Aborto ovino associado com infecção por Sarcocystis sp / Ovine abortion associated with Sarcocystis sp. infection

Infecções por protozoários têm distribuição mundial e podem causar aborto, nascimentos prematuros e ou morte fetal em diversas espécies animais. Em julho de 2004, oito ovinos Corriedale apresentaram problemas reprodutivos caracterizados por aborto e natimortalidade no terço final da gestação. Dessas oito perdas, um natimorto macho foi enviado ao Setor de Patologia Veterinária para necropsia. Alterações macroscópicas não foram observadas durante a necropsia. Lesões histológicas foram observadas principalmente no cérebro e coração e se caracterizaram por encefalite não-supurativa multifocal acentuada associada à presença de protozoários no interior de células endoteliais e vasos sanguíneos e miocardite não-supurativa focal leve. Alguns desses organismos apresentaram formato de roseta. O teste de imunoistoquímica anti-Toxoplasma gondii foi negativo, mas houve reação cruzada com anticorpo anti-Neospora caninum. O exame de imunofluorescência direta para Leptospira sp. foi negativo. A bacteriologia aeróbica e micro-aeróbica não revelou crescimento significativo. Esses achados foram compatíveis com o diagnóstico de Sarcocystis sp.

Protozoal infection has worldwide distribution and may cause abortion, premature parturition or fetal death in almost all domestic animals. In July 2004, eight Corriedale sheep showed abortion and stillbirth in the third trimester of gestation. Of these reproductive losses, one stillborn male was submitted to the Laboratory of Veterinary Pathology for necropsy investigation. The direct immunofluorescence test for Leptospira sp. was negative. No significant bacteria was isolated from lung and liver by aerobic and microaerobic cultures. Macroscopic lesions were not found in any fetal tissue. The histological lesions were observed mainly in the brain and heart and consisted primarily of severe multifocal nonsupurative encephalitis and nonsuppurative myocarditis. Schizonts of a protozoan parasite consistent with Sarcocystis sp. were found in the endothelial cells and vascular endothelium in several organs. Many schizonts with merozoites arranged in a rosette-like pattern were observed in brain and kidney tissues. In sections stained with periodic acid-Schiff (PAS), the limiting membrane of some schizonts appeared to be weakly PAS-positive. Merozoites and nuclei were PAS-negative. Protozoa did not react immunohistochemically to the antibody anti-Toxoplasma gondii; however, cross-reactivity was observed with Neospora caninum antibody. These findings were consistent with the diagnosis of Sarcocystis sp.

Efectos de la infección aguda y crónica por Trypanosoma cruzi en la gestación de los ratones / Effects of acute and chronic Trypanosoma cruzi infection in pregnant mice

Pathogens may impair reproduction in association or not with congenital infections. We have investigated the effect of acute infection with Trypanosoma cruzi, the protozoan agent of Chagas disease, on reproduction of female mice. In the acute, parasitemic, phase of the infection, female mice were totally unable to reproduce. Most of them (80%) were infertiles and did not develop any gestation. In the few gravid infected mice, implantation numbers were as in uninfected control mice. However, their fetuses presented a weight meanly reduced by 40% as compared to those of uninfected females, and all of them died during the gestation or whithin 48 h after birth. Such massive mortality did not result from congenital infection, which did not occur. The infertility and the fetal mortality occuring early in gestation (resorptions) were significantly correlated with a high maternal parasitemia, whereas later fetal mortality was associated with the presence of intracellular parasites in the utero-placental unit. The decidua was particularly receptive to T. cruzi multiplication, since this tissue harboured 125 fold more amastigotes than the maternal heart or other placental tissues. In addition, placentas of dead fetuses presented histopathological lesions (inflammatory infiltrates, fibrine deposits and ischemic necrosis). Such harmfull effects of acute infection were not observed when female mice were in the chronic phase of the infection, since these reproduce normally. Their fetuses only suffered from moderate and reversible growth retardation. These results indicate that, following the maternal parasite burden, T. cruzi infection may induce very deleterious effects on gestation.

Influence of placental malaria infection on foetal outcome in the Gambia: twenty years after Ian Mcgregor.

