Longitudinal study of intestinal Entamoeba histolytica infections in asymptomatic adult carriers

To gain insight into the dynamics of intestinal Entamoeba histolytica infection, a longitudinal study was performed over an observation period of 15 months with a group of 383 randomly selected adult individuals (mean age, 38.5 years) living in an area of amebiasis endemicity in central Vietnam. Ameba infection was diagnosed by using species-specific PCR and DNA extracted directly from fecal samples. The results indicated an E. histolytica prevalence of 11.2% and an annual new infection rate of 4.1% in the study population. Follow-up of the 43 individuals who were E. histolytica positive at enrollment suggested a regular exponential decline in infection of about 3% per month and a mean half-life of infection of more than 15 months. However, the reinfection rate for this group of participants was 2.7 times higher than that predicted for the study population as a whole. Both the reappearance of the parasite after successful treatment of E. histolytica infection and changes in "genetic fingerprints" of parasites during the course of infection revealed an annual new infection rate of about 11.5%. Thus, the mean half-life of E. histolytica infection was calculated to be 12.9 months (95% confidence interval, 10.2 to 15.6 months). Notably, none of the participants developed symptoms compatible with invasive intestinal amebiasis, and only one of the subjects developed an amebic liver abscess during the observation period.     

Recent Advances in Our Understanding of the Environmental,Epidemiological, Immunological,and Clinical Dimensions of Coccidioidomycosis

SUMMARY

Coccidioidomycosis is the endemic mycosis caused by the fungal pathogens Coccidioides immitis and C. posadasii. This review is a summary of the recent advances that have been made in the understanding of this pathogen, including its mycology, genetics, and niche in the environment. Updates on the epidemiology of the organism emphasize that it is a continuing, significant problem in areas of endemicity. For a variety of reasons, the number of reported coccidioidal infections has increased dramatically over the past decade. While continual improvements in the fields of organ transplantation and management of autoimmune disorders and patients with HIV have led to dilemmas with concurrent infection with coccidioidomycosis, they have also led to advances in the understanding of the human immune response to infection. There have been some advances in therapeutics with the increased use of newer azoles. Lastly, there is an overview of the ongoing search for a preventative vaccine.     

Endemic mycoses in AIDS: a clinical review.

Histoplasmosis and coccidioidomycosis are serious opportunistic infections in patients with AIDS who reside in areas of endemicity of the United States and Central and South America. Blastomycosis, although less common, also must be recognized as an opportunistic infection in patients with AIDS. Prompt diagnosis requires knowledge of the clinical syndromes and diagnostic tests as well as a high index of suspicion. Histoplasmosis and blastomycosis respond well to antifungal treatment, but relapse is common without chronic suppressive therapy. Improvements in treatment are needed in coccidioidomycosis. Research is needed to identify preventive strategies for patients at risk. These strategies may include use of prophylactic antifungal therapy or vaccination.     

The Changing Epidemiology and Diagnosis of Valley Fever

Coccidioidomycosis, commonly known as valley fever, is a disease caused by two species of fungi, Coccidioides immitis and Coccidioides posadasii. Coccidioidomycosis is often self-limiting; however, in some patients, the disease can rapidly progress to a severe and potentially life-threatening illness. Proper diagnostics for coccidioidomycosis are important because acute disease can manifest as community-acquired pneumonia, and can be misdiagnosed as a viral or bacterial infection. Improper diagnosis can lead to unnecessary antibacterial therapy and may encourage extra-pulmonary proliferation of the fungus, which then requires longer antifungal therapy. Although coccidioidomycosis is caused by two different species, in terms of symptoms, disease progression, or clinical diagnostics, there are no known differences between the species. Additionally, recent work has revealed that the distribution of the organism in the environment may be changing and that the organism exists in the environment beyond the region of high endemicity. Overall, disease incidence has risen, and it is not known if this represents a better reporting and diagnosis infrastructure, increased environmental load, or increasing pathogenicity. Discussed here are the most common approaches to diagnose coccidioidomycosis, as well as recent advances in our understanding of the changing epidemiology of the disease and the causative organism.     

Development of a novel antigen detection test for histoplasmosis.

