Prevalence, incidence and geographical distribution of Toxoplasma gondii antibodies in pregnant women in Denmark

Sero-prevalence and risk factors of Toxoplasma gondii infection in wild cervids in Denmark

Toxoplasma gondii is a zoonotic protozoan parasite capable of infecting possibly all warm-blooded animals including humans, and is one of the most widespread zoonotic pathogens known. Free-ranging wildlife can be valuable sentinels for oocyst contaminated environments, as well as a potential source for human foodborne infection with T. gondii. Here we aimed to determine the sero-prevalence of T. gondii in Danish wild deer populations and examine risk factors associated with increased exposure to the parasite. Blood samples were collected from 428 cervids (87 fallow deer (Dama dama), 272 red deer (Cervus elaphus), 55 roe deer (Capreolus capreolus) and 14 sika deer (Cervus Nippon) from 23 hunting sites in Denmark. The animals were shot during the hunting season 2017/2018, and screened for antibodies against T. gondii using a commercial ELISA kit. One hundred and five (24.5%) cervids were sero-positive. Sero-prevalence was significantly different between species (p < 0.05), with odds of sero-positivity being 4.5 times higher in roe deer than fallow deer, and 3.0 times higher in red deer than in fallow deer. A significant increase in sero-prevalence with age was observed, driven by a significant increase in risk in adult red deer compared to calves (OR: 13.22; 95% CI: 5.96–33.7). The only other significant risk factor associated with wild cervid T. gondii sero-positivity was fencing, with the highest exposure associated with deer from non-fenced hunting areas (OR: 2.21; 95% CI: 1.05–4.99). This study documented a widespread exposure to T. gondii in Danish cervids. Therefore the meat of the wild deer, in particular from roe deer and red deer, should be considered a significant risk of T. gondii infections to humans, if not properly cooked. Further, molecular studies to confirm the presence of infective parasitic stages in the muscles of deer used for consumption is recommended.

•

We document a widespread exposure to T. gondii in wild cervid species from Danish hunting estates.

•

The overall sero-prevalence of T. gondii in wild Danish cervids was 24.5% (N = 428).

•

Sero-prevalence was significantly different between the cervid species.

•

Risk factors associated with sero-positivity were age, species and fencing practices.

•

Undercooked deer meat should be considered a risk of T. gondii infections to humans.

The disease burden of ocular toxoplasmosis in Denmark in 2019: Estimates based on laboratory testing of ocular samples and on publicly available register data

Background

Toxoplasma gondii is an important zoonotic protozoan parasite with worldwide distribution. Information on the contribution of ocular toxoplasmosis to the disease burden caused by this parasite is limited or lacking from many countries.

Methods

We estimated the minimum occurrence of ocular toxoplasmosis in Denmark using results from direct detection of T. gondii DNA with qPCR and determination of the Goldmann-Witmer coefficient on ocular samples submitted by ophthalmological clinics and departments to the national reference laboratory in 2003–2019. In addition, we inferred incidence estimates using retrospective data that are publicly available in the National Patient Register, and we used unstructured expert elicitation as the basis for sensitivity analyses. We estimated the disease burden of ocular toxoplasmosis in 2019 in disability-adjusted life years (DALYs).

Findings

Ocular samples from 263 individuals (median age 57 years, range 2–88) had been tested with at least one of the methods during 2003–2019, and 42 (16%) tested positive (median age 65 years, range 14–85). In 2019, five (16%) of 31 tested individuals were positive, giving a minimum annual incidence estimate of 0.09 per 100.000 population. From this, we calculated a disease burden of at least 4 DALYs (95% confidence interval, 3–5). The age range suggested that this figure represented postnatally acquired ocular toxoplasmosis. The disease burden of ocular toxoplasmosis due to congenital toxoplasmosis has been previously estimated to be at least 12 DALYs, resulting in an estimated minimum total disease burden due to ocular toxoplasmosis of 16 DALYs. In 2005–2018, the mean annual number of diagnoses of ocular toxoplasmosis reported to the National Patient Register was 186, and the corresponding disease burden estimate was 134 DALYs (95% confidence interval, 113–158). Sensitivity analyses focusing on incidence and severity resulted in disease burden estimates in the range of 9–523 DALYs.

