Neospora caninum in aborted twin calves

Neospora caninum was detected in the brains of twin aborted calves by means of a specific immunohistochemical test on formalin-fixed, wax-embedded tissues. Microscopic lesions associated with this infection included multifocal necrosis and gliosis in the brain accompanied by a mononuclear, perivascular inflammatory reaction and meningitis; and severe, diffuse epicarditis and subepicardial myocarditis characterised by infiltration of macrophages, lymphocytes and plasma cells. This report documents the first diagnosis of this parasite as a cause of bovine abortion in South Africa.

Toxoplasmosis in pregnancy

Primary infection with Toxoplasma gondii in pregnant women occurs all over the world with frequencies between 0.1-1%. In approximately 40% of the cases, the unborn child is infected. The risk of fetal infection increases during pregnancy, while at the same time the risk of severe disease decreases. As a result, infants with congenital toxoplasmosis are mostly asymptomatic at birth, but long-term studies indicate that up to 85% of them will develop sequelae including chorioretinitis (leading to severe impairment of vision), hearing loss or mental retardation. Early recognition of maternal infection and treatment with spiramycin or pyrimethamine-sulphadiazine will reduce the parasitic colonization of the placenta by more than 60% and prevent infection in the fetus. If fetal infection has already occurred, maternal treatment modifies the fetal disease. Therapy during the first year of life improves the prognosis. It is possible today to identify infected fetuses by prenatal diagnosis based on detection of the parasite in cord blood, amniotic fluid and placental tissue. Specific antibodies and non-specific signs of infection in fetal blood give additional information. Advances in laboratory techniques have made it feasible to consider serological surveillance of pregnant women. The present recommendation is that each country should provide data on the incidence of toxoplasma infection in pregnancy and thereby decide whether it represents a problem and what measures should be adopted. This paper summarizes the present knowledge of the parasite and its implication for the mother and unborn child. The effect and problems of primary and secondary prevention in pregnancy are discussed as well as the efficacy of treatment. The need for future research including long-term follow-up studies are emphasized.

In utero treatment of toxoplasmic fetopathy with the combination pyrimethamine-sulfadiazine

The mothers of 52 fetuses with toxoplasma fetopathy diagnosed in utero were treated with a combination pyrimethamine-sulfa drug and spiramycine. Their infants were compared to a group of 51 infants whose mothers had received spiramycine alone. Postnatal treatment was identical in both groups. Parasitological investigation of the placenta was positive in 42 and 76.6%; the newborns had a specific IgM of 17.4 and 69% in groups 1 and 2, respectively. These differences were significant. The mean specific IgG titer was significantly reduced at birth and at 4-6 months of age in group 1. According to the results obtained in the present material the pyrimethamine-sufa drug combination, given to the mothers of fetuses infected with toxoplasma, has a significant effect on the parasitological and serological signs of evolutive fetopathy. It did not significantly alter the clinical pattern, probably because the onset of treatment was too long after maternal infection.

Neosporosis in the aborted fetus and newborn calf

Protozoal encephalitic lesions were found in four aborted fetuses and one dead newborn calf. The organism was identified as Neospora caninum by immunoperoxidase. The brain lesions were of two forms. One was observed in three fetuses of 5 months gestation and was characterized by multifocal necrosis. The other was found in a 7-month fetus and in a newborn calf, and showed severe infiltration with macrophages and plasma cells containing IgG. This association, between the age of fetus and inflammation, may reflect development of the immune system in bovine fetuses.

[Research on the relation between intrauterine infection and intrauterine growth retardation]

To investigate the relationship between intrauterine infection and IUGR, the following studies have been carried out: (1) measurement of specific antibodies of Toxoplasma (Toxo) and Cytomegalovirus (CMV) in the umbilical serum samples from 30 cases of IUGR with 26 normal newborn infants as controls; (2) follow-up exam on 14 positive cases in 17-25 months. The results showed that in 30 IUGR cases 14 were found to have Toxo and CMV infection, with an incidence significantly higher than that in the control group. One third of the infected patients were found to have retarded growth afterbirth and 63.63% of them appeared to have an increase in BAEP. This suggested that regular follow-up is indicated in these cases.

