Contagious Agalactia In Sheep Research Articles

Influence of Natural and Climatic Conditions on the Distribution and Forms of Contagious Agalactia in Sheep in Bessarabia, Ukraine.

Contagious agalactia of ruminants is an endemic disease caused by Mycoplasma agalactiae in flicting significant losses on farms in deaths and forced slaughter of sick animals, abortions, births of sick young animals, and reduced milk and wool production. The aim of the study was to determine the influence of hydrometeorological conditions on the distribution and forms of contagious agalactia in sheep in Bessarabia, Ukraine. The epizootic situation regarding contagious agalactia was studied during 2011-2021 on sheep farms in the south of the Odesa region in Bessarabia. Over two million blood samples from sheep aged 1-6 years were serologically investigated and the prevalence of agalactia was correlated with Selyaninov's hydrothermal coefficient for each sampling year. High rates of infection of sheep with contagious agalactia (from 13.1% to 14.4%) were registered in 2012, 2016 and 2021, years which according to the hydrothermal coefficient of 1.0 were sufficiently moist. The lowest incidence rates, from 6.5% to 7.4%, were registered in the very dry 2013, 2014 and 2019 with hydrothermal coefficients of 0.5‒0.6. In sufficiently moist years, contagious agalactia of sheep manifested itself in the mastitic form, while in the dry period the mastitic form was half as prevalent, and the mixed, articular and ocular forms of the disease proliferated. The results indicate the circulation of Mycoplasma agalactiae among small ruminants in Bessarabia, and that the prevalence and the course of the associated disease depend on the humidity of the climate, i.e. the value of the hydrothermal coefficient.

Age and Seasonal Pattern of Contagious Agalactia in Small Ruminants in Ukraine.

IntroductionThe aim of the study was to determine how the spread of contagious agalactia in sheep and goats in the Odesa region depended on the age of the animals and the season.Material and MethodsFrom January 2016 to December 2018, 1,964 ewes and 1,484 nanny goats of different age groups were studied by ELISA for antibodies to Mycoplasma agalactiae.ResultsThe highest incidence of contagious agalactia was registered in one-year-old animals and was 59.7‒83.0%, two-year-old ruminants showed 17.0‒40.3% prevalence, in livestock at the age of 3–4 years no serological evidence of the disease was registered and in ewes and nanny goats older than 5–6 years 1.5–3.6% were infected. The most susceptible were young animals at the age of one-month (11.6‒14.5%). The first peak of the disease was recorded in March‒April (21.0‒26.1%), in the lambing period, which coincided with the beginning of lactation and the suckling period, and the second peak occurred in June–July (28.9‒34.2%), the period of maximum lactation and of manual milking of sheep and goats.ConclusionThe results of serological investigations indicate the circulation of M. agalactiae in small ruminants in the south of Ukraine. To avoid greater dissemination of the pathogen, appropriate measures should be applied and strategies for its control need to be drawn up.

Determination of Contagious Agalactia in Sheep and Goats and Investigation of Antibiotic Susceptibility of Mycoplasma spp. Positive Isolates

Antibiotic resistance is one of the most important issues encountered globally in managing infectious diseases and is a potential problem in the treatment of Mycoplasma infections. The aims of this study were to: determine carrier rates in sick and healthy herds of sheep and goats; determine the presence in herds of carrier animals that were clinically asymptomatic for contagious agalactia and use antibiogram tests to investigate the susceptibility to antibiotics of Mycoplasma spp. positive isolates derived from sheep and goat ear swabs. The presence of contagious agalactia was diagnosed by analyzing ear swabs (n = 300, bacterial method, Mycoplasma spp.) and blood serum samples (n = 300, serological method [ELISA], Mycoplasma agalactiae) taken from sheep and goat herds located in Elazýð and Malatya provinces in eastern Turkey. The ELISA tests revealed seropositivity in 10 (3.33%) of 300 samples. In order to determine the most effective antibiotic for disease treatment, antibiogram testing was performed on 87 (29%) positive isolates that had been isolated from swab cultures. We determined tulathromycin (MIC 16 µg/mL) and tiamulin (MIC 16 µg/mL) to be the most effective antibiotics, whereas disease agents were resistant to trimethoprim/sulfamethoxazole and neomycin.

