Genetic characterisation of Neospora caninum strains from clinical samples of zebuine foetuses obtained in abattoirs in Goiás, Brazil

Occurrence of Atypical and New Genotypes of Toxoplasma Gondii in Free-Range Chickens Intended for Human Consumption in Brazil

Purpose

The aim of the present study was to detect and genotype T. gondii in free-range chickens destined to human consumption in Alagoas state, Brazil.

Methods

Two hundred blood samples were collected from free-range chickens and submitted to indirect immunofluorescence antibody test (IFAT). Brain tissue from 14 animals randomly selected were subjected to mouse bioassay. Positive samples in mouse bioassay were submitted to PCR and genotyped by PCR–RFLP.

Results

Out of two hundred blood samples from chickens, 72 (36%) samples were considered positive by IFAT. Two T. gondii strains were isolated, both being characterized as atypical and classified as #146 and a new genotype, named #279 in ToxoDB database.

Conclusions

Our results showed a sero-occurrence of T. gondii in free-range chickens intended for humans, and the genetic diversity of the parasite in Brazil, with a new genotype described.

Isolation of Neospora caninum from a beef cattle fetus from Argentina: Immunopathological and molecular studies

Neospora caninum is an important abortifacient agent affecting mainly cattle worldwide. The aim of the present work was to describe the histopathological findings in a naturally infected beef cow and its midterm fetus caused by a genetically defined N. caninum isolate in Argentina. A N. caninum seropositive multiparous Aberdeen Angus pregnant cow and its fetus in the sixth month of gestation were submitted for histopathological, immunohistochemical, serological, and molecular studies and parasite isolation. The cow belonged to a beef herd under extensive management, with a N. caninum seroprevalence of 11%, and low level of annual abortion rate (≤ 5%). The dam had mild lymphocytic infiltrate in CNS, heart and uterus and no parasites were detected by Immunohistochemistry (IHC). No parasitic DNA was detected in the dam's brain, and gamma interferon knockout mice inoculated with brain material did not become infected. Clusters of tachyzoites and parasitic DNA were detected in the placenta by IHC and PCR, respectively. However, isolation from the placenta was unsuccessful. The fetus developed specific antibodies and an inflammatory response was detected in multiple organs. Furthermore, in vitro and in vivo isolation was achieved from gamma interferon knockout mice inoculated with CNS from the fetus. Multilocus-microsatellite typing revealed a genetically defined N. caninum isolate similar to the previously reported as MLG 72. We report the first N. caninum isolate from beef cattle in Argentina.

Occurrence and genetic characterization of Toxoplasma gondii and Neospora caninum in slaughtered domestic rabbits in central China

Currently, information on the occurrence and genetic characterization of Toxoplasma gondii and Neospora caninum in tissues of rabbits in China is lacking. In this study, brain and heart samples from 470 slaughtered domestic rabbits were collected in Henan Province, Central China. The occurrence rate of T. gondii and N. caninum DNA detected by nested PCR was 2.8% and 2.1%, respectively. There were no significant differences (p > 0.05) in the frequency of the two parasite infections in relation to sex, breed, and region. Three out of 13 T. gondii-positive samples were completely or partially genotyped at 11 genetic markers using PCR-RFLP, and one was identified as ToxoDB genotype #9. For N. caninum, three different sequences at the ITS1 region and two genotypes at the MS5 microsatellite locus were identified. To our knowledge, this is the first genetic characterization of N. caninum isolates from rabbits.

Vertical transmission of Neospora caninum in bovine fetuses from a slaughterhouse in Brazil

