PubMed Health⌕ Search

Biomedical subjects

A Mannelli

Publications and source records attributed to A Mannelli.

At least 19 recordsLinked to original sources
PubMed2005

Evaluation of an ELISA to detect antibodies to maedi-visna virus in individual and pooled samples of milk from sheep.

An elisa was used to detect antibodies to maedi-visna virus in samples of serum and milk from individual sheep; the results obtained indicated that the elisa can be used to detect antibodies in milk. The assay was also applied to samples of bulk-tank milk; a standard curve was created and used to calculate the seroprevalence of maedi-visna in 11 flocks of sheep and the results were compared with the results obtained by applying the elisa to individual serum samples. There was good agreement between the seroprevalences calculated from the standard curve for bulk-tank milk and from the individual serum samples.

Animals↗
PubMed2005

Analysis of the 1999-2000 highly pathogenic avian influenza (H7N1) epidemic in the main poultry-production area in northern Italy.

We evaluated the effects of risk factors and control policies following the highly pathogenic avian influenza (HPAI) epidemic that struck northern Italy's poultry industry in the winter of 1999-2000. The epidemic was caused by a type-A influenza virus of the H7N1 subtype, that originated from a low-pathogenic AI virus which spread among poultry farms in northeastern Italy in 1999 and eventually became virulent by mutation. Most infected premises (IP) were located in the regions of Lombardy and Veneto (382 out of 413, 92.5%), and the eradication measures provided for in the European legislation were enforced. In Veneto, where flock density was highest, infection-control was also accomplished by means of depopulation of susceptible flocks through a ban on restocking and pre-emptive slaughter of flocks that were in the vicinities of or that had dangerous contacts with IPs. In Lombardy, such control measures were applied to a lesser extent. Infection incidence rate (IR) was 2.6 cases per 1000 flocks per day in Lombardy and 1.1 in Veneto. After the implementation of infection-control measures, the at-risk population, the percentage of flocks < or =1.5 km from IPs, and the HPAI-IR underwent a greater reduction in Veneto than in Lombardy. Although the proximity (< or =1.5 km) to IPs in the temporal risk window (TRW) was a major risk factor for HPAI at the individual flock level, its effect at the population level (population-attributable fraction) did not exceed 31.3%. Viral transmission therefore also occurred among relatively distant flocks. Turkey flocks were characterised by greater IR of HPAI compared with other bird species such as layer hens, broilers, gamebirds, and waterfowl, even when located at distances >1.5 km from IPs. In Lombardy, IR for species other than turkeys was also relatively high.

Animals↗
PubMed2004

Development of recombinant capsid antigen/transmembrane epitope fusion proteins for serological diagnosis of animal lentivirus infections.

Among animal lentiviruses, Feline immunodeficiency virus (FIV), Equine infectious anaemia virus (EIAV) and Small ruminant lentiviruses (SRLV) are important pathogens associated with a variety of clinical pictures including immunodeficiency, anaemia, arthritis, pneumonia. The detection of viral antibody response represents a practical diagnostic approach in all lentivirus infections since they remain detectable long life. Capsid antigen (CA) is the major viral core protein and specific antibodies against this antigen are usually first recognised in infected sheep, goat and horse, remaining detectable for long period. Transmembrane (TM) domain of envelope glycoprotein contains a well conserved motif known to form an immunodominant epitope in several lentiviruses. In this study a simple strategy was developed to express the entire CA and the TM epitope in a single fusion protein from equine, feline and small ruminant lentiviruses in prokaryotic system and evaluated the diagnostic utility of a purified preparation in an indirect ELISA for each of the three infections. Results demonstrate that, for FIV and SRLV infections, the combination of CA and TM fractions increases the sensitivity of diagnostic tests based only on CA. The corresponding CA/TM antigen from EIAV showed excellent agreement with Coggins test.

Amino Acid Motifs↗
PubMed2003

Associations between dogs that were serologically positive for Rickettsia conorii relative to the residences of two human cases of Mediterranean spotted fever in Piemonte (Italy).

A geographic information system and K-function analysis were used to evaluate the spatial association of canine serological results for Rickettsia conorii, the causative agent of Mediterranean spotted fever (MSF), and clinical cases of MSF in humans in Piemonte, northwest Italy. The residences of dog owners were clustered in two rural villages in the province of Cuneo, where two human cases of MSF occurred in 1997 and 1998. Eighteen out of 116 dogs examined were positive by indirect immunofluorescent assay (IFA+, titre > or =1:160) for MSF. K-functions were compared for IFA+ dogs and for all dogs sampled. Monte Carlo and bootstrap simulations demonstrated that clustering of IFA+ dogs was significantly greater than clustering of all dogs, at distances of less than 0.6 km from human cases of MSF. Logistic regression analysis indicated that the risk of being IFA+ was highest for dogs residing within the first quartile of distance (0.7 km) from human cases of the disease, and for dogs that were not confined. However, year and season of blood collection were not associated with IFA status. It was concluded that a relatively high dog population density along with a rural or semi-rural environment favours the occurrence of emergent foci of MSF in the province of Cuneo.

