Mycoplasma infections in small ruminants

The Development and Evaluation of a New Inactivated Vaccine against Mycoplasma capricolum subsp. capricolum

Mycoplasma capricolum subsp. capricolum (Mcc) and Mycoplasma capricolum subsp. capripneumoniae (Mccp) are pathogens that affect large and small ruminants. Indeed, Mcc affects both sheep and goats, causing contagious agalactia (CA). Mccp affects only goats, causing contagious caprine pleuropneumonia (CCPP). CA and CCPP are mainly controlled using inactivated Mcc and Mccp vaccines. However, producing the vaccine with the Mccp strain is complex, fastidious, and costly due to the slow growth of the bacterium. In this study, we present new oil-adjuvanted and inactivated Mcc and Mccp vaccines for sheep and goats against CA and CCPP. The vaccines were evaluated for safety and efficacy using experimental infection. A serological response was observed one week after of the first vaccination of sheep and goats with Mcc and goats with Mccp. The vaccinated animals were subsequently challenged with the virulent Mcc MOR20 strain. The Mcc vaccine was demonstrated to provide robust protection when the animals were challenged with Mcc MOR20. Cross-protection against the Mcc MOR20 challenge was also obtained with the Mccp vaccine. This finding revealed, for the first time, the safety and efficacy of an inactivated Mcc vaccine against contagious agalactia and cross-protection between Mcc and Mccp strains.

Wildlife-Livestock Host Community Maintains Simultaneous Epidemiologic Cycles of Mycoplasma conjunctivae in a Mountain Ecosystem

Infectious keratoconjunctivitis (IKC) is an eye disease caused by Mycoplasma conjunctivae that affects domestic and wild caprines, including Iberian ibex (Capra pyrenaica), a medium-sized mountain ungulate. However, its role in IKC dynamics in multi-host communities has been poorly studied. This study assessed M. conjunctivae in Iberian ibex and seasonally sympatric domestic small ruminants in the Natural Space of Sierra Nevada (NSSN), a mountain habitat in southern Spain. From 2015 to 2017, eye swabs were collected from 147 ibexes (46 subadults, 101 adults) and 169 adult domestic small ruminants (101 sheep, 68 goats). Mycoplasma conjunctivae was investigated through real-time qPCR and statistically assessed according to species, sex, age category, year, period, and area. The lppS gene of M. conjunctivae was sequenced and phylogenetically analysed. Mycoplasma conjunctivae was endemic and asymptomatic in the host community of the NSSN. Three genetic clusters were shared by ibex and livestock, and one was identified only in sheep, although each host species could maintain the infection independently. Naïve subadults maintained endemic infection in Iberian ibex, with an epizootic outbreak in 2017 when the infection spread to adults. Wild ungulates are epidemiologically key in maintaining and spreading IKC and other shared diseases among spatially segregated livestock flocks.

The role of Mycoplasma ovipneumoniae and Mycoplasma arginini in the respiratory mycoplasmosis of sheep and goats in Italy: Correlation of molecular data with histopathological features

Mycoplasma infections are commonly found in the respiratory system of small ruminants; the species most commonly detected are Mycoplasma ovipneumoniae and Mycoplasma arginini, associated with the so-called "atypical non-progressive pneumonia". The pathogenic role of M. ovipneumoniae in pneumonia has been demonstrated in sheep but still needs to be verified in goats; on the other hand, the role of M. arginini in sheep is not well understood, while in goats seems to be of low pathogenic value. The present study aims to investigate the aetiology of pneumonia in sheep and goats that died from respiratory disease using anatomopathological, histopathological, and molecular investigations and to clarify the role of respiratory mycoplasmas by the association of molecular data with histopathological features. First, to better understand which histological changes are actually suggestive of atypical pneumonia in sheep and goats, the study identified the histological lesions significantly associated with Mycoplasma spp. infection. Then, the histological score of lesions considered suggestive of atypical pneumonia was used to estimate the pathogenicity of each mycoplasma detected. The results showed that M. ovipneumoniae and M. arginini (alone or in mixed infections) are pathogenic both in sheep, as well as in goats with similar histology and severity of lesions. Moreover, young animals were statistically more susceptible to M.ovipneumoniae and M. arginini infection than adults. Animals appeared more at risk to the development of M. ovipneumoniae and M. arginini infection in summer.

