Neospora caninum infection in Iran (2004-2020): A review

Prevalence of Neospora caninum and associated risk factors in semi-intensive female water buffaloes reared in Greece, using an ELISA kit on milk samples

Neospora caninum is an apicomplexan (family: Sarcocystidae) protozoan parasite with a global distribution. In the N. caninum life cycle, dogs and other related canids are the definitive hosts, while other animals such as water buffaloes (Bubalus bubalis) constitute the intermediate host for this parasite. In many countries, the water buffalo is of high economic importance, providing valuable high-quality products for human needs. Although knowledge concerning the prevalence of this parasite in intermediate animal host populations is crucial, data from water buffalo are scarce. Keeping this in mind, the aim of this study was to examine the presence and assess the prevalence rates of N. caninum infection in water buffaloes in Northern Greece, where this animal husbandry sector started to raise, as well as to determine associated risk factors, with the application of a commercially available Neospora ISCOM ELISA test kit, developed for the detection of antibodies against N. caninum in milk samples The study was conducted during January-June 2023 in a total of 172 individual raw milk samples, collected from dairy buffaloes, reared under a semi extensive system, in three different farms. Information on the status of N. caninum infection in buffaloes from Greece was so far unknown with a lack of epidemiological or risk factors associated. For the detection of N. caninum, the commercially available Neospora ISCOM ELISA test kit (SANOVIR ®, Svanova Biotech AB, Uppsala, Sweden) was utilized. Results demonstrated the presence of N. caninum in water buffaloes from Greece for the first time. All positive N. caninum animal were asymptomatic, with absence of any disease signs. The overall prevalence of infection was 22.10%, whereas the main risk factors include the presence of dogs as well as the low biosecurity measures.

Seroprevalence of Toxoplasma gondii and Neospora spp. in horse population of Tehran, Iran

Neospora spp. and Toxoplasma gondii are two closely related protozoan parasites that are widely distributed throughout the world. Horses can act as intermediate hosts for both parasites and can acquire disease. Blood samples were taken from 487 clinically healthy horses from 17 different mechanized stables in Tehran, the capital of Iran, during September and November of 2022. IFAT and ELISA were employed to detect antibodies directed against Neospora spp. and T. gondii. The anti-N. caninum antibodies were detected in 52 of the horses (10.67%) based on IFAT and in 86 of the 487 horses (17.65%) based on the ELISA test. Also, antibodies against T. gondii were detected in 41 horses (8.42%) based on IFAT and in 63 of 487 horses (12.94%) based on the ELISA test. Also, in 6 of the horses (1.23%) based on IFAT and in 13 of the 487 horses (2.67%) based on the ELISA test, double positivity suggested co-infection with both parasites. Gender, age groups, and the presence of dogs for neosporosis, and age groups and the presence of cats for toxoplasmosis, could be considered factors having an influence on the seroprevalences (P < 0.05). The results proved the importance of the urgent implementation of stringent regulatory measures to prevent and control the spread of these parasites.

Seroprevalence and molecular detection of Toxoplasma gondii and Neospora caninum in beef cattle and goats in Hunan province, China

BACKGROUND

Toxoplasma gondii and Neospora caninum are closely related protozoan parasites that are considered important causes of abortion in livestock, causing huge economic losses. Hunan Province ranks 12th in the production of beef and mutton in China. However, limited data are available on the seroprevalence, risk factors and molecular characterization of T. gondii and N. caninum in beef cattle and goats in Hunan province, China.

METHODS

Sera of 985 beef cattle and 1147 goats were examined for the presence of specific antibodies against T. gondii using indirect hemagglutination test (IHAT) and anti-N. caninum IgG using competitive-inhibition enzyme-linked immunoassay assay (cELISA). Statistical analysis of possible risk factors was performed using PASW Statistics. Muscle samples of 160 beef cattle and 160 goats were examined for the presence of T. gondii DNA (B1 gene) and N. caninum DNA (Nc-5 gene) by nested PCR. The B1 gene-positive samples were genotyped at 10 genetic markers using the multilocus nested PCR-RFLP (Mn-PCR-RFLP).