Age Factors↗
PubMed2003

Acarological risk of exposure to agents of tick-borne zoonoses in the first recognized Italian focus of Lyme borreliosis.

Acarological risk was calculated as the probability of encountering at least one host-seeking Ixodes ricinus tick infected by the pathogen Borrelia burgdorferi sensu lato, in 100 m transects in the province of Genoa, Italy. The seasonal pattern of I. ricinus was studied using generalized estimating equations (GEE) with negative binomial error, to consider overdispersion of tick counts and repeated sampling of the same dragging sites from April 1998 to March 1999. Prevalence of infection by B. burgdorferi s.l. was evaluated by PCR and hybridization with genospecies-specific probes. Acarological risk (R) peaked in April (R = 0.2, 95% CI 0.13-0.26) and November (R = 0.29, 95% CI 0.10-0.46). Borrelia garinii and B. valaisiana were the most common genospecies at our study site suggesting a major role of birds as reservoirs. DNA from Anaplasma phagocytophilum, the agent of granulocytic ehrlichiosis in humans and animals, was amplified from an adult I. ricinus.

Anaplasma↗
PubMed2003

Prokaryotic expression and antigenic characterization of three recombinant Leishmania antigens for serological diagnosis of canine leishmaniasis.

Three recombinant antigens of Leishmania chagasi (= L. infantum) were expressed in prokaryotic systems and evaluated (using a panel of dog sera characterized by parasitological and serological immunofluorescent antibody test [IFAT] techniques) as diagnostic markers of infection. The whole open reading frame encoding K9, the gene fragment encoding the repetitive sequence of K26, and the 3'-terminal gene fragment encoding a single 39-amino-acid subunit of the kinesin-related protein K39 (K39sub) were amplified from L. infantum DNA and cloned into a pGEX-2T expression vector in frame with glutathione S-transferase (GST). The sensitivity and specificity of enzyme-linked immunosorbent assays (ELISAs) using K26 as an antigen (evaluated with sera from 20 parasitologically positive and 20 parasitologically negative dogs) were both 100% (95% confidence interval [CI] = 83.2 to 100). When K9 and K39sub were used, sensitivity was 95% (95% CI = 75.1 to 99.9) and specificity was 100% (95% CI = 83.2 to 100). Using 182 field sera, a good agreement was found between the recombinant K26 ELISA and IFAT (K = 0.92; 95% CI = 0.86 to 0.98) results and between the K9 and K39sub ELISA (used in parallel) and IFAT (K = 0.87; 95% CI = 0.80 to 0.95) results. The results demonstrate that each antigen carries immunodominant epitopes and that their combination may further increase the sensitivity of currently available serological tests.

Animals↗
PubMed2000

Expression and antigenic characterization of recombinant Mycoplasma agalactiae P48 major surface protein.

The gene encoding the P48 major surface lipoprotein of M. agalactiae has been recently characterised. Since its product plays an important role in the immune response of infected animals, in this study we analysed a recombinant P48 expressed in E. coli. Multiple point mutations were introduced by site directed mutagenesis in order to convert four tryptophan TGA codons, which are a typical feature of the mycoplasma genetic code, into the standard TGG. The mutated p48 gene was subcloned into pGex-2T and expressed in fusion with glutathione-S transferase. Following purification steps, P48 was eluted from carrier protein by thrombin digestion and used in Western blot and indirect ELISA using well-characterised sheep sera. Results demonstrate that specific antibodies against P48 are detected 3 weeks after onset of clinical disease and the recombinant P48 is a diagnostically relevant marker of M. agalactiae infection.

Animals↗
PubMed1999

Characterization of the immunodominant cross-reacting epitope of visna maedi virus and caprine arthritis-encephalitis virus capsid antigen.

Maedi visna (MV) and caprine arthritis-encephalitis (CAE) are two retroviral infections distributed world wide. Antigenic cross reactions between the viruses have been demonstrated in gag and env encoded structural proteins. Antigens from ovine lentiviruses are easier to produce in cell culture systems and therefore have been used in the development of diagnostic tests for both infections. Antigenically relevant epitopes have been characterised in the transmembrane protein, but little information is available on the immunodominant and cross reacting epitopes in the major capsid antigen (p25). In this study four different recombinant subunits of ovine lentivirus p25 were tested against sera from infected goats and a detailed characterisation of the immunodominant subunit was carried out. Highest ELISA absorbances were obtained with a 29 amino acid subunit located in the N'-terminal half of p25. Through the analysis of overlapping peptides spanning this region we identified a 17 amino acid sequence that can be used in the development of a highly standardized synthetic peptide-based assay.

