Prevalence Of Paratuberculosis Research Articles

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.

Serological and epidemiological investigation of Mycobacterium avium subspecies paratuberculosis in bovines in Pakistan.

To investigate the prevalence of paratuberculosis in cattle and buffaloes at twelve public dairy farms in Punjab, Pakistan. A total of 2181 more than two-year-old animals (1242 cattle and 939 buffaloes) were tested by avian tuberculin, i.e., killed purified protein derivative (PPD) of Mycobacterium avium paratuberculosis and indirect ELISA. Blood and fecal samples were collected from tuberculin positive animals. These samples were further processed by indirect ELISA. The data were analyzed using frequency analysis and logistic analysis procedures. The prevalence of paratuberculosis at public dairy farms was 3.8%, as determined by tuberculin + ELISA test. It varied from 0.71-13.5% with a 100% herd prevalence. Multivariate logistic regression analysis revealed that species, milk production, total animals, total small ruminants, and total buffaloes were significantly associated with the occurrence of paratuberculosis. Odd ratio analysis revealed that with a one-kilogram increase in body weight, there will be a 0.006% increase in disease occurrence. With the increase in one animal in small ruminants and buffaloes, there will be 0.008% and 0.42% greater chances of developing paratuberculosis, respectively. Bivariate logistic regression analysis of cattle and buffaloes revealed that farm number, age, and total number of cattle were significantly associated with the occurrence of paratuberculosis. A one-month increase in lactation length increases the chance of tuberculosis by 0.004%; similarly, a one-liter increase in milk production increases the chance of disease by 10%. With each additional buffalo in the herd, there will be a 0.007% greater chance for the occurrence of paratuberculosis. This study concluded that tuberculin testing can be used in conjunction with ELISA to screen animals for paratuberculosis in countries with scarce resources, such as Pakistan. The efficacy of disease diagnosis can be improved by combining multiple tests.

Comparison of two serological diagnosis tests for bovine paratuberculosis.

Mycobacterium avium subsp. paratuberculosis (MAP) is the causal agent of paratuberculosis (PTBC), a chronic infectious granulomatous enteritis of ruminants. The PTBC diagnosis with commercial ELISA has limitations in sensitivity and specificity, and its results depend on the state of progress of the disease. This research aimed to evaluate two different ELISAs: (a) an "in-house" ELISA with a sonicated antigen obtained from a MAP I47 strain, and (b) a commercial ELISA. In total, the evaluated sample consisted of 394 bovine serum samples from 12 farms in Argentina with high (5-9%) and low (≤ 0.05%) prevalence of PTBC. The evaluation of the new antigen (2.5µg/mL) was against a 1:50 dilution of the M. phlei faced sera. The cut-off point, sensitivity, and specificity determinations of both techniques were by ROC curve analysis. The area under the curve for the I47 ELISA was 0.9 (CI 95%, 0.93-0.97). With a cut-off point of 8.8%, the sensitivity was 84.3% and the specificity 96.6%. The agreement between both techniques was 0.7 (CI 95%, 0.6-0.8). These results indicate a high discriminative capacity to differentiate positive and negative bovine sera of MAP infection with the I47 ELISA. This result would represent an advantage to dispense with the imported kit.

Prevalence of paratuberculosis in Thuringian sheep and goat flocks

In Germany, only few data on the current distribution of paratuberculosis in sheep and goat flocks is available. The present study provides an overview of the distribution of Mycobacterium avium ssp. paratuberculosis (MAP) in 165 Thuringian sheep and goat flocks. Also, the study investigated the association between the MAP status of the flock and herd specific factors as well as the association between the individual measured value of ELISA and animal specific factors like age, body condition, sex, and animal species. To investigate the prevalence of MAP, serum samples from 2550 sheep and 1171 goats from 165 flocks (flock size 2 to 2879 animals) were serologically examined for MAP antibodies in 2021. Additionally, 1 to 6 environmental faecal samples were collected from every flock depending on the flock size. They were examined for the presence of MAP by using both bacteriological cultivation and a commercially available real-time-PCR. MAP antibodies were detected in 41 sheep (1.6%) and 29 goats (2.5%), which accounts to a detection of MAP antibodies in 20.6% of the 165 flocks (on herd level). The symptoms of paratuberculosis, weight loss with preserved appetite and altered fecal consistency, were observed in only four of the flocks. A positive association was identified between the detection of MAP or MAP-specific antibodies in a flock and flock size, as well as positive association between the measured value in the Elisa (s/p ratio) and the age of the animal. Furthermore, an association between an increasing s/p ratio of the ELISA and a decreasing body condition was found. Given what is known about the distribution of paratuberculosis in small ruminants, this disease should always be considered as a possible cause of weight loss and diarrhea. In case of high within-herd prevalence herd-specific control measures should be considered. In serological herd monitoring, animals with poor body condition should preferably be included in the sample, as the probability of being able to identify MAP positive animals is higher here.