RESULTS

Specific IgG against T. gondii were detected in 8.3% (82/985) and 13.3% (153/1147) and against N. caninum in 2.1% (21/985) and 2.0% (23/1147) of the beef cattle and goats, respectively. Based on statistical analysis, the presence of cats, semi-intensive management mode and gender were identified as significant risk factors for T. gondii infection in beef cattle. Age was a significant risk factor for T. gondii infection in goats (P < 0.05), and age > 3 years was a significant risk factor for N. caninum infection in beef cattle (P < 0.05). PCR positivity for T. gondii was observed in three beef samples (1.9%; 3/160) and seven chevon samples (4.4%; 7/160). Genotyping of PCR positive samples identified one to be ToxoDB#10. The N. caninum DNA was observed in one beef sample (0.6%; 1/160) but was negative in all chevon samples.

CONCLUSIONS

To our knowledge, this is the first large-scale serological and molecular investigation of T. gondii and N. caninum and assessment of related risk factors in beef cattle and goats in Hunan Province, China. The findings provide baseline data for executing prevention and control of these two important parasites in beef cattle and goats in China.

Establishment of an ultrasensitive and visual detection platform for Neospora caninum based-on the RPA-CRISPR/Cas12a system

Neospora caninum is a protozoan parasite that causes neosporosis in cattle, and leads to a high rate of abortion and severe financial losses. Rapid and accurate detection is particularly important for preventing and controlling neosporosis. In our research, a highly effective diagnostic technique based on the RPA-CRISPR/Cas system was created to successfully identify N. caninum against the Nc5 gene, fluorescent reporter system and the lateral flow strip (LFS) biosensor were exploited to display results. The specificity and sensitivity of the PRA-CRISPR/Cas12a assay were evaluated. We discovered that it was highly specific and did not react with any other pathogens. The limit of detection (LOD) for this technology was as low as one parasite per milliliter when employing the fluorescent reporter system, and was approximately ten parasites per milliliter based on the LFS biosensor and under blue or UV light. Meanwhile, the placental tissue samples were detected by our RPA-CRISPR/Cas12a detection platform were completely consistent with that of the nested PCR assay (59.4 %, 19/32). The canine feces were detected by our RPA-CRISPR/Cas12a detection platform were completely consistent with that of the nested PCR assay (8.6 %, 6/70). The RPA-CRISPR/Cas12a detection procedure was successfully finished in within 90 min and offers advantages of high sensitivity and specificity, speed and low cost. The technique was better suitable for extensive neosporosis screening in non-laboratory and resource-constrained locations. This study provided a new strategy for more rapid and portable identification of N. caninum.

Molecular detection and phylogenic characterization of Neospora caninum in naturally infected sheep in Alborz and Qazvin provinces, the north of the central region of Iran

Neospora caninum is a protozoan coccidian parasite that can act as a cause of abortion in sheep. The aim of this study was to investigate the presence of this parasitic agent and its role in causing abortion in sheep of Iran. Between June 2019 and February 2022, 100 samples [brain (n = 39), placenta (n = 8), embryonic membrane (n = 7), cotyledon (n = 7), umbilical cord (n = 2), homogenate mixture of tissues (heart, liver, spleen and digestive track) (n = 37)] that were collected following the necropsies of 39 aborted ovine fetuses from different parts of the Alborz and Qazvin provinces, the north of the central region of Iran were employed for DNA extraction. Nc-5 was selected as the target gene sequence for amplification of DNA by using four pairs of primers in two semi-nested PCR. Samples considered positive for the presence of the NC-5 gene were examined to further confirm the presence of the ITS1 gene. Sequence of NC-5 gene was detected from the 27 tissue samples of 23 aborted ovine fetuses. The ITS1 gene sequence was detected in all of the 27 tissue samples that were positive for the NC-5 gene analysis. Brain tissue was the most studied tissue, and the highest number of positive cases was observed in this tissue. The present study updated the situation of ovine neosporosis in the central region of Iran and confirmed the presence of the N. caninum among sheep flocks' abortion.

