What is behind phylogenetic analysis of hospital-, community- and livestock-associated methicillin-resistant Staphylococcus aureus?

Methicillin-resistant Staphylococcus aureus (MRSA) has been shown to be the predominant life-threatening pathogen in Egypt. MRSA is a major cause of severe healthcare-associated (HA) infections. During the last decades, the incidence of community-associated (CA) MRSA infections has a complex epidemiology arising from the circulation of different strains in the general population. Moreover, livestock-associated (LA) MRSA emerged recently becomes an emerging threat to public health. Therefore, it is important to illuminate the differences between CA-, HA- and LA-MRSA to shed light on their genetic diversity and evolution. This study presents the first data on analysing the correlation between CA-, LA- and HA-MRSA using antibiogram typing, molecular characteristics and antimicrobial resistance and virulence genes' profiles. Overall, HA-MRSA strains tended to be multidrug resistant and less virulent than both LA- and CA-MRSA strains. Importantly, CA-MRSA strains had a high homology with each of HA- and LA-MRSA. However, no similarity was observed between HA- and LA-MRSA. Our findings suggest that the epidemiological changes in genetic behaviour between HA- and LA-MRSA are due to the presence of CA-MRSA confirming that CA-MRSA has created a public health crisis worldwide.

A study of morphological aspects of cystic echinococcosis in sheep in Sardinia.

We have investigated the morphological and structural aspects of hydatid cysts recovered from sheep raised in southern Sardinia during two surveys conducted over the 20 years since the last control attempt at the end of the 1980s. In the first study carried out during 1995-1997, a few years after the last control attempt, a total of 10,334 cysts were examined, recovered from 1029 infected sheep out of a total of 1375 inspected (prevalence 74.84%). In the second survey, conducted ten years later during the period 2005-2010 in the absence of specific control measures, a total of 6249 cysts were recovered from 916 parasitized sheep out of the 1414 examined (prevalence 64.78%). Cysts were grouped into 5 different types: "Unilocular", "Multisepted", "Calcified", "Caseous", "Hyperlaminated". Unilocular: fertile, consist of a single fluid-filled cavity; multisepted: generally sterile, fluid filled, with cavity divided into spheroidal chambers (3-dozen); calcified: sterile, small, with internal chambers almost virtual due to the thickening of internal septa; caseous: sterile, the cavity filled with a thick yellowish matrix; hyperlaminated: sterile, with a virtual cavity filled with extensively folded and overlapping sheets of hyperproduced laminated tissue. A thorough knowledge and the precise characterization of each type of lesion, making it possible to establish detailed parameters for cyst classification, appears very useful for the harmonization of data collection. From a surveillance and control perspective it is proposed that, in addition to other relevant epidemiological information, data from meat inspection be further improved, including morpho-functional indications about cyst type.

High-resolution differentiation of transmissible spongiform encephalopathy strains by quantitative N-terminal amino acid profiling (N-TAAP) of PK-digested abnormal prion protein.

New forms of transmissible spongiform encephalopathy (TSE) continue to be identified, and consequently sensitive differential diagnosis is increasingly important both for the management of disease in humans and livestock and in providing confidence in the safety of the food chain. TSE diseases are associated with accumulation of protease-resistant prion protein (PrP(Sc)) and detection of this marker protein is central to diagnosis. Proteolysis by proteinase K (PK) generates protease-resistant products (PrP(res)) with partially variable N-termini. The conformation(s) of PrP(Sc) and thus the points of PK cleavage are thought to be dependent on the strain of prion disease. Western blot (WB) analysis of PrP(res) gives characteristic migration patterns that can be used to diagnose TSEs, but the relatively low resolution of this technique limits its ability to differentiate certain disease strains. Mass spectrometry (MS) has the capability to resolve these various PK cleavage sites to the level of individual amino acid residues. In the present study multiple selected reaction monitoring (mSRM) was used to detect and quantify PrP(res) N-terminal tryptic peptides by MS and thus to define the N-terminal amino acid profiles (N-TAAPs) of PrP(res) characteristic for various TSEs in sheep. The fragmentation behaviour of the N-terminal tryptic peptides was studied to allow selection of the transitions specific for each peptide. Different PrP(res) preparation methods were evaluated and the most effective approach applied to differentiate the N-TAAPs corresponding to various sheep TSE isolates. Marked differences were identified between the N-TAAPs of bovine spongiform encephalopathy (BSE) and classical scrapie, and between classical scrapie and the experimental strains SSBP/1 and CH1641, thereby validating this approach as a means of TSE-strain specific diagnosis.

Differences in susceptibility to Mannheimia haemolytica-associated mastitis between two breeds of dairy sheep.

