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Viruses passed on to children

Infection of the newborn is still high

The risk of infecting newborn children with diseases transmitted in the womb, at birth, or through the mother’s milk can be minimized when the infection is discovered early in the pregnancy. However, research undertaken by the pediatrician Maria Teresa Zulini da Costa, in the Butantã region of the São Paulo state capital, shows that many pregnant women, many more than expected, arrive already infected at public hospitals for the birth. Her study, financed by FAPESP, reinforces the need for routine blood tests for pregnant women in the public health system. Head of the Neonatal Unit of the Clinical Pediatrics Division of the University Hospital of the University of São Paulo (USP), Maria Teresa points out that peritoneal infections, passed on in the uterus or close to the birth – especially sexually transmitted diseases (STD) or through infected blood or secretions – are growing causes of infant mortality. In her opinion, the city’s basic healthcare system does not carry out proper monitoring of pregnant women to detect these diseases. Her research sought to establish the incidence in pregnant women of the HIV (Aids), HTLV types I and II (associated with leukemia, lymphoma and neurological imbalances), HBV (hepatitis B) and HCV (hepatitis C) viruses. She also undertook a clinical and blood serum analysis of newborn children of infected mothers, to give an indication of the degree of vertical transmission (from mother to child).

The number of cases exceeded all expectations, since the Butantã area is not considered endemic for the diseases being studied. The HIV virus was detected in 0.26% of the pregnant women examined; HTLV I-II was present in 0.13% of cases; 0.32% were actively infected with HBV and 3.5% of the blood serum examinations showed previous infection; for HCV, 0.64% had positive indications although not symptomatic. According to the researcher, as no mother knew in advance that she was a carrier of these diseases, those with HIV at the time of birth, received no treatment with zidovudine (AZT) to lower the chances of infecting the newborn child. One child died at two months of age from septicemia (blood poisoning) probably as a result of infection by HIV. The child’s mother was a carrier of the virus and underwent no treatment in the prenatal period.

Vertical transmission was zero for HTLV and HBV according to the researcher. This result can be attributed to the immediate provision of the necessary treatment at the hospital, by applying the vaccine for the HBV and suspending breast feeding in cases of HTLV I-II. In the other cases, transmission was high: 10% for HCV and 25% for HIV.

The chance of infecting the baby varies. It is high for HIV, if not discovered early in the pregnancy and if the pregnant woman does not receive the right dose of AZT. If the HIV is in the milk, the mother must not breast-feed directly, but it has been shown that pasteurization kills the virus. For HTLV, studies suggest that infection takes place chiefly through the milk and that pasteurization kills this virus too. As for HBV, there is a risk of neonatal infection in between 40% and 90% of the cases. Transmission through the milk is possible, but the immediate application of immunoglobulin and vaccine can avoid infection. Vertical transmission of HCV is still uncertain, but certain precautions are recommended, such as “natural childbirth, which exposes the child less to contact with the mother’s blood”, warns Maria Teresa.

The survey covered 1,540 pregnant women in the Butantã region and took ten months to gather the blood samples and a further 18 months to monitor the babies of infected mothers. The samples from the mothers were taken at the time of birth and those of the children of the infected mothers were taken at 3, 6, and 12 or 24 months of age. Each pregnant woman gave 10 ml of blood. For each positive sample, at least two tests were carried out in confirmation, by examining the DNA or the viral RNA.

If these routine blood tests were carried out for pregnant women in the public health system, as the study suggests, specific and early treatment could be given to those with positive results and to their babies, suspending breast feeding in the case of risk. This and “and giving priority to the basic health system”, says the researcher, “would help a great deal to lower the high infant mortality in our society”.

Maria Teresa Zulini da Costa is a graduate, with a master’s degree and doctorate, of the School of Medicine of the University São Paulo (USP). She has been a professor at USP since 1981 and head of the Neonatal Unit of the Clinical Pediatrics Division of the University Hospital since 1992.
Project: Incidence of HIV, HTLV I-II, HBV and HCV in Pregnant Women in the Butantã Region and Clinical and Blood Serum Assessment of the Newborn Children of Positive Testing Women.
Investment: R$ 28,822.40