Assessment of Neospora caninum infection in bulls using serological and molecular techniques

Neospora caninum is a significant cause of abortion and economic losses in cattle worldwide. The main aim of the present work was to detect the prevalence of N. caninum infection in bulls in Hamedan (Iran) using serology and molecular techniques. All blood samples (n = 792) were screened for detecting the antibodies to N. caninum using enzyme-linked immunosorbent assay (ELISA). Then seropositive animals were rechecked using the immunofluorescent antibody test (IFAT). Also, blood, epididymis, and spinal cord samples were collected from animals for molecular analysis using nested PCR. In serology, using ELISA, 3.91% of animals were seropositive for N. caninum. Additionally, true prevalence based on the sensitivity and specificity of the ELISA was calculated 1.25% (95% CI: 0.48-2.02%). Neospora-infection in animals, calculated as the number of bulls seropositive and/or one sample positive to nested PCR, was 3.40%; and 19 bulls tested positive by both serology and molecular diagnostic methods. The overlaps between ELISA and molecular results were observed in 74.19% of whole blood samples, 80.64% of the epididymis, and 87.09% of the spinal cord. Using ELISA, the seroprevalence of N. caninum was detected 1.8% in ≤2 and 5.45% in >2 years old group of animals (p = 0.009, PR = 3.1). In addition, the seropositivity in Holstein and native breed animals was calculated 6.57% and 2.93%, respectively (p = 0.019, PR = 2.3). Seven sequences with 94.9-99.3% similarity were detected in multiple alignments of positive PCR products. Our work was the first comprehensive evaluation of Neospora-infection/neosporosis in Iranian bulls. We detected a low prevalence of infection in animals compared to previous reports. The ELISA is a sensitive serological technique for detecting the highest number of positive bulls in the present investigation and, the nested PCR is a reliable technique to identify Neospora-DNA.

Seroprevalence of Neospora caninum antibodies in dogs, cows, and humans in Assiut province, Egypt: a pilot study

Neospora caninum is an intracellular coccidian parasite infecting a broad range of hosts globally. Despite the existence of several epidemiological studies on neosporosis, there is a limited knowledge regarding the prevalence of N. caninum infection among dogs, cows, and humans in Egypt. To address this knowledge gap, we conducted an epidemiological investigation in the Assiut province of Egypt to determine the seropositivity of N. caninum infection among cows, dogs, and pregnant women, as well as the associated risk factors. By employing an indirect enzyme linked immunosorbent assay, we found specific N. caninum IgG antibodies in 6% (6 of 100) and 2.33% (1 of 43) of cows and dogs' sera, respectively. However, we are unable to detect antibodies in the 48 tested human sera. Moreover, no statistical significance was observed among the analyzed risk factors associated with seropositive cows and dogs. Our study highlights the presence of N. caninum in cows and dogs in the Assiut province, Egypt. Further, it underscores the need for improved comprehensive surveillance of N. caninum infection in a large population of cattle across various locations to obtain a better understanding of the economic burden associated with the disease.

