Modelling spatiotemporal distributions of Vulcanodinium rugosum and pinnatoxin G in French Mediterranean lagoons: Application to human health risk characterisation

Consumption of seafood contaminated by phycotoxins produced by harmful algae is a major issue in human public health. Harmful algal blooms are driven by a multitude of environmental variables; therefore predicting human dietary exposure to phycotoxins based on these variables is a promising approach in health risk management. In this study, we attempted to predict the human health risks associated with Vulcanodinium rugosum and its neurotoxins, pinnatoxins (PnTXs), which have been regularly found in Mediterranean lagoons since their identification in 2011. Based on environmental variables collected over 1 year in four Mediterranean lagoons, we developed linear mixed models to predict the presence of V. rugosum and PnTX G contamination of mussels. We found that the occurrence of V. rugosum was significantly associated with seawater temperature. PnTX G contamination of mussels was highest in summer but persisted throughout the year. This contamination was significantly associated with seawater temperature and the presence of V. rugosum with a time lag, but not with dissolved PnTX G in seawater. By using the contamination model predictions and their potential variability/uncertainty, we calculated the human acute dietary exposures throughout the year and predicted that 25% of people who consume mussels could exceed the provisional acute benchmark value during the warmest periods. We suggest specific recommendations to monitor V. rugosum and PnTX G.

[Brucellosis in Alpine ibex: 10 years of research and expert assessments]

Brucellosis due to Brucella melitensis affects domestic and wild ruminants, as well as other mammals, including humans. Despite France being officially free of bovine brucellosis since 2005, two human cases of Brucella melitensis infection in the French Alps in 2012 led to the discovery of one infected cattle herd and of one infected population of wild Alpine ibex (Capra ibex). In this review, we present the results of 10 years of research on the epidemiology of brucellosis in this population of Alpine ibex. We also discuss the insights brought by research and expert assessments on the efficacy of disease management strategies used to mitigate brucellosis in the French Alps.

Targeted strategies for the management of wildlife diseases: the case of brucellosis in Alpine ibex

The management of infectious diseases in wildlife reservoirs is challenging and faces several limitations. However, detailed knowledge of host-pathogen systems often reveal heterogeneity among the hosts' contribution to transmission. Management strategies targeting specific classes of individuals and/or areas, having a particular role in transmission, could be more effective and more acceptable than population-wide interventions. In the wild population of Alpine ibex (Capra ibex-a protected species) of the Bargy massif (French Alps), females transmit brucellosis (Brucella melitensis) infection in ~90% of cases, and most transmissions occur in the central spatial units ("core area"). Therefore, we expanded an individual-based model, developed in a previous study, to test whether strategies targeting females or the core area, or both, would be more effective. We simulated the relative efficacy of realistic strategies for the studied population, combining test-and-remove (euthanasia of captured animals with seropositive test results) and partial culling of unmarked animals. Targeting females or the core area was more effective than untargeted management options, and strategies targeting both were even more effective. Interestingly, the number of ibex euthanized and culled in targeted strategies were lower than in untargeted ones, thus decreasing the conservation costs while increasing the sanitary benefits. Although there was no silver bullet for the management of brucellosis in the studied population, targeted strategies offered a wide range of promising refinements to classical sanitary measures. We therefore encourage to look for heterogeneity in other wildlife diseases and to evaluate potential strategies for improving management in terms of efficacy but also acceptability.

