Revista Brasileira De Parasitologia Veterinaria最新文献

In this study, an evaluation was made of three treatments against feline leishmaniosis (FeL) and their impacts on the transmission of Leishmania infantum to its vector, Lutzomyia longipalpis. A cat with clinical signs of FeL was examined and L. infantum diagnosed. Subsequently, the cat was subjected to xenodiagnosis and L. infantum detected in the vectors. The cat was then treated with three different drugs and the clinical improvement and parasite transmissibility to the vector were evaluated. Promastigotes were observed in 21/52 female sandflies (40.38%) in a xenodiagnosis prior to the treatments. Clinical signs persisted after the first treatment with marbofloxacin, and the cat remained positive in serological, molecular, and parasitological tests. Therefore, the cat was treated with miltefosine but remained sick and tested positive. A second xenodiagnosis was performed a month after treatment with miltefosine, and promastigotes were observed in 5/9 females (55.55%). Lastly, the cat was treated with allopurinol, which led to good clinical improvement, but it remained positive, and a final xenodiagnosis revealed Leishmania in 2/29 (6.89%) females. The results showed that only treatment with allopurinol produced a good clinical response, but none of the treatments succeeded in eliminating L. infantum infection or preventing transmission to the vector.

A complex interaction of gastrointestinal parasites with sheep hosts may involve bacteria communities, parasite genera, parasitic genes, and biological pathways. Haemonchus contortus presents a global challenge for ruminants, and the bacterial community can influence sheep's resistance and susceptibility to these parasites. Thus, a better understanding of this complex interaction could contribute to the development of a new approach to parasite control. This study evaluated the bacterial community of Corriedale sheep naturally infected with H. contortus based on the fecal egg counts over ten months and then classified as having low (LC), intermediate (IC), or high (HC). Stool samples were collected monthly for egg counts (EPG), and 16S rRNA gene sequencing was performed on five animals from each group. The average EPG was 2,635 ± 105 for HC, 845 ± 129 for IC, and 110 ± 70 for LC, with a significant difference (p = 0.0001). Firmicutes, Proteobacteria, and Spirochaetes were more abundant in the HC group. 102 bacterial genera showed significant differences between the LC and HC groups. Beta diversity was statistically different (p<0.005) for HC compared with the other two groups; also, different communities were found between LC and HC. Sediminispirochaeta, Oribacterium, Alloprevotella, Prevotellaceae_UCG-001, Prevotellaceae_UCG-003, Ruminiclostridium_6 and Ruminococcus_1were significant more abundant in LC, and IC group. Acetobacter and Methanocorpusculum had a significant reduction in the LC group. Thus, bacterial genera related to low methane emission and food efficiency were significantly present in the LC group. Therefore, a better understanding of the role of host-bacterial community-parasite interaction could contribute to improving parasite control management.

This study investigated infection by Leishmania spp., Leptospira spp., Toxoplasma gondii, and Trypanosoma cruzi in six-banded armadillos (Euphractus sexcinctus) from the semiarid region of northeastern Brazil. Twenty specimens of E. sexcinctus were captured alive by wildlife veterinarians from their natural habitats in different locations. The animals were euthanized following induction of anesthesia, and different biological samples were collected. Infection with four pathogens was subsequently evaluated: Leishmania infection was investigated by spleen and liver Polymerase Chain Reaction (PCR); Leptospira spp. infection was evaluated by kidney PCR and serologically by microscopic agglutination test; T. gondii infection was assessed by PCR of the heart, lung, and spleen; and T. cruzi infection was investigated by heart and whole blood PCR and hemoculture. All tests presented negative results apart from whole blood PCR to detect T. cruzi, which was positive in one of the 20 animals tested and confirmed by genetic sequencing. It is important to highlight that this is the first study comprising a molecular investigation of different zoonotic pathogens in six-banded armadillos, and the findings reported here bring new and important knowledge regarding zoonotic diseases in this species.

