First isolation and molecular characterization of Toxoplasma gondii strains from human congenital toxoplasmosis cases in Monastir, Tunisia

Abstract

Toxoplasma gondii is a protozoon parasite that can cause severe clinical problems such as congenital toxoplasmosis. the distribution of T. gondii genotypes varies from one geographic area to another. So far, little is known about the parasite genotypes in tunisia, north Africa. the present study aimed isolating and genotyping T. gondii from the amniotic fluid (AF) and placenta of pregnant women in Monastir, Tunisia. Amniotic fluid and/or placenta from 80 women who acquired toxoplasma infection during pregnancy were tested by PCR and/or mouse bioassay. Genotyping of T. gondii isolates from these samples was performed with 15 microsatellite markers. Four viable T. gondii strains were isolated from either the AF or placenta of four women. Specifically, strains TUN001-MON1 and TUN002-MON2 were isolated from both the AF and placenta, TUN003-AHA from only the placenta, and TUN004-NEL from only the AF. The four viable strains were not virulent for mice. Genotyping revealed that the four strains were type II strains. This is the first report on isolation and genotyping of T. gondii from Af human samples in tunisia. further studies focused on T. gondii genotyping on a larger number of human cases and on animals in tunisia are needed to improve the knowledge and epidemiology of toxoplasmosis. Toxoplasma infection is one of the most prevalent parasitic disease, caused by the intracellular protozoa, Toxoplasma gondii. This protozoan affects all warm-blooded animals, including humans 1. Humans are infected by the ingestion of Toxoplasma oocysts in water, food or cat feces polluted soil, or toxoplasma cysts present in raw or undercooked meat 2. Congenital toxoplasmosis (CT) may happen following maternal primary infection during pregnancy. Risk of transmission increases with the pregnancy age, while severity of the disease for the fetus decreases. In fact, placenta barrier is more efficient at the first semester of gestation, allowing the passage of parasites in less than 10% of infected pregnant women. However, it becomes more permeable during pregnancy evolution, leading to parasite transmission around 30% and 60-70% of infected pregnant women in the second and third trimester respectively 3. Although, most congenitally infected newborns appear to be healthy at birth, they may develop symptoms until months, years, or even decades later in life. Hydrocephalus, intracranial calcifications, mental retardation, hepatosplenomegaly, and chorioretinitis are classical signs associated with the disease 3. Undiagnosed and untreated patients may expand irreversible lesions, particularly brain calcifications, hydrocephalus, and eye disease 4. Severity of CT may be associated to several factors including parasite genotype, host genetic variability and immune response 5-7. Previously, T. gondii complex was classified into three major lineages designated type I, II and III 8. However, recent studies using various molecular tools and analyzing genetic

First Isolation and Genotyping of Toxoplasma Gondii Strains From Domestic Animals in Tunisia

“…We rstly checked the presence of toxoplasmic DNA in the digestate of seropositive animals by conventional PCR as mentioned in 32 .…”

“…In a recent study, the strains involved in 4 cases of human congenital toxoplasmosis in Monastir area 32 were isolated by mouse bioassay and genotyped using a highly discriminatory method based on the analysis of 15 microsatellite markers 16 . The four strains were found to be of type II lineage, a results more in tune with the diversity of strains expected to be found in a North African country 24 .…”

First isolation and genotyping of Toxoplasma gondii strains from domestic animals in Tunisia

“…In a recent study, the strains involved in 4 cases of human congenital toxoplasmosis in Monastir area 32 were isolated by mouse bioassay and genotyped using a highly discriminatory method based on the analysis of 15 microsatellite markers 16 . The four strains were found to be of type II lineage, a result more in tune with the diversity of strains expected to be found in a North African country 24 .…”

A First Report on Experience in Managing Infants with Congenital Toxoplasmosis in Ethiopia: Case Reports and a Review of Evaluation and Treatment

“…Epidemiologic studies of CT in Africa are represented by case reports from a few countries, appearing in the literature as early as the 1950s [14]. Only a single study from the continent identifies genotype distribution in acute Toxoplasma infections during pregnancy, with Toxoplasma genotype 2 dominating among a Tunisian cohort [15].…”