Molecular detection and characterization of Anaplasma ovis, Theileria ovis, and Theileria lestoquardi in sheep and goats in Luxor, Egypt

BACKGROUND

Tick-borne diseases cause economically significant losses to animal production globally, and anaplasmosis and theileriosis are associated with the greatest losses. However, the spread of the relevant pathogens in flocks of domesticated animals in southern Egypt is little understood. Accordingly, in this study, we aimed to determine the prevalences of Anaplasma ovis, Theileria ovis, and Theileria lestoquardi in southern Egyptian sheep and goats through blood tests, and to make a molecular characterization of the A. ovis detected in sheep targeting a specific gene.

RESULTS

We collected blood samples collected from 300 sheep and goats (n=150 /species) in Luxor Province in southern Egypt, and analyzed them for the presence of A. ovis, T. ovis and T. lestoquardi with screening by conventional and nested PCR targeting the msp4 and msp5, 18S rRNA, and merozoite surface protein genes. For A. ovis 140/300 samples (46.66%) were positive overall, with 90/150 (60%) and 50/150 (33.33%) positive samples in sheep and goats, respectively. Two major surface protein genes of A. ovis, msp4 and msp5, were sequenced using DNA extracted from sheep and goat blood samples, for phylogenetic analysis and genotyping. The msp4 gene sequence revealed no significant genetic diversity, to contrast to data on A. ovis strains from other countries. For T. lestoquardi, 8/150 (5.33%) samples were positive in sheep, but no samples were positive in goats (0%). For T. ovis, 32/150 (21.33%) samples were positive in sheep, but no samples were positive in goats (0%). Sequencing targeting the merozoite surface protein gene for T. lestoquardi and the small subunit ribosomal RNA gene for T. ovis revealed no significant genetic diversity in the study, another contrast to data on A. ovis strains from other countries.

CONCLUSION

This study provides valuable data on phylogenetic and molecular classifications of A. ovis, T. ovis and T. lestoquardi found in southern Egyptian sheep and goats. It also represents the first report on detection and molecular characterization of T. lestoquardi in southern Egyptian sheep based on the specific merozoite surface protein gene, thus providing valuable data for molecular characterization of this pathogen in southern Egypt.

Serosurvey and associated risk factors for Chlamydia abortus infection in Dromedary camels in Egypt

Chlamydia abortus (C. abortus) is a gram-negative, obligate intracellular bacterium that causes major public health problems in human and reproductive problems in animals. The information about the epidemiology of this pathogen among camels in Egypt is very rare. This study aimed to evaluate the existence of antibodies against C. abortus in camels and assess the related risk factors for infection. A total of 410 blood samples were collected from camels from three Egyptian governorates and examined using commercial ELISA kit. The overall seroprevalence rate was 6.6% and the higher C. abortus seropositivity rate was found in Giza governorate. Location, sex and infestation by ectoparasites did not influence on the seroprevalence of the disease. In addition, age, herd size, contact with small ruminants and history of abortion were identified as risk factors for C. abortus infection according to the univariate analysis. Based on multivariate analysis, age group of 4-8 years, small herd size, contact of camels with sheep and goats, and history of abortion were found to be significant risk factors for chlamydiosis transmission in camels. These factors had odds ratios of 4.23, 3.51, 2.84, and 2.5, respectively. These results suggest that camels have a role in the epidemiology of C. abortus infection. This promotes awareness and severe public health concern about infectious camel illnesses, allowing for additional diagnostic advancements and effective management techniques to be developed.

Prevalence and potential risk factors for Cryptosporidium spp. infection in horses from Egypt

Cryptosporidium is an intestinal protozoan that cause diarrhea in livestock all over the world and have zoonotic importance. The present study aimed to determine the prevalence of Cryptosporidium spp. in horses in Egypt and evaluate the associated risk factors. A total of 420 fecal samples were collected from three governorates (Giza, Kafr ElSheikh and Qalyubia) and examined microscopically using Ziehl-Neelsen staining method. The overall prevalence of Cryptosporidium spp. was 29% and Kafr ElSheikh governorate had the highest rate in comparison to other areas. The prevalence of Cryptosporidium spp. in examined horses had significant association with sex, age, type of management, absence of bedding and presence of dogs. The higher prevalence rate was observed in females (32.2%), age group less than two years (43.2%), mixed (grazing and stable) horses (36.1%), animals had history of diarrhea (33%), absence of bedding (35.1%) and contact with dogs (35.7%). These findings give baseline data for further research. It is necessary to establish control strategy for Cryptosporidium spp. infection in order to lower the risk of infection in animals and human.

