Seropositivity of Toxoplasmosis in Antenatal Women with Bad Obstetric History in a Tertiary-Care Hospital of Andhra Pradesh, India

Article excerpt

INTRODUCTION

Toxoplasmosis is caused by an obligate intracellular protozoan parasite Toxoplasma gondii (1). It is one of the most common parasitic infections of humans and other warm-blooded animals. Approximately one-third of the population are exposed to this parasite (2). Infection in an immunocompetent adult human is usually asymptomatic. Toxoplasmosis is most dangerous for immunocompromised patients and the foetus whose mother is infected during pregnancy (3).

Transmission of the infection to the foetus usually occurs when primary infection is acquired by an immunologically-normal mother during gestation (4). Infected pregnant women are often asymptomatic or many have only mild symptoms, making the diagnosis difficult (1,3). The organism is transmitted haematogenously to the placenta. When this occurs, infection may be transmitted to the foetus transplacentally or during vaginal delivery (4). The risk of congenital toxoplasmosis depends on the timing of the mother's acute infection. The disease is usually severe when acquired in the first trimester, and the severity decreases as the gestational age advances, leading to a mild or an inapparent disease at birth. The different rates of transmission and outcomes are most likely related to placental blood-flow, the virulence and amount of T. gondii acquired, and the immunologic ability of the mother to restrict parasitaemia (4). The overall rate of transmission of maternal infection to the foetus is about 45%. Of these, 60% are subclinical infections, 9% resulting in death of the foetus, and 30% have severe damage (5).

The clinical implications of infection due to Toxoplasma in pregnant patients are manifold. Such patients may have spontaneous abortions, stillbirths, intrauterine growth retardation, preterm deliveries, or foetal anomalies (6).

Various manifestations of congenital infection may occur in the perinatal period. These range from relatively-mild signs, such as prematurity, peripheral retinal scars, sensory deficits, developmental delay, impaired psychomotor performance, and mental retardation to the classic triad of signs consisting of hydrocephalus, intracerebral calcification, and chorioretinitis (4,7). ====== Toxoplasmosis is, thus, a significant risk factor for bad obstetric outcome and a major cause of congenitally-acquired infection, leading to a high degree of intrauterine foetal death and morbidity of the newborn. Treatment of a pregnant woman who acquires infection at any time during pregnancy reduces the chance of congenital infection in her infant by approximately 60% (4). Therefore, early diagnosis of toxoplasmosis is essential to start appropriate treatment on time to reduce the transplacental transmission.

Toxoplasmosis is usually diagnosed by serological tests for Toxoplasma-specific IgM and IgG antibodies. A positive IgG titre is sufficient to establish that a patient has been infected with T. gondii but a negative IgM result virtually rules out a recently-acquired infection, unless sera are tested so early when an antibody response has not yet developed or is undetectable (2).

Against this background, we attempted to determine the extent of seropositivity of toxoplasmosis in antenatal women with bad obstetric history (BOH) and to compare it with that in antenatal women having previous normal obstetric history, attending the antenatal clinic of a tertiary-care hospital in Khammam, Andhra Pradesh, India.

MATERIALS AND METHODS

Study area

This descriptive case-control study was conducted in 2007 at the antenatal clinic of the Mamata General Hospital which is a super-specialty rural hospital attached to the Mamata Medical College, Khammam, Andhra Pradesh, India.

Study subjects

The study group comprised antenatal women of reproductive age with previous BOH, including unfavourable foetal outcome in terms of abortions, intrauterine foetal death, stillbirths, preterm deliveries, unexplained early neonatal death, and congenital anomalies. …