Modeling the Inactivation of Viruses from the Coronaviridae Family in Response to Temperature and Relative Humidity in Suspensions or on Surfaces

Temperature and relative humidity are major factors determining virus inactivation in the environment. This article reviews inactivation data regarding coronaviruses on surfaces and in liquids from published studies and develops secondary models to predict coronaviruses inactivation as a function of temperature and relative humidity. A total of 102 D values (i.e., the time to obtain a log₁₀ reduction of virus infectivity), including values for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), were collected from 26 published studies. The values obtained from the different coronaviruses and studies were found to be generally consistent. Five different models were fitted to the global data set of D values. The most appropriate model considered temperature and relative humidity. A spreadsheet predicting the inactivation of coronaviruses and the associated uncertainty is presented and can be used to predict virus inactivation for untested temperatures, time points, or any coronavirus strains belonging to Alphacoronavirus and Betacoronavirus genera.IMPORTANCE The prediction of the persistence of SARS-CoV-2 on fomites is essential in investigating the importance of contact transmission. This study collects available information on inactivation kinetics of coronaviruses in both solid and liquid fomites and creates a mathematical model for the impact of temperature and relative humidity on virus persistence. The predictions of the model can support more robust decision-making and could be useful in various public health contexts. A calculator for the natural clearance of SARS-CoV-2 depending on temperature and relative humidity could be a valuable operational tool for public authorities.

Modeling the Inactivation of Viruses from the Coronaviridae Family in Response to Temperature and Relative Humidity in Suspensions or on Surfaces

Temperature and relative humidity are major factors determining virus inactivation in the environment. This article reviews inactivation data regarding coronaviruses on surfaces and in liquids from published studies and develops secondary models to predict coronaviruses inactivation as a function of temperature and relative humidity. A total of 102 D values (i.e., the time to obtain a log10 reduction of virus infectivity), including values for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), were collected from 26 published studies. The values obtained from the different coronaviruses and studies were found to be generally consistent. Five different models were fitted to the global data set of D values. The most appropriate model considered temperature and relative humidity. A spreadsheet predicting the inactivation of coronaviruses and the associated uncertainty is presented and can be used to predict virus inactivation for untested temperatures, time points, or any coronavirus strains belonging to Alphacoronavirus and Betacoronavirus genera.IMPORTANCE The prediction of the persistence of SARS-CoV-2 on fomites is essential in investigating the importance of contact transmission. This study collects available information on inactivation kinetics of coronaviruses in both solid and liquid fomites and creates a mathematical model for the impact of temperature and relative humidity on virus persistence. The predictions of the model can support more robust decision-making and could be useful in various public health contexts. A calculator for the natural clearance of SARS-CoV-2 depending on temperature and relative humidity could be a valuable operational tool for public authorities.

Toxoplasma gondii in beef consumed in France: regional variation in seroprevalence and parasite isolation

In France, the consumption of cattle and sheep meat appears to be a risk factor for infection of pregnant women with Toxoplasma gondii. Several nation-wide surveys in France have investigated the prevalence of T. gondii in sheep and pig meat, but little is known at present about the prevalence of the parasite in beef. The main objective of the present cross-sectional survey was to estimate the seroprevalence of T. gondii infection in beef consumed in France. A secondary objective was to attempt to isolate T. gondii from cattle tissues and to study the geographical and age variations of this seroprevalence. The overall estimate of seroprevalence of T. gondii in bovine carcasses (n = 2912), for a threshold of 1:6 was 17.38%. A strong age effect was observed (p < 0.0001) with a seroprevalence of 5.34% for calves (<8 months) and 23.12% for adults (>8 months). Seroprevalence estimates given by area of birth and area of slaughtering for adults showed that the areas with the highest seroprevalence were not the same between these two variables. Only two strains, corresponding to genotype II, were isolated from heart samples, indicating that there is a limited risk of human infection with T. gondii, which needs to be correlated with the food habit of consuming raw or undercook (bleu or saignant) beef. However, new questions have emerged, especially concerning the isolation of parasites from beef and the precise role of bovines, generally described as poor hosts for T. gondii, in human infection.

