Epidemiology of nematode parasites of sheep around Jimma,southwestern Ethiopia

An investigation was made into the epidemiology of nematode infections of sheep in two districts of Jimma zone, southwestern Ethiopia. We used two approaches—long-term monitoring of identified sheep for nematode infection and abattoir or market survey for analysis. In the first monitoring regime, we used 80 lambs [40 sheep (20 per sex) from each district (Dedo and Yebu)] averaging 4–5 months of age. Faecal egg counts (FEC), packed cell volume (PCV) and body weight changes were monitored over a period of 1 year. Additionally, faecal samples were collected (on a weekly basis) from sheep brought to abattoir/market for 1 year to monitor faecal egg counts. The nematode parasite burden, as judged by FEC and PCV, was generally low indicating that the climatic conditions are not conducive to the development and survival of nematode eggs and the free-living stages; hence, little transmission occurred. In the experimental flocks, the highest FEC and lower PCV were recorded during the long rainy season (June to September) with peak in August and September. Faecal samples collected from abattoir/market also followed the same trend. Results from experimental sheep indicated that location had a significant (P < 0.01) effect on FEC, PCV and average daily body weight gain. The FEC and PCV for sheep in Yebu (mid-altitude) district were 126 ± 3.33 and 30.6 ± 0.26, whereas the values for Dedo (highland) were 93 ± 4.35 and 32.0 ± 0.21, respectively. The results indicate that the highland areas are comparatively less favourable to the survival and development of nematodes. Female lambs had lower FEC and higher PCV compared to male lambs (P < 0.05). The overall nematode parasite challenge in the area, however, is low. We, therefore, recommend rotational grazing management combined with monitoring parasite load and selective treatment to reduce productivity loses and pasture contamination.     

Species-specific PCR assay for the detection of Babesia odocoilei

We developed a PCR assay for the detection of Babesia odocoilei based on the 18S rRNA gene. Multiple specimens of B. odocoilei were examined, and the assay consistently produced a small specific PCR product of 306 bp. The PCR assay was also challenged with DNA from 13 other Babesia species and 2 Theileria species, originating from 10 different host species; however, nonspecific DNA amplification and multiple banding patterns were observed, and the amplicon banding patterns varied between different isolates of the same species. Sensitivity was determined to be 6.4 pg of DNA, and an estimated 0.0001% parasitism. This assay can be utilized for species-specific differential detection of B. odocoilei.     

Screening Wheat (Triticum spp.) Genotypes for Root Length under Contrasting Water Regimes: Potential Sources of Variability for Drought Resistance Breeding

Screening for root traits has been one of the most difficult areas to practise over large number of genotypes. Hydroponic systems enable easy access to roots while high‐molecular weight polyethylene glycol (PEG) is used to induce water stress. A total of 838 genotypes were evaluated for root length in a hydroponic trial under PEG‐induced stress and non‐stress growing conditions. Augmented complete block design with seven blocks and six standard control varieties was used. Root length differences were highly significant (P < 0.01) under both stress and non‐stress growing conditions among genotypes. Osmotic stress has caused an average reduction of 54 % in root length. Among the genotypes, root length ranged from 1.4 to 13.3 cm under stress, and 4.4 to 23.3 cm under non‐stress conditions, respectively. The best control variety for drought resistance was significantly (P < 0.05) outperformed by four new entries namely Colotana 296‐52, Compare, Santa Elena and Tammarin Rock, while the shortest roots were measured on genotypes Aus 16356, Elia, Camm, Portugal 3, and Sentinel. Differences among ploidy levels, domesticated and wild forms were also significant (P < 0.05). Hexaploid wheat showed significantly longer roots in both growing conditions while wild tetraploids showed the shortest roots under stress. There was a change in the ranking of genotypes under the two water regimes, which indicates the difficulty of selecting drought resistant varieties under optimum environments.     

Gastrointestinal Nematode Populations in Stabled Ewes of Rimouski Region

Nematode populations is stabled ewes of the Rimouski region were studied by means of fecal worm egg counts, fecal culture of larvae, and worm counts at necropsy. It was found that during the winter strongyle egg counts were low, Trichostrongylus eggs being most numerous, The stronglye egg counts increased following lambing and reached peak in June. Ostertagia spp was the principal contributor to this “spring-rise”, with substantial contribution from Trichostrongylus and Haemonchus contortus. The bulk of adult worm populations in winter, however, was made up of Trichostrongylus, whereas the great majority of the populations of Ostertagia spp, H. contortus and Nematodirus spp were inhibited in development at the fourth larval stage. All the worms recovered at necropsy in spring were adults, coinciding with the “spring-rise”.     

Serum antibody responses in horses and mice following immunization with Actinobacillus equuli outer membrane proteins and recombinant Aqx toxin

The immune responsiveness of mice (without prior natural exposure) and mares (with naturally acquired antibodies) was determined following vaccination with Actinobacillus equuli outer membrane proteins (OMPs) and/or recombinant A. equuli toxin (rAqx). Mice were vaccinated subcutaneously on days 0 and 21 with one of three doses (5, 25 or 50μg) of A. equuli OMPs, rAqx or both, together with Freund's incomplete adjuvant (FIA). Antibodies against formalin-killed whole bacterial cells (WBCs), OMPs and Aqx were determined on days 0, 21 and 42. Mares were vaccinated subcutaneously on days 0 and 21 with 100μg OMPs, 100μg rAqx or a combination of 50μg of each antigen, together with FIA. Antibodies against WBCs, OMPs and Aqx were determined at 7day intervals for the first 42days, as well as on days 56, 70, 154 and 238. Vaccination of mice stimulated an apparent dose response to OMPs and Aqx. Antibodies against OMPs and Aqx were enhanced following vaccination of mares that had naturally acquired pre-existing antibodies. There was no evidence of interference with antibody responses to the individual antigens when OMPs and rAqx were combined prior to vaccination.     

Farmers’ perceptions on trypanosomosis and trypanotolerance character of the taurine Sheko

In the humid and subhumid tropics, trypanosomosis is an economically important zoonotic protozoan disease of the commonly kept farm animal species and their wild relatives. For example, more than 20% of the humid western and southwestern Ethiopia, which is home to more than 14 million heads of cattle, is under varying levels of trypanosomosis risk. Our study was, therefore, initiated to document farmers’ perception on trypanosomosis and Sheko’s trypanotolerance character. Our findings showed that trypanosomosis was the most frequently reported cattle disease in the Bench Maji Zone. Accordingly, 76.7% of the farmers reported the epidemiological importance of trypanosomosis, and they also noted that trypanosomosis on average accounted for 63.0% of annualized cattle death. The reported signs of trypanosomosis and trypanotolerance indicators were consistent with literature reports. Moreover, 66.7% of the farmers reported Sheko’s trypanotolerance character. In the course of time, smallholder farmers have developed ethnoveterinary practices that are mainly used to prevent the landing of vector flies on the animal. Wet and warm seasons of the year, i.e., spring and, to some extent, the beginning of summer and autumn, were reported as peak periods of trypanosomosis risk. Therefore, this showed the need for incorporating farmers’ knowledge in trypanosomosis control programs.     

Proteomic analysis of purified turkey adenovirus 3 virions

Turkey adenovirus 3 (TAdV-3) causes high mortality and significant economic losses to the turkey industry. However, little is known about the molecular determinants required for viral replication and pathogenesis. Moreover, TAdV-3 does not grow well in cell culture, thus detailed structural studies of the infectious particle is particularly challenging. To develop a better understanding of virus-host interactions, we performed a comprehensive proteomic analysis of proteinase K treated purified TAdV-3 virions isolated from spleens of infected turkeys, by utilizing one-dimensional liquid chromatography mass spectrometry. Our analysis resulted in the identification of 13 viral proteins associated with TAdV-3 virions including a novel uncharacterized TaV3gp04 protein. Further, we detected 18 host proteins in purified virions, many of which are involved in cell-to cell spread, cytoskeleton dynamics and virus replication. Notably, seven of these host proteins have not yet been reported to be present in any other purified virus. In addition, five of these proteins are known antiviral host restriction factors. The availability of reagents allowed us to identify two cellular proteins (collagen alpha-1 (VI) chain and haemoglobin) in the purified TAdV-3 preparations. These results represent the first comprehensive proteomic profile of TAdV-3 and may provide information for illustrating TAdV-3 replication and pathogenesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-015-0214-z) contains supplementary material, which is available to authorized users.     

Response of Pasteurella haemolytica to erythromycin and dexamethasone in calves with established infection.

A subcutaneous soft tissue infection model in calves was used to study the in vivo response of Pasteurella haemolytica to erythromycin and dexamethasone. Two tissue chambers were implanted SC in each of 12 calves. At 45 days after implantation, all tissue chambers were inoculated with an erythromycin-sensitive strain of P haemolytica. Starting 24 hours after inoculation, calves were allotted to 4 groups of equal size and a 2 x 2-factorial arrangement of treatments was applied: 3 calves were given erythromycin (30 mg/kg of body weight, IM, for 5 days), 3 calves were given dexamethasone (0.05 mg/kg, IM, for 2 days), 3 calves were given erythromycin and dexamethasone, and the remaining calves served as nontreated controls. Chamber fluids were tested daily, and the response to treatment was measured. Neither erythromycin nor dexamethasone affected viability or growth of bacteria within tissue chambers. Dexamethasone had no effect on the influx of neutrophils into infected chambers. Despite repeated administration of a high dose of erythromycin and attainment of adequate concentration in serum, erythromycin concentration in chamber fluids did not exceed the minimal inhibitory concentration established in vitro. These results indicate that the clinical efficacy of erythromycin against P haemolytica sequestered in consolidated pneumonic lesions may not be well correlated with predictions based on serum pharmacokinetic and in vitro susceptibility data.     

A preliminary in vivo study on the potential application of e-tracking in poultry using ink printed 2D barcodes

A preliminary study on the potential application of electronic tracking in poultry in vivo has been conducted. The experimental procedure for this study was based on previous in vitro findings (Fröschle et al., 2009) as part of the same research programme. The study consisted of two phases whereby an initial experiment using inkjet printing of 10 × 10 DataMatrix barcodes onto the beaks of broiler chickens in a live commercial setting has been carried out. Results demonstrated very poor percentage of readability after a short period of time. Barcodes deteriorated very rapidly and this was attributed to the physical effects on the barcodes of the actions of the chickens in a commercial environment, together with the inability of the ink to bond to the hard keratinous surface of the beak. In a subsequent part of the study, a number of commercially available ink types were screened, using a predetermined abrasion testing procedure, for their ability to bond to the beak and provide a readable barcode on the beaks following some predetermined graduated physical abrasion.