Graphical abstract

Pathological characteristics and congenital immunological responses of pigeons-infected with Neospora caninum

Pigeons are natural intermediate host of Neospora caninum (N. caninum). In comparison to ruminants, N. caninum causes milder clinical symptoms and less financial loss to pigeons. Natural infectious rates and high prevalence of N. caninum in pigeons, and death cases of N. caninum-infected pigeons under experimental conditions have been reported, but the detailed pathological characteristics and congenital immunological responses of pigeons-infected with N. caninum remain not well described. In this study, pigeons were infected intraperitoneally with 107 N. caninum tachyzoites. N. caninum in tissues was detected by qPCR. Pathological changes of tissues were examined by hematoxylin-eosin staining. Blood smears were prepared for counting eosinophils changes in blood. Heterophil extracellular traps (HETs) in vivo and in vitro were quantified by Pico Green. N. caninum-induced HETs structures were observed by immunofluorescence staining. The model of pigeons-infected with N. caninum was successfully established. Lung and duodenum were the main target organs of pigeons-infected with N. caninum. N. caninum caused hemorrhage, edema and inflammatory cell infiltration in liver, pulmonary congestion and hemorrhage, organizational destruction in lung, and shorter villi or even disappear in duodenum. N. caninum also increased the number of eosinophils in blood of pigeons. Moreover, N. caninum-induced HETs release in the congenital immunological system of pigeons were first demonstrated, and the HETs structures were consisted of DNA as the skeleton and modified with citH3 and elastase. N. caninum-induced HETs release was related with NADPH oxidase, TLR 2 and 4, ERK1/2 and p38 MAPK signaling pathways, and glycolysis. In summary, it is the first report on the detailed pathological characteristics and congenital immunological responses of pigeons-infected with N. caninum, which may provide theoretical basis for the prevention and control of Neosporosis in pigeons.

Seroprevalence and associated risk factors of bovine neosporosis in the Khomas region of Namibia

Neospora caninum is a coccidian parasite that occurs worldwide and is one of the most important causes of abortion, especially in cattle. However, no studies have been performed in Namibia to determine the N. caninum status in livestock. Therefore, this study aimed to determine the seroprevalence of N. caninum in cattle and the associated risk factors in the Khomas region of Namibia. A total of 736 sera were collected from cows in 32 farming establishments. These comprised 698 beef and 38 dairy cattle sera and were tested using a commercial enzyme-linked immunosorbent assay (ELISA) kit. Questionnaires were concurrently administered to determine possible risk factors associated with N. caninum seropositivity. A total of 42 sera were positive (all beef), giving an animal-level seroprevalence rate of 5.7%. Eight of the 32 establishments had at least one positive animal, giving a herd-level seroprevalence of 25%. There was no significant association between seropositivity and the presence of dogs, jackals, history of abortions, farm size, number of cattle or average annual rainfall. The establishments with moderate to high numbers of Feliformia were 9.8 times more likely to be seropositive to N. caninum than those with none to low levels of the former (p = 0.0245). The authors concluded that the seroprevalence level of N. caninum in the Khomas region was relatively low compared with other parts of the world and that the role of Feliformia in the epidemiology of bovine neosporosis needed to be further investigated.Contribution: Serological evidence of bovine neosporosis and the associated risk factors are reported in Namibia for the first time. This study contributes to the scientific body of knowledge on N. caninum in Africa, which is currently limited.

Neospora caninum and Toxoplasma gondii infections in one-humped camels (Camelus dromedarius) in central desert of Iran

The protozoan parasite Neospora caninum infects carnivores as definitive and a wide range of mammals as intermediate hosts. This parasite is regarded as an important cause of abortion in cattle worldwide, causing significant economic losses. Although there is serological evidence of infection in Old World camelids, the significance of N. caninum in these animal species is still poorly understood. The aim of this study was to use molecular and histological methods to detect N. caninum in the blood and tissues of 100 slaughtered one-humped camels (Camelus dromedarius) in Iran. For this, genomic DNA was extracted from blood, brain, portal lymph node and liver of the camels, and nested-PCR assay followed by sequencing were performed. Besides, paraffin-embedded tissue sections were stained with hematoxylin and eosin (H&E) and studied microscopically. In addition, immunohistochemical staining for N. caninum was attempted on brain samples with positive PCR results. All animals were tested for antibodies against N. caninum and Toxoplasma gondii by whole tachyzoite-agglutination tests. N. caninum DNA was detected in blood, brain, and portal lymph node, but not in the liver of two (2%) camels. Histopathological examination revealed cysts resembling N. caninum in brain samples of one of these camels; however, immunohistochemical staining for N. caninum and T. gondii did not allow a morphological identification. IgG antibodies to N. caninum and T. gondii were detected in 36% and 35% of the camels, respectively. This study provides the first insight into direct detection of N. caninum in C. dromedarius in Iran. Further molecular studies on aborted fetuses, stillborn animals and cases of perinatal mortality are needed to understand the possible involvement of N. caninum in cases of reproductive failure. As the definitive hosts of N. caninum are domestic and wild canids, producers should be advised to monitor and limit exposure of their camelids to these species and their feces.