This study evaluated dynamics of antibodies in dogs treated for canine visceral leishmaniasis (CVL). Twenty-one dogs naturally infected by Leishmania spp. were grouped based on the treatment protocol: G1 (n=4) received allopurinol; G2 (n=10) allopurinol with miltefosine; and G3 (n=7) allopurinol, miltefosine and Leish-Tec® vaccine. The dogs were monitored monthly for a period of one year. To verify serum antibody titers, an indirect immunofluorescence reaction was performed. We found that dogs from G1 and G2 had lower clinical scores and antibody titers, when compared to the parameters evaluated in pre-treatment; however, clinical relapses were observed in three animals. In G3, clinical scores were lower than pre-treatment; however, they presented relatively stable antibody titers and no clinical relapse was observed. All animals submitted to the evaluated treatment protocols showed relative improvement in clinical signs. Furthermore, the immune response of animals must be considered, given the challenges of parasitic loads in infections. Therefore, it is necessary to complement the methods of clinical and therapeutic monitoring of dogs with CVL in order to establish the risk of transmissibility of the agent in infected and treated dogs.

The tucunaré (Cichla sp.) is an Amazonian fish that is heavily commercialized in the state of Amapá, and it can be infected by a variety of parasites, including coccidia of the genus Calyptospora, which are identified at the genus level by analyzing the structures that comprise its morphology. This study aimed to describe the morphology and histopathology of Calyptospora sp. parasitism in Cichla monoculus Spix, 1929 in the Municipality of Pracuúba, Amapá, Brazil. Nine specimens were acquired from the Lake Sacaizal by artisanal fishermen and transported in isothermal boxes to the Integrated Morpho-molecular and Technologies Laboratory (LIMT) of the Federal Rural University of the Amazon in Belém, Pará, where they were necropsied. Fragments of the liver were removed to visualize cysts using light microscopy and processed for scanning electron microscopy and histology analyses. The analysis revealed that 66.6% of the fish examined had clusters of oocysts in the hepatic region, resulting in the formation of melanomacrophagic centers. The oocysts were sphere-like, with a diameter of 21 µm. They contained four pyriform sporocysts, 8.7 µm long and 4.9 µm wide, with sporopods in the posterior region.

Bovine parasitic otitis poses challenges in diagnosis, treatment and involves various agents, such as bacteria, fungi, mites, and nematodes. This study focused on the nematodes and bacteria isolated from the auditory canals of dairy cattle. A total of twenty samples were collected from dairy cattle in two states of Brazil. The results showed that Metarhabditis freitasi and M. costai nematodes were identified in 75% of samples. Bacterial species from the ear, identified via mass spectrometry, revealed that different strains were present in 65% of the cattle. Mycoplasma spp. were identified in 45% of samples through molecular techniques. Gram-negative bacteria and Mycoplasma spp. were exclusively found in nematode-infected cattle. Furthermore, the bacteria exhibited resistance to multiple antimicrobial classes, and demonstrating multiresistance. Electron microscopy revealed biofilm aggregates on the cuticle of Metarhabditis spp., suggesting a potential role of these nematodes in bacterial migration and interaction with nervous tissue. Thirteen bacterial strains demonstrated biofilm formation ability, indicating their potential pathogenic role. This research highlights the persistent and complex nature of parasitic otitis, emphasizing the significant role of nematode-bacteria associations in its pathogenicity. The presence of resistant strains and biofilm formation underscores the challenges in managing the diagnosis and treatment of bovine parasitic otitis.

This paper describes a novel in vivo study of Cymbopogon citratus (lemon grass) to assess its anthelmintic activity. To this end, C57BL/6 mice were separated into three groups: G1: uninfected; G2: negative control infected with Heligmosomoides polygyrus bakeri and administered with 3% dimethyl sulfoxide (DMSO); and G3: infected with H. polygyrus bakeri and treated with C. citratus aqueous extract (50mg/kg). The extract and H. polygyrus bakeri were administered via gavage and the anatomo-histopathological evaluation of the animals took place after necropsy and organ removal. In addition, the number of eggs per gram of feces (epg) and of adult parasites in the small intestine of each animal, as well as blood cell counts, were assessed. The in vivo assay revealed a reduction in the epg (54%), number of adult nematodes (89%), number of eosinophils, and intestinal lesions in mice treated with C. citratus. These results suggest that the crude aqueous extract of C. citratus at the dose evaluated here has anthelmintic and possibly anti-inflammatory properties, given its effectiveness against gastrointestinal H. polygyrus bakeri nematodes and the recovery of damaged tissues. Therefore, this plant shows potential to control gastrointestinal nematodes.

