First record of Marteilia sp. in mussels Mytilus galloprovincialis in Croatia

Marteiliosis is a disease of molluscs caused by Marteilia refringens in Europe and M. sydneyi in Australia. During routine examination of cultured mussels Mytilus galloprovinciallis in the northern Adriatic, the occurrence of Marteilia sp. was recorded with a prevalence of 5%. This parasite was not detected in flat oysters reared in the same area. The affiliation of the detected parasite in M. galloprovinciallis was confirmed by in situ hybridization using a M. refringens probe, specific at the genus level. DNA of these infected mussels originating from the same area will be used to clarify the taxonomic position of this species within the genus Marteilia using a molecular approach.     

Estimating prevalence and test accuracy in disease ecology: How Bayesian latent class analysis can boost or bias imperfect test results

1. Obtaining accurate estimates of disease prevalence is crucial for the monitoring and management of wildlife populations but can be difficult if different diagnostic tests yield conflicting results and if the accuracy of each diagnostic test is unknown. Bayesian latent class analysis (BLCA) modeling offers a potential solution, providing estimates of prevalence levels and diagnostic test accuracy under the realistic assumption that no diagnostic test is perfect.
2. In typical applications of this approach, the specificity of one test is fixed at or close to 100%, allowing the model to simultaneously estimate the sensitivity and specificity of all other tests, in addition to infection prevalence. In wildlife systems, a test with near‐perfect specificity is not always available, so we simulated data to investigate how decreasing this fixed specificity value affects the accuracy of model estimates.
3. We used simulations to explore how the trade‐off between diagnostic test specificity and sensitivity impacts prevalence estimates and found that directional biases depend on pathogen prevalence. Both the precision and accuracy of results depend on the sample size, the diagnostic tests used, and the true infection prevalence, so these factors should be considered when applying BLCA to estimate disease prevalence and diagnostic test accuracy in wildlife systems. A wildlife disease case study, focusing on leptospirosis in California sea lions, demonstrated the potential for Bayesian latent class methods to provide reliable estimates under real‐world conditions.
4. We delineate conditions under which BLCA improves upon the results from a single diagnostic across a range of prevalence levels and sample sizes, demonstrating when this method is preferable for disease ecologists working in a wide variety of pathogen systems.

     

Phylogenetic analysis of the small subunit ribosomal RNA of Marteilia refringens validates the existence of phylum Paramyxea (Desportes and Perkins, 1990)

Marteilia refringens is recognized as one of the most significant pathogens of bivalve molluscs. The nucleotide sequence of the small subunit ribosomal RNA gene of Marteilia refringens is used to elucidate the phylogenetic position of the phylum Paramyxea. Genomic DNA was extracted from sporangia of Marteilia, purified from infected blue mussels, Mytilus edulis, and flat oysters, Ostrea edulis. The sequences obtained from Marteilia species purified from both oysters and mussels were identical. The sequence identity was confirmed by in situ hybridization using a DNA probe targeted to a variable region of the ribosomal DNA. The small subunit ribosomal RNA gene sequence of M. refringens is very different from all known sequences of eukaryotic organisms, including those of myxosporeans and haplosporeans. Therefore, the phylum Paramyxea should continue to be recognized as an independent eukaryotic phylum.     

Estimating the true prevalence of Fasciola hepatica in cattle slaughtered in Switzerland in the absence of an absolute diagnostic test

A survey of 1,331 cattle presented for slaughter at two abattoirs in Switzerland was used to estimate the true prevalence of Fasciola hepatica infection and the diagnostic parameters of visual meat inspection, coproscopy after sedimentation technique, a commercial ELISA test for specific antibody detection in serum and the post mortem microscopic detection of eggs in bile. Faeces, blood and the gall bladder were taken from most cattle presented for slaughter. In addition, livers that were rejected by the meat inspectors were also dissected to examine for the presence of liver fluke. Bayesian techniques (Markov Chain-Monte Carlo) were used to estimate the diagnostic parameters of each of these procedures and the true prevalence of bovine fasciolosis. The true prevalence of F. hepatica infection was estimated at 18.0% (95% credible intervals 15.9-20.3%). The diagnostic sensitivity of coproscopy, bile examination, antibody ELISA and meat inspection were estimated at 69.0% (57.3-79.7%), 93.4% (88.0-97.5%), 91.7% (87.2-95.2%) and 63.2% (55.6-70.6%), respectively. The diagnostic specificity of the ELISA test was estimated at 93.7% (91.7-95.2%). These results demonstrate that the prevalence of bovine fasciolosis is higher than previously thought due to the low sensitivity of meat inspection. They also demonstrate that traditional coproscopy can be very efficient if there is repeated sampling, resulting in sensitivity of approximately 92%.     