Serosurvey and associated risk factors for Neospora caninum infection in Egyptian water buffaloes (Bubalus bubalis)

Neosporosis is a parasitic disease that causes reproductive disorders in animals, making it a barrier to maximum efficiency. The purpose of this study was to determine the seroprevalence of Neospora caninum (N. caninum) antibodies in water buffaloes from four governorates in northern Egypt. A commercial indirect-ELISA test was used to detect antibodies against N. caninum in the serum of 450 water buffaloes. The total seroprevalence of N. caninum in water buffaloes from Egypt was 31.3%, and the highest prevalence was observed in Gharbia governorate. The identified risk factors for N. caninum infections in water buffaloes were sex (OR = 1.96, 95%CI: 1.22-4.17), buffaloes more than 4 years of age ( OR = 5.80, 95%CI: 2.26-14.86), abortion in second trimester (OR = 16.48, 95%%CI: 2.99-34.03), history of abortion (OR = 3.45, 95%CI: 1.58-7.52) and contact with dogs (OR = 2.55, 95%CI: 1.51-4.32). Thus, more studies are needed to determine the role of buffaloes in the epidemiology of neosporosis in Egypt.

Seroprevalence and risk factors for Neospora spp. infection in equine in Egypt

Neospora infections in equine are associated with reproductive disorders and neurological diseases. Nevertheless, Egypt has no epidemiological information on this parasite in equine. This study determined the prevalence of Neospora spp. infection in 325 equines from three Egyptian governorates located at Northern Egypt using cELISA. The prevalence of antibodies against Neospora spp. was 19% (95% CI: 14.09-25.05) in horse, 34.1% (95%CI: 24.92-44.69) in donkey and 26.7% (95% CI: 15.97-41.04) in mule. In comparison to horse, donkey had a considerably higher chance of contracting Neospora spp. infection (OR = 1.80, 95% CI: 0.78-4.13; P = 0.016). The risk was also higher in freely grazing animals (OR = 3.49, 95% CI: 0.95-12.78; P = 0.059). Moreover, yearling animals (12-24 months) (OR = 5.03, 95% CI: 1.51-16.80; P = 0.009) and those with natural breeding (OR = 11.80, 95% CI: 3.24-42.99, P < 0.0001) and a history of early abortion (OR = 7.04, 95% CI: 3.01-16.47; P < 0.0001) also showed a greater risk of seropositivity. The risk of Neospora infection increased significantly in equines contacted with dogs (OR = 5.16, 95% CI: 1.76-15.10; P = 0.003). This the first serological study to determine the seroprevalence of Neospora spp. in equine in Egypt. Further studies are necessary to identify the species of Neospora and to understand the role of above-mentioned risk factors in spreading of infection.

Fasciola hepatica Infection in Horses in Three Governorates in Northern Egypt: Prevalence and Risk Factors

Fasciola hepatica is a trematode parasite that affects wide range of mammalian hosts including horses. There are no epidemiological data on fasciolosis in Egyptian horses. Hence, the present study aimed to evaluate the seroprevalence of F. hepatica in horses using ELISA as well as assess the associated risk factors for fasciolosis infection. A total of 400 sera samples of horses from three Egyptian governorates were examined. The overall seroprevalence rate in horses was 13% and the disease was more prevalent in Qalubia (14.17%) and Gharbia (16.67%) which are located at Nile Delta. The likelihood of having F. hepatica seropositivity was higher in mixed-breed animals and stallions (OR = 3.97, 95%CI: 1.10-14.28 and OR = 2.07, 95%CI: 1.09-3.93, respectively), and in older horses more than 10 years (OR = 5.69, 95% CI: 1.98-16.36). Horses were more likely to be seropositive with F. hepatica when kept in outdoor housing (OR= 1.53, 95%CI: 0.78-3), during autumn (OR = 3.80, 95%CI: 1.17-12.32) and in the presence of snails (OR = 2.72, 95%CI: 1.34-5.52). Therefore, the obtained data contributes to the understanding of the epidemiology of Fasciola species, assess in establishment of management programmes to reduce disease and public health risks.