Interpretation

Because most diagnoses of ocular toxoplasmosis are based on clinical observations, ophthalmoscopy, and serology without confirmatory testing, the disease burden caused by ocular toxoplasmosis is likely substantially higher than our minimum estimates. Our results indicate that ocular toxoplasmosis contributes to the disease burden caused by T. gondii in Denmark, but uncertainty about the incidence and severity precludes reliable estimation of its importance.

Seroepidemiological study of toxoplasmosis in women referred to a pre-marriage counseling center in Alborz Province, Iran

Objectives

The aim of the current study was to assess prevalence of Toxoplasma infection and its associated risk factors in women of childbearing-age in central Iran.

Results

Of 400 serum samples assessed for anti-T. gondii antibodies, 81 (20.25%) samples were positive for anti-T. gondii antibodies, including 74 positive samples (91.3%) for anti-T. gondii IgG and seven positive samples (8.7%) for IgG and IgM. Of seven IgG and IgM positive samples, five and two samples were high and low in IgG avidity, respectively. Based on PCR analysis, Toxoplasma infection was detected in one sample with anti-T. gondii IgM and low IgG avidity. The Chi-square test showed significant correlations of T. gondii seropositivity with history of undercooked meat consumption and contacts with cats (p < 0.05). In the present study, 79.75% of the participants were negative for IgG against T. gondii infection. Furthermore, recently acquired Toxoplasma infection was found using IgG avidity and PCR assays among women of childbearing-age in the study area, which would increase the risk of their fetus becoming infected. Educational program and antenatal screening of childbearing-age women for T. gondii infection may be important primary prevention strategies and help reduce the risk of congenital toxoplasmosis in this population.

Seroprevalence of Toxoplasma gondii in domestic pigs, sheep, cattle, wild boars, and moose in the Nordic-Baltic region: A systematic review and meta-analysis

Background

Toxoplasma gondii is an important foodborne zoonotic parasite. Meat of infected animals is presumed to constitute a major source of human infection and may be a driver of geographical variation in the prevalence of anti-T. gondii antibodies in humans, which is substantial in the Nordic-Baltic region in northern Europe. However, data on seroprevalence of T. gondii in different animal species used for human consumption are scattered.

Methods

We conducted a systematic review of seroprevalence studies and meta-analysis to estimate the seroprevalence of T. gondii in five animal species that are raised or hunted for human consumption in the Nordic-Baltic region: domestic pigs (Sus scrofa domesticus), sheep (Ovis aries), cattle (Bos taurus), wild boars (Sus scrofa), and moose (Alces alces). We searched for studies that were conducted between January 1990 and June 2018, and reported in articles, theses, conference abstracts and proceedings, and manuscripts. Subgroup analyses were performed to identify variables influencing the seroprevalence.

Findings

From a total of 271 studies identified in the systematic review, 32 were included in the meta-analysis. These comprised of 13 studies on domestic pigs, six on sheep, three on cattle, six on wild boars, and four on moose. The estimated pooled seroprevalence of T. gondii was 6% in domestic pigs (CI_95%: 3–10%), 23% in sheep (CI_95%: 12–36%), 7% in cattle (CI_95%: 1–21%), 33% in wild boars (CI_95%: 26–41%), and 16% in moose (CI_95%: 10–23%). High heterogeneity was observed in the seroprevalence data within each species. In all host species except wild boars, the pooled seroprevalence estimates were significantly higher in animals >1 year of age than in younger animals. Not all studies provided information on animal age, sensitivity and specificity of the serological method employed, and the cut-off values used for defining an animal seropositive.