A study of diagnostic methods for Marteilioides chungmuensis infections in the Pacific oyster Crassostrea gigas

The eggs of the Pacific oyster, Crassostraea gigas, become infertile when infected by the parasite Marteilioides chungmuensis. Histologically, M. chungmuensis infects the oyster oocyte cytoplasm, and the ovaries take on a "lumpy" appearance once infected, which lowers commercial value of the oyster. This has a negative economic impact on oyster farms in South Korea and Japan. In this study, we compared traditional diagnostic methods (histology) with two molecular-based methods (polymerase chain reaction [PCR] amplification and in situ hybridization [ISH]) to identify M. chungmuensis-infected oysters. The efficacy of PCR and ISH to identify M. chungmuensis-infected oysters was compared to that of routine histology in 100 oysters. Thirty infections were identified using PCR and 16 using histology, whereas 31 infections were identified using ISH. The ISH and PCR assays were more sensitive compared to using histology with standard epidemiological methods. We strongly recommend that early parasitic invasion should be monitored with PCR/ISH methodologies as a basis for developing effective diagnostic techniques to identify M. chungmuensis-infected oysters.     

True versus apparent malaria infection prevalence: the contribution of a Bayesian approach

Aims

To present a new approach for estimating the “true prevalence” of malaria and apply it to datasets from Peru, Vietnam, and Cambodia.

Methods

Bayesian models were developed for estimating both the malaria prevalence using different diagnostic tests (microscopy, PCR & ELISA), without the need of a gold standard, and the tests'' characteristics. Several sources of information, i.e. data, expert opinions and other sources of knowledge can be integrated into the model. This approach resulting in an optimal and harmonized estimate of malaria infection prevalence, with no conflict between the different sources of information, was tested on data from Peru, Vietnam and Cambodia.

Results

Malaria sero-prevalence was relatively low in all sites, with ELISA showing the highest estimates. The sensitivity of microscopy and ELISA were statistically lower in Vietnam than in the other sites. Similarly, the specificities of microscopy, ELISA and PCR were significantly lower in Vietnam than in the other sites. In Vietnam and Peru, microscopy was closer to the “true” estimate than the other 2 tests while as expected ELISA, with its lower specificity, usually overestimated the prevalence.

Conclusions

Bayesian methods are useful for analyzing prevalence results when no gold standard diagnostic test is available. Though some results are expected, e.g. PCR more sensitive than microscopy, a standardized and context-independent quantification of the diagnostic tests'' characteristics (sensitivity and specificity) and the underlying malaria prevalence may be useful for comparing different sites. Indeed, the use of a single diagnostic technique could strongly bias the prevalence estimation. This limitation can be circumvented by using a Bayesian framework taking into account the imperfect characteristics of the currently available diagnostic tests. As discussed in the paper, this approach may further support global malaria burden estimation initiatives.     

Epidemiology and Diagnosis of Helicobacter pylori Infection

Medline, PubMed and the Cochrane databases were searched on epidemiology and diagnosis of Helicobacter pylori for the period of April 2011-March 2012. Several studies have shown that the prevalence of H.?pylori infection is decreasing in adults and children in many countries. Various diagnostic tests are available, and most of them have high sensitivity and specificity. The Maastricht IV/Florence consensus report states that the urea breath test using (13) C urea remains the best test to diagnose H.?pylori infection. Among the stool antigen tests, the ELISA monoclonal antibody test is recommended. All these tests were used, either as a single diagnostic test or in combination, to investigate H.?pylori infection among different populations throughout the world. Of particular interest, current improvements in high-resolution endoscopic technologies enable increased diagnostic accuracy for the detection of H.?pylori infection, but none of these techniques, at present, are specific enough for obtaining a real-time diagnosis of H.?pylori infection.     