Biochemical parameters of blood sera of sheep vaccinated against Contagious agalactia

The paper presents data on the positive effect of the inactivated vaccine against contagious agalactia of sheep and goats developed in the National Scientific Center ‘Institute of Experimental and Clinical Veterinary Medicine’ (Kharkiv, Ukraine) on the biochemical and immunological parameters of sheep blood serum. It has been proved that the vaccine is not reactogenic, does not have immunosuppressive action and corrects the recovery of serum albumin concentration in vaccinated sheep, namely by reducing α-globulins by 28.5% and β-globulins by 36.8% and has a positive effect on the growth of γ-globulin by 31.5%, activating the humoral level of immunity

Contagious Agalactia In Sheep And Goats: Current Perspectives.

Contagious agalactia (CA) is a disease caused equally by four Mycoplasma species, in single or mixed infections. Clinical signs are multiple, including mastitis, arthritis, keratoconjunctivitis, pneumonia, and septicemia, non-specific, and expressed differently depending whether sheep or goats are affected, on causative mycoplasmas as well as type of husbandry. CA has been reported worldwide and its geographic distribution maps to that of small ruminant breeding areas. However, as current diagnostic tests are expensive and difficult to implement, it is certainly underdiagnosed and prevalence data are only available for a few countries. CA control relies on vaccines, chemotherapy and good herd management practices. It requires long-term commitment but is often unsuccessful, with frequent clinical relapses. The persistence of the etiological agents, despite their overall susceptibility to antimicrobials, comes from their genetic plasticity and capacity to escape the host immune response. The existence of asymptomatic carriers and the numerous sources of infections contribute to rapid spread of the disease and complicate the control and prevention efforts. Here we review all these aspects in order to highlight recent progress made and identify gaps in knowledge or tools needed for better disease management. Discussion also underlines the detrimental effect of contagious agalactia on small ruminant welfare.

An outbreak of contagious agalactia in sheep

An outbreak of contagious agalactia in sheep

Розробка технології виготовлення вітчизняної вакцини проти інфекційної агалактії овець і кіз

Розробка технології виготовлення вітчизняної вакцини проти інфекційної агалактії овець і кіз

Discrimination between Mycoplasma mycoides subsp. capri and Mycoplasma capricolum subsp. capricolum using PCR-RFLP and PCR

In this study, the dihydrolipoyl dehydrogenase (lpdA) gene was used to distinguish Mycoplasma mycoides subsp. capri (Mmc) from Mycoplasma capricolum subsp. capricolum (Mcc), two of four Mycoplasma species that cause contagious agalactia in sheep and goats. After alignment of nucleotide sequences of both species, specific primer sets were designed from unchanging and variable gene segments. The first primer set LPD-C1-F/LPD-C1-R was used to amplify a 911 bp fragment that was subsequently co-digested with FastDigest PstI, SspI, EcoRI and ClaI enzymes. The PCR-RFLP profiles differentiated the two mycoplasma species. The second primer set was used to distinguish Mmc from Mcc by single tube PCR. Both methods were further applied to identify 54 isolates collected from dairy herds from different provinces in Sardinia. The results of this study showed that PCR-RFLP and PCR could be used in routine diagnosis for rapid and specific simultaneous discrimination of Mmc and Mcc.

