Risk factors for the initial symptomatic giardia infection in a cohort of young Arab-Bedouin children

Determinants of Childhood Zoonotic Enteric Infections in a Semirural Community of Quito, Ecuador

Domestic animals in the household environment have the potential to affect a child's carriage of zoonotic enteric pathogens and risk of diarrhea. This study examines the risk factors associated with pediatric diarrhea and carriage of zoonotic enteric pathogens among children living in communities where smallholder livestock production is prevalent. We conducted an observational study of children younger than 5 years that included the analysis of child (n = 306) and animal (n = 480) fecal samples for Campylobacter spp., atypical enteropathogenic Escherichia coli, Shiga toxin-producing E. coli, Salmonella spp., Yersinia spp., Cryptosporidium parvum, and Giardia lamblia. Among these seven pathogens, Giardia was the most commonly identified pathogen among children and animals in the same household, most of which was found in child-dog pairs. Campylobacter spp. was also relatively common within households, particularly among child-chicken and child-guinea pig pairs. We used multivariable Poisson regression models to assess risk factors associated with a child being positive for at least one zoonotic enteric pathogen or having diarrhea during the last week. Children who interacted with domestic animals-a behavior reported by nearly three-quarters of households owning animals-were at an increased risk of colonization with at least one zoonotic enteric pathogen (prevalence ratio [PR] = 1.56, 95% CI: 1.00-2.42). The risk of diarrhea in the last seven days was elevated but not statistically significant (PR = 2.27, CI: 0.91, 5.67). Interventions that aim to reduce pediatric exposures to enteric pathogens will likely need to be incorporated with approaches that remove animal fecal contamination from the domestic environment and encourage behavior change aimed at reducing children's contact with animal feces through diverse exposure pathways.

Impact of Childhood Malnutrition on Host Defense and Infection

The global impact of childhood malnutrition is staggering. The synergism between malnutrition and infection contributes substantially to childhood morbidity and mortality. Anthropometric indicators of malnutrition are associated with the increased risk and severity of infections caused by many pathogens, including viruses, bacteria, protozoa, and helminths. Since childhood malnutrition commonly involves the inadequate intake of protein and calories, with superimposed micronutrient deficiencies, the causal factors involved in impaired host defense are usually not defined. This review focuses on literature related to impaired host defense and the risk of infection in primary childhood malnutrition. Particular attention is given to longitudinal and prospective cohort human studies and studies of experimental animal models that address causal, mechanistic relationships between malnutrition and host defense. Protein and micronutrient deficiencies impact the hematopoietic and lymphoid organs and compromise both innate and adaptive immune functions. Malnutrition-related changes in intestinal microbiota contribute to growth faltering and dysregulated inflammation and immune function. Although substantial progress has been made in understanding the malnutrition-infection synergism, critical gaps in our understanding remain. We highlight the need for mechanistic studies that can lead to targeted interventions to improve host defense and reduce the morbidity and mortality of infectious diseases in this vulnerable population.

Livestock ownership and microbial contamination of drinking-water: Evidence from nationally representative household surveys in Ghana, Nepal and Bangladesh

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Owning livestock can increase the risk of drinking-water contamination.

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Large livestock were associated with water contamination in Ghana and Bangladesh.

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Poultry were associated with drinking-water contamination in Bangladesh.

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Livestock were not significantly correlated with water contamination in Nepal.

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Livestock excreta should be considered for the prevention of water contamination.

Background

Current priorities for diarrhoeal disease prevention include use of sanitation and safe water. There have been few attempts to quantify the importance of animal faeces in drinking-water contamination, despite the presence of potentially water-borne zoonotic pathogens in animal faeces.

Objectives

This study aimed to quantify the relationship between livestock ownership and point-of-consumption drinking-water contamination.

Methods

Data from nationally representative household surveys in Nepal, Bangladesh, and Ghana, each with associated water quality assessments, were used. Multinomial regression adjusting for confounders was applied to assess the relationship between livestock ownership and the level of drinking-water contamination with E. coli.

Results

Ownership of five or more large livestock (e.g. cattle) was significantly associated with drinking-water contamination in Ghana (RRR = 7.9, 95% CI = 1.6 to 38.9 for medium levels of contamination with 1–31cfu/100 ml; RRR = 5.2, 95% CI = 1.1–24.5 for high levels of contamination with >31cfu/100 ml) and Bangladesh (RRR = 2.4, 95% CI = 1.3–4.5 for medium levels of contamination; non-significant for high levels of contamination). Ownership of eight or more poultry (chickens, guinea fowl, ducks or turkeys) was associated with drinking-water contamination in Bangladesh (RRR = 1.5, 95% CI = 1.1–2.0 for medium levels of contamination, non-significant for high levels of contamination).