Prevalence of Cryptosporidium infection and associated risk factors in calves in Egypt

Cryptosporidium is one of the causative parasitic agents that causes gastrointestinal diseases in calves. The parasite poses a zoonotic risk to immunocompromised individuals and children. Thus, this study aimed to determine the prevalence of Cryptosporidium infection in calves in three Egyptian governorates situated in Nile Delta and assess the associated risk factors. The Cryptosporidium oocysts were detected in 81 out of 430 calves (18.84%). In addition, the univariant analysis showed that age, feeding source, hygienic status, presence of diarrhea and contact with other animals were significantly (P < 0.05) associated with Cryptosporidium prevalence in calves. Furthermore, the risk factors related with Cryptosporidium prevalence were age (OR 1.96, 95%CI 0.97-3.94), feeding on milk and pasture (OR 2.07, 95%CI 1.15-3.72), poor hygienic condition (OR 2.25, 95%CI 1.28-3.94), presence of diarrhea (OR 2.47, 95%CI 1.23-4.96) and contact with other domestic animals (OR 2.08, 95%CI 1.24-3.50). In addition, the PCR assay targeting 18srRNA showed that the most prevalent species among calves was C. parvum. Although additional researches are required to understand the most effective steps that farmers and veterinary professionals should take to decrease the occurrence of Cryptosporidium infection.

Seroprevalence and associated risk factors for Toxoplasma gondii in water buffaloes (Bubalus bubalis) in Egypt

Toxoplasmosis is a parasitic disease caused by Toxoplasma gondii and affecting all warm-blooded animals. The available data about the epidemiological situation of T. gondii in water buffaloes in Egypt are scarce. Thus, a cross-sectional study was conducted to determine the seroprevalence of T. gondii in water buffaloes in three Egyptian governorates and to evaluate the associated risk factors for the infection. A total of 430 sera samples were examined using commercial Indirect ELISA Multi-species kit. The overall seroprevalence rate of T. gondii in examined water buffaloes was 7.4 %, and the highest rate (9.3 %) was found in Kafr ElSheikh governorate. Multivariate logistic regression analysis showed that adult buffalo (OR = 7.10; 95 % CI: 0.87-57.68; P = 0.067) and small herds (OR = 8.42; 95 % CI: 1.07-66.02; P = 0.043) were more likely than young buffalo and large herds to become infected with T. gondii. Moreover, the risk of buffaloes contracting T. gondii infection was higher in winter and especially among animals contacted with cats. It is necessary to identify risk factors in order to determine what mitigation, control, and prevention strategies to implement in order to reduce, control, and prevent T. gondii infection in domestic animals, which will in turn reduce human infection with the disease.

Toxoplasma gondii infection in Egyptian domestic sheep and goats: seroprevalence and risk factors

Toxoplasma gondii is an apicomplexan protozoan parasite that has been associated with reproductive failure in small ruminants. Although T. gondii infections in ruminants and humans have been recorded in several Egypt's governorates, but little is known about the risk factors associated with T. gondii infections. In this study, 350 sheep and 290 goat serum samples from three governorates in Egypt were examined for presence of antibodies against T. gondii, and evaluate the associate risk factors for the infection. The seroprevalence in sheep and goats was 24% and 38.28%, respectively. In sheep and goats, age, sex, the presence of cats, and hygienic conditions were identified as risk factors for T. gondii infection. In addition, the prevalence rates were significantly higher in older animals more than 2 years old, females, among animals contacted with cats, and animals living in bad hygienic condition. In conclusion, sheep and goats in the examined regions are commonly infected with T. gondii. The identification of risk variables defines the sort of actions to be implemented in order to decrease, and prevent T. gondii infection in small ruminant animals and, as a result, human infection.

Serosurvey and associated risk factors for Chlamydia abortus infection in cattle from Egypt

Chlamydia abortus is an important gram-negative pathogen poses serious public health problem in human and reproductive disorders in animals. There are very few data on the prevalence of C. abortus in cattle and none on the associated risk factors for infection in cattle in earlier literature. Therefore, the objective of the current study was to evaluate the risk factors and seropositivity of C. abortus infection in cattle. In northern Egypt, 400 cattle from five governorates were examined using indirect enzyme-linked immunosorbent assay (ELISA) in a cross-sectional study. The results revealed that the overall prevalence for C. abortus in cattle was 20.75 % and the highest level was observed in Gharbia 26.67 % while the lowest rate was found in Menofia governorate 15.38 %. The age, herd size, application of disinfection and history of abortion or stillbirth had significant association with prevalence of C. abortus infection by univariate analysis. In addition, Cattle above the age of 4 years, a median herd size of 10-50, the absence of disinfectant application, a history of stillbirth, and a history of abortion were all found as risk factors for C. abortus infection using multivariable logistic regression. These findings could be used to establish effective management strategies to prevent and control C. abortus infection in cattle and lower the risk of C. abortus infection in cattle in Egypt.