We used a Mannheimia haemolytica isolate to study differences in susceptibility to experimental mastitis between two breeds of dairy sheep. The isolate was deposited into the teat duct of Karagouniko (K, n=8) or Frisarta (F, n=8) ewes. The animals were monitored by means of clinical, bacteriological, cytological and pathological methods. K ewes did not develop any systemic or mammary clinical signs, whilst F ewes became ill and developed acute clinical mastitis 12 h later (P<0.001). Bacteria were isolated from 34/48 samples from K ewes and from 46/46 samples from F ewes. Positive California mastitis test (CMT) results were 17/24 samples from K ewes and 23/23 samples from F ewes; leucocytes were seen in Giemsa-stained films. Total pathology score summed over all group K ewes was 41 (maximum possible: 128); Man. haemolytica was isolated from 12/24 tissue samples. Total pathology score summed over all group F ewes was 93; Man. haemolytica was isolated from 24/24 tissue samples. Hyperplastic lymphoid nodules consisting of lymphocytes and plasma cells with germinal activity were characteristically present at the border between teat duct-teat cistern of group K ewes; no such structures were observed in teats of group F ewes. The results identified differences in susceptibility/resistance to a mastitis pathogen among animals of the two breeds. Defence mechanisms of the teat appeared to be inadequate against the invading organisms; as lymphoid nodules have been considered important defensive mechanisms of the ovine teat, their observed lack in Frisarta ewes might have predisposed them to development of mastitis.

[Tick-borne rickettsioses of domestic ruminants: taxonomic elements and laboratory diagnosis]. / Les rickettsioses des ruminants domestiques transmises par les tiques: elements taxonomiques et diagnostic de laboratoire.

Tick-borne rickettsioses are diseases which remain comparatively unknown to field veterinarians. The authors present a literature review, focusing on taxonomic aspects and on laboratory diagnosis.

A spirochete isolated from a case of severe virulent ovine foot disease is closely related to a Treponeme isolated from human periodontitis and bovine digital dermatitis.

The isolation of spirochetes from severe ovine foot disease has been reported recently by our research group. In this study we describe the preliminary classification of this spirochete based on nucleotide sequence analysis of the PCR-amplified 16S rRNA gene. Phylogenetic analysis of this sequence in comparison with other previously reported 16S rRNA gene sequences showed that the spirochete belonged to the treponemal phylotype Treponema vincentii which has been associated with bovine digital dermatitis and human periodontal disease. Further work is required to define the common virulence determinants of these closely related treponemes in the aetiology of these tissue destructive diseases.

Phylogenetic analysis by rRNA comparison of the highly pathogenic sheep-infecting parasites Theileria lestoquardi and a Theileria species identified in China.

In the Northwestern part of China there have been reports of clinical cases in small ruminants of a haemoparasite with the characteristics of Theileria hirci (T. lestoquardi). However, some properties of this parasites argue against its classification as T. lestoquardi. In this paper, we present evidence that T. lestoquardi and the Chinese Theileria isolate are distinct parasite species. Phylogenetic analysis of determined nucleotide sequences of small subunit ribosomal RNA (srRNA) genes of T. lestoquardi and the Chinese Theileria parasite show that they belong to different clades within the phylogenetic tree of piroplasms. The srRNA sequence of the Chinese parasite was found to be most closely related to T. buffeli, which, with T. sergenti, belongs to an evolutionary lineage of non-lymphoproliferative Theileria species. On the other hand, it was clearly divergent to a lineage of lymphoproliferative Theileria species; T. annulata, T. parva, T. taurotragi, and T. lestoquardi, the latter being most closely related to T. annulata.

[Endoparasitic infections in sheep from the Swabian Alb]. / Ein Beitrag zur Kenntnis des Endoparasitenbefalls der Schafe auf der Schwäbischen Alb.

The endoparasite fauna of 59 slaughtered sheep (30 lambs, 29 ewes) from the Swabian Alb, Germany, was examined. One species of trematodes, 3 species of cestodes, 29 species of nematodes (23 species of gastro-intestinal and 6 species of lung nematodes), 1 species of arthropodes and 1 species of protozoa were recorded. All animals were infected with Dicrocoelium dentriticum as well as gastro-intestinal and lung nematodes, 45.8% with Moniezia spp., 15.3% with Cysticercus tenuicollis, 55.9% with Oestrus ovis and 11.9% with Sarcocystis gigantea. The most important gastro-intestinal nematodes were Ostertagia circumcincta and Cooperia curticei, which were recorded in all sheep, Ostertagia trifurcata and Chabertia ovine (98.3% each), Oesophagostumum venulosum (96.6%), Nematodirus filicollis (81.4% each), Ostertagia pinnata (78.0%), Trichuris ovis and Trichostrongylus colubriformis (76.3% each). The ewes harboured more abomasal and small intestinal nematodes (1819 and 3702) than the lambs (695 and 1730), which haboured more large intestinal nematodes (177) than those (56). The most often recorded lungworms were Cystocaulus ocreatus (74.6%) and Muellerius capillaris (72.9%), followed by Neostrongylus linearis (57.6%), Dictyocaulus filaria (50.8%), Protostrongylus brevispiculum (37.3%) and Protostrongylus rufescens (28.8%). The ewes carried higher lungworm burdens than the lambs.

