Pseudotuberculosis in dromedary camels in the Canary Islands

Herd-level true seroprevalence of caseous lymphadenitis and paratuberculosis in the goat population of Poland

A large-scale study was carried out in the Polish goat population in 2014-2021 to determine the herd-level true seroprevalence (HTP) of caseous lymphadenitis (CLA) caused by Corynebacterium pseudotuberculosis (Cp) and paratuberculosis (PTB) caused by Mycobacterium avium ssp. paratuberculosis (Map). Two-stage cluster sampling was applied to herds counting at least 20 adult goats (aged >1 year) and in each herd all males and 10-13 females were tested. At least one seropositive goat regardless of its sex was necessary to consider the herd as infected. HTP was estimated using the Bayesian approach with the Gibbs sampler in the EpiTools and reported as the median and 95 % credibility interval (95 % CrI). A total of 1282 adult goats from 86 herds were serologically tested using two commercial ELISAs (Cp-ELISA and Map-ELISA). At least 1 seropositive result of Cp-ELISA and Map-ELISA was obtained in 73/86 herds (84.9 %) and 40/86 herds (46.5 %), respectively. HTP of CLA was estimated at 73.3 % (95 % CrI: 65.0 %, 80.4 %) and HTP of PTB was estimated at 42.9 % (95 % CrI: 25.8 %, 58.0 %). There was a significant positive association between the occurrence of CLA and PTB in the herds (odds ratio 6.0, 95 % confidence interval: 1.2, 28.8; p = 0.010). Probability of the seropositive result for PTB was also significantly higher in Cp-seropositive goats than in Cp-seronegative goats (odds ratio 3.9, 95 % confidence interval: 2.4, 6.3; p < 0.001) which could indicate either a higher risk of co-infection or a higher rate of false positive results for PTB in Cp-positive goats. To investigate this issue, optical densities obtained in Map-ELISA were compared between Cp-positive and Cp-negative goats and results of Map-ELISA were adjusted accordingly. Map-negative sera from Cp-positive goats turned out to have significantly higher optical densities than Map-negative sera from Cp-negative goats (p < 0.001). After the adjustment, the herd-level apparent seroprevalence of PTB was 41.9 % (36/86 herds) so it still fell within the 95 % CrI of HTP of PTB calculated before the adjustment. Concluding, CLA appears to be widespread in the Polish goat population. In many of them it may be subclinical at the moment, however will likely emerge in the future as the disease follows cyclic pattern in Poland. On the other hand, given the total lack of clinical PTB in Polish goats, an explanation for a high HTP of PTB remains unclear and warrants further studies using tests of higher analytical specificity than ELISA.

Pathology, bacteriology and molecular studies on caseous lymphadenitis in Camelus dromedarius in the Emirate of Abu Dhabi, UAE, 2015-2020

Caseous lymphadenitis (CLA) or pseudotuberculosis is a chronic zoonotic bacterial disease caused by Corynebacterium pseudotuberculosis, which affects livestock and humans. This study aimed to describe the pathology, bacteriology and confirm the identity of the pathogen by 16S rRNA gene sequencing in Camelus dromedarius. A total of 12 camels with suspected CLA in three regions of Abu Dhabi Emirate (Abu Dhabi, Al Ain and Al Dhafra), United Arab Emirate (UAE) were subjected to clinical and postmortem examinations from January 2015 to December 2020. Clinically, camels were emaciated and showed the presence of external caseous abscesses suggestive of CLA. Postmortem examination showed multiple abscesses of variable sizes with caseous material encapsulated by fibrous tissue in the liver, lungs, muscle, and lymph nodes. Following clinical and postmortem examination, blood, pus and different tissue samples were collected for subsequent analysis. Histopathological examination of all organs stained with Hematoxylin and Eosin (H&E) indicated a central caseo-necrotic core that was admixed with bacterial colonies and infiltration of chronic inflammatory cells, surrounded by a pyogenic membrane, and an outer fibrous connective tissue capsule. Bacterial culture identified the isolates of Corynebacterium pseudotuberculosis biotype ovis strain, and these isolates were shown to be sensitive to all antibiotics tested (penicillin, ampicillin, Co-trimoxazole, enrofloxacin and tetracycline). Moreover, the identity of the isolates was confirmed by partial sequencing of the 16S rRNA gene which showed a 100% identity to Corynebacterium pseudotuberculosis. Phylogenetic analysis based on 16S rRNA gene sequence clearly differentiates Corynebacterium pseudotuberculosis from other species of Corynebacterium. Briefly, this study provided the basic information for infection of Corynebacterium pseudotuberculosis in Camels and will help in controlling of this pathogen in the region.

Whole-genome sequence of Corynebacterium pseudotuberculosis strain Cp162, isolated from camel

Corynebacterium pseudotuberculosis is a pathogen of great veterinary and economic importance, since it affects livestock, mainly sheep and goats, worldwide, together with reports of its presence in camels in several Arabic, Asiatic, and East and West African countries, as well as Australia. In this article, we report the genome sequence of Corynebacterium pseudotuberculosis strain Cp162, collected from the external neck abscess of a camel in the United Kingdom.

Multiple abscesses caused by Salmonella enterica and Corynebacterium pseudotuberculosis in a dromedary camel

A rare case of arthritis, peri-arthiritis and pleurits associated with Salmonella enterica and Corynebacterium pseudotuberculosis infection in a dromedary camel is reported. Articular infections caused by Non-typhoidal Salmonella have been exceptionally described in human medicine. To our knowledge, this would be the first description of articular infections associated with Non-thyphoidal Salmonella in other mammals than humans. Possible pathogenesis of the infection is discussed.