Molecular Detection and Associated Risk Factors of Brucella melitensis in Aborted Sheep and Goats in Duhok Province, Iraq

Brucellosis in sheep and goats has a significant economic and zoonotic impact on the livestock population of Duhok province, Iraq. A total of 681 blood samples from aborted sheep and goats were collected from different flocks in seven districts of Duhok and tested using real-time polymerase chain reaction (RT-PCR). Logistic regression was used for the analysis of the potential risk factors associated with RT-PCR positivity. Results revealed an overall prevalence of 35.45% (CI = 2.57) and 23.8% 18 (CI = 0.44) in sheep and goats, respectively. A statistically significant (p = 0.004) difference in prevalence was found between the two species. RT-PCR detected more positive cases in older-aged animals (OR = 0.7164; p = 0.073). A significant difference was found in RT-PCR positivity in relation to different risk factors, including body condition, treatment taken, and abortion frequency (<0.001). The phylogenetic tree based on the 16S rRNA gene indicated that the isolates belonged to B. melitensis and shared a common ancestor and were genetically related to the United States of America (USA), Greece, China, and Nigeria. This study demonstrates that brucellosis is widely prevalent in the study regions. Therefore, the study suggests the implementation of preventive control measures for brucellosis.

Coxiella burnetii and its risk factors in cattle in Egypt: a seroepidemiological survey

Animal production is greatly affected by Q fever. As a result of a lack of methodology and financial means to perform extensive epidemiological surveys, the disease's underdiagnosis has proven to be a challenge for effective control. The present study aimed to determine the seroprevalence of C. burnetii in cattle raising in four governorates situated at Nile Delta of Egypt and assess the associated risk factors for infection. A total of 480 serum samples were collected from cattle and examined for presence of anti-C. burnetii antibodies using indirect ELISA assay. The overall seroprevalence of C. burnetii among examined cattle was 19.8%, with the Qalyubia governorate having the highest prevalence. The results of multivariable logistic regression analysis revealed significant association between C. burnetii seropositivity and age, communal grazing and/or watering, contact with small ruminants and history of infertility. According to the findings of this work, C. burnetii is circulating among cattle living in Nile Delta. It is suggested that adequate hygiene procedures and biosecurity measures should be implemented to limit the transmission of pathogens within cow herds and potential human exposure.

Sero-survey of bovine herpes virus-1 in dromedary camels and associated risk factors

Infectious bovine rhinotracheitis (IBR) is a major animal health hazard in many countries throughout the world, caused by bovine herpesvirus-1 (BoHV-1). The study's goal was to evaluate the prevalence of BoHV-1 seropositivity among dromedary camels in three governorates in northern Egypt, as well as to identify risk variables related with BoHV-1 seropositivity. A total of 321 blood samples were collected randomly from dromedary camels living in the selected governorates and examined for presence of BoHV-1 antibody using ELISA test. The overall seroprevalence of BoHV-1 among examined camels was 5.92% (95%CI: 3.82-9.06). Univariable analysis confirmed that the significant association (P < 0.05) between sex, history of abortion, contact with small ruminants and herd size and BoHV-1 seropositivity. Using multiple logistic regression analysis, the following risk factors were identified to be related with the presence of BoHV-1 infection: sex (OR = 2.54, 95%CI: 0.63-10.22), history of abortion (OR = 4.16, 95%CI: 1.30-13.27), contact with small ruminants (OR = 5.61, 95%CI: 1.67-18.80) and large herd size (OR = 10.52, 95%CI: 2.46-44.91). This study estimated the disease's seroprevalence in Egyptian dromedary camels, implying that camels could act as a BoHV-1 reservoir for transmission to other species.