Critical Orientation in the Jungle of Currently Available Methods and Types of Data for Source Attribution of Foodborne Diseases

With increased interest in source attribution of foodborne pathogens, there is a need to sort and assess the applicability of currently available methods. Herewith we reviewed the most frequently applied methods for source attribution of foodborne diseases, discussing their main strengths and weaknesses to be considered when choosing the most appropriate methods based on the type, quality, and quantity of data available, the research questions to be addressed, and the (epidemiological and microbiological) characteristics of the pathogens in question. A variety of source attribution approaches have been applied in recent years. These methods can be defined as top–down, bottom–up, or combined. Top–down approaches assign the human cases back to their sources of infection based on epidemiological (e.g., outbreak data analysis, case-control/cohort studies, etc.), microbiological (i.e., microbial subtyping), or combined (e.g., the so-called ‘source-assigned case-control study’ design) methods. Methods based on microbial subtyping are further differentiable according to the modeling framework adopted as frequency-matching (e.g., the Dutch and Danish models) or population genetics (e.g., Asymmetric Island Models and STRUCTURE) models, relying on the modeling of either phenotyping or genotyping data of pathogen strains from human cases and putative sources. Conversely, bottom–up approaches like comparative exposure assessment start from the level of contamination (prevalence and concentration) of a given pathogen in each source, and then go upwards in the transmission chain incorporating factors related to human exposure to these sources and dose-response relationships. Other approaches are intervention studies, including ‘natural experiments,’ and expert elicitations. A number of methodological challenges concerning all these approaches are discussed. In absence of an universally agreed upon ‘gold’ standard, i.e., a single method that satisfies all situations and needs for all pathogens, combining different approaches or applying them in a comparative fashion seems to be a promising way forward.

High Shedding Potential and Significant Individual Heterogeneity in Naturally-Infected Alpine ibex (Capra ibex) With Brucella melitensis

Wildlife reservoirs of infectious diseases raise major management issues. In Europe, brucellosis has been eradicated in domestic ruminants from most countries and wild ruminants have not been considered important reservoirs so far. However, a high prevalence of Brucella melitensis infection has been recently identified in a French population of Alpine ibex (Capra ibex), after the emergence of brucellosis was confirmed in a dairy cattle farm and two human cases. This situation raised the need to identify the factors driving the persistence of Brucella infection at high prevalence levels in this ibex population. In the present paper, we studied the shedding pattern of B. melitensis in ibex from Bargy Massif, French Alps. Bacteriological examinations (1-15 tissues/samples per individual) were performed on 88 seropositive, supposedly infected and euthanized individuals. Among them, 51 (58%) showed at least one positive culture, including 45 ibex with at least one Brucella isolation from a urogenital sample or a lymph node in the pelvic area (active infection in organs in the pelvic area). Among these 45 ibex, 26 (30% of the total number of necropsied animals) showed at least one positive culture for a urogenital organ and were considered as being at risk of shedding the bacteria at the time of capture. We observed significant heterogeneity between sex-and-age classes: seropositive females were most at risk to excrete Brucella before the age of 5 years, possibly corresponding to abortion during the first pregnancy following infection such as reported in the domestic ruminants. The high shedding potential observed in young females may have contributed to the self-sustained maintenance of infection in this population, whereas males are supposed to play a role of transmission between spatial units through venereal transmission during mating. This heterogeneity in the shedding potential of seropositive individuals should be considered in the future to better evaluate management scenarios in this system as well as in others.

Dose-Response Modelling of Paralytic Shellfish Poisoning (PSP) in Humans

Paralytic shellfish poisoning (PSP) is caused by a group of marine toxins with saxitoxin (STX) as the reference compound. Symptoms in humans after consumption of contaminated shellfish vary from slight neurological and gastrointestinal effects to fatal respiratory paralysis. A systematic review was conducted to identify reported cases of human poisoning associated with the ingestion of shellfish contaminated with paralytic shellfish toxins (PSTs). Raw data were collected from 143 exposed individuals (113 with symptoms, 30 without symptoms) from 13 studies. Exposure estimates were based on mouse bioassays except in one study. A significant relationship between exposure to PSTs and severity of symptoms was established by ordinal modelling. The critical minimal dose with a probability higher than 10% of showing symptoms is 0.37 µg STX eq./kg b.w. This means that 10% of the individuals exposed to this dose would have symptoms (without considering the severity of the symptoms). This dose is four-fold lower than the lowest-observed-adverse-effect-level (LOAEL) established by the European Food Safety Authority (EFSA, 2009) in the region of 1.5 μg STX eq./kg b.w. This work provides critical doses that could be used as point of departure to update the acute reference dose for STX. This is the first time a dose-symptoms model could be built for marine toxins using epidemiological data.

