Seroprevalence and risk factors of Toxoplasma gondii infection in pregnant women from Bobo Dioulasso, Burkina Faso

Toxoplasmosis is one of the common worldwide parasitic zoonosis, caused by an obligate intracellular protozoan parasite Toxoplasma gondii [1]. Felines are the only definitive host while all other warm-blooded animals including humans are intermediate hosts for the parasite [2]. T. gondii is commonly transmitted to humans by accidental ingestion of oocyst stage of the parasite in water, food or soil contaminated with cat’s faeces, or by eating raw or undercooked meat containing oocysts [2, 3]. It can also be transmitted congenitally during pregnancy [4]. In addition, other infectious pathways include blood transfusion, and organs transplantation [5]. Toxoplasmosis is more common in areas with tropical and very humid climates which are favorable conditions for the maintenance and dissemination of the oocysts [6].

Toxoplasmosis is a major public health problem in the world. Indeed, it is estimated that about one third of the World’s population is infected with T. gondii. Although usually asymptomatic, it can result during pregnancy in fetal and neonatal death or various congenital defects [7] especially when the congenital infection occurs during the first trimester due to acute infection during pregnancy.

In Africa, the seroprevalence of T. gondii during pregnancy is generally as high as 80% [3, 8]. Moreover, presence of domestic cat at home [3], contact with cat and gardening soil [8] were found to be the main risk factor toxoplasmosis during pregnancy.

In Burkina Faso, the seroprevalence of toxoplasmosis during pregnancy have been poorly reported [9‐11] and none of those previous reports had assessed risk factors for toxoplasmosis. This study sought therefore to determine the seroprevalence of T. gondii and to identify the potential risks factors associated with of T. gondii infection among pregnant women following ANC services at Bobo Dioulasso, the second largest city of Burkina Faso.

The prevalence of anti-T. gondii IgG antibodies observed in this study (31.1%) was consistent with previous findings reported in pregnant women from urban areas of Burkina Faso and ranged from 28.3% to 31% [9‐11]. Our result was lower than those reported in Ghana (92.5%) [15] and in Ethiopia (higher than 68%) [3, 8, 16, 17]. However, lower seroprevalence of T. gondii was reported in many European countries and the United States of America [18]. Such seroprevalence variations could be due to differences in climatic conditions (dry climate, rainfall, temperature, soil type, altitude) and mothers’ characteristics such as management of cats, educational level, hygienic practice and feeding habit [3, 8, 17]. Furthermore, differences in serological methods used and the sensitivity difference could explain such discrepancy [8, 17].

All the pregnant women were positive for IgG anti-bodies exclusively suggesting either past infection or acquired immunity. Thus, they were not likely able to infect their fetus outside a context of high immunosuppression [6, 19].

In this study high education level, being urban resident and the consumption of meat combination (pork + beef + mutton + wild meat + poultry) were identified as possible risk factors associated with T. gondii infection. Women with high education level were more likely to consume meat combination (pork + beef + mutton + wild meat + poultry) probably due to their high income and were therefore more exposed to T. gondii infection. Our findings suggest the need for preventive measures such as education of pregnant women about the transmission routes and prevention methods of toxoplasmosis at ANC clinics. However, a previous study in Ethiopia showed that women who cannot read and write were 5 times more likely to acquire T. gondii infection than those who had tertiary level of education [17]. In Brazil, pregnant women with low educational status had higher seroprevalence of T. gondii [20]. Moreover, reports from Netherlands and USA, showed that the seroprevalence of toxoplasmosis increases when the level of education decreases [6, 21].

Furthermore, the association between seroprevalence of T. gondii and urban residence of Bobo-Dioulasso town could be explained by insalubrity due to the demographic pressure in that town and dilapidation of water pipelines. Both factors are known to favor the survival of oocysts and to maintain a high prevalence of T. gondii infection [22‐24]. Our results suggest the need for conducting further studies to better understand to what extend urban residence plays a role in the epidemiology of toxoplasmosis in Bobo-Dioulasso town.

In our study pregnant women consuming meat combination (pork + beef + mutton + wild meat + poultry) were significantly at greater risk of toxoplasmosis. This could be due to differences in the seroprevalence of T. gondii in the type of animals consumed in that town. Indeed, we previously reported a seroprevalence of 14.3% and 60% for both bovine and ovine toxoplasmosis in Bobo-Dioulasso town during the same period of the study [25, 26]. Altogether our data highlight the need for further studies aiming to assess the seroprevalence of T. gondii in domestic animals such pigs and poultry.

We do acknowledge some limitations to our study. First, risk factor assessment was done based on study participants’ response which may suffer from recall bias. Second, since this study was heath centers based study, it may not represent the general population.

Toxoplasmosis is frequent in pregnant women and studies that show incidence of congenital infection among the neonates have to be done to introduce routine antenatal screening program to control congenital toxoplasmosis. Education level, being urban resident and the consumption of meat combination were identified as possible risk factors associated with T. gondii infection. There is the need for preventive measures such as education of pregnant women about the transmission routes and prevention methods of toxoplasmosis at ANC clinics. Further studies aiming to assess the seroprevalence of T. gondii in domestic animals are warranted.