Infants who eat food that has been prechewed by an HIV-positive caregiver may be at risk for HIV infection, a series of U.S. case reports suggests.1 Researchers identified three cases in which young, HIV-negative children were infected with the virus after frequent feedings of premasticated food; in each case, no other likely routes of transmission were present. Although the investigators believe that such transmission is likely rare, the findings raise concerns because prechewing food is a common practice in many developed and developing countries.
The investigators studied two cases in Miami and one in Memphis. In all three instances, health care providers had interviewed parents and relatives, reviewed medical histories and collected blood samples to establish that an infant born HIV-negative who was given prechewed food by an HIV-infected family member eventually tested positive for the virus.
The first case concerned a 15-month-old Miami boy who had been fed prechewed food by his recently deceased, HIV-positive great-aunt for about five months. The boy’s mother had not known that her aunt had HIV, although she had noticed that her aunt’s gums sometimes bled into the food she gave the boy. The infant was tested for HIV following a pediatrician visit for recurrent diarrhea and ear infection. Because the test was positive, the boy and his mother, both previously HIV-negative, were subsequently tested multiple times using HIV-1 antibody tests and Western blots; on each occasion, he tested positive for HIV, while she remained negative.
Because the great-aunt had died and no blood samples from her were available, the researchers were unable to confirm that her strain of HIV was genetically identical to the boy’s. Researchers did test a sample from the great-aunt’s sexual partner, an HIV-infected intravenous drug user, and found that his HIV strain was not related to the boy’s; this did not exclude the great-aunt as the source of infection, however, as she could have become infected from some other source.
The second case, which occurred in 1995 in the same city, involved a child born to an HIV-positive mother. Despite a lack of perinatal prophylactic treatment, the child had tested negative for the virus at 20 and 21 months of age, and showed no signs of immunosuppression. By 39 months, however, the child had developed medical problems consistent with possible HIV infection: Tests revealed the presence of HIV and severe immunosuppression. A phylogenetic analysis of virus samples confirmed that mother-to-child transmission had likely occurred. The mother reported that she had fed the child premasticated food but did not remember whether she had good oral health at the time.
The third case, which prompted the researchers’ investigation, took place in Memphis in 2004. A nine-month-old girl born to an HIV-infected mother developed a variety of health issues and tested positive for HIV. Because of the mother’s HIV status, the infant had received prophylactic antiretroviral medication for six weeks following delivery and had been tested for HIV several times during her first four months. All of these earlier tests for HIV had been negative. She had not been breast-fed; however, the mother, who occasionally had bleeding gums and had taken her HIV medication inconsistently during and after the pregnancy, had begun giving her daughter prechewed food when the child was about four months old. Phylogenetic analysis provided strong evidence that the mother had passed HIV on to her infant.
In this case, as in the previous two, interviews with caregivers and physical examinations failed to uncover any other likely means of transmission, such as injury, transfusion or sexual abuse leading the investigators to conclude that the infants, who were teething or suffering oral illness, were infected via prechewed food containing blood from an HIV-positive parent or relative.
The researchers note that prechewing food may be more common than health care providers realize. Although data on this topic are limited, 11% of mothers in a U.S. survey reported having fed prechewed food to their 10-month-old infant; three-fifths of respondents in a Chinese study said they had fed their child prechewed food, and one-fifth had done so regularly.
Although mother-to-child transmission of other infectious microorganisms has been associated with prechewed food in some parts of the developing world, such transmission of HIV is "probably rare," the researchers contend, as it requires "a convergence of risk factors affecting both the caregiver and the child." Detecting any cases that do occur is difficult, particularly in developing countries, because such transmission may be attributed to breast-feeding. They caution health care providers to take cultural beliefs and available resources into consideration before counseling HIV-positive parents and relatives against prechewing food, but emphasize that "it is crucial to educate caregivers who are infected with HIV about prechewing"—especially those who have active bleeding in the mouth—"because they may be unaware of its potential health risks.—S. Ramashwar
REFERENCE
1. Gaur AH et al., Practice of feeding premasticated food to infants: a potential risk factor for HIV transmission, Pediatrics, 2009, 124(2):658–666.