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P S Craig

Publications and source records attributed to P S Craig.

At least 19 recordsLinked to original sources
PubMed2006

A molecular phylogeny of the genus Echinococcus inferred from complete mitochondrial genomes.

Taxonomic revision by molecular phylogeny is needed to categorize members of the genus Echinococcus (Cestoda: Taeniidae). We have reconstructed the phylogenetic relationships of E. oligarthrus, E. vogeli, E. multilocularis, E. shiquicus, E. equinus, E. ortleppi, E. granulosus sensu stricto and 3 genotypes of E. granulosus sensu lato (G6, G7 and G8) from their complete mitochondrial genomes. Maximum likelihood and partitioned Bayesian analyses using concatenated data sets of nucleotide and amino acid sequences depicted phylogenetic trees with the same topology. The 3 E. granulosus genotypes corresponding to the camel, pig, and cervid strains were monophyletic, and their high level of genetic similarity supported taxonomic species unification of these genotypes into E. canadensis. Sister species relationships were confirmed between E. ortleppi and E. canadensis, and between E. multilocularis and E. shiquicus, regardless of the analytical approach employed. The basal positions of the phylogenetic tree were occupied by the neotropical endemic species, E. oligarthrus and E. vogeli, whose definitive hosts are derived from carnivores that immigrated from North America after the formation of the Panamanian land bridge. Host-parasite co-evolution comparisons suggest that the ancestral homeland of Echinococcus was North America or Asia, depending on whether the ancestral definitive hosts were canids or felids.

Animals↗
PubMed2006

Screening for Echinococcus granulosus in dogs: Comparison between arecoline purgation, coproELISA and coproPCR with necropsy in pre-patent infections.

Echinococcus granulosus is an important zoonotic infection of dogs. The purpose of the present study assessed the performance of two laboratory diagnostic methods with arecoline purgation and necropsy in infected dogs. In total 65 dogs were successfully experimentally infected with protoscoleces of E. granulosus from ovine infection. At 14-34 days post-infection groups of dogs were purged with arecoline hydrobromide and then necropsied. Faecal samples were tested at weekly intervals by coproantigen ELISA and coproPCR. The necropsy infection rate with E. granulosus was 89.2 per cent. Only 43 per cent of dogs were successfully purged after one arecoline dose; this percentage increased to 76.9% for two doses of arecoline purgation. E. granulosus coproantigen was detected by coproELISA in 82.8% of faeces. The positive and negative predictive values for coproantigen ELISA were 96 and 44.4% respectively. E. granulosus DNA was detected in pre-patent faecal samples by coproPCR in 25.9% of dogs. These results indicate that coproELISA is more sensitive than arecoline purgation for the detection of pre-patent E. granulosus infection in dogs. CoproPCR detected E. granulosus DNA in dog faeces by 21 days post-infection before egg production.

Animals↗
PubMed2006

Genotyping of human cystic echinococcosis in Xinjiang, PR China.

The Xinjiang Uygur Autonomous Region, multi-ethnic province in northwestern China, is one of the most important foci of human cystic echinococcosis (CE) in the world. Two Echinococcus granulosus genotypes (G1 and G6) are known to infect the intermediate hosts in this area but, to date, the source of the human infection remains unclear. The current study aimed to genetically analyse 67 hydatid cysts removed from 47 CE patients for which epidemiological, clinical and serological data were also recorded. Mitochondrial cox 1 gene sequencing suggested that the E. granulosus G1 genotype is the major source of infection (45/47 CE patients). Nevertheless, for the first time in China, 2 patients were found with hydatid cysts of the G6 genotype. In addition, 45 E. granulosus gravid tapeworms, isolated from 13 dogs, were genotyped. The majority of adult worms (42/45) exhibited the G1 genotype, whereas 3 adult tapeworms with the G6 genotype were found in one dog, that also harboured E. granulosus tapeworms of the G1 genotype. This sympatric occurrence of G1 and G6 genotypes of E. granulosus, not only in the same area but also in the same definitive host, raises the interesting question of putative genetic recombination between these E. granulosus genotypes.

Adolescent↗
PubMed2006

[Mixed infection of Echinococcus granulosus and Echinococcus multilocularis in dog].

