ABSTRACT
Abstract Trypanosomiasis caused by Trypanosoma evansi can seriously affect both domestic and wild animals. This article reports on an outbreak of canine trypanosomiasis on a farm in the Pantanal region of Brazil. The farm had 38 dogs, 20 of which died before receiving veterinary care. The remaining 18 dogs were underwent anamnesisn, clinical examination, hematological and biochemical evaluations. Blood smears and PCR analysis were performed for the diagnosis. The treatment protocols used according to the clinical recovery or parasitological cure of the dogs, using diminazene diaceturate, isometamidium chloride or quinapyramine sulfate. Post-treatment parasitological evaluation was performed by the microhematocrit technique. 7/18 dogs were PCR positive for T. evansi (confirmed by sequencing). There was clinical findings, which were consistent with both the acute and chronic stages of the disease in dogs. The infected dogs all exhibited at least one clinical sign of the disease. The hematological findings were compatible with trypanosomiasis, highlighting the hypochromic microcytic anemia as the main outcome. No treatment protocol was fully effective and the prolonged use of diminazene diaceturate caused the death of an animal. The trypanosomiasis can cause high rates of morbidity and mortality in dogs and difficulty in establishment an effective and safe therapeutic protocol.
Resumo A tripanossomíase causada por Trypanosoma evansi pode acometer gravemente os animais domésticos e selvagens. Este artigo relata um surto de tripanossomíase canina em uma fazenda na região do Pantanal, Brasil. Na fazenda havia 38 cães, 20 dos quais morreram antes de receber cuidados veterinários. Os 18 cães restantes foram submetidos a anamnese, exame clínico, avaliação hematológica e bioquímica. Esfregaços de sangue e análise da PCR foram realizados para o diagnóstico. Os protocolos de tratamento foram utilizados de acordo com a recuperação clínica ou cura parasitológica dos cães, utilizando diaceturato de diminazeno, cloreto de isometamídio ou sulfato de quinapiramina. A avaliação parasitológica pós-tratamento foi realizada pela técnica de microhematócrito. 7/18 cães foram PCR positivos para T. evansi (confirmado por sequenciamento). Os achados clínicos encontrados, foram consistentes com os estágios agudo e crônico da doença em cães. Todos os cães infectados exibiram pelo menos um sinal clínico da doença. Os achados hematológicos foram compatíveis com a tripanossomíase, destacando a anemia microcítica hipocrômica como principal consequência. Nenhum protocolo de tratamento foi totalmente eficaz e o uso prolongado de diaceturato de diminazeno causou a morte de um animal. A tripanossomíase pode causar altas taxas de morbidade e mortalidade em cães e dificultar o estabelecimento de um protocolo terapêutico eficaz e seguro.
Subject(s)
Humans , Male , Female , Dogs , Phenanthridines/therapeutic use , Quinolinium Compounds/therapeutic use , Trypanosomiasis/diagnosis , Diminazene/analogs & derivatives , Dog Diseases/diagnosis , Trypanosomiasis/therapy , Trypanosomiasis/epidemiology , Brazil/epidemiology , Polymerase Chain Reaction/veterinary , Disease Outbreaks , Diminazene/therapeutic use , Dog Diseases/drug therapy , Dog Diseases/epidemiologyABSTRACT
No fully effective treatment has been developed since the discovery of Chagas' disease by Carlos Chagas in 1909. Since drug-resistant Trypanosoma cruzi strains are occurring and the current therapy is effectiveness in the acute phase but with various adverse side effects, more studies are needed to characterize the susceptibility of T. cruzi to new drugs. Many natural and/or synthetic substances showing trypanocidal activity have been used, even though they are not likely to be turned into clinically approved drugs. Originally, drug screening was performed using natural products, with only limited knowledge of the molecular mechanism involved in the development of diseases. Trans-splicing, which is unusual RNA processing reaction and occurs in nematodes and trypanosomes, implies the processing of polycistronic transcription units into individual mRNAs; a short transcript spliced leader (SL RNA) is trans-spliced to the acceptor pre-mRNA, giving origin to the mature mRNA. In the present study, permeable cells of T. cruzi epimastigote forms (Y, BOL and NCS strains) were treated to evaluate the interference of two drugs (hydroxymethylnitrofurazone - NFOH-121 and nitrofurazone) in the trans-splicing reaction using silver-stained PAGE analysis. Both drugs induced a significant reduction in RNA processing at concentrations from 5 to 12.5 æM. These data agreed with the biological findings, since the number of parasites decreased, especially with NFOH-121. This proposed methodology allows a rapid and cost-effective screening strategy for detecting drug interference in the trans-splicing mechanism of T. cruzi.