Conclusions

A substantial proportion of animals raised or hunted for human consumption in the region had tested positive for T. gondii. This indicates widespread exposure to T. gondii among animals raised or hunted for human consumption in the region. Large variations were observed in the seroprevalence estimates between the studies in the region; however, studies were too few to identify spatial patterns at country-level.

The disease burden of congenital toxoplasmosis in Denmark, 2014

BACKGROUND

Congenital toxoplasmosis (CT) causes a substantial disease burden worldwide. The aim of this study was to estimate the disease burden of CT in Denmark, a developed country with free public healthcare and nationwide data available.

METHODS

Using data primarily from two public health surveillance programmes conducted between 1992 and 2007, we estimated the incidence, occurrence of sequelae, mortality and the burden of disease in terms of disability-adjusted life years (DALYs) of CT in Denmark in 2014.

FINDINGS

We estimated that 14 children were born with CT in 2014, of which six will have developed sequelae by the age of 12. CT resulted in a total disease burden of 123 DALYs (95% uncertainty interval [UI], 100-148), of which 78 (95% UI, 64-94) were due to foetal loss and 2 (95% UI, 1-3) were due to neonatal death; the remaining burden was due to moderate to severe life-long sequelae. A comparison of the estimated incidence of CT with the number of reported CT cases in 2008-2014 indicated that for each reported CT case, at least five other CT cases could be expected to have occurred and gone unreported.

INTERPRETATION

Early onset, severity, and life-long duration of sequelae have a major effect on the disease burden of CT. Our data suggest that CT is under-diagnosed or under-reported in Denmark. The estimated disease burden and public health impact in Denmark is lower than in other European countries, highlighting the need for country-specific studies.

Toxoplasmosis awareness, seroprevalence and risk behavior among pregnant women in the Gampaha district, Sri Lanka

BACKGROUND

Primary gestational toxoplasmosis can be transmitted to the fetus with deleterious effects on the pregnancy. There is very little information regarding gestational toxoplasmosis in Sri Lanka. This survey was done to determine the prevalence and awareness of toxoplasmosis and to identify risk factors of infection among pregnant women in the Gampaha district, Sri Lanka.

METHODS

Women attending obstetric clinics at the Colombo North Teaching Hospital in 2014 were tested for Toxoplasma gondii (T. gondii) specific Immunoglobulins G (IgG) and M (IgM) subtypes using the OnSite Toxo IgG/IgM Rapid Test-Dip Strip(®). Disease awareness and risk behaviors of the participants were investigated.

RESULTS

Of the 293 participants (mean age 27 years, SD ± 5.92), 38% were primigravidae with a mean gestational age of 16.2 weeks (SD 7). The prevalence of anti-T. gondii IgG and IgM antibodies was 12.3% (n = 36) and zero, respectively. Unadjusted and adjusted odds ratios were calculated to determine risk factors of infection (cat-ownership, handling cats, consumption of meat, commercial meals and unwashed raw vegetables and fruits, handling soil and not washing hands after handling soil). On bivariate analysis, eating commercially prepared meals weekly or more was associated with toxoplasma seroprevalence with marginal statistical significance. On multivariate analysis, none of the considered risk factors were significant. Toxoplasma awareness was 4.4% (n = 13); health personnel (46.2%, n = 6) and media (53.8%, n = 7) being sources of information.

CONCLUSIONS

Health education programs to increase awareness of toxoplasmosis is recommended at antenatal clinics.

Toxoplasmosis not transmitted by cat bite, but high prevalence of antibodies to Toxoplasma gondii in patients bitten by their own cat

The aims of the study were to investigate the prevalence of antibodies to Toxoplasma gondii in a group of patients bitten by cats, and also to determine if toxoplasmosis can be transferred by cat bite. Seventy-two patients who attended the emergency wards at 3 hospitals in Stockholm, Sweden, due to infection by cat bite, were investigated for specific IgM and IgG antibodies to T. gondii in the acute phase, as well as in the convalescent phase about 2 weeks later. Specific IgG antibodies to T. gondii (> or =8 IU/ml) were found in 17/72 patients (24%) in the acute phase. No case of seroconversion occurred. Patients who were bitten by their own cat had positive antibody titres to T. gondii significantly more often than those bitten by a foreign cat; 30% and 5%, respectively (p = 0.02). This suggests that regular contact with cats may contribute to the transmission of the parasite.

