Laboratory diagnosis of Toxoplasma gondii infection

Seroprevalence of Gestational and Neonatal Toxoplasmosis as well as Risk Factors in Yaoundé, Cameroon

Background. Toxoplasmosis, caused by Toxoplasma gondii in pregnant women, is a significant public health problem due to risk of mother to child transmission. The aim of the study was to determine the seroprevalence of toxoplasmosis in pregnant women and corresponding cord blood among women attending Biyem-Assi and CASS Nkoldongo hospitals in Yaoundé, Cameroon. Methods. An institutional based cross-sectional study was conducted between June 2019 and May 2020 on 300 pregnant women from late second trimester to third trimester. A total of 259 cord blood samples were collected at birth from these women. Toxoplasma gondii-specific IgG and IgM antibodies in maternal and cord blood were detected using the Toxoplasma Enzyme Immunosorbent Assay kit, and potential risk factors captured through questionnaire were identified using binary logistic regression model. Statistical significance was measured at $P<0.05$ . Results. The overall seroprevalence of gestational and neonatal toxoplasmosis was 80% and 88%, respectively. IgG seropositivity was 72.7%, IgM only was 1.3% and cooccurrence of IgG/IgM was 6% amongst pregnant women. Out of 259 newborn cord bloods, 72.2% were positive for IgG only, 8.9% for IgM only, and 23.9% for both IgG/IgM. Pregnant women 15-24 years ( $\text{AOR}=4.6$ , $P=0.011$ ) and women with primary level of education ( $\text{AOR}=3.9$ , $P=0.042$ ) were significantly at risk of infection with Toxoplasma gondii. Conclusion. Gestational and neonatal toxoplasmosis appears to be more common with higher risk of infection in younger women and less educated women. Hence, these findings will serve as baseline data for further investigations on mother to child transmission of toxoplasmosis in Yaoundé and the need for reinforcement of pregnant women toxoplasmosis-related health measures.

Epidemiology of Uveitis in a tertiary care centre in Portugal

Purpose: Evaluate the prevalence and incidence, demographic characteristics, anatomical classification, concomitant complications and treatment of uveitis, as well as its association with systemic diseases in the northern Portuguese population referred to a tertiary care centre (São João Hospital, Porto).Methods: A retrospective observational study of 545 consecutive uveitis cases was performed between 12th April 2012 and the 26th October 2017. Uveitis was classified according to Standard Uveitis Nomenclature, while aetiology and complications were diagnosed by specific clinical and laboratory testing.Results: Prevalence was calculated to be 12,4 cases per 100,000 people while incidence was 3.9 cases per 100,000 people annual incidence. The ratio of females to males was 1.32:1 and the mean age at diagnosis was 47,86 years. Anterior uveitis was the most common classification making up 47.5%, followed by non-infectious posterior uveitis 18,0%, infectious posterior uveitis 8,4%, intermediate uveitis 5,5% and panuveitis 4,2%. Extra-uveal entities made up the rest of the causes (16.4%). In terms of aetiology, the majority of uveitis was idiopathic (32,1%) followed by axial spondylarthritis (12.1%), Behçet's disease (8,8%), sarcoidosis (6,1%), tuberculosis (5,5%), herpes (5,1%), toxoplasmosis (3,1%) among other less frequent causes.Conclusion: In our referral region, 72% of uveitis cases were correctly identified surpassing other studies. There was a higher rate of intermediate uveitis and lower number of panuveitis cases when compared to a previous Portuguese study. Extensive monitoring of the development of uveitis by international multicentre prospective studies could be useful for increasing practitioner awareness and diagnostic approach.

A Review on the Present Advances on Studies of Toxoplasmosis in Eastern Africa

Toxoplasmosis is a zoonotic infection caused by the protozoan parasite, Toxoplasma gondii. It was discovered over 100 years ago and is credited as the most successful parasitic organism worldwide, able to infect and multiply in all warm blooded animals including an estimated 2.3 billion people. Toxoplasmosis is asymptomatic in immunocompetent individuals. Infection in the developing fetus and immunocompromised individuals can cause severe clinical disease. Toxoplasmosis is also a major cause of reproductive failure in livestock. The economic impact of toxoplasmosis is believed to be substantial. Factors associated with toxoplasmosis infection have been defined. Eastern Africa region is a high-risk area mainly due to the close association of humans and livestock as well as sociocultural practices, poor environmental hygiene, and poverty. The present paper provides a narrative review of published data on toxoplasmosis in Eastern Africa.

Help in the Choice of Automated or Semiautomated Immunoassays for Serological Diagnosis of Toxoplasmosis: Evaluation of Nine Immunoassays by the French National Reference Center for Toxoplasmosis

Toxoplasmosis, a benign infection, is asymptomatic or paucisymptomatic in over 80% of cases, except in immunocompetent patients suffering from ocular toxoplasmosis or in immunocompromised patients with opportunistic or congenital toxoplasmosis. Diagnosis is based mainly on serology testing. Thus, we compared the performance of the nine most commonly used commercial automated or semiautomated immunoassays for IgG and IgM Toxoplasma gondii antibody detection, that is, the Advia Centaur, Architect, AxSYM, Elecsys, Enzygnost, Liaison, Platelia, VIDAS, and VIDIA assays. The assays were conducted on four panels of serum samples derived during routine testing from patients with an interfering disease and who exhibited a low IgG antibody level in one of two clinical settings, namely, acute or chronic toxoplasmosis. As a result, IgG sensitivities ranged from 97.1% to 100%, and IgG specificities ranged from 99.5% to 100%. For IgG quantification, strong differences in IgG titers (expressed in IU/ml) were noted depending on the assay used. IgM sensitivities ranged from 65% to 97.9%, and IgM specificities ranged from 92.6% to 100%. For defining the best serological strategies to be implemented, it appears crucial to compare the diagnostic performance of the different tests with respect to their specificity and sensitivity in detecting the presence of IgG and IgM antibodies.

Seroepidemiology of Toxoplasma gondii infection in the Israeli population

Toxoplasmosis seroprevalence varies considerably between countries. We studied the seroprevalence of Toxoplasma gondii IgG antibodies in a national sample of the Israeli population; 2794 sera were tested. The highest age-adjusted seroprevalence rate was in Arabs (non-Bedouins) (60.4%), significantly higher compared to the rate in Jews (19.9%) and Bedouins (27.5%) (P < 0.01). There were no significant gender differences. Seropositivity increased with age in all population groups. For Jews, seropositivity was associated with place of birth and socioeconomic status. A finding of low seroprevalence rate in Bedouins despite their poor living conditions and close contact with livestock is surprising, and might be attributed to the dry and hot climate conditions in their area of residence. In women of reproductive age the seroprevalence was 15.1% in Jews, 25.4% in Bedouins and 72.3% in Arabs (non-Bedouins). Thus, the majority of pregnant women are susceptible to primary infection with T. gondii, and the risk for congenital toxoplasmosis remains high.

Neosporosis in a captive Parma wallaby (Macropus parma)

Infection with Neospora caninum has been diagnosed in a variety of animal species; however, reports in marsupials are rare. A captive Parma wallaby (Macropus parma) died suddenly and was subjected to necropsy examination. The main finding was necrotizing myocarditis associated with protozoan parasites. The protozoa were identified as N. caninum by use of immunohistochemistry and partial gene sequence analysis. Neospora and Toxoplasma should be considered a possible cause of disease in captive marsupials. Further work is required to determine whether marsupials are an accidental or terminal host of this protozoan in order to better understand the host-parasite relationship.