TOXOPLASMOSIS – A NEGLECTED PARASITIC INFECTION IN INDIA
Compiled & Edited by-Dr.Rk singh
Toxoplasmosis is an infection caused by Toxoplasma gondii, a single-celled parasite that spends most of its life cycle inside cats. Infected cats can pass millions of Toxoplasma parasites daily in its feces and can spread toxoplasmosis easily to almost any other animal that shares the environment with cats. In humans, Toxoplasma parasites usually enter the body by being swallowed. This can happen when people touch their mouth with soiled hands, especially after changing cat litter, or if they eat mutton, beef or venison that has not been cooked thoroughly. The Toxoplasma parasites multiply within cells that line the human digestive tract and can spread to almost any organ in the body, including the brain, skeletal muscles, heart muscle, eyes, lungs and lymph nodes. In healthy people, the body’s immune system eventually stops the spread of Toxoplasma parasites, although some remaining parasites can lie dormant indefinitely in the brain or retina. In people whose immune defenses are weakened because of AIDS, cancer or immunosuppressant medication, a new toxoplasmosis infection may spread out of control and become deadly, or dormant Toxoplasma parasites from an old toxoplasmosis infection may suddenly become active again and cause severe illness. This situation is especially dangerous for people with AIDS. In these people, dormant toxoplasmosis can reactivate and cause a severe brain infection (encephalitis), which can lead to seizures and other neurological problems. If left untreated, the death rate from encephalitis is very high. In addition to being swallowed, Toxoplasma parasites can enter the body through contaminated blood transfusions or through organ transplants taken from infected donors. Also, if a toxoplasmosis infection develops in a pregnant woman, the parasites can cross the placenta and cause toxoplasmosis in the infant. This is called congenital toxoplasmosis. These newborns are at high risk of toxoplasmosis-related eye problems and developmental disabilities.
Up to 90% of cases toxoplasmosis does not cause any symptoms, so the infection often is not recognized. In few cases symptoms develop, e.g. Painless swelling of the lymph nodes, Headache, Malaise (a general sick feeling), Fatigue and Low-grade fever. In rare cases, patients also have experienced muscle aches, sore throat, abdominal pain, rash or neurological symptoms. If a woman develops toxoplasmosis during pregnancy or within six weeks before becoming pregnant, her child may be born with congenital toxoplasmosis. The child often does not have any symptoms at birth. However, a thorough exam usually will uncover signs of infection in the infant’s eyes. Other symptoms in newborns can include unusually small body size, Strabismus, an eye that wanders or is misaligned, or other eye problems, Head size that is unusually large or unusually small, Convulsions, Jaundice, Enlarged lymph nodes, Abnormal bruising, Rash, Developmental delays and, sometimes, mental retardation, In addition, congenital toxoplasmosis increases the risk of fetal death or premature birth.
Up to date in developing countries and in all over the world various chemotherapeutic agents e.g. sulfadiazine (Microsulfon) or clindamycin (Cleocin) are used against toxoplasmosis. These chemotherapeutic agents are still ineffective, toxic and expensive. Immunization is the only efficient and diverse method for a wide range of disease prevention including toxoplasmosis. Therefore development of suitable vaccine is an effective approach to prevent animal as well as human toxoplasmosis. Therefore we developed the recombinant DNA vaccine against Toxoplasmosis. During vaccination trials in mice it was proved that recombinant DNA vaccine give good IgG antibody titer and hence will be a good vaccine against toxoplasmosis in near future.
Reference-On request