OBJECTIVE: To identify mixed infection of Echinococcus granulosus and E. multilocularis in a dog from Xinjiang. METHODS: Thirty dogs from the pasture area were dissected and over 10,000 Echinococcus adult worms were found from one dog. Morphological observation revealed possible mixed infection of the two Echinococcus species. Further identification was made by amplification of the target gene DNA fragment (mitochondrial 12S rRNA gene). RESULTS: The adult worms of E. granulosus showed a relatively longer and larger gravid proglottid, its genital pore situated near or below the middle-side of the segment. The uterus was in a sacculate shape with irregular branches and approximately over 200 - 800 eggs in it. Morphology of the adult worms of E. multilocularis was similar to E. granulosus, slightly smaller, consisting of 4 to 5 proglottids. The uterus was not sacculate and with no branch. Its lateral genital pore often situated in the anterior part of the segment. Sequence analysis of mitochondrial 12S rRNA gene showed that amplification with the Eg1f/r primers shared complete identity with E. granulosus G1 genotype (GenBank accession no. AY462129), while that witht the EmH15/17 primers shared complete identity with E. multilocularis (GenBank accession no. AB031351). The presence of both E. granulosus and E. multilocularis was confirmed by microscopy and gene identification. CONCLUSION: Mixed infection of the two species of Echinococcus has been confirmed in the dog by morphological observation and PCR technique.

Animals↗
PubMed2006

Control of cystic echinococcosis/hydatidosis: 1863-2002.

Echinococcosis/hydatidosis, caused by Echinococcus granulosus, is a chronic and debilitating zoonotic larval cestode infection in humans, which is principally transmitted between dogs and domestic livestock, particularly sheep. Human hydatid disease occurs in almost all pastoral communities and rangeland areas of the underdeveloped and developed world. Control programmes against hydatidosis have been implemented in several endemic countries, states, provinces, districts or regions to reduce or eliminate cystic echinococcosis (CE) as a public health problem. This review assesses the impact of 13 of the hydatid control programmes implemented, since the first was introduced in Iceland in 1863. Five island-based control programmes (Iceland, New Zealand, Tasmania, Falklands and Cyprus) resulted, over various intervention periods (from <15 to >50 years), in successful control of transmission as evidenced by major reduction in incidence rates of human CE, and prevalence levels in sheep and dogs. By 2002, two countries, Iceland and New Zealand, and one island-state, Tasmania, had already declared that hydatid disease had been eliminated from their territories. Other hydatid programmes implemented in South America (Argentina, Chile, Uruguay), in Europe (mid-Wales, Sardinia) and in East Africa (northwest Kenya), showed varying degrees of success, but some were considered as having failed. Reasons for the eventual success of certain hydatid control programmes and the problems encountered in others are analysed and discussed, and recommendations for likely optimal approaches considered. The application of new control tools, including use of a hydatid vaccine, are also considered.

Animals↗
PubMed2006

Taenia solium taeniasis and cysticercosis in three communities in north Vietnam.

OBJECTIVES: (1) To investigate the response to a serum antigen-detecting ELISA for cysticercosis and a stool coproantigen test for taeniasis in two rural communities (mountainous and coastal areas) and one group of (peri-)urban factory workers; and (2) to examine clinical features of human cysticercosis in northern Vietnam. METHODS: Villagers and factory workers and their families were informed and invited to participate in the study. Blood and faecal samples were collected from the participants and a simple questionnaire on taeniasis/cysticercosis completed. Serum was examined for the presence of circulating cysticercus antigen by a monoclonal-based sandwich ELISA. Ag-ELISA positive persons underwent a clinical examination and a computed tomography (CT) scan. Stool samples were examined microscopically for the presence of Taenia eggs and for copro-antigens. Tapeworms were identified following therapeutic expulsion using morphology and PCR-RFLP. RESULTS: Circulating cysticercus antigens, suggesting active infection, were detected in 5.3% (16/303), 0.6% (1/175) and 0.0% (0/229) of the sampled individuals from the mountainous, coastal and urban regions, respectively. Clinical examination and CT scan of the cysticercus antigen positive persons showed that active cysticercosis did not cause severe disease in most cases. Taenia copro-antigens were found in 0.3% (1/297), 1.8% (3/166) and 0.0% (0/228) of the stool samples from the mountainous, coastal and urban communities, respectively. Three tapeworms were expelled after treatment: two Taenia solium and one Taenia saginata. CONCLUSION: This survey points to a focal distribution of taeniasis/cysticercosis and suggests that human cysticercosis is rather acquired due to close contact with a T. solium carrier and self-infection, than through infection from the environment.