Investigating the Prevalence of Paratuberculosis in Hungarian Large-Scale Dairy Herds and the Success of Control Measures over Four Years.

Paratuberculosis (PTB) is a severe, slow-developing, untreatable disease of ruminants. Worldwide, the disease affects more than 50% of herds in the dairy industry, and causes substantial economic losses for dairy producers. Diagnostic tests show limited sensitivity, especially in the early stages of the disease. Our study aimed to investigate the seroprevalence of Mycobacterium avium ssp. paratuberculosis (MAP) in large-scale dairy herds in Hungary, in association with the self-reported presence or absence of screening and intervention measures against MAP transmission. We processed data from 42 large-scale Holstein Friesian farms in Hungary between 1 January 2018 and 31 December 2021. An average of 32,009 (min.: 31,702; max.: 32,207) animals were blood sampled yearly (127,372 in total during the four years), corresponding to 15% of the Hungarian dairy cattle population. All female cattle older than 2 years were blood sampled on the farms enroled in the study. The samples were tested using a commercial ELISA (IDEXX paratuberculosis screening Ab test). Farm managers were interviewed about their on-farm diagnostic and intervention approaches using a uniform questionnaire, including questions on the level of awareness, frequency of ELISA and PCR testing, and their strategies for culling adult animals and reducing transmission to newborn calves. By comparing the annual rate of change in seroprevalence and the amount of change observed during the four-year period, we concluded that test-and-cull strategies implemented in parallel with newborn calf management that aimed at preventing MAP transmission were superior to test-and-cull strategies alone; moreover, fortifying culling decision making via additional ELISA and PCR tests is superior to using a single ELISA result. For farms that carried out a complex program with both "test-and-cull" and proper newborn calf management, there was a proportional reduction in apparent seroprevalence at an average of 22.8% per year. Fifteen of the sampled farms had no measures in place to control paratuberculosis. On these farms, the seroprevalence increased by 12.1% per year on average.

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.

Prevalence of paratuberculosis in cattle based on gross and microscopic lesions in Ethiopia

BackgroundParatuberculosis, caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a chronic progressive granulomatous enteritis mainly affecting domestic and wild ruminants worldwide. Although paratuberculosis could be prevail in Ethiopia, there is a scarcity of epidemiological data on paratuberculosis in the country. Thus, this study was conducted to estimate the prevalence of paratuberculosis based on gross and microscopic lesions in cattle slaughtered at ELFORA Abattoir, central Ethiopia. Small intestines and associated lymph nodes of 400 apparently healthy cattle which were slaughtered at ELFORA export abattoir were examined for gross and microscopic lesions of paratuberculosis. The microscopic lesions were classified into four grades (I-IV) based on the type and number of cells infiltrated into the lesion. The prevalence of paratuberculosis was estimated on the basis of gross as well as microscopic lesion of paratuberculosis.ResultsThe prevalence of paratuberculosis was 11.25% (95% Confidence interval, CI = 0.083–0.148) on the basis of gross lesion. However, relatively lower prevalence (2.0%, 95% CI = 0.01, 0.039) was recorded based on microscopic lesion. The gross lesions were characterized by intestinal thickening, mucosal corrugations and enlargement of associated mesenteric lymph nodes. On the other hand, the microscopic lesions were characterized by granuloma of different grades ranging from grade I to grade III lesions.ConclusionsThe present study indicated the occurrence of paratuberculosis in cattle of Ethiopia based on the detection of gross and microscopic lesions consistent with the lesion of paratuberculosis. The result of this study could be used as baseline information for future studies on the epidemiology and economic significance of paratuberculosis.

Assessment of Paratuberculosis international official reporting in Europe using the information supplied to the WOAH by National Veterinary Services.

