Characteristics and Epidemiological Investigation of Paratuberculosis in Dairy Cattle in Tai'an, China

Accuracy of real-time PCR for the detection of paratuberculosis in actual samples: A systematic review and meta-analysis

Paratuberculosis, an infectious and chronic ailment that affects ruminants, causes significant annual economic losses to the livestock industry. Early diagnosis and prompt culling are the primary measures for controlling this disease, highlighting the need for accurate and rapid diagnostic methods. This systematic review and meta-analysis aimed to evaluate the efficacy of quantitative PCR (qPCR) in the diagnosis of paratuberculosis. We searched for and selected articles from databases including PubMed, Web of Science, Elsevier ScienceDirect, Wiley-Blackwell, Springerlink, AGRICOLA, and CAB Abstracts, with VETQUADAS (VQ) employed to assess the quality of the literature. Meta-analysis and heterogeneity investigation were conducted using the "Meta4diag" package in "R" software, Meta-Disc 2.0, and Meta-Disc, while the Deeks' test was utilized to detect publication bias. The studies included in the systematic review displayed a moderate level of heterogeneity (I² = 48.6 %) with no significant publication bias (p = 0.998). The pooled sensitivity was determined to be 0.92 [95 % confidence interval [CI], 0.85-0.96], and the specificity was 0.85 [95 % CI, 0.77-0.91], with a summary receiver operating characteristic area under the curve (SROCAUC) of 0.95 [95 % CI, 0.91-0.98]. These findings indicate that the qPCR method has high diagnostic value for identifying paratuberculosis in animals. Subgroup analysis revealed satisfactory stability in these studies; however, the current single-target qPCR detection strategy still has limitations, as it fails to simultaneously ensure both sensitivity and specificity. Future developments should focus on multi-target detection strategies to provide more reliable qPCR testing methods for controlling paratuberculosis.

The Analysis of Paratuberculosis Prevalence and Associated Performance Parameters in Dairy Cows from Xi'an City

The aim of this study was to understand the status of Mycobacterium paratuberculosis infection in a large-scale dairy farm in Xi'an city and evaluate the impact via a "quarantine + elimination" model of bovine paratuberculosis on the production performance, reproductive performance, and economic benefits in said dairy farm. The paratuberculosis antibodies from 4488 dairy cow sera were detected by an ELISA kit, complemented by a comprehensive analysis of milk production parameters, health metrics, reproductive indices, and pharmaceutical expenditures (2021-2024). The results indicated that the paratuberculosis prevalence in the dairy farm gradually reduced from 6.76% (2021) to 3.58% (2024). It was also found that the paratuberculosis prevalence among dairy cows increased progressively with the increase in parity until the fifth calving, after which a significant decline was observed. The reduction in infection rates in the herd was correlated with measurable improvements in milk quality metrics, including elevated milk fat and protein content, extended shelf stability, and decreased somatic cell counts in milk. In addition, the reproductive performance of the dairy cows relatively improved with the decrease in paratuberculosis prevalence; there was a relative improvement in the reproductive performance of the dairy cows, which mainly occurred by the time of pregnancy at the first service of the cows, while the number of monthly occurrences of endometritis, diarrhea, calving intervals, and inseminations decreased. Further data correlation analysis showed that daily milk volume was positively correlated with lactase persistence (95% CI: 0.247-0.753, p = 0.001) and peaked at the day of milk production (95% CI: 0.135-0.698, p = 0.008) but was negatively correlated with parity (95% CI: -0.783--0.315). In addition, lactation time was positively correlated with 305-day milk volume (95% CI: 0.173-0.718, p < 0.004) and peaked at the day of milk production (95% CI: 0.265-0.761) but showed the opposite trend with the milk fat rate (95% CI: -0.633--0.018, p = 0.040) and milk protein rate (95% CI: -0.738--0.215, p = 0.002). Furthermore, milk loss was negatively correlated with peak milk production (95% CI: -0.758--0.258, p = 0.001). Intriguingly, the cost of medications for diarrhea exhibited a downward trend over the past three years. Taken together, these findings confirmed the necessity to reduce the incidence of Mycobacterium avium subsp. paratuberculosis in dairy cows and serve as a guide for the future successful and gradual eradication of paratuberculosis in Chinese dairy cow farms.

