TAXONOMY. Toxoplasma gondii. Toxoplasma gondii

Transcription

1 TAXONOMY (Levine 1982) Toxoplasma gondii seroprevalence in the Portuguese population: comparison of three cross-sectional studies spanning three decades Maria João Gargate National Reference Laboratory of Parasitic and Fungal Infections National Institute of Health Doutor Ricardo Jorge, I. P. Lisbon, Portugal Super-Kingdom: Eucaryota Kingdom: Animalia Sub-Kingdom: Protozoa (Goldfuss, 1918) Phylum: Apicomplexa (Levine, 1970) Class: Sporozoea (LeucKart, 1879) Sub-class : Coccidia (LeucKart, 1879) Order: Eucoccidiorida (Léger e Duboscq, 1910) Sub-order : Eimeriorina (Léger, 1911) Family: Sarcocystidae (Poche, 1913) Sub-family: Toxoplasmatinae (Biocca, 1957) Genus: Toxoplasma (Nicolle e Manceaux, 1909) Specie: Toxoplasma gondii (Nicolle e Manceaux, 1909) Toxoplasma gondii Toxoplasma gondii Nicolle e Manceaux, 1909 showed for the first time the presence of the parasite in the rodent Ctenodactylus gondii Oblígate intracellular protozoan Opportunistic parasite T. gondii is ubiquitous in nature and has a wide spectrum of prevalence across the globe Infects up to one-third of the world s population 1

2 Cysts: Skeletal muscle Heart Brain Eyes LIFE CYCLE Cerebral Cysts Toxoplasma gondii Oocysts Feline: Definitive host Cysts Human: Intermediate host Taquizoítos : Muscle and brain Sexual reproducion in the intestine of the feline Tachyzoites CONGENITAL TRANSPLANTATION TRANSFUSIONS TRANSMISSION FOOD Cysts Oocysts Humans acquire T. gondii through ingestion of tissue cysts in the undercooked meat of intermediate hosts, mainly pork and lamb by the ingestion of water or food contaminated by faeces containing oocysts from the definitive host or direct contact with cats rarely through transplantation of an infected organ or blood transfusion Mother to child transmission TRANSMISSION 2

3 CLINICAL SIGNS Toxoplasmosis is often benign in immunocompetent individuals (revealing no symptoms or may experience swollen lymph nodes), it induces major complications in immunocompromised individuals and during pregnancy, constituting a life-threatening disease Congenital toxoplasmosis can result in abortion or lead to severe malformation of the fetus or to visual or neurological injuries in the newborn, such as hydrocephalus, cerebral calcification and/or chorioretinitis. Guideline congenital Toxoplasmosis In Portugal the last (2011) guideline of the General Directorate of Health for toxoplasmosis screening, establish the surveillance of low-risk pregnancy based on three monthly retesting of susceptible women Of note, congenital toxoplasmosis is a mandatory notifiable disease in Portugal toxoplasmosis has recently been associated with neurological disorders, particularly schizophrenia and bipolar disorder. NÚMERO: 037/2011 DATA: 30/09/2011 ASSUNTO: Exames laboratoriais na Gravidez de Baixo Risco PALAVRAS CHAVE: Análises; Exames laboratoriais; Gravidez; Vigilância pré natal PARA: Médicos do Sistema Nacional de Saúde CONTACTOS: Divisão de Saúde Reprodutiva (secretariado.dsr@dgs.pt) Departamento da Qualidade na Saúde (dqs@dgs.pt) Nos termos da alínea c) do n.º 2 do artigo 2.º do Decreto Regulamentar n.º 66/2007, de 29 de maio, na redação dada pelo Decreto Regulamentar n.º 21/2008, de 2 de dezembro, a Direção Geral da Saúde, por proposta da Divisão de Saúde Reprodutiva e do Departamento da Qualidade na Saúde, emite a seguinte I NORMA 1. Na vigilância da gravidez de baixo risco devem ser realizados, ou estar documentados, os seguintes exames laboratoriais:.. g) Rastreio da Toxoplasmose.. Portuguese health national authorities consider that there was a lack of knowledge of the current epidemiological situation of toxoplasmosis in Portugal being the last data from the First National Serological Survey performed in 1979/1980 AIM OF THE STUDY To describe the seroprevalence trends in the Portuguese population (with special focus on women of childbearing age) over the past three decades ( , and 2013), by age group, region and gender. 3

