Virulence of Trypanosoma cruzi from vector and reservoir in in natura açaí pulp resulting in food-borne acute Chagas disease at Pará State, Brazil.

BACKGROUND: In recent decades some outbreaks of food-borne acute Chagas disease (ACD) in humans were identified by clinical and epidemiological characterization after association through the ingestion of açaí pulp probably contaminated with Trypanosoma cruzi. Whereas Belém and Abaetetuba stood out as important risk regions for disease transmission, the importance of Rhodnius pictipes, and Philander opossum for the biological cycle of T. cruzi, and data from agribusiness market of açaí, to study T. cruzi from vector and reservoir of the Brazilian Amazon region is critical for this context. Thus, the purpose of this study was to verify the infective capacity and the virulence of T. cruzi in açaí pulp from vector and reservoir at Pará State experimentally. METHODS: 105T. cruzi I in in natura açaí pulp from Belém at Pará State, at room temperature, after forced sieving, by intraperitoneal, gavage or oral route of inoculation in B6.129S7Rag1-/-tmMom/J Unib allowed food-borne ACD analysis using common light microscopy. PRINCIPAL FINDINGS: T. cruzi in in natura açaí pulp from R. pictipes (Val-De-Cans Forest, Belém, and Ajuaí River, Abaetetuba, Pará), and P. opossum (Combu Island, Belém, Pará) caused ACD and death between 17 and 52 days after experimental infections in murine immunodeficient hosts. CONCLUSIONS: T. cruzi from different sources and locations at Pará State in in natura açaí pulp retained its infective capacity and virulence, and can cause new outbreaks of ACD by oral transmission. Additionally, quality basic education will facilitate efficient hygiene practices throughout the açaí productive chain can eradicate food-borne ACD in the coming decades.

The Contribution of Nicotinamide Nucleotide Transhydrogenase to Peroxide Detoxification Is Dependent on the Respiratory State and Counterbalanced by Other Sources of NADPH in Liver Mitochondria.

The forward reaction of nicotinamide nucleotide transhydrogenase (NNT) reduces NADP(+) at the expense of NADH oxidation and H(+) movement down the electrochemical potential across the inner mitochondrial membrane, establishing an NADPH/NADP(+) ratio severalfold higher than the NADH/NAD(+) ratio in the matrix. In turn, NADPH drives processes, such as peroxide detoxification and reductive biosynthesis. In this study, we generated a congenic mouse model carrying a mutated Nnt(C57BL/6J) allele from the C57BL/6J substrain. Suspensions of isolated mitochondria from Nnt(+/+), Nnt(+/-), and Nnt(-/-) mouse liver were biochemically evaluated and challenged with exogenous peroxide under different respiratory states. The respiratory substrates were also varied, and the participation of concurrent NADPH sources (i.e. isocitrate dehydrogenase-2, malic enzymes, and glutamate dehydrogenase) was assessed. The principal findings include the following: Nnt(+/-) and Nnt(-/-) exhibit ∼50% and absent NNT activity, respectively, but the activities of concurrent NADPH sources are unchanged. The lack of NNT activity in Nnt(-/-) mice impairs peroxide metabolism in intact mitochondria. The contribution of NNT to peroxide metabolism is decreased during ADP phosphorylation compared with the non-phosphorylating state; however, it is accompanied by increased contributions of concurrent NADPH sources, especially glutamate dehydrogenase. NNT makes a major contribution to peroxide metabolism during the blockage of mitochondrial electron transport. Interestingly, peroxide metabolism in the Nnt(+/-) mitochondria matched that in the Nnt(+/+) mitochondria. Overall, this study demonstrates that the respiratory state and/or substrates that sustain energy metabolism markedly influence the relative contribution of NNT (i.e. varies between nearly 0 and 100%) to NADPH-dependent mitochondrial peroxide metabolism.

Virulence of Trypanosoma cruzi in Açai ( Euterpe oleraceae Martius) Pulp following Mild Heat Treatment.