Clinical, histopathological, and molecular characterization of Mycoplasma species in sheep and goats in Egypt

Background and Aim:

Mycoplasma infection in small ruminants is a serious problem in sheep and goat herds around the world. It is responsible for high economic losses and decreased animal productivity. This study aimed to highlight the clinical, histopathological, minimum inhibitory concentration (MIC), and molecular characterization of Mycoplasma species in sheep and goats in Menoufiya Governorate, Egypt.

Materials and Methods:

A total of 234 samples were collected; 104 samples were collected from pneumonic lung tissues from the abattoir, in addition, 10 and 20 samples collected from apparently and diseased sheep, respectively, and 40 and 60 samples were collected from apparently and diseased goats, respectively, which were subjected to isolation onto pleuropneumonia-like organism medium. Polymerase chain reaction (PCR), histopathological examination, and determination of the MIC were also performed.

Results:

Of 104 samples of lung tissues showing pneumonic lesions, 56 (53.84%) were positive for Mycoplasma isolation. The positive isolation of Mycoplasma from 10 and 20 samples from apparently and diseased sheep was 30% and 40%, respectively as well as the positive isolation of Mycoplasma was 17% and 56.66% out of 40 and 60 apparently healthy and diseased field goat’s cases, respectively. All the diseased sheep and goats showed respiratory manifestations, including cough, bilateral nasal discharge, conjunctivitis, and systemic reaction. Evaluation of the MIC for Mycoplasmaovipneumoniae revealed that lincospectin and tylosin were the most effective antibiotics at 2.5 mg/mL. Histopathological examination of affected lung tissue showed extensive hemorrhagic pneumonia with extensive alveolar hemorrhage. The PCR technique proved to be a rapid, specific, and sensitive method for the detection of M. ovipneumoniae and Mycoplasma arginini at 390 and 326 bp, respectively.

Conclusion:

M. ovipneumoniae and M. arginini were the most prevalent species associated with respiratory infections in sheep and goats in the study area. Further studies are needed to investigate the role of these species in dissemination of the disease within herds of small ruminants.

Molecular detection and phylogenetic analysis of Mycoplasma Spp. isolated from awassi sheep in Al-Muthana Province, Iraq

This study was carried out for molecular detection and phylogenetic analysis of Mycoplasma spp. in Awassi sheep in Al-Muthana province, Iraq. A total of 270 milk samples and swabs were collected from infected sheep. A polymerase chain reaction (PCR) technique was performed to detect a specific 16S rRNA gene of Mycoplasma spp. in these samples. Forty-four positive samples (16.2%) were identified, from which eight samples were selected for partial-gene sequencing. Then, alignment, com-parison with referencing isolates in GenBank, and phylogenetic tree were performed using mean (UPGMA tree) in a MEGA software. The analyses revealed high homology between the current Iraqi isolates and American and Sweden Mycoplasma strains. The present molecular study showed that the studied Iraqi Awassi sheep were infected with Mycoplasma spp. with higher detection percentage from ocular swabs than from other types of samples. The phylogenic analysis registered eight Iraqi isolates with accession numbers in the GenBank with high similarity to five referencing Mycoplasma species.

Bronchopneumonia in Swedish lambs: a study of pathological changes and bacteriological agents

Background

One of the most common post-mortem inspection finding of sheep and lambs in Sweden, following routine slaughter is pneumonia and its prevalence is increasing. To our knowledge, the aetiology of pneumonia in lambs is not well-known for Swedish conditions. Chronic bronchopneumonia, also known as “atypical” or chronic non-progressive pneumonia, is a common disease worldwide, affecting lambs up to 12 months old. It is therefore of interest to elucidate if this disease complex is also a common cause of pneumonia among Swedish lambs. Chronic bronchopneumonia has a characteristic macroscopic and histopathologic appearance, and Mycoplasma ovipneumoniae is the microbial agent most frequently found. Although this bacterium is important for the pathogenesis, multiple agents are presumed to be involved. The aim of this study was to describe the macroscopic and histopathologic lung lesions in routinely slaughtered lambs with pneumonia, and to determine the bacterial agents involved.

Results

A total of 41 lungs with gross lesions consistent with pneumonia were examined. Of these, 35 lungs displayed the typical gross appearance of chronic bronchopneumonia, with several or all of the characteristic histological features. M. ovipneumoniae was detected in 83% of the 35 lungs and Mannheimia haemolytica was isolated in 71%. Pneumonia associated with M. ovipneumoniae could be correlated to specific gross lesions consistent with the gross description of chronic bronchopneumonia in lambs.

