A Neospora-like protozoon found in an aborted bovine placenta

doi:10.1016/0304-4017(89)90174-X

Veterinary Parasitology

Volume 34, Issues 1–2, November 1989, Pages 145-148

https://doi.org/10.1016/0304-4017(89)90174-X Get rights and content

Abstract

Portions of the placenta and kidneys from a 5-month-old bovine fetus were examined histologically. The placental cotyledonary villi were necrotic and protozoa were found in lesions. The organisms were in trophoblasts, periodic acid Schiff-negative and did not react in an immunoperoxidase test using anti-Toxoplasma gondii serum. Individual zoites were ∼ 5×2 μm and the biggest collection was 45 × 35 μm. The organism in the present case was structurally distinct from Sarcocystis spp. and Toxoplasma gondii, but resembled Neospora caninum.

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Cited by (49)

Diagnosis and Control of Bovine Neosporosis
2016, Veterinary Clinics of North America - Food Animal Practice
Citation Excerpt :
The prevalence of bovine neosporosis was probably much lower under those circumstances. In recent decades, and accelerating since the time that bovine neosporosis abortion was first described in 1988,56,57 cattle enterprises are increasingly mechanized. Tractors and milking machines have enabled farmers to keep more and more cows in smaller and smaller spaces.
A review of Neospora caninum in water buffalo (Bubalus bubalis)
2015, Veterinary Parasitology
Citation Excerpt :
In situations where cattle and buffalo inhabit the same environment, water buffalo appear to show a higher sero-prevalence of infection, despite what should be, at face value, similar potential for exposure (Moore et al., 2014). N. caninum infections have been reported for thirty years, initially from dogs, then from calves with congenital neurological disease (O'Toole and Jeffrey, 1987; Parish et al., 1987), and subsequently from aborting cattle (Bjerkås et al., 1984; Shivaprasad et al., 1989; Thilsted and Dubey, 1989). The first report of antibodies in water buffalo goes back to 1995 and reported a sero-prevalence of 1.5% from 200 water buffalo blood samples collected at an abattoir in Vietnam (Huong et al., 1998).
A number of countries in the world have reported infections with Neospora caninum in water buffalo (Bubalus bubalis), from Africa to Asia, Europe and South America and recently Australia. In general, clinical manifestations (such as abortion) seem rare, which has raised the prospect that buffalo may be inherently resistant to clinical effects of N. caninum infection. Worldwide, the seroprevalence of N. caninum infection (as a measure of exposure determined by the detection of antibody) in buffalo is high, at approximately 48%. This reported seroprevalence is three or four times higher than that reported from the world's cattle populations, which have collective seroprevalence rates of 16.1% for dairy cattle and 11.5% for beef cattle. However, there is a lack of standardisation in seroprevalence studies and some studies may well under-estimate the true level of infection. Epidemiologic evidence supports post-natal transmission, and in utero transmission has also been demonstrated. The causes for water buffalo to have markedly higher seroprevalence but apparently lower neosporosis abortion rates than cattle warrant further investigation.
Characterization of the Inflammatory Response in the Uteri of Cows Infected Naturally by Neospora caninum
2013, Journal of Comparative Pathology
Citation Excerpt :
However, although no uterine inflammatory process was detected, the possibility that that the greater number of lymphocytes found in the placentas of seropositive cows in the present study is associated with the presence of N. caninum cannot be excluded. The presence of necrotic foci in the placentomes of two cows from the seropositive group coincide with the findings described by Shivaprasad et al. (1989), who found necrosis in fetal villi and structures consistent with tachyzoites inside trophoblasts, but did not observe inflammatory infiltration. Likewise, in studies where N. caninum tachyzoites were inoculated experimentally into cows early in gestation (70 days) and in mid-gestation (140 days), necrotic foci were present in the placentomes at 14 days post inoculation (Maley et al., 2003, 2006; Macaldowie et al., 2004).
Bovine neosporosis manifests during gestation, when the fetus may be vulnerable to pathogens. Experimental studies of Neospora caninum-infected cattle have been performed, but little is known about the in-utero inflammatory response. The aim of this study was to characterize the inflammatory response in the uteri of pregnant and non-pregnant cows infected naturally with N. caninum. Four groups of seven animals were studied. Two groups consisted of N. caninum-seropositive pregnant and non-pregnant cows and the other two groups contained N. caninum-seronegative pregnant and non-pregnant cows. Uterine and placental samples were subjected to immunohistochemistry using antibodies specific for N. caninum, CD4, CD8, CD14 and CD21. The non-pregnant seropositive and seronegative groups did not show a difference (P >0.05) in the types of cells present. There were more lymphocytes in the uteri of the seropositive pregnant animals (P <0.05) than in the seronegative pregnant animals, but this was not considered to be consistent with an inflammatory process. N. caninum cysts were detected in eight seropositive cows; five were non-pregnant and three were pregnant. CD4⁺ T cells were distributed in the endometrium and myometrium of the non-pregnant cows and were sparse in the placentomes of pregnant cows. CD8⁺ T cells were distributed in a similar manner, but were present in smaller number. There were no cells expressing CD14 or CD21. The results of the study suggest that there is no consistent uterine inflammatory response against N. caninum in naturally infected animals.
Increased incidence of DNA amplification in follicular than in uterine and blood samples indicates possible tropism of Neospora caninum to the ovarian follicle
2012, Veterinary Parasitology
Citation Excerpt :
The high incidence of positive results in follicle samples and the low agreement between blood leukocytes and follicle samples suggest a possible tropism of the N. caninum for the ovarian follicle. N. caninum has been identified by immunohistochemistry and PCR in liver, placenta, kidneys and brain, of aborted bovine fetuses and adults (Shivaprasad et al., 1989; Wouda et al., 1997). However, Wouda et al. (1997) reported that the distribution of N. caninum taquizoites, assessed by immunohistochemistry, is not equal among bovine tissues, preferring the brain (85%), to the liver (26%) and the heart (14%).