A survey of bluetongue infection in one-humped camels (Camelus Dromedarius); seroprevalence and risk factors analysis

Bluetongue (BT) is an insect-borne, non-contagious viral disease which affects domestic ruminants including camels and is transmitted by Culicoides spp. Clinical symptoms of BT are typically seen in sheep, although subclinical BT infections are mostly seen in cattle, goats, and camelids. The goal of the present study was to evaluate the sero-prevalence of Bluetongue virus (BTV) in camels from some governorates in Egypt's southern and northern regions, as well as the infection's potential risk factors. During 2020-2021, a cross sectional study was conducted to screen presence of anti-BTV antibodies in 400 serum samples, which were collected randomly from camels, examined using competitive enzyme-linked immunosorbent assay (cELISA). The sera of 102 out of 400 camels tested positive for BTV, representing a frequency of 25.5%. Moreover, the odds of sero-positivity were higher among camels living in Aswan (OR = 5.33, 95%CI: 2.35-12.11), especially in females (OR = 2.63, 95%CI = 1.44-4.09) during summer season (OR = 2.40, 95%CI = 1.20-4.81). Furthermore, the probability of getting BTV infection increased when camels were exposed to the insect vectors (OR = 1.63, 95%CI = 0.87-3.09). The high prevalence of BTV in camels in several Egyptian regions highlights the need for more epidemiological investigations of BTV infection in other ruminant species in order to better control BT disease in these regions.

Molecular epidemiological survey, genetic characterization and phylogenetic analysis of Anaplasma ovis infecting sheep in Northern Egypt

Anaplasma ovis is the most common etiologic agent of ovine anaplasmosis, mainly transmitted by ticks. The present study aimed to determine the molecular prevalence of A. ovis in sheep from Egypt and assessed the associated risk factors. The study was conducted, between January and December 2020, in four governorates situated in Northern Egypt. Blood samples from 355 asymptomatic sheep were collected and examined by the use of PCR specific to A. ovis. Diversity analysis and phylogenetic study based on partial msp4 gene sequence were performed on revealed A. ovis DNA. Overall, the molecular prevalence rate of A. ovis was 15.5% and the highest rate was observed in Kafr ElSheikh governorate (16.8%). Statistical analysis revealed that A. ovis infection was significantly related to sheep gender and to tick infestation. The risk factors that were found to be associated with A. ovis infection in exposed sheep were: female sex (OR=2.6, 95%CI: 1.13-6.12), and infestation with ticks (OR=2.1, 95%CI: 1.11-3.79). The analysis of A. ovis msp4 sequences revealed two different genotypes classified in the Old World sub-cluster with other Egyptian isolates. Investigation on prevalence, risk factors and genetic variability of A. ovis in sheep reported in this study is important for the implementation of control programs. Further studies are needed to determine the vectors and reservoirs of A. ovis in Egyptian small ruminants and to identify the real economic impact of A. ovis infection on the country.

Molecular characterization and phylogenetic analysis of lumpy skin disease in Egypt

Lumpy skin disease (LSD) is an infectious viral disease affecting cattle, cause severe economic losses. In the last few years, the disease is widely distributed in many countries in the Middle East, including Egypt. This study aimed to determine the genetic character of LSDV circulating in some governorates in Egypt and its relation with other LSDVs and vaccine strains in GenBank. A total of 50 skin nodules and 50 blood samples were collected from clinically affected cattle to detect LSDV using PCR targeting the P32 gene. The positive samples were characterized using PCR targeting the GPCR gene. The amplified products of four samples detected in the skin nodule of cattle from Alexandria and Kafr ElSheikh governorates were sequenced, and the phylogenetic tree was constructed. Out of 100 analyzed samples, 70 samples were positive for LSDV by PCR assay. In addition, the sequence alignment of the obtained LSDV strains detected in the Alexandria governorate showed high similarity to the LSDV genome (MN995838). In contrast, LSDV strains from Kafr ElSheikh governorate revealed high similarity and the previous Egyptian strain (MG970343), which was isolated from cattle in Sharkia governorate in 2016. Also, the phylogenetic analysis confirmed that one of the LSDV strain (LC601598) from Alexandria is closely related to the LSDV of Menofia/Egypt/2019 (MN271722), while another one (LC601597) is closely related to vaccine strains of LSDV. Moreover, the LSDV strains from Kafr Elsheikh showed closely related to previous LSDV strains isolated from Menofia (MG970343) and Dakahlia (KP071936) governorates and clustered with other LSDV strains in a distinct cluster. This information is for understanding the epidemiology of LSDV and supporting the establishment of an efficient control program for the disease.