Seroprevalence of human toxocariasis in Denmark

The seroprevalence of Toxocara in the Danish population was assessed from 3,247 sera from individuals originally screened for toxoplasmosis. Of 87 enzyme-linked immunosorbent assay-positive sera, 79 were confirmed by Western blotting, yielding a crude seroprevalence of 2.4%. This indicates that the seroprevalence of toxocariasis in Denmark is low compared to those in other European countries.

Toxoplasmosis snapshots: global status of Toxoplasma gondii seroprevalence and implications for pregnancy and congenital toxoplasmosis

Toxoplasma gondii's importance for humans refers mainly to primary infection during pregnancy, resulting in abortion/stillbirth or congenital toxoplasmosis. The authors sought to evaluate the current global status of T. gondii seroprevalence and its correlations with risk factors, environmental and socioeconomic parameters. Literature published during the last decade on toxoplasmosis seroprevalence, in women who were pregnant or of childbearing age, was retrieved. A total of 99 studies were eligible; a further 36 studies offered seroprevalence data from regions/countries for which no data on pregnancy/childbearing age were available. Foci of high prevalence exist in Latin America, parts of Eastern/Central Europe, the Middle East, parts of south-east Asia and Africa. Regional seroprevalence variations relate to individual subpopulations' religious and socioeconomic practices. A trend towards lower seroprevalence is observed in many European countries and the United States of America (USA). There is no obvious climate-related gradient, excluding North and Latin America. Immigration has affected local prevalence in certain countries. We further sought to recognise specific risk factors related to seropositivity; however, such risk factors are not reported systematically. Population awareness may affect recognition of said risks. Global toxoplasmosis seroprevalence is continuingly evolving, subject to regional socioeconomic parameters and population habits. Awareness of these seroprevalence trends, particularly in the case of women of childbearing age, may allow proper public health policies to be enforced, targeting in particular seronegative women of childbearing age in high seroprevalence areas.

Congenital toxoplasmosis: priorities for further health promotion action

Toxoplasmosis is a disease of considerable public health impact. As the transmission, occurrence and phenotype of this disease are influenced in a complex way by host genetics, immunity, behaviour and by the agent characteristics, prevention will not be simple. This article aimed to review studies defining seroprevalence of and characteristic sociodemographic, biological and lifestyle risk factors for Toxoplasma gondii infection in pregnant women, to evaluate screening and educational programmes, and to assemble recommendations for combating toxoplasmosis in populations at risk. Electronic databases were searched, using a specific search strategy, from 1975 to 2007. There is a high prevalence of T. gondii antibodies in pregnant women worldwide, with some geographic discrepancies attributed to climatic conditions, local food customs, hygiene, lifestyle and cultural differences. The main risk factors for toxoplasmosis in pregnant women are unsanitary feeding habits, poor immune system, contact with cats, contact with soil, pregnancy, number of births, older age, race, travelling outside the country, drinking beverages prepared with unboiled water, consumption of municipal or uncontrolled (well/spring) water and T. gondii strain virulence. Knowledge of these risk factors helps to identify priorities for further epidemiological work and defines effective preventive measures along five main themes of action: information and health education; screening of pregnant women and infants; limiting harm from risk behaviour; treatment of cases found to be at risk; and vaccination.

Disease burden of congenital toxoplasmosis

Although the outcomes of toxoplasmosis have been well documented, an integrated estimate of the impact of this infection on the health status of the population is not available. "Disability-adjusted life years" are the sum of years of life lost and years lived with disability, weighted for the severity of the illness. The estimated disease burden of congenital toxoplasmosis in The Netherlands is 620 (range, 220-1900) disability-adjusted life years per year, which is similar to that for salmonellosis and is mainly caused by fetal loss and chorioretinitis. However, there is considerable uncertainty in this estimate. Scenario analysis indicates that the true burden may be underestimated. In other countries, the disease burden is expected to vary with the incidence of congenital infection, but it may also depend on the health care system. In countries that actively screen for toxoplasmosis, such as France, there may be a lower burden of morbidity but a higher burden of mortality.

