Circannual rhythm in human sperm count revealed by serially independent sampling.

Sperm concentration and total sperm counts from single semen and samples from each of 4435 patients requesting vasectomy between September 1972 and December 1977 were analyzed for circannual (about 1 year) rhythmicity. Although large temporal variations were found both between years and within years, a trend was noted for higher sperm concentration during the winter than during the summer. When the entire series of data were analyzed by months, a strong circannual pattern was apparent, with the highest sperm counts between February and March and the lowest counts during September. To the authors' knowledge, this is the first report of a circannual rhythm in human sperm concentration and total sperm count. The data must be considered preliminary, but if confirmed by other investigators studying comparable populations, the influence on clinical investigations will be profound.

Prevention of traveler's diarrhea (emporiatric enteritis). Prophylactic administration of subsalicylate bismuth).

The efficacy of a daily dosage regimen of subsalicylate bismuth in preventing or reducing the severity of diarrhea among young healthy adults was evaluated in a double-blind, randomized, placebo-controlled trial. Diarrhea developed in 14 (23%) of 62 students receiving subsalicylate bismuth compared with 40 (61%) of 66 students taking a placebo. The protective effect of subsalicylate bismuth was apparent within a day or two of the study onset and became more obvious as the number of days at risk increased. The students treated with subsalicylate bismuth experienced fewer intestinal complaints and were less likely to pass soft or watery stools of any number. Once diarrhea occurred, enteropathogens were less commonly identified in stools of students receiving subsalicylate bismuth (33%) compared with placebo (71%). Subsalicylate bismuth was well tolerated by students during the 21-day trial.

Detection and characterization of colonization factor of enterotoxigenic Escherichia coli isolated from adults with diarrhea.

The fimbriate colonization factor antigen (CEA) of Escherichia coli strain H-1047 was isolated and used to prepare anti-CFA antiserum. Enterotoxigenic E. coli (ETEC) isolated from 29 adults with diarrhea acquired in Mexico were examined for CFA by using this serum. Retrospectively, it was found that ETEC possessing the H-10407-type CFA were isolated from 25 (86%) of these diarrhea cases as compared with 2 of 11 (18%) from asymptomatic controls from whom ETEC had been isolated. CFA was found onE. coli of various serotypes, as demonstrated by bacterial agglutination by the anti-CFA serum. Heat treating the cells at 65 degress C for 1 h prevented the agglutination. CFA-positive strains did not react with anti-CFA serum when the cultures were grown at a low incubation temperature (18 degrees C). E. coli isolates identified serologically as CFA positive were shown to adhere to the intestinal villous surfaces of infant rabbits. By the indirect immunofluorescence technique, it was found that adhesion occurred preferentially in the upper 20 cm of the small intestine. Also, the ability or inability of various isolates to adhere to intestinal mucosa in vivo correlated with the presence or absence of fimbriae on the cells when grown in vitro. Agglutinability with anti-CFA serum, fimbriae, and adhesiveness were spontaneously lost by many isolates after laboratory passage in a manner previously described with E. coli H-10407. These observations suggest that the H-10407-type CFA plays a role in the virulence of ETEC possessing this antigen.

Location of food consumption and travelers' diarrhea.

Daily food histories for one month were obtained in summer, 1975, from students attending a Mexican university to determine the influence of food consumption on the development and etiology of diarrhea. In newly-arrived students from the U.S. who ate half or more of their meals in the school cafeteria and public restaurants there were significant increases in diarrhea (p less than 0.005); shigella infection (p less than 0.05) and toxigenic E. coli infection (p less than 0.025) compared to the students eating a comparable number of meals in private homes. In the summer U.S. students there was also an association of diarrhea and eating from street vendors (p less than 0.05). In full-time U.S. students who had lived in Mexico a year or longer as well as in Latin American students a relationship between location of meals and occurrence of enteric disease was not apparent. High numbers of enteric bacteria were recovered from food from the school's cafeteria, public restaurants, street vendors and small grocery stores. Shigella were isolated from cooked and uncooked hamburger patties from the school cafeteria. Four shigella carriers were found among kitchen personnel at the school. This study demonstrates that food serves as a major vehicle through which travelers' diarrhea occurs.