Phytomonas serpens, a tomato parasite, shares antigens with Trypanosoma cruzi that are recognized by human sera and induce protective immunity in mice.

The immune cross-reactivity between Trypanosoma cruzi, the protozoan that causes Chagas' disease, and Phytomonas serpens, a trypanosomatid that infects tomatoes, was studied. Sera from patients with Chagas' disease presented a strong reactivity with P. serpens antigens by conventional serological assays such as indirect immunofluorescence (IIF) and direct agglutination test (DAT), confirmed after cross-absorption experiments. The results show that this protozoan is highly immunogenic and that rabbit and mouse hyperimmune serum raised against T. cruzi or P. serpens was able to recognize both T. cruzi and P. serpens antigens in immunofluorescence and agglutination assays. The antigenic cross-reactivity between T. cruzi and P. serpens was also demonstrated in vivo. BALB/c mice immunized by the intraperitoneal or oral route with P. serpens and later challenged with a lethal inoculum of T. cruzi blood forms showed a significant decrease in parasitemia and increase in survival compared to controls. A practical implication of these findings is that the ingestion by humans or animals of living plant trypanosomatids present in naturally infected edible fruits could potentially prime the immune response to T. cruzi antigens and interfere with the development of T. cruzi infection.

Seropositivity for anti-trypanosoma cruzi antibodies among blood donors of the "Hospital Universitário Regional do Norte do Paraná", Londrina, Brazil

The most frequent form of acquisition of Chagas' disease in endemic areas was the transmission through the feces of contaminated triatominae. However, special attention should be paid in urban areas to transmission by blood transfusion, justifying the compulsory screening of blood donors. Early investigations at blood banks in the town of Londrina, Brazil, demonstrated that the seroprevalence of anti-Trypanosoma cruzi antibodies among blood donors was approximately 7.0 in the fifties. Further studies demonstrated practically the same seroprevalence until the eighties. In an attempt to obtain data about the real dimension of the seropositivity for anti-Trypanosoma cruzi antibodies in the region, the authors carried out a large-scale study on 45,774 serum samples from blood donors of the Hemocentro of Hospital Univesitário Regional do Norte do Paraná (HURNP), Universidade Estadual de Londrina. The immunological tests were done at the Division of Clinical Immunology of HURNP from May 1990 to December 1994. The serum samples were studied by the indirect hemagglutination assay (IHA, using kits commercially obtained from EBRAM) and by indirect immunofluorescence (IFI, using kits from LIO SERUM) with anti-human IgG conjugate (LABORCLIN). The results demonstrated that 643 serum samples were positive in both assay corresponding to a seroprevalence of 1.4, i.e., a significant decrease in anti-Trypanosoma cruzi antibodies in the region in comparison with the previously mentioned rates. Data correlating sex and age of seropositive blood donors are presented, as well as the possible factors that may have contributed to the results observed.

Soroaglutinação para brucelose humana em populações profissionalmente expostas no norte do Paraná e Jaguaruana Ceara / Soroaglutinação para brucelose humana em populações profissionalmente expostas no norte do Paraná e Jaguaruana Ceara

Tube, plate and card serum agglutination tests for human brucellosis were applied to 1.662 serum samples from workers in slaughter houses and rural populations from the North of Parana and from Cearâ (Brazil). The results showed mean prevalence rates of 5% for slaugher house workers and 2,2% for rural populations of Parana, J 1,4% for in intrabitants of artificially irrigated areas and 9,1% for populations in the Ceará state. The sex distribution of agglutination tests was 7,6% in males and 3,4% in females in Parana while the incidence was practically equal in both sexes (10,6% in males and 10, 7% in females) in Ceará. The presence of positive tests in young children and in females permit us to characterize human bmcellosis as alimentary transmission disease in Ceará while presents professional disease characteristics in Parana.

A soroaglutinação para brucelose humana em tubo, em placa e o "Card-test" foi aplicada a 1662 amostras de soro procedentes de trabalhadores em frigoríficos e de populações rurais do Norte do Paraná e do Estado do Ceará. Os resultados mostraram índices de prevalência médios de 5% para trabalhadores em frigoríficos e 2,2% para populações rurais do Paraná. No Estado do Ceará, a prevalência média foi de 11,2% para habitantes de perímetros irrigados com atividade agropecuária e de 9,1% para populações rurais. A distribuição por sexo, no Paraná, indicou 7,6% de reagentes no masculino e 3,4% no feminino, enquanto no Ceará, a prevalência foi praticamente igual nos dois sexos (10,6% no masculino e 10,7% no feminino). Reações positivas em crianças de tenra idade e em mulheres permitem caracterizar a brucelose humana como doença de transmissão essencialmente alimentar nas populações analisadas no Estado do Ceará, enquanto apresenta características de doença profissional no Paraná.

Soroaglutinação para brucelose humana em populações profissionalmente expostas no norte do Paraná e Jaguaruana Ceara / Soroaglutinação para brucelose humana em populações profissionalmente expostas no norte do Paraná e Jaguaruana Ceara

Tube, plate and card serum agglutination tests for human brucellosis were applied to 1.662 serum samples from workers in slaughter houses and rural populations from the North of Parana and from Cearâ (Brazil). The results showed mean prevalence rates of 5% for slaugher house workers and 2,2% for rural populations of Parana, J 1,4% for in intrabitants of artificially irrigated areas and 9,1% for populations in the Ceará state. The sex distribution of agglutination tests was 7,6% in males and 3,4% in females in Parana while the incidence was practically equal in both sexes (10,6% in males and 10, 7% in females) in Ceará. The presence of positive tests in young children and in females permit us to characterize human bmcellosis as alimentary transmission disease in Ceará while presents professional disease characteristics in Parana.

A soroaglutinação para brucelose humana em tubo, em placa e o "Card-test" foi aplicada a 1662 amostras de soro procedentes de trabalhadores em frigoríficos e de populações rurais do Norte do Paraná e do Estado do Ceará. Os resultados mostraram índices de prevalência médios de 5% para trabalhadores em frigoríficos e 2,2% para populações rurais do Paraná. No Estado do Ceará, a prevalência média foi de 11,2% para habitantes de perímetros irrigados com atividade agropecuária e de 9,1% para populações rurais. A distribuição por sexo, no Paraná, indicou 7,6% de reagentes no masculino e 3,4% no feminino, enquanto no Ceará, a prevalência foi praticamente igual nos dois sexos (10,6% no masculino e 10,7% no feminino). Reações positivas em crianças de tenra idade e em mulheres permitem caracterizar a brucelose humana como doença de transmissão essencialmente alimentar nas populações analisadas no Estado do Ceará, enquanto apresenta características de doença profissional no Paraná.