Conclusion

In this study, chronic bronchopneumonia was the most common lung disease in routinely slaughtered Swedish lambs. This diagnosis was based on the characteristic macroscopic and histopathologic pulmonary findings and the frequent presence of the bacterium M. ovipneumoniae. The macroscopic appearance of chronic bronchopneumonia could therefore be used during routine investigation of the lamb carcasses at slaughter, to determine the most likely cause of pneumonia.

Molecular characterization of ureaplasmas isolated from reproductive tract of goats and sheep from Brazil

Ovine/caprine ureaplasmas have not yet been assigned a species designation, but they have been classified into nine serotypes. Herein ureaplasmas were searched for in 120 samples of vulvo vaginal mucous from sheep and 98 samples from goats at 17 farms. In addition, semen samples were collected from 11 sheep and 23 goats. The recovered ureaplasma were from sheep and goats from animals without any reproductive disorder symptoms, but not all animals presented positive cultures. In sheep, 17 (68%) cultures of vulvovaginal mucous were positive for ureaplasma and 11 (27%) samples of semen presented positive cultures in animals with clinical signs of orchitis, balanoposthitis or low sperm motility. In goats four ureaplasma isolates were obtained from vulvovaginal mucus, but the semen samples were all negative. The isolates were submitted to Pulsed-field gel electrophoresis methodology and their 16S rRNA genes were sequenced. Fifty percent of ureaplasma recovered from sheep allowed for PFGE typing. Eleven isolates showed eight profiles genetically close to the bovine ureaplasmas. The 16S rRNA gene sequencing showed differences or similarities of isolates from sheep and goats, and the reference strains of bovine and human ureaplasma. Four clinical isolates from sheep were grouped separately. The studied ureaplasma isolates showed to be a diverse group of mollicutes.

Advances in diagnosis of respiratory diseases of small ruminants

Irrespective of aetiology, infectious respiratory diseases of sheep and goats contribute to 5.6 percent of the total diseases of small ruminants. These infectious respiratory disorders are divided into two groups: the diseases of upper respiratory tract, namely, nasal myiasis and enzootic nasal tumors, and diseases of lower respiratory tract, namely, peste des petits ruminants (PPR), parainfluenza, Pasteurellosis, Ovine progressive pneumonia, mycoplasmosis, caprine arthritis encephalitis virus, caseous lymphadenitis, verminous pneumonia, and many others. Depending upon aetiology, many of them are acute and fatal in nature. Early, rapid, and specific diagnosis of such diseases holds great importance to reduce the losses. The advanced enzyme-linked immunosorbent assays (ELISAs) for the detection of antigen as well as antibodies directly from the samples and molecular diagnostic assays along with microsatellites comprehensively assist in diagnosis as well as treatment and epidemiological studies. The present review discusses the advancements made in the diagnosis of common infectious respiratory diseases of sheep and goats. It would update the knowledge and help in adapting and implementing appropriate, timely, and confirmatory diagnostic procedures. Moreover, it would assist in designing appropriate prevention protocols and devising suitable control strategies to overcome respiratory diseases and alleviate the economic losses.

A Review of Hypothesized Determinants Associated with Bighorn Sheep (Ovis canadensis) Die-Offs

Multiple determinants have been hypothesized to cause or favor disease outbreaks among free-ranging bighorn sheep (Ovis canadensis) populations. This paper considered direct and indirect causes of mortality, as well as potential interactions among proposed environmental, host, and agent determinants of disease. A clear, invariant relationship between a single agent and field outbreaks has not yet been documented, in part due to methodological limitations and practical challenges associated with developing rigorous study designs. Therefore, although there is a need to develop predictive models for outbreaks and validated mitigation strategies, uncertainty remains as to whether outbreaks are due to endemic or recently introduced agents. Consequently, absence of established and universal explanations for outbreaks contributes to conflict among wildlife and livestock stakeholders over land use and management practices. This example illustrates the challenge of developing comprehensive models for understanding and managing wildlife diseases in complex biological and sociological environments.