Histoplasmosis is an important systemic fungal infection, particularly among immunocompromised individuals living or travelling in areas of endemicity, who, without antifungal therapy, may develop a progressive disseminated fatal infection. For such patients, the detection of antibody responses by immunodiffusion or complement fixation test is of limited use. In contrast, the detection of Histoplasma capsulatum circulating antigens may provide a more practical approach to the rapid diagnosis of the disease. Accordingly, an inhibition enzyme-linked immunosorbent assay (ELISA) for the detection of a 69- to 70-kDa H. capsulatum-specific determinant and incorporating a species-specific murine monoclonal antibody was developed. With sera from patients with different forms of the disease (n = 35), the overall sensitivity of the test was found to be 71.4%, while the specificity was found to be 98% with normal human sera from areas of endemicity (n = 44) and 85.4% with sera from patients with other chronic fungal or bacterial infections (n = 48). This novel, highly specific ELISA provides a significant addition to the existing diagnostic tests for the detection of histoplasmosis.     

Viral agents responsible for febrile respiratory illnesses among military recruits training in tropical Singapore

BackgroundMilitary personnel are highly susceptible to febrile respiratory illnesses (FRI), likely due to crowding, stress and other risk factors present in the military environment.ObjectiveOur objective was to investigate the viral etiological agents responsible for FRI among military recruits training in a tropical climate in Singapore.Study designFrom March 2006 through April 2007, a total of 1354 oropharyngeal (throat) swabs were collected from military recruits who reported sick with an oral temperature of ≥38 °C and a cough and/or sore throat. Real-time polymerase chain reaction (PCR) was used to assay for the presence of influenza A and B viruses and adenoviruses (H-AdV), and conventional PCR used for the remaining respiratory viruses in all specimens.ResultsInfluenza A virus was the dominant infection with a laboratory-confirmed incidence of 24% (326/1354) and a predominance of the H3N2 subtype. The temporal pattern for influenza A virus infections coincided with the nation-wide pattern in the civilian community. Detection rates of 12% (159/1354) and 2.7% (5/1354) were obtained for influenza B virus and other respiratory viruses, respectively.ConclusionsThe laboratory findings identified influenza A virus as the primary causative viral agent for FRI in the Singapore military, in strong contrast to findings from temperate countries and countries where recruits are often vaccinated for influenza. Our results suggest that influenza vaccination should be considered as a requirement to reduce the incidence of influenza infections. This is the first report describing respiratory infections in a tropical military setting, in a developed country in Asia.     

Tablet-Based Strength-Balance Training to Motivate and Improve Adherence to Exercise in Independently Living Older People: A Phase II Preclinical Exploratory Trial

Background

Reaction time, coordination, and cognition performance typically diminish in older adults, which may lead to gait impairments, falls, and injuries. Regular strength–balance exercises are highly recommended to reduce this problem and to improve health, well-being, and independence in old age. However, many older people face a lack of motivation in addition to other strong barriers to exercise. We developed ActiveLifestyle, an information technology (IT)-based system for active and healthy aging aiming at improving balance and strength. ActiveLifestyle is a training app that runs on a tablet and assists, monitors, and motivates older people to follow personalized training plans autonomously at home.

Objective

The objectives were to (1) investigate which IT-mediated motivation strategies increase adherence to physical exercise training plans in older people, (2) assess the impact of ActiveLifestyle on physical activity behavior change, and (3) demonstrate the effectiveness of the ActiveLifestyle training to improve gait speed.

Methods

A total of 44 older adults followed personalized, 12-week strength and balance training plans. All participants performed the exercises autonomously at home. Questionnaires were used to assess the technological familiarity and stage of behavior change, as well as the effectiveness of the motivation instruments adopted by ActiveLifestyle. Adherence to the exercise plan was evaluated using performance data collected by the app and through information given by the participants during the study. Pretests and posttests were performed to evaluate gait speed of the participants before and after the study.

Results

Participants were 75 years (SD 6), predominantly female (64%), held a trade or professional diploma (54%), and their past profession was in a sitting position (43%). Of the 44 participants who enrolled, 33 (75%) completed the study. The app proved to assist and motivate independently living and healthy older adults to autonomously perform strength–balance exercises (median 6 on a 7-point Likert scale). Social motivation strategies proved more effective than individual strategies to stimulate the participants to comply with the training plan, as well as to change their behavior permanently toward a more physically active lifestyle. The exercises were effective to improve preferred and fast gait speed.