Frequent hepatitis E virus contamination in food containing raw pork liver, France

Food products containing raw pork liver are suspected to be vehicles for transmission of hepatitis E virus. Four categories of food products, comprising 394 samples, were analyzed to determine hepatitis E virus prevalence. Virus was detected in 3%–30% of the different categories. Phylogenetic analysis showed high identity with human and swine sequences.

Chlamydia psittaci in ducks: a hidden health risk for poultry workers

Chlamydia psittaci is a zoonotic pathogen associated primarily with avian chlamydiosis also referred as psittacosis. Human psittacosis can lead to severe cases of respiratory disease. The mule duck is one of the main bird hybrids associated with human cases of psittacosis in France. In order to better understand the epidemiology of avian chlamydiosis, monitoring studies were performed in both breeder flocks and mule duck flocks. Surveys conducted in one professional duck bredding organization revealed little shedding in breeder flocks, whereas heavy but asymptomatic C. psittaci shedding was observed in most of the mule duck flocks, mostly when birds were reared in open range conditions on farms. Human cases of psittacosis linked to duck breeder flocks and their progeny led to detection of heavy shedders in all the suspected flocks despite no birds showing clinical signs. Offspring of one of the infected female flocks was analyzed and also proved to be infected by C. psittaci. Field studies suggest that C. psittaci infections in duck farms involve horizontal and probably vertical transmission but that the environment also plays an important role in maintaining infection on farms. In the light of the widespread occurrence of C. psittaci on duck farms, it has become urgent to clearly identify sources of contamination in order to take appropriate field management measures to minimize worker exposure.

The Bayesian microbial subtyping attribution model: robustness to prior information and a proposition

Attributing foodborne illnesses to food sources is essential to conceive, prioritize, and assess the impact of public health policy measures. The Bayesian microbial subtyping attribution model by Hald et al. is one of the most advanced approaches to attribute sporadic cases; it namely allows taking into account the level of exposure to the sources and the differences between bacterial types and between sources. This step forward requires introducing type and source-dependent parameters, and generates overparameterization, which was addressed in Hald's paper by setting some parameters to constant values. We question the impact of the choices made for the parameterization (parameters set and values used) on model robustness and propose an alternative parameterization for the Hald model. We illustrate this analysis with the 2005 French data set of non-typhi Salmonella. Mullner's modified Hald model and a simple deterministic model were used to compare the results and assess the accuracy of the estimates. Setting the parameters for bacterial types specific to a unique source instead of the most frequent one and using data-based values instead of arbitrary values enhanced the convergence and adequacy of the estimates and led to attribution estimates consistent with the other models' results. The type and source parameters estimates were also coherent with Mullner's model estimates. The model appeared to be highly sensitive to parameterization. The proposed solution based on specific types and data-based values improved the robustness of estimates and enabled the use of this highly valuable tool successfully with the French data set.