Shared Bacterial and Viral Respiratory Agents in Bighorn Sheep (Ovis canadensis), Domestic Sheep (Ovis aries), and Goats (Capra hircus) in Montana

Transmission of infectious agents from livestock reservoirs has been hypothesized to cause respiratory disease outbreaks in bighorn sheep (Ovis canadensis), and land management policies intended to limit this transmission have proven controversial. This cross-sectional study compares the infectious agents present in multiple populations of bighorn sheep near to and distant from their interface with domestic sheep (O. aries) and domestic goat (Capra hircus) and provides critical baseline information needed for interpretations of cross-species transmission risks. Bighorn sheep and livestock shared exposure to Pasteurellaceae, viral, and endoparasite agents. In contrast, although the impact is uncertain, Mycoplasma sp. was isolated from livestock but not bighorn sheep. These results may be the result of historic cross-species transmission of agents that has resulted in a mosaic of endemic and exotic agents. Future work using longitudinal and multiple population comparisons is needed to rigorously establish the risk of outbreaks from cross-species transmission of infectious agents.

Innate Immune Response to Intramammary Mycoplasma bovis Infection

The objective of the current study was to characterize the systemic and local innate immune response of dairy cows to IMI with Mycoplasma bovis, a pathogen of growing concern to the dairy industry. Ten Holstein cows were each infused in 1 quarter with M. bovis and studied for a 10-d period. Acute phase protein synthesis, which reflects 1 parameter of the systemic response to infection, was induced within 108 h of infection, as evidenced by increased circulating concentrations of lipopolysaccharide binding protein and serum amyloid A. Transient neutropenia was observed from 84 to 168 h postinfection, whereas a constant state of lymphopenia and thrombocytopenia was observed from 84 h until the end of the study. Milk somatic cell counts initially increased within 66 h of M. bovis infusion and remained elevated, relative to control (time 0) concentrations, for the remainder of study. Increased milk concentrations of BSA, which reflect increased permeability of the mammary epithelial-endothelial barrier, were evident within 78 h of infection and were sustained from 90 h until the end of the study. Milk concentrations of several cytokines, including IFN-gamma, IL-1beta, IL-10, IL-12, tumor growth factor-alpha, and tumor necrosis factor-alpha, were elevated in response to infection over a period of several days, whereas increases in milk IL-8 were of a more limited duration. Complement activation, reflected by increased milk concentrations of complement factor 5a, was also observed over several days. Despite the indication by these observed changes that the cows mounted a prolonged inflammatory response to M. bovis intramammary infection, all quarters remained infected throughout the study with persistently high concentrations of this bacterium. Thus, a sustained inflammatory response is not sufficient to eradicate M. bovis from the mammary gland and may reflect the ongoing struggle of the host to clear this persistent pathogen.

Genital Lesions in an Outbreak of Caprine Contagious Agalactia Caused by Mycoplasma agalactiae and Mycoplasma putrefaciens

This paper reports on the genital lesions observed in adult male and female goats from a commercial flock in the Extremadura region of southwestern Spain, following an outbreak of contagious agalactia syndrome caused by Mycoplasma agalactiae and M. putrefaciens. Although both species were isolated from several organs, M. putrefaciens was the only agent isolated from the genital lesions reported here, characterized by desquamative salpingitis and cystic catarrhal metritis in females and by testicular degeneration in males. Mycoplasma putrefaciens was isolated from the testes of only one of the males examined.

Infection of two goatherds with Mycoplasma mycoides subsp. capri in Hungary, evidence of a possible faecal excretion

During epidemic outbreaks in two goatherds clinical symptoms and deaths occurred in five (14%) of the 3-week-old goat kids in farm A, and in six (33%) of those in farm B. In the latter farm, three female goats aborted before the clinical symptoms in the kids emerged. Mycoplasma could be isolated from both healthy and sick goat kids and from female goats, which had diseased kids or had aborted. Three goat kids (one from herd A and two from herd B) were sent for post-mortem examination. In all these cases septicaemia caused by Mycoplasma was diagnosed. Based on the bacteriological examination the Mycoplasma strains proved to be Mycoplasma mycoides subsp. capri (Mmc). This was confirmed by the PCR examination. Mmc was isolated from several locations including from the rectum of one healthy female goat, and from two diseased kids. In addition, bacteria were detected in the small intestine in two of the necropsied kids by bacteriological and/or immunohistochemical methods. The finding suggests that Mmc may be transmitted via faeces in goatherds, kept under conventional conditions.