Adolescent↗
PubMed2006

Hospital and community surveys reveal the severe public health problem and socio-economic impact of human echinococcosis in Ningxia Hui Autonomous Region, China.

A comprehensive study of human echinococcosis (caused by Echinococcus granulosus or E. multilocularis), including assessment of hospital records, community surveys and patient follow-up, was conducted in Ningxia Hui Autonomous Region (NHAR), China. In contrast to hospital records that showed 96% of echinococcosis cases were caused by cystic echinococcosis (CE), 56% of cases detected in active community surveys were caused by alveolar echinococcosis (AE). The AE and CE cases co-existed frequently in the same village, even occurring in the same patient. A serious public health problem caused by echinococcosis was evident in southern NHAR, typified by: a long diagnostic history for both AE and CE (7.5 years) compared with a shorter treatment history (4.7 years); a significant mortality rate (39%) caused by AE in one surveyed village, where patients had no previous access to treatment; family aggregation of CE and AE cases; a high proportion of both AE (62.5%) and CE (58%) in females; a high rate of recurrent surgery (30%) for CE demonstrated by surgical records; and frequent symptomatic recurrences (51%) because of discontinuous or sporadic access to chemotherapy for AE. The disease burden for both human AE and CE is thus very severe among these rural communities in NHAR, and this study provides the first attempt to determine the costs of morbidity and surgical intervention of human CE and AE cases both at the hospital and community level in this setting. This information may be useful for assessing the cost effectiveness of designing effective public health programs to control echinococcosis in this and other endemic areas in China and elsewhere.

Adolescent↗
PubMed2006

Canine echinococcosis in Turkana (north-western Kenya): a coproantigen survey in the previous hydatid-control area and an analysis of risk factors.

A study of Echinococcus granulosus infection in dogs, with risk-factor analysis, was carried out in the endemic area of northern Turkana district, Kenya, using necropsy on 42 strays and a coproantigen-ELISA survey of 161 owned animals. During the post-mortem examinations, 14 (33%) of the necropsied dogs were found infected with E. granulosus, with a mean burden of 540 worms (range=two to 4080 worms). The 26 necropsied dogs that came from the north-western Lokichoggio division--an area where, from 1983 to 1997, there had been a continuous programme of hydatid control--showed a similar prevalence of infection to the other dogs (34.6%) but a significantly lower mean burden, of 53 worms (range=two to 300). Forty-two (26%) of the animals tested for Echinococcus coproantigen were found positive. Although the dogs from the Lokichoggio division were more likely to be coproantigen-positive (29%) than those from the central Kakuma division (20%) or the north-eastern division (18%), the differences were not statistically significant. In questionnaire-based interviews, the owners of the dogs tested for coproantigens were asked about possible risk factors for canine infection with E. granulosus. Women were found to have twice the level of contact with dogs as men. The results of a univariate analysis of the dog-owners' responses revealed six factors that appeared to be significantly associated with a coproantigen-positive dog: non-restraint of the dog (P<0.001); dog fed on raw offal (P<0.001); the improper disposal of slaughter offal (P<0.001); the dog-owner's lack of knowledge about the transmission of echinococcosis (P=0.001); the dog not receiving anthelmintic treatment (P=0.003); and dog age < or =5 years (P=0.01). The results of a multivariate analysis confirmed that lack of dog restraint, access to raw offal, and young age of the dog (< or =5 years) each significantly increased the risk of coproantigen positivity (P, 0.005). Dogs that scavenged from cooking pots, were used to clean babies, had access to the inside of houses, and/or slept indoors appeared, however, to be at no increased risk of coproantigen positivity. The present results are discussed in relation both to older information on the epidemiology and role of human behaviour in the transmission of E. granulosus in Turkana, and the effects of the hydatid-control programme that ran continuously in the north-western division of Turkana between 1983 and 1997.

Animal Husbandry↗
PubMed2005

High prevalence of Taenia saginata taeniasis and status of Taenia solium cysticercosis in Bali, Indonesia, 2002-2004.

