Immunogenicity, safety and dual DIVA-like character of a recombinant candidate vaccine against neosporosis in cattle.

Neosporosis is the major infectious cause of abortion and reproductive losses in cattle worldwide; however, there are no available vaccines or drugs to control this disease. Recently, a dual (positive and negative) DIVA-like (Differentiation of Infected from Vaccinated Animals) vaccine was evaluated in a pregnant mouse model of neosporosis, showing promising immunogenic and protective results. The current report aimed to study the safety, the dose-dependent immunogenicity and the dual DIVA-like character of a recombinant subunit vaccine composed of the major surface antigen from Neospora caninum (rNcSAG1) and the carrier/adjuvant Heat shock protein 81.2 from Arabidopsis thaliana (rAtHsp81.2) in cattle. Healthy heifers were separated and assigned to experimental groups A-F and subcutaneously immunized with 2 doses of vaccine formulations 30 days apart as follows: A (n = 4): 50 µg rNcSAG1 + 150 µg rAtHsp81.2; B (n = 4): 200 µg rNcSAG1 + 600 µg rAtHsp81.2; C (n = 4): 500 µg rNcSAG1 + 1,500 µg rAtHsp81.2; D (n = 3): 150 µg rAtHsp81.2; E (n = 3):1,500 µg rAtHsp81.2, and F (n = 3) 2 ml of sterile PBS. The immunization of heifers with the different vaccine or adjuvant doses (groups A-E) was demonstrated to be safe and did not modify the mean value of the evaluated serum biomarkers of metabolic function (GOT/ASP, GPT/ALT, UREA, Glucose and total proteins). The kinetics and magnitude of the immune responses were dose-dependent. The higher dose of the vaccine formulation (group C) stimulated a broad and potent humoral and cellular immune response, characterized by an IgG1/IgG2 isotype profile and IFN-γ secretion. In addition, this was the first time that dual DIVA-like character of a vaccine against neosporosis was demonstrated, allowing us to differentiate vaccinated from infected heifers by two different DIVA compliant test approaches. These results encourage us to evaluate its protective efficacy in infected pregnant cattle in the future.

PRESENCE OF ANTI-NEOSPORA CANINUM ANTIBODIES IN TEMAZATE DEER (MAZAMA TEMAMA) AND WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) FROM THE CENTRAL REGION OF VERACRUZ, MEXICO.

This study documents the presence of anti-Neospora caninum antibodies and their association with certain risk factors in 2 deer species from the central region of Veracruz State, Mexico. A total of 90 blood samples, 20 from temazate deer (Mazama temama) and 70 from white-tailed deer (Odocoileus virginianus), were taken from 3 farms, and serum samples were subjected to ELISA indirect test to detect N. caninum antibodies; the association between the serological status and the possible risk factors was then estimated. The overall presence of anti-N. caninum antibodies was 57.7% (52/90; 95% CI 46.9-67.9), with positive animals identified on all farms; in white-tailed deer it was 57% and in temazate deer 60%. Prevalence was higher in females than males. Adult animals had a higher prevalence than young ones. The risk analysis identified the age in the adult animal category (odds ratio 5.8) as being associated with the presence of anti-N. caninum antibodies. These results provide evidence of the significant contamination of oocysts in the environment and allow us to estimate the contribution of deer to the sylvatic cycle.

A first insight into seropositivity of Neospora caninum and associated risk factors in free-roaming dogs from Ecuador.

Neosporosis is a worldwide parasitic disease caused by the protozoan Neospora caninum. It can cause economic losses to farmers due to its relationship with abortions and neonatal mortality in cows. Dogs play a key role in its spread as they are considered definitive hosts. In this study, we determined for the first time the seropositivity of N. caninum infection in dogs from Ecuador and evaluated potential risk factors. A total number of 339 free-roaming dogs from the three main regions of Ecuador (Coastal, Andean, and Amazonian regions) were included in the study and classified either as urban or rural dogs. Serum samples were collected from November 2018 to May 2019, and analyzed with a commercial ELISA test. An overall seropositivity of 6.8 % (CI: 95 %, 2.8 % - 11.7 %) was found in N. caninum infection with no statistical differences among regions or urban/rural dogs. This is the first surveillance of N. caninum in Ecuador, confirming a country-wide distribution of this pathogen. Considering the large populations of free-roaming dogs in Ecuador, a One Health approach for surveillance and managing N. caninum in dogs is needed to protect either livestock or wildlife.