Influence of latent 'asymptomatic' toxoplasmosis on body weight of pregnant women

The latent toxoplasmosis is usually considered to be asymptomatic, however, this paradigm has never been rigorously tested. Here we searched for symptoms of deterioration of physical health (decrease of weight) in infected people by analysis of clinical records of 758 women tested for toxoplasmosis in the 16th week of gravidity. Toxoplasma-positive women have a lower body weight in the 16th week of gravidity (p = 0.02) than Toxoplasma-negative women. Moreover, a negative correlation between weight and the duration of toxoplasmosis was found in a subset of 174 Toxoplasma-positive women (p = 0.04), suggesting that slow and cumulative effects of latent toxoplasmosis, rather than a transient effect of acute toxoplasmosis, are responsible for the decreased weight of infected subjects. Longer duration of gravidity estimated from the date of last menstruation in the set of Toxoplasma-positive women in the 16th week of gravidity estimated with ultrasonography (p = 0.04) suggests a possibility of retarded foetal growth in Toxoplasma-positive women. The prevalence of latent toxoplasmosis is extremely high. Therefore, even its mild symptoms such as the decreased body weight in Toxoplasma-positive pregnant women might in fact indicate an unrecognized serious public health problem.

Toxoplasma gondii: from animals to humans

Toxoplasmosis is one of the more common parasitic zoonoses world-wide. Its causative agent, Toxoplasma gondii, is a facultatively heteroxenous, polyxenous protozoon that has developed several potential routes of transmission within and between different host species. If first contracted during pregnancy, T. gondii may be transmitted vertically by tachyzoites that are passed to the foetus via the placenta. Horizontal transmission of T. gondii may involve three life-cycle stages, i.e. ingesting infectious oocysts from the environment or ingesting tissue cysts or tachyzoites which are contained in meat or primary offal (viscera) of many different animals. Transmission may also occur via tachyzoites contained in blood products, tissue transplants, or unpasteurised milk. However, it is not known which of these routes is more important epidemiologically. In the past, the consumption of raw or undercooked meat, in particular of pigs and sheep, has been regarded as a major route of transmission to humans. However, recent studies showed that the prevalence of T. gondii in meat-producing animals decreased considerably over the past 20 years in areas with intensive farm management. For example, in several countries of the European Union prevalences of T. gondii in fattening pigs are now <1%. Considering these data it is unlikely that pork is still a major source of infection for humans in these countries. However, it is likely that the major routes of transmission are different in human populations with differences in culture and eating habits. In the Americas, recent outbreaks of acute toxoplasmosis in humans have been associated with oocyst contamination of the environment. Therefore, future epidemiological studies on T. gondii infections should consider the role of oocysts as potential sources of infection for humans, and methods to monitor these are currently being developed. This review presents recent epidemiological data on T. gondii, hypotheses on the major routes of transmission to humans in different populations, and preventive measures that may reduce the risk of contracting a primary infection during pregnancy.

Correlation of duration of latent Toxoplasma gondii infection with personality changes in women

Many parasites induce characteristic changes in behavior of their hosts. In humans latent toxoplasmosis is associated with changes in personality profiles. It has been already shown that a decrease in superego strength is correlated with duration of toxoplasmosis in men. Here we studied changes in personality profiles with Cattell's 16 PF questionnaire in Toxoplasma-infected women. The changes were measured as differences in personality factors between Toxoplasma-infected subjects and uninfected controls of the same age. The low-rate changes were studied in 230 women diagnosed with acute toxoplasmosis during past 14 years. The results showed the correlation between duration of toxoplasmosis and level of factors G (high superego strength) and Q3 (high strength of self sentiment). The high-rate changes were estimated by measuring the correlation between level of Toxoplasma-antibody titers (which rapidly decline after the end of acute phase of toxoplasmosis) and personality factors in an experimental set of 55 young mothers with latent toxoplasmosis. Again, certain factors, namely A (affectothymia), F (surgence), G (high superego strength), H (parmia), and L (protension), correlated with the length of the infection. We suggest that the parasite induced the changes in the personality profiles of the women because of our observation of an increasingly different personality profile over time between women with latent infection and controls. The same evidence questions the view that women with a particular personality profile are more prone to acquisition of T. gondii infection.