Evidence of prenatal infection in the bottlenose dolphin (Tursiops truncatus) with the lungworm Halocercus lagenorhynchi (Nematoda: Pseudaliidae)

Adult lung nematodes identified as Halocercus lagenorhynchi were collected from the lungs of four Tursiops truncatus calves. The calves ranged in age from newborn to 3-wk-old and were found on both the Atlantic and Gulf coasts of Florida (USA). This finding suggests the possibility of a more cosmopolitan distribution of prenatal infection with lung nematodes in cetaceans than previously suspected.

Detection of congenital toxoplasmosis by chorionic villus sampling and early amniocentesis

We describe a strategy used in this case to detect congenital toxoplasmosis early in pregnancy. Combination of chorionic villus sampling and early amniocentesis with an in vitro cell culture technique makes prenatal diagnosis of congenital toxoplasmosis possible from the end of the first trimester of pregnancy.

Neospora caninum (Apicomplexa) in an aborted equine fetus

Tachyzoites of Neospora caninum were found in sections of lung of an equine fetus aborted 2 mo before term. Individual tachyzoites were approximately 3-5 x 2-3 microns, divided by endodyogeny, and stained positively with anti-N. caninum serum but not with anti-Toxoplasma gondii serum. Toxoplasma gondii antibody was not found in the mare's serum. This is the first report of N. caninum in a horse and indicates that N. caninum can be transmitted transplacentally in equids.

Diagnosis of transplacentally induced toxoplasmosis in pigs

Seventeen sows were fed 1,000 Toxoplasma gondii oocysts of isolates GT-1 or PT-1 at 32 to 92 days of gestation, and the products of conception were examined for T gondii antibodies and parasites. Twelve of these sows were euthanatized near term between 21 and 62 days after being fed T gondii; fetal body fluids or fetal sera were examined for agglutinating T gondii antibodies, and tissues were bioassayed in mice for T gondii parasites. Six sows produced pigs that had been transplacentally infected with T gondii; one of them aborted a T gondii-infected fetus 17 days after ingesting oocytes. Agglutinating antibodies were detected in fetuses infected in utero, but transplacental transfer of T gondii antibodies was not observed in noninfected fetuses. Transcolostrally acquired T gondii antibodies disappeared by 3 months of age. Diagnosis of transplacental toxoplasmosis was confirmed on the basis of detection of T gondii organisms in fetal tissues by use of histologic examination and bioassay in mice. In conclusion, finding of T gondii antibodies in body fluids could serve as a rapid screening test for transplacental T gondii infection in pigs.

[Practical problems posed by toxoplasmosis during pregnancy]

The occurrence of toxoplasmosis during pregnancy raises numerous problems. Determination of the time of the maternal infection is the first problem since we know that the frequency and gravity of fetal involvement vary according to the term of the pregnancy. Then, with information obtained from prenatal diagnostic tests (sonogram, amniocentesis, fetal blood sampling), it is important to recognize infected fetuses and advocate a management which goes beyond therapeutic abortion. Finally, the final problem is the follow-up of these children; in fact, after all these diagnostic and therapeutic measures, it is unfortunate that many children become lost to follow-up after the first year.

Neosporosis-like abortions in a herd of dairy cattle

Twenty-nine cows from a 240-cow drylot Holstein dairy in north-central New Mexico aborted over a period of approximately 5 months. Nine aborted fetuses were necropsied, and all but 1 of the fetuses were between 5 and 7 months of gestation. Microscopic examination of fetal tissues revealed focal necrotizing encephalitis and nonsuppurative myocarditis in 7 of the 9 fetuses. Additional lesions observed in some fetuses were focal hepatic necrosis, nonsuppurative myositis, focal necrotizing placentitis, focal nonsuppurative pneumonia, and focal nonsuppurative nephritis. A few groups of Neospora caninum-like protozoan organisms were observed adjacent to necrotic foci in the brain of 2 fetuses and in the kidney of a third fetus. No other cause of abortion was detected.