The Impact of Mycobacterium avium subsp. paratuberculosis on Intestinal Microbial Community Composition and Diversity in Small-Tail Han Sheep

Paratuberculosis (PTB), primarily caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a chronic infection that affects ruminants and is difficult to prevent, diagnose, and treat. Investigating how MAP infections affect the gut microbiota in sheep can aid in the prevention and treatment of ovine PTB. This study examined fecal samples from eight small-tail Han sheep (STHS) at various stages of infection and from three different field areas. All samples underwent DNA extraction and 16S rRNA sequencing. Among all samples, the phyla p. Firmicutes and p. Bacteroidota exhibited the highest relative abundance. The dominant genera in groups M1-M6 were UCG-005, Christensenellaceae_R-7_group, Rikenellaceae_RC9_gut_group, Akkermansia, UCG-005, and Bacteroides, whereas those in groups A-C were Christensenellaceae_R-7_group, Escherichia-Shigella, and Acinetobacter, respectively. The microbial community structure varied significantly among groups M1-M6. Specifically, 56 microbiota consortia with different taxonomic levels, including the order Clostridiales, were significantly enriched in groups M1-M6, whereas 96 microbiota consortia at different taxonomic levels, including the family Oscillospiraceae, were significantly enriched in groups A-C. To the best of our knowledge, this is the first study to report that MAP infection alters the intestinal microbiota of STHS. Changes in p. Firmicutes abundance can serve as a potential biomarker to distinguish MAP infection and determine the infection stage for its early diagnosis. Our study provides a theoretical basis for the treatment of PTB by regulating the intestinal microbiota, including p. Firmicutes.

Prevalence of bovine paratuberculosis in Chinese cattle populations: a meta-analysis

Background

Bovine paratuberculosis is a chronic infectious disease of ruminants primarily caused by Mycobacterium avium subsp. paratuberculosis (MAP). It is essentially a chronic granulomatous enteritis characterized by intractable diarrhea, progressive lethargy, and thickening of the intestinal mucosa with the formation of crumpled pouches. Bovine paratuberculosis not only adversely affects milk production and the quality of dairy products but also poses a significant threat to the economic development of dairy farming and human food security. This systematic review and meta-analysis was conducted to assess the prevalence of MAP infection among cattle herds in mainland China.

Results

A total of 62 studies with data from 102,340 cattle in 24 provinces in China were selected after matching the assessment criteria. In China, the overall estimated prevalence of MAP infection in cattle was 8%(7727/102340). Interestingly, the MAP infection rate in cattle in southern China was estimated to be 2% (6/281), which was significantly lower compared with other regions of China, and the highest infection rate was 12% (1914/16008) in eastern China. MAP infection rates were related to age, average herd size, type of use, season, detection method, and sample type. Moreover, the MAP infection rate in cattle did not correlate with the publication date of the studies.

Conclusion

The analysis identified age, average herd size, type of use, and season as significant potential risk factors associated with PTB pool positivity. In addition, the detection method and sample type can also potentially affect the incidence of detected PTB.

Individual- and Herd-Level Milk ELISA Test Status and Incidence for Paratuberculosis in Hubei Province, China

Mycobacterium avium subsp. paratuberculosis (MAP) is responsible for the persistent infectious illness known as bovine paratuberculosis, which is one of the most easily overlooked diseases in China amid a lack of epidemiological data. In this study, we evaluated the agreement of milk and blood antibody tests for paratuberculosis and showed an overall agreement of 92.0%, with a 95.0% negative coincidence rate and a 78.6% positive coincidence rate. The milk test was then used to examine the prevalence and incidence of dairy cows in Hubei Province, China. We found that, at the individual level, the highest lacto-prevalence reached up to 22.9%; the farm-level prevalence was as high as 92.3% (12/13) and 84.6% (11/13) in January and April 2018, respectively. The total incidence risk of all farms was 6% per three months. We also found that large-scale farms had a significantly lower prevalence and incidence than small-scale farms. Finally, the correlation between paratuberculosis and milk quality was evaluated, and we confirmed that MAP can significantly alter milk quality and raise somatic cell counts in the milk. This study provides valuable information for assessing the prevalence and incidence risk of paratuberculosis in China. It further provides an essential basis for calling for the prevention and control of paratuberculosis in China.