The role of genetic variability of the host on the resistance to Neospora caninum infection in cattle.

Neospora caninum is one of the most frequently diagnosed abortifacient pathogens in cattle. There is abundant genomic information about the parasite itself, but very little is known about the genetic variability of resistance in the most common intermediate host. The aim of this review was to compile all the available information about the genetic variability associated with the resistance to N. caninum both between and within cattle breeds. We systematically searched for published studies that investigated the influence of genetics of the host on the prevalence of N. caninum and risk of abortion. Beyond the potential confounding effects of feeding systems, management and animal density, some lines of evidence suggest that Holstein, the most popular breed for milk production, has a comparatively higher risk of abortion due to infections by N. caninum, whereas some beef breeds from Continental Europe seem to be more resistant. It is still not clear if different genetic mechanisms of resistance are involved in the two known routes of infection: postnatal ingestion of oocysts or transplacental transmission from the infected dam to the fetus. Genomic information associated with susceptibility to infection and risk of abortion in different cattle breeds is still scarce. The information reported here could be useful to identify new research alternatives and to define novel strategies to deal with this major problem of animal production.

Epidemiology of Neospora caninum and Toxoplasma gondii infection in venison from Aguascalientes, Mexico.

The objective of the study was to estimate the seroprevalence of Neospora caninum and Toxoplasma gondii in venison from Aguascalientes, Mexico, their possible association with some risk factors, and to identify the presence of parasite DNA in blood and tissues. For this study, 5 farms and four species of venison were included, where 43 blood serum samples were obtained and in 37 of these animals a peripheral blood sample was also obtained; from hunted deer, 6 liver and 2 heart samples were obtained. The samples were analyzed by ELISA and PCR tests, respectively. The association between the serological status and the possible risk factors was estimated. The overall seroprevalence in N. caninum was 47% (20/43; CI 95% 31-62), with positive animals in all farms in a range of 18 to 100%, while for T. gondii it was 49% (21/43; CI 95% 33-64), with positive animals in 80% of farms in a range of 18 to 100%. The prevalence of N. caninum DNA detection in blood was 59% (22/37; CI 95% 42-74), with positive animals in all farms, in a range of 45 to 100%, while in T. gondii it was 76% (28/37; CI 95% 58-87), with positive animals in all farms, in a range of 56 to 100%. Age (> 4 years) was identified as associated with seroprevalence in N. caninum (OR 5.2) and in T. gondii (OR 12.7). DNA from both parasites was detected in the liver and heart samples. The results shown that venison populations included in the study are living in an environment highly contaminated with oocysts excreted by the definitive host.

EPIDEMIOLOGY OF TOXOPLASMA GONDII AND NEOSPORA CANINUM INFECTION IN GOATS FROM AGUASCALIENTES, MEXICO.

The objective of this study was to describe the epidemiology of Toxoplasma gondii and Neospora caninum infection by estimating seroprevalence and its association with certain risk factors in goats from Aguascalientes, Mexico. A total of 150 blood samples was taken from 10 farms and serum samples were subjected to enzyme-linked immunosorbent assay indirect test to detect T. gondii and N. caninum antibodies; the association between seroprevalence and some potential risk factors was estimated through logistic regression analysis. The general seroprevalence for T. gondii was 12.6%, observed in the farms in a range of 6.6 to 60%, finding seropositive animals in 80% of them; for N. caninum the seroprevalence was 3.3% and in farms a range of 6.6 to 13.3% was identified and 30% of them had at least 1 seropositive animal. The coinfection was 0.66%. The risk analysis for T. gondii identified a history of abortions (odds ratio 9.25) as a factor associated with seroprevalence; for N. caninum, no risk factor was identified.

Immunisation with Neospora caninum subunits rsNcSAG4 and rsNcGRA1 (NcSAG4 and NcGRA1 epitopes construct) in BALB/c mice: the profile of the immune response and controlling the vertical transmission.

