Non-bacterial etiologies of diarrheal diseases in Afghanistan

BACKGROUND

Microbial diarrheal diseases are one of the leading causes of child morbidity and mortality in developing countries. This study aimed to identify the main causes of non-bacterial diarrhea in Afghanistan.

METHODS

A total of 699 stools were collected from children aged under 5 years who presented with diarrhea at Indira Gandhi and Kandahar hospitals. Frozen aliquots were preserved for screening against rotavirus, astrovirus, adenovirus, norovirus, Cryptosporidium and Giardia, when bacterial cultures tested negative. Tests were performed at the hospitals after laboratory staff were trained and provided with enzyme-immunoassays and equipment. Results were confirmed at the U.S. Naval Medical Research Unit No. 3, Cairo, Egypt.

RESULTS

Of the samples tested, 71.9% (503/699) were infected with one or more pathogens. However, the majority (85.8%; 432/503) showed single infections: rotavirus (72.2%; 329/432), Cryptosporidium (14.1%; 61/432), Giardia (5.1%; 22/432), astrovirus (2.3%; 10/432), adenovirus (1.6%; 7/432) and norovirus (0.7%; 3/432). The remaining 14% (71/503) showed mixed infections of the tested pathogens.

CONCLUSIONS

Non-bacterial pathogens were identified that could enable health officials to adopt more effective treatment and control measures for diarrhea in Afghanistan.

Heterogeneity of Campylobacter species isolated from serial stool specimens of Egyptian children using pulsed field gel electrophoresis

BACKGROUND

The genus Campylobacter spp. is a common cause of human acute bacterial enteritis and travellers' diarrhoea worldwide.

OBJECTIVE

To determine whether multiple serial isolations of Campylobacter spp., when obtained from a single child, represented the same or a different organism.

METHODS

In a birth cohort study conducted in Egypt, numerous children showed serial isolations of Campylobacter spp. Of these, 13 children were selected from different households based on the successive isolation of six or more Campylobacter isolates from stool samples.

RESULTS

Eighty isolates were recovered and identified as either Campylobacter coli (n = 25) or Campylobacter jejuni (n = 55). Pulsed-field gel electrophoresis (PFGE) revealed the presence of 38 unique C. jejuni and 24 C. coli profiles at a similarity level of ≥ 90%. Although no serially-identical isolates were detected in six children, others demonstrated at least one identical couple of isolates; all identified serially between one to six weeks. Two children demonstrated > 80% similar couples of isolates that appeared seven months apart. PFGE could be a useful tool for differentiating reinfection, relapse and convalescent excretion phases.

CONCLUSION

Our data suggest that Campylobacter infection in children is a complex process; children are exposed to multiple species in endemic environments and strains of the same bacterium appear to be shed serially between one to six weeks after the first exposure. Isolates that persisted for longer periods were relatively less similar, as shown from the results of this study.

Virological surveillance of influenza-like illness among children in Ghana, 2008-2010

BACKGROUND

The global annual attack rate for influenza is estimated to be 10%-20% in children, although limited information exists for Africa. In 2007, Ghana initiated influenza surveillance by routine monitoring of acute respiratory illness to obtain data on circulating strains. We describe influenza surveillance in children <11 years old who had influenza-like illness (ILI) from January 2008 to December 2010.

METHODS

Oropharyngeal swabs from pediatric outpatients with ILI attending any of 22 health facilities across the country were submitted. We tested swabs for influenza virus using molecular assays, virus isolation, and hemagglutination assays.

RESULTS

Of the 2810 swabs, 636 (23%) were positive for influenza virus. The percentage of positives by gender was similar. The proportion of ILI cases positive for influenza increased with age from 11% (31/275) in infants (aged 0-1 years) to 31% (377/1219) among children aged 5-10 years (P < .001). The majority of cases were influenza A (90%), of which 60% were influenza A(H1N1)pdm09. In all 3 years, influenza activity appeared slightly higher during May through July.

CONCLUSIONS

During the 3 years of influenza surveillance in Ghana, children aged <11 years bore a high burden of influenza-associated ILI.

Department of Defense influenza and other respiratory disease surveillance during the 2009 pandemic

The Armed Forces Health Surveillance Center's Division of Global Emerging Infections Surveillance and Response System (AFHSC-GEIS) supports and oversees surveillance for emerging infectious diseases, including respiratory diseases, of importance to the U.S. Department of Defense (DoD). AFHSC-GEIS accomplishes this mission by providing funding and oversight to a global network of partners for respiratory disease surveillance. This report details the system's surveillance activities during 2009, with a focus on efforts in responding to the novel H1N1 Influenza A (A/H1N1) pandemic and contributions to global public health. Active surveillance networks established by AFHSC-GEIS partners resulted in the initial detection of novel A/H1N1 influenza in the U.S. and several other countries, and viruses isolated from these activities were used as seed strains for the 2009 pandemic influenza vaccine. Partners also provided diagnostic laboratory training and capacity building to host nations to assist with the novel A/H1N1 pandemic global response, adapted a Food and Drug Administration-approved assay for use on a ruggedized polymerase chain reaction platform for diagnosing novel A/H1N1 in remote settings, and provided estimates of seasonal vaccine effectiveness against novel A/H1N1 illness. Regular reporting of the system's worldwide surveillance findings to the global public health community enabled leaders to make informed decisions on disease mitigation measures and controls for the 2009 A/H1N1 influenza pandemic. AFHSC-GEIS's support of a global network contributes to DoD's force health protection, while supporting global public health.

