• Korean Journal of Veterinary Service
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• v.30 no.2
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• pp.275-281
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• 2007

Neospora caninum (N caninum) is an intracellular protozoa parasite, and its infection is one of the important diseases because it can cause abortion in cattle. This study was conduct to gain epidemiological data for more effective control of the disease. Bloods were collected from 2,162 cattle on 90 farms from February to September 2006. Serums were tested for antibodies to N caninum using ELISA CherdCheck, IDEXX). The dairy breed presented a higher proportion of seropositive results than that of Hanwoo. The estimated proportion of N caninum-positive dairy farms was 71.1 %, but the overall seroprevalence was estimated as 22.8%. The seroprevalence of dairy cattle and Hanwoo were 31.0% and 4.9%, respectively. There was no significant difference in the seroprevalence by age, but the not-intensive managed farms had a high seroprevalence (OR=1.91, p-value<0.01). The antibody rate of cattle with dog(s) was greater than that of those without dogs (OR=2.13, p-value<0.01). There was a significant difference in abortion rate between seropositive cattle and seronegative ones (OR=6.2, p-value<0.01).

• Korean Journal of Veterinary Research
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• v.41 no.3
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• pp.381-385
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• 2001

Neospora caninum infections have been associated with neonatal paresis as well as abortion around the world. Bovine abortion induced by N caninum was first reported in 1997 in Korea. Diagnosis of N caninum infection is usually based on histopathology and immunohistochemical detection of organism. However, often the tissues having lesion suggestive of N caninum infection were negative on immunohistochemistry. Here, we describe establishment of PCR-based diagnostic strategy for N caninum infection using DNA extracted from paraffin blocks containing the lesion. PCR was able to amplify N caninum-specific bands from the paraffin blocks containing at least moderate degree of inflammation. Compared to paraffin-blocks, DNA extracted from fresh tissues were less sensitive than that of paraffin blocks. This PCR-based method can be practically applicable for rapid diagnosis of bovine N caninum infection with high specificity and sensitivity. Based on this method, 17% of bovine abortion surveyed during a designated period was associated with N caninum infection.

• Korean Journal of Veterinary Research
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• v.43 no.4
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• pp.677-681
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• 2003

Currently, both the indirect fluorescent antibody test (IFAT) and enzyme linked immunosorbent assay (ELISA) have been used to detect Neospora caninum antibodies. Several factors such as the buffers, the conjugate, the pattern of fluorescence, and the cross reactivity with other apicornplexan protozoan, may result in poorly correlated data. The present study was undertaken to develop and evaluate the Neospora agglutination test (NAT) for the detection and quantification of IgG antibodies to N. caninum from various animal species. Compared to the ELISA method, the NAT with a cutoff value of 1:512 gave a high index of coincidence (kappa=0.807) and no cross reactivity to Toxoplasma gondii antiserum. Hence, this NAT method, which did not require a species-specific secondary antibody and expensive tools, would be easily available for the detection of antibodies to N. caninllm of various animal species.

• Korean Journal of Veterinary Service
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• v.28 no.2
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• pp.99-106
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• 2005

This survey was carried out to investigate the seroprevalence of antibodies to Neospora caninum in Korean indigenous cattle that was representative livestock raised in Jeongeup province Jeonbuk Korea. A total of 1,162 sera were tested for N caninum antibodies using ELISA (Herdcheck anti-Neospora. IDEXX Laboratories Inc., Westbrook, Maine USA). $15(1.3\%)$ sera were positive by ELISA. A total of 290 farms were tested. $11(3.8\%)$ farms were positive. Among the seroprevalence of cattle according to the areas, 8 of 44 counties were infected N caninum. Sero-positive 11 farms of N caninum antibodies using ELISA test and 62 of 301 sera $(20.6\%)$ were infected to N caninum. We found that cattle be raised in Jeongeup province was slightly infected to N caninum. It seems to be infected of N caninum an early stage. but the positive rates was variable that it was $6\%\~62\%$. It was supposed to the highest positive rate of 3 farms had some factors to be infected. The factors were supposed to keep dogs yearly, located the base of hills, and almost feed with imported dried grass. Farmers suppose to the cause of abortion was not the neosporosis but also broke out an accident or was infected Brucella spp. The results of Brucella Rose Bengal Test (RBT) were all negative.