Conclusions

These results suggest that livestock ownership is a significant risk factor for the contamination of drinking-water at the point of consumption. This indicates that addressing human sanitation without consideration of faecal contamination from livestock sources will not be sufficient to prevent drinking-water contamination.

What is Known About Health and Morbidity in the Pediatric Population of Muslim Bedouins in Southern Israel: A Descriptive Review of the Literature from the Past Two Decades

The Bedouins comprise one of the ethnic groups in Israeli society. They are Muslims, most of who live in the Negev desert region of southern Israel and live by their unique traditions and customs. At the present they are going through a period of "society in transition", a unique condition that has ramifications for health and morbidity. In recent years the number of publications on the health of Bedouins in the Negev has increased. Recognition of unique socio-economic features, characteristics of health and diseases can help the medical team treat various health problems in this population as well as other populations with similar characteristics. In the present paper we survey and discuss publications on the health of Bedouin children over the past 20 years.

Human diarrhea infections associated with domestic animal husbandry: a systematic review and meta-analysis

Domestic animal husbandry, a common practice globally, can lead to zoonotic transmission of enteric pathogens. However, this risk has received little attention to date. This systematic review and meta-analysis examines the evidence for an association between domestic exposure to food-producing animals and cases of human diarrhea and specific enteric infections. We performed a systematic review of available literature to examine domestic livestock and poultry as risk factors for diarrhea and applied pre-determined quality criteria. Where possible, we carried out meta-analysis of specific animal-pathogen pairs. We found consistent evidence of a positive association between exposure to domestic food-producing animals and diarrheal illness across a range of animal exposures and enteric pathogens. Out of 29 studies included in the review, 20 (69.0%) reported a positive association between domestic animal exposure and diarrhea. Domestic exposure to poultry revealed a substantial association with human campylobacteriosis (OR 2.73, 95% CI 1.90-3.93). Our results suggest that domestic poultry and livestock exposures are associated with diarrheal illness in humans. Failure to ascertain the microbial cause of disease may mask this effect. Exposure to domestic animals should be considered a risk factor for human diarrheal illness and additional studies may identify potential mitigation strategies to address this risk.

Differences in prevalence of parasites in stool samples between three distinct ethnic pediatric populations in southern Israel, 2007-2011

Intestinal parasites cause significant morbidity worldwide, particularly in developing populations. At least three pediatric populations reside in southern Israel: the Bedouin population, the general Jewish population and Jewish children of Ethiopian origin. Our aim was to compare intestinal parasite prevalence between the three pediatric populations in southern Israel. This is a retrospective, laboratory, population-based surveillance. Most ova and parasite (O&P) tests in southern Israel (hospital and community obtained) are performed by the hospital parasitology laboratory. All pediatric stool O&P tests examined by the hospital laboratory between 2007 and 2011 were included. Overall, 45,978 samples were examined; 27,354, 16,969 and 1655 from Bedouin, non-Ethiopian Jewish and Ethiopian children, respectively. 16,317 parasites were identified in 12,325 (26.8%) positive samples. Total prevalences were 36%, 11% and 46% for Bedouin, non-Ethiopian Jewish and Ethiopian children, respectively. Blastocystis hominis, Giardia lamblia and Entamoeba species were the most common parasites identified, constituting ≥80% of positive samples in all groups. Hymenolepis nana was rarely identified in non-Ethiopian Jewish children (0.04% of isolates compared with 2.6% and 0.5% in Bedouin and Ethiopian children, respectively). Other helminths, excluding H. nana and Enterobius vermicularis, were identified almost exclusively in Ethiopian children ≥5years of age. In conclusion, the Bedouin and Ethiopian children were characterized by higher parasite prevalence in stool, compared with the non-Ethiopian Jewish children, probably reflecting higher intestinal parasitic disease rates. Certain helminthic infections were identified almost exclusively in the Ethiopian children. These differences may be associated with lifestyle differences between the three populations.