Shipboard impact of a probable Norwalk virus outbreak from coastal Japan

Norwalk virus has been implicated in shipboard diarrheal disease outbreaks throughout Asia. A large outbreak of suspected Norwalk virus was investigated on a U.S. Naval aircraft carrier following the clinical recognition of 450 cases of gastroenteritis over a 2-week period (September 14-28, 1997) during coastal exercises. A random sampling of 44 cases from 450 personnel who sought medical attention was compared with 19 controls. Junior enlisted sailors and marines comprised 97% of all cases. There was no evidence of shipboard geographic clustering of cases. Furthermore, no single food type was associated with illness on the basis of comparative analysis (cases versus controls). Principal case signs and symptoms reported included watery stools (89%), nausea (82%), and vomiting (77%). Anecdotal reports indicated > 50% of the cases received rehydration therapy. An absence of fever was also noted in 32% of the cases and only 5% had blood in their stools. The mean duration of illness was 37 hr, with a range of 3-96 hr. Laboratory findings based on reverse transcription-polymerase chain reaction and Southern hybridization methods showed that 21 (72%) of 29 patients had evidence of the UK2 prototype of the Norwalk virus. A cross-sectional study of 131 crew members from the ships population (n = 4,200) showed an attack rate of 44%. Attack rate is a variant of an incident rate applied to a narrowly defined population observed for a limited period of time, such as during an outbreak. The numerator is people who get sick and the denominator is people (population) at risk. An extrapolation of these findings suggests as many as 1,806 sailors may have been affected during the outbreak, of which only 26% (of the 57 outbreak related cases) where identified from sick call records. There was no difference in the mean ages between outbreak and non-outbreak affected crewmen, or geographic clustering based on berthing or work spaces. Outbreak-related cases reported signs and symptoms of watery-stools (79%), nausea (65%), and vomiting (47%). The mean duration of illness was 28 hr, ranging from 2 to 96 hr. Thirty-one percent of outbreak affected cases reported a sick call visit. Loss of work was reported by 39% of the outbreak affected population. This report documents the epidemic potential of Norwalk virus and the associated impact on fleet operational readiness. Additionally, that this outbreak occurred against a background of 3 other consecutive gastroenteritis outbreaks onboard the same ship (March 1997, February/March 1998, and June 1998), all sharing the same clinical and epidemiologic profiles, suggests possible shipboard persistence of Norwalk virus over time, despite periodic ship-wide disinfection efforts.

Cyclospora cayetanensis among expatriate and indigenous populations of West Java, Indonesia

From January 1995 through July 1998, we investigated the occurrence of Cyclospora cayetanensis infection associated with gastrointestinal illness or diarrhea in foreign residents and natives of West Java, Indonesia. We found that C. cayetanensis was the main protozoal cause of gastrointestinal illness and diarrhea in adult foreign residents during the wet season. The parasite rarely caused illness in the indigenous population or in children.

Comparison of preservation media for storage of stool samples

Transportation of clinical samples and long-term recoverability of pathogens are critical to epidemiological studies, particularly when conditions do not permit immediate processing. This study confirms that Cary-Blair medium (CB) is suitable for the preservation of Salmonella and Shigella isolates for more than 2 weeks at 25, 4, or -70 degrees C. Campylobacter jejuni was not recovered after 2 days of storage in CB at 25 degrees C when an inoculum of 12 x 10(8) cells per ml was used. Lower temperatures supported the recovery of this organism for 6 days. When individual pathogens were preserved with stools in CB and incubated at 25, 4, or -70 degrees C, the Salmonella and Shigella concentrations dropped from 12 x 10(8) cells to 1 x 10(3) or 1 x 10(4) cells per ml within 2 days and then remained stable for the rest of the observation period (15 days). C. jejuni survived preservation with stools for 5 to 9 days. The addition of blood and glycerol to CB improved the recoverability of all enteropathogens, particularly C. jejuni, which was consistently detected for 7 to 9 days at the different preservation temperatures used. When trypticase soy broth-glycerol (freezing medium), with or without blood, was used, there was little or no decrease in the Salmonella and Shigella concentrations during 2 weeks of preservation with stools at -70 degrees C. C. jejuni demonstrated a relatively sustained high concentration in Trypticase soy broth-glycerol with 5% blood. The use of defibrinated, laked sheep blood as a long-term freezing medium supported the recovery of low concentrations of Salmonella and Shigella spp. (10(2) to 10(3) cells per ml) for more than 14 weeks. Recovery of C. jejuni was consistent for 7 weeks when an initial concentration of 10(6) cells per ml present in stools. Laked blood provided a simple, sterile, and inexpensive medium for the preservation of individual isolates and clinical samples.