗

Leishmaniasis in Brazil: X. Some observations of intradermal reactions to different trypanosomatid antigens of patients suffering from cutaneous and mucocutaneous leishmaniasis.

In spite of the difficulty of antigen standardization, paired intradermal skin tests demonstrated qualitative differences between leishmanin and in vitro exo-antigen. Some of these differences may be due to the destruction of certain antigens by phenol, while others seem to reflect basic antigenic differences. Leishmania mexicana amazonensis in vitro exo-antigen produced immediate anaphylactic reponses in 74.4% of the patients with parasitologically proven cutaneous leishmaniasis. Although more individuals responded to leishmanin, 82.4% as compared to 73.9%, the leishmanial in vitro exo-antigen gave significantly larger delayed responses, Trypanosoma cruzi trypamosomin elicited delayed reactions, while trypanosomal in vitro exo-antigen only produced immediate anaphylactic reactions in persons with active cutaneous leishmaniasis.

Animals↗