Bonamia exitiosa (Haplosporidia) observed infecting the European flat oyster Ostrea edulis cultured on the Spanish Mediterranean coast

Bonamia exitiosa and Bonamia ostreae are parasites that reproduce within the haemocytes of several oyster species. In Europe, the host species is the flat oyster Ostrea edulis. The parasite B. ostreae has been responsible for mortalities since the late 1970s throughout the European Atlantic coast. B. exitiosa was first detected, in 2007, on this continent in flat oysters cultured in Galicia (NW Spain). Since then, the parasite has also been detected in France, Italy and the United Kingdom. The bays of the Ebro Delta in the south of Catalonia represent the main bivalve culture area in the Mediterranean coast of Spain. Previous information from the area includes reports of several flat oyster pathogens, including the notifiable parasite Marteilia refringens. However, the status with regard to Bonamia parasites was uncertain. In the present study, a Bonamia parasite was observed in flat oysters cultured in the Alfacs Bay of the Ebro Delta by histology and real-time PCR. PCR-RFLP and sequencing suggested the presence of B. exitiosa. Finally, phylogenetic analyses of the studied Bonamia isolates corroborated B. exitiosa infection. M. refringens was also observed in the same oyster batch, and co-infection with both parasites was also detected. This is the first detection of B. exitiosa, in Catalonia and the Spanish Mediterranean coast. The impact of the parasite on the Mediterranean flat oyster activity needs to be urgently addressed.     

Southern blot and dot blot hybridisation compared to PCR for the detection of human papillomavirus DNA in biopsies of the uterine cervix from women with dysplasia

The aim of this study was to compare the sensitivity of Southern blot (SB) and dot blot (DB) hybridisation with polymerase chain reaction (PCR) for the detection of HPV in cervical biopsies from samples with differing histology. One hundred and forty seven women with cervical dysplasia had biopsies performed; one sample was analyzed for HPV DNA from types 6/11, 16, and 18 by SB, DB and PCR (L1 consensus primer and type specific probes) while an adjacent sample was examined histologically. The histology of the samples was normal in 40 (27%), squamous metaplasia in 25 (17%), inflammation 2 (1%) HPV infection 24 (17%), cervical intraepithelial neoplasia (CIN) grade I in 11 (7%), CIN II in 18 (12%), CIN III in 22 (15%), while 5 (3%) had invasive cancer. The number of biopsies positive for HPV DNA from types 6/11, 16, and 18, using the different hybridisation methods was 56 (38%) by dot blot, 57 (39%) by Southern blot hybridisation and 66 (45%) by PCR. When the L1 consensus primer was used 100 (68%) specimens were positive by PCR. The sensitivity of SB and DB hybridisation, as compared with PCR (type specific probes 6/11, 16, 18) was greater in biopsies with abnormal histology (histological grades of HPV infection and greater, as a group) (sensitivity of SB 83%, DB 74%) than those with normal and metaplastic change (as a group) (sensitivity of SB 44%, DB 35%) (P < 0.005 for SB and DB) (inflammation excluded from analysis). This study demonstrated that the sensitivity of SB and DB hybridisation, relative to PCR is greater in samples with abnormal histology than in samples with normal histology.     

Multi-test analysis and model-based estimation of the prevalence of Taenia saginata cysticercus infection in naturally infected dairy cows in the absence of a ‘gold standard’ reference test

The diagnostic values of seven serological tests (ELISAs) and of the obligatory European Union-approved routine visual meat inspection for the detection of Taenia saginata cysticercosis were investigated. A total of 793 slaughtered dairy cows were selected in three European Union approved abattoirs in Switzerland, an endemic area (apparent prevalence by enhanced meat inspection up to 4.5%) with typically low parasite burdens. ELISAs based on a somatic larval antigen, isoelectric focused somatic larval antigen, larval excretory/secretory antigens, peptide HP6-2, peptide Ts45S-10, pooled peptide solution and a monoclonal antibody antigen capture assay were initially screened. As there is no perfect diagnostic ‘gold standard’ reference test, the obligatory meat inspection and four selected serological tests were further analysed using Bayesian inference to estimate the “true” prevalence and the diagnostic test sensitivities and specificities. The ELISA for specific antibody detection based on excretory/secretory antigens showed highest sensitivity and specificity with 81.6% (95% credible interval: 70–92) and 96.3% (95% credible interval: 94–99), respectively. The Bayesian model estimated the specificity of the ELISA, based on the synthetic peptide Ts45S-10 as 55.2% (95% credible interval: 46–65) and sensitivity as 84.7% (95% credible interval: 82–88). The sensitivity of the ELISA based on mAbs, detecting circulating antigen, was 14.3% (95% credible interval: 9–23) with a specificity of 93.7% (95% credible interval: 92–96). The diagnostic sensitivity of the obligatory standard European Union meat inspection procedure for the detection of T. saginata cysticercus infection at the abattoir was estimated to be 15.6% (95% credible interval: 10–23). Based on these data, the modelled prevalence of cysticercosis in dairy cows presented at abattoirs in Switzerland was estimated to be 16.5% (95% credible interval: 13–21). These cattle also had a high prevalence of infection with Dicrocoelium dendriticum (60.8%) and Fasciola hepatica (13.5%).     