The present study characterizes the epidemiological situation of Paratuberculosis (PTB) in Europe during the last 24 years, using the information officially reported to the World Organisation for Animal Health (WOAH) by veterinary services of the European countries. The prevalence of PTB at country level was described during the study period. A Cox proportional hazards (PH) regression analysis was implemented to evaluate the notification behaviours. Results from this work indicate that the most affected countries are in Southern and Western Europe, whereas PTB presence appears lower in Northern and Eastern Europe. PTB was routinely declared as a notifiable disease in 65% of the countries. Less than 50% of the countries routinely implemented passive surveillance, and only 19%, reported active surveillance for disease detection. Results from the Cox PH regression indicate that the Gross National Income (GNI) per capita and the application of active surveillance significantly influence the recurrence of PTB reporting. In countries with lower and upper middle income, the hazard of recurrence is 0.13 and 0.18 times lower than in countries with high income. The hazard of recurrence in countries that infrequently and moderately applied active surveillance is 1.99 and 1.65 times higher than in countries that routinely applied active surveillance. Findings from this work highlight an important variation in reporting behaviours, disease status and surveillance across Europe.

Prevalence of Mycobacterium avium Subsp. paratuberculosis in Feral Pigeons (Columba livia) Associated with Difficulties Controlling Paratuberculosis in a Bovine Herd (Fighting Bull Breed).

A bovine herd with a high prevalence of paratuberculosis (PTB) cohabiting with a population of pigeons was studied (2011−2020). After finding the disease in 2011, annual monitoring was performed in 2012−2014 by obtaining blood samples for ELISA and intradermal tuberculinization (IT) tests for Mycobacterium avium subsp. paratuberculosis (MAP). Positive animals were eliminated. PTB prevalence dropped from 10% to 0% but returned to similar values (9.5%) after 6 years without tests. In all animals, Ac values according to the optical density (OD) determined by ELISA increased each year and could be used to isolate herds close to the cutoff point to improve PTB control. Possible reservoirs were considered after evaluating the little success of the PTB control program, and the population of feral pigeons was studied. Specifically, 10% of the pigeon population (n = 13) was necropsied. Samples of intestine, feces, and foot skin for PCR study for MAP and samples of terminal intestine for histopathological analysis were taken. Eleven pigeons were PCR-positive against MAP, in the intestine (10/11), foot skin (3/11), and feces (1/11). The presence of MAP in pigeon feet could demonstrate its role as a mechanical disseminator of PTB, while the presence in pigeon intestine and feces could also suggest its role as a reservoir.

Comparative evaluation of various in-house protocols on diagnostic performance for paratuberculosis IS900 PCR.

Paratuberculosis is a worldwide endemic infectious disease of ruminants that results in high economic losses. Public health concerns are also being raised with human Crohn's disease. Therefore, control is becoming priority for governments. Control is largely dependent on "Test and Cull" or "Test and Segregate" policy. Hence, it is critical to assure the infection before making the decision. Commercial kits are costly especially in view of resource limited areas. Present study analyzed the performance various in house DNA isolation methods and PCR master mix combinations to optimize a protocol for confirmation of paratuberculosis bacilli shedding in feces. Present study included five protocols of fecal DNA isolation (chemical, bio-chemical, physio-chemical and physical) and three reaction mixes (based on Qiagen, Genei and Thermo 2X master mixes) in nine different combinations using additives and tested their performance for IS900 PCR. Spiked fecal samples were used to select the best combination of DNA isolation method and PCR master mix (PRM). Selected combination was used to test reference (positive and negative) fecal samples and field samples. Findings revealed that combination physical method of DNA isolation and Genei based PRM (with additives; betaine DMSO and BSA) had lowest limit of detection. Sensitivity was 83% and specificity was 100% in comparison to fecal culture. High prevalence (23%) was reported for paratuberculosis on field samples. Optimized protocol has acceptable sensitivity and can easily be adopted in resource-limited laboratories. High prevalence of paratuberculosis needs immediate implementation of the control strategies.

Estimating the sensitivity and specificity of serum ELISA and pooled and individual fecal PCR for detecting Mycobacterium avium subspecies paratuberculosis in Canadian cow-calf herds using Bayesian latent class models.