An epidemiological survey of taeniasis/cysticercosis was carried out in one semi-urban and two urban villages in three districts of Bali, Indonesia in 2002 and 2004. In total, 398 local people from 247 families were diagnosed by anamnesis and clinical examinations, and 60 residents were suspected to be taeniasis carriers. Among 60 suspected carriers, 56 persons expelled a total of 61 taeniid adult worms after praziquantel treatment. From 398 residents, 252 stool samples were available for analysis of taeniid eggs, coproantigens or copro-DNA for identification of taeniid species, and 311 serum samples were available for detection of antibodies against Taenia solium cysticercosis. Taeniasis prevalences were highly variable among three villages (1.1-27.5%), and only one case of cysticercosis due to T. solium infection was detected. All expelled tapeworms were confirmed to be Taenia saginata by mtDNA analysis. There was no Taenia asiatica human case in Bali. Case control analysis of 106 families chosen at random from 179 families in 2004 and another 106 families from non-endemic areas revealed that risk factors of T. saginata taeniasis for families were: level of education (P<0.01); consumption of beef lawar (P<0.01); and the source of lawar (P<0.01).

Adolescent↗
PubMed2005

Brain metastasis of alveolar echinococcosis in a hyperendemic focus of Echinococcus multilocularis infection.

An unusual female case, with alveolar echinococcosis (AE) disseminated from the primary hepatic lesion to the brain by metastasis formation, was retrospectively identified during a community survey in Ningxia Hui Autonomous Region, northwest China in 2003. Among possible metastases of hepatic AE, locations to the brain are rare and usually fatal; and they have especially been assigned to concomitant immune suppression. An enhancing role of pregnancy, which may be suspected in this case, the favourable outcome after surgery and chemotherapy, and also a mental disability in a child following long-term intrauterine exposure to mebendazole, make the report particularly unique.

Abnormalities, Drug-Induced↗
PubMed2005

Human cystic echinococcosis in two Mongolian communities in Hobukesar (China) and Bulgan (Mongolia).

In order to investigate the prevalence of human cystic echinococcosis (CE) in traditional Mongolian communities in western Mongolia and Xinjiang (northwest China), studies were carried out between 1995 and 2000, on two ethnically identical populations in Hobukesar (China) and Bulgan (Mongolia). The prevalence of human hepatic CE in the two communities was significantly different. In Hobukesar, human CE prevalence by ultrasound was 2.7% (49/1844), while in Bulgan it was 0.2% (4/1609) (P<0.001). Dog surveys showed that coproantigen-positive rates or dog necropsy positives were similar in both communities (35.0% in Hobukesar and 35.7% in Bulgan). Comparing possible risk factors, there appeared to be some significant differences between the two communities, which might contribute to the observed difference in CE prevalence. These included: the proportion of herdsman or farmers recorded; the proportions of dog ownership and livestock ownership; and the proportion of families practising home slaughter. The presence of a Russian dog-dosing programme up to the mid-1980s may explain the lower prevalence of human CE in the Bulgan population; no similar programme operated in the China-administered Hobukesar community.

Animals↗
PubMed2005

Helminth parasites of wolves (Canis lupus): a species list and an analysis of published prevalence studies in Nearctic and Palaearctic populations.

A literature survey was undertaken in order to draw up a definitive list of helminth parasites of the wolf, Canis lupus. From 27 papers a total of 72 helminth species from 40 genera were recorded that infect wolves, of which 93% were identified from the gastrointestinal tract at necropsy. They comprised 28 species of nematode, 27 species of cestode, 16 species of trematode and one acanthocephalan. Of these, 46 species were able to be included in further meta-analysis of prevalence data derived from 25 publications for which the total number of wolves examined was 1282 (1066 from Nearctic populations, and 216 from the Palaearctic region). These two populations were further subdivided into three relevent ecosystems or biomes, i.e. temperate/montane (n=216), boreal (n=805) or tundra (n=261). The meta-analysis of relative prevalence indicated the most common helminth species to be the tapeworm Taenia hydatigena, which occurred at relative rates of >30% for either zoogeographic region as well as in each of the three biomes. The related tapeworm, Echinococcus granulosus also exhibited high meta-prevalence (>19%) in all host biomes. The hookworm Uncinaria stenocephala was the most prevalent nematode species by meta-analysis (meta-prevalence 44.9%) in the temperate/montane biome, while the ascarid Toxascaris leonina was the dominant helminth species (meta-prevalence 73.9%) in the tundra wolf populations. Trematodes in the genus Alaria were the dominant fluke (meta-prevalence 3-5%) in all biomes. Analysis of published studies for helminth biodiversity using the Shannon-Wiener index based on species number and meta-prevalence by region or biome, indicated that highest helminth diversity occurred in wolf populations of the temperate/ montane biome (Palaearctic), and was lowest in tundra wolf populations of the Nearctic (P<0.05). Helminth species assemblage in European wolf populations was therefore at least as great or more varied than was recorded for the larger less disturbed wolf populations of North America.