A recent update about seroprevalence of ovine neosporosis in Northern Egypt and its associated risk factors

Neospora caninum (Family: Sarcocystidae) is an obligate intracellular protozoan. It is one of the most critical abortifacients in ruminants. The seroprevalence of antibodies against N. caninum and its risk factors was investigated among 430 sheep from four North Egyptian governorates, Alexandria, Gharbia, Menofia, and Qalyubia, during the period from 2017 to 2018. Generally, the overall prevalence rate of N. caninum among sheep was 8.6%. The logistic regression analysis for the obtained data revealed that N. caninum increased significantly with age (OR = 2.4, 95% CI: 8.4-18.7) of the ewe (OR = 3.3, 95% CI: 7.6-14.9), particularly among sheep in contact with dogs (OR = 4.9, 95% CI: 7.5-14.3). Besides, locality, season, and pregnancy status of examined sheep had no significant effect on the appearance of N. caninum infection. the present findings confirm the presence of N. caninum among sheep in Egypt which probably play a role in reproductive failure in sheep. Therefore, sanitary measures and monitoring of the infection should be implemented to reduce the spreading of the infection.

Seroprevalence and molecular characterization of Brucella species in naturally infected cattle and sheep

Brucellosis is one of the most economically significant infectious diseases in Egypt. The study aimed to assess the seroprevalence by indirect ELISA by examining serum samples from 720 cattle and 320 sheep and detection and characterization of Brucella spp. from 24 clinical samples (placenta) by bacterial culture (BC) and PCR targeting bcsp31 gene. The seroprevalence was 16.7% and 16.25% in cattle and sheep, respectively. There was a significant association (P < 0.05) between the seroprevalence of brucellosis and sex at the level of cattle and age at the sheep level, where seroprevalence was 18.7% in female cattle and 22% in sheep > 2 years. Likewise, seroprevalence was significantly (P < 0.05) different among locations for cattle. Of the 24 clinical samples tested by BC, B. abortus was isolated and identified in 100% of clinical samples. Using PCR, all Brucella strains were positive (100%) regarding bcsp31gene. Nucleotide analyses of seven bcsp31 sequences of the identified strains revealed 99.3-100% identity, with one nucleotide divergence. These results provide an insight into the brucellosis, particularly with the detection of B. abortus from sheep, therefore, further wide epidemiological studies are needed to develop appropriate prevention and control strategies.

A probe-based real-time PCR assay for the detection of Neospora caninum in clinical samples from cattle

Neospora caninum is an apicomplexan protozoan parasite that is a leading cause of abortion in cattle. Detection of parasite-specific DNA by PCR is a highly sensitive method for identifying the presence of N. caninum in a variety of tissues. We developed and validated a probe-based real-time PCR assay targeting the conserved Nc5 gene of N. caninum. Using N. caninum strain Nc-1 genomic DNA and a synthetic gene fragment as amplification standards, we determined the PCR amplification efficiency and the limit of detection to be 95.60% and 3 copies, respectively. Five pathogens frequently associated with bovine abortions, namely bovine viral diarrhea virus types I and II, bovine alphaherpesvirus-1, Chlamydia, and Leptospira, were tested to ensure analytical exclusivity. A total of 103 clinical samples from aborted fetuses were tested concurrently with a standard conventional PCR and the new probe-based real-time PCR assay. All tested samples showed 100% agreement between these two assays. In conclusion, the probe-based real-time PCR assay facilitates accurate and rapid detection of N. caninum from abortions in cattle.

A multi-screening Fast qPCR approach to the identification of abortive agents in ruminants

Abortion in ruminants represents an important economic concern for farmers. Microbial agents, such as Brucella spp., Chlamydia spp., Coxiella burnetii, Leptospira spp., Neospora caninum, Salmonella spp. and Toxoplasma gondii, are among the main infectious causes of abortion and require rapid and reliable diagnosis. This study describes the development of a multi-screening assay using Fast Real-Time PCR (Fast qPCR) that allows, in a single test, the simultaneous identification of the above-mentioned abortive agents. This multi-screening approach is characterized by a mean diagnostic sensitivity and specificity of 100% and 97%, respectively; it has a limit of detection (LOD) ranging from 5 × 10³ to 4 × 10⁴ genomic copies/g of tissue and a very good concordance with traditional end-point PCR assays used in routine diagnostic activity. The proposed method represents a rapid approach to the simultaneous detection of the main abortive agents in ruminants that allows to make an accurate diagnosis and to set up appropriate control measures in a short period of time.