While Johne's disease (JD) is less common in beef than in dairy herds, consolidation is increasing transmission risk. Estimates of Mycobacterium avium spp. paratuberculosis (MAP) prevalence and test performance in cow-calf herds are needed to inform control programs. Objectives of this study included describing the prevalence of MAP in Canadian cow-calf herds and comparing the relative performance of a serum ELISA, pooled fecal PCR and individual fecal PCR using Bayesian latent class models, and to investigate factors associated with positive MAP tests. Blood and fecal samples (n = 3,171) were collected from 159 Canadian cow-calf herds. All samples were analyzed using serum ELISA and fecal PCR (pools of five samples) and a subset of 913 fecal samples were also tested with individual PCR. Based on latent class analysis, MAP prevalence was higher in eastern compared to western Canada for both animals {East, 3% [95% Credible Interval (CrI) 1–7%]; West, 1% [95% CrI 0.2–2%]} and herds [East, 15% (95% CrI 2–35%); West, 10% (95% CrI 1–26%), based on one or more positive results]. Sensitivity (Se) and specificity (Sp) for animal level individual PCR were 96% (95% CrI 80–100%) and 98% (95% CrI 96–100%), respectively followed by pooled PCR [Se = 54% (95% CrI 36–72%), Sp > 99.9% (95% CrI 99.8–100%)] and ELISA [Se = 36% (95% CrI 22–52%), Sp = 98% (95% CrI 96–99%)]. Based on 20 samples per herd, the herd level Se of ELISA was 79% (95% CrI 47–100%) (at least one positive sample) compared to 43% (95% CrI 14–94%) for pooled PCR. Herd-level Sp was 99% (95% CrI 96–100%) for pooled PCR and 90% (95% CrI 83–100%) for ELISA. Cows from herds with dairy cattle on farm and cows with symptoms of JD in the past 3 years were more likely to be MAP positive. Herds that had animals with JD symptoms in the previous 3 years and those with more breeding females were most likely to test positive for MAP. While serum ELISA can be effective for herd screening, PCR performed better for animal testing. Pooled PCR testing could be a less costly option; however, determining the most cost-effective approach will require further economic analysis.

Association between calf rearing technology and farm-level paratuberculosis infection in Hungarian dairy farms

The ruminant paratuberculosis (PTB) is a global problem. The disease causes significant economic loss, primarily in dairy farms, due to premature culling, reduced slaughter value, and production losses. Newborn and young calves are the most susceptible to being infected, and the chance of infection decreases with increasing age. Animals are most commonly infected orally.The study aimed to assess the factors that have a greater association with PTB prevalence in Hungarian cattle farms and could play a major role in the eradication process. We visited 26 large-scale Hungarian dairy herds (having preliminary data on PTB and testing positive during the last two years). We assessed 10 management aspects that may influence the spread of PTB. Farms were evaluated, and answers were dichotomised based on whether the given management practice was advantageous or disadvantageous in controlling the spread of MAP. By summing up the obtained values, a ’Hygiene score’ was achieved that would rank the farms based on their awareness in MAP control.In the visited herds, the average apparent animal-level PTB prevalence was 8.3 % (min. 2.0 %, max. 19.5 %). There was a significant negative correlation between the ’Hygiene score’ and the apparent MAP seropositivity of the given farm. Taking the calf away immediately after birth was associated with an average 55 % decrease in the odds of seropositivity as compared to the longer time spent with the dam. Discarding of colostrum from previously PTB+ cows after calving was associated with a 48 % decrease in the odds of seropositivity as compared to farms where the colostrum or milk of PTB+ cows was not discarded but fed to the calves. In conclusion, calf management is key in controlling paratuberculosis where immediate removal of the calf from its mother and the feeding of MAP-free colostrum and milk are essential elements.

Bayesian estimation of sensitivity and specificity of fecal culture, fecal PCR and serum ELISA for diagnosis of Mycobacterium avium subsp. paratuberculosis infections in sheep

