Seroprevalence of Toxoplasmosis in Pregnant Women in Urmia , Iran

Background: Toxoplasma gondii is an obligate intracellular parasitic protozoan, capable of infecting a wide range of warm-blooded hosts, including humans. Infection with T. gondii can be life threatening in immunocompromised people. Moreover, infection with T. gondii during pregnancy can lead to severe problems for fetus. Objectives: This study was performed to evaluate the seroepidemiological status of toxoplasmosis in pregnant women in Urmia,


Background
Toxoplasma gondii is an obligate intracellular parasitic protozoan, capable of infecting a wide range of warmblooded hosts, including humans.Infection with T. gondii has very different clinical signs in human, such as abortion and congenital eye disease (1).Toxoplasmosis is caused by the consumption of contaminated meat or being in contact or touch with cats which may pass oocytes through their feces (2).
The diagnosis of toxoplasmosis is extremely important in four groups of people: pregnant women who are infected during pregnancy, congenitally infected newborns, patients with chorioretinitis, and also immunocompromised people (3).
Therefore, if the mother is involved in infection during pregnancy, the infection can be transferred to the fetus.However, if the mother is infected before pregnancy, the infection will not be transferred to the fetus and the mother will acquire immunity against future infections of Toxoplasma.Several studies have been conducted on seroepidemiology of toxoplasmosis on pregnant women in Iran and other countries.The mean prevalence of toxoplasmosis in different districts of Iran has been reported about 35%.The reports indicate that the prevalence rate changes in different areas (4).

Objectives
There is very limited information about the rate of toxoplasmosis in pregnant women of west Azerbaijan, Iran.Therefore, we performed this study because of the need to determine the seroprevalence of T. gondii among pregnant women in Urmia, west Azerbaijan, and offer effective practices that to prevent toxoplasmosis in this group of people.Additionally, to perform a novel and more effective strategy for preventing congenital toxoplasmosis, latest seroepidemiological statics will be needed.

Materials and Methods
This study was performed from March to June 2014 in Urmia, north-west of Iran.In this study, the sample size was calculated considering a prevalence of 32%, a degree of precision of 4 (d = 0.04) and 95% confidence interval.In the limited time of sampling, we could collect 156 blood samples of pregnant women of our city.Our sampling was among pregnant women who were referred to health centers in Urmia for routine exams of pregnancy.The women filled a questionnaire containing socio-demographic questions.Blood samples were collected and sera were separated by blood centrifugation at 2500 -3000 rpm for 5 -8 minutes and frozen at -20°C until use.
Anti -T.gondii IgG and IgM antibodies were tested with a commercial ELISA kit (Abcam, United Kingdom) according to the manufacturer's instructions and the absorbance was read at 450 nm using an automatic ELISA reader.Three different concentrations of standards were used to ensure that the kits and our procedures were reliable.The chisquared test was used to analyze the data in SPSS software.

Results
A total of 156 sera samples obtained from pregnant women were tested for anti -T.gondii-specific IgM and IgG antibodies.The mean age of the women was 19.68 years.IgG and IgM anti-Toxoplasma antibodies were positive in 44/156 cases (28.2%) and 4/156 cases (2.56%), respectively.No significant relationship was seen between toxoplasmosis and other tested factors.

Discussion
This study revealed a seroprevalence of 28.2% (44/156) and 2.56% (4/156) for IgG and IgM antibodies against T. gondii in pregnant women in Urmia city, respectively.Our study showed that 28.2% of pregnant women were seropositive.This prevalence rate was less than the previous studies in Iran and geographically similar countries.However, IgM positivity rate was highly close to the results of other similar studies in Iran.For example, in a seroprevalence study on T. gondii infection among pregnant women in Mashhad, Iran, 144 of 419 cases were reported positive for Toxoplasma IgG antibodies, indicating a seroprevalence of 34.4% (5).The rate of seroprevalence of Toxoplasma IgG antibodies in Tehran, Iran was reported 42.2% in a 35 -50 age group (6).
In another study in Ilam, Iran, of 553 pregnant women, 247 were positive for T. gondii IgG antibodies and 306 were negative.The mean age of women was 21 and the seropositivity rate of latent T. gondii infection was 44.8% (7).
Hajsoleimani et al. showed that anti -Toxoplasma IgM and IgG were positive in 1.4% and 37.2% of pregnant women, respectively.In their study, there was no significant relationship between the seroprevalence of T. gondii infection and socio-demographic factors (8).
In Zahedan, 30.8% of sera were positive for anti -Toxoplasma IgG and the highest rate of infection was found in uneducated women (44.4%).Sharifi et al. found a significant correlation between education status, unwashed/unpeeled vegetables and seropositivity (P < 0.05) (9).
In a similar study in Hamadan performed by Maghsood et al. from 350 pregnant women 30% had anti -Toxoplasma IgG and 2.9% were positive for IgM (10).
The seroprevalence rate of infection in the world is also very different.The prevalence of infection in other countries includes 42.47% in Malaysia (17), 30.1% in Turkey ( 18), and 7.01% in China (19).
According to our study, a considerable number of pregnant women in our area were susceptible to infection of acute T. gondii during pregnancy.Therefore, toxoplasmosis regular screening program in pregnancy and pre-marriage tests are strongly recommended.Considering preventive methods such as avoiding consuming raw or undercooked meat and keeping cats away from home could also be very helpful.