Table 3.
Logistic multiple regression analysis of the models that regressed the proportion of candidate children who acquired Trypanosoma cruzi infection (the response variable) on the domiciliary abundance of Triatoma infestans, the abundance of bugs infected with T. cruzi per person-hour, the number or proportion of infected dogs or cats, the presence of at least one infected dog or child, the human blood index, and the household effects parameter (the predictor variables), Amamá, Argentina, 1988–1992*
| Data | Terms in model† | Deviance | Degrees of freedom | Likelihood ratio statistic | P |
|---|---|---|---|---|---|
| 1988–1989, Intercept | 42.72 | 0 | |||
| Bug abundance in 1988 | 38.03 | 1 | 4.69 | 0.03 | |
| + % infected bugs | 36.29 | 1 | 1.74 | 0.19 | |
| + at least 1 dog positive | 33.51 | 1 | 4.52 | 0.03 | |
| Maximum bug abundance in 1988–1989 | 37.39 | 1 | 5.33 | 0.02 | |
| + % infected bugs | 35.72 | 1 | 1.67 | 0.20 | |
| + at least 1 dog positive | 33.18 | 1 | 4.21 | 0.04 | |
| + at least 1 child positive | 36.81 | 1 | 0.57 | 0.45 | |
| Maximum infected bug abundance in 1988–1989 | 32.70 | 1 | 10.02 | 0.002 | |
| + at least 1 dog positive | 30.86 | 1 | 1.85 | 0.17 | |
| + at least 1 child positive | 32.15 | 1 | 0.55 | 0.46 | |
| 1992, Intercept | 42.72 | 0 | |||
| Bug abundance | 30.79 | 1 | 11.93 | < 0.001 | |
| + % infected bugs | 30.78 | 1 | 0.01 | 0.92 | |
| + % dogs positive | 26.46 | 1 | 4.33 | 0.04 | |
| Infected bug abundance | 31.66 | 1 | 11.06 | < 0.001 | |
| + % dogs positive | 25.44 | 1 | 6.22 | 0.01 | |
| + at least 1 child positive in 1989 | 31.60 | 1 | 0.06 | 0.81 | |
Addition of child age and sex, number of domestic hosts, human or chicken blood indices, and the random effects parameter to every model was not significant. This includes cases with no missing data for the variables in the model.
Predictor variables preceded by a + sign were added separately and independently, not cumulatively with others preceded by a + sign, to the above predictor variable not preceded by a + sign; for example, Bug abundance in 1988 alone had a deviance of 38.03, Bug abundance in 1988 plus % infected bugs had a deviance of 36.29, and Bug abundance in 1988 plus “at least 1 dog positive” (not including “% infected bugs”) had a deviance of 33.51.