Transmission and epidemiology of zoonotic protozoal diseases of companion animals

Over 77 million dogs and 93 million cats share our households in the United States. Multiple studies have demonstrated the importance of pets in their owners' physical and mental health. Given the large number of companion animals in the United States and the proximity and bond of these animals with their owners, understanding and preventing the diseases that these companions bring with them are of paramount importance. Zoonotic protozoal parasites, including toxoplasmosis, Chagas' disease, babesiosis, giardiasis, and leishmaniasis, can cause insidious infections, with asymptomatic animals being capable of transmitting disease. Giardia and Toxoplasma gondii, endemic to the United States, have high prevalences in companion animals. Leishmania and Trypanosoma cruzi are found regionally within the United States. These diseases have lower prevalences but are significant sources of human disease globally and are expanding their companion animal distribution. Thankfully, healthy individuals in the United States are protected by intact immune systems and bolstered by good nutrition, sanitation, and hygiene. Immunocompromised individuals, including the growing number of obese and/or diabetic people, are at a much higher risk of developing zoonoses. Awareness of these often neglected diseases in all health communities is important for protecting pets and owners. To provide this awareness, this review is focused on zoonotic protozoal mechanisms of virulence, epidemiology, and the transmission of pathogens of consequence to pet owners in the United States.

A systematic review and meta-analysis of the association between Giardia lamblia and endemic pediatric diarrhea in developing countries

We performed a systematic literature review and meta-analysis examining the association between diarrhea in young children in nonindustrialized settings and Giardia lamblia infection. Eligible were case/control and longitudinal studies that defined the outcome as acute or persistent (>14 days) diarrhea, adjusted for confounders and lasting for at least 1 year. Data on G. lamblia detection (mainly in stools) from diarrhea patients and controls without diarrhea were abstracted. Random effects model meta-analysis obtained pooled odds ratios (ORs) and 95% confidence intervals (CIs). Twelve nonindustrialized-setting acute pediatric diarrhea studies met the meta-analysis inclusion criteria. Random-effects model meta-analysis of combined results (9774 acute diarrhea cases and 8766 controls) yielded a pooled OR of 0.60 (95% CI, .38-.94; P = .03), indicating that G. lamblia was not associated with acute diarrhea. However, limited data suggest that initial Giardia infections in early infancy may be positively associated with diarrhea. Meta-analysis of 5 persistent diarrhea studies showed a pooled OR of 3.18 (95% CI, 1.50-6.76; P < .001), positively linking Giardia with that syndrome. The well-powered Global Enteric Multicenter Study (GEMS) is prospectively addressing the association between G. lamblia infection and diarrhea in children in developing countries.

Animal livestock and the risk of hospitalized diarrhoea in children under 5 years in Vietnam

OBJECTIVE

To investigate the association between environmental exposure to livestock and incidence of diarrhoea among Vietnamese children.

METHODS

A population-based cohort of 353,525 individuals, living in 75,828 households in Khanh Hoa Province, Vietnam, with baseline data covering geo-referenced information on demography, socio-economic status and household animals was investigated. Geographic information system was applied to calculate the density of livestock. The data were linked to hospitalized diarrhoea cases of children under 5 years recorded at two hospitals treating patients from the area as inpatients in the study area.

RESULTS

Overall, 3116 children with diarrhoea were hospitalized during the study period. The incidence of diarrhoea hospitalization was 60.8/1000 child-years. Male gender, age <2 years, higher number of household members and lack of tap water were significantly associated with an increased risk of diarrhoea. There was no evidence that ownership of livestock increased the risk of diarrhoea. In spatial analysis, we found no evidence that a high density of any animals was associated with an increased risk of diarrhoea.

CONCLUSIONS

Exposure to animals near or in households does not seem to constitute a major risk for diarrhoea in children under the age of 5 in Vietnam. Public health interventions to reduce childhood diarrhoea burden should focus on well-recognized causes such as sanitation, personal hygiene, access to adequate clean water supply and vaccination.

