Mary Suzan Varaschin

Intoxicação experimental por Baccharis coridifolia (Compositae) em bovinos

Thirteen calves were fed single doses varying from 0.5 to 5g/kg of either freshly harvested or dried Baccharis coridifolia. One calf was fed 4 daily doses of 0,5g/kg of the dried plant. Two calves did not receive the plant and served as controls. The plant material was harvested each month from July 1991 to May 1992 and then in March 1993, and was analysed for its content in macrocyclic trichothecenes. When in flower the female and male plant specimens were both analysed and fed separately to calves. The levels of macrocyclic trichothecenes and their glucosides were much higher in the flowering female plants compared with the levels observed in those plants not in flower and in the flowering male plants. Ten calves either died or were euthanatized due to the toxicosis. Two calves fed the female flowering plant got sick and died, while 3 calves fed the flowering male plant did not develop the toxicosis. Clinical signs in the poisoned calves were anorexia, dehydration, ruminal atony, abdominal distension and pain, liquid diarrhea, dry muzzle, imbalance in the hindlimbs and sternal recumbency. Main pathological findings included necrosis of the gastrointestinal tube, particularly in the forestomachs and in the lymphoid tissues except for the thymus. The latter suggests an effect upon the B cells of the lymphoid tissue. The distribution of the lesions in the digestive and lymphoid systems was sistematically determined. It is concluded that the macrocyclic trichothecenes present in the plant account for the lesions observed in the toxicosis and that the female flowering plant is substantially more toxic than the flowering male plants or plants not in flower. This difference in toxicity is due to the difference in macrocyclic trichothecenes contents.

Congenital Neosporosis in Goats from the State of Minas Gerais, Brazil

Congenital Neospora caninum infection was diagnosed in two Saanen goat kids from two distinct herds with a history of abortion and weak newborn goat kids in the Southern region of the State of Minas Gerais, Brazil. The first kid was weak at birth, had difficulty to rise and was unable to nurse. Gross lesions of porencephaly and hydrocephalus ex vacuo were seen. Multifocal necrosis, gliosis and non-supurative encephalitis were observed in the brain. Several parasitic cysts with a thick wall that reacted strongly only with polyclonal antiserum to Neospora caninum were seen in the cerebral cortex, brain stem and cerebellum. The second kid was born from a Neospora caninum seropositive mother that aborted in the last pregnancy. It was born without clinical signs. The diagnosis of neosporosis was based on antibody titer of 1:800 to N. caninum by indirect fluorescence antibody test obtained from blood collected before the goat kid ingested the colostrum and Neospora caninum DNA was detected by polymerase chain reaction and sequenced from placenta. This is the first report of neosporosis in goats in the southeast region of Brazil.

Antibody kinetics in goats and conceptuses naturally infected with Neospora caninum

Neospora caninum is a protozoan which can cause abortions in caprines. However, information regarding the humoral immune response and the occurrence of reproductive disorders is scarce. This is the first study in which the kinetics of antibodies is studied in pregnant goats naturally infected by N. caninum, as well as their respective conceptuses. The subclasses of IgG (IgG1 and IgG2) were also evaluated in pregnant goats. Reproductive problems related to neosporosis (abortion and stillbirth) occurred in 15.38% of the goats. There was a statistically significant association between the increased titres of maternal IgG in the second half of the gestational period with the occurrence of endogenous transplacental transmission. The rate of congenital transmission was 77%. During the gestational period of the seropositive goats, there was mainly a predominance of the subclass IgG2, although mixed patterns of IgG2-IgG1 and the IgG1 pattern were also observed. These results indicate that N. caninum is responsible for the occurrence of important alterations in the humoral immune response of naturally infected goats, and is also a potential causative agent for reproductive disorders in goats. The high proportion of infected conceptuses reinforces the suggestion that congenital infection is one of the main routes of parasite transmission in goats.

Neospora caninum in bovine fetuses of Minas Gerais, Brazil: genetic characteristics of rDNA.

