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PubMed2003

Anti-parasitic activity of depudecin on Neospora caninum via the inhibition of histone deacetylase.

Neospora caninum is an apicomplexan parasite associated with abortion in cattle worldwide. Apicidin, histone deacetylase (HDAC) inhibitor, has shown a broad spectrum of anti-protozoal activity against apicomplexan parasites. Cultured vero cells infected with N. caninum tachyzoites were treated with 0.5 microg/ml of depudecin, another known natural product isolated from Altermaria brassiciicola with anti-histone deacetylase activity, to examine the efficacy of depudecin against intracellular multiplication of N. caninum tachyzoite, using 15 ng/ml of apicidin as the control. Depudecin significantly inhibited the intracellular multiplication of N. caninum at a level similar to that of apicidin without exerting any cytotoxicity on the host vero cells. Acid/urea/Triton gel electrophoresis analysis show anti-parasitic activity of depudecin appears to be due to the inhibition of protozoal histone deacetylase, which induces hyperacetylation of histones in N. caninum.

Alkadienes↗
PubMed2003

Prevalence of antibodies to Neospora caninum in dogs from Amazon, Brazil.

Neospora caninum is an important cause of abortion in dairy cattle worldwide. Dogs are important in the epidemiology of this parasite because they are the only hosts known to excrete N. caninum oocysts. Antibodies to N. caninum were assayed in serum samples from 157 dogs from Monte Negro, Rondônia, Amazon, Brazil using the indirect fluorescent antibody test. Antibodies to N. caninum were found in 13 (8.3%) of dogs in titers of 1:50 in 1, 1:100 in 2, 1:200 in 5, 1:800 in 1, 1:1600 in 2, and 1:3200 in 2 dogs. These data indicate that N. caninum infection is prevalent even in remote areas of the Amazon.

Age Factors↗
PubMed2003

The effect of the dam-calf relationship on serostatus to Neospora caninum on 20 Costa Rican dairy farms.

An epidemiological study was conducted on 20 dairy herds previously diagnosed as seropositive for Neospora caninum. The number of females per farm varies from 41 to 296. All females present on the farms were bled once in the period of July and August 2000. A total of 3002 females were bled. An indirect ELISA was used to determine the serostatus of the animals. The analysis of the data was performed in four steps: (1) descriptive statistics about the serological status and general characteristics of the cattle; (2) calculation of vertical and horizontal transmission; (3) an univariate analysis and, (4) a multivariate logistic regression analysis with herd as random effect. The within-herd seroprevalence varied between 25.0% (34/136) and 70.5% (203/288). Seven hundred and forty-seven dam-daughter pairs were available, involving daughters of any age. Daughters in the specific age-class of 2- and 3-years old had a higher seroprevalence (P<0.01) compared with younger and older age-classes. The risk of being seropositive when being born to a mother that tested seropositive (prevalence ratio (PR)) was 2.8-fold increased which coincides with a 5.3-fold increased odds. The probability of horizontal infection amounts to 0.22. The probability of a seropositive offspring due to vertical transmission was 0.64 (attributable fraction among exposed (AFexp)). The multivariate logistic regression showed a significant 6.0-fold increased odds for being seropositive when born from a seropositive mother. Also the within-herd seroprevalence level was significantly associated with the serostatus of the daughters. In the specific conditions of the dairy herds involved in this study, the serostatus of the cows should be not used as a predictor of the serostatus of daughters due to the increased probability of horizontal transmission.

Age Distribution↗
PubMed2003

Anti-protozoal efficacy of medicinal herb extracts against Toxoplasma gondii and Neospora caninum.