Outbreaks of acute Chagas disease (ACD) in northern Brazil can be caused by the ingestion of unprocessed açai pulp contaminated with Trypanosoma cruzi . The aim of this study was to determine the minimum thermal process required to inactivate T. cruzi in açai pulp. Trypomastigotes (100,000) of T. cruzi Y strain were added to 0.15 M NaCl or açai pulp and continuously mixed while being heat treated at 37 to 49°C for up to 1 h. When necessary, parasites were separated from açai pulp by forced sieving. Inocula were administrated intraperitoneally in inbred immunodeficient C.B-17-Prkdcscid/Pas Unib mice, and the recipients were monitored for parasitemia and mortality. Mice received prophylactic antibiotic therapy by using cephalexin to prevent bacterial infection from the açai pulp. T. cruzi retained its virulence in 0.15 M NaCl and açai pulp at 44 ± 0.1°C for 10 min and at 43 ± 0.1°C for 20 min, respectively, causing ACD and death in mice up to 24 days after infection. Incubation of açai pulp inoculum above 43°C for 20 min neutralized T. cruzi virulence, thereby preventing ACD and death in murine recipients. The heating of açai pulp above 43°C for 20 min is a practical and effective measure to prevent foodborne ACD caused by T. cruzi .

Sobrevivência e infectividade do Trypanosoma cruzi na polpa de açaí: estudo in vitro e in vivo / Survival and infectivity of Trypanosoma cruzi in açaí pulp: in vitro and in vivo study

Objetivo: estudar a sobrevivência e a infectividade de Trypanosoma cruzi na polpa de açaí. Métodos: foram realizados experimentos in vitro e in vivo. Alíquotas de polpa provenientes da cidade de Belém (capital do estado do Pará, região Norte do Brasil) foram misturadas a 105 tripomastigotas e mantidas às temperaturas ambiente, 4°C e -20°C, com diferentes períodos de incubação; posteriormente, os parasitos foram isolados e inoculados em camundongos imunodeficientes C.B-17-Prkdcscid/PasUnib pelas vias intraperitoneal, oral ou gavagem. Resultados: todas as vias foram eficientes. Houve retardo de 5 dias no início da parasitemia na infecção oral. À temperatura ambiente por 48 horas, a polpa preservou a virulência do parasito. Refrigeração a 4°C por 144 horas e congelamento a -20°C por 26 horas não eliminaram o parasito. Conclusão: os testes sugerem a possibilidade de os surtos de doença de Chagas aguda no Norte do Brasil estarem relacionados ao consumo de polpa de açaí.

Objective: to evaluate infectivity by Trypanosoma cruzi and its survival in açaí pulp. Methods: experiments were performed in vitro and in vivo; aliquots of pulp from Belém City (capital of the state of Pará, Northern Region of Brazil) were mixed with 105 trypomastigotes, and maintained at room temperature, and at temperatures of 4°C and -20 °C, within different incubation periods; following that, the parasites were isolated and inoculated into immunodeficient mice CB-17-Prkdcscid/PasUnib, by intraperitoneal, oral, orgavage routes. Results: all routes showed effectiveness. There was a delay of 5 days in the beginning of the parasitemia by oral infection; the pulp at room temperature for 48h kept the parasite virulence preserved. Keeping the samples cooled at 4ºC during 144h and the freezing at -20°C for 26h did not kill the parasite. Conclusion: tests suggest that açaí pulp consumption may be related to outbreaks of acute Chagas' disease in Northern Brazil.

Survival in vitro and virulence of Trypanosoma cruzi in açaí pulp in experimental acute Chagas disease.

Chagas disease is a parasitic infection with high socioeconomic impact throughout Latin America. Although this severe, incurable disease can be transmitted by several routes, oral transmission is currently the most important route in the Amazon Basin. Açaí pulp has nutritional properties and is popular throughout Brazil and abroad. However, this pulp has been associated with microepidemics of acute Chagas disease (ACD) in northern Brazil, where açaí fruit is the main food supplement. In this study, we examined the in vitro survival and in vivo virulence of Trypanosoma cruzi Y strain in açaí pulp. Aliquots of in natura açaí pulp produced in Belém city in the northern Brazilian state of Pará were mixed with 105 trypomastigotes. The samples were incubated at room temperature or at 4 or -20°C for various periods, and the parasites were isolated by forced sieving. The resulting eluates were examined by microscopy, and the trypomastigotes were administered intraperitoneally, orally, or by gavage to immunodeficient mice (C.B-17-Prkdc(scid)/PasUnib) that had been pretreated with antibiotics. Parasitemia was quantified by the Brener method, and mortality was recorded daily. All routes of administration resulted in ACD. A 5-day delay in the onset of parasitemia occurred with oral administration. The survival and virulence of the parasites were unaffected by prior incubation at room temperature for 24 h, at 4°C for 144 h, and at -20°C for 26 h. These results indicate that T. cruzi can survive and retain its virulence in açaí pulp under various conditions and that cooling and freezing are not suitable methods for preventing foodborne ACD.