A qualitative risk assessment methodology for scientific expert panels

Risk assessment can be either quantitative, i.e. providing a numeric estimate of the probability of risk and the magnitude of the consequences, or qualitative, using a descriptive approach. The French Agency for Food, Environmental and Occupational Health and Safety (ANSES), formerly the French Food Safety Agency (AFSSA), bases its assessments on the opinions of scientific panels, such as the ANSES Animal Health Scientific Panel (AH-SP). Owing to the lack of relevant data and the very short period of time usually allowed to assess animal health risks on particular topics, this panel has been using a qualitative risk method for evaluating animal health risks or crises for the past few years. Some experts have drawn attention to the limitations of this method, such as the need to extend the range of adjectives used for the lower probabilities and to develop a way to assess consequences. The aim of this paper is to describe the improved method now established by the AH-SP, taking into account the limitations of the first version. The authors describe a new set of levels for probabilities, as well as the items considered when addressing either animal or human health consequences.

New strategy for the survey of Toxoplasma gondii in meat for human consumption

Monitoring of Toxoplasma infection in animals destined for human consumption is a great challenge for human toxoplasmosis prevention. This study aimed to compare results obtained from a naturally infected population of sheep using different tests and targeting an original matrix: meat samples and muscle fluids collected at the slaughterhouse. A commercial ELISA test was performed on diaphragm fluids from 419 ovine carcasses collected at the slaughterhouse. A MAT (modified agglutination test) was performed on heart fluids obtained from the same animals. In addition, all hearts were bioassayed in mice. Serological test agreement, the relative sensitivity of ELISA MAT and mouse bioassay as well as a correlation between titres and parasite isolation probability were statistically evaluated. The overall agreement (kappa coefficient=0.64) of ELISA on diaphragm fluids and MAT on heart fluids is substantial and subsequently both tests can be used for epidemiological studies. Relative sensitivity was higher for MAT performed on cardiac fluids (90%) than ELISA on diaphragm fluid (61%). For both serological tests, relative sensitivity is lower in lambs younger than 12 months. Relative sensitivity of mouse inoculation was 42%. A significant correlation was obtained between increasing MAT titres and probability to isolate live parasite from the heart. When the fluid titre was higher than 1:16, parasites were isolated in 65% of cases. When it was lower, isolation failed in 95% of the cases. According to our results, cardiac fluids appear to be a relevant matrix for toxoplasmosis survey in meat.

Ostreid herpesvirus 1 detection and relationship with Crassostrea gigas spat mortality in France between 1998 and 2006

Since its molecular characterisation, Ostreid herpesvirus 1 (OsHV-1) has been regularly detected in Crassostrea gigas in France. Although its pathogenicity was demonstrated on larval stages, its involvement during mortality outbreaks at the juvenile stage was highly suspected but not evidenced. To investigate mortality outbreaks, the French National Network for Surveillance and Monitoring of Mollusc Health (REPAMO) carried out two surveys in juvenile C. gigas. The first survey lasted from 1998 to 2006 and was an epidemiological inquiry occurring when oyster farmers reported mortality outbreaks. The second survey, a longitudinal one, was set up in 1998 to complete the network observations on OsHV-1. Data analysis showed a specific pattern of mortality outbreaks associated with OsHV-1 detection. Ostreid herpesvirus 1 detection mainly appeared during the summer, suggesting the influence of the seawater temperature on its occurrence. It mostly presented a patchy distribution in the field in contrast to the nursery. Significant relationship between OsHV-1 detection and spat mortality was found, preferentially in sheltered and closed environments. The longitudinal survey confirmed most of the network observations. Although subsequent works particularly epidemiological surveys would be useful to confirm the causal link between the detection of OsHV-1 and the mortality outbreaks in juvenile C. gigas, the role of OsHV-1 in oyster mortality is progressing.

A risk-based sampling plan for monitoring of histamine in fish products

In 2008, the French Institute for Public Health Surveillance reported an increase in the number of histamine food poisoning outbreaks and cases in France. The aim of this study was to propose a new monitoring plan for characterizing consumers' exposure to histamine through fishery products. As fish products of concern are numerous, we proposed that the number of samples allocated for a fish category be chosen based on the risk associated with the category. Point risk estimates of histamine poisoning were assessed with the Risk Ranger tool. Fresh fish with high histidine content was found to contribute most to the number of cases. The (estimated) risks associated with the consumption of canned and deep-frozen fish appear marginal as compared with the risk associated with fresh fish with high histidine concentrations. Accordingly, we recommend excluding canned and deep-frozen fish from the monitoring plan, although these risk estimates can be biased. Within a category, samples were proportional to the relative food consumption of the different fishes. The spatial and seasonal consumption patterns were also taken into account for the design of the new monitoring plan. By testing appropriate numbers of samples from categories of fish products of concern, this plan will permit investigation of trends or comparison of product categories presenting risks of histamine poisoning.

