Seroprevalence of Toxoplasma gondii in the Iranian pregnant women: A systematic review and meta-analysis

Toxoplasmosis is a common and serious parasitic disease with high prevalence and global distribution
in human and other warm-blooded vertebrates. Though the infection of Toxoplasma gondii is usually
asymptomatic in healthy people, it can lead to severe pathological effects to the fetus of infected women
and immunocompromised patients. So pinpointing the risk factors and control procedures are of important works among these populations. In order to reach this goal, we conducted a systematic review and
meta-analysis to identify the seroprevalence rate of T. gondii infection among Iranian pregnant women
population to achieve a comprehensive explanation of the disease condition in Iran for future use. English
electronic databases (PubMed, Science Direct, Scopus, Ovid and Cochrane) and Persian language databases
(Scientific Information Database, Iran Medex, Magiran and Iran Doc) were searched. Furthermore, the proceedings of Iranian parasitology congresses were explored manually. Our review resulted in a total of 50
publications meeting the inclusion criteria during Jan 1990–June 2015. Totally, 20221 women had been
tested during this period of which 7724 women had seropositivity for IgG. According to results of heterogeneity test, either Der Simonian and Laird’s random-effects method or Mantel-Haenszel’s fixed-effects
method were used to pool the estimations. Weighted overall prevalence of toxoplasmosis in pregnant
women were obtained using random-effects model, which was estimated 41% (95% CI = 36–45%). Also
IgG and IgM antibodies was obtained 38% (95% CI = 34–42%) and 4% (95% CI = 3–5%), respectively. The
highest and the lowest seroprevalence of toxoplasmosis in five geographical zones of Iran were observed
in South 53% (95% CI = 30–77%) and East 33% (95% CI = 23–42%), respectively. In order to detect publication
bias, Egger’s regression test was done which revealed that publication bias might not have a significant
influence on overall prevalence estimate (P = 0.89). Multivariate analysis showed that there’s a statistically significant correlation between toxoplasmosis and two risk factors including “place of residence”
(P = 0.005) and “contact with cat” (P = 0.002). There was no significant difference between toxoplasmosis
and the other surveyed risk factors. It is highly recommended to further study for the aim of better disease
management and developing more efficient diagnostic tests