Detection of Minchinia sp., in rock oysters Saccostrea cuccullata (Born, 1778) using DNA probes

Haplosporidian parasites infect various invertebrate hosts including some commercially important shellfish. Haplosporidium nelsoni (along with Perkinsus marinus) has severely affected Eastern oyster production on the eastern seaboard of the United States and flat oyster production in Europe has been severely impacted by Bonamia ostreae. These parasites are also often present at a very low prevalence and there are a variety of morphologically similar species that can be difficult to differentiate during cytological or histological diagnosis hence the need to develop specific tests. Recently, a Minchinia sp. was described affecting rock oysters (Saccostrea cuccullata) in north Western Australia. In this study, two in situ hybridisation (ISH) assays and a PCR assay have been developed and optimised for use in investigating these parasites. The first ISH assay used a 166bp polynucleotide probe while the second used a 30bp oligonucleotide probe. The specificity of each ISH assay was assessed by applying each probe to a variety of haplosporidian (5), a paramyxian (1) or ciliophora (1) parasites. The polynucleotide probe produced strong hybridisation signals against all of the haplosporidian parasites tested (Minchinia sp., Minchinia teredinis, Bonamia roughleyi, H. nelsoni and Haplosporidium costale) while the oligonucleotide probe recognised only the Minchinia sp. Both probes failed to detect the paramyxian (Marteilia sp.) or the Rhynchodid-like ciliate. The PCR assay amplifies a 220bp region and detected Minchinia sp. DNA from 50ng of genomic DNA extracted from the tissues of infected oysters and 10fg of amplified Minchinia sp. DNA. The assay did not react to oysters infected with H. nelsoni or H. costale. The ability of the PCR and oligonucleotide ISH assay to diagnose Minchinia sp. infected oysters was compared to histological examination from a sample of 56 oysters. The PCR assay revealed 26 infections while histological examination detected 14 infections. The oligonucleotide ISH assay detected 29 infections. The oligonucleotide ISH and PCR assays were found to be significantly more sensitive than histology for detecting the parasite.     

Sensitivity of a digoxigenin-labelled DNA probe in detecting Mikrocytos mackini, causative agent of Denman Island disease (mikrocytosis), in oysters

The protistan parasite Mikrocytos mackini, causative agent of Denman Island disease (mikrocytosis), induces mortality and reduces marketability in the Pacific oyster, Crassostrea gigas, in British Columbia, Canada. This parasite is a pathogen of international concern because it infects a range of oyster species, and because its life cycle and mode of transmission are unknown. A digoxigenin-labelled DNA probe in situ hybridisation technique (DIG-ISH) was developed, and its detection sensitivity was compared to standard histological sections stained with haematoxylin and eosin stain (H&E-histo). In H&E-histo preparations, the detection of M. mackini was certain only when the parasite occurred within the vesicular connective tissue of adult oysters. However, the DIG-ISH technique clearly demonstrated the presence of infection in all other host tissues as well as in juvenile oysters with poorly developed vesicular connective tissue. The probe hybridised strongly to M. mackini, did not hybridise to oyster tissues or with the other shellfish parasites tested, and was more sensitive for detecting infections when compared to H&E-histo.     

Infection dynamics of Marteilia refringens in flat oyster Ostrea edulis and copepod Paracartia grani in a claire pond of Marennes-Oléron Bay

The protozoan parasite Marteilia refringens has been partly responsible for the severe decrease in the production of the European flat oyster Ostrea edulis Linnaeus in France since the 1970s. The calanoid copepod Paracartia grani Sars was recently found to be a host for M. refringens in French shallow-water oyster ponds ('claires'). This study reconsidered M. refringens transmission dynamics in the light of this finding, taking into account not only oyster infection dynamics and environmental factors but also data concerning the copepod host. P. grani population dynamics in the claire under study revealed that this species is the dominant planktonic copepod in this confined ecosystem. During winter, M. refringens overwintered in O. edulis, with P. grani existing only as resting eggs in the sediment. The increase in temperature in spring controlled and synchronized both the release of M. refringens sporangia in the oyster feces, and the hatching of the benthic resting eggs of the copepod. Infection of oysters by M. refringens was limited to June, July and August, coinciding with (1) the highest temperature recorded in the claire, and (2) the highest abundance of P. grani. PCR detection of M. refringens in P. grani during the summer period was linked to the release of parasite sporangia by the oyster. Our results are supported by previous results on the effective transmission of this parasite from the oyster to the copepod.     