4 Toxoplasma gondii seroprevalance 30 years ago METHODS Study design and sampling We performed three crosssectional seroprevalence studies (1979/1980, 2001/2002 and Portuguese National Serological Surveys ) based on an opportunistic sampling. Samples enrolled individuals of both genders, which were homogeneously distributed by age groups: 8 months 5 years, 6 15, 16 30, and 46 years. Each age group included individuals from each of the18 districts of Portugal that were representative of the population of each district. Portugal: 47% (1979) França: 54% EUA: 23% For the participation of individuals, a document was prepared with the objectives and benefits of the study and informed consent was obtained either from the participants themselves or from their legal representatives METHODS Serological analyses T. gondii IgG-specific antibodies were detected by using the automated methodology enzyme linked fluorescent assay sensibility 99.65% (interval confidence (CI) 94.55% to 97.39%), specificity 99.92% (CI 99.58% to 100%) and cut-off 4 titre<8 IU/mL, with the VIDAS TOXO IgGII commercial reagents (biomérieux SA, Marcy-l Étoile, France) according to the manufacturer s instructions. For the resolution of equivocal samples (ie, 4 titre<8 IU/mL), we retested them using a manual methodology of the direct agglutination test sensibility 96.22% (CI 94.55% to 97.39%), specificity 98.80% (CI96.46% to 99.60%) and cut-off 4 IU/mL, by using thetoxo Screen DA commercial reagents (biomérieuxsa, Marcy-l Étoile, France), according to the manufacturer s instructions. METHODS Statistical analysis Statistical analysis consisted of the estimation of the seroprevalences among the categories of the variables sex, age groups and region. Differences between the estimated seroprevalences were analysed using the χ2 test, considering the significance level of 5%. The stats package of R software (V.3.0.3) was used (R Development Core Team. R: A language and environment for statistical computing. Vienna, Austria: R Foundation for Statistical Computing, ISBN , URL. 4

5 N Seroprevalence(%) N Seroprevalence(%) N Seroprevalence(%) North % (46% to 56%) %(41% to 50%) % (10% to 17%) Centre % (43% to 51%) % (33% to 42%) % (25% to34%) Lisbon % (41% to 52% % (29%to37%) % (20% to27%) South % (38%to48%) % (19%to 32%) % (25% to 41%) A - Evolution of Toxoplasma gondii seroprevalence in Portugal over the past three decades / a significant decreasing trend during this 34-year period is illustrated B - Sample sizes for the three National Serological Surveys, the precise estimated seroprevalences and respective 95% confidence interval (CI). In the 2013 serological survey (n=1440), we observed an overall prevalence of T. gondii antibodies of 22% (95% CI 20% to 24%), whereas in the 2001/2002 survey (n=1657) the overall prevalence was 36% and in 1979/1980 was 47% Trends of Toxoplasma gondii seroprevalence in Portugal by region calculated with an interval confidence of 95% Trends of Toxoplasma gondii seroprevalence in Portugal by region calculated with an interval confidence of 95% Since there were no statistically significant differences between the 18 districts (data not shown), we grouped them into four regions: north, centre, Lisbon area and south. In the 2013 survey, the seroprevalences ranged from 13% (CI 95% 10% to 17%) in the north of Portugal to 33% (CI 95% 29% to 37%) in the south A decreasing trend was observed for the prevalence of T. gondii antibodies over the studied years in the four regions, with the exception of the south region that showed an increase of 8% (95% CI 2% to19%) between 2001/2002 and 2013 (tables 1 and 2). In particular, the decrease observed for the north region between these two surveys was statistically significant Comparison of Toxoplasma gondii seroprevalence trends, according to the data from three National Serological Surveys, by age groups. 5