Conclusions

ActiveLifestyle assisted and motivated independently living and healthy older people to autonomously perform strength–balance exercises over 12 weeks and had low dropout rates. The social motivation strategies were more effective to stimulate the participants to comply with the training plan and remain on the intervention. The adoption of assistive technology devices for physical intervention tends to motivate and retain older people exercising for longer periods of time.     

Simultaneously high prevalences of hepatitis B and C virus infections in a population in Putian County, China

This study investigated a rare area of endemicity with a high prevalence of both hepatitis B virus (HBV) and hepatitis C virus (HCV) infections, in Putian County, China. Among 1,050 subjects, the overall prevalence of HBsAg seropositivity was 15.8%, and that of anti-HCV seropositivity was 28.9%. Intrafamilial viral transmission might be the major cause of the high prevalence of HBV infection in this region. However, HCV infection was shown to be associated with the use of inadequately sterilized medical equipment.     

Analyses of Confirmed COVID-19 Cases Among Korean Military Personnel After Mass Vaccination

BackgroundThe military was one of the first groups in Korea to complete mass vaccination against the coronavirus disease 2019 (COVID-19) due to their high vulnerability to COVID-19. To confirm the effect of mass vaccination, this study analyzed the patterns of confirmed cases within Korean military units.MethodsFrom August 1 to September 15, 2021, all epidemiological data regarding confirmed COVID-19 cases in military units were reviewed. The number of confirmed cases in the units that were believed to have achieved herd immunity (i.e., ≥ 70% vaccination) was compared with the number of cases in the units that were not believed to have reached herd immunity (< 70% vaccination). Additionally, trends in the incidence rates of COVID-19 in the military and the entire Korean population were compared.ResultsBy August 2021, 85.60% of military personnel were fully vaccinated. During the study period, a total of 174 COVID-19 cases were confirmed in the 39 units. More local transmission (herd immunity group vs. non-herd immunity group [%], 1 [0.91] vs. 39 [60.94]) and hospitalizations (12 [11.01] vs. 13 [27.08]) occurred in the units that were not believed to have achieved herd immunity. The percentage of fully vaccinated individuals among the confirmed COVID-19 cases increased over time, possibly due to the prevalence of the delta variant. Nevertheless, the incidence rate remained lower in military units than in the general Korean population.ConclusionAfter completing mass vaccination, the incidence rates of COVID-19 infection in the military were lower than those in the national population. New cluster infections did not occur in vaccinated units, thereby suggesting that herd immunity has been achieved in these military units. Further research is needed to determine the extent to which levels of non-pharmacological intervention can be reduced in the future.     

Mycology in the Philippines, revisited.

The warm tropical climate of the Philippines and its interaction with cultural practices, occupation and immune responsiveness contribute to the increased susceptibility of Filipinos to fungal infections. An investigation to determine the prevalence of fungal infections in dermatology training institutions over a 4-year period was conducted. The results showed that fungal infections rank as the second leading cause of consultation with a prevalence of 12.98%. Pityriasis versicolor (25.34%), tinea corporis (22.63%), tinea cruris (16.7%) and tinea pedis (16.38%) were the most frequently encountered cases. Fungal culture yield is low and Candida sp. is the most common isolate, obtained predominantly from specimens taken from the oral mucosa and nails. Candidiasis is still the most common opportunistic infection followed by coccidioidomycosis, cryptococcosis and aspergillosis. Imidazoles are the most commonly prescribed systemic and topical treatment by Filipino dermatologists. Initial data collected would serve as reference for future research and may be used to compare with epidemiologic data obtained from other Asian countries.     