Meta-analysis of Urine Heme Dipstick Diagnosis of Schistosoma haematobium Infection,Including Low-Prevalence and Previously-Treated Populations

Background

Urogenital schistosomiasis remains highly endemic in Africa. Current control is based on drug administration, targeted either to school-age children or to high-risk communities at-large. Urine dipsticks for detection of microhematuria offer an inexpensive means for estimating infection prevalence. However, their diagnostic performance has not been systematically evaluated after community treatment, or in areas with continuing low prevalence. The objective of the present study was to perform meta-analysis of dipstick accuracy for S. haematobium infection in endemic regions, with special attention to performance where infection intensity or prevalence was low.

Methodology/Principal Findings

This review was registered at inception with PROSPERO (CRD42012002165). Included studies were identified by computerized search of online databases and hand search of bibliographies and existing study archives. Eligible studies included published or unpublished population surveys irrespective of date, location, or language that compared dipstick diagnosis of S. haematobium infection to standard egg-count parasitology. For 95 included surveys, variation in dipstick sensitivity and specificity were evaluated according to study size, age- and sex-specific participation, region, local prevalence, treatment status, and other factors potentially affecting test performance. Independent of prevalence, accuracy was greater in surveys of school-age children (vs. adults), whereas performance was less good in North Africa, as compared to other regions. By hierarchical ROC analysis, overall dipstick sensitivity and specificity for detection of egg-positive urine were estimated at 81% and 89%, respectively. Sensitivity was lower among treated populations (72%) and in population subgroups having lower intensity infection (65%). When the insensitivity of egg count testing was considered (and diagnosis inferred instead from combined hematuria and egg-count findings), overall dipstick sensitivity/specificity were 82%/97%, with significantly better sensitivity (92%) in high prevalence settings.

Conclusions/Significance

This analysis suggests that dipsticks will continue to serve as very useful adjuncts for monitoring community prevalence following implementation of population-based control of urogenital schistosomiasis.     

Prevalence of scrapie infection in Great Britain: interpreting the results of the 1997-1998 abattoir survey

An accurate estimate of the prevalence of scrapie infection in the Great Britain (GB) sheep flock is essential when assessing any potential risk to human health through exposure to sheep transmissible spongiform encephalopathies (TSEs). One method for assessing the prevalence is to sample sheep intended for human consumption using a diagnostic test capable of detecting infected animals prior to the onset of clinical signs. An abattoir survey conducted in Great Britain in 1997-1998 tested brain samples from 2809 apparently healthy sheep of which none was found to be positive for scrapie by histopathology or immunohistochemistry (IHC) although 10 were positive for scrapie-associated fibrils (SAF). Subsequently, the tonsils from a subset of the animals sampled were examined using IHC, one of which tested positive. To interpret these results we use a likelihood-based approach, which accounts for the variation in the prevalence of infection with age and test sensitivity and specificity with stage of infection. Combining the results for all of the diagnostic tests yields an estimate of the prevalence of scrapie infection in the GB sheep flock of 0.22% (95% confidence interval: 0.01-0.97%). Moreover, our analysis suggests that all of the diagnostic tests used are very specific (greater than 99%). Indeed, only SAF detection yields a specificity estimate of less than 100%, which helps to account for the high number of samples found to be positive for SAF.     

Sample size calculations for surveys to substantiate freedom of populations from infectious agents

We develop a Bayesian approach to sample size computations for surveys designed to provide evidence of freedom from a disease or from an infectious agent. A population is considered "disease-free" when the prevalence or probability of disease is less than some threshold value. Prior distributions are specified for diagnostic test sensitivity and specificity and we test the null hypothesis that the prevalence is below the threshold. Sample size computations are developed using hypergeometric sampling for finite populations and binomial sampling for infinite populations. A normal approximation is also developed. Our procedures are compared with the frequentist methods of Cameron and Baldock (1998a, Preventive Veterinary Medicine34, 1-17.) using an example of foot-and-mouth disease. User-friendly programs for sample size calculation and analysis of survey data are available at http://www.epi.ucdavis.edu/diagnostictests/.     

