Serological and molecular comparison of Mannheimia haemolytica and Pasteurella trehalosi strains isolated from wild and domestic ruminants in the French Alps

Serotyping and Seroprevalence of Mannheimia haemolytica, Pasteurella multocida, and Bibersteinia trehalosi and Assessment of Determinants of Ovine Pasteurellosis in West Amhara Sub-region, Ethiopia

A cross-sectional study was undertaken in four (4) districts of the West Amhara sub-region of Ethiopia with the aim of assessing the diversity and distribution of serotypes of Pasteurella species, their seroprevalence, and associated risk factors, and knowledge, attitude, and practice of farmers toward ovine pasteurellosis. A total of 600 sheep sera were collected using multistage cluster sampling. Each sample was examined for the presence of six (6) serotype-specific antibodies using an indirect haemagglutination test. We are reporting a higher seroprevalence of 90.17% (541/600) in which all seropositive animals were shown to have been co-infected with multiple serotypes. Individual serotype prevalence showed that serotype A7 has the highest prevalence of 77.83% followed by A2 (74.33%), T15 (64%), T4 (62%), PA (60%), and A1 (39.17%). In this study, being female [odds ratio (OR): 2.45, 95% CI (1.09–5.52), p = 0.031] and living in high altitude areas [OR: 20.29, 95% CI (2.54–161.95), p = 0.004] were found to be significantly associated with sero-positivity. A questionnaire survey (n = 384) employed in a face-to-face interview was used to assess the knowledge, attitude, and practice of farmers related to ovine pasteurellosis. Accordingly, the majority (72.4%) of respondents had an inadequate knowledge level of the disease. The proportion of farmers with a favorable attitude and good practices toward the disease was 50.26 and 77.6%, respectively. This study is highly indicative that ovine pasteurellosis is a ubiquitous disease in the study area challenging the sheep production sector. The existence of diverse serotypes reported to lack cross-protective immunity is likely to explain why the current vaccination practice with the mono-serotype Pasteurella multocida biotype A vaccine is not providing adequate protection against outbreaks of the disease. Prioritization of one or more serotypes for inclusion in a multivalent vaccine should be dictated by the abundance and distribution of a particular serotype, its clinical importance, and its resultant economic impact. Furthermore, training farmers on key aspects of the disease is vital in the implementation of effective disease management strategies through a participatory approach. Data from the remaining regions of the country could help realize the development of an effective vaccine that works best at the national level.

Capsular type diversity of Mannheimia haemolytica determined by multiplex real-time PCR and indirect hemagglutination in clinical isolates from cattle, sheep, and goats in Spain

This study compares the utility of a commercially available multiplex q-PCR assay for serotyping A1, A2, and A6 M. haemolytica serotypes with indirect hemagglutination, for determining the relative distribution of M. haemolytica capsular types associated with respiratory disorders in cattle, sheep, and goats. For the 129 isolates analyzed, both q-PCR and IHA assays exhibited nearly complete agreement for capsular types A1 (k = 0.965) and A2 (k = 0.888) and substantial agreement for A6 (k = 0.801). Despite the overall good performance of the commercial q-PCR, its effectiveness differed between the host origin of the isolates. The serotype was identified by q-PCR in 83.3 % of cattle, 77.8 % of goat, and 53.8 % of sheep isolates. Combining the results of both methods, A1 was the most prevalent in cattle and sheep (55.6 % and 22.25 %, respectively) but was not detected in goats, A2 was the most prevalent in goats (61.1 %) and the second most prevalent in cattle (16.7 %) and sheep (20.5 %). The prevalence of A6 was 7.4 %, 5.1 %, and 16.7 % in cattle, sheep, and goats, respectively. Other capsular types determined exclusively by IHA were A16 in cattle, A9 in goats, and A7, A8, A9, and A13 in sheep. Capsular type diversity was greater in sheep (H = 0.601) than in cattle (H = 0.408) and goat (H = 0.330) isolates. The commercial multiplex q-PCR is a valuable tool, alternative to IHA, for identifying isolates of capsular types A1, A2, and A6, the most frequent serotypes of M. haemolytica associated with respiratory disease in ruminants. However, when testing sheep isolates it should be complemented with immunological assays due to the wider range of serotypes implicated.

Molecular characterization of Mannheimia haemolytica associated with ovine and caprine pneumonic lung lesions

This study investigated via polymerase chain reaction (PCR) three main serotypes (A1, A2, and A6) and nine virulence-associated genes in 71 ovine and caprine Mannheimia haemolytica isolates obtained from lungs (n = 349) with pneumonic lesions from a slaughterhouse in Iran. The lung specimens were collected from sheep (n = 197) and goats (n = 152) between December 2018 and January 2020. A total of 71 M. haemolytica isolates were identified in sheep (37/197; 18.8%) and goat (34/152; 22.4%) pneumonic lungs. Serotypes A2 (30/71; 42.3%) and A6 (29/71; 40.9%) were the most frequently detected, whereas the A1 serotype was detected with a frequency of less than 10% (7/71; 9.9%) and five isolates remained unknown. The virulence genes lkt, pomA, and nanH were present in all the isolates. The detection rates for the remaining virulence-associated genes were: gcp (95.8%), lpsA (93%), fhaC (90%), irp (70.4%), hf (57.7%), and sodC (21%). The sodC gene was exclusively detected among A2 isolates (50%), while the irp gene was more prevalent among A2 isolates and the hf gene among A1 and A6 isolates. These data may be useful for the typing of isolates in epidemiological studies. This study provides information about the main serotypes and the prevalence of virulence-associated genes among M. haemolytica ovine and caprine isolates in Iran.