Cutaneous microenvironment of human immunodeficiency virus (HIV)-seropositive and HIV-seronegative individuals, with special reference to Staphylococcus aureus colonization

A cross-sectional quantitative study of cutaneous bacterial and yeast flora at seven body sites in 99 human immunodeficiency virus-seropositive and 50 seronegative military personnel was performed. Statistically significant differences in carriage rates were only observed for Staphylococcus aureus on the foreheads of seropositive individuals. Seronegative individuals demonstrated staphylococcal carriage rates 1.3 to 2 times as great as those of historical controls (defined as healthy individuals not receiving any medications) at five of six body sites. We conclude that seropositive military personnel do not exhibit statistically significant elevations in densities and carriage rates of the microorganisms examined (except Staphylococcus aureus), relative to seronegative individuals. Seropositive individuals may be predisposed to staphylococcal carriage. The elevated staphylococcal carriage rates of military personnel undergoing basic training warrants a formal evaluation of the impact of training exercises on cutaneous flora. The information gained may serve to limit the spread of infection during training exercises and battlefield conditions.     

Risk factors for community-associated methicillin-resistant Staphylococcus aureus infections in an outbreak of disease among military trainees in San Diego, California, in 2002

An outbreak of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) skin infections was observed in a population of U.S. military trainees in the summer of 2002. A questionnaire was developed and administered to 206 trainees, 22 of whom had MRSA infections. Factors associated with infection were described by multivariable logistic regression modeling and included having a roommate in training with a prior skin infection (odds ratio [OR] = 3.44) or having a family member or friend who worked in a health care setting (OR = 2.79). Previous antibiotic use, hospitalization, or health problems were not associated with MRSA infection. This outbreak of MRSA skin infections in an otherwise-healthy, well-defined, military population provided an opportunity to describe risk factors for CA-MRSA which may help focus prevention efforts in this and other communities.     

Reactivation of coccidioidomycosis: a prosthetic joint infection in Spain

A resident of Spain was found to have a prosthetic knee infection due to coccidioidomycosis. He had a history of having pneumonia which resolved while living in an area of California endemic for Coccidioides in 1957–1961. The patient left California in 1961 returned to Spain and never left Spain thereafter. In 2006, a total knee replacement was done. In 2013, a prosthetic knee infection was documented due to coccidioidomycosis. By molecular DNA analysis, Coccidioides immitis was identified from the knee tissue, a species most commonly found in California. This represents reactivation of a Coccidioides infection 56 years after leaving the endemic area.     

Posttransplantation disseminated coccidioidomycosis acquired from donor lungs

A North Carolinian developed fatal coccidioidomycosis immediately after bilateral lung transplantation. The donor had previously traveled to Mexico, and the recipient had no travel history to an area where Coccidioides immitis is endemic. Immunosuppressive therapy of the transplant recipient likely reactivated latent Coccidioides infection in the donor lungs, leading to posttransplant coccidioidomycosis.     

Portage parasitaire intestinal chez l’enfant scolarisé à Salé, Maroc

Intestinal parasitic infections are among the most widespread of human infections in developing countries, and children are the most vulnerable. The aim of this study was to determine the prevalence of protozoa and intestinal helminthes, as well as the risk factors of intestinal parasites in schoolchildren in Salé city, Morocco. This is a study of incidence and prevalence conducted prospectively over a period of five months in schoolchildren in Salé city. The collection of stool was performed over three days (j1, j3, j5). In addition, adhesive cellophane tape slide evaluation was performed on day 7 for all students included in this work. During the study period, we included 123 students. Seventy-six children (61.7%) were infected by intestinal parasites. The age group 12?C14 years is by far the most affected. Protozoa were found in 57.7% (N = 71) of children examined. Amoebae family parasites were predominant. Helminths were present in 26% (N = 32) of the schoolchildren. Forty-five (36.6%) children were poly-parasitized. This work shows that the prevalence of intestinal parasitism is quite high among primary schoolchildren in Salé city. Several parasite species are found. This finding is explained by unhealthy living conditions and poor hygiene, predisposing to endemicity and perpetuation of the transmission. The impact on health is not negligible especially when compounded by malnutrition. The best way to fight this scourge is prevention and awareness.     

Hepatitis B virus infection in a group of heterosexuals with multiple partners in Amsterdam,The Netherlands: Implications for vaccination?