Etiology and prophylaxis of helminthiasis in sheep in Burkina Faso.

Helminths of "Mossi" sheep from traditional livestock were investigated at three different seasons (humid, cold dry, and hot dry seasons) in the village of Donsin from the central land of Burkina Faso. Three prophylaxis plans using Fenbendazole were tested. Primary parasites identified were: Oesophagostomum sp., Trichostrongylus sp., and Haemonchus contortus. These parasites were noticed mainly during the rainy season with mean egg per gram (epg) numbers of 500 +/- 141.42 in August-September, at the end of the rainy season. At this same period, hematocrit (22%) and body weights (17 kg of live weight) (LW) were low. These values progressively increased to reach their highest levels (32% and 27 kg of LW respectively) in February. The prophylactic plan consisting of two treatments with oral drench of 5 mg/kg LW of Fenbendazole turned out to be the most efficacious and the most economical.

Genetic databases: online catalogues of inherited disorders.

Current information on inherited disorders in domestic animals is available on the internet: Online Mendelian inheritance in animals (OMIA) and Mendelian inheritance in sheep (MIS) are the two major sources of information. OMIA was created (and is maintained) by workers at the University of Sydney. MIS has been compiled by the Committee on Genetic Nomenclature of Sheep and Goats (COGNOSAG), an international group of geneticists. In the future, similar catalogues for other species (starting with goats and cattle) will be made available by COGNOSAG. Electronic access to this information is freely accessible on the world-wide web at http:/(/)www.angis.su.oz.au/Databases/BIRX/om ia (for OMIA), http:/(/)probe.nalusda.gov:8300/animal/omia.h tml (for OMIA in the United States of America) and at http:/(/)www.angis.org.au/Databases/BIRX/mis (for MIS).

Role of neonatal and maternal risk factors in the faecal soiling of lambs.

A total of 1300 lambs from eight spring-lambing flocks in the south west of England were studied from birth to approximately six months of age. Within the first week of life a number of variables were recorded including the lambs' birth weight, sex, faecal consistency, 48- to 72-hour immunoglobulin status and the condition score and extent of faecal soiling (dag score) of the ewe. Between two and six months of age the lambs were inspected every two weeks and their dag score was recorded. The relationship between neonatal and maternal factors and the risk of becoming faecally soiled later in life (defined as a dag score of 3 or more) was estimated by survival analysis techniques and proportional hazards modelling. There was a significant increase in the rate of faecal soiling of lambs that had experienced a period of watery diarrhoea during the neonatal period (adjusted hazard ratio 1.78, P = 0.01), and lambs that were born to ewes with a high dag score (adjusted hazard ratio 1.48, P = 0.004). The lamb's birth weight was negatively correlated and its age was positively correlated with the rate at which they became faecally soiled. The results are discussed with reference to the determinants of susceptibility to blowfly strike.

Description and classification of different types of lesion associated with natural paratuberculosis infection in sheep.

Paratuberculosis lesions in naturally infected sheep were classified histologically. Adult sheep (n = 166) culled for various reasons, from four flocks in which clinical cases of the disease had occurred, were studied. Eight-two sheep (49.4%) showed lesions that could be divided into three main categories. Type 1 lesions, found in 24.1% of these animals, consisted of small granulomata formed by macrophages and were located exclusively in the ileocaecal Peyer's patch. In type 2 lesions, found in 4.8% of the sheep, granulomata were also observed in the mucosa associated with Peyer's patches. Type 3 lesions were characterized by granulomata in areas of the mucosa associated with, and also distinct from, the Peyer's patches. Three subtypes of type 3 lesions were recognized. In subtype 3a, found in 4.2% of the sheep, multifocal granulomata appeared in different areas of the lamina propria; they were not apparently associated with lymphoid tissue, and neither did they modify the morphology of the affected areas. Subtype 3b, found in 13.9% of animals, consisted of large numbers of macrophages, widespread in the lamina propria; in subtype 3c (2.4% of sheep) lymphocytes were the main inflammatory cell, with some macrophages scattered amongst them. In subtypes 3a and b, villi were distended and the mucosa appeared thickened. Mycobacteria could be demonstrated in tissue sections from all the samples with subtype 3b lesions and in almost all of those with type 2 and 3a lesions; these organisms were absent or sparse, however, in type 1 and 3c lesions. Macroscopical lesions were clearly visible only in sheep with type 3b and 3c lesions. Mycobacterium paratuberculosis was cultured from all the animals with type 3 lesions, from 87.5% of those with type 2 lesions, and from 47.5% of those with type 1. Type 3b lesions resembled the "borderline-lepromatous" form of mycobacterial lesions, whereas type 3c lesions resembled the "borderline-tuberculoid" form. The relationship between intestinal lymphoid tissue and paratuberculosis lesions is discussed, and the diagnostic importance of histological examination of the ileocaecal valve emphasized.