Goat pasteurellosis: serological analysis of circulating Pasteurella serotypes in Tanqua Aberegelle and Kola Tembien Districts, Northern Ethiopia

OBJECTIVES

A cross-sectional study was employed with the aim to explore the serological status of goats; we evaluated the presence of serum antibodies of the circulating serotypes of the genus Pasteurella. A total of 124 serum samples were collected from randomly selected goats and subsequently serotyped using indirect haemagglutination test.

RESULTS

In the current study, the overall prevalence of pasteurellosis in goats was 31.4%. Additionally, a total of eight serotypes of Pasteurella were serotyped. It is evident that 25% out of 124 sampled animals were found infected by four or more circulating serotypes and 6.4% animals were also found positive for all serotypes. Accordingly, the prevalence of Pasteurella multocida serotype A were 16.9%, Mannheimia haemolytica serotype A1 26.6%, M. haemolytica serotype A2 18.5%, M. haemolytica serotype A7 16.1%, Bibersteinia trehalosi serotype T3 20.9%, B. trehalosi serotype T4 21.7%, B. trehalosi serotype T10 27.4%, and B. trehalosi serotype T15 was 25.8%. Therefore, although there has been vaccination campaign with monovalent vaccine P. multocida type A, the diseases still exerts negative impacts through death of goats to smallholder farmers. Therefore, to control the disease the government should provide multivalent vaccine of the above serotypes.

Small ruminant pasteurellosis in Tigray region, Ethiopia: marked serotype diversity may affect vaccine efficacy

The aim of this study was to investigate the prevalentBibersteinia, MannheimiaandPasteurellaserotypes, risk factors and degree of serotype co-infections in sheep and goats in the Tigray region of Ethiopia. Serum was collected from 384 sheep and goats from the Tanqua-Abergelle district of Tigray region using cross-sectional random sampling. An indirect haemagglutination test was used for serotyping. Risk factors for infections were evaluated by logistic regression. Potential clustering of multiple serotypes within individual animals due to common risk factors was evaluated by redundancy analysis. Eight serotypes were identified: all studied animals were serologically positive for at least one serotype. Overall, 355 (92·45%) of the animals were infected by four or more serotypes. Of the five risk factors studied, peasant association (PA), animal species, age (serotype A1), and bodyweight (serotype T15) were significantly associated with infection, but sex was not significant. Only PA explained a significant proportion of the variation (adjustedR2= 0·16) in the serological responses. After the effect of PA was accounted for, T3 and T4; A7 andPasteurella multocidaA; and A7 and T10 were positively correlated for co-infection, while T4 and T10 were less likely to be found within the same animal. Diverse serotypes were circulating in the Tigray region and could be a challenge in selecting serotypes for vaccine.

Mannheimia haemolytica and Bibersteinia trehalosi Serotypes Isolated from Merino Breed Lambs in Extremadura (Southwestern Spain)

Pneumonia caused by Mannheimia haemolytica is an important disease in ruminants. Because of its economic significance, several methods have been developed to study the pathogenicity and epidemiology of M. haemolytica. In this study, bacterial isolates of M. haemolytica and Bibersteinia trehalosi identified from the lungs of sheep were serotyped by means of indirect haemagglutination. Of the 598 lungs studied, 34 isolates were identified and serotyped. In decreasing order, M. haemolytica serotypes were: not typable (50 %), A1 (17.65 %), A7 (11.76 %), A6 (5.88 %), and A12, A2, A5 and A9 (each representing 2.94 %). The only B. trehalosi serotype was T4 (2.94 %). Serotypes A1, A6 and A7 of M. haemolytica were the most commonly isolated from pneumonic sheep producing greater changes in the lungs and having important implications for sheep production.

Acute die-off of chamois (Rupicapra rupicapra) in the Eastern Austrian Alps due to bacterial bronchopneumonia with Pasteurellaceae

Monitoring circulating pathogens in wildlife populations is important in evaluating causes and sources of disease as well as understanding transmission between wild and domestic animals. In spring 2010, a sudden die-off in a chamois (Rupicapra rupicapra) population sharing habitat with livestock occurred in northeastern Austria. Nineteen animals were submitted for examination. Necropsy and pathohistologic and bacteriologic results yielded lesions associated with Pasteurellaceae species. Additional testing included enterobacterial repetitive intergenic consensus and random amplification of polymorphic DNA PCR analysis to evaluate the circulating strains. The isolated strains were most closely related to Mannheimia glucosida and Bibersteinia trehalosi. Reports of mass mortalities in chamois due to pneumonia have been reported previously in the northern Alpine area of Italy. To the authors' knowledge, this is the first report of acute mortality due to strains of Mannheimia and Bibersteinia in Austrian chamois.