The aim of the study was to assess prevalence and incidence of hepatitis B virus (HBV) infection among heterosexual men and women with multiple partners attending a sexually transmitted disease (STD) clinic and to establish risk factors of HBV infection in order to consider immunisation for those subjects. A prospective study of heterosexual men and women selected on having multiple partners and presenting to an STD clinic as new patients was carried out from October 1987 through December 1989. Follow-up continued until December 1990 at the STD clinic of the Municipal Health Service of Amsterdam. Five hundred ninety-eight men and women entered the study. More than 70% of both women and men had had commercial sexual partners in the last 5 years. Three hundred eighty-one participants were born in HBV low endemic countries, 205 came from HBV intermediate endemicity regions. The prevalence of HBV markers in both men and women from low endemic regions was 10%, and for men and women from middle endemic regions 42% and 19%, respectively. Logistic regression analysis showed that number of years involved in commercial sex was an independent risk factor in male participants from HBV low endemic regions (odds ratio [OR] 1.10 per year) and for women sexual contact with men at high risk of HBV infection (OR 2.59). In people from middle endemic regions more men than women had HBV markers, HBV-positive men were older than HBV-negatives (OR 1.05 per year), and for HBV-positive women the number of years involved in commercial sex was an independent predictor (OR 1.23 per year). No new cases of HBV infection were found in both groups (upper 95% limit of confidence 7.1 per 1,000 and 35.8 per 1,000 for the participants from low and middle endemic countries, respectively). The duration of follow-up was 419.9 person-years at risk for the group from low endemic regions and 83.7 person-years for the people from middle endemic regions. The participants must be considered to have been at continuous high risk of heterosexual transmission. The incidence of HBV was so tow that we decided for the moment not to offer hepatitis B vaccination to all heterosexual men and women attending our STD clinic. © 1994 Wiley-Liss, Inc.     

Screening for Escherichia coli O157:H7 in Illinois

Objective: To determine the incidence of infection with Escherichia coli O157:H7 in a tertiary referral center in Chicago, where a similar study had been performed in 1984, to evaluate cases of disease reported to the Illinois Department of Public Health (IDPH) in 1993, and to determine laboratory practices used to detect this infection throughout the state.
Methods: During a 6-month period in 1993, all stool specimens at Rush-Presbyterian-St Luke's Medical Center (RPSLMC) were tested for E. coli O157:H7. Reports of diagnosed E. coli O157:H7 cases investigated by IDPH were also reviewed. A survey of 73 hospitals in the Chicago area was performed to determine routine culturing practices, specifically, the selection of stool specimens for evaluation for this pathogen.
Results: In the RPSLMC survey, two cases were identified among 1985 samples (incidence 0.1%), similar to the 0.08% incidence detected in a similar study conducted at the same institution in 1984. Through passive surveillance, the IDPH received 44 reports of E. coli O157:H7 in 1993. The hospital survey revealed that, in the seven labs testing all stool specimens for E. coli O157:H7, an incidence of 16/8137 specimens (0.2%) was determined.
Conclusions: These data suggest that sporadic E. coli O157:H7 remains uncommon in Illinois and that the incidence may not have changed over a 9-year period. The low yield and substantial cost of culturing all stools suggest that only specimens from patients with bloody diarrhea should be evaluated routinely in areas of low endemicity.     

False-Positive IgM Serology in Coccidioidomycosis

The clinical observation has been made that there might be an unacceptable number of false-positive enzyme immunoassay (EIA) test results for IgM among persons suspected of having coccidioidomycosis. Patients with a positive result for IgM by EIA are thought to have a diagnosis of acute coccidioidomycosis. However, this study found that 82% of patients with an IgM-positive and IgG-negative EIA result did not have coccidioidomycosis.The Premier Coccidioides enzyme immunoassay (EIA; Meridian Bioscience, Inc., Cincinnati, OH) is a commercially available test used for the serological diagnosis of coccidioidomycosis. Clinical laboratories use that EIA for the detection of both IgM and IgG antibodies directed against Coccidioides. A positive EIA result for IgM is believed to be associated with the initial antibody response seen in an acute Coccidioides infection (3). The EIA test is also used to determine the presence of IgG antibody, which is diagnostic of an infection with Coccidioides. Clinicians use the various IgM and IgG antibody responses to determine the presence or the absence of an acute or a chronic Coccidioides infection (5).The Premier assay may be subject to false-positive results for IgM, as suggested by prior studies (2, 3). In contrast, those clinical and serological studies found a good correlation between a positive result for IgG by the Premier assay and infection with Coccidioides.A false-positive EIA result for IgM occurs when patients are thought to be experiencing acute coccidioidomycosis but do not have a Coccidioides infection. Clinical observations have raised concern that there may be an unacceptable number of false-positive IgM results with the Premier assay. A false-positive serological result can create clinical problems, resulting in the treatment of patients for a disease that they do not have or thinking that the patient has coccidioidomycosis and missing another medical condition. The study described here was done to correlate clinical findings and serological results for patients who had a positive result for IgM and a negative result for IgG by the Premier Coccidioides EIA.     

