RESUMO
The aim of this research was to study the contribution of Toxoplasma gondii to reproductive failure using nested PCR and histopathological examination of fetuses, stillborns and placentas. We examined 245 organs of fetuses and 28 placentas from 35 abortions and stillborns from naturally occurring miscarriages in sheep in the State of Pernambuco, Brazil. At necropsy, fragments of brain, cerebellum, medulla, lung, heart, spleen, liver and placenta were taken for nested PCR and histopathological tests. Pathological examination revealed macroscopic lesions, suggesting T. gondii infection in 5/35 (14.3%) of the placentas. The histopathological examination revealed no lesions characteristic of toxoplasmosis in the organs investigated. In the five placentas, lesions consistent with toxoplasmosis were observed as an inflammatory non-suppurative infiltrate, along with multiple necrosis and mineralization. Nested PCR showed three aborted fetuses and two stillborns (14.3%) to test positive for T. gondii, with DNA amplification in all organs and the placenta, especially the heart and the placenta, which are the tissues of choice. This study substantiates the theory that T. gondii is involved in miscarriages and stillbirths and in the placentas of naturally infected sheep in Brazil. Such findings have not previously been described in the national literature.
Assuntos
Complicações Parasitárias na Gravidez/veterinária , Doenças dos Ovinos/diagnóstico , Toxoplasma/isolamento & purificação , Toxoplasmose Animal/diagnóstico , Feto Abortado/parasitologia , Animais , Encéfalo/parasitologia , Brasil/epidemiologia , DNA de Protozoário/genética , Feminino , Coração/parasitologia , Fígado/parasitologia , Pulmão/parasitologia , Placenta/parasitologia , Reação em Cadeia da Polimerase/veterinária , Gravidez , Complicações Parasitárias na Gravidez/diagnóstico , Complicações Parasitárias na Gravidez/parasitologia , Reprodução , Ovinos , Doenças dos Ovinos/embriologia , Doenças dos Ovinos/parasitologia , Carneiro Doméstico , Baço/parasitologia , Natimorto/veterinária , Toxoplasma/genética , Toxoplasmose Animal/embriologia , Toxoplasmose Animal/parasitologiaRESUMO
Swayback disease (SD) which affects young sheep and a number of other animals is caused by the unavailability of metabolizable copper during the last half of pregnancy. In an effort to increase the present understanding of the development of SD and related human disorders we induced copper deficiency in pregnant ewes and studied its effects on pregnancy and the offspring. Nineteen pregnant ewes were rendered copper deficient by injection of ammonium tetrathiomolybdate (ATM), at 1mg/Kg during (I)the last 8-11 weeks, (II)the last 4-6 weeks and (III)the last 1-2 weeks of pregnancy. Treatment was continued until the lambs were weaned and sacrificed. Atomic absorption spectroscopy revealed that prolonged ATM treatment causes unpredictable changes in serum copper levels in the pregnant ewes, varying from large increases of 133 percent to large decreases of 65 percent. An unusually high number of treated ewes (29 percent) died during pregnancy. Neonates from ewes of the 1-2 week treatment group had normal serum copper levels, while 86 percent of the lambs from the 4-8 week group displayed subclinical serum copper levels (<0.5 ppm). Lambs from ewes in the 8-11 week group had serum copper levels ranging from moderate, 0.6 ppm to very high, 3.4 ppm. Nine of the 22 offspring showed signs of SD: none of these were from ewes receiving ATM treatment for the shortest period: 44 percent of the lambs from the intermediate group and 63 percent of those from the group receiving the longest ATM treatment were diseased. We conclude that while copper deficiency occuring in the last two weeks of pregnancy appears to have no effect, acute deficiency occuring at earlier stages, particularly the last 8-11 weeks, is likely to precipitate swayback disease in the offspring. Finally, it has been suggested that the early postnatal development stage of the human, corresponds to the final prenatal stage of the lamb, the present findings therefore suggest that the human foetus might be susceptible to copper deficiency even during the final weeks of pregnancy (AU)