The objective of the present study was to evaluate the diagnostic accuracy of the individual fecal culture (IFC), fecal PCR (FPCR), and serum ELISA for the detection of Mycobacterium avium subsp. paratuberculosis (MAP) infections in sheep from four governorates in Egypt, using a latent class model (LCM) fitted within a Bayesian framework. Furthermore, the within-governorate prevalence of MAP infection in sheep was estimated as a secondary objective. Fecal and blood samples were collected from 370 sheep in four Egyptian governorates. Fecal samples were analyzed by IFC and RT-PCR based on ISMav2 gene, while ELISA was performed on serum samples. The sensitivity (Se) and specificity (Sp) of the three diagnostic tests were estimated using a three-tests-four-populations Bayesian LCM to obtain posterior estimates [medians and 95% Bayesian credible intervals (95% BCI)] for each parameter. The median Se estimates (95% BCI) for IFC, FPCR, and serum ELISA were 31.8% (22.8–41.4), 49.7% (31.8–79.9), and 61.2% (39.8–81.4), respectively. The median Sp estimates (95% BCI) for IFC, FPCR, and serum ELISA were 97.7% (96.1–98.9), 97.7% (95.6–99.5), and 98.4% (96.9–99.3), respectively. The median within-governorate paratuberculosis prevalence (95% BCI) was 5.2% (1.1–13.6), 8.4% (2.9–17.7), 9.4% (3.0–20.7), and 18.2% (10.5–29.5) for the Gharbia, Menoufia, Qalyubia, and Kafr El-Sheikh governorates, respectively. In conclusion, at a ratio of the optical density (OD) sample/OD positive control threshold of > 45%, ELISA showed the highest Se among the three tests and comparable Sp to IFC and FPCR. The test ELISA evaluated in this study is an interesting alternative for detecting MAP in sheep due to its higher Se, lower cost, and shorter turnaround laboratory time compared to IFC and FPCR.

Prevalencia de Mycobacterium avium subsp. paratuberculosis y factores de riesgo asociados en lecherías bajo sistemas de sala de ordeño mecánico en Antioquia, Colombia

The present study aimed to determine Mycobacterium avium subsp. paratuberculosis (MAP) prevalence according to environmental samples and to explore the herd-level risk factors associated to MAP infection in dairy herds under mechanical milking parlor and pasture grazing-based systems. The study herds (n= 94) were located in 60 districts from five municipalities in the Northern region of the province of Antioquia, Colombia. Herds were visited once in 2016 to collect two composite environmental samples and to complete a risk assessment questionnaire. MAP identification was carried out using a quantitative real-time PCR method based on the IS900 sequence. A herd was considered as MAP-positive if one or both of the environmental samples were found positive by the molecular technique. The information on risk factors was analyzed using a multivariable logistic regression model. The apparent herd-level prevalence found was 14.9 % (14/94; 95 % CI: 7.7-22.1), ranging from 0 to 33.3 % at municipality-level. Herds where other than Pure-Holstein breeds were predominant (i.e. Jersey, Jersey crossbreeds) were more likely to be MAP-qPCR positively infected than those on which where pure-Holstein cattle was predominant (OR=3.7; 95 % CI: 1.1-15.2). The present study reports MAP prevalence in dairy herds in the province of Antioquia (Colombia), and the association between MAP environmental positivity with the predominant breed in the herd.

Quantitative Risk Assessment of Exposure to Mycobacterium avium subsp. paratuberculosis (MAP) via Different Types of Milk for the Slovenian Consumer.

This study aimed to assess the risk of exposure to Mycobacterium avium subsp. paratuberculosis (MAP) via milk for the Slovenian consumer. MAP is suspected to be associated with several diseases in humans, therefore the risk of exposure should be better understood. The primary source of MAP for humans is thought to be cattle, in which MAP causes paratuberculosis or Johne’s disease. We developed a stochastic quantitative risk assessment model using Monte Carlo simulations. Considering the assumptions and uncertainties, we estimated the overall risk of exposure to MAP via milk to be low. For people consuming raw milk from MAP positive farms, the risk was high. On-farm pasteurisation reduced the risk considerably, but not completely. The risk of exposure via pasteurised retail milk was most likely insignificant. However, with a higher paratuberculosis prevalence the risk would also increase. Given the popularity of raw milk vending machines and homemade dairy products, this risk should not be ignored. To reduce the risk, consumers should heat raw milk before consumption. To prevent a potential public health scare and safeguard farmers’ livelihoods, a reduction in paratuberculosis prevalence should be sought. Our results show that culling clinically infected cows was insufficient to reduce milk contamination with MAP.

First molecular investigation John's disease (paratuberculosis) in water buffalo in Iraq

This study was conducted to exam 100 fecal samples and 50 tissue samples from (100 ) buffaloes above one years at different villages and townships in Al-Najaf governorate from (January 2020 to January 2021) to detect of specific insertion Sequence IS900 in Mycobacterium paratuberculosis (John's disease) nested PCR. Out of 150 (100 fecal and 50 tissue) samples tested by Nested PCR, 14(9.3%) were positive for IS900 specific gen, Significant difference at P<0.05 in molecular result were observed between tissues and fecal samples. The molecular results revealed that 6(6%) out of 100 fecal sample were positive, while 8(16%) of tissue sample were positive for IS900 specific gen . There was no significant difference at P<0.05 in relationship between age gender and location with paratuberculosis prevalence.