Serological Survey and Risk Factors of Neospora caninum Infection in Dog Population of Qom, Central Iran

The Article Abstract is not available.  

Dead or Alive? A Review of Perinatal Factors That Determine Canine Neonatal Viability

Simple Summary

The article summarizes the current knowledge on factors related to pregnancy, parturition, and newborns that affect the health status of a puppy and determine its chances for survival and development. The detailed information is provided in terms of breed predispositions, objectives of pregnancy monitoring, potential sources of complications, and veterinary advances in care and treatment of perinatal conditions. Successful pregnancy outcomes still pose challenges in veterinary neonatology; thus, publications presenting the current state of knowledge in this field are in demand.

Abstract

The perinatal period has a critical impact on viability of the newborns. The variety of factors that can potentially affect the health of a litter during pregnancy, birth, and the first weeks of life requires proper attention from both the breeder and the veterinarian. The health status of puppies can be influenced by various maternal factors, including breed characteristics, anatomy, quality of nutrition, delivery assistance, neonatal care, and environmental or infectious agents encountered during pregnancy. Regular examinations and pregnancy monitoring are key tools for early detection of signals that can indicate disorders even before clinical signs occur. Early detection significantly increases the chances of puppies’ survival and proper development. The purpose of the review was to summarize and discuss the complex interactions between all elements that, throughout pregnancy and the first days of life, have a tangible impact on the subsequent fate of the offspring. Many of these components continue to pose challenges in veterinary neonatology; thus, publications presenting the current state of knowledge in this field are in demand.

Neospora caninum Infection in Cattle in the Province of Kohgiluyeh and Boyer Ahmad, Southwest of Iran: Seroprevalence and Molecular Assessment

Introduction

Among the protozoa of veterinary importance, Neospora caninum is responsible for large economic and productive losses in cattle herds. Dogs are being considered the definitive hosts of the parasite. Neospora caninum has gained considerable attention through its role in the etiology of bovine abortion. The current study aimed at assessing the status of Neospora infection in cattle in Boyer-Ahmad County in Kohgiluyeh and Boyer-Ahmad province, southwest of Iran.

Methods

In this cross-sectional study, 150 cattle blood samples were collected and samples were screened for N. caninum antibodies using a modified direct agglutination test (MAT). For the same samples, 130 buffy coats were collected and tested, by PCR, for the presence of N. caninum DNA, targeting the Nc-5 gene.

Results

Anti-N. caninum antibodies were detected in the sera of 49 out of 150 cattle which is corresponding to a seroprevalence rate of 32.7%. Neospora DNA was detected in buffy coats of 26 out of 127 (20.47%) cattle. Even though Neospora infection was more common in females and in five-year-old cattle by serology and molecular methods, yet there was no statistically significant difference between age, sex, and Neospora infection in both molecular and serological methods (p > 0.05).

Conclusion

Findings of the current study indicate a high rate of N. caninum infection in cattle of Boyer-Ahmad region in the southwest of Iran. This issue should be further investigated and the prevention and control of this parasite in livestock, due to the high financial burden of this parasite in the livestock industry, should be considered.

