Hemoculture and Polymerase Chain Reaction Using Primers TCZ1/TCZ2 for the Diagnosis of Canine and Feline Trypanosomiasis

Introduction. American trypanosomiasis, also known as Chagas disease, is a zoonosis caused by Trypanosoma cruzi (T. cruzi). Dogs and cats participate actively in this parasite's transmission cycle. This study aimed at evaluating the occurrence of T. cruzi in dogs and cats from Botucatu, SP, Brazil, as well as at evaluating the technique of hemoculture in LIT (liver infusion tryptose) medium by polymerase chain reaction (PCR). Methods. Blood samples were collected from 50 dogs and 50 cats in Botucatu-SP, Brazil. For hemoculture, the samples were inoculated in LIT medium, and readings were performed for four months. Upon completion of such period, all the hemocultures were processed for parasitic DNA extraction. The PCR reactions were performed by using primers TCZ1/TCZ2. Results. Ten dogs and ten cats (20%) were positive to PCR, and four dogs and three cats (7%) were positive to hemoculture. Only in a one cat sample (1%) there was confirmation of positive hemoculture by PCR for T. cruzi. Conclusions. Results showed that PCR was a suitable tool for the confirmation of the parasite detection in hemoculture samples, and that dogs and cats from Botucatu, SP, Brazil, are maintaining the role of household reservoirs of T. cruzi, which reinforces the need for constant epidemiologic surveillance for this zoonosis. 1. Introduction American trypanosomiasis, also known as Chagas disease (CD), is an important zoonosis, and its etiologic agent is the flagellate protozoan Trypanosoma cruzi (T. cruzi) [1]. In Brazil, according to serological survey carried out between 2001 and 2008 in all states, it is estimated that approximately 133,000 people are infected with T. cruzi [2]. Originally, American trypanosomiasis was an enzootic disease as it affected only wild mammals. Today, T. cruzi has been detected also in domestic mammals such as dogs and cats, thus making trypanosomiasis a typical zoonosis [3]. Dogs and cats infected with T. cruzi act as infection sources for humans and other animals, thus being important reservoirs of trypanosomatids among household animals [4]. Hemoculture, which consists in the enrichment of a blood sample, thus enabling the multiplication of existing parasites, represents an indirect parasitological test used in the chronic phase of CD. Positive hemoculture, when utilized for diagnose, shows the presence of the parasite in the blood stream. This is a limitation of the hemoculture technique when it is compared at polymerase chain reaction (PCR) technique, which can detect parasite fragments and does not require the presence of whole organisms