Malaria infection in pregnancy has serious health consequences among mothers and offspring. The influence of placental malaria infection on foetal outcome was studied in a Gambian rural setting where few pregnant women take antimalarial chemoprophylaxis. During July-December 1997, three hundred thirteen mother-newborn pairs (singletons only) were consecutively recruited into a study of the effects of placental malaria infection on the outcome of pregnancy. Placental blood and tissue were collected at delivery. Babies were clinically assessed until discharge. The overall prevalence of placental malaria infection was 51.1% by placental histology and 37.1% by blood smear. The primigravid women were more susceptible to placental malaria than the multigravidae (65.3% vs 44.7%, p=0.01). Placental malaria was significantly associated with pre-term deliveryand intrauterine growth retardation (p<0.01), and there was a four-fold risk of delivering low-birth-weight babies if mothers had parasitized placentae [OR=4.42, 95% confidence interval (CI) 2.10-9.27]. A reduction of mean birth-weight of babies by 320 g was associated with placental malaria infection (p<0.001). Similarly, a two-fold risk of stillbirth delivery (OR=2.22, 95% CI 1.04-4.72) was observed among the infected mothers. The findings showed that there was still an overall poor foetal outcome associated with placental malaria infection. The findings of this study confirm the findings of an earlier study by McGregor in the Gambia that the low birth-weight rate is significantly higher if the placenta is parasitized. In addition, this study observed that the high stillbirth and prematurity rates were associated with placental malaria infection. The findings of the present study suggest undertaking of effective malaria-control strategies during pregnancy, such as use of insecticide-impregnated bednets, intermittent and early treatment for malaria, and antimalarial chemoprophylaxis, in the Gambia.

Toxoplasmosis y aborto en evolución / Toxoplasmosis and abortion in evolution

Para conocer la prevalencia de toxoplasmosis en población abierta de Comitán Chiapas, se realizó estudio serológico por inmunofluorescncia indirecta en voluntarios sanos. Además se identifico la presencia de anticuerpos anti Toxoplasma gondii en 50 mujeres con aborto en evolución. Los resultados mostraron que alrededor de 5 por ciento de la población general tiene títulos positivos de anticuerpos anti Toxoplasma gondii, y el 18 por ciento en el caso de las mujeres con aborto en volución. Se concluyó que la seropositividad para esta parasitosis estadísticamente es signficativa en los casos de aborto que entre la población general (P<0.006) y también, es significativamente mayor a las mujeres con aborto, que con respecto a la mujeres de la población general de Comitán Chiapas (P<0.01)

Serological diagnosis of Toxoplasma gondii infection in women associated with gyneco-obstetric problems.

The latex agglutination test (Toxoreagent) was used to detect the sero-prevalence of Toxoplasma gondii in 302 Bangladeshi women who were under treatment for various gyneco-obstetric problems at the Mymensingh Medical College during January to June 1991. The over-all sero-prevalence rate was 15.89%, of which 6.25% reacted at 1:32, 33.33% at 1:64, 16.67% at 1:128, 22.92% at 1:256, 6.25% at 1:512 and 14.58% at 1:1024. The positivity rate of 18.60% recorded in women between 31 and 40 years was insignificantly (p > 0.05) higher than that of 15.44% in women between 17 and 30 years of age. Over-all 26.49% of infections resulted in abortion, 6.62 in stillbirths and 30.79% in dystocia, of which 20.0%, 30.0% and 7.53% women had positive titers to T. gondii, respectively, whereas 17.43% women with normal live births had also positive titers to T. gondii. The over-all prevalence rate of abortion in association with T. gondii infection was 5.30% which was higher than the rates of stillbirths (1.99%) and perinatal death (0.66%). It is concluded that toxoplasmosis can cause abortion, stillbirths and perinatal death in Bangladeshi women.

Epidemiology of swine toxoplasmosis in Taiwan.

From July 1987 to June 1988, serum samples from 3,880 pigs from eight geographic locations in Taiwan were examined for Toxoplasma gondii antibodies using the latex agglutination test (LA test) and IgM-enzyme-linked immunosorbent assay (IgM-ELISA). A total of 1,073 samples (27.65%) were positive by the LA test. The percentage of positive reactions varied by location as follows: Taoyuan 44.44% (128/288), Taichung 27.60% (183/663), Tainan 22.28% (119/534), Kaohsiung 19.60% (98/500), Pingtung 17.92% (86/480), Hualien 33.95% (163/480), Ilan 31.66% (152/480), Taitung 31.64% (144/455). In the IgM-ELISA 1,828 of 3,880 samples (47.11%) were positive and the distribution of positive reactions were: Taoyuan 59.02% (170/288), Taichung 53.69% (356/663), Tainan 52.24% (279/534), Kaohsiung 54.60% (273/500), Pingtung 18.95% (91/480), Ilan 47.50% (228/480), Hualien 42.70% (205/480), Taitung 49.67% (226/455). On one farm, 20 of 120 sows experienced abortion and stillbirths due to Toxoplasma gondii. Lesions and T. gondii were found in lungs, liver, kidneys, heart, and placenta of one of the aborted fetuses.