Molecular detection and phylogenetic analysis of Neospora caninum in various hosts from Iran

Different N. caninum strains with distinct biological characteristics and pathogenicity have been introduced from various areas of the world. This study aimed to detect Neospora-infection in different hosts from Iran using the nested-Polymerase Chain Reaction (PCR) technique and to perform the phylogenetic analysis of N. caninum isolates using the Nc-5 gene. Different species of parasite hosts (cattle, dogs, rodents, cats, and birds) from the dairy farms with history of abortion with intensive breeding systems in Hamedan Province, Iran were included for sampling. The stillbirth fetuses of cattle, sheep, and goats were also collected from the slaughterhouse. The nested-PCR technique was used to identify the Neospora-DNA in the aborted fetal materials. The PCR products of the positive samples were sequenced and compared with other isolates in GenBank. Antibodies to N. caninum was found in 19.1% of dogs. Also, 11.4% of dogs were positive for Neospora-like oocysts using microscopy method. The molecular prevalence of N. caninum was 10.6% in dogs, 13.6% in cattle, 35.4% in the aborted fetuses of cows, 31.9% in rodents, 7.6% in pigeons, 1.9% in sparrows, 5.1% in cats, and 7% in the semen sample of bulls. A sampled coyote was positive while the stillbirth fetuses of sheep and goats were negative. The multiple sequence alignments indicated that 34 sequences of N. caninum bore a 94.9-99.3% similarity to each other. Hence, these sequences were classified into two major clusters (clusters A and B) and seven sub-groups (isolates 1-7). The sequence of coyote had a high similarity to the sequences derived from dogs and cows. Also, root diagram showed the isolates of current study and previous reported from Iran have a similar origin. This study provided a phylogenetic analysis of Neospora-infection in different hosts, and for the first time, explored Neospora-infection in coyotes from Iran. Different isolates were detected in the studied population in the region. Comparison of the sequences showed the farm dogs play an important role in the life cycle and distribution of the parasite; so the relationship of dogs with the herd and their access to aborted materials should be restricted. Also, regular control of rodents' population and culling of seropositive cows with a history of abortion is essential for cutting the chain of transmission.

Serological Survey on the Occurrence of Rickettsia spp., Neospora caninum, Bartonella henselae and Toxoplasma gondii in Cats from Tuscany (Central Italy)

Simple Summary

Domestic and stray cats are frequently infected by pathogens, some of which are zoonotic. The occurrence of microorganisms such as Bartonella henselae and Toxoplasma gondii, even though they are well known, could be underestimated because they are not regularly investigated in cats. Other pathogens, such as Neospora caninum and Rickettsia spp., have not been largely studied in feline populations and data about their spreading in Italian cats are very scanty. Monitoring of domestic and stray cats for these pathogens is important to evaluate the health status of the animals, but also, regarding B. henselae, Rickettsia spp. and T. gondii, from a One Health perspective.

Abstract

Asymptomatic cats often harbor pathogens, some of which have not been largely investigated in feline populations. The aim of this study was to evaluate the occurrence of antibodies against Rickettsia conorii, Rickettsia felis, Rickettsia typhi, Neospora caninum, Bartonella henselae and Toxoplasma gondii in cats from Tuscany. Ninety-five blood serum samples, previously collected, were analyzed by indirect immunofluorescence assay. Fifty-six (58.94%) cats had antibodies to at least one investigated pathogen: 28 (29.47%) cats were positive for B. henselae, 17 (17.89%) for R. felis, 14 (14.73%) for R. conorii, 14 (14.73%) for T. gondii, 2 (2.1%) for N. caninum. No cats were positive for R. typhi. Positive reactions to two or more pathogens were detected in 18 (18.94%) cats. The occurrence of antibodies against these microorganisms suggests that cats, even though asymptomatic, may be infected by pathogens, often zoonotic, and thus may be a source of infections for other animals and humans.