Neosporosis is an important cause of abortion in cattle and information on their genetics and host parasite relationships are desirable. Neospora caninum samples obtained from 24 bovine fetuses from Minas Gerais, were genetically analyzed in part of the rDNA region, coding for rRNAs. Previously, brain, heart, liver, skeletal muscle, lung, kidney, spleen, thymus, lymph nodes, ovary or testis, uterus and skin of the ear were analyzed by conventional histopathology and immunohistochemistry. Of these, eight had lesions compatible in the brain and heart and two also in skeletal muscle and liver. Three brains showed antigen identification in immunohistochemistry. Brain and heart tissues were subjected to DNA extraction for PCR, whose product of 588 bp of ITS-1 region was sequenced in three samples. We obtained 96% similarity with dozens of sequences N. caninum deposited in GenBank. The phylogenetic tree showed great conservation among isolates of N. caninum in this study and those deposited in GenBank, while well-defined and specific branches were generated against other Apicomplexa. PCR for this region is useful as a diagnosis, with good analytical specificity, but the ITS-1 region is not suitable for genetic differentiation intra species because the sequences obtained were identical to the others analyzed.

Risk factors associated with seroprevalence of Neospora caninum in dogs from urban and rural areas of milk and coffee production in Minas Gerais state, Brazil

This study was conducted to determine the seroprevalence of anti-Neospora caninum antibodies and to investigate the risk factors related to seroprevalence in dogs from urban and rural areas with distinct economic activities (milk and coffee production) in Minas Gerais state, Brazil. For this purpose, blood samples from 703 dogs were collected and questionnaires addressing epidemiological aspects were completed by dog-owners. The sera were analysed for anti-N. caninum antibodies by indirect fluorescent antibody tests (IFAT ≥ 1:50). Association between epidemiological aspects and seropositivity in dogs was evaluated with multivariate logistic regression models. A total of 80 (11·4%) dogs tested positive for N. caninum. In the multivariate logistic regression models, dogs aged >4 years, dogs used as guard dogs, dogs that spontaneously hunt, and history of bovine abortion were found to be greater risk factors for canine N. caninum infection. When we considered only dogs from rural areas, an association with seroprevalence was seen for milk farms, dogs not fed with commercial food, dogs that hunt, and dogs used as guard dogs.

Fatores associados a soroprevalência de Neospora caninum e Toxoplasma gondii em rebanhos caprinos na região sul de Minas Gerais

This study determines the seroprevalences of Neospora caninum and Toxoplasma gondii in caprine herds in southern Minas Gerais state and investigates their association with the reproductive performance of the herds analyzed since no data concerning neosporosis in goats in this state are available. Serum samples from 401 goats from 11 farms were subjected to indirect immunofluorescence reaction for the detection of N. caninum and T. gondii. The mean prevalence rates of animals that tested positive were 10.7% and 21.4%, respectively. Significant differences between different age groups were observed. The highest frequencies of positive cases for both parasites were observed in goats over three years of age; in this group, the probability of seropositivity for N. caninum and T. gondii was 2.6 and 4.8 times higher, respectively, when compared to animals up to one year of age. No positive correlation was found between the mean prevalence rate of N. caninum (p-0,553) and T. gondii (p=0.098) and the occurrence of reproductive problems in the herds using T-test. However, farms with a history of reproductive problems exhibited an average of 18.64% animals reactive to N. caninum, compared to 13.97% from farms where those problems were not reported. When reproductive problems were separated in category, the relationship between occurrence of abortion and seroprevalence of N. caninum and T. gondii was significant (p 0.05) between the mean prevalence rate of T. gondii of herds to which cats had access as compared to herds that had no contact with cats using a T-test. However, the mean prevalence rate in farms where cats had access to the herd was 31.01% as compared to 17.34% in farms where there were no cats. Access of dogs was observed in 100% of the farms. The results obtained in this study demonstrate that N. caninum and T. gondii infect goats in southern Minas Gerais and that these parasites can be associated with the occurrence of abortion in this animal species.

Histological and immunohistochemical characterization of the inflammatory and glial cells in the central nervous system of goat fetuses and adult male goats naturally infected with Neospora caninum