The purpose of this study was to determine whether alcohol extracts of herbs (Sophora flavescens Aiton, Sinomenium acutum (Thunb.) Rehder and E.H. Wilson, Pulsatilla koreana (Yabe ex Nakai) Nakai ex T. Mori, Ulmus macrocarpa Hance and Torilis japonica (Houtt.) DC.) from South Korea, possess in vitro anti-protozoal activity against cultures of Toxoplasma gondii and Neospora caninum. These herbs have been used as human anti-parasitics in Asian countries for many years. Alcohol extracts of these herbs were serially diluted to final concentrations ranging from 625 to 19.5 ng/ml in media and added to wells containing either T. gondii or N. caninum tachyzoites in equine dermal (ED) cells. Parasite growth inhibition was measured using 3H-uracil incorporation as compared to untreated controls. T. japonica inhibited T. gondii proliferation by 99.3, 95.5, 73.0 and 54.0% in the range from 156 to 19.5 ng/ml, and S. flavescens inhibited T. gondii proliferation by 98.7, 83.0 and 27.2% in the range from 156 to 39 ng/ml. T. japonica inhibited N. caninum proliferation by 97.8, 97.9, 85.3 and 46.4% in the range from 156 to 19.5 ng/ml. S. flavescens inhibited N. caninum proliferation by 98.6, 97.0, 69.5 and 14.0% in the range from 156 to 19.5 ng/ml. Toxicity to host cells was noted when concentrations of T. japonica and S. flavescens exceeded 625 ng/ml. The herb extracts from S. acutum, Pulsatilla koreana, and U. macrocarpa also showed toxicity at higher levels but did not achieve the same inhibition effects at the lower concentrations against T. gondii and N. caninum as T. japonica and S. flavescens.

Animals↗
PubMed2003

Antibodies to Neospora caninum in European brown hare (Lepus europaeus).

Neospora caninum antibodies in European brown hares (Lepus europaeus) were reported for the first time in sera collected from hares imported in Italy from East Europe. Sera from 93 hares coming from Hungary and 44 hares coming from Slovakia were tested using a direct agglutination test (DAT). Seroprevalence was 8.0% at the 1:40 dilution and 1.5% at 1:320 dilution. Seroprevalence in females and males and in different countries of origin did not differ significantly. Our results indicate that European brown hares are exposed to N. caninum. The low prevalence observed suggests a hares minimal exposure, but, considering that hares are common prey for foxes, it could be supposed that, also with a low prevalence, hares can be an important source of N. caninum infection in foxes.

Agglutination Tests↗
PubMed2003

Seroprevalence of Neospora caninum in aborting dairy cattle in the Czech Republic.

A serological survey for antibodies against Neospora caninum in aborting cattle was carried out in the Czech Republic. Serum samples from 463 aborting dairy cows originated from 137 farms from different parts of the Czech Republic were tested for presence of N. caninum antibodies by use of an enzyme-linked immunosorbent assay (ELISA) and an indirect fluorescent antibody test (IFAT). Antibodies (> or = 1:640) to N. caninum were found in 18 (3.9%) of 463 aborting cows. Farm prevalence in aborting cows was 12.4% (17/137). The antibody titres of cows were 1:200 (9 cows), 1:640 (7 cows), 1:1280 (3 cows), 1:2560 (3 cows), 1:5120 (3 cows), 1:10,240 (2 cows) and 1:20,480 (0 cow). A case-control study was conducted to estimate the association of N. caninum infection and abortion. For this 407 serum samples were collected from cows on five dairy farms with repeated occurrence of endemic and sporadic abortion of unidentified etiology. These samples were obtained from aborting cattle (n=44) and normally calving cattle (control group; n=363) and tested for N. caninum antibodies by an immunofluorescent antibody test (IFAT). Overall, 3.19% (13/407) of cows sampled had positive N. caninum fluorescence with a cut-off titre of 1:200. The prevalence of N. caninum was significantly higher (P<0.05) in the aborting group (13.64%; 95% confidence interval (CI): 5.2, 27.4) than in the control group (1.93%; 95% CI: 0.8, 3.9). A strong association between seropositivity and abortion was found, with seropositive cows being eight times more likely to abort than seronegative cows (odds ratio=8; 95% CI: 2.6, 25.1). This first report on the serological prevalence of N. caninum in cows in the Czech Republic verified a strong association between N. caninum infection and abortions in five dairy farms. Thus, the neosporosis should be considered in differential diagnosis of bovine abortion.

Abortion, Veterinary↗
PubMed1996

A review of Neospora caninum and neosporosis.

Neospora caninum is a recently recognized protozoan parasite of animals, which until 1988 was misidentified as Toxoplasma gondii. Its life cycle is unknown. Transplacental transmission is the only recognized mode of transmission. It has a wide host range, but its zoonotic potential is unknown. Neosporosis is a major cause of abortion in cattle in many countries. It is also an important cause of neuromuscular paralysis in dogs. This paper reviews information on parasite structure, life cycle, biology, clinical signs, diagnosis, treatment and control.

Abortion, Veterinary↗
PubMed1997

Efficacy of decoquinate against Neospora caninum tachyzoites in cell cultures.