Estimating the burden of multiple endemic diseases and health conditions using Bayes’ Theorem: A conditional probability model applied to UK dairy cattle

The Global Burden of Animal Diseases (GBADs) is an international collaboration aiming, in part, to measure and improve societal outcomes from livestock. One GBADs objective is to estimate the economic impact of endemic diseases in livestock. However, if individual disease impact estimates are linearly aggregated without consideration for associations among diseases, there is the potential to double count impacts, overestimating the total burden. Accordingly, the authors propose a method to adjust an array of individual disease impact estimates so that they may be aggregated without overlap. Using Bayes’ Theorem, conditional probabilities were derived from inter-disease odds ratios in the literature. These conditional probabilities were used to calculate the excess probability of disease among animals with associated conditions, or the probability of disease overlap given the odds of coinfection, which were then used to adjust disease impact estimates so that they may be aggregated. The aggregate impacts, or the yield, fertility, and mortality gaps due to disease, were then attributed and valued, generating disease-specific losses. The approach was illustrated using an example dairy cattle system with input values and supporting parameters from the UK, with 13 diseases and health conditions endemic to UK dairy cattle: cystic ovary, disease caused by gastrointestinal nematodes, displaced abomasum, dystocia, fasciolosis, lameness, mastitis, metritis, milk fever, neosporosis, paratuberculosis, retained placenta, and subclinical ketosis. The diseases and conditions modelled resulted in total adjusted losses of £ 404/cow/year, equivalent to herd-level losses of £ 60,000/year. Unadjusted aggregation methods suggested losses 14–61% greater. Although lameness was identified as the costliest condition (28% of total losses), variations in the prevalence of fasciolosis, neosporosis, and paratuberculosis (only a combined 22% of total losses) were nearly as impactful individually as variations in the prevalence of lameness. The results suggest that from a disease control policy perspective, the costliness of a disease may not always be the best indicator of the investment its control warrants; the costliness rankings varied across approaches and total losses were found to be surprisingly sensitive to variations in the prevalence of relatively uncostly diseases. This approach allows for disease impact estimates to be aggregated without double counting. It can be applied to any livestock system in any region with any set of endemic diseases, and can be updated as new prevalence, impact, and disease association data become available. This approach also provides researchers and policymakers an alternative tool to rank prevention priorities.

First identification of Mycobacterium avium subsp. paratuberculosis in wild ruminants in a zoo in Mexico.

Background and Aim:Paratuberculosis (PTB) is an infectious disease that induces chronic enteritis in ruminants. It is caused by Mycobacterium avium subsp. paratuberculosis (MAP). In this study, we evaluated the presence of MAP using bacteriological, molecular, and anatomopathological studies, based on the clinical suspicion of PTB in a zoo, in an area housing 10 scimitar-horned oryx (Oryx dammah), five giraffes (Giraffa camelopardalis), and three blue wildebeests (Connochaetes taurinus).Materials and Methods:From November 2016 to June 2017, fecal samples were collected from individuals of the three species on four occasions, resulting in a total of 56 fecal samples. In addition, five small intestine samples were collected from the necropsies of three adult scimitar-horned oryx females and two oryx calves. MAP identification was performed through isolation in Herrold’s medium with egg yolk, mycobactin, and sodium pyruvate, Ziehl–Neelsen staining, IS900 polymerase chain reaction (IS900 PCR), and anatomopathological examination of intestine samples.Results:Diffuse granulomatous enteritis with abundant acid-fast bacilli was found in two out of five intestine samples from adult scimitar-horned oryx females. MAP was isolated in 7/56 (12.5%) of the fecal samples from four scimitar-horned oryx, one giraffe, and two wildebeest samples. Two out of 5 (40%) samples obtained from scimitar-horned oryx tested positive. IS900 PCR yielded five positive samples (two fecal samples and three small intestine samples). MAP isolates were classified as Type C (Cattle) using type-specific PCR.Conclusion:These results demonstrated the presence of MAP in the area evaluated and indicated the importance of both sampling live animals and conducting postmortem examinations. The use of bacteriological and histopathological diagnostic techniques demonstrated in this study will provide insight into the health status and prevalence of paratuberculosis in wild ruminants under human care.