Risk factors for Giardia infection among hospitalized children in Cuba

The risk factors associated with Giardia infection, in children hospitalized in Havana, Cuba, were recently explored. Children aged ≥5 years were more likely to be positive for Giardia infection than the younger children, with an odds ratio (OR) of 3·41 [95% confidence interval (CI) = 1·36-9·69]. The risk factors found to be associated with Giardia infection in univariate analyses were rural residence (OR = 3·01; CI = 1·23-7·35), belonging to a household that did not receive water from an aqueduct (OR = 3·27; CI = 1·21-8·91), drinking unboiled water (OR = 3·64; CI = 2·14-6·26), nail biting (OR = 3·47; CI = 1·97-6·08), eating unwashed vegetables raw (OR = 4·84; CI = 2·33-10·14), and a personal (OR = 3·23; CI = 1·58-6·59) or family history (OR = 3·96; CI = 1·53-10·47) of previous parasitic infection. In multivariate analyses, however, only two (modifiable) risk factors were found to be independently and significantly associated with Giardia infection: nail biting and eating unwashed vegetables raw. It therefore seems that, at least at the individual level, giardiasis-prevention activities in Havana should be focussed on health education to improve personal hygiene and food-related practices. If appropriately managed, the surveillance of drinking water and foodstuffs, for Giardia and other parasites, might also help to reduce the hospitalization of Cuban children.

Interactions of diarrhea, pneumonia, and malnutrition in childhood: recent evidence from developing countries

PURPOSE OF REVIEW

This review highlights recent progress toward understanding complex interactions between diarrhea, pneumonia, and undernutrition among children in low-income and middle-income countries.

RECENT FINDINGS

New studies parallel earlier reports that diarrhea and pneumonia impair children's growth and that underlying malnutrition is a major risk factor for these conditions. Episodes of diarrhea may predispose to pneumonia in undernourished children. Additional studies support breastfeeding and micronutrient supplementation for the prevention and control of diarrhea and pneumonia. Malnutrition may partially account for the reduced efficacy of oral rotavirus vaccines in low-income countries. Immunization of pregnant women against influenza also appears to reduce intrauterine growth retardation. Immunization of infants against Streptococcus pneumoniae may improve their growth. New genetic studies indicate that polymorphisms in apolipoprotein E or the leptin receptor modulate children's risk for diarrhea and Entamoeba histolytica infection, respectively, thereby linking two genes important for lipid metabolism to enteric infections.

SUMMARY

Significant advances have been made in understanding the vicious cycle of malnutrition, diarrhea, and pneumonia in developing countries. Future challenges will be to translate this progress into effective and widely accessible public health measures.

Impact of Giardia lamblia on growth, serum levels of zinc, copper, and iron in Egyptian children

The aim of this study is to evaluate the serological levels of zinc, copper and iron in Giardia lamblia-infected children and to study the effect of giardiasis on their weight compared to controls. We studied 30 children, 1-10 years old, who attended the outpatient clinics of Cairo University Pediatric Hospital, with gastrointestinal complaints and diagnosed as having giardiasis by stools examination, they were enrolled as a study group. The control group consisted of 30 age- and sex-matched healthy children, free of gastrointestinal complaints and free of giardiasis. Serological levels of zinc, copper, and iron were measured by atomic absorption spectrophotometer. The infected group had significantly lower weight, serum iron, and zinc than controls (P = 0.035, <0.001, and <0.001 respectively) and 63.3% of patients infected with giardiasis were 1-5 years old. In the infected cases, 60% suffered from of abdominal pain, 50% from weight loss, and 40% had intermittent diarrhea. Infected cases with weight percentiles below the fifth had significantly lower serum iron than those with normal percentiles (>5th). In conclusion, most giardiasis-infected children were between 1 and 5 years, with significant affection of weight, abdominal pain, and/or intermittent diarrhea. Serum zinc and iron levels were significantly decreased in the infected group compared to control (P < 0.001).

Update on prolonged and persistent diarrhea in children

PURPOSE OF REVIEW

To highlight recent advances in our understanding of prolonged episodes of acute diarrhea and persistent diarrhea in children. The focus is on the contribution of these illnesses to the global burden of diarrhea, their impact on childhood growth and development, novel epidemiologic links between prolonged and persistent diarrheal episodes, and strategies for their prevention and management.

RECENT FINDINGS

Although less common than acute diarrhea, prolonged and persistent episodes of diarrhea in childhood constitute a significant portion of the global burden of diarrhea. These episodes also play a key role in the vicious cycle of childhood diarrhea and malnutrition in which undernutrition is both a risk factor and an outcome of diarrhea. Increased efforts to provide WHO-recommended zinc therapy for all children with diarrhea in developing countries will significantly reduce morbidity and mortality. In children who develop persistent diarrhea, yogurt-based or amino acid-based diets may accelerate their recovery.

SUMMARY

In addition to increased implementation of strategies already known to effectively prevent and manage acute diarrhea, further research is needed to address the recognition, prevention, and treatment of prolonged episodes of acute diarrhea and persistent diarrhea in resource-limited settings.