6 Regarding the association between seroprevalence and age, we observed that the prevalence of specific T. gondii IgG increased significantly with this variable for each age group (eg, for the 2013 survey, χ2 test for trend in proportions gives a p value <0.001) and it generally decreased over time The only exception occurred for the age group 46 that revealed an increase from the 1979/1980 to the 2001/2002 survey Concerning the seroprevalence distribution by gender: we observed no significant differences and both genders showed a significant decrease in prevalence trough time Among the female population, we considered childbearing women aged years, and observed a significant decreasing trend in the seroprevalence in this group over time: 53% (95% CI 48% to 59%) in , 35% (95% CI 32% to 38%) in 2001/ % (95% CI 14% to 22%) in 2013 We also subdivided this population into five groups: 15 20, 21 26, 27 32, and years and observed that, like in the general population, there was a significant increase of T. gondii seroprevalence with age (except for a unique age group within the survey), and a significant decreasing trend over time. CONCLUSIONS Age group " % (41% to 60%) 19% (14% to 25%) 4% (2% to 10%) " % (44% to 67%) 23% (18% to 30%) 10% (4% to 19%) " % (35% to 58%) 34% (28% to 41%) 17% (10% to 28%) " % (45% to 72%) 48% (40% to 56%) 32% (20% to 49%) " % (47% to 72%) 62% (53% to 69%) 50% (37% to 63%) The 2013 serological survey established an overall prevalence of T. gondii specific IgG of 22%. This value indicates a prevalence that is similar to what has been described for other Mediterranean countries, which could be associated with the similarity between these countries in terms of climate, cat contact and diet.the ingestion of raw, undercooked or cured meats is the primary risk factor in Europe for acquiring toxoplasmosis and these countries present the same nutritional behavior and eating habits, namely the traditional consumption of cured meats. Toxoplasma gondii seroprevalence in childbearing women by age group calculated with an interval confidence of 95% 6

7 CONCLUSIONS CONCLUSIONS Since the consumption of raw or undercooked meat is considered to be the major source of T. gondii infection, we believe that this decreasing trend may be associated with: the practice of freezing meat; wide access to fast foods and pre-prepared meals, including frozen meat meals the introduction of intensive farming techniques involving the separation of cats from livestock, coupled with the reduction of breeding cattle in backyards; the release of legislation for toxoplasmosis, concerning sanitary inspection in the slaughterhouses the improvements in health education and information by health professionals, as the lack of awareness of disease sources of transmission is a crucial factor in the risk of infection In most human populations, the T. gondii seroprevalence increases with age, indicating that infection is acquired throughout life. Our study was no exception and showed a higher seroprevalence in older age groups (for all geographical regions), most likely due to their longer exposure to the risk factors. We observed that the prevalence of T. gondii IgG decreased over time, both in the general population and in the childbearing women (18% prevalence in 2013). More than 80% of childbearing women are susceptible to primary infection yielding a risk of congenital toxoplasmosis and respective sequelae. Since there is no vaccine to prevent human toxoplasmosis, the improvement of primary prevention constitutes a major tool to avoid infection in such susceptible group. The results of the present study fill an important gap in the Toxoplasma gondii seroprevalence in the Portuguese population as no data were available for the past 30 years. Toxoplasma gondii seroprevalence in the Portuguese population: comparisoof three cross-sectional studies spanning three decades. Gargaté MJ, Ferreira I, Vilares A, Martins S, Cardoso C, Silva S, Nunes B, Gomes JP. BMJ Open Oct 5;6(10):e doi: /bmjopen PMID: Thank you very much for your attention! 7

8 AGENTE INFECCIOSO 8