A comparison of the efficacy of commercial and experimental vaccines for contagious agalactia in sheep

An effective vaccine that improves the control of contagious agalactia in Mediterranean regions would be beneficial for poorer farmers who use traditional husbandry methods for sheep and goat production. However while there is little published data on the efficacy of commercially available vaccines for contagious agalactia, evidence from the field suggests that some provide inadequate protection. This paper compares four different vaccine formulations, including a widely used commercial vaccine, using clinical signs and mycoplasma excretion as measures of protection in sheep. Results showed that protection afforded by the vaccines, following contact challenge with experimentally infected ewes, varied considerably. A live attenuated vaccine, presently forbidden in the European Union, conferred the best clinical protection, despite a lack of serological response, followed by a vaccine prepared by inactivating the mycoplasmas with saponin. A commercial vaccine inactivated with formalin provided no protection against this disease.

Timing of activation of CD4+ memory cells as a possible marker to establish the efficacy of vaccines against contagious agalactia in sheep

Mycoplasma agalactiae is a major pathogen of sheep and goats in many areas of the world and particularly in Mediterranean countries. It causes contagious agalactia, an infectious disease primarily affecting mammary glands. Many vaccines against the pathogen are currently under development. The aim of the study was to investigate the involvement of T cell-mediated immunity during vaccination and challenge experiments against Mycoplasma agalactiae. A comparison of the antigen-specific expansion of interferon gamma positive T cell memory and naïve subsets was performed between vaccinated and non-vaccinated sheep to identify cellular subsets whose activation was different between protected and non-protected sheep. Data reported in this manuscript demonstrated that two out of the three vaccines used in this study protected sheep from the disease. In the protected groups CD4+ memory interferon-γ+ T cells underwent an early expansion (p<0.05 when compared to unprotected groups), whilst memory CD8+ Interferon-γ+ T cells increased in non-protected animals 7 days after infection (p<0.05). γδ+ Interferon-γ+ T cells reached peaks of expansion in infected and in two vaccinated groups thus indicating that these cells are not preferentially involved in protection or pathogenesis (p<0.05).Hereby we propose that the early activation of CD4+ memory Interferon-γ+ T cells could be considered as a marker of protection from the disease as well as a tool to establish vaccine efficacy.

Application of PCR for diagnosis of contagious Agalactia in Khuzestan Province-Iran

DNA amplification technique which is called PCR is a precise and specific test method and nowadays is also used for identification of Mycoplasma, the causative agent of contagious agalactia in sheep and goats. It also avoids the antigenic cross reaction and variability that hamper serological methods. Several sets of primers are available for different members of Mycoplasma such as Mycoplasma agalactia, Mycoplasma capricolum, Mycoplasma mycoides, and Mycoplasma putrifaciens, which cause the enzootic infections frequently, in some area of Iran, even in Ahvaz, the central city of Khuzestan province. Several methods for the detection of Mycoplasma such as culturing and serological tests have been published. These tests would require by making the culture media (agar and liquid media), time consuming about (3 to 5 weeks to grow detectable colony), and even some Mycoplasma species were difficult to detect with these methods. A specific PCR assay was developed as a diagnostic test, for detection ofMycoplasma infections, carried out for evaluating 47 samples of synovial fluid, milk and eye swabs from sheep's and goats which about 19.1% of them were showed positive forM. agalactia. According to our results only few samples grew in culture, (8.51%). Use of PCR test with high specificity and sensitivity for detection of Mycoplasma has become increasingly widespread, therefore for a quick detection of infection caused by M. agalactia, PCR test application is recommended. Key words: Sheep, goat, milk, Mycoplasma, contagious agalactia.