• Parasites, Hosts and Diseases
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• v.41 no.4
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• pp.243-245
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• 2003

Neospora caninum is an important cause of abortion in cattle, and dogs are its only known definitive host. Its seroprevalence among domestic urban and rural dogs and feral raccoon dogs (Nyctereutes procyonoides koreensis) in Korea was studied by indirect fluorescent antibody test (IFAT) and by the neospora agglutination test (NAT), respectively. Antibodies to N. caninum were found in 8.3% of urban dogs and in 21.6% of dogs at dairy farms. Antibody titers ranged from 1:50 to 1:400. Antibodies to N. caninum were found in six (23%) of 26 raccoon dogs. However, the potential role of raccoon dogs as a source of horizontal transmission of bovine neosporosis needs further investigation. The results of this study suggest that there is a close relationship between N. caninum infection among dairy farm dogs and cattle in Korea. This study reports for the first time upon the seroprevalence of N. caninum infection in raccoon dogs in Korea.

• Parasites, Hosts and Diseases
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• v.39 no.3
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• pp.241-246
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• 2001

The antigenic domain of the major surface protein (Nc-p43) of Neospora caninum was examined by polymerase chain reaction of its gene fragments and recombinant expression as GST fusion proteins. The fragments of Nc-p43 were as follow: a total open reading frame (OFR), T: OFR without signal sequence and C-terminal hydrophobic sequence, S: N-terminal 2/3 parts of S, A: C-terminal 2/3 parts, P; N-terminal 1/3 part, X: middle 1/3 part Y; and C-terminal 1/3 part, Z, respectively. The DNA fragments were cloned into pGEX-47 vector. Recombinant plasmids transformed into Escherichia coli of BL21 pLysS (DE3) strain were induced to express GST or GST fused fragments of Nc-p43 such as 69 kDa protein for T,66 kDa for S, 52 kDa for A,53 kDa for P, and 40 kDa proteins for X, Y, and Z, respectively in SDS-PAGE. The Nc-p43 fragments of T, S, and P reacted with a bovine serum of neosporosis while those of A, X, Y, and Z together with GST did not in the western blot. These findings suggest that the antigenic domain of Nc-p43 of N. caninum may be localized in the C-terminal 2/3 parts. Together with Al9 clone in SAGI of Toxoplasma gondii (Nam et at., 1996), the P fragment of Nc-p43 could be used as efficient antigens to diagnose and differentiate those infections with both species .

• Journal of Veterinary Clinics
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• v.27 no.6
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• pp.640-646
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• 2010

Neosporosis is a widespread parasitic disease caused by Neospora caninum, an intracellular protozoan parasite. It causes economic losses due to reproductive failure. The potential relationship between pregnancy outcomes and levels of IFN${\gamma}$, hormones, and antibodies in naturally N. caninum-infected cows was examined in the blood samples collected every 2 or 4 weeks in 26 pregnant cows from 4 different farms. The mean S/P value of seropositive nonaborting animals (n = 14) reached peak levels 15 weeks prior to parturition, and declined thereafter to parturition. The S/P value 13 weeks prior to abortion in seropositive aborting cows (n=3) remained at high levels, and abortions occurred at 20 (142 days), 26 (185 days), and 28 weeks (199 days) after artificial insemination. IFN${\gamma}$ levels in the seropositive non-aborting group varied by individuals and gestational periods; IFN${\gamma}$ levels stayed at elevated levels or increased abruptly close to abortion in seropositive aborting cows. IFN${\gamma}$ level patterns in the seronegative group (n = 9) were similar to the seropositive non-aborting group, although IFN${\gamma}$ amounts were lower than the seropositive group. The mean progesterone levels in the seropositive non-aborting and seronegative groups decreased markedly 7 weeks prior to parturition. The mean progesterone levels 5 and 7 weeks prior to abortion were lower than the other groups 5 and 7 weeks prior to parturition. The mean 17${\beta}$-estradiol levels in the seropositive aborting cows increased close to abortion; the produced amounts were lower than those of seropositive non-aborting and seronegative groups close to parturition. These results suggested that lower levels of progesterone and ${\beta}$-estradiol in Neospora-infected cows may lead to increases in IFN${\gamma}$ production and in turn may result in abortion.