Neospora caninum is an apicomplexan protozoan that causes neosporosis, which has a high economic impact on cattle herds with no available vaccine. During infection, the secretion of dense granules and the expression of surface antigens play an important role in hosting immunomodulation. However, some epitopes of those antigens are immunogenic, and using these fractions could improve the subunit antigens in vaccine design. This study evaluates the recombinant peptides rsNcGRA1 and rsNcSAG4 derived from NcGRA1 and NcSAG4 native antigens as vaccine candidates produced by a fermentative process in the yeast culture system of Komagataella phaffii strain Km71, confirmed by colony PCR, SDS-PAGE, and western blotting. The assay was conducted in BALB/c mice using the peptides at low (25 µg) and standard (50 µg) dosages in monovalent and combined administrations at three time points with saponin as an adjuvant assessing the immunogenicity by antibodies response and cytokine production. We challenge the females after pregnancy confirmation using 2 × 105 NC-1 tachyzoites previously propagated in Vero cells. We assessed the chronic infection in dams and vertical transmission in the offspring by PCR and histopathology. Mice, especially those immunised with combined peptides and monovalent rsNcGRA1 at a standard dose, controlling the chronic infection in dams with the absence of clinical manifestations, showed an immune response with induction of IgG1, a proper balance between Th1/Th2 cytokines and reduced vertical transmission in the pups. In contrast, dams inoculated with a placebo vaccine showed clinical signs, low-scored brain lesions, augmented chronic infection with 80% positivity, 31% mortality in pups, and 81% vertical transmission. These findings indicate that rsNcGRA1 peptides in monovalent and combined with rsNCSAG4 at standard dose are potential vaccine candidates and improve the protective immune response against neosporosis in mice.

Dysfunction, oxidative stress markers, and cytokine expression in the placentae of mice experimentally infected with Neospora caninum.

Neosporosis is the major cause of abortion and reproductive failures in cattle, leading to significant economic losses. In this study, we evaluated the impact of Neospora caninum infection on oxidative stress (OS) markers and local cytokine mRNA expression at the placenta, as well as its effect on the progesterone (P4) serum levels and systemic cytokine profile in a pregnant mouse model. Infected pregnant mice (NC-1 group) showed increased percentages of fetal losses and IFN-γ serum levels, decreased serum progesterone, increased placental mRNA expression levels of both Th1-type (IFN-γ and TNF-α) and Th2-type (IL-4) cytokines, and inhibited expression of TGF-ß1 (Treg) compare to control dams (CONTROL group). In addition, lipid peroxidation and ROS were increased, whereas the antioxidant enzymes, superoxide dismutase (SOD), and catalase (CAT) activities were modified in the placentae of infected mice compared to control mice. These findings demonstrate that multiple factors, including placental OS, are involved in fetal losses associated with N. caninum infection in mice, thus OS contribution to the placental physiopathology of neosporosis in other hosts must not be ruled out.

New insights into phenotype and genotype relationships in Neospora caninum.

The successful isolation of four new Neospora caninum strains from different regions and with different backgrounds (obtained from an abortion storm or congenitally infected and asymptomatic calves) allowed us previously to characterize natural isolates, finding differences in phenotype and microsatellites. Given the variability observed, we wondered in this work whether these differences had consequences in virulence, invasion and vertical transmission using cell cultures and murine neosporosis models. In addition, we performed the genomic analysis and SNP comparative studies of the NcURU isolates. The results obtained in this work allowed us to establish that NcURU isolates are of low virulence and have unique phenotypic characteristics. Likewise, sequencing their genomes has allowed us to delve into the genetic singularities underlying these phenotypes, as well as the common mutated genes. This work opens a new perspective for diagnostic purposes and formulating possible vaccines based on attenuated strains.

A new cyclodipeptide from Tetragonisca angustula honey active against Neospora caninum and in silico study.

A new cyclic natural compound formed by succinic acid and two alanine amino acid units was isolated from the Tetragonisca angustula honey extract. The chemical structure of 1 was established based on spectroscopic data analysis, including one- (1H and 13C NMR) and two-dimensional NMR techniques (1H-1H-COSY, HSQC and HMBC). A primary culture model previously infected with Neospora caninum was used to evaluate 1 for two time intervals (24 and 72 h), showing a reduction (40-56%) of the number of tachyzoites in the first 24 h and until 72 h, a dose-dependent reduction in parasite proliferation (25-50%). Glial cells treated with 1 did not demonstrate toxicity at concentrations up to 25 ug/mL. Treated and infected cultures showed an increase in NO when compared to control cells in 24 h and 72 h. In silico studies suggest that the new compound may affect DNA synthesis and impair -protein production.

Epidemiological evaluation of Neospora caninum in dairy animals.