Endemic Contagious Agalactia in Sheep and Goats: Clinical Evaluation, Treatment and Vaccination

Endemic Contagious Agalactia in Sheep and Goats: Clinical Evaluation, Treatment and Vaccination

Xer1-Mediated Site-Specific DNA Inversions and Excisions in Mycoplasma agalactiae

Surface antigen variation in Mycoplasma agalactiae, the etiologic agent of contagious agalactia in sheep and goats, is governed by site-specific recombination within the vpma multigene locus encoding the Vpma family of variable surface lipoproteins. This high-frequency Vpma phase switching was previously shown to be mediated by a Xer1 recombinase encoded adjacent to the vpma locus. In this study, it was demonstrated in Escherichia coli that the Xer1 recombinase is responsible for catalyzing vpma gene inversions between recombination sites (RS) located in the 5'-untranslated region (UTR) in all six vpma genes, causing cleavage and strand exchange within a 21-bp conserved region that serves as a recognition sequence. It was further shown that the outcome of the site-specific recombination event depends on the orientation of the two vpma RS, as direct or inverted repeats. While recombination between inverted vpma RS led to inversions, recombination between direct repeat vpma RS led to excisions. Using a newly developed excision assay based on the lacZ reporter system, we were able to successfully demonstrate under native conditions that such Xer1-mediated excisions can indeed also occur in the M. agalactiae type strain PG2, whereas they were not observed in the control xer1-disrupted VpmaY phase-locked mutant (PLMY), which lacks Xer1 recombinase. Unless there are specific regulatory mechanisms preventing such excisions, this might be the cost that the pathogen has to render at the population level for maintaining this high-frequency phase variation machinery.

Mycoplasma agalactiae p40 Gene, a Novel Marker for Diagnosis of Contagious Agalactia in Sheep by Real-Time PCR: Assessment of Analytical Performance and In-House Validation Using Naturally Contaminated Milk Samples

We evaluated the capacity of the Mycoplasma agalactiae p40 gene as a diagnostic marker for contagious agalactia in sheep by quantitative real-time PCR. The p40 gene encodes an immunodominant adhesin that plays a key role in cytoadhesion of M. agalactiae. The assay was 100% specific, with an analytical sensitivity of 1 genome equivalent (GE), a quantification that is highly linear (R(2) > 0.992) and efficient (PCR efficiency, >0.992) over a 6-log dynamic range, down to 10 GE. We evaluated the capacity of the assay to detect Mycoplasma agalactiae in 797 milk samples (373 raw sheep milk samples from refrigerated tanks of different farms and 424 milk samples from individual sheep of a flock positive for M. agalactiae). In parallel, we also tested the samples by using microbiological isolation coupled with microscopy identification and by a PCR method recommended by the World Organization for Animal Health. While our assay was able to detect 57 (15.28%) positive samples of the 373 milk samples from different farms, identification by microbiological isolation coupled with microscopy detected only 36 (9.65%) samples, and the conventional PCR detected 31 (8.31%) samples. These findings showed that our assay based on the p40 gene is more specific and sensitive for the detection of M. agalactiae in actual natural samples and, thus, can be a promising alternative tool for diagnosis and epidemiological studies of M. agalactiae infection.

Detection of Mycoplasma agalactiae by Polymerase Chain Reaction in Jordanian Sheep and Goat Herds

The aim of the study was to ascertain whether sheep and goats from selected Jordanian herds were infected with Mycoplasma agalactiae, the most common aetiological agent of contagious agalactia of sheep and goats. All examined animals showed clinical signs of disease at the time of sample collection. The group included 35 animals, 15 sheep and 20 goats. For microbiological examination, a total of 107 swabs were taken from conjunctival, nasal, vaginal or preputial mucosae and from the external auditory canal. Identification of the species isolated was carried out by a polymerase chain reaction. Of the 35 animals, 21 (4 sheep and 17 goats) tested positive for Mycoplasma agalactiae. These results confirmed our assumption that this mycoplasma species is present in Jordanian herds and, for the first time, provided evidence that contagious agalactia of sheep and goats occurs in Jordan.

Construction of the first shuttle vectors for gene cloning and homologous recombination in Mycoplasma agalactiae

Mycoplasma agalactiae is a worldwide ruminant pathogen that causes significant economic losses by inflicting contagious agalactia in sheep and goats. The development of efficient control strategies requires a better understanding of the mycoplasma factors that promote successful infection. However, lack of genetic tools has been a major impediment in studying the pathogenic mechanisms of M. agalactiae. This study describes the identification and cloning of the M. agalactiae origin of replication ( oriC) in order to construct the first shuttle vectors for targeted gene disruption, gene complementation and expression studies. Additionally, this report provides the first evidence of the occurrence of homologous recombination and the functionality of heterologous tetM determinant in this pathogen.

