ABSTRACT
Sarcocystis neurona is the major agent of equine protozoal myeloencephalitis. It infects several mammalian species in the Americas, where the definitive hosts, marsupials of the genus Didelphis (D. virginiana and D. albiventris) are found. Domestic cats are one of the confirmed intermediate hosts of the parasite; however, antibodies against S. neurona had never before been demonstrated in Brazilian cats. The aim of this study was to determine whether cats in Bahia, Brazil, are exposed to the parasite. A total of 272 feline serum samples (134 from feral and 138 from house cats) were subjected to an indirect fluorescent antibody test using cultured merozoites of S. neurona as antigen. Positivity was detected in 4.0% (11/272) of the tested samples, with titers ranging from 25 to 800. The feline sera were also tested for antibodies against the protozoan Neospora caninum, with an observed antibody frequency of 2.9%. To the author's knowledge, this is the first study to report antibodies against S. neurona in Brazilian cats. We conclude that cats are exposed to the parasite in the region of this study. Further investigations are needed to confirm the role of cats in the transmission cycle of S. neurona in Brazil.
Sarcocystis neurona é o principal agente da mieloencefalite protozoária equina. Esse parasito infecta várias espécies de mamíferos nas Américas, onde são encontrados os hospedeiros definitivos, os marsupiais do gênero Didelphis (D. virginiana and D. albiventris). O gato doméstico é um dos hospedeiros intermediários do parasito. Contudo, anticorpos contra S. neurona ainda não tinham sido demonstrados em gatos brasileiros. O objetivo deste trabalho foi determinar se gatos da Bahia, Brasil, são expostos ao parasito. Amostras séricas de 272 felinos (134 de gatos errantes e 138 de gatos domiciliados) foram testadas pelo teste de imunofluorescência indireta, utilizando-se como antígeno, merozoítos produzidos em cultura celular. Entre as amostras testadas, 4,0% (11/272) foram positivas com títulos entre 25 e 800. Os soros dos felinos foram também testados para anticorpos contra o protozoário Neospora caninum, cuja frequência de anticorpos foi de 2,9%. Esse é o primeiro relato de anticorpos contra S. neurona em gatos brasileiros. Conclui-se que os gatos da região estudada são expostos a S. neurona. Estudos futuros são necessários, a fim de se confirmar o papel dos gatos no ciclo de transmissão de S. neurona no Brasil.
Subject(s)
Animals , Antimalarials/pharmacology , Cysteine Proteinase Inhibitors/pharmacology , Leucine/analogs & derivatives , Plasmodium falciparum/drug effects , Plasmodium falciparum/enzymology , Cysteine Endopeptidases/biosynthesis , Cysteine Endopeptidases/pharmacology , Electrophoresis, Polyacrylamide Gel , Erythrocytes/parasitology , Gene Expression Regulation, Developmental , Hydrolysis , Hemoglobins/metabolism , Leucine/pharmacology , Leupeptins/pharmacology , Plasmodium falciparum/growth & development , Time FactorsABSTRACT
The lysosomal cysteine proteinases have been found to be involved in various inflammatory conditions. Inhibitory effects of certain commonly used anti-inflammatory drugs were observed on lysosomal thiol proteinase cathepsin L. Of the non-steroidal anti-inflammatory drugs tested, phenylbutazone was found to be most potent inhibitor of cathepsin L activity. The half maximal inhibition was achieved at 0.6 mM concentration. The inhibition by phenylbutazone was of non-competitive type, with a ki of 1.3 x 10(-3) M. Flufenamic acid and indomethacin were also inhibitory to cathepsin L activity, giving half maximal inhibitions at 3.5 mM and 4.5 mM concentrations respectively. In contrast, cathepsin L activity was not affected at all by steroidal anti-inflammatory agents. Aspirin was also found to have no effect on cathepsin L activity whereas salicylic acid, its m- and p-analogs exhibited inhibitory effects but to a lesser degree.