Neospora caninum is considered as one of the main causes of reproductive failure in cattle. Vertical transmission is the main route of infection in the bovine host and plays an important role in maintaining the parasite in the herd. Molecular detection of N. caninum is important to determine the occurrence of the disease and to evaluate the genetic diversity of the parasite. The present study aimed at assessing the vertical transmission of N. caninum using molecular techniques to detect the parasite in tissue samples from bovine fetuses collected in a slaughterhouse in the state of São Paulo, Brazil. Seventy fetuses and 70 blood samples from pregnant cows were collected in a slaughtering line. Fresh samples of heart and brain tissue from fetuses were analyzed using molecular assays. Serum samples from fetuses and cows were subjected to an indirect fluorescent antibody test (IFAT) to detect antibodies against N. caninum. Nested PCR targeting the internal transcriber 1 (ITS1) region of the protozoan organism was used in the molecular testing. From the total of fetuses examined, 71.42% were positive for N. caninum by PCR. A higher number of heart samples (47.1%) were positive for the parasite using this technique. Antibodies against the protozoa were detected in 12.9% of serum samples of cows; 2.8% of fetuses were seropositive for this pathogen. Our results show that vertical transmission of N. caninum occurs in cattle from this region of Brazil, and that the use of different diagnostic techniques contributes to successful diagnosis of congenital transmission of the parasite in cattle.

Neospora caninum in properties in the west region of Paraná, Brazil: prevalence and risk factors

Abstract Neospora caninum is a heteroxenous protozoa, whose definitive hosts are canids and intermediate hosts are herbivores, and is of great importance in cattle. The objectives of this study were to determine the prevalence of N. caninum in dairy cattle and dogs, to detect the presence of the protozoa at the molecular level in aborted fetuses, and to identify the risk factors associated with infection in properties in the western region of the state of Paraná. For this study, 600 bovine serum samples from 60 properties, 163 canine serum samples from 52 properties and 17 bovine fetuses from nine properties were collected. Data were collected using an epidemiological questionnaire to verify the risk factors. Serum samples were analyzed using the indirect fluorescent antibody test. Fetal tissues were analyzed using polymerase chain reaction and subsequent DNA sequencing. Of the bovine samples, 23.67% were positive for N. caninum. Among the canine samples, 11.66% were positive for N. caninum. Risk factors in cattle were history of abortion, low milk production, extensive breeding, and Jersey breed (p<0.05). Protozoan DNA was detected in 52.94% of the 17 fetuses and the sequencing presented high similarity with N. caninum.

All about neosporosis in Brazil

Neospora caninum is protozoan parasite with domestic and wild dogs, coyotes and grey wolves as the definitive hosts and many warm-blooded animals as intermediate hosts. It was cultivated and named in 1988. Neosporosis is a major disease of cattle and has no public health significance. Since 1990's N. caninum has emerged as a major cause of abortion in cattle worldwide, including in Brazil. N. caninum also causes clinical infections in several other animal species. Considerable progress has been made in understanding the biology of N. caninum and there are more than 200 papers on this subject from Brazil. However, most of the reports on neosporosis from Brazil are serological surveys. Overall, little is known of clinical neosporosis in Brazil, particularly cattle. The few reports pertain to sporadic cases of abortion with no information on epidemics or storms of abortion. The objective of the present review is to summarize all reports from Brazil and suggest topic for further research, including prevalence of N. caninum oocysts in soil or in canine feces, and determining if there are additional definitive hosts, other than the domestic dog. There is need for a national survey in cattle using defined parameters. Future researches should focus on molecular characterization of N. caninum strains, possibility of vaccine production and relationship between wildlife and livestock epidemiology.

Isolation and molecular characterization of a new Neospora caninum isolate from cattle in Argentina

Neospora caninum is one of the most important causes of bovine abortion, but isolation of live parasites from infected tissue is difficult. The aims of the present study were to obtain new isolates of N. caninum from congenitally infected asymptomatic newborn cattle in Argentina and to perform characterization by multilocus-microsatellite analysis. Five clinically normal born calves, with demonstrable N. caninum antibodies in precolostrum serum by indirect fluorescent antibody test, were euthanized and their brain samples were processed for histopathological, immunohistochemical, polymerase chain reaction (PCR) analysis, and for bioassay in γ-interferon knockout (GKO) mice. Although N. caninum DNA was detected in brain from all the calves by PCR, viable N. caninum was isolated in GKO mice from only one calf. Neospora caninum tachyzoites of this Argentinean isolate, designated NC-Argentina LP1, were propagated in VERO cell cultures seeded with tachyzoites from the infected GKO mice tissues. Multilocus-microsatellite typing on DNA derived from cell cultured tachyzoites revealed a unique genetic pattern, different from reported isolates. This is the first bovine isolation and genetic characterization of N. caninum in Argentina.