Development of a loop-mediated isothermal amplification technique and comparison with quantitative real-time PCR for the rapid visual detection of canine neosporosis

Background

Dogs are the definitive hosts of Neospora caninum and play an important role in the transmission of the parasite. Despite the high sensitivity of existing molecular tools such as quantitative real-time PCR (qPCR), these techniques are not suitable for use in many countries because of equipment costs and difficulties in implementing them for field diagnostics. Therefore, we developed a simplified technique, loop-mediated isothermal amplification (LAMP), for the rapid visual detection of N. caninum.

Methods

LAMP specificity was evaluated using a panel containing DNA from a range of different organisms. Sensitivity was evaluated by preparing 10-fold serial dilutions of N. caninum tachyzoites and comparing the results with those obtained using qPCR. Assessment of the LAMP results was determined by recognition of a colour change after amplification. The usefulness of the LAMP assay in the field was tested on 396 blood and 115 faecal samples from dogs, and one placenta from a heifer collected in Lopburi, Nakhon Pathom, Sa Kaeo, and Ratchaburi provinces, Thailand.

Results

Specificity of the LAMP technique was shown by its inability to amplify DNA from non-target pathogens or healthy dogs. The detection limit was the equivalent of one genome for both LAMP and qPCR. LAMP and qPCR detected positive N. caninum infection in 15 of 396 (3.8%) blood samples; LAMP detected 9/115 (7.8%) positive faecal samples, while qPCR detected 5/115 (4.3%) positive faecal samples. The placental tissue was shown to be positive by both techniques. Agreement between LAMP and qPCR was perfect in blood samples (kappa value, 1.00) and substantial in faecal samples (kappa value, 0.697).

Conclusions

This is the first known LAMP assay developed for the amplification of N. caninum. The technique effectively and rapidly detected the parasite with high sensitivity and specificity and was cost-effective. This assay could be used in the field to confirm the diagnosis of canine or bovine neosporosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-017-2330-2) contains supplementary material, which is available to authorized users.

Significance and integration of molecular diagnostics in the framework of veterinary practice

The field of molecular diagnostics in veterinary practice is rapidly evolving. An array of molecular techniques of different complexity is available to facilitate the fast and specific diagnosis of animal diseases. The choice for the adequate technique is dependent on the mission and attributions of the laboratory and requires both a knowledge of the molecular biology basis and of its limitations. The ability to quickly detect pathogens and their characteristics would allow for precise decision-making and target measures such as prophylaxis, appropriate therapy, and biosafety plans to control disease outbreaks. In practice, taking benefit of the huge amount of data that can be obtained using molecular techniques highlights the need of collaboration between veterinarians in the laboratory and practitioners.

Nonculture Molecular Techniques for Diagnosis of Bacterial Disease in Animals

The past decade has seen remarkable technical advances in infectious disease diagnosis, and the pace of innovation is likely to continue. Many of these techniques are well suited to pathogen identification directly from pathologic or clinical samples, which is the focus of this review. Polymerase chain reaction (PCR) and gene sequencing are now routinely performed on frozen or fixed tissues for diagnosis of bacterial infections of animals. These assays are most useful for pathogens that are difficult to culture or identify phenotypically, when propagation poses a biosafety hazard, or when suitable fresh tissue is not available. Multiplex PCR assays, DNA microarrays, in situ hybridization, massive parallel DNA sequencing, microbiome profiling, molecular typing of pathogens, identification of antimicrobial resistance genes, and mass spectrometry are additional emerging technologies for the diagnosis of bacterial infections from pathologic and clinical samples in animals. These technical advances come, however, with 2 caveats. First, in the age of molecular diagnosis, quality control has become more important than ever to identify and control for the presence of inhibitors, cross-contamination, inadequate templates from diagnostic specimens, and other causes of erroneous microbial identifications. Second, the attraction of these technologic advances can obscure the reality that medical diagnoses cannot be made on the basis of molecular testing alone but instead through integrated consideration of clinical, pathologic, and laboratory findings. Proper validation of the method is required. It is critical that veterinary diagnosticians understand not only the value but also the limitations of these technical advances for routine diagnosis of infectious disease.