Validation of in situ hybridisation and histology assays for the detection of the oyster parasite Marteilia refringens

An in situ hybridisation technique has been developed for the detection of infection in oysters with Marteilia refringens with particular emphasis on light infections or confirmation of suspected cases by means of histology. Although validation of new diagnostic methods is usually achieved by comparison with standard techniques, in our case the sensitivity and specificity of the standard (histology) had not previously been established. Another point to consider is that surveillance and monitoring frequently target populations displaying different levels of prevalence under different field conditions. The objective of our study was to evaluate the sensitivity and specificity values of in situ hybridisation and histology for the detection of M. refringens, based on 3 populations of flat oysters, free of the disease and with mild and high levels of prevalence. A blind assay of 200 individuals from each population was performed using both techniques. Results were analysed by means of the classical approach and latent models (maximum likehood and Bayesian approach). Assumptions and results were found to vary slightly with the different statistical approaches. The more realistic estimate by the Bayesian approach shows a link between the level of prevalence and the sensitivity of the techniques. Values of sensitivity and specificity for histology were 0.7 and 0.99 respectively, and 0.9 and 0.99 respectively in the case of in situ hybridisation. Some uncertainty remains regarding these values because the study does not take into account the severity of infection or the developmental stages of the parasite actually present in each individual. This work provides valuable information with regard to the choice and potential use of those 2 diagnostic methods currently recommended by international standards.

Impact of a multidisciplinary approach to the control of antibiotic prescription in a general hospital

We examined the impact of a rational antibiotic prescription programme based on a multidisciplinary consultative approach in a 600-bed hospital. The programme involved four measures: (1). drawing up of a local prescribing consensus with all prescribers; (2). a restricted prescriptions policy for the most expensive antibiotics; (3.assessment of the prescription of these antibiotics by regular audits; and (4). institutional training and information for prescribers. The impact of the programme was assessed by comparing actual prescriptions with the criteria of the local consensus, compliance with the restrictive prescription policy, changes in the average daily cost of antibiotic therapy per inpatient and changes in the local ecology of methicillin-resistant Staphylococcus aureus (MRSA), Enterobacteriaceae producing extended-spectrum beta-lactamases (EPESB) and ceftazidime-resistant Pseudomonas species (CRP). Using a participatory consensual approach, 182 reference recommendations were established (104 for adults, 78 for children), corresponding to 85% of the clinical settings encountered in the hospital. Six audits, conducted since June 1997, show that the rate of unjustified prescriptions first fell significantly (from 6 to 0%, P<0.001), then increased significantly (from 0 to 3%, P<0.05) before stabilizing at 3%. The cost of antimicrobials per inpatient day fell significantly (from US dollars 13.8 in 1997 to US dollars 11 in 2000, P<0.001). The prevalence of MRSA and CRP remained stable, while that of EPESB fell significantly (P<0.001). This multidisciplinary consultative approach thus reduced antibiotic costs, contributed to infection control, and improved the quality of antibiotic prescription.