The purpose of the study is to explore the epidemiological information concerning the spread of neosporosis in the Moscow region (Russian Federation) and Almaty region (Republic of Kazakhstan). The study is conducted in 2019 in the Moscow region (Russian Federation) and Almaty region (Republic of Kazakhstan). The study sample includes 800 cows (400 animals at each of the two locations), 100 at each of the 4 cattle farms in the Moscow region and 100 at each of the 4 cattle farms in the Almaty region. There were more seropositive cows on the rest of farms as compared to farm No. 1: 1.9 times more on farm No. 2 (p ≤ 0.01), 2.4 times more on farm No. 3 (p ≤ 0.001), and almost 4 times more on farm No. 4 (p ≤ 0.0001). In terms of the abortion rates, the maximum difference between the farms was 5-fold in the Moscow region (p ≤ 0.0001) and 3-fold in the Almaty region (p ≤ 0.001). Positive correlations exist between all the studied parameters (the proportion of seropositive animals, the proportion of seroprevalent animals, the abortion rate, and the stillbirth rate). The results of the study are mainly extremely valuable for the global economy, because the Republic of Kazakhstan and the Russian Federation occupy an important place in the export of meat and dairy products.

Neosporosis in Argentina: Past, present and future perspectives.

Neosporosis, caused by the protozoan Neospora caninum, was first diagnosed in Argentinean cattle in the 90's. With a national bovine stock of approximately 53 million head, the cattle industry is socially and economically relevant. Severe economic losses have been estimated at US$ 33 and 12 million annually in dairy and beef cattle, respectively. Approximately 9% of bovine abortions in the Buenos Aires province are caused by N. caninum. In 2001, the first isolation of N. caninum oocysts from feces of a naturally infected dog was performed in Argentina and named as NC-6 Argentina. Further strains were isolated from cattle (NC-Argentina LP1, NC-Argentina LP2) and axis deer (Axis axis, NC-Axis). Epidemiological studies revealed a high distribution of Neospora-infections not only in dairy but also in beef cattle, with seroprevalence rates of 16.6-88.8% and 0-73%, respectively. Several experimental infection studies in cattle have been carried out, as well as attempts to develop effective vaccines to avoid Neospora-abortions and transmission. However, no vaccine has proven successful for its use in daily practice. Reduction of seroprevalence, vertical transmission and Neospora-related abortions have been achieved in dairy farms by the use of selective breeding strategies and embryo transfer. Neospora-infections have been also detected in goats, sheep, deer, water buffaloes (Bubalus bubalis) and gray foxes (Lycalopex griseus). Moreover, Neospora-related reproductive losses were reported in small ruminants and deer species and could be more frequent than previously thought. Even though diagnostic methods have been improved during the last decades, control of neosporosis is still not optimal. The development of new strategies including new antiprotozoal drugs and vaccines is highly needed. This paper reviews the information from the previous 28 years of research of N. caninum in Argentina, including seroprevalence and epidemiological studies, available diagnostic techniques, experimental reproduction, immunization strategies, isolations and control measures in domestic and non-domestic animals from Argentina.

Spatial distribution and evaluation of risk factors for bovine neosporosis in Rondônia, Brazil / Distribuição espacial e avaliação dos fatores de risco para neosporose bovina em Rondônia, Brasil

Neospora caninum is an important worldwide parasite responsible for causing abortion in animals. Due to limited information on the occurrence of infection by this parasite in the state of Rondônia, Brazil, this study aimed to determine the seroprevalence and identify the risk factors associated with the infection in slaughtered cattle, from 19 municipalities distributed in seven microregions of the state. A total of 494 samples were obtained and subjected to anti-N. caninum antibodies, using the Indirect Immunofluorescence Reaction technique. Antibodies were detected in 5.06% (25/494) of the samples, in 30.30% (10/33) of farms, in nine municipalities located in four microregions of Rondônia. Of all the animals analyzed, 4.81% of the females (20/416) and 6.41% of the males (05/78) were seropositive for the parasite, with "abortion in the last 12 months" being considered an important risk factor for the occurrence of infection (OR = 9.54; p = 0.01). The present study points out the prevalence of anti-N. caninum antibodies in 5.06% of slaughtered animals and abortion as the main risk factor associated with infection by N. caninum, thus contributing to the elucidation of the epidemiology of this protozoan in Rondônia, Brazil.