Detection of Mycoplasma agalactiae Antigen in Sheep and Goats by Monoclonal Antibody-Based Sandwich ELISA

Zendulkova D., H. J. Ball, A. Madanat, P. Lany, Z. Pospi‰il: Detection of Mycoplasma agalactiae Antigen in Sheep and Goats by a Monoclonal Antibody- Based Sandwich ELISA, Acta Vet. Brno 2004, 73: 461-464. A preliminary epidemiological survey was carried out to find out whether contagious agalactia of sheep and goats was present in herds in the Czech Republic or Jordan. A total of 99 animals were examined for the presence of Mycoplasma agalactiaeantigen; there were 64 animals from the Czech Republic and 35 from Jordan. All Jordanian animals showed signs of clinical disease. Biological materials for examination included 353 swabs (133 from sheep and 220 from goats) collected from conjunctival, nasal and vaginal mucosae and the external ear canal. A monoclonal antibody-based sandwich ELISA was used to detect the antigen. The results were positive in 11 animals, ambiguous in 10 animals and negative in the rest of them (78). They confirmed our assumption that the Czech Republic is still free from contagious agalactia of sheep and goats but demonstrated that Jordanian herds of small ruminants are infected with Mycoplasma agalactiae. Sheep, goats, contagious agalactia, antigen, Mycoplasma agalactiae, ELISA

Prevalence of Mycoplasma agalactiae Antibodies in Czech and Jordanian Herds of Small Ruminants

Madanat A., D. Zendulkova, P. Lany, Z. Pospi‰il, P. âihal: Prevalence of Mycoplasma agalactiae Antibodies in Czech and Jordanian Herds of Small Ruminants. Acta Vet. Brno 2002, 71: 37-44. We investigated the presence of antibodies against Mycoplasma agalactiae, a causal agent of contagious agalactia, in herds of small ruminants. Eighty serum samples collected from 60 sheep and 20 goats in the Czech Republic and 137 samples collected from 78 sheep and 59 goats in Jordan were examined in our laboratory. Only the Jordan animals showed clinical signs of the disease. The sera were analysed for the presence of antibodies by a specific enzyme immunoassay. Of the 137 Jordan sera, eight gave positive reactions, 11 reactions were dubious and 117 were negative. All sera from the Czech animals showed negative reactions. The results provide evidence that, as expected, the Czech Republic is currently free from the mycoplasma agent causing contagious agalactia of sheep and goats and that, in Jordan as well as in many other Arabic countries, this disease is a frequent and serious health problem in herds of small ruminants. Sheep, goat, contagious agalactia, serum antibody, Mycoplasma agalactiae, enzyme immunoassay

Contagious Agalactia of Sheep and Goats. A Review

Contagious Agalactia of Sheep and Goats. A Review

Contagious agalactia of sheep and goats: Immunity of lactating ewes vaccinated before mating with live or dead vaccines

Groups of ewes were vaccinated before mating with an attenuated Mycoplasma agalactiae strain (AIK40), the same strain after further agar passage (AIK69) and a concentrated formalised mycoplasma cell vaccine emulsified in oil and Falba. No symptoms resulted from inoculation with the live vaccines, but the dead vaccine caused local abscesses at the inoculation site. All the vaccinated animals produced full term lambs. The ewes in all 3 vaccinated groups had a good immunity to subcutaneous challenge with a virulent strain which produced clinical contagious agalactia in all the control animals. Vaccinated ewes infected by the teat canal had a transient infection of the udder which did not generalise, whereas a control ewe developed severe mastitis and a generalised infection.