This study evaluated the presence of Neospora caninum in ovarian follicle aspirates and uterine flushes obtained from N. caninum seropositive dairy cows. Ninety-two cows that aborted within the previous 90 days were sampled to determine the presence of antibodies against N. caninum. Thirteen seropositive cows were chosen for collection of blood leukocytes, uterine flushes (UF; n = 12) and follicular aspirates (OPU; n = 13). Samples were centrifuged and the cellular sediment from the follicular fluid, uterine flushes and blood leukocytes were used for DNA extraction and PCR. Follicular aspirates had the highest frequency of DNA amplification for N. caninum (p < 0.05, 92.3%; 12/13). Whereas uterine (4/12) and blood leukocyte (5/13) samples had similar (p > 0.05) rate of positive results. Nonetheless, there was no agreement between blood leukocytes and follicular samples taken from the same animal (Cohen Kappa = −0.16). Similarly, blood leukocytes and uterine results had moderate agreement between them (Cohen Kappa = 0.47). This study indicates that N. caninum is present in the ovarian follicle and uterus of seropositive cows, suggesting a possible risk of neosporosis transmission between females during oocyte and embryo collection and transfer. Hence, precautions should be taken to minimize the risk of N. caninum transmission. Furthermore, the high incidence of positive results in follicle samples, that exceeded that of their paired blood leukocytes, suggests a possible tropism of N. caninum for the ovarian follicle.
First epidemiological study on exposure to Neospora caninum in different canine populations in the Algiers District (Algeria)
2009, Parasitology International
Citation Excerpt :
In farm dogs the seroprevalence reached 46.24%; a similar high seroprevalence in this type of dogs was also noticed by Lasri et al. [31] in Belgium. This is probably linked with the availability of infective material such as aborted fetuses and placentas [42,43]. This hypothesis is supported also by the high antibody titres recorded in farm dogs.
Neospora caninum is an important cause of abortion in cattle worldwide. Dogs act as final hosts shedding oocysts in the environment. They can also harbour the extraintestinal stage of the parasite and this may be associated with a fairly rare neuromuscular condition. The sera of 781 dogs from the Algiers District were screened by IFAT for the presence of anti-N. caninum antibodies. These dogs were distributed into four populations: local stray dogs, police dogs, dogs from breeding kennels and farm dogs. The overall seroprevalence was 21.90%. Significant differences were observed between the different populations, the highest prevalence being observed in farm (44.44%) and stray dogs (22.55%). Additionally, the highest titres were observed in farm dogs. Among studied epidemiological parameters, breed, dog origin, season and vaccination status were significantly associated with IFAT results. Additionally, a recently described real time PCR was used on the blood of 100 pound dogs and the results were compared with the serological data. A higher proportion of dogs was found to be positive by PCR when compared to the IFAT results. There was only a fairly low agreement between PCR and IFAT results which suggests that these techniques measured different aspects of the host–parasite relationship. This study indicates that the level of exposure of the canine population of Algiers area to N. caninum is very high. This would indicate a potentially high risk for N. caninum induced abortion in cattle in this region and in Algeria.
Pigeons (Columba livia) are a suitable experimental model for Neospora caninum infection in birds
2009, Veterinary Parasitology
Neospora caninum infections in chickens have been recently described by epidemiological and experimental approaches, and these birds may be considered natural intermediate hosts of the parasite. It has been postulated that other bird species might perform this role in wildlife as well. To better understand the sylvatic life cycle of N. caninum, further studies are required. In that sense, this work aimed to observe infection kinetics in pigeons experimentally infected with N. caninum. Experimental infections were conducted in parallel with a related protozoan, Toxoplasma gondii, which has been already described as able to infect pigeons in nature. Our results demonstrated that N. caninum disseminated through various tissues of this host and induced parasite-specific IgG seroconversion. Infection parameters were similar to that observed in the T. gondii infected group, although N. caninum-infected pigeons presented lower IgG titers during acute phase. The results herein described demonstrate that pigeons are a suitable model for N. caninum infection, considering that these data are in agreement with those observed in chickens experimentally infected with this parasite. As pigeons may be revealed as important reservoirs for N. caninum infection in nature, future studies are necessary to determine the real prevalence of this parasite in this and other birds in wildlife.

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^∗: Present address: Department of Avian and Aquatic Medicine, New York State College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, U.S.A.

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Veterinary Parasitology

Abstract

References (8)

Toxoplasma gondii infection of the central nervous system. Use of the peroxidase-antiperoxidase method to demonstrate Toxoplasma in formalin-fixed, paraffin embedded tissue sections

Human Pathol.

A review of toxoplasmosis in cattle

Vet. Parasitol.

Newly recognized fatal protozoan disease of dogs

J. Am. Vet. Med. Assoc.

Neonatal Neospora caninum infection in dogs: isolation of the causative organism and experimental transmission

J. Am. Vet. Med. Assoc.

Cited by (49)

Diagnosis and Control of Bovine Neosporosis

A review of Neospora caninum in water buffalo (Bubalus bubalis)

Characterization of the Inflammatory Response in the Uteri of Cows Infected Naturally by Neospora caninum

Increased incidence of DNA amplification in follicular than in uterine and blood samples indicates possible tropism of Neospora caninum to the ovarian follicle

First epidemiological study on exposure to Neospora caninum in different canine populations in the Algiers District (Algeria)

Pigeons (Columba livia) are a suitable experimental model for Neospora caninum infection in birds