Protective practices and respiratory illness among US travelers to the 2009 Hajj

BACKGROUND

All mass gatherings can place travelers at risk for infectious diseases, but the size and density of the annual Hajj pilgrimage to the Kingdom of Saudi Arabia (KSA) present important public health and infection control challenges. This survey of protective practices and respiratory illness among US travelers to the 2009 Hajj was designed to evaluate whether recommended behavioral interventions (hand hygiene, wearing a face mask, cough etiquette, social distancing, and contact avoidance) were effective at mitigating illness among travelers during the 2009 Hajj.

METHODS

US residents from Minnesota and Michigan completed anonymous surveys prior to and following travel to the 2009 Hajj. Surveys assessed demographics, knowledge, attitudes, and practices (KAP) related to influenza A(H1N1), vaccination, health-seeking behaviors, sources of health information, protective behaviors during the Hajj, and respiratory illness during and immediately after the Hajj.

RESULTS

Pre- and post-travel surveys were completed by 186 participants. Respiratory illness was reported by 76 (41.3%) respondents; 144 (77.4%) reported engaging in recommended protective behaviors during the Hajj. Reduced risk of respiratory illness was associated with practicing social distancing, hand hygiene, and contact avoidance. Pilgrims who reported practicing more recommended protective measures during the Hajj reported either less occurrence or shorter duration of respiratory illness. Noticing influenza A(H1N1) health messages during the Hajj was associated with more protective measures and with shorter duration of respiratory illness.

CONCLUSIONS

Recommended protective behaviors were associated with less respiratory illness among US travelers to the 2009 Hajj. Influenza A(H1N1) communication and education in KSA during the Hajj may also have been an effective component of efforts to mitigate illness. Evaluations of communication efforts and preventive measures are important in developing evidence-based public health plans to prevent and mitigate disease outbreaks at the Hajj and other mass gatherings.

Prevalence and incidence of Entamoeba histolytica infection in South Africa and Egypt

There are little data on the true prevalence and incidence of Entamoeba histolytica infection in Africa. This is due to the inability, historically, to differentiate Entamoeba histolytica from the more common, but non-pathogenic, Entamoeba dispar. In addition, newer studies have demonstrated that the previous gold standard, culture with zymodeme analysis, is insensitive in detecting the presence of infection, especially when compared to PCR. Recent published articles as well as data from the authors' previous work are reviewed and summarized to elucidate what is known about prevalence and incidence of Entamoeba histolytica in Africa. The majority of data on asymptomatic infection are published from South Africa, Egypt and Cote d'Ivoire. Egypt has high rates of asymptomatic infection detected in the stool (>21%), whereas South Africa and Cote d'Ivoire rates range between 0 and 2%. Seroprevalence estimates the rate of recent infection, because anti-amebic antibodies generally persist for <5 years. Seropositivity rates (IgG, IgA) range from approximately 10 to 20%, indicating recent infection in this proportion of the population. Entamoeba histolytica infects a significant proportion of many populations of Africa; however, little data are currently available to indicate true prevalence and incidence. Further studies are needed to determine the burden of infection and disease in Africa.

A recombinant cysteine-rich section of the Entamoeba histolytica galactose-inhibitable lectin is efficacious as a subunit vaccine in the gerbil model of amebic liver abscess

The 170-kDa subunit of the galactose-inhibitable adherence lectin of Entamoeba histolytica mediates attachment to colonic mucins and host cells. The DNA fragment encoding the 170-kDa subunit was produced by polymerase chain reaction (PCR) and divided into four sections by restriction endonucleases. The third section (designated LC3, base pairs 2273-3397) encodes a cysteine-rich fusion protein that was recognized by adherence-inhibitory anti-lectin monoclonal antibodies and serum antibodies from 95% of subjects with amebic liver abscess. Immunization of gerbils with purified recombinant LC3-encoded protein (10 micrograms) with Titermax adjuvant elicited a high-titer serum anti-LC3 IgG antibody response and protective immunity against intrahepatic challenge with 0.5 x 10(6) virulent axenic trophozoites (strain HM1:IMSS; 71% vaccine efficacy, P < .01). In summary, a recombinant cysteine-rich portion of the 170-kDa lectin subunit was highly antigenic, immunogenic, and effective as a subunit vaccine in an experimental animal model of amebic liver abscess.