Vibrio carchariae, a pathogen of the abalone Haliotis tuberculata

Since 1997, mass mortality of the abalone Haliotis tuberculata L. has occurred in the natural environment along the French coast. The outbreak of disease started on the south coast of Brittany near Concarneau in 1997, then spread to the north of Brittany (in 1998) and the west coast of Normandy (Golfe de St. Malo in 1999). Between 60 and 80% of the abalone died. In 1999, mortality also affected a land-based abalone farm in Normandy during the summer. At this farm, a Vibrio sp. was isolated in abundance from abalone that had just died. The disease was experimentally reproduced by inoculation or by introducing the pathogen into the surrounding water. This vibrio, identified by genotypic and phenotypic characters, is related to V carchariae. It is similar to the V carchariae, responsible for mortality in the Japanese abalone Sulculus diversicolor supratexta, but some phenotypic characters differentiate both strains. In 2000, healthy abalone placed in 2 sites on the north and south coasts of Brittany died, and the pathogen V carchariae could be isolated from dead individuals, demonstrating that the pathogen was probably the cause of the abalone disease that has been occurring since 1997 in Brittany.

Detection of oyster herpesvirus DNA and proteins in asymptomatic Crassostrea gigas adults

Since 1972, several herpes-like virus infections have been reported among different bivalve species around the world. Most of these reports involved larvae or juveniles presenting high mortalities. Two case reports of herpes-like viruses concerned adult oysters, Crassostrea virginica in USA and Ostrea angasi in Australia. Molecular techniques including PCR and in situ hybridization (ISH) have been recently developed to detect the oyster herpesvirus genome. In the present study, 30 Pacific oyster, Crassostrea gigas, adults have been analyzed using three different techniques: PCR, ISH and immunochemistry, in order to detect herpesviruses in asymptomatic individuals. PCR and ISH allowed detection of oyster herpesvirus DNA in 93.3 and 86.6%, respectively, of analyzed oysters while polyclonal antibodies allowed detection of viral proteins in 76.6% of analyzed adult oysters. These results suggest that oyster herpesvirus infects adult oysters with high prevalence and that the virus may persist in its host after primary infection. The detection of viral DNA and viral proteins in the gonad of several individuals supports the hypothesis of a possible vertical transmission of the infection. Lastly, concordance among the three techniques used in this study is discussed.

[Analysis of mode of failure, their effects and criticality: improving of the hospital drug prescribing process]

Failure Mode, Effects, and Criticality Analysis (FMECA) is used in industry to prevent process or product failures. We studied the feasibility of this method in hospital organizations. FMECA was used to improve drug prescription in two medical wards. Failure modes were identified and classified hierarchically. Corrective actions were taken. Involvement of all the professionals concerned in this process was obtained, and has resulted in real acceptance of the proposed changes and in their effective realization.

Spermatid injection into human oocytes. II. Clinical application in the treatment of infertility due to non-obstructive azoospermia

We have reported recently the first birth after intrauterine transfer of embryos obtained by injection of round spermatids into oocytes in cases of unexpected azoospermia. Here we provide a complete documentation of the series of 11 cases in which this novel method of infertility treatment was employed. In four of these cases, elongated spermatids were identified in the ejaculate, and it was decided to perform elongated spermatid injection (ELSI). In the other six cases, only round spermatids were present, and round spermatid injection (ROSI) was done. In one case, ROSI was given preference to ELSI because of a very poor viability status of elongated spermatids present in the ejaculate. Fertilization of at least one oocyte was achieved in 10 of the 11 treatment cycles; the fertilization rate in these 10 cycles ranged between 7 and 100% with a mean value of 45%. All of the two-pronucleated zygotes cleaved and were transferred to the patient's uterus. A singleton pregnancy was achieved in two ROSI cycles. Both pregnancies developed uneventfully and resulted in the birth of normal infants. These data show the intra-ooplasmic injection of spermatids obtained from the ejaculate may become the treatment of first choice in patients with non-obstructive azoospermia.

Fertilization failure after subzonal sperm insertion associated with defective fusional capacity of acrosome-reacted spermatozoa

A case of an isolated impairment of the ability of acrosome-reacted spermatozoa to fuse with the oocyte is reported. This impairment was associated with fertilization failure after subzonal sperm insertion even though elevated numbers of spermatozoa were inserted per oocyte. This observation shows the need for further studies into the relationship between the acrosome reaction and the sperm-oocyte fusion to better understand the advantages and the limitations of subzonal sperm insertion in different types of sperm pathology.

