Leonardo P. Mesquita

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.

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.

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.

Inclusões intracitoplasmáticas hialinas na medular da adrenal de bovinos

Cytoplasmic inclusion bodies in adrenal medullary chromaffin cells have been described in various species including humans. These inclusions are believed to be related to certain infectious, toxic and neurodegenerative diseases. No reports concerning such adrenal inclusions have been described in bovines. Adrenal glands from twenty bovines were evaluated in a retrospective study. Seven of these exhibited inclusions - three cases of rabies, two cases of chronic suppurative bronchopneumonia, one case of chronic suppurative peritonitis, and one case of gangrenous mastitis. The inclusions were present in higher numbers especially in cases of rabies and also in one case of chronic suppurative bronchopneumonia. The inclusions were intracytoplasmic, eosinophilic, rounded, single or multiple, of various sizes, strongly stained by PAS and were present in higher numbers in the external layer of the adrenal medulla. The inclusions were negative when subjected to immunohistochemistry for detection of viral antigens in the cases of rabies. Although inclusion bodies were present in adrenal glands devoid of other histological alterations, they were more abundant in cases in which the adrenal gland had other alterations. The correlation between certain diseases and the development of inclusion bodies is not known, which highlights the importance of further studies on these inclusions in adrenal glands of bovines.

Prevalência e aspectos anatomopatológicos das neoplasias primárias do coração, de tecidos da base do coração e metastáticas, em cães do Sul de Minas Gerais (1994-2009)

The purpose of this study was to determine the prevalence and anatomopathological findings of primary and metastatic heart tumors and from heart base tumors diagnosed in dogs from southern Minas Gerais, Brazil. The diagnosis was based on histological characteristics and immunophenotyping of the tumors cells. From 1994 to 2009, 2397 necropsies of dogs were performed. Cardiac neoplasms were diagnosed in 31 dogs (1.29%), where seven (22.58%) were primary and 24 (77.42%) were metastatic. Neoplasms of the heart diagnosed as primary were hemangiosarcoma (1/7) and myxoma (1/7), and, primary of heart base, the chemodectoma (3/7) and ectopic thyroid carcinoma (2/7). Frequency was higher in male dogs (5/7), of Boxer breed (3/7) with mean age of 9.7±1.88 years. In metastatic neoplasms, the frequency was higher in female dogs (15/24), of Rottweiler breed (7/24) with the mean age of 7.5±3.23 years. The T cell lymphoma (7/27) was the most frequent neoplasm, diagnosed as metastatic.