José Oswaldo Costa

Neutralizing potency of horse antibothropic antivenom. Correlation between in vivo and in vitro methods

The correlation coefficients between in vivo neutralization of lethal toxicity (ED50), neutralization of the hemolytic activity (PLA2) and levels of antibodies measured by ELISA, was investigated to test the potency of horse anti-bothropic antivenom. Twenty six horses were hyperimmunized with Bothrops venoms (B. alternatus, B. jararaca, B. jararacussu, B. neuwiedii and B. moojeni). To set up an indirect ELISA, for neutralization of PLA2 activity and for determination of ED50 in Swiss mice, the whole Bothrops jararaca venom (reference venom for assessing the bothropic antivenom potency in Brazil) was used. The toxic fraction (purified from B. jararaca venom by Sephadex G-100 chromatography) was also used as antigen for ELISA. All antivenoms analyzed effectively neutralized the lethal activity in the range of 1.6 to 9.6 mg/ml of antivenom. The correlation coefficient between ED50 and ELISA antibody titers against the crude venom and toxic fraction was r = 0.65 (P < 0.001) and r = 0.85 (P < 0.0001), respectively. Correlation between ED50 and neutralization of PLA2 activity was r = 0.52 (P < 0.01), and the correlation between ELISA antibody titers and neutralization of PLA2 activity was r = 0.58 (P < 0.002). Thus, the ELISA which measures only the antibody against the major toxic fraction of the B. jararaca venom should be most suitable for use as an in vitro assay of bothropic antivenom potency.

Therapy of Human African Trypanosomiasis: Current Situation

This paper is a review of the current situation of the treatment of human African trypanosomiasis. The existing approved drugs are old, toxic and/or expensive. Therapeutic failures are common. Several factors may contribute to the problems of chemotherapy, including differences in the epidemiology of the disease, difficulties in the diagnosis and staging of the infection, availability, distribution and pharmacologic properties of drugs, standardization of treatment regimens, response to therapy, follow-up period, and relapses and clinical trials. The new therapeutic approaches include the development and approval of new drugs, the use of new therapeutic regimens, the study of drug combinations, and the development of new formulations.

Control of schistosomiasis mansoni in ravena (Sabará, State of Minas Gerais, Brazil) through Water supply and quadrennial treatments

In this study, the results obtained in a control programme of schistosomiasis in Ravena (Sabará, Minas Gerais) between 1980 and 1992 are evaluated. Control measures used in this programme were: specific treatment of the people infected with Schistosoma mansoni at four year-intervals (1980/84/88) and the supply of tap water to 90% of the residences in 1980. A significant reduction of the prevalence (36.7% to 11.5%, p < or = 0.05) and of the intensity of the infection (228.9 eggs per gram of feces (epg), s = 3.7 to 60.3 epg, s = 3.5, p < or = 0.05) was observed. No cases of the severe form of the disease were diagnosed in the area. Factors independently associated with the infection were in 1980 daily sand extraction and the lack of tap water in residences and in 1992 daily sand extraction and fishing and weekly swimming. Concluding, the supply of tap water together with quadrennial treatments significantly diminished both the prevalence and intensity of the S. mansoni infection, with the additional gain of persistent low indices even after four-year intervals between the treatments.

Atividade antimicrobiana de bactérias lácticas de embutidos curados frente a Listeria monocytogenes

The direct antimicrobial activity of 336 samples of lactic acid bacteria, isolated from Brazilian dry fermented sausages, was evaluated in vitro against two strains of Listeria monocytogenes, using agar diffusion assay. A total of 108 strains of lactic acid bacteria showed direct inhibitory activity against at least one of the two strains of Listeria monocytogenes, probably due to production of organic acids, hydrogen peroxide, and oxygen metabolites, in addition to other substances. These 108 strains were further tested for indirect antimicrobial activity against the same strains of Listeria monocytogenes, as well as against other strains of lactic acid bacteria. Indirect antimicrobial activity was evaluated using free-cells supernatants, obtained through sterilization by microfiltration. These supernatants were treated to eliminate inhibitory substances, such as organic acids, and hydrogen peroxide by adjusting the pH and liofilization. A total of eight strains of lactic acid bacteria had indirect antimicrobial activity against a least one of the indicator microorganisms. This indirect antimicrobial activity is indicator of substance similar to bacteriocins. Three of these eight strains were characterized and identified as Lactobacillus sp.

Activity of 9-acridanone-hydrazone drugs detected at the pre-postural phase, in the experimental schistosomiasis mansoni

The compound Ro-15.5458/000, derivative in the class of 9-acridanone-hydrazones, was found to be effective against Schistosoma mansoni in mice, killing almost all the skin schistosomules (24 hr after infection), when administered at the dose of 100 mg/kg. In experiments carried out with Cebus monkeys, the drug was shown to be fully effective at 25 mg/kg, 7 days after infection. These data, associated with the good results obtained earlier at the post-postural phase of schistosomiasis, allow the inference that this promising compound may be important in the set of antischistosomal drugs, depending on further toxicological and clinical tests.