Canine monocytic ehrlichiosis (CME) is an infectious disease that causes hematological changes in dogs. This study investigated the correlations between hematological and hemorheological parameters, serum proteins, and triglycerides in dogs with CME. Fifty-nine blood and/or bone marrow samples were collected from dogs with or without clinical signs of CME. Blood samples preserved with EDTA were subjected to rheological analysis to investigate blood viscosity. Fourteen dogs with Ehrlichia canis infection (CME group) and 20 without clinical signs and E. canis infection (CG) were selected by qPCR based on Ecaj_0503 gene. The blood viscosity of the infected dogs (CMEG) was lower than that of the control group (CG). The mean values and standard error of erythrocytes (CG: 6.71 ± 0.20; CMEG: 4.82 ± 0.23), platelets (CG: 235.6 ± 15.67; CMEG: 151.07 ± 16.51), and albumin (CG: 3.04 ± 0.15; CMEG: 2.65 ± 0.12) in the infected dogs were lower (p<0.005) than those in the control group. The decrease in erythrocytes influenced the decrease in blood viscosity. Total protein, albumin and triglycerides levels correlated with blood viscosity in infected dogs. Overall, this study shows that dogs with CME have decreased blood viscosity primarily due to anemia and interactions with negative acute-phase proteins.

A total of 384 animals (sheep, goat, cattle, and buffalo) were examined for the presence of hydatid cysts only in the lungs. The lung tissue samples associated with the hydatid cyst were collected immediately after slaughter, followed by fixation in 10% formalin. The fixed tissue was subjected to paraffin embedding technique. Tissue sections of 5 microns were cut by microtome and stained using Harri's Haematoxilin and Eosin method. Overall, 13.80% of ruminants were found positive for lung infections with hydatid cyst. Only the sex of ruminants showed significant (P < 0.05) association with the infection of hydatid cyst in lungs. All other variables, such as species of ruminants, age, and months showed non-significant (P > 0.05) association. Pulmonary sections taken from infected animals revealed laminated membranes encased in a region with significant (P < 0.05) cellular infiltration (53.4 ± 7.9 µm2), primarily composed of lymphocytes, plasma cells, macrophages, and occasionally neutrophils, and eosinophils. In addition, significant (P < 0.05) epithelial disruption in the bronchioles (0.94 ± 0.05 µm2) and alveolar septa were also noticed in sections. These histopathological findings lead to the conclusion that pathological changes occur in the tissues surrounding the cyst as well as in areas more distant from the cyst.

In Brazil, spotted fever (SF) is caused by two species of Rickettsia, both of which are transmitted by Amblyomma ticks: Rickettsia rickettsii, which results in severe and often fatal cases, and Rickettsia parkeri, which causes a mild illness. This study focused on R. parkeri in Amblyomma ovale ticks from the Maciço de Baturité region, Ceará, Northeast Brazil, an area endemic for SF with mild symptoms. We examined 60 domestic dogs with access to the forest for ticks and Rickettsia seroprevalence. A landscape analysis was conducted in all forest patches within 2-10 km from the main forest edge. In total, 125 A. ovale ticks were collected from 30 dogs (50%). DNA from 65 ticks was tested using genus-specific Rickettsia primers. Three (4.6%) tick specimens tested positive for R. parkeri while the Rickettsia seroprevalence among the dogs was 55% (33/60). A probable occurrence of Rickettsia transmission was observed in the fragmented Atlantic rainforest, which has 1,019 ha of preserved land and 50.6 km of perimeter border. The land's characteristics allow for semi-domiciled dogs to access forest fragments, where A. ovale ticks are commonly present. Infected ticks may parasitize the dogs, which then transport the ticks into homes, potentially transmitting SF-causing bacteria to humans.