Neospora caninum is a major cause of abortion in dairy cattle in the United States and other countries. Abortions and neonatal mortality also occur in other ruminant species. Decoquinate is an anticoccidial that is approved for use in cattle and goats in the United States. We studied the efficacy of decoquinate against tachyzoites of N. caninum in a 5-day of treatment, cell culture flask lesion-based assay. Decoquinate killed tachyzoites at concentrations of 0.1 and 0.01 microgram ml-1. Decoquinate had little measurable effect on extracellular tachyzoites. Decoquinate acted quickly to kill intracellular stages at coccidiocidal concentrations; tachyzoites were killed within 5 min at 0.1 microgram ml-1 decoquinate.

Abortion, Veterinary↗
PubMed1997

An indirect enzyme-linked immunoassay (ELISA) for demonstration of antibodies to Neospora caninum in serum and milk of cattle.

An indirect enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to Neospora caninum in serum from cattle is described. Extracted tachyzoite proteins incorporated into immunostimulating complexes (iscoms) were used as coating antigen and a mouse monoclonal antibody to bovine immunoglobulin G1 as conjugate. Western blot analysis of the iscom preparation revealed a restricted number of antigens compared with whole parasite homogenates. When probed with a serum from an experimentally infected calf, heavily stained antigens with apparent molecular masses of 28, 35, 45 and 78 kDa were seen. The sensitivity and specificity of the ELISA was 100% and 96%, respectively, against an indirect fluorescent antibody test as indicator of true status. The applicability of the ELISA for demonstration of antibodies in milk was evaluated and the agreement between serum and milk ELISA was 95%.

Animals↗
PubMed1998

Prevalence of antibodies to Neospora caninum and Toxoplasma gondii in cattle and water buffaloes in southern Vietnam.

Serum samples from 200 dairy cattle and 200 beef water buffaloes were collected in southern Vietnam during May to September 1995. The sera were analysed for antibodies to Neospora caninum by an enzyme-linked immunosorbent assay and the indirect fluorescent antibody test, and for antibodies to Toxoplasma gondii by the direct agglutination test. Significant levels of N. caninum antibodies were detected in 5.5% of the cattle sera and in 1.5% of the water buffalo sera. 10.5% of the cattle sera and 3% of the water buffalo sera were found to contain T. gondii antibodies. Two of the cattle sera had both T. gondii and N. caninum antibodies. The present communication is the first to report serological evidence of N. caninum infection in the water buffalo.

Agglutination Tests↗
PubMed1998

Prevalence of Neospora caninum and Toxoplasma gondii antibodies in sera from camels from Egypt.

Sera from camels from Egypt were examined by the direct agglutination tests incorporating mercaptoethanol for antibodies to Neospora caninum and Toxoplasma gondii. Antibodies to N. caninum were found in 6 of 161 camels in titers of 1:40 (2 camels) and 1:80, 1:160, 1:640, and 1:1280 in 1 camel each, using N. caninum formalin preserved whole tachyzoites as antigen. Antibodies to T. gondii were found in 17.4% of 166 camels in titers of 1:25 (3 camels), 1:50 (18 camels). and > 1:500 (8 camels) using T. gondii tachyzoites. All 6 camels with N. caninum antibodies had no T. gondii antibodies in 1:4 dilution of serum, indicating specificity of the reaction. This is the first report of N. caninum prevalence in Egypt.

Agglutination Tests↗
PubMed1998

Neospora caninum infection in a Bernese cattle dog from Italy.

A cutaneous nodule associated with Neospora caninum infection was diagnosed in a 5-year-old male Bernese cattle dog from Italy. The ulcerative lesion was 2-3 cm wide located in the skin of the tarsal region. Haematological values were normal and the dog did not show any neurological abnormalities. The dermal lesion consisted of a diffuse necrotic dermatitis with a dense infiltrate of mostly neutrophils and macrophages, surrounded by a fibrous wall. Histological sections revealed numerous tachyzoites of N. caninum scattered throughout the tissue. Diagnosis was confirmed both by immunohistochemical staining and electron microscopic examination. The dog had a 1:640 IFAT titre to N. caninum. Four weeks after surgical excision new subcutaneous nodules reappeared. The cutaneous lesions resolved following 21 days of therapy with clindamycin hydrochloride. These observations demonstrate the presence of N. caninum in Italy and confirm that neosporosis should be considered in the differential diagnosis of pyogranulomatous dermatitis in dogs. Clindamycin may be an effective treatment for cutaneous neosporosis.

Animals↗
PubMed1998

Neospora caninum-associated equine protozoal myeloencephalitis.