The life cycle of Dendritobilharzia anatinarum cheatum, 1941 (Trematoda, Schistosomatidae)

The life cycle of Dendritobilharzia anatinarum was completed experimentally in the laboratory. Cairina moschata domestica (domestic duck) and Biomphalaria straminea served respectively as definitive and intermediate hosts. Eggs passed in duck faeces hatch miracidia in 10 minutes when placed in water. Eight days after the snail infection, the mother sporocyst contains daughter sporocysts ready to migrate. Cercariae are present within the daughter sporocysts 23 days after infection and emerge from the snail on the 25th day. They actively penetrate the skin of the duck and after a prepatent of 39 days, sexually mature trematodes are present in the blood vessels of the bird. The adult parasite is predominantly in the renal-portal system and to a lesser degree in the lungs and mesentery. A detailed morphological description of the egg. miracidium, sporocyst and cercaria is presented.

Prevalência de anticorpos anti-Rickettsia spp. em cães da cidade de Belo Horizonte, MG

ABSTRACT A cross-sectional study was conducted to determine the seroprevalence of anti- Rickettsia spp. in dogs from Belo Horizonte, MG. For this purpose, serum samples from 453 dogs were collected during the rabies vaccination campaign and tested by the indirect immunofluorescence assay (IFA) using five antigens: Rickettsia bellii , Rickettsia amblyommii , Rickettsia rickettsii , Rickettsia parkeri , and Rickettsia felis. The endpoint titer reacting with each antigen was determined and serum was considered positive if it reacted at the 1:64 dilution. Serum showing titer for a Rickettsia species at least four-fold higher than that observed for any other Rickettsia species was considered homologous to the first Rickettsia species. Only three (0.66%) dogs reacted positively to at least one Rickettsia species and one serum showed to be homologous to R. rickettsii. These results showed a low prevalence of antibodies anti- Rickettsia spp. in dogs from Belo Horizonte city. However, other serosurvey needs to be performed for surveillance of the endemic status of the disease in the municipal district. Keywords: dog,A cross-sectional study was conducted to determine the seroprevalence of anti-Rickettsia spp. in dogs from Belo Horizonte, MG. For this purpose, serum samples from 453 dogs were collected during the rabies vaccination campaign and tested by the indirect immunofluorescence assay (IFA) using five antigens: Rickettsia bellii, Rickettsia amblyommii, Rickettsia rickettsii, Rickettsia parkeri, and Rickettsia felis. The endpoint titer reacting with each antigen was determined and serum was considered positive if it reacted at the 1:64 dilution. Serum showing titer for a Rickettsia species at least four-fold higher than that observed for any other Rickettsia species was considered homologous to the first Rickettsia species. Only three (0.66%) dogs reacted positively to at least one Rickettsia species and one serum showed to be homologous to R. rickettsii. These results showed a low prevalence of antibodies anti-Rickettsia spp. in dogs from Belo Horizonte city. However, other serosurvey needs to be performed for surveillance of the endemic status of the disease in the municipal district.

Prevalence of antibodies anti-Rickettsia in dogs from Belo Horizonte, MG, Brazil

ABSTRACT A cross-sectional study was conducted to determine the seroprevalence of anti- Rickettsia spp. in dogs from Belo Horizonte, MG. For this purpose, serum samples from 453 dogs were collected during the rabies vaccination campaign and tested by the indirect immunofluorescence assay (IFA) using five antigens: Rickettsia bellii , Rickettsia amblyommii , Rickettsia rickettsii , Rickettsia parkeri , and Rickettsia felis. The endpoint titer reacting with each antigen was determined and serum was considered positive if it reacted at the 1:64 dilution. Serum showing titer for a Rickettsia species at least four-fold higher than that observed for any other Rickettsia species was considered homologous to the first Rickettsia species. Only three (0.66%) dogs reacted positively to at least one Rickettsia species and one serum showed to be homologous to R. rickettsii. These results showed a low prevalence of antibodies anti- Rickettsia spp. in dogs from Belo Horizonte city. However, other serosurvey needs to be performed for surveillance of the endemic status of the disease in the municipal district. Keywords: dog,A cross-sectional study was conducted to determine the seroprevalence of anti-Rickettsia spp. in dogs from Belo Horizonte, MG. For this purpose, serum samples from 453 dogs were collected during the rabies vaccination campaign and tested by the indirect immunofluorescence assay (IFA) using five antigens: Rickettsia bellii, Rickettsia amblyommii, Rickettsia rickettsii, Rickettsia parkeri, and Rickettsia felis. The endpoint titer reacting with each antigen was determined and serum was considered positive if it reacted at the 1:64 dilution. Serum showing titer for a Rickettsia species at least four-fold higher than that observed for any other Rickettsia species was considered homologous to the first Rickettsia species. Only three (0.66%) dogs reacted positively to at least one Rickettsia species and one serum showed to be homologous to R. rickettsii. These results showed a low prevalence of antibodies anti-Rickettsia spp. in dogs from Belo Horizonte city. However, other serosurvey needs to be performed for surveillance of the endemic status of the disease in the municipal district.

Melophagus ovinus e Trypanosoma (Megatrypanum) melophagium em ovinos no Estado de Minas Gerais, Brasil

Melophagus ovinus is identified for the first time in Minas Gerais State and Trypanosoma (Megatrypanum) melophagium in Brazil.

Melophagus ovinus and Trypanosoma (Megatrypanum) melophagium in ovines in the State of Minas Gerais, Brasil

Melophagus ovinus is identified for the first time in Minas Gerais State and Trypanosoma (Megatrypanum) melophagium in Brazil.