Neospora caninum é um importante parasito, responsável por causar aborto em animais e distribuído mundialmente. Devido às informações limitadas sobre a ocorrência da infecção por esse parasito no estado de Rondônia, Brasil, este estudo teve como objetivo determinar a soroprevalência e identificar os fatores de risco associados à infecção em bovinos abatidos, oriundos de 19 municípios, distribuídos em sete microrregiões do estado. Um total de 494 amostras foi obtido e submetido à pesquisa de anticorpos anti-N. caninum, por meio da técnica de reação de imunofluorescência indireta. Os anticorpos foram detectados em 5,06% (25/494) das amostras, em 30,30% (10/33) das propriedades rurais, de nove municípios, localizados em quatro microrregiões de Rondônia. De todos os animais analisados, 4,81% das fêmeas (20/416) e 6,41% dos machos (05/78) foram soropositivos para o parasito, sendo o "aborto nos últimos 12 meses" considerado um importante fator de risco para a ocorrência da infecção (OR = 9,54; P = 0,01). O presente estudo aponta a prevalência de anticorpos anti-N. caninum em 5,06% dos animais abatidos e o aborto como o principal fator de risco associado à infecção por N. caninum, contribuindo assim para a elucidação da epidemiologia desse protozoário em Rondônia, Brasil.

Aborto em bovinos e bubalinos: causas específicas e inespecíficas / Abortion in cattle and buffaloes: specific and non-specific causes

O aborto é caracterizado como a expulsão do feto sem viabilidade para fora do ambiente uterino da progenitora durante o período que vai do 42° dia a o 260° dia. São descritos diversos fatores infecciosos e não infecciosos como etiologia para o aborto. Dentre os infecciosos, destacam-se as infecções por bactérias, vírus, protozoários e fungos. Enquanto as causas não infecciosas englobam falhas de manejo nutricional, intoxicações e medicamentos que ocasionalmente podem levar à morte fetal. Essa mortalidade fetal é causa importante de perdas reprodutivas na cadeia produtiva de animais domésticos, especialmente bovinos e bubalinos. Ambas as espécies participam da produtividade econômica no Brasil e compartilham de diversas doenças que são causas de aborto. Nesse contexto, o objetivo desta revisão foi reunir e discorrer sobre as principais informações concernentes às possíveis etiologias do aborto, sejam elas de origem infecciosa ou não infecciosas nas espécies bovinas e bubalinas no Brasil.

Abortion is characterized as the expulsion of the non-viable fetus outside the mother's uterine environment during the period between the 42nd day to the 260th day. Several infectious and non-infectious factors are described as etiology for miscarriage. Among the infectious, infections by bacteria, viruses, protozoa, and fungi stand out, while non-infectious causes include failures in nutritional management, poisoning, and medications that occasionally can lead to fetal death. This fetal mortality is an important cause of reproductive losses in the production chain of domestic animals, especially cattle and buffaloes. Both species participate in economic productivity in Brazil and share several diseases that are causes of abortion. In this context, this review aimed to gather and discuss the main information concerning the possible etiologies of abortion, whether of infectious or non-infectious origin in bovine and buffalo species in Brazil.

Insights into the Cell Division of Neospora caninum.

Neospora caninum is an apicomplexan protozoan parasite responsible for causing neosporosis in a range of animal species. It results in substantial economic losses in the livestock industry and poses significant health risks to companion and wild animals. Central to its survival and pathogenicity is the process of cell division, which remains poorly understood in this parasite. In this study, we explored the cell division of Neospora caninum using a combination of modern and classic imaging tools, emphasizing its pivotal role in perpetuating the parasite's life cycle and contributing to its ability to persist within host organisms. We described the intricacies of endodyogeny in Neospora caninum, detailing the dynamics of the cell assembly and the nuclear division by ultrastructure expansion microscopy and regular confocal microscopy. Furthermore, we explored the centrosome dynamics, the centrioles and the apicoplast through the advancement of the cell cycle. Our analysis described with unprecedented detail, the endodyogeny in this parasite. By advancing our understanding of these molecular mechanisms, we aimed to inspire innovative strategies for disease management and control, with the ultimate goal of mitigating the devastating impact of neosporosis on animal health and welfare.

