Background: Previous case-control studies of neonatal tetanus (NNT) in the North West Frontier Province of Pakistan indicated that clarified butter (ghee) applied to the umbilical wound of newborns was a significant risk factor for NNT. However, the mechanisms underlying the risk remained undisclosed.
Methods: A hospital-based case-control study was undertaken to evaluate further ghee and other factors possibly associated with risk of NNT. Mothers of several recent ghee-associated cases were visited in their homes, asked to simulate the procedures used in preparing the ghee, and samples of ghee were collected for culture.
Results: Topical application of ghee to the umbilical wound was again shown to pose a significant risk for NNT. In-use contamination of ghee was documented as mothers repeatedly heated and manipulated samples of ghee set aside in special containers for this purpose. Ghee was usually applied to the umbilical wound of the baby several times each day for the first few days of life. Mothers of cases were again confirmed to be substantially more likely to report prior NNT cases than mothers of controls.
Conclusions: Educational interventions to reduce umbilical ghee use or to wash hands before each manipulation might reduce the risk of NNT in babies exposed to ghee who are born to non-immunized mothers. Increased efforts to immunize women of childbearing age with tetanus toxoid are also needed, with special priority for mothers known to have been associated with a previous NNT case. Topical antibiotics should be further evaluated for protective effects in non-immunized mothers.
PIP: Previous investigations in Pakistan revealed that the application of ghee (clarified butter) to umbilical wounds is a risk factor for neonatal tetanus (NNT), but the underlying mechanisms remained unknown because multiple cultures of ghee obtained from relevant households failed to culture Clostridium tetani. This study used a case-control approach to continue the evaluation of the risk of ghee applications through within-household observations of patterns of use of ghee and further microbiological tests. 100 physician-diagnosed cases who were hospitalized with NNT from September 1990 to January 1991 were compared with 300 controls matched as nearly as possible in age and sex. Data collected through questionnaires were submitted to descriptive analyses, matched analysis with single variables, stratified analysis, and other tests of statistical significance. Conditional logistic regression and Pearson correlation coefficients were also assessed. The only significant factors discovered were delivery by an academically trained attendant (which had a protective effect against NNT) and use of ghee on the umbilical wound (which was a risk factor for NNT). The household investigations revealed that the ghee for use on the newborn is kept in a separate container than that for general household use. The newborn's ghee is reheated and manipulated frequently by the mother. 25% of the samples from the secondary pots of ghee were contaminated. Heating is likely to activate rather than kill the spore-bearing bacteria which causes NNT. The influence of maternal practices is also seen in the fact that the incidence of NNT among previous births was statistically higher for mothers of cases than for mothers of controls. Since use of ghee is unlikely to be abandoned for sociocultural reasons, the added use of topical antibiotics should be evaluated for their impact on the risk factor posed by ghee. Also, special priority should be paid to the immunization of mothers of NNT cases.