Control of congenital infection with Toxoplasma gondii by neonatal screening based on detection of specific immunoglobulin M antibodies eluted from phenylketonuria filter-paper blood-spot samples

Two ongoing neonatal screening programmes for congenital infection with Toxoplasma gondii are presented. The New England Newborn Screening Programme has included congenital toxoplasmosis since 1986. The test is based on detection of Toxoplasma-specific immunoglobulin M (IgM) antibodies eluted from the phenylketonuria (PKU) card. The seroprevalence of Toxoplasma IgG antibodies is at present about 13% and the birth prevalence of congenital toxoplasmosis approximately 1 per 10000 liveborn children. The Danish national neonatal screening programme was expanded to include congenital toxoplasmosis from 1 January 1999. The test is also based on detection of Toxoplasma-specific IgM antibodies eluted from PKU cards. The seroprevalence of Toxoplasma IgG antibodies in pregnant women is around 25% and the birth prevalence about 1 per 3000 liveborn children. The birth prevalence of congenital Toxoplasma infection is within the range of other congenital disorders included in different screening programmes. Neonatal screening is feasible in areas with a low risk of congenital infection where prenatal screening will not be applicable.

Incidence of Toxoplasma gondii infection in 35,940 pregnant women in Norway and pregnancy outcome for infected women

From 1992 to 1994 a screening program for detection of specific Toxoplasma gondii antibodies involving 35,940 pregnant women was conducted in Norway. For women with serological evidence of primary T. gondii infection, amniocentesis and antiparasitic treatment were offered. The amniotic fluid was examined for T. gondii by PCR and mouse inoculation to detect fetal infection. Infants of infected mothers had clinical and serological follow-up for at least 1 year to detect congenital infection. Of the women 10.9% were infected before the onset of pregnancy. Forty-seven women (0.17% among previously noninfected women) showed evidence of primary infection during pregnancy. The highest incidence was detected (i) among foreign women (0.60%), (ii) in the capital city of Oslo (0.46%), and (iii) in the first trimester (0.29%). Congenital infection was detected in 11 infants, giving a transmission rate of 23% overall, 13% in the first trimester, 29% in the second, and 50% in the third. During the 1-year follow-up period only one infant, born to an untreated mother, was found to be clinically affected (unilateral chorioretinitis and loss of vision). At the beginning of pregnancy 0.6% of the previously uninfected women were falsely identified as positive by the Platelia Toxo-IgM test, the percentage increasing to 1.3% at the end of pregnancy. Of the women infected prior to pregnancy 6.8% had persisting specific immunoglobulin M (IgM). A positive specific-IgM result had a low predictive value for identifying primary T. gondii infection.

Toxoplasmosis in Danish AIDS patients

Infection with Toxoplasma gondii was studied in 600 patients with AIDS, diagnosed in the eastern part of Denmark from 1980 up to and including 1990. The median age was 38 years, and 223 (44%) had anti-T. gondii IgG antibodies. Of the patients seropositive to T. gondii 61 (27%) developed toxoplasma encephalitis (TE). Few patients received prophylactic treatment with sulfamethoxazole-trimetoprim. In total, 66 patients were diagnosed with TE. One had no serological test performed, and of the remaining 65, 4 (6%) had no anti-T. gondii IgG antibodies. The predictive value of a negative Sabin-Feldman dye test was 99%. The geometric mean dye test titer was higher in patients with TE than in patients without TE. Of the patients with TE 34% had serological reactivation of their T. gondii infection at the time of TE diagnosis, and 34% had detectable T. gondii-specific antibodies in the cerebrospinal fluid. Specific IgM antibodies were found to have little value in the diagnosis of TE, as only 3% had detectable IgM antibodies. Acute toxoplasmosis was the AIDS-defining diagnosis for 23 (35%) of the patients with TE. The median CD4 count at the time of TE was 30 x 10(6)/l, and the median survival time from diagnosis of TE was 9 months.