Hepatitis B virus and sexual behavior in Rakai, Uganda

HIV and hepatitis B virus (HBV) co-infection poses important public health considerations in resource-limited settings. Demographic data and sera from adult participants of the Rakai Health Sciences Program Cohort in Southwestern Uganda were examined to determine HBV seroprevalence patterns in this area of high HIV endemicity prior to the introduction of anti-retroviral therapy. Commercially available EIAs were used to detect prevalent HBV infection (positive for HBV core antibody [anti-HBc] and/or positive HBV surface antigen [HBsAg]), and chronic infection (positive for HBsAg). Of 438 participants, 181 (41%) had prevalent HBV infection while 21 (5%) were infected chronically. Fourteen percent of participants were infected with HIV. Fifty three percent showed evidence of prevalent HBV infection compared to 40% among participants infected with HIV (P = 0.067). Seven percent of participants infected with HIV were HBsAg positive compared to 4% among participants not infected with HIV (P = 0.403). The prevalence of prevalent HBV infection was 55% in adults aged >50 years old, and 11% in persons under 20 years. In multivariable analysis, older age, HIV status, and serologic syphilis were significantly associated with prevalent HBV infection. Transfusion status and receipt of injections were not significantly associated with HBV infection. Contrary to expectations that HBV exposure in Uganda occurred chiefly during childhood, prevalent HBV infection was found to increase with age and was associated sexually transmitted diseases (HIV and syphilis.) Therefore vaccination against HBV, particularly susceptible adults with HIV or at risk of HIV/STDs should be a priority.     

A low incidence of nontuberculous mycobacterial infections in pediatric hematopoietic stem cell transplantation recipients.

Hematopoietic stem cell transplantation (HSCT) is being used to treat a wide spectrum of clinical disorders but opportunistic infection remains an important factor determining outcomes for these patients. Nontuberculous mycobacterial (NTM) infections are being reported more frequently in HSCT recipients and the incidence of NTM infections in adult recipients is reported to be 0.4%-4.9%. However, the incidence and severity of NTM infections are less well described in pediatric HSCT recipients. Centers for Disease Control and Prevention guidelines were used to define definite and probable NTM infection among 132 children undergoing 169 HSCT between January 2000 and December 2004 at our institution. NTM infection was diagnosed in 5 of 132 pediatric recipients (3.8%). There were no NTM infections diagnosed in the autologous HSCT recipients and the incidence of NTM in allogeneic HSCT recipients was 6.4% (95% confidence interval, 0.8-11.9). The mean age of the HSCT recipients who developed NTM infections was 8 years (range, 2-19 years); 3 were male and 2 were female. Four conditioning regimens included alemtuzumab and 3 had antithymocyte globulin. Of the 5 patients with NTM infections, 2 met the criteria for definite infection and 3 for probable infection. Of the 2 patients with definite NTM infection, 1 had disseminated disease with Mycobacterium avium complex and the other had Mycobacterium chelonae catheter-related bloodstream infection. The probable NTM infections were 1 skin infection with Mycobacterium kansasii and 2 lower respiratory tract infections with M avium complex. Median time to NTM infection was 115 days (range, 14-269 days) after HSCT. Two patients had graft-versus-host disease at the time of NTM infection. All 5 patients received 3-4 antimycobacterial drugs and all NTM infections resolved. In summary, the incidence of NTM infection in pediatric HSCT recipients appears similar to that described in adult HSCT recipients and the outcome appears to be excellent with the proper antibiotic therapy. The increased use of anti-T cell antibodies appears to be associated with an increased risk of NTM infections in pediatric HSCT recipients. Multicenter studies are needed to identify the risk factors, early diagnostic criteria, and optimal therapy.