Animals↗
PubMed2004

Serum sIL-2R, TNF-alpha and IFN-gamma in alveolar echinococcosis.

AIM: to approach the relationship between alveolar echinococcosis (AE) pathology and level of sIL-2R,TNF-alpha and IFN-gamma in sera and the significance of cytokines in development of AE. METHODS: After 23 patients with AE were confirmed by ELISA and ultrasound, their sera were collected and the concentrations of sIL-2R,TNF-alpha and IFN-gamma were detected by double antibody sandwich. Twelve healthy adults served as controls. According to the status of livers of AE patients by ultrasound scanning, they were divided into 4 groups: P(2), P(3), P(4) groups and C group (control). Average of concentrations of sIL-2R,TNF-alpha and IFN-gamma in homologous group was statistically analyzed by both ANOV and Newman-Keuls, respectively. RESULTS: The mean of sIL-2R in P(2) group was 97+/-29, P(3): 226+/-80, P(4): 194+/-23 and control group (111+/-30)X10(3) u/L (P<0.01). The mean of TNF-alpha in P(2) group was 1.12+/-0.20, P(3): 3.67+/-1.96, P(4): 1.30+/-0.25 and control group 0.40+/-0.19 mug/L (P<0.01). The mean of IFN-gamma in P(2) group was 360+/-20, P(3): 486+/-15, P(4): 259+/-19 and control group: 16+/-2 ng/L (P<0.01). Judged by ANOV and Newman-Keuls, the mean concentrations of sIL-2R, TNF-alpha and IFN-gamma had a significant difference among groups. Except for P(2) group, the mean sIL-2R between other groups of AE patients had a significant difference (P<0.05). The mean of TNF-alpha concentration in P(3) group was the highest (P<0.01). The mean of IFN-gamma concentration in all patients was higher than that in control group (P<0.01), but there was no difference between AE groups (P>0.05). CONCLUSION: Low sIL-2R level indicates an early stage of AE or stable status, per contra, a progression stage. Higher level of TNF-alpha might be related to the lesion of liver. The role of single IFN-gamma is limited in immunological defense against AE and it can not fully block pathological progression.

Adult↗
PubMed2004

Modelling the spatial distribution of Echinococcus multilocularis infection in foxes.

Alveolar echinococcosis is a rare but fatal disease in humans and is caused by the fox tapeworm Echinococcus multilocularis. The densities of fox and grassland rodent populations and the interactions between them influence E. multilocularis transmission rates in Europe. Successful rabies control has caused fox populations and E. multilocularis prevalence rates to increase in many European countries. The potential increase of the infection pressure on the human population motivates the monitoring of the infection status of foxes over space and time. Detection of E. multilocularis antigen levels in fox faecal samples collected in the field might provide a pragmatic methodology for epidemiological surveillance of the infection status in wildlife hosts across large areas, as well as providing an indication of the spatial distribution of infected faeces contaminating the environment. In this paper, a spatial analysis of antigen levels detected in faeces collected in the Franche-Comté region of eastern France is presented. In Franche-Comté, rodent outbreaks have been observed to originate in areas rich in grassland. Spatial trends in fox infection levels were modelled here as a function of the composition ratio of grassland in the landscape derived from the CORINE land-cover map. Kriging models incorporating the grassland trend term were compared to a variety of models in which five alternative trend expressions were used: the alternative trend expressions included linear and quadratic polynomials on the x and y coordinates with and without a grassland term, and a constant mean model. Leave-one-out cross-validation indicated that the estimation errors of kriging with a trend models were significantly lower when the trend expression contained the grassland index term only. The relationship between observed and predicted antigen levels was strongest when the estimated range of autocorrelation was within the home range size of a single fox. The over-dispersion of E. multilocularis in foxes may therefore account for the majority of spatial autocorrelation locally, while regional trends can be successfully modelled as a function of habitat availability for intermediate hosts.

