Seroprevalence of the enteroaggregative Escherichia coli virulence factor dispersin among USA travellers to Cuernavaca, Mexico: a pilot study.

This pilot study examined the change in the seroprevalence of the enteroaggregative Escherichia coli (EAEC) virulence factor dispersin in USA students during a short stay in Cuernavaca, Mexico, between June and August 2004. One hundred and ninety-five students provided paired serum samples - one on arrival to Mexico (pre-serum) and a second on departure from Mexico (post-serum) after a mean stay of 19 days. Serum samples were tested for IgG antibody to a recombinant purified dispersin protein by ELISA. For all travellers, with and without diarrhoea, the mean+/-sd pre-serum absorbance value (read at 450 and 570 nm) was 0.340+/-0.212 and the mean post-serum value was 0.513+/-0.316 (P<0.00001). Both travellers who developed diarrhoea and those who did not develop diarrhoea had an increase in IgG antibody to dispersin from the time of arrival to the time of departure from Cuernavaca (diarrhoea group 0.323+/-0.197 to 0.501+/-0.311, P<0.00001, and the asymptomatic group 0.354+/-0.224 to 0.525+/-0.321, P<0.00001). The pre-serum absorbance value (read at 450 and 570 nm) for IgG antibody to dispersin was not associated with protection against the development of diarrhoeal illness. These results indicate that USA travellers to Mexico show seroconversion for the EAEC virulence factor dispersin. Further studies are needed to characterize in more detail the host clinical and immunological responses to the dispersin protein.

The role of diet in the treatment of travelers' diarrhea: a pilot study.

A pilot study was performed to compare the effects of a restricted physiologic diet in 48 subjects with those of an unrestricted diet in 57 subjects on the duration and symptoms of acute travelers' diarrhea among US adults being treated with an antimicrobial agent in Mexico. Restricted physiologic diet was defined as the avoidance of certain foods during diarrheal illness, as specified in limited published literature. The mean duration of diarrhea (37 vs. 33 h) and clinical symptoms were similar between those practicing the restricted diet and those practicing unrestricted diets. These results suggest that restricting diet during treatment of travelers' diarrhea with an antimicrobial agent is not associated with improvement of clinical symptoms or with decreased duration of diarrhea. However, a much higher number of subjects would need to be studied to prove this point statistically.

Vaccines and immunotherapies for the prevention of infectious diseases having cutaneous manifestations

Although the development of antimicrobial drugs has advanced rapidly in the past several years, such agents act against only certain groups of microbes and are associated with increasing rates of resistance. These limitations of treatment force physicians to continue to rely on prevention, which is more effective and cost-effective than therapy. From the use of the smallpox vaccine by Jenner in the 1700s to the current concerns about biologic warfare, the technology for vaccine development has seen numerous advances. The currently available vaccines for viral illnesses include Dryvax for smallpox; the combination measles, mumps, and rubella vaccine; inactivated vaccine for hepatitis A; plasma-derived vaccine for hepatitis B; and the live attenuated Oka strain vaccine for varicella zoster. Vaccines available against bacterial illnesses include those for anthrax, Haemophilus influenzae, and Neisseria meningitidis. Currently in development for both prophylactic and therapeutic purposes are vaccines for HIV, herpes simplex virus, and human papillomavirus. Other vaccines being investigated for prevention are those for cytomegalovirus, respiratory syncytial virus, parainfluenza virus, hepatitis C, and dengue fever, among many others. Fungal and protozoan diseases are also subjects of vaccine research. Among immunoglobulins approved for prophylactic and therapeutic use are those against cytomegalovirus, hepatitis A and B, measles, rabies, and tetanus. With this progress, it is hoped that effective vaccines soon will be developed for many more infectious diseases with cutaneous manifestations.Learning objective At the completion of this learning activity, participants should be familiar with the current and experimental vaccines and immunotherapies for infectious diseases with cutaneous manifestations.

United States male students who heavily consume alcohol in Mexico are at greater risk of travelers' diarrhea than their female counterparts.

BACKGROUND: The relationship between alcohol consumption and travelers' diarrhea has not been well studied. METHODS: A cohort of US college students (n=171), who attended 2001 or 2002 summer educational sessions in Guadalajara, Mexico, were followed prospectively to examine the frequency of alcohol consumption and the development of travelers' diarrhea. RESULTS: More male students reported consuming >5 drinks/day of drinking while in Mexico compared to female students (p <.001). Males who consumed >5 drinks/day of drinking while in Mexico were more likely to develop diarrhea than their female counterparts who drank the same amount (79% vs. 46%; p=.035). No association was found between the development of travelers' diarrhea and the consumption of fewer than 5 drinks per day in Mexico. Non-drinkers accounted for only 8% of the population and had a relatively high attack rate of diarrhea (69%). CONCLUSIONS: This study suggests that males who drink heavily are at high risk for developing travelers' diarrhea and may be a group of people to target for education about the moderation of use of alcohol while traveling. Nondrinkers also deserve further study in larger numbers to confirm an apparently high attack rate of diarrhea and to explore what risk factors might be involved.

Association of virulence factor-positive and -negative enteroaggregative Escherichia coli and occurrence of clinical illness in travelers from the United States to Mexico.

The objective of the study was to determine if the presence or absence of virulence factor-positive and -negative enteroaggregative Escherichia coli (EAEC) determined the occurrence of illness or sub-clinical EAEC infection in travelers from the United States to Mexico. Sixty-five newly arrived college students from the United States submitted weekly stool samples for a four-week period of time. Among EAEC-infected subjects, diarrhea occurred in those with a defined virulence factor with the following frequency: aggA, 5 of 15 (33%); aggR, 3 of 11 (27%); aafA, 3 of 8 (38%); and aspU, 1 of 6 (17%). Twenty-two of 31 students (71%) had two or more EAEC infections. After the initial EAEC infection, only 4 (11%) of 31 students had a subsequent symptomatic EAEC infection. Our study suggests that clinical illness by EAEC is not explained by presence of a defined EAEC virulence factors, and we provide suggestive evidence that EAEC infection protects against future symptomatic infection.