Anti-Toxoplasma gondii and anti-Neospora caninum antibodies in dogs with and without neurological signs / Anticorpos anti-Toxoplasma gondii e anti-Neospora caninum em cães com e sem sinais neurológicos

This study investigated the association between neurological signs as well as plausible risk factors and the seroprevalence of Toxoplasma gondii and Neospora caninum infection in dogs of the Campo Grande region of Mato Grosso do Sul, Brazil. In this study, the dogs were divided into two groups based on the presence and the absence of neurological signs (n=30 in each group). Serological diagnosis was performed using the indirect fluorescent antibody test. In the group with neurological disorders, 23.3% and 30% of the dogs had anti-T. gondii and anti-N. caninum antibodies, respectively. Moreover, three dogs from this group showed co-infection with both protozoa. In the group without neurological signs, 16.7% and 13.3% of the dogs were seropositive for T. gondii and N. caninum, respectively. Although presence of neurological signs was not associated with T. gondii and N. caninum infections (P = 0.747 and P = 0.21, respectively), there was a statistical association between T. gondii seropositivity and peripheral neurological alteration (P = 0.016) among dogs with neurological signs. Raw meat ingestion was the only risk factor associated with the presence of anti-N. caninum antibodies (P = 0.041). Results revealed evidence of exposure to N. caninum and T. gondii in dogs irrespective of the presence of neurological signs. Moreover, this study highlighted the need for serological investigation of T. gondii in dogs with disturbances in peripheral nervous systems and not offering raw meat to animals to avoid the risk of N. caninum infection.

Este estudo teve como objetivo investigar a associação entre sinais neurológicos, assim como possíveis fatores de risco e soroprevalência de Toxoplasma gondii e Neospora caninum em cães de Campo Grande, região de Mato Grosso do Sul, Brasil. Nesse estudo, os cães foram divididos em dois grupos, baseado na presença ou ausência de sinais neurológicos (n = 30 em cada grupo). O diagnóstico sorológico foi realizado por meio do teste imunofluorescência indireta (RIFI). No grupo com distúrbios neurológicos, 23.3% e 30% dos cães tinham anticorpos anti-T. gondii e anti-N. caninum, respectivamente. Além disso, três cães deste grupo estavam coinfectados com ambos os protozoários. No grupo sem sinais neurológicos, 16.7% e 13.3% dos cães foram soropositivos para T. gondii e N. caninum, respectivamente. Apesar da presença de sinais neurológicos não ter sido associado a infecção por T. gondii ou N. caninum ( P = 0.747 e P = 0.21, respectivamente), houve associação estatística entre soropositividade para T. gondii e alteração neurológica periférica (P = 0.016) entre os cães com sinais neurológicos. A ingestão de carne crua foi o único fator de risco que apresentou associação com a presença de anticorpos para N. caninum (P = 0.041). Estes resultados mostraram evidência de que a exposição a N. caninum e T. gondii em cães independe da presença de sinais neurológicos. Além disso, este estudo destaca a necessidade de investigação sorológica para T. gondii em cães com distúrbios neurológicos periféricos, e o oferecimento de carne crua aos animais deve ser evitada devido ao risco de infecção por neosporose.

Epidemiological evaluation of Neospora caninum in dairy animals

The purpose of the study is to explore the epidemiological information concerning the spread of neosporosis in the Moscow region (Russian Federation) and Almaty region (Republic of Kazakhstan). The study is conducted in 2019 in the Moscow region (Russian Federation) and Almaty region (Republic of Kazakhstan). The study sample includes 800 cows (400 animals at each of the two locations), 100 at each of the 4 cattle farms in the Moscow region and 100 at each of the 4 cattle farms in the Almaty region. There were more seropositive cows on the rest of farms as compared to farm No. 1: 1.9 times more on farm No. 2 (p ≤ 0.01), 2.4 times more on farm No. 3 (p ≤ 0.001), and almost 4 times more on farm No. 4 (p ≤ 0.0001). In terms of the abortion rates, the maximum difference between the farms was 5-fold in the Moscow region (p ≤ 0.0001) and 3-fold in the Almaty region (p ≤ 0.001). Positive correlations exist between all the studied parameters (the proportion of seropositive animals, the proportion of seroprevalent animals, the abortion rate, and the stillbirth rate). The results of the study are mainly extremely valuable for the global economy, because the Republic of Kazakhstan and the Russian Federation occupy an important place in the export of meat and dairy products.(AU)

Neospora caninum-associated abortions in cattle from Southern Brazil: Anatomopathological and molecular characterization.