Increased cavernosal relaxations in sickle cell mice priapism are associated with alterations in the NO-cGMP signaling pathway.

INTRODUCTION: Priapism is defined as prolonged and persistent penile erection, unassociated with sexual interest or stimulation, and is one of the many serious complications associated with sickle cell disease (SCD). AIM: The aim of this study was to evaluate the role of the NO-cGMP signaling pathway in priapism in Berkeley murine model of SCD (SS). METHODS: SS mice and C57BL/6 mice (control) penile tissues were removed and the erectile tissue within the corpus cavernosum (CC) was surgically dissected free. The strips were mounted in 10 mL organ baths containing Krebs solution at 37 degrees C (95% O(2), 5% CO(2), pH 7.4), and vertically suspended between two metal hooks. MAIN OUTCOME MEASURES: Cumulative concentration-response curves were constructed for acetylcholine (ACh; endothelium-dependent responses), sodium nitroprusside (SNP; endothelium-independent relaxations) and BAY 41-2272 (a potent activator of NO-independent site of soluble guanylate cyclase) in CC precontracted with phenylephrine. Cavernosal responses induced by frequency-dependent electrical field stimulation (EFS) were also carried out to evaluate the nitrergic cavernosal relaxations. RESULTS: In SS mice, ACh-induced cavernosal relaxations were leftward shifted by 2.6-fold (P < 0.01) that was accompanied by increases in the maximal responses (78 +/- 5% and 60 +/- 3% in SS and C57B6/6J mice, respectively). Similarly, SNP- and BAY 41-2272-induced CC relaxations were leftward shifted by approximately 3.3- and 2.2-fold (P < 0.01) in SS mice, respectively. A significant increase in maximal responses to SNP and BAY 41-2272 in SS mice was also observed (113 +/- 6% and 124 +/- 5%, respectively) compared with C57B6/6J mice (83 +/- 4% and 99 +/- 2%, respectively). The EFS-induced cavernosal relaxations were also significantly higher SS mice. CONCLUSION: These results showed that SS mice exhibit amplified corpus carvenosum relaxation response mediated by NO-cGMP signaling pathway. Intervention in this signaling pathway may be a potential therapeutic target to treat SCD priapism.

Uso do monossulfeto de tetraetiltiuram no tratamento de ectoparasitas em camundongos / Use of tetraethylthiuram monosulfide in the treatment of ectoparasites in mice

Casais de camundongos isogênicos das raças CBA, BALB/c e machos e fêmeas de Swiss heterogenéticos criados no sistema convencional, que se encontravam infectados em diferentes graus por Myobia musculi e Myocoptes musculinus, foram submetidos a quatro esquemas de tratamento com Tetmosol. A incidência de ectoparasitas na raça C57BL/10 foi apenas 1,2%. Todos os animais da raça CBA e Swiss encontravam-se parasitados, enquanto que a infestaçäo do BALB/c foi de 50 a 90%. Os melhores resultados dos 4 esquemas de tratamento testados foram observados utilizando-se Tetmosol na concentraçäo 2,5% em banhos seriados com intervalos alternados de 3 e 4 dias, num período de 21 dias. A incidência de ectoparasitas adultos em CBA, BALB/c e Swiss após o tratamento foi de respectivamente 0%, 40% e 0%, enquanto que para ovos viáveis os repectivos resultados foram de 20%, 50% e 0%. Após a introduçäo de matrizes tratadas num sistema de criaçäo sob barreiras, a colônia tem sido examinada sistematicamente há 24 meses e encontra-se isenta de ectoparasitas