Amino Acid Sequence↗
PubMed1999

Low risk of Lyme borreliosis in a protected area on the Tyrrhenian coast, in central Italy.

A comprehensive Lyme borreliosis risk assessment process was applied in S. Rossore Estate, on the Tyrrhenian coast, near Pisa, Italy. Host-seeking Ixodes ricinus nymphs peaked in May in oak-dominated deciduous wood (median, Q1-Q3, number of nymphs/50 m dragging = 4.5, 2.5-8), whereas host-seeking larvae peaked in August in the same habitat type (6.0, 4-17/50 m dragging). Prevalence of I. ricinus infestation was 88.9% in wild rodents (n = 11), 64.3% in fallow deer (n = 28) and 0.0% in wild boars (n = 5). Borrelia burgdorferi sensu lato was not isolated from rodents' organs, and from 80 I. ricinus nymphs and 50 adults. Moreover, PCR for B. burgdorferi sl carried out on 110 nymphs and 12 adult ticks also gave negative results. Forest workers were at higher risk of tick bite than other Estate employees (relative risk (RR): 1.7, p = 0.02). In spite of high levels of tick exposure, B. burgdorferi sl specific antibodies were not detected in sera from Estate personnel (n = 30) and sentinel animals (dogs, n = 23, fallow deer, n = 61).

Animals↗
PubMed1998

Temporal and spatial patterns of African swine fever in Sardinia.

Temporal patterns and spatial distribution of African swine fever (ASF) were studied through the analysis of routinely collected data in the ASF-endemic area of the Province of Nuoro, Sardinia. During 1993-1996, ASF outbreaks were reported from 45 out of the 82 municipalities of the study area. Overall farm-level incidence rate (IR) was 1.3 outbreaks per 100 farms-year. ASF peaked in 1995 (IR = 1.8) and declined in 1996 (IR = 0.82). Significant (P < 0.05) spring peaks of ASF outbreaks and affected municipalities were detected using statistical methods for circular distributions. Spatial clustering of ASF-affected municipalities, as evaluated by join-count statistics, was significant in 1993 (Zjc = -3.0, P < 0.01) and 1994 (Zjc = -3.2, P < 0.01) but not in 1995 (Zjc = -0.6, P = 0.55) and 1996 (Zjc = -1.2, P = 0.23). Extensive pig farming and ASF were spatially co-distributed (kappa = 0.51, 95% CI = 0.33-0.70).

African Swine Fever↗
PubMed1997

Effect of husbandry methods on seropositivity to African swine fever virus in Sardinian swine herds.

Multiple logistic regression was used on serological data collected in the context of the Sardinian African swine fever (ASF) eradication program from pig farms in the province of Nuoro, Sardinia. The monthly percentage of ASFV-positive herds decreased significantly from October 1994 through March 1996 (P < 0.001). The farm-level risk of seropositivity to African swine fever virus (ASFV) was higher in free-range farms than in partial-confinement farms (odds ratios (OR) varied between 4.9 in October 1994, and 5.7 in March 1996, P < 0.001). The risk of infection for total-confinement farms was one-fifth of the risk for partial-confinement farms in October 1994 (OR = 0.2, P < 0.001), whereas in March 1996, the estimated OR was 0.57 and not significant (upper confidence limit = 1.1). The maintenance of ASFV in Sardinia was primarily associated with free-range pig farms. The natural logarithm of the number of pigs tested per visit in a farm was positively associated with the risk of herd seropositivity (OR = 2.6, P < 0.001).

African Swine Fever↗
PubMed1997

Role of the eastern chipmunk (Tamias striatus) in the epizootiology of Lyme borreliosis in northwestern Illinois, USA.

The role of the eastern chipmunk (Tamias striatus) in the epizootiology of Lyme borreliosis was evaluated in Castle Rock State Park, Illinois (USA), an enzootic region, from June to August 1993. Prevalence, intensity, and molting rate of immature Ixodes scapularis were determined for chipmunks, white footed mice (Peromyscus leucopus), and raccoons (Procyon lotor). Chipmunks were the primary host for I. scapularis nymphs and an important secondary host for I. scapularis larvae. Based upon ear punch biopsy analysis, B. burgdorferi prevalence in chipmunks was similar to that of mice in August and greater than that of mice in June and July. Thus we propose that chipmunks are the primary source of B. burgdorferi infection for I. scapularis nymphs and an important secondary source of infection for larvae.

Animals↗
PubMed1997

Detection of Borrelia burgdorferi OspA in Ixodes scapularis larvae by an antigen-capture enzyme-linked immunosorbent assay.