Polymerase chain reaction for detection of endocervical Chlamydia trachomatis infection in women attending a gynecology outpatient department in India

OBJECTIVES: To detect Chlamydia trachomatis infection by polymerase chain reaction (PCR) in symptomatic women attending a gynecology clinic in a city hospital and in randomly selected slum dwellers. STUDY DESIGN: Endocervical specimens were collected from 350 women with genitourinary complaints (group I) and 53 slum dwellers (group II). Samples were analyzed by PCR, direct fluorescence assay (DFA) and Giemsa stain cytology for detection of C trachomatis and compared for their sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). RESULTS: The prevalence of endocervical C trachomatis infection was 43.1% and 24.5% in groups I and II, respectively. The sensitivity, specificity, PPV and NPV of PCR were 80.0%, 75.0%, 66.6% and 85.7%, respectively, when DFA was considered true positive. The percent increment in detection of C trachomatis by PCR was 15.3%. CONCLUSION: Giemsa stain cytology has low sensitivity and specificity; hence, it cannot be recommended for use as a diagnostic technique. It appears that PCR can be used routinely in Chlamydia diagnosis and in screening selected populations. The high positivity of C trachomatis infection in urban slum dwellers is cause for concern.     

Assessment of the diagnostic accuracy and relevance of a novel ELISA system developed for seroepidemiologic surveys of Helicobacter pylori infection in African settings

Beside diagnostic uncertainties due to the lack of a perfect gold standard test for Helicobacter pylori infection, the diagnosis and the prevalence estimation for this infection encounter particular challenges in Africa including limited diagnostic tools and specific genetic background. We developed and evaluated the accuracy of an enzyme-linked immunosorbent assay (ELISA) system tailored for H. pylori genetics in Africa (HpAfr-ELISA). Strains belonging to main genetic populations infecting Africans were exploited as sources for whole-cell antigens to establish in-house the ELISA system. A phase II unmatched case-control study explored the diagnostic accuracy of the HpAfr-ELISA using a training set of samples collected from dyspeptic patients from Kinshasa, the Democratic Republic of Congo (DRC) who had been tested with invasive standard tests (i.e., histology, culture, and rapid urease test) in 2017. Then the assay was cross-validated through a community-based survey assessing the prevalence of H. pylori and associated factors in 425 adults from Mbujimayi, DRC in 2018. Bayesian inferences were used to deal with statistical uncertainties of estimates (true prevalence, sensitivity, and specificity) in the study population. At its optimal cut-off-value 20.2 U/mL, the assay achieved an estimated sensitivity of 97.6% (95% credible interval [95%CrI]: 89.2; 99.9%) and specificity of 90.5% (95%CrI: 78.6; 98.5). Consistent outcomes obtained at repeated tests attested the robustness of the assay (negative and positive agreements always > 70%). The true prevalence of H. pylori was estimated 53.8% [95%CrI: 42.8; 62.7%]. Increasing age (adjusted odds ratio [aOR] > 1.0 [95% confidence interval (CI): > 1.0; 1.1]; p<0.001), overcrowding households (aOR = 3.2 [95%CI: 2.0; 5.1]; p<0.001), and non-optimal hand hygiene (aOR = 4.5 [95%CI: 2.0; 11.4]; p = 0.001) were independently associated with the H. pylori-seropositivity. The novel ELISA system has demonstrated good diagnostic accuracy and potential usefulness for management and mitigation strategies for H. pylori infection in African settings.     

Detection and characterisation of parasites causing emerging zoonoses

Understanding the epidemiology of zoonotic parasitic infections is dependent upon the availability of accurate and sensitive diagnostic techniques. The development of molecular diagnostic methods, particularly those utilising PCR for the detection of zoonoses will contribute greatly to the identification and control of these pathogens, by increasing the speed of diagnosis, specificity and sensitivity, reproducibility and ease of interpretation. Molecular characterisation studies allow us to distinguish between closely related infectious agents and to document the patterns of transmission of 'strains' and species within populations. This will allow precise determinations to be made about the aetiological agent, its characteristics and the source of infection. This review focuses on recent detection and characterisation techniques for both emerging and re-emerging parasite zoonoses.