BackgroundNeospora caninum is an apicomplexan protozoan that is considered one of the main agents responsible for abortion in ruminants. The lesions found in the central nervous system (CNS) of aborted fetuses show multifocal necrosis, gliosis, and perivascular cuffs of mononuclear cells, but the inflammatory and glial cells have not been immunophenotypically characterized. The lesions in the CNS of infected adult animals have rarely been described. Therefore, in this study, we characterized the lesions, the immunophenotypes of the inflammatory and glial cells and the expression of MHC-II and PCNA in the CNS of goats infected with N. caninum. The CNS of eight aborted fetuses and six adult male goats naturally infected with N. caninum were analyzed with lectin histochemistry (RCA1) and immunohistochemistry (with anti-CD3, −CD79α, −GFAP, −MHC-II, and -PCNA antibodies). All animals were the offspring of dams naturally infected with N. caninum.ResultsThe microscopic lesions in the CNS of the aborted fetuses consisted of perivascular cuffs composed mainly of macrophages (RCA1+), rare T lymphocytes (CD3+), and rare B lymphocytes (CD79α+). Multifocal necrosis surrounded by astrocytes (GFAP+), gliosis composed predominantly of monocytic-lineage cells (macrophages and microglia, RCA1+), and the cysts of N. caninum, related (or not) to the lesions were present. Similar lesions were found in four of the six male goats, and multinucleate giant cells related to focal gliosis were also found in three adult goats. Anti-GFAP immunostaining showed astrocytes characterizing areas of glial scarring. Cysts of N. caninum were found in three adult male goats. The presence of N. caninum was evaluated with histopathology, immunohistochemistry, and PCR. Immunohistochemistry demonstrated anti-PCNA labeling of macrophages and microglia in the perivascular cuffs and the expression of MHC-II by microglia and endothelial cells in the CNS of the aborted fetuses and adult male goats.ConclusionsMacrophages and microglia were the predominant inflammatory cells in the CNS of aborted fetuses and healthy adult male goats infected with N. caninum. Activated astrocytes were mainly associated with inflamed areas, suggesting that astrocytes were involved in the resolution of the lesions.

Abortos por Neosporacaninum em bovinos do sul de Minas Gerais

The present study evaluates the participation of Neospora caninum in bovine abortions from farms in the southern region of Minas Gerais state, Brazil, through histopathological, immunohistochemical (IHQ) analysis and DNA detection by polymerase chain reaction (PCR). The material used in this study was obtained through retrospective study of bovine abortion cases received by the Setor de Patologia Veterinaria da Universidade Federal de Lavras and by necropsies performed in fetuses from 2011 to 2013. From 60 fetuses studied, 30 (50%) had microscopic lesions; 19 (63%) of them had histologic lesions compatible with N. caninum abortion, characterized by multifocal non-suppurative encephalitis, necrosis and gliosis in the central nervous system and multifocal nonsuppurative myocarditis and myositis. From the 19 fetuses with protozoa lesions in 14 the final diagnosis was performed; five were confirmated only by IHQ staining and five were positive only by PCR. Four fetuses were positive in IHC and in PCR. In five fetuses from the retrospective study lesions compatible with N. caninum were seen, but the presence of the protozoan was not confirmed by IHQ labeling. The findings demonstrate that N. caninum is an important agent associated with abortion in cattle from Minas Gerais. Therefore, beyond the microscopic lesions association between IHC and PCR was essential to confirm the diagnosis.

Aspectos clínico-patológicos e imuno-histoquímicos de equídeos infectados pelo vírus da raiva

Thirteen horses and one mule from four regions of Brazil with clinical and histological diagnosis of rabies were analyzed. The clinical course lasted four days, with motor incoordination, paresis and paralysis of the legs, and decubitus. The main histopathological findings were lymphoplasmacytic meningoencephalitis and non-suppurative meningomyelitis associated with characteristic Negri bodies in 64.28% (9/14) cases, mainly in the cervical spinal cord and in Purkinje neurons of the cerebellum. In 55.55% (5/9), the animals examined were positive by for the fluorescent antibody test for rabies. All animals were positive in immunohistochemistry for rabies, whose immunolabeling were more evident in the temporal cortex, occipital cortex and cervical spinal cord. Immunohistochemistry procedure was essential to confirm all cases of rabies in the equids.

Surto de compactação primária de abomaso em bovinos leiteiros associado ao consumo de silagem de girassol

An outbreak of primary abomasal impaction associated with consumption of sunflower silage occurred in a dairy cattle herd from the state of Minas Gerais. Six of 21 dry cows in late pregnancy fed with sunflower silage died. Cattle that became ill presented abdominal distension and scant and dried feces. In the animals that died, severe dehydration, pale mucous membranes, dark, sticky and stinking feces were seen. Three cows were necropsied and the main pathological findings consisted of severe abomasal distension associated with a large quantity of dried alimentary content covered by bloody clots. Ulcers were found in abomasum, with perforation in one cow. Feeding cattle with high nutritional needs, with sunflower silage of undesirable characteristics as unique source of roughage was the main cause for the abomasal impaction.