Animals↗
PubMed2004

Ecological epidemiology: landscape metrics and human alveolar echinococossis.

The larval form of the fox tapeworm Echinococcus multilocularis can cause a potentially fatal liver infection in human hosts. Globally rare, the disease has a high prevalence focus in western China. Recent research has linked landscape to the presence and prevalence of the disease. This paper discusses the epidemiology of E. multilocularis in terms of landscape and disease transmission ecology. Landscape form was defined using satellite imagery to create a land cover classification for a study site in Zhang County (Gansu Province, China). Following the analysis of many landscape metrics, mean shape index was found to be related to the prevalence of infection for 31 villages in 1975 and 1997, at two spatial intervals, suggesting that habitat form is a correlate of disease. A temporal difference shows that the landscape is no longer suitable for transmission. These results indicate the possibility of identifying future hotspots which could aid the management of the disease.

China↗
PubMed2004

Echinococcus granulosus coproantigens: chromatographic fractionation and characterization.

Dogs infected with adult tapeworms of Echinococcus granulosus release antigens (coproantigens) in faeces which can be detected by a capture ELISA. Supernatants prepared from E. granulosus-infected dog faecal samples were fractionated by size-exclusion fast protein liquid chromatography (FPLC) on a Superose-6 column. Coproantigen ELISA and Western blotting were used to demonstrate the immunoreactivity of eluted fractions. Two main FPLC peaks of antigenic activity were detected and designated as fraction F1 and fraction F2 with approximate relative molecular weights > 670 kDa, and in the range of 146 to 440 kDa respectively. These two antigenic fractions (F1 and F2) fractionated from infected dog faeces were heat stable and largely protease-insensitive, but were highly sensitive to sodium periodate treatment, which strongly suggested the involvement of carbohydrates. Capture IgG antibodies against E. granulosus proglottis somatic extracts, detected a molecule with an approximate molecular weight of 155 kDa in fraction F2 after immunoblotting. The 155 kDa antigen could be completely ablated by sodium periodate treatment, but not after protease or lipase treatment. A surface tegument preparation of adult E. granulosus tapeworms contained large amounts of antigen that corresponded in size range and antigenicity to that observed in the FPLC fraction F2. There was also a peak of antigenic activity at > 670 kDa corresponding to fraction F1 from a culture derived excretory-secretory (E-S) adult tapeworm preparation. The involvement of carbohydrate moieties in coproantigen activity present in the FPLC fractions F1 and F2 from faecal supernatants of E. granulosus-infected dogs was confirmed by lectin-binding assays and exoglycosidase treatment, which showed that alpha-D-mannose and/or alpha-D-glucose, beta-galactose and N-acetyl-beta-glucosamine residues were the most important carbohydrate components in putative coproantigens present in both fractions. N-acetyl-beta-glucosamine and sialic acid residues were also contained in coproantigen molecules present in fraction F2. These results suggested that coproantigens detected in faeces of E. granulosus-infected dogs are large molecular weight molecules that may be derived from the carbohydrate-rich surface glycocalyx of adult worms, and are shed, released or secreted during the life-span of the tapeworm.

Animals↗
PubMed2004

A retrospective hospital study of human cystic echinococcosis in Egypt.

We performed a retrospective study to determine annual clinical incidence of human cystic echinococcosis (CE) in 14 Egyptian hospitals between January 1997 and December 1999. From 492 353 records examined, 133 (0.027%) new human CE cases were recorded. Of these, 50 (37.6%) were from Alexandria and Matrouh hospitals, 33 (24.8%) from Giza Chest Hospital and 50 from other regions. Matrouh governorate had the highest annual clinical incidence (1.34-2.60 per 100 000) followed by Giza governorate (0.80-1.16 per 100 000). About a third of those affected were aged < or = 20 years. Liver and lungs were the organs most affected. Although human CE is of low endemicity in Egypt, it may-represent a public health concern in Matrouh and Giza governorates.

Age Distribution↗