Prevalence of paratuberculosis in cattle in China: A systematic review and meta-analysis

Bovine paratuberculosis is a chronic infectious disease caused by Mycobacterium avium subspecies paratuberculosis (MAP). Here, a systematic literature review was conducted to investigate the bovine paratuberculosis distribution and associated risk factors in China before 2022. The databases CNKI, VIP, WanFang, PubMed, and ScienceDirect were used to search for articles. The random effect model of the "Meta" package of "R" software was used, and the Arcsine transformation was chosen for the rate conversion analysis. To reveal the factors that led to research heterogeneity, the research data were used for subgroup analysis and univariate meta-regression analysis. Among the 1238 identified articles, 54 met the eligibility criteria. Based on data obtained from the selected articles, the combined positive rate of bovine paratuberculosis was 6.95% in China. In the sampling year subgroup, the positive rate of bovine paratuberculosis before 2013 was 4.94%, which was lower than in other time periods. In the sampling season subgroup, the highest positive rate of bovine paratuberculosis in cattle was 14.60% in the autumn. Furthermore, in the detection method subgroup, the highest positive rate of bovine paratuberculosis was 7.21%, which was detected by using ELISA. In the age subgroup, the positive rate of bovine paratuberculosis was 17.47% in cattle > 12 months old, significantly higher than other age subgroups. The highest positive rate of bovine paratuberculosis was 11.35% for female cattle in the gender subgroup, while in the geographic region subgroup, the highest positive rate was 8.12% for East China, which was significantly higher than in other regions. The highest positive rate of bovine paratuberculosis was for dairy cattle (8.00%), and the highest positive rate by rearing method was 11.03% for non-scale farming. The effects of different geographical and climatic factors on the positive rate of bovine paratuberculosis were evaluated. In summary, we recommend focusing on screening cattle infected with MAP in warm and humid areas.

Immunoinformatics analysis of candidate proteins for controlling bovine paratuberculosis

BACKGROUND

Paratuberculosis is debilitating chronic enteritis usually characterized by diarrhea, decreased milk production, and progressive cachexia. Mycobacterium avium subspecies paratuberculosis (MAP) causes significant economic losses by affecting dairy herds globally. Development of protective vaccines is considered as one of the most effective controlling measures for MAP infections. In the current study, hydrophilic parts of MAP2191 and FAP-P proteins as two vaccine candidates were analyzed using immunoinformatics approaches.

METHODS

After selecting the most hydrophilic parts of MAP2191 and FAP-P, helper and cytotoxic T-cell epitopes of ht-MAP2191 and ht-FAP-P were identified. The immunogenic, toxicity and physicochemical properties were assessed. Secondary structures of these proteins were predicted, and their tertiary structures were modeled, refined, and validated. Linear and conformational epitopes of corresponding B-cells were recognized. Then ht-MAP2191 and ht-FAP-P epitopes were employed for molecular docking simulations.

RESULTS

The results indicated that ht-MAP2191 and ht-FAP-P were immunogenic, non-allergenic, and non-toxic and possess potent T-cell and B-cell epitopes. Eventually, these protein constructs were docked favorably against TLR4.

CONCLUSION

According to the findings, ht-MAP2191 and ht-FAP-P could be effective protein-based vaccine candidates for paratuberculosis. It should be noted that to examine their efficacy, further in vitro and in vivo experiments are underway.

Identification of Mycobacterium avium subspecies paratuberculosis in sheep farms in Bayannaoer, Inner Mongolia, China (short communication)

BACKGROUND

Paratuberculosis is a widespread chronic infection of Mycobacterium avium subspecies paratuberculosis (MAP) that causes significant economic losses to the sheep industry. The current study investigated this disease, which causes diarrhea in sheep, particularly, in Bayannaoer, Inner Mongolia, China. Diagnosis was based on clinical symptoms, pathological autopsy, histopathological inspection, and serological and molecular methods.

RESULTS

MAP was confirmed using polymerase chain reaction using DNA extracted from tissue and fecal samples. Serum samples from 472 individual sheep were obtained to detect antibodies against MAP using an enzyme-linked immunosorbent assay. MAP antibodies were separately detected in 17.86% (35/196) and 18.48% (51/276) of sheep herds at approximately 6 months and ≥ 1 year of age, respectively. The tissue lesion and pathological section results were consistent with paratuberculosis infection.

CONCLUSIONS

To our knowledge, this is the first report of Mycobacterium avium subspecies paratuberculosis seroprevalence in Bayannaoer sheep in Inner Mongolia. Our findings show that MAP is not only prevalent, but also a potential threat to this region. Further investigations, including long-term epidemiological surveillance and isolation are needed for the awareness and effective treatment of paratuberculosis in sheep of Inner Mongolia.