Seroprevalence of toxoplasma antibodies among the antenatal population in Bangladesh

OBJECTIVE

To determine the seroprevalence of toxoplasma antibodies toxoplasma IgG and toxoplasma IgM) among an antenatal population in a hospital of Bangladesh.

METHODS

Sera from 286 pregnant women were tested for toxoplasma IgG antibody by applying enzyme linked immunosorbent assay (ELISA) technique. Among the 286 sera, 88 sera were randomly selected and tested for toxoplasma IgM applying ELISA.

RESULTS

Among 286 patients 110 (38.5%) were positive for toxoplasma IgG antibody and among 88 patients only one (1.1%) was positive for toxoplasma IgM. The seroprevalence gradually increased with age and parity. The seroprevalence of antibody was higher among the women in poor (53.0%) than the upper socio-economic class (22.0%) and among the women with jobs (55.0%) than the housewife group (35.0%).

CONCLUSION

This study shows that toxoplasmosis is endemic in Bangladesh and also affecting pregnant women. There is need for further detailed studies on toxoplasmosis and its influence on perinatal morbidity and mortality.

Influence of age on rates of new AIDS-defining diseases and survival in 6546 AIDS patients

It has consistently been reported that older AIDS patients have a shortened survival compared with younger patients. The aim of the present study was to investigate whether this difference in survival is caused by differences in the pattern of the complicating diseases. Information on patient follow-up after the AIDS diagnosis was obtained by retrospective case note review. The 6,546 patients were followed from the time of AIDS diagnosis as part of the multicentre AIDS in Europe study, which examined AIDS cases diagnosed at 52 centres in 17 European countries between 1979 and 1989. Occurrence of AIDS-defining events and demographic variables were recorded for all patients, and CD4 lymphocyte count at the time of AIDS diagnosis for approximately half the patients. After adjusting for imbalances in other variables, persons > or = 50 years of age had a significantly higher risk of contracting AIDS wasting syndrome, AIDS dementia complex and oesophageal candidiasis after the initial AIDS diagnosis, compared with age group 30-39 years [relative risk (RR) 95% confidence interval (CI)], 3.23 (2.70-3.75 CI); 2.48 (2.16-2.80 CI); 1.55 (1.26-1.83 CI), respectively]. Shortened survival after the time of AIDS diagnosis was associated with older age. After adjusting for pattern of complicating diseases, the age effect remained unchanged. Older age predisposes to AIDS-related wasting syndrome, AIDS dementia complex and oesophageal candidiasis. Independent of these differences, older age is significantly associated with shortened survival, suggesting that factors such as severity of complicating diseases or the capability of handling serious infections, rather than disease pattern, are responsible for the shortened survival.

Increased fetal nuchal translucency thickness at 10-14 weeks: is screening for maternal-fetal infection necessary?

OBJECTIVE

To investigate the relation between increased fetal nuchal translucency thickness at 10-14 weeks of gestation and maternal-fetal infection.

DESIGN

Prospective study.

SETTING

Harris Birthright Research Centre for Fetal Medicine.

POPULATION

Four hundred and twenty-six chromosomally normal pregnancies with increased fetal nuchal translucency thickness at 10-14 weeks of gestation and 63 with 'unexplained' second or third trimester fetal nuchal oedema or hydrops.

METHODS

Maternal serum infection screening and investigations for fetal infection in those with evidence of recent maternal infection.

MAIN OUTCOME MEASURES

Maternal and fetal infection.