This study aimed to evaluate the N. caninum associated abortions in cattle in the state of Santa Catarina, in the southern Brazil. Aborted bovine fetuses were necropsied, submitting organ samples for histopathological evaluation. Brain fragments were analyzed by polymerase chain reaction (PCR). The diagnosis of abortion due to N. caninum was established through histopathology and molecular analysis in 53.84% (28/52) of the cases, with PCR detection in 71.42% (20/28). The histopathological evaluation showed lesions in 75% of the cases, characterized by mononuclear necrotizing encephalitis, mononuclear myocarditis, mononuclear myositis, mixed placentitis, and mononuclear pneumonia. Neospora caninum was the primary etiological agent associated with causes of abortion in cattle in the present study.

Prevalence of Neospora caninum, Toxoplasma gondii and Brucella abortus in water buffalo (Bubalus bubalis): Climatic and environmental risk factors in eastern and southeast Mexico.

A total of 600 serum samples from five farms were collected and the geographic coordinates of each farm were georeferenced to establish two Köppen climate classes (wet tropical and tropical rainforest). Serum samples were examined by commercially available enzyme-linked immunosorbent assay (ELISA) kits to detect antibodies against N. caninum and T. gondii, while anti-B. abortus antibodies were analysed using the Rose Bengal test and ELISA kit. The overall estimated prevalence of N. caninum, T. gondii and B. abortus was 41.2%, 30.7% and 0.5%, respectively. The highest percentages of positive buffaloes with neosporosis and toxoplasmosis were found in the states of Tabasco (46.7%, wet tropical climate) and Veracruz (32.7%, tropical rainforest climate), respectively. Multivariate logistic regression showed that N. caninum seropositivity in buffalos was associated with the normalized difference vegetation index (NDVI) (OR: 1.068; 95% CI: 1.026-1.112; P = 0.001) and tropical climate regions (OR: 1.737; 95% CI: 1.112-2.712; P = 0.015). In addition, statistical analysis revealed that sex (OR: 1.737, 95% CI: 1.685-9.737; P = 0.002), NDVI (OR: 1.382; 95% CI: 1.095-1.746; P = 0.007) and rainfall (OR: 1.478; 95% CI: 1.110-1.967; P = 0.007) were significant risk factors for T. gondii infections. These results indicate that the potential impact of the risk factors was different for each disease in buffaloes, which may be useful for developing regionally adapted control strategies and preventive measures.

Association of bovine viral diarrhea virus, bovine herpesvirus 1, and Neospora caninum with late embryonic losses in highly supplemented grazing dairy cows.

The objectives of this study were: 1- to evaluate the association of Bovine Viral Diarrhea Virus (BVDV), Bovine Herpes Virus 1 (BoHV-1), and Neospora caninum (N. caninum) with the risk for Late Embryonic Loss (LEL) in grazing dairy cows, 2- to evaluate blood progesterone concentration at the time of LEL occurrence, and 3- to describe a novel ultrasound-guided technique for conceptus sampling. We run a prospective cohort study involving 92 cows (46 LEL and 46 NLEL). An LEL cow was that having an embryo with no heartbeat, detached membranes, or floating structures, including embryo remnants detected at pregnancy check by ultrasonography (US) 28-42 days post-AI, whereas an NLEL cow was that with embryo heartbeats detectable by US at pregnancy check 28-42 d post-IA. We took two blood samples from every cow at pregnancy check by US (the day of LEL detection) and 28 d later to perform serological diagnosis of BVDV, BoHV-1, and N. caninum; and to measure blood progesterone concentration at pregnancy check (28-42 d post-AI). We also sampled the conceptus from all the LEL cows. We performed PCR to detect BVDV, BoHV-1, and N. caninum in sampled conceptuses from LEL cows. Finally, we evaluated the associations of risk factors (serological titers, seroconversion, and progesterone) with LEL odds with logistic models. The risk for LEL was associated with serological titers to BVDV (P = 0.03) and tended to be associated with seroconversion to BVDV, given that 19.6% (9/46) in LEL and 6.5% (3/46) in NLEL cows seroconverted to BVDV (P = 0.09). In addition, BVDV was detected in conceptuses from LEL cows that seroconverted to BVDV but not in LEL cows that did not seroconvert. Conversely, the risk for LEL was not associated with the titers or seroconversion to BoHV-1 and N. caninum. BoHV-1 and N. caninum were not identified in any of the conceptuses. Finally, blood progesterone concentration was similar in LEL and NLEL cows, and it was not associated with the risk for LEL (P = 0.54). In conclusion, BVDV infection is a risk factor for LEL in dairy cows.