Large Scale Pre-Diagnosis ofToxoplasma GondiiDNA Genotyping by Real-Time PCR on Amniotic Fluid

Genetic characterization of Toxoplasma gondii strains isolated from humans living in İzmir, Türkiye

PURPOSE

Toxoplasma gondii is an obligate intracellular zoonotic parasite that can infect all warm-blooded animals, including humans. Currently, clinical findings of toxoplasmosis are being related to T. gondii strains such as Type I genotype may cause high pathogenicity and Type II genotype causes a milder clinical presentation. We have showed in our previous that Type II genotype is the most frequent strain detected in stray cats and wild birds living in natural life of İzmir. The aim of this study was to assess toxoplasmosis seroprevalence in immunocompromised patients, investigate the presence of T. gondii DNA in their blood samples, and genotype the PCR positive ones.

METHODS

The 42 buffy-coat and serum samples were collected from immunocompromised patients who were from various clinics. Thereafter, Real-Time PCR targeting RE gene of T. gondii was performed with DNA samples obtained from buffy-coat samples. Genotyping was performed by sequencing of GRA6 and GRA7 gene regions of positive DNA samples obtained from tissues of bioassay and PCR positive samples.

RESULTS

According to Real-Time PCR results, T. gondii DNA was detected in 23.8% (10/42) samples. Among these 10 samples, two samples were determined as T. gondii Type II genotype. Anti-Toxoplasma IgG antibodies were detected in 28.57% (12/42) samples.

CONCLUSIONS

Overall, the detection of Type II genotype in humans in İzmir province suggested that T. gondii infection in humans, stray cats, and wild animals may be associated to each other in terms of transmission.

Evaluation of Serological and Molecular Tests Used for the Identification of Toxoplasma gondii Infection in Patients Treated in an Ophthalmology Clinic of a Public Health Service in São Paulo State, Brazil

Ocular toxoplasmosis is one of the most common complications caused by the infection with the parasite Toxoplasma gondii. The risk of developing eye lesions and impaired vision is considered higher in Brazil than other countries. The clinical diagnosis is difficult and the use of sensitive and specific laboratorial methods can aid to the correct diagnosis of this infection. We compared serological methods ELISA and ELFA, and molecular cPCR, Nested PCR and qPCR for the diagnosis of T. gondii infection in groups of patients clinically evaluated with ocular diseases non-toxoplasma related (G1 = 185) and with lesions caused by toxoplasmosis (G2 = 164) in an Ophthalmology clinic in Brazil. Results were compared by the Kappa index, and sensitivity (S), specificity (E), positive predictive value (PPV), and negative (NPV) were calculated. Serologic methods were in agreement with ELISA more sensitive and ELFA more specific to characterize the acute and chronic infections while molecular methods were discrepant where qPCR presented higher sensitivity, however, lower specificity when compared to cPCR and Nested PCR.

A review of toxoplasmosis in humans and animals in Turkey

Infections by the protozoan parasite Toxoplasma gondii are widely prevalent in humans and animals in Turkey but little is known of the burden of their clinical toxoplasmosis. Many early papers on toxoplasmosis in Turkey were published in Turkish and often not available widely. Here, we review prevalence, clinical spectrum, epidemiology and diagnosis of T. gondii in humans and animals in Turkey. This knowledge should be useful to biologists, public health workers, veterinarians and physicians. Although one-third of the human population in Turkey is seropositive, the rate of congenital toxoplasmosis is unknown and no information is available in children 12 years old or younger. One large outbreak of acute toxoplasmosis has been reported in 14–18-year old school children in Turkey. An alarming rate (36%) of T. gondii tissue cysts were reported in tissues of sheep and water buffalo meats destined for human consumption; these reports require verification. Genetically, T. gondii strains from domestic cats and wild birds in Turkey were generally classical type II and III, like those prevalent in Europe. A separate genotype, Type 1 Africa, was isolated from two congenitally infected children and a domestic cat in Turkey.

Evaluation of serological and molecular tests used to identify Toxoplasma gondii infection in pregnant women attended in a public health service in São Paulo state, Brazil

Toxoplasmosis during pregnancy can have severe consequences. The use of sensitive and specific serological and molecular methods is extremely important for the correct diagnosis of the disease. We compared the ELISA and ELFA serological methods, conventional PCR (cPCR), Nested PCR and quantitative PCR (qPCR) in the diagnosis of Toxoplasma gondii infection in pregnant women without clinical suspicion of toxoplasmosis (G1=94) and with clinical suspicion of toxoplasmosis (G2=53). The results were compared using the Kappa index, and the sensitivity, specificity, positive predictive value and negative predictive value were calculated. The results of the serological methods showed concordance between the ELISA and ELFA methods even though ELFA identified more positive cases than ELISA. Molecular methods were discrepant with cPCR using B22/23 primers having greater sensitivity and lower specificity compared to the other molecular methods.