Cats and dogs are hosts of a large number of gastrointestinal parasites and can shed helminth eggs and protozoan oocysts in their feces. The close relationship between companion animals and humans intensifies human exposure to zoonosis caused by parasites. In this study, 177 fecal samples were collected: 128 from dogs and 49 from cats of both sexes and varied ages. One or more intestinal parasites were observed in 56.2% (72/128) of the dog fecal samples and in 53.0% (26/49) of the cat fecal samples. Parasitic monoinfection was present in 70.8% (51/72) of dog samples and in 46.1% (12/26) of cat samples, whereas multi-infection was observed in 29.2% (21/72) and 53.8% (14/26) of dog and cat samples, respectively. The detection frequency of Cryptosporidium spp. was 22.6% (40/177) using Ziehl-Neelsen staining. DNA was extracted from all samples and the Cryptosporidium small subunit ribosomal ribonucleic acid (SSU rRNA) gene was amplified from 5.6% (10/177) of the fecal samples using nested polymerase chain reaction (PCR). Amplification was achieved in 4.6% (6/128) of the dog samples and in 8.2% (4/49) of the cat samples. DNA sequencing of the nested PCR positive samples identified Cryptosporidium canis in 66.6% (4/6) and Cryptosporidium parvum in 33.3% (2/6) of the dog samples and Cryptosporidium felis in 75% (3/4) and Cryptosporidium parvum in 25% (1/4) in the cat samples. The present study thus demonstrated significant levels of gastrointestinal parasite infection in companion animals and highlighted the presence of zoonosis agents.

Infections caused by protozoa belonging to the (17/80,.2) of the tested samples and T. gondii DNA in 15% (12/80,. Moreover, 6.2% (5/80,) samples contained DNA of both protozoan. The presence of N. caninum nucleic acids was not observed in tested samples. However, 21,2% (17/80, IC: 12,2) das amostras testadas e DNA de T. gondii em 15% (12/80, IC: 7,8). Em 6,2% (5/80, IC: 2,[1][2][3][4][5][6][7][8][9][10][11][12][13]9), foram detectados DNA de ambos os protozoários. Todas as amostras positivas no PCR (23, IC: 14,1)

This study describes experimental infection of guinea pigs (Cavia porcellus) infested with naturally infected Amblyomma ovale nymphs with Rickettsia sp. (Atlantic rainforest strain), and the capacity of A. ovale nymphs to transmit this bacterium. Twenty-six guinea pigs were divided into the following groups: G1, 10 animals infested with uninfected A. ovale nymphs; G2, 10 animals infested with nymphs infected with Rickettsia sp. (Atlantic rainforest strain); and G3, 6 animals without tick infestation. Blood samples were taken 7, 14, 21, and 28 days post-infestation for serological and hematological tests. For histopathological analysis and rickettsial DNA detection, fragments of the spleen, lung, brain, and liver were harvested after euthanasia. The average feeding period for nymphs was 6.6 days for G1 and 6 days for G2. Hemolymph and PCR assays, performed to detect the causative agent in ticks, indicated that in G1, all ticks were negative, and in G2, all nymphs were positive by PCR and 80% (8/10) was positive by hemolymph tests. The only clinical change was skin scarring at the tick attachment site. Hematological parameters indicated leukopenia and total plasma protein (TPP) increased with decreased platelets in G1. In G2, leukocytosis, neutrophilia, monocytosis, an increase in platelets, and reduced TPP were observed. Only G2 guinea pigs were seroconverted (80%; 8/10). Histopathology tests indicated mild, diffuse hemosiderosis and mild, multifocal, follicular hyperplasia in the spleen. Molecular analysis did not detect Rickettsia sp. DNA in C. porcellus tissues. We demonstrated the capacity of A. ovale nymphs to transmit Rickettsia sp. (Atlantic rainforest strain) to guinea pigs.

Reproductive tests in cattle are of great economic importance, given the impact it can have on the production system and may be caused by agents. Neospora caninum and Bovine Viral Diarrhea virus (BVDV) are considered of great importance as reproductive and should be considered responsible for keeping animals persistently infected. The present study included 479 calf serum samples for export in the state of Rio Grande do Sul (RS). All samples were screened for BVDV by an ELISA antigen. BVDV antigen-positive ELISA samples were isolated from BVDV in cell culture. An indirect immunofluorescence (IFT) technique was used to detect anti-N. caninum antibodies. Of the 479 export-treated serum samples, 361 were positive for BVDV antigens by ELISA and/or viral isolation test (361/479-75.36%), and 109 IFT-positive samples for N. caninum (109/479-22.75%). Despite detection of antibodies anti-N. caninum did not differ statistically between naturally infected BVDV and non-BVDV infected animals suggesting that there is no interference of BVDV infection on infection or detection rate of animals with N. caninum, positive animals in viral isolation and high DO in BVDV-Ag ELISA. may present active disease and consequent immunosuppression, contributing to a potential reactivation of N. caninum.

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