Equine protozoal myeloencephalitis (EPM) was clinically diagnosed in a 20-year-old horse with severe ataxia. The cerebrospinal fluid was positive for Sarcocystis neurona antibodies by western blot. The horse was administered corticosteroids to facilitate in vitro culture of S. neurona from its spinal cord following necropsy. Microscopic lesions of EPM were present in the brain and in the spinal cord, including multifocal inflammatory cellular infiltrates and several large groups of protozoa. Immunohistochemical, and light and electron microscopic examinations revealed that the protozoa were Neospora caninum and not S. neurona. The protozoa divided by endodyogeny, tachyzoites had rhoptries, and organisms reacted specifically to N. caninum antibodies. Veterinarians should be aware of increasing diagnosis of N. caninum as another etiological agent responsible for the lesions of EPM.

Animals↗
PubMed1998

The efficiency of vertical transmission of Neospora caninum in dairy cattle analysed by serological techniques.

The association of Neospora caninum infections with cattle families was examined in a dairy cattle herd with sporadic abortions using three different serological tests. Cattle seropositive for N. caninum clustered in six families, three of which encountered abortions. In absence of age-related differences in the N. caninum seroprevalence, the family association of N. caninum infection indicated that congenital infection represented the predominant route of transmission in this herd. Fourteen (93%) out of 15 descendants of 10 seropositive cows were seropositive themselves. Only one female calf of a seropositive cow remained seronegative and gave birth to a calf which was tested seronegative again. Only one seronegative cow that had two seronegative descendants also gave birth to one seropositive calf. This was the only indication for potential postnatal transmission that occurred in the herd. The results of this study suggest that the N. caninum-infection can be maintained over several generations at a nearly constant prevalence level, apparently without a need for dispersion by an definitive host.

Abortion, Veterinary↗
PubMed1999

Prevalence of antibodies to Neospora caninum in dogs.

Serum samples from 1077 dogs suspected of having Neospora caninum infections from 35 states in the United States and 3 provinces in Canada were tested for N. caninum IgG antibodies by the indirect fluorescent antibody test. Antibodies to N. caninum were found in 75 of 1077 (7%) of the samples. Twenty of the positive dogs were females, 17 were males and the sex was not recorded on 38 dogs. Chi square analysis indicated no differences (P > 0.05) based on sex were present. Dogs from the Southeast and Midwest regions of the United States were more likely to be N. caninum antibody positive than were dogs from the Northeast or West regions.

Animals↗
PubMed1999

Serum antibody profile and reproductive performance during two consecutive pregnancies of cows naturally infected with Neospora caninum.

The objective of this study was to record how the antibody levels change over time during pregnancy in dairy cows naturally infected with the protozoan parasite Neospora caninum, and relate this to the reproductive performance. Eighteen cows with antibodies to N. caninum were serum sampled monthly during their first pregnancy and 13 of them were also followed for a second pregnancy. In all, five pregnancies ended in abortion and two in stillbirth. Antibodies to N. caninum in serum were demonstrated by immune stimulating complex enzyme-linked immunosorbent assay (iscom ELISA). The N. caninum antibody titres remained well above the 1:100 cut-off limit for the test used during 2 years in all cows. In the non-aborting cows, mean values of antibody titres to N. caninum rose 1.5-2.5 dilution steps to reach a plateau 4-5 months before parturition, and thereafter decreased from 2 months before parturition. These changes were statistically significant (p < 0.001). The same pattern was seen in the aborting cows. The consistent pattern of rise in antibody titres observed during both pregnancies in all cows indicated a reactivation rather than a reinfection of the parasite at mid-gestation.

Animals↗
PubMed1999

Prevalence of antibodies to Sarcocystis neurona, Toxoplasma gondii and Neospora caninum in horses from Argentina.

Sera from 76 horses from Argentina were examined for antibodies to Sarcocystis neurona, Toxoplasma gondii and Neospora caninum. Antibodies to S. neurona were found in 27 (35.5%) of 76 horses using immunoblots with culture derived merozoites as antigen. Antibodies to T. gondii were found in 10 (13.1%) of 76 horses by using the modified agglutination test with formalin-fixed tachyzoites and mercaptoethanol; titers were 1:25 (two horses), 1:50 (six horses), 1:100 (two horses), and 1:200 (one horse). Antibodies to N. caninum were not found in any of the 76 horses by the use of N. caninum agglutination test. This is the first report of S. neurona infection in horses in Argentina.

Agglutination Tests↗