RESULTS

Evidence of recent maternal infection was present in six of the 426 pregnancies (1.4%) with increased fetal nuchal translucency thickness at 10-14 weeks, but in all cases a healthy infant was born with no evidence of infection. In contrast, 'unexplained' second or third-trimester fetal hydrops was associated with maternal infection in six of the pregnancies (9.5%) and in all cases there was evidence of fetal infection.

CONCLUSIONS

Maternal-fetal infection is one of the causes of second or third trimester nuchal oedema or fetal hydrops. In contrast, the presence of increased nuchal translucency in the first trimester is not a marker of either maternal or fetal infection.

Classification system and case definitions of Toxoplasma gondii infection in immunocompetent pregnant women and their congenitally infected offspring. European Research Network on Congenital Toxoplasmosis

Classification systems and case definitions provide the foundations upon which clinical and epidemiological studies are based. The European Research Network on Congenital Toxoplasmosis acknowledged the lack of such a system or definitions within its field of interest and established a working group to address the issue. Congenital Toxoplasma gondii infection was defined as occurring in four separate patient groups: pregnant women, fetuses, infants, and individuals > 1 year of age. The likelihood of Toxoplasma gondii infection was separated into five mutually exclusive categories: definite, probable, possible, unlikely, and not infected. Inclusion within a specific category is dependent upon the case definition, which is in turn derived from criteria based on serological, parasitological, and clinical information. Notes are included within the classification not only to clarify the definitions, but also to improve the reliability and quality of diagnosis. The goal is to construct a system that encompasses all aspects of congenital toxoplasmosis, which is applicable to different countries and health services, suitable for large epidemiological studies, aids the diagnosis and management of individual cases, and lends itself to computerisation.

Detection by enzyme immunosorbent assay of Toxoplasma gondii IgG antibodies in dried blood spots on PKU-filter paper from newborns

Different ways of eluting IgG antibodies against Toxoplasma gondii from blood spots on PKU filter papers from newborns were examined, and the eluate was analysed by Enzyme Immunosorbent Assay (EIA). 10-mm diameter discs (method A), and 3-mm discs (method B) were eluted overnight, and 3-mm discs were eluted directly for 2 hours in the EIA wells (method C). Two groups of paired samples were tested: blood spots on the PKU card from the newborn, cord blood, and a venous blood sample from the mother collected shortly after delivery (Group 1, 191 samples); or PKU cards from the newborns and serum collected from the mother during the first trimester (Group 2, 426 samples). The best results were found for Group 1; method A, a sensitivity of 100% (63/63), and a specificity of 100% (128/128) (r = 0.934, P < 0.0001), and for Group 2; method C, a sensitivity of 100% (125/125), and a specificity of 100% (301/301) (r = 0.822, P < 0.0001). When method C, was used on 188 samples stored for 16-18 month at -20 degrees C, a sensitivity of 100% (62/62) and a specificity of 99.2% (125/126) (r = 0.913, P < 0.0001) were found. The PKU filter paper method is reliable and reproducible, and can be used in screening projects based on analysis of neonatal samples, and in epidemiological studies on toxoplasmosis in pregnant women.

Antimicrobial antibodies in Danish slaughterhouse workers and greenhouse workers

As a consequence of contact with animals and animal products slaughterhouse workers might be at risk of infection with pathogenic microorganisms. This hypothesis has been supported by some earlier studies. In this study 217 slaughtermen and a control group of 113 greenhouse workers were investigated for the prevalence of serum antibodies to Toxoplasma gondii, Campylobacter jejuni (IgA and IgG), Yersinia enterocolitica types 3 and 9, Yersinia pseudotuberculosis types I, II, III, IV, and V, Salmonella typhi, Salmonella paratyphi, Salmonella enteritidis, Salmonella typhimurium, and Borrelia burgdorferi. No significant differences were found concerning either frequency of positive tests or magnitude of titers. The prevalence of toxoplasma antibodies was remarkably high in both groups.