Truck drivers in Brazil: prevalence of HIV and other sexually transmitted diseases, risk behavior and potential for spread of infection.

OBJECTIVES: To determine the prevalence of HIV and syphilis and related risk behavior in a sample of truck drivers in Santos, Brazil. SUBJECTS AND METHODS: A cross-sectional study was performed of 300 male truck drivers recruited in the port of Santos, Brazil, including a face-to-face interview and blood sampling for HIV and syphilis serology. RESULTS: Of 300 subjects, 4 (1.3%) were positive for HIV, 25 (8.3%) for syphilis by the Venereal Disease Research Laboratory (VDRL) test and 38 (13%) were positive for syphilis by the fluorescent treponemal antibody (absorbed) test (FTA-Abs). Seventy-one per cent had been employed as truck drivers for more than 10 years and 93% lived outside of Santos. Most participants were married (72%); 40% reported having more than one sex partner; 21% reported sex with commercial sex workers; 14% reported sex with girls that they met on the road; 16% had sex with other men's wives; and 3.3% reported sex with men during the past year. The use of rebite, an oral stimulant, was reported by 43% and was associated with being FTA-Abs-positive (P = 0.04). Being HIV-positive was associated with having sex with friends (P = 0.04), partners usually considered 'safe' by truck drivers. Being syphilis-positive (VDRL) was significantly associated with sex with partners also considered as 'safe', namely primary sex partners, steady partners and other men's wives. DISCUSSION: This is the first study to determine HIV and syphilis seroprevalence among truck drivers in South America. Findings confirm that this group has a high potential risk for HIV infection and other sexually transmitted diseases, and thus currently presents an opportunity for prevention.

Social and nutritional influences on the feeding of ring dove squab.

The effects of food deprivation on ring dove squabs' begging and pecking was examined during the period of transition from dependent to independent feeding. Food-deprived squabs begged more, pecked more, and were fed more by their parents than nondeprived squabs. When deprived, young squab primarily beg for food and older squab primarily peck. This difference may arise from the relative efficiencies of the two feeding responses at different ages. Additionally, parental state exerted control over the amount the squab pecked and begged. Parental food deprivation affected squab pecking, probably because hungry parents pecked more themselves and fed squabs less. Squab begging was not affected by parental food deprivation. However, parental separation from squab affected squab begging, as parents previously without squab were more likely to feed begging squab than were parents who were not separated from squab. Parental separation from squab did not affect squab pecking. The changes in the endogenous and exogenous controls of squab feeding allow for a great deal of plasticity in the transition from dependent to independent feeding.

Age differences in the controls of ring doves' pecking.

Three experiments investigated the endogenous and exogenous controls of ring dove pecking. Experiment 1 confirmed that deprivation modulates adult pecking although nondeprived subjects peak at high levels. Experiment 2 determined that the level of pecking in nondeprived birds is modulated by exogenous cues such as the salience of the seed. Experiment 3 analyzed some of the controls of pecking in squabs. Both nondeprived and deprived squabs pecked little on days 12 and 16 of life, but by day 18, deprived squabs pecked significantly more than nondeprived squabs. Squabs inexperienced with deprivation peck less when hungry than squab that have had previous experience with deprivation. The controls of feeding change between day 24 of life and adulthood as exogenous cues did not stimulate nondeprived squab pecking until day 24 of life.