Effect of pentoxifylline on sperm movement characteristics in normozoospermic and asthenozoospermic specimens

Preliminary evidence has suggested that the phosphodiesterase inhibitor pentoxifylline augments the fertilizing potential of asthenozoospermic sperm samples, presumably by improving sperm movement. Here, we used computer-assisted sperm movement analysis to compare the effects of pentoxifylline in normozoospermic and asthenozoospermic specimens. The study focused on the following issues: the changes in individual movement characteristics in response to pentoxifylline, the rapidity of the response, the effect of sperm capacitation on the response, the persistence of the response after drug removal and the variability of responses among asthenozoospermic individuals. Data obtained show that (i) pentoxifylline increases the curvilinear velocity, path velocity, straight-line velocity, lateral head displacement, beat cross frequency and sperm hyperactivation in both normozoospermic and asthenozoospermic specimens, (ii) pentoxifylline does not modify the percentage of motile spermatozoa, (iii) the pentoxifylline effect reaches a maximum within 10 min of treatment in fresh semen as well as in capacitated sperm suspensions and persists for at least 2 h after drug removal and (iv) pentoxifylline improves the movement characteristics in most asthenozoospermic individuals. Results are discussed with regard to methods of therapeutic application of pentoxifylline as an enhancer of sperm movement in assisted reproductive technology.

Role of the extra-follicular compartment in the ovulation of isolated rabbit ovarian follicles

Ovulation was never observed, even in the presence of gonadotrophins, when preovulatory follicles isolated from oestrous does were cultured in vitro (n = 112). If the follicles were co-cultured with pieces of ovarian tissue and gonadotrophins, then 50% ovulated (P less than 0.01). Attempts to replace the ovarian tissue by various steroid hormones or prostaglandins did not result in follicular rupture except when PGE-2 was used (23.8%, P less than 0.05). We suggest that gonadotrophins have an immediate (less than 1 h) action upon the follicle and ovarian interstitial tissue simultaneously. The response of the ovarian tissue to gonadotrophins is essential for eventual follicular rupture and involves PGE-2.

In-vitro ovulation of rabbit ovarian follicles isolated after the endogenous gonadotrophin surge

Follicular rupture was never observed when preovulatory rabbit follicles were isolated from the ovary before the ovulatory gonadotrophin discharge and placed in hormone-free culture for 10-14 h (n = 48). However, if the follicles were taken 1 h post coitum and cultured under the same conditions, 11/24 (45.8%) ruptured spontaneously. Follicular rupture under these conditions appeared to be chronologically and histologically comparable to that of ovulation in vivo. Culture in the presence of progesterone increased the proportion of follicles ovulating in vitro (17/23 = 73.9%; P less than 0.05). Inhibition in vitro of the synthesis of steroids or prostaglandins suppressed ovulation, although meiotic maturation of the oocyte did take place. These findings indicate that the follicle constitutes an independent entity within the ovary from 1 h post coitum.

[Revascularization of arteries of the leg by bypass in chronic arteriopathies of the lower limbs. Apropos of 50 cases]

The authors report 50 by-pass operations followed up for from 6 months to 4 years, which were designed to restore the blood supply via the leg arteries in peripheral arterial disease of the lower limbs. 40 patients were at stages III and IV; acute ischemia required emergency operation in 6 cases. 2 Patients died immediately after operation. 30 by-passes remained permeable. A cure of the trophic disorder and a functional improvement were obtained in 39 patients with only 8 subsequent amputations. In the light of the world literature and their personal experience they discuss the main pronostic factors and the indications for this method which has proved to be a remarkable progress in the treatment of severe arterial disease of the lower limbs.