Experimental cryptosporidiosis in fetal lambs

Fetal lambs were infected in utero with purified sporulated oocysts of Cryptosporidium parvum in order to study pathogenesis and host cellular response to the enteropathogen. Ileal loops (IL) of fetuses, 124-130 days of gestation, were inoculated with 1-4 x 10(6) oocysts usually via cannulae in the abdominal wall of the ewe. Oocysts, both free and phagocytosed, were observed in the IL content as early as day 1 post-inoculation (PI). The percentage of oocysts phagocytosed by the host's polymorphonuclear neutrophils (PMN's) and mononuclear cells remained high up to day 13, the last day of examination. Numerous parasites were observed at days 6, 7, and 12 PI in the microvilli of the ileum with hypercellularity of the lamina propria, which consisted of a mixed infiltration of PMN's, mononuclear cells, including lymphoid cells, and a few eosinophils. Cytolysis and extrusion of epithelial cells, often heavily parasitized by various stages of the parasite, as well as inflammatory cells, were prominent in luminal contents. Germinal centers were prominent in mesenteric lymph nodes draining the infected loops by day 12 PI. Depletion of lymphoid cells was already present in Peyer's patches by day 4 PI.

Parasites and pregnancy: the problems of malaria and toxoplasmosis

Infections caused by parasites are common and not limited to the developing world. The spectrum of interactions between pregnancy and parasite infection ranges from minor discomfort to fetal death and are well illustrated by the problems of toxoplasmosis and malaria.

Subcutaneous and intestinal vaccination with tachyzoites of Toxoplasma gondii and acquisition of immunity to peroral and congenital toxoplasma challenge

Mice were immunized s.c. or intraintestinally with two injections of a temperature-sensitive mutant of Toxoplasma gondii (ts4). Nonpersistence of the vaccine strain was documented by subinoculation of tissues of a subgroup of mice 3 mo or more after the second immunization. Mice were immune to other-wise lethal parenteral challenges with tachyzoites of the M7741 strain or to peroral challenge with bradyzoites of the Me49 strain of T. gondii. Although two s.c. or intraintestinal immunizations did not completely protect against development of T. gondii in the brains of mice, fewer cysts developed in the s.c. immunized mice than in control mice (2 +/- 3 cysts/0.01 ml in immunized mice compared with 75 +/- 48 cysts/0.01 ml in controls (p less than 0.002)). Reduction in cyst number after intraintestinal immunization was more variable, but also statistically significant (p less than 0.02). Female mice were first immunized, then mated, and then challenged perorally. Neonates of the s.c. immunized mice were not protected. Neonates of intraintestinally immunized mice were protected in part (36% of 115) against congenital infection compared with controls (7% of 107).

Congenital spirochetosis in calves: association with epizootic bovine abortion

Congenital spirochetosis was encountered as a newly recognized infection of cattle. The spirochete was seen in blood of fetuses with lesions of epizootic bovine abortion. A spirochete with morphologic features similar to those found in the fetuses was detected in Ornithodoros coriaceus ticks. Ticks collected from rangelands were allowed to feed on cows that then produced epizootic bovine abortion-affected fetuses, and the fetuses had spirochetosis. Inapparent spirochetosis also was found in fetuses in clinically normal cattle sent to slaughter. Only a few lesions were seen in abattoir-collected fetuses. Fetal spirochetosis was common in the bovine population studied, and it appeared that infection may be limited only by the availability of the tick vector.

Sarcocystosis in an aborted bovine fetus

Sarcocystosis was diagnosed in an aborted bovine fetus. Immature and mature schizonts of Sarcocystis were disseminated in the vascular endothelium of all organs, but especially the brain. Microscopic granulomas, focal gliosis, and petechial hemorrhages in the neuropil were scattered in the brain. Multifocal collections of mononuclear cells were observed in the kidney, liver and heart. Organisms in sections of frozen tissues were demonstrated by immunofluorescent techniques to be Sarcocystis.

Transplacental transmission of Protostrongylus sp. in California bighorn sheep (Ovis canadensis californiana) in Oregon

Transplacental transmission of Protostrongylus sp. was documented for the first time in California bighorn sheep (Ovis canadensis californiana) by recovery of third stage larvae from two fetuses.

Prenatal infection of the Rocky Mountain bighorn sheep (Ovis c. canadensis) of Alberta with the lungworm Protostrongylus spp

First- and third-stage (infective) larvae of Protostrongylus spp. were recovered from the livers of four fetuses of the Rocky Mountain bighorn sheep of Alberta. This record suggests a more cosmopolitan distribution of prenatal infection with lungworms in bighorn sheep than suspected previously.

[Toxoplasmosis and interruption of pregnancy. Results of 21 parasitologic examinations]

Mouse inoculations were carried out after 21 pregnancies had been terminated for acquired toxoplasmosis. Only one positive result was obtained.