The Borrelia burgdorferi outer surface protein A (OspA) was quantified by an antigen-capture ELISA. The test detected 0.156 ng OspA/B, using purified rabbit IgG as a detection system. Dose-response relationship was described by a three-parameter equation and second degree polynomials. The estimated amount of OspA in host-attached Ixodes scapularis larvae was positively correlated with the tick's engorgement status, whereas the presence of blood in OspA-negative larvae reduced test absorbance. The antigen-capture ELISA can be effectively used in the ecology and epidemiology of Lyme borreliosis. However, host attached larvae should be matched by engorgement level to remove the effect of this variable on test results.

Animals↗
PubMed1997

Spatial distribution and seasonality of ticks (Acarina: Ixodidae) in a protected area in the northern Apennines.

Infestation of small rodents by ixodid ticks and frequency of host-seeking ticks collected by dragging were studied at Orecchiella Natural Park (Northern Apennines) in 1994 and 1995. Levels of infestation of Apodemus spp. by immature Dermacentor marginatus were higher in beech wood (5.1 larvae and 1.3 nymphs per mouse) than in oak-chestnut wood and in coniferous wood. Larval D. marginatus peaked in mid summer, whereas nymphs peaked in late summer. Host-seeking Haemaphysalis punctata were mostly found on south-facing limestone rocks with scarce vegetation (7.8 larvae/km dragging). Conversely, D. marginatus larvae were most frequent in wooded areas (3.2 larvae/km dragging). Ixodes ricinus was rare in the Park, and Borrelia burgdorferi was not isolated from ear punches collected from 122 small rodents.

Animals↗
PubMed1995

Sources and reservoirs of Toxoplasma gondii infection on 47 swine farms in Illinois.

Field studies were conducted on 47 swine farms in Illinois during 1992 and 1993 to identify sources and reservoirs of Toxoplasma gondii infection. Blood samples were obtained from swine and from trapped wildlife. Serum antibodies to T. gondii were determined using the modified agglutination test, incorporating mercaptoethanol. Antibodies to T. gondii (titer > or = 25) were found in 97 of 4,252 (2.3%) finishing pigs, 395 of 2,617 (15.1%) sows, 267 of 391 (68.3%) cats, 126 of 188 (67.0%) raccoons, 7 of 18 (38.9%) skunks, 29 of 128 opossums (22.7%), 6 of 95 (6.3%) rats, 3 of 61 (4.9%) white-footed mice (Peromyscus sp.), and 26 of 1,243 (2.1%) house mice (Mus musculus). Brains and hearts of rodents trapped on the farm were bioassayed in mice for the presence of T. gondii. Toxoplasma gondii was recovered from tissues of 7 of 1,502 (0.5%) house mice, 2 of 67 (3.0%) white-footed mice, and 1 of 107 (0.9%) rats. Feces of 274 cats trapped on the farm and samples of feed, water, and soil were bioassayed in mice for the presence of T. gondii oocysts. Toxoplasma gondii was isolated from 2 of 491 (0.4%) feed samples, 1 of 79 (1.3%) soil samples, and 5 of 274 (1.8%) samples of cat feces. All mammalian species examined were reservoirs of T. gondii infection. All farms had evidence of T. gondii infection either by detection of antibodies in swine or other mammalian species, or by detection of oocysts, or by recovery from rodents by bioassay. The possibility of transmission of T. gondii to swine via consumption of rodents, feed, and soil was confirmed.

Animal Feed↗
PubMed1995

Risk factors for transmission of Toxoplasma gondii on swine farms in Illinois.

Two epidemiologic studies of risk factors for transmission of Toxoplasma gondii to swine were conducted for farms in Illinois. The first study was a cross-sectional survey of swine farms from the state of Illinois pseudorabies testing program, in which farm owners or managers were interviewed by telephone regarding presence of risk factors for transmission of T. gondii on the farm. There were 123 farms surveyed that provided blood samples for at least 30 sows. The mean sow seroprevalence was 19.5% (median = 10.0%). Multiple regression analysis of the association of sow seroprevalence with outdoor housing of sows, cat access to sow areas, number of sows, open feed storage and water delivery, delayed removal of carcasses, and presence of rodents on the farm indicated that higher sow seroprevalence was associated with cat access to sows (P = 0.009) and fewer sows in the herd (P = 0.05). The second study was a field investigation of 47 swine farms (37 from the cross-sectional study). Data collection included obtaining blood samples from swine, cats, and rodents, and fecal samples from cats, heart and brain tissue from rodents, and feed, water, and soil samples for T. gondii examination. The risk of T. gondii transmission from cats and rodents to sows and finishing pigs was evaluated, taking into account housing conditions and herd size. Multiple regression analysis indicated that T. gondii seroprevalence in finishing pigs increased with more seropositive juvenile cats on the farm (P < 0.0001) and higher seroprevalence in house mice (P = 0.0023).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