Herd Prevalence Estimation of Mycobacterium avium Subspecies paratuberculosis Burden in the Three Main Dairy Production Regions of Germany (PraeMAP).

Simple SummaryParatuberculosis, caused by Mycobacterium avium ssp. paratuberculosis (MAP), is widely spread among ruminants worldwide. After a long-lasting incubation period, infected animals suffer from chronic granulomatous enteritis. Economic losses are caused by premature culling, reduced milk yield and slaughter value in the dairy and beef industry, triggering attempts to control the disease. Paratuberculosis is a listed disease (category E), according to the European Animal Health Law, and intended to be monitored within the European Union. Evaluation of several herd-level monitoring approaches including the testing of environmental fecal samples to detect the infectious agent have been evaluated, proving environmental sampling to be a useful monitoring tool on herd level. This study comprises the application of environmental sampling within a herd prevalence estimation study in German dairy herds. Based on regional differences in the structure of livestock farming, Germany was divided into three regions where a representative number of farms were visited for sample collection. The results clearly indicate a different regional MAP herd level prevalence. The highest percentage of affected herds is found in the eastern part with large dairy herds, and the lowest in the south with the smallest average herd size. We conclude that the regional differences in MAP prevalence imply different approaches to control the disease.On-farm environmental sampling is an effective method for herd-level diagnosis of Mycobacterium avium ssp. paratuberculosis (MAP) infection and between-herd prevalence estimation. So far, no prevalence study enrolling important livestock-farming regions has been conducted. As the structure of dairy farming differs between main livestock-farming regions in Germany, our objective was to assess the between-herd prevalence of paratuberculosis for these regions in a standardized approach. Methods: In total, 457 randomly selected dairy farms from three regions of Germany (North: 183, East: 170, South: 104) were sampled between 2017 and 2019. Environmental samples (boot-swabs, aggregate feces and/or liquid manure samples) were cultured and analyzed using an IS900-qPCR for MAP determination. Of the 457 selected farms, 94 had at least one MAP-positive environmental sample with significant differences between regions regarding the apparent (North: 12.0%, East: 40.6%, South: 2.9%) or corrected true (North: 14.8%, East: 50.1%, South: 3.6%) between-herd prevalence. In conclusion, regional differences of between-herd prevalence of paratuberculosis are substantial in Germany, indicating the need for control approaches with different aims. Taking into account regional MAP prevalence, MAP-control programs should focus on on-farm prevalence reduction or on mitigating the risk of between-herd transmission, depending on region.

Evaluation of using comparative intradermal tuberculin test to diagnose bovine tuberculosis in dairy cattle in Taiwan.

The National Bovine Tuberculosis (bTB) Eradication Program for dairy cattle has been operating in Taiwan for many years and has allowed the prevalence of bTB to decrease gradually. However, 29% of intradermal tuberculin test (ITT)-positive dairy cows were later found to be TB negative based on necropsy, histopathological examination, and mycobacterial isolation results. Studies in Taiwan have indicated that Mycobacterium avium subsp. paratuberculosis (MAP) may lead to false-positive ITT. Due to the high prevalence (over 90%) of paratuberculosis (PTB) serum antibody among Taiwan's farms, comparative ITT (CITT) has been recommended to differentiate between bTB and PTB infections. In this study, we used ITT, CITT, and enzyme-linked immunosorbent assay (ELISA) to evaluate the prevalence of bTB from 2012 to 2018. We also used pathological and bacterial examination from ITT-positive dairy cows to evaluate CITT's diagnostic ability and adjust its cutoff point accordingly. After careful selection, 36 cows (including 31 cows from 11 ITT-positive farms and 5 from 2 ITT-negative farms) were examined by CITT. The cutoff point was adjusted using a receiver operating characteristic (ROC) analysis. Overall, our results identified the ITT-positive prevalence in Taiwan as 0.03-0.22%, and PTB-positive prevalence as 54.55-73.53%. The results of sensitivity, specificity, kappa, and ROC analyses have identified the optimal cutoff point for the CITT in Taiwan as ≥ 3mm. At this cutoff point value, the sensitivity and specificity were 62.5% and 96.43%, respectively. Our findings can be used to reduce the false-positive response rate caused by PTB cross-reaction and accelerate the eradication of bTB in Taiwan.