Grading the lesions of ovine footrot.

Sixteen methods of grading the lesions of ovine footrot were assessed on the basis of the effect of the lesions on the humoral immune response of the host to a causative bacterium, Dichelobacter nodosus. Methods that allowed for qualitative and quantitative differences in lesion scores between sheep were the best predictors of host response, and methods that assessed the lesions in each of the eight digits were more efficient than methods that did not grade the digits within feet. Weighting the scores for lesions that involved underrunning of the keratin of the hoof provided the most powerful means of predicting host response. The correlations between host response and the more elaborate weighted scores were close to the highest possible among additive linear estimators. Total weighted footscore, which is the sum of the footscores of the four feet weighted for underrun lesions, is proposed as a simple and effective grading system for sheep with lesions of footrot. There was a significant association within sheep between the number of underrun feet and the severity of lesions in individual feet.

An immunological classification of ovine lymphomas.

Sporadic ovine lymphoma cells were identified as T or B lymphocytes with a T cell-specific antiserum or by detecting surface immunoglobulin. Lymphomas were classified as being of T or B cell origin if 60 per cent, or more, of the cells were of the respective type. Of 16 lymphomas, 6 were T cell and 6 were B cell derived. In one lymphoma more than 60 per cent of the cells were identified as both T and B cells. In the other 3 lymphomas neither T nor B cells reached this value; 2 of these had negligible T and B cell numbers and were classified as null cell lymphomas. A relationship was seen between the immunological and anatomical classifications of the lymphomas in that all the T cell lymphomas were of multicentric distribution while 4 of the 6 B cell neoplasms were confined to the alimentary tract and its associated lymphoid tissue. In contrast, there was no relationship between the immunological and histological classifications of the lymphomas.

Pathology of spontaneous and experimental infection of North American wild ruminants with Mycobacterium paratuberculosis.

Spontaneous paratuberculosis was studied in free-ranging and captive bighorn sheep (Ovis canadensis), and Rocky Mountain goats (Oreamnos americanus). Lesions of paratuberculosis in these species resembled the disease in domestic sheep and goats. Mycobacterium paratuberculosis cultured from bighorn sheep was used to orally infect bighorn x mouflon (Ovis musimon) hybrid sheep, elk (Cervus elaphus nelsoni), mule deer (Odocoileus hemionus), and white-tailed deer (Odocoileus virginianus). Clinical paratuberculosis developed only in mule deer and was characterized by poor growth and diarrhea. Gross lesions were mild in all species. Enlargement of mesenteric lymph nodes was mild to moderate; the wall of the distal small intestine was affected minimally. Focal to diffuse infiltrates of epithelioid macrophages and giant cells occurred in the cortex of mesenteric lymph nodes, around mesenteric lymphatics, and in the intestinal mucosa. Extraintestinal lymph nodes, spleen, liver, and lung were involved in some animals; focal necrosis and mineralization was present in all species but was severe and widespread in the cervids.

Cytochemical reactions in bovine and ovine lymphosarcoma.

Cytochemical reactions with a panel of special stains were explored in peripheral blood and lymph node cells of animals with the adult, calf, and thymic types of bovine lymphosarcoma as well as lymphosarcoma in sheep induced with the bovine leukosis virus. These results were compared with normal lymphoid cells. Cytochemical methods included Sudan black B, periodic acid-Schiff, acid phosphatase and three esterases. Cells from ovine lymphosarcomas and a thymic type of bovine lymphosarcoma were distinctively positive to the alpha naphthyl acetate esterase reaction. These cytochemical reactions which were obtained with standard cytochemical methods should aid